A verification and validation effort for high explosives at Los Alamos National Lab (u)

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

Scovel, Christina A; Menikoff, Ralph S

2009-01-01

We have started a project to verify and validate ASC codes used to simulate detonation waves in high explosives. Since there are no non-trivial analytic solutions, we are going to compare simulated results with experimental data that cover a wide range of explosive phenomena. The intent is to compare both different codes and different high explosives (HE) models. The first step is to test the products equation of state used for the HE models, For this purpose, the cylinder test, flyer plate and plate-push experiments are being used. These experiments sample different regimes in thermodynamic phase space: the CJ isentropemore » for the cylinder tests, the isentrope behind an overdriven detonation wave for the flyer plate experiment, and expansion following a reflected CJ detonation for the plate-push experiment, which is sensitive to the Gruneisen coefficient. The results of our findings for PBX 9501 are presented here.« less

Initiation and structures of gaseous detonation

NASA Astrophysics Data System (ADS)

Vasil'ev, A. A.; Vasiliev, V. A.

2018-03-01

The analysis of the initiation of a detonation wave (DW) and the emergence of a multi-front structure of the DW-front are presented. It is shown that the structure of the DW arises spontaneously at the stage of a strong overdriven of the wave. The hypothesis of the gradual enhancement of small perturbations on an initially smooth initiating blast wave, traditionally used in the numerical simulation of multi-front detonation, does not agree with the experimental data. The instability of the DW is due to the chemical energy release of the combustible mixture Q. A technique for determining the Q-value of mixture was proposed, based on reconstruction of the trajectory of the expanding wave from the position of the strong explosion model. The wave trajectory at the critical initiation of a multifront detonation in a combustible mixture is compared with the trajectory of an explosive wave from the same initiator in an inert mixture whose gas-dynamic parameters are equivalent to the parameters of the combustible mixture. The energy release of a mixture is defined as the difference in the joint energy release of the initiator and the fuel mixture during the critical initiation and energy release of the initiator when the blast wave is excited in an inert mixture. Observable deviations of the experimental profile of Q from existing model representations were found.

Detonation waves in pentaerythritol tetranitrate

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

Tarver, C.M.; Breithaupt, R.D.; Kury, J.W.

1997-06-01

Fabry{endash}Perot laser interferometry was used to obtain nanosecond time resolved particle velocity histories of the free surfaces of tantalum discs accelerated by detonating pentaerythritol tetranitrate (PETN) charges and of the interfaces between PETN detonation products and lithium fluoride crystals. The experimental records were compared to particle velocity histories calculated using very finely zoned meshes of the exact dimensions with the DYNA2D hydrodynamic code. The duration of the PETN detonation reaction zone was demonstrated to be less than the 5 ns initial resolution of the Fabry{endash}Perot technique, because the experimental records were accurately calculated using an instantaneous chemical reaction, the Chapman{endash}Jouguetmore » (C-J) model of detonation, and the reaction product Jones{endash}Wilkins{endash}Lee (JWL) equation of state for PETN detonation products previously determined by supracompression (overdriven detonation) studies. Some of the PETN charges were pressed to densities approaching the crystal density and exhibited the phenomenon of superdetonation. An ignition and growth Zeldovich{endash}von Neumann{endash}Doring (ZND) reactive flow model was developed to explain these experimental records and the results of previous PETN shock initiation experiments on single crystals of PETN. Good agreement was obtained for the induction time delays preceding chemical reaction, the run distances at which the initial shock waves were overtaken by the detonation waves in the compressed PETN, and the measured particle velocity histories produced by the overdriven detonation waves before they could relax to steady state C-J velocity and pressure. {copyright} {ital 1997 American Institute of Physics.}« less

Detonation E. O. S. patterns for several explosives

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

Green, L.; Lee, E.L.; Mitchell, A.C.

1983-07-13

The available overdriven shockwave data for a number of explosives have been analyzed and compared. The data follow neither a constant gamma pattern nor the JWL EOS that fits expansion data to high accuracy. Modifications of the JWL function are proposed to correct for discrepancies and also to allow for the appropriate volume dependence of the Grueneisen constant indicated by previous and more recent work. The deviations from the JWL form of the equation of state appear directly above the CJ point for 9404 and PETN while Pentolite and TNT agree with this form over a portion of the Hugoniot.more » The comparisons with other experiments and a theoretical EOS indicate nonequilibrium behavior.« less

Interaction of disturbances with an oblique detonation wave attached to a wedge

NASA Technical Reports Server (NTRS)

Lasseigne, D. G.; Hussaini, M. Y.

1993-01-01

The linear response of an oblique overdriven detonation to impose free stream disturbances or to periodic movements of the wedge is examined. The free stream disturbances are assumed to be steady vorticity waves and the wedge motions are considered to be time periodic oscillations either about a fixed pivot point or along the plane of symmetry of the wedge aligned with the incoming stream. The detonation is considered to be a region of infinitesimal thickness in which a finite amount of heat is released. The response to the imposed disturbances is a function of the Mach number of the incoming flow, the wedge angle, and the exothermocity of the reaction within the detonation. It is shown that as the degree of overdrive increases, the amplitude of the response increases significantly; furthermore, a fundamental difference in the dependence of the response on the parameters of the problem is found between the response to a free stream disturbance and to a disturbance emanating from the wedge surface.

Study of particle evolution from Composition B-3 detonation by time-resolved small angle x-ray scattering

NASA Astrophysics Data System (ADS)

Huber, R.; Podlesak, D.; Dattelbaum, D.; Firestone, M.; Gustavsen, R.; Jensen, B.; Ringstrand, B.; Watkins, E.; Bagge-Hansen, M.; Hodgin, R.; Lauderbach, L.; Willey, T.; van Buuren, T.; Graber, T.; Rigg, P.; Sinclair, N.; Seifert, S.

2017-06-01

High explosive (HE) detonations produce an assortment of gases (CO, CO2, N2) and solid carbon products (nanodiamond, graphite). The evolution of solid carbon particles, within the chemical reaction zone, help to propel the detonation wave forward. Due to the violent nature and short reaction times during HE detonations, experimental observation are limited. Through time-resolved small angle x-ray scattering (TRSAXS) we are able to observed nanocarbon formation on nanosecond time scales. This TRSAXS setup is the first of its kind in the United States at Argonne National Laboratory at the Advanced Photon Source in the Dynamic Compression Sector. From the empirical and analytical analysis of the x-ray scattering of an in-line detonation we are able to temporally follow morphology and size. Two detonation geometries were studied for the HE Comp B-3 (40% TNT/60% RDX), producing steady and overdriven conditions. Steady wave particle evolution plateaued by 2 microseconds, where overdriven condition particle size decreases at the collision of the two shock fronts then plateaus. Post detonation soot is also analyzed to confirm size and shape of nanocarbon formation from Comp B-3 detonations. LA-UR-17-21443.

Apparatus and method for the acceleration of projectiles to hypervelocities

DOEpatents

Hertzberg, Abraham; Bruckner, Adam P.; Bogdanoff, David W.

1990-01-01

A projectile is initially accelerated to a supersonic velocity and then injected into a launch tube filled with a gaseous propellant. The projectile outer surface and launch tube inner surface form a ramjet having a diffuser, a combustion chamber and a nozzle. A catalytic coated flame holder projecting from the projectile ignites the gaseous propellant in the combustion chamber thereby accelerating the projectile in a subsonic combustion mode zone. The projectile then enters an overdriven detonation wave launch tube zone wherein further projectile acceleration is achieved by a formed, controlled overdriven detonation wave capable of igniting the gaseous propellant in the combustion chamber. Ultrahigh velocity projectile accelerations are achieved in a launch tube layered detonation zone having an inner sleeve filled with hydrogen gas. An explosive, which is disposed in the annular zone between the inner sleeve and the launch tube, explodes responsive to an impinging shock wave emanating from the diffuser of the accelerating projectile thereby forcing the inner sleeve inward and imparting an acceleration to the projectile. For applications wherein solid or liquid high explosives are employed, the explosion thereof forces the inner sleeve inward, forming a throat behind the projectile. This throat chokes flow behind, thereby imparting an acceleration to the projectile.

Parametric study of shock-induced combustion in a hydrogen air system

NASA Technical Reports Server (NTRS)

Ahuja, J. K.; Tiwari, Surendra N.

1994-01-01

A numerical parametric study is conducted to simulate shock-induced combustion under various free-stream conditions and varying blunt body diameter. A steady combustion front is established if the free-stream Mach number is above the Chapman-Jouguet speed of the mixture, whereas an unsteady reaction front is established if the free-stream Mach number is below or at the Chapman-Jouguet speed of the mixture. The above two cases have been simulated for Mach 5.11 and Mach 6.46 with a projectile diameter of 15 mm. Mach 5.11, which is an underdriven case, shows an unsteady reaction front, whereas Mach 6.46, which is an overdriven case, shows a steady reaction front. Next for Mach 5. 11 reducing the diameter to 2.5 mm causes the instabilities to disappear, whereas, for Mach 6.46 increasing the diameter of the projectile to 225 mm causes the instabilities to reappear, indicating that Chapman-Jouguet speed is not the only deciding factor for these instabilities to trigger. The other key parameters are the projectile diameter, induction time, activation energy and the heat release. The appearance and disappearance of the instabilities have been explained by the one-dimensional wave interaction model.

Reactive flow modeling of small scale detonation failure experiments for a baseline non-ideal explosive

NASA Astrophysics Data System (ADS)

Kittell, David E.; Cummock, Nick R.; Son, Steven F.

2016-08-01

Small scale characterization experiments using only 1-5 g of a baseline ammonium nitrate plus fuel oil (ANFO) explosive are discussed and simulated using an ignition and growth reactive flow model. There exists a strong need for the small scale characterization of non-ideal explosives in order to adequately survey the wide parameter space in sample composition, density, and microstructure of these materials. However, it is largely unknown in the scientific community whether any useful or meaningful result may be obtained from detonation failure, and whether a minimum sample size or level of confinement exists for the experiments. In this work, it is shown that the parameters of an ignition and growth rate law may be calibrated using the small scale data, which is obtained from a 35 GHz microwave interferometer. Calibration is feasible when the samples are heavily confined and overdriven; this conclusion is supported with detailed simulation output, including pressure and reaction contours inside the ANFO samples. The resulting shock wave velocity is most likely a combined chemical-mechanical response, and simulations of these experiments require an accurate unreacted equation of state (EOS) in addition to the calibrated reaction rate. Other experiments are proposed to gain further insight into the detonation failure data, as well as to help discriminate between the role of the EOS and reaction rate in predicting the measured outcome.

Reactive flow modeling of small scale detonation failure experiments for a baseline non-ideal explosive

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

Kittell, David E.; Cummock, Nick R.; Son, Steven F.

2016-08-14

Small scale characterization experiments using only 1–5 g of a baseline ammonium nitrate plus fuel oil (ANFO) explosive are discussed and simulated using an ignition and growth reactive flow model. There exists a strong need for the small scale characterization of non-ideal explosives in order to adequately survey the wide parameter space in sample composition, density, and microstructure of these materials. However, it is largely unknown in the scientific community whether any useful or meaningful result may be obtained from detonation failure, and whether a minimum sample size or level of confinement exists for the experiments. In this work, itmore » is shown that the parameters of an ignition and growth rate law may be calibrated using the small scale data, which is obtained from a 35 GHz microwave interferometer. Calibration is feasible when the samples are heavily confined and overdriven; this conclusion is supported with detailed simulation output, including pressure and reaction contours inside the ANFO samples. The resulting shock wave velocity is most likely a combined chemical-mechanical response, and simulations of these experiments require an accurate unreacted equation of state (EOS) in addition to the calibrated reaction rate. Other experiments are proposed to gain further insight into the detonation failure data, as well as to help discriminate between the role of the EOS and reaction rate in predicting the measured outcome.« less

Initiation of Insensitive High Explosives Using Multiple Wave Interactions

NASA Astrophysics Data System (ADS)

Francois, Elizabeth; Burritt, Rosmary; Biss, Matt; Bowden, Patrick

2017-06-01

Insensitive High Explosives (IHEs) increase safety in many types of weapons. However, the safety comes at the cost of performance. Initiation of IHE requires large boosters and powerful detonators as well. Multipoint initiation is being utilized to exploit explosive wave interactions to create overdriven states, greatly facilitating the initiation of IHEs. This presentation will build from recent explosive experiments where the minimum spot size for single-point initiation in PBX 9502 was determined. Below this threshold, PBX 9502 could not be initiated. This was then expanded to three initiation points, which were smaller this threshold. Measurements of the velocity and pressure of the wave interactions were measured using Photon Doppler Velocimetry (PDV). Initiation was observed, and the resulting pressures at the double and triple points were found to be above the CJ state for PBX 9502. Based on these results, further tests were conducted to isolate and measure the longevity and pressure of this phenomenon using cut-back tests. All results will be presented and discussed.

Nitromethane ignition observed with embedded PDV optical fibers

NASA Astrophysics Data System (ADS)

Mercier, P.; Bénier, J.; Frugier, P. A.; Debruyne, M.; Crouzet, B.

For a long time, the nitromethane (NM) ignition has been observed with different means such as high-speed cameras, VISAR or optical pyrometry diagnostics. By 2000, David Goosmann (LLNL) studied solid high-explosive detonation and shock loaded metal plates by measuring velocity (Fabry-Pérot interferometry) in embedded optical fibers. For six years Photonic Doppler Velocimetry (PDV) has become a major tool to better understand the phenomena occurring in shock physics experiments. In 2006, we began to use in turn this technique and studied shock-to-detonation transition in NM. Different kinds of bare optical fibers were set in the liquid; they provided two types of velocity information; those coming from phenomena located in front of the fibers (interface velocity, shock waves, overdriven detonation wave) and those due to phenomena environing the fibers (shock or detonation waves). We achieved several shots; devices were composed of a high explosive plane wave generator ended by a metal barrier followed by a cylindrical vessel containing NM. We present results.

The Utility of Gas Gun Experiments in Developing Equations of State

NASA Astrophysics Data System (ADS)

Pittman, Emily; Hagelberg, Carl; Ramsey, Scott

2016-11-01

Gas gun experiments have the potential to investigate material properties in various well defined shock conditions, making them a valuable research tool for the development of equations of state (EOS) and material response under shock loading. Gas guns have the ability to create shocks for loading to pressures ranging from MPa to GPa. A variety of diagnostics techniques can be used to gather data from gas gun experiments; resulting data from these experiments is applicable to many fields of study. The focus of this set of experiments is the development of data on the Hugoniot for the overdriven products EOS of PBX 9501 to extend data from which current computational EOS models draw. This series of shots was conducted by M-9 using the two-stage gas-guns at LANL and aimed to gather data within the 30-120 GPa pressure regime. The experiment was replicated using FLAG, a Langrangian multiphysics code, using a one-dimensional setup which employs the Wescott Stewart Davis (WSD) reactive burn model. Prior to this series, data did not extend into this higher range, so the new data allowed for the model to be re-evaluated. A comparison of the results to the experimental data reveals that the model is a good fit to the data below 40 GPa. However, the model did not fall within the error bars for pressures above this region. This is an indication that the material models or burn model could be modified to better match the data.

Properties of the dead zone due to the gas cushion effect in PBX 9502

NASA Astrophysics Data System (ADS)

Anderson, William

2017-06-01

The gas cushion effect is a well-known phenomenon in which gas trapped between an impactor and an explosive precompresses and deadens a layer of the explosive. We have conducted a series of impact experiments, with and without a trapped gas layer, on the plastic bonded explosive PBX 9502 (95% TATB and 5% Kel-F 800). In each experiment, a 100-oriented LiF window was glued, with an intervening Al foil (a reflector for VISAR), to the surface of a thin (2.5-3.3 mm) PBX 9502 sample and the opposite surface impacted by an impactor at a velocity sufficient to produce an overdriven detonation. VISAR was used to observe arrival of the resulting shock wave and reverberations between the LiF window and the impactor. In three experiments, a gap of 25-38 mm, filled with He gas at a pressure of 0.79 bar, existed between the impactor and the sample at the beginning of the experiment. In these three experiments, a low-amplitude wave reflected from the interface between the reacted explosive and the dead zone was observed to precede the reflection from the impactor. We have used the observed wave amplitudes and arrival times to quantify the properties of the dead zone and, by comparison to existing EOS data for reacted and unreacted PBX 9502, estimate the extent of reaction in the dead zone. This work was supported by the US Department of Energy under contract DE-AC52-06NA25396.

High-power LED light sources for optical measurement systems operated in continuous and overdriven pulsed modes

NASA Astrophysics Data System (ADS)

Stasicki, Bolesław; Schröder, Andreas; Boden, Fritz; Ludwikowski, Krzysztof

2017-06-01

The rapid progress of light emitting diode (LED) technology has recently resulted in the availability of high power devices with unprecedented light emission intensities comparable to those of visible laser light sources. On this basis two versatile devices have been developed, constructed and tested. The first one is a high-power, single-LED illuminator equipped with exchangeable projection lenses providing a homogenous light spot of defined diameter. The second device is a multi-LED illuminator array consisting of a number of high-power LEDs, each integrated with a separate collimating lens. These devices can emit R, G, CG, B, UV or white light and can be operated in pulsed or continuous wave (CW) mode. Using an external trigger signal they can be easily synchronized with cameras or other devices. The mode of operation and all parameters can be controlled by software. Various experiments have shown that these devices have become a versatile and competitive alternative to laser and xenon lamp based light sources. The principle, design, achieved performances and application examples are given in this paper.

Revisiting Shock Initiation Modeling of Homogeneous Explosives

NASA Astrophysics Data System (ADS)

Partom, Yehuda

2013-04-01

Shock initiation of homogeneous explosives has been a subject of research since the 1960s, with neat and sensitized nitromethane as the main materials for experiments. A shock initiation model of homogeneous explosives was established in the early 1960s. It involves a thermal explosion event at the shock entrance boundary, which develops into a superdetonation that overtakes the initial shock. In recent years, Sheffield and his group, using accurate experimental tools, were able to observe details of buildup of the superdetonation. There are many papers on modeling shock initiation of heterogeneous explosives, but there are only a few papers on modeling shock initiation of homogeneous explosives. In this article, bulk reaction reactive flow equations are used to model homogeneous shock initiation in an attempt to reproduce experimental data of Sheffield and his group. It was possible to reproduce the main features of the shock initiation process, including thermal explosion, superdetonation, input shock overtake, overdriven detonation after overtake, and the beginning of decay toward Chapman-Jouget (CJ) detonation. The time to overtake (TTO) as function of input pressure was also calculated and compared to the experimental TTO.

The shock sensitivity of nitromethane/methanol mixtures

NASA Astrophysics Data System (ADS)

Bartram, Brian; Dattelbaum, Dana; Sheffield, Steve; Gibson, Lee

2013-06-01

The dilution of liquid explosives has multiple effects on detonation properties including an increase in critical diameter, spatiotemporal lengthening of the chemical reaction zone, and the development of propagating wave instabilities. Earlier detonation studies of NM/methanol mixtures have shown several effects of increasing dilution, including: 1) a continual increase in the critical diameter, 2) lowering of the Chapman-Jouguet detonation pressure, and 3) slowing of the steady detonation velocity (Koldunov et al., Comb. Expl. Shock Waves). Here, we present the results of a series of gas gun-driven plate-impact experiments to study the shock-to-detonation transition in NM/methanol mixtures. Embedded electromagnetic gauges were used to obtain in situ particle velocity wave profiles at multiple Lagrangian positions in the initiating explosive mixture. From the wave profiles obtained in each experiment, an unreacted Hugoniot locus, the initiation mechanism, and the overtake-time-to-detonation were obtained as a function of shock input condition for mixture concentrations from 100% NM to 50 wt%/50 wt% NM/methanol. Desensitization with dilution is less than expected. For example, little change in overtake time occurs in 80 wt%/20 wt% NM/methanol when compared with neat NM. Furthermore, the shock wave profiles from the gauges indicate that wave instabilities grow in as the overdriven detonation wave settles down following the shock-to-detonation transition.

Weakly nonlinear dynamics of near-CJ detonation waves

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

Bdzil, J.B.; Klein, R.

1993-01-01

The renewed interest in safety issues for large scale industrial devices and in high speed combustion has driven recent intense efforts to gain a deeper theoretical understanding of detonation wave dynamics. Linear stability analyses, weakly nonlinear bifurcation calculations as well as full scale multi-dimensional direct numerical simulations have been pursued for a standard model problem based on the reactive Euler equations for an ideal gas with constant specific heat capacities and simplified chemical reaction models. Most of these studies are concerned with overdriven detonations. This is true despite the fact that the majority of all detonations observed in nature aremore » running at speeds close to the Chapman-Jouguet (CJ) limit value. By focusing on overdriven waves one removes an array of difficulties from the analysis that is associated with the sonic flow conditions in the wake of a CJ-detonation. In particular, the proper formulation of downstream boundary conditions in the CJ-case is a yet unsolved analytical problem. A proper treatment of perturbations in the back of a Chapman-Jouguet detonation has to account for two distinct weakly nonlinear effects in the forward acoustic wave component. The first is a nonlinear interactionof highly temperature sensitive chemistry with the forward acoustic wave component in a transonic boundary layer near the end of the reaction zone. The second is a cumulative three-wave-resonance in the sense of Majda et al. which is active in the near-sonic burnt gas flow and which is essentially independent of the details of the chemical model. In this work, we consider detonations in mixtures with moderate state sensitivity of the chemical reactions. Then, the acoustic perturbations do not influence the chemistry at the order considered and we may concentrate on the second effect; the three-wave resonance.« less

Weakly nonlinear dynamics of near-CJ detonation waves

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

Bdzil, J.B.; Klein, R.

1993-02-01

The renewed interest in safety issues for large scale industrial devices and in high speed combustion has driven recent intense efforts to gain a deeper theoretical understanding of detonation wave dynamics. Linear stability analyses, weakly nonlinear bifurcation calculations as well as full scale multi-dimensional direct numerical simulations have been pursued for a standard model problem based on the reactive Euler equations for an ideal gas with constant specific heat capacities and simplified chemical reaction models. Most of these studies are concerned with overdriven detonations. This is true despite the fact that the majority of all detonations observed in nature aremore » running at speeds close to the Chapman-Jouguet (CJ) limit value. By focusing on overdriven waves one removes an array of difficulties from the analysis that is associated with the sonic flow conditions in the wake of a CJ-detonation. In particular, the proper formulation of downstream boundary conditions in the CJ-case is a yet unsolved analytical problem. A proper treatment of perturbations in the back of a Chapman-Jouguet detonation has to account for two distinct weakly nonlinear effects in the forward acoustic wave component. The first is a nonlinear interactionof highly temperature sensitive chemistry with the forward acoustic wave component in a transonic boundary layer near the end of the reaction zone. The second is a cumulative three-wave-resonance in the sense of Majda et al. which is active in the near-sonic burnt gas flow and which is essentially independent of the details of the chemical model. In this work, we consider detonations in mixtures with moderate state sensitivity of the chemical reactions. Then, the acoustic perturbations do not influence the chemistry at the order considered and we may concentrate on the second effect; the three-wave resonance.« less

Numerical simulations of detonation propagation in gaseous fuel-air mixtures

NASA Astrophysics Data System (ADS)

Honhar, Praveen; Kaplan, Carolyn; Houim, Ryan; Oran, Elaine

2017-11-01

Unsteady multidimensional numerical simulations of detonation propagation and survival in mixtures of fuel (hydrogen or methane) diluted with air were carried out with a fully compressible Navier-Stokes solver using a simplified chemical-diffusive model (CDM). The CDM was derived using a genetic algorithm combined with the Nelder-Mead optimization algorithm and reproduces physically correct laminar flame and detonation properties. Cases studied are overdriven detonations propagating through confined mediums, with or without gradients in composition. Results from simulations confirm that the survival of the detonation depends on the channel heights. In addition, the simulations show that the propagation of the detonation waves depends on the steepness in composition gradients.

Predicting propagation limits of laser-supported detonation by Hugoniot analysis

NASA Astrophysics Data System (ADS)

Shimamura, Kohei; Ofosu, Joseph A.; Komurasaki, Kimiya; Koizumi, Hiroyuki

2015-01-01

Termination conditions of a laser-supported detonation (LSD) wave were investigated using control volume analysis with a Shimada-Hugoniot curve and a Rayleigh line. Because the geometric configurations strongly affect the termination condition, a rectangular tube was used to create the quasi-one-dimensional configuration. The LSD wave propagation velocity and the pressure behind LSD were measured. Results reveal that the detonation states during detonation and at the propagation limit are overdriven detonation and Chapman-Jouguet detonation, respectively. The termination condition is the minimum velocity criterion for the possible detonation solution. Results were verified using pressure measurements of the stagnation pressure behind the LSD wave.

Nitrogen-rich heterocycles as reactivity retardants in shocked insensitive explosives.

PubMed

Manaa, M Riad; Reed, Evan J; Fried, Laurence E; Goldman, Nir

2009-04-22

We report the first quantum-based multiscale simulations to study the reactivity of shocked perfect crystals of the insensitive energetic material triaminotrinitrobenzene (TATB). Tracking chemical transformations of TATB experiencing overdriven shock speeds of 9 km/s for up to 0.43 ns and 10 km/s for up to 0.2 ns reveal high concentrations of nitrogen-rich heterocyclic clusters. Further reactivity of TATB toward the final decomposition products of fluid N(2) and solid carbon is inhibited due to the formation of these heterocycles. Our results thus suggest a new mechanism for carbon-rich explosive materials that precedes the slow diffusion-limited process of forming the bulk solid from carbon clusters and provide fundamental insight at the atomistic level into the long reaction zone of shocked TATB.

Non-linear interaction of a detonation/vorticity wave

NASA Technical Reports Server (NTRS)

Lasseigne, D. G.; Jackson, T. L.; Hussaini, M. Y.

1991-01-01

The interaction of an oblique, overdriven detonation wave with a vorticity disturbance is investigated by a direct two-dimensional numerical simulation using a multi-domain, finite-difference solution of the compressible Euler equations. The results are compared to those of linear theory, which predict that the effect of exothermicity on the interaction is relatively small except possibly near a critical angle where linear theory no longer holds. It is found that the steady-state computational results agree with the results of linear theory. However, for cases with incident angle near the critical angle, moderate disturbance amplitudes, and/or sudden transient encounter with a disturbance, the effects of exothermicity are more pronounced than predicted by linear theory. Finally, it is found that linear theory correctly determines the critical angle.

A High Efficiency Multiple-Anode 260-340 GHz Frequency Tripler

NASA Technical Reports Server (NTRS)

Maestrini, Alain; Tripon-Canseliet, Charlotte; Ward, John S.; Gill, John J.; Mehdi, Imran

2006-01-01

We report on the fabrication at the Jet Propulsion Laboratory of a fixed-tuned split-block waveguide balanced frequency tripler working in the 260-340 GHz band. This tripler will be the first stage of a x3x3x3 multiplier chain to 2.7 THz (the last stages of which are being fabricated at JPL) and is therefore optimized for high power operation. The multiplier features six GaAs Schottky planar diodes in a balanced configuration integrated on a GaAs membrane. Special attention was put on splitting the input power as evenly as possible among the diodes in order to ensure that no diode is overdriven. Preliminary RF tests indicate that the multiplier covers the expected bandwidth and that the efficiency is in the range 1.5-7.5 % with 100 mW of input power.

Accuracy and Calibration of High Explosive Thermodynamic Equations of State

NASA Astrophysics Data System (ADS)

Baker, Ernest L.; Capellos, Christos; Stiel, Leonard I.; Pincay, Jack

2010-10-01

The Jones-Wilkins-Lee-Baker (JWLB) equation of state (EOS) was developed to more accurately describe overdriven detonation while maintaining an accurate description of high explosive products expansion work output. The increased mathematical complexity of the JWLB high explosive equations of state provides increased accuracy for practical problems of interest. Increased numbers of parameters are often justified based on improved physics descriptions but can also mean increased calibration complexity. A generalized extent of aluminum reaction Jones-Wilkins-Lee (JWL)-based EOS was developed in order to more accurately describe the observed behavior of aluminized explosives detonation products expansion. A calibration method was developed to describe the unreacted, partially reacted, and completely reacted explosive using nonlinear optimization. A reasonable calibration of a generalized extent of aluminum reaction JWLB EOS as a function of aluminum reaction fraction has not yet been achieved due to the increased mathematical complexity of the JWLB form.

An Integrated Gate Driver in 4H-SiC for Power Converter Applications

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

Ericson, Milton Nance; Frank, Steven Shane; Britton, Charles

2014-01-01

A gate driver fabricated in a 2-um 4H silicon carbide (SiC) process is presented. This process was optimized for vertical power MOSFET fabrication but accommodated integration of a few low-voltage device types including N-channel MOSFETs, resistors, and capacitors. The gate driver topology employed incorporates an input level translator, variable power connections, and separate power supply connectivity allowing selection of the output signal drive amplitude. The output stage utilizes a source follower pull-up device that is both overdriven and body source connected to improve rise time behavior. Full characterization of this design driving a SiC power MOSFET is presented including risemore » and fall times, propagation delays, and power consumption. All parameters were measured to elevated temperatures exceeding 300 C. Details of the custom test system hardware and software utilized for gate driver testing are also provided.« less

Current and efficiency optimization under oscillating forces in entropic barriers

NASA Astrophysics Data System (ADS)

Nutku, Ferhat; Aydıner, Ekrem

2016-09-01

The transport of externally overdriven particles confined in entropic barriers is investigated under various types of oscillating and temporal forces. Temperature, load, and amplitude dependence of the particle current and energy conversion efficiency are investigated in three dimensions. For oscillating forces, the optimized temperature-load, amplitude-temperature, and amplitude-load intervals are determined when fixing the amplitude, load, and temperature, respectively. By using three-dimensional plots rather than two-dimensional ones, it is clearly shown that oscillating forces provide more efficiency compared with a temporal one in specified optimized parameter regions. Furthermore, the dependency of efficiency to the angle between the unbiased driving force and a constant force is investigated and an asymmetric angular dependence is found for all types of forces. Finally, it is shown that oscillating forces with a high amplitude and under a moderate load lead to higher efficiencies than a temporal force at both low and high temperatures for the entire range of contact angle. Project supported by the Istanbul University, Turkey (Grant No. 55383).

Determination of the long-term release of metal(loid)s from construction materials using DGTs.

PubMed

Schmukat, A; Duester, L; Ecker, D; Heininger, P; Ternes, T A

2013-09-15

Long-term leaching experiments are crucial to estimate the potential release of dangerous substances from construction materials. The application of Diffuse Gradients in Thin film (DGT) in static-batch experiments was tested to study the long-term release of metal(loid)s from construction materials for hydraulic engineering, for half a year. Long-term release experiments are essential to improve calculations of the life-time release for this materials. DGTs in batch experiments were found to be a space and labour efficient application, which enabled (i) to study, in a non-invasive manner, the total release of nine metal(loid)s for half a year, (ii) to differentiate between release mechanisms and (iii) to study mechanisms which were contrary to the release or caused experimental artefacts in the batch experiments. For copper slag (test material) it was found that eight metal(loid)s were released over the whole time period of 184 d. Cu, Ni and Pb were found to be released, predominantly caused by (the) weathering of sulphide minerals. Only for Zn a surface depletion mechanism was identified. The results from the long-term batch experiments deliver new information on the release of metal(loid)s during the life cycle of construction materials with regard to river basin management objectives. Copyright © 2013 Elsevier B.V. All rights reserved.

On the propagation mechanism of a detonation wave in a round tube with orifice plates

NASA Astrophysics Data System (ADS)

Ciccarelli, G.; Cross, M.

2016-09-01

This study deals with the investigation of the detonation propagation mechanism in a circular tube with orifice plates. Experiments were performed with hydrogen air in a 10-cm-inner-diameter tube with the second half of the tube filled with equally spaced orifice plates. A self-sustained Chapman-Jouguet (CJ) detonation wave was initiated in the smooth first half of the tube and transmitted into the orifice-plate-laden second half of the tube. The details of the propagation were obtained using the soot-foil technique. Two types of foils were used between obstacles, a wall-foil placed on the tube wall, and a flat-foil (sooted on both sides) placed horizontally across the diameter of the tube. When placed after the first orifice plate, the flat foil shows symmetric detonation wave diffraction and failure, while the wall foil shows re-initiation via multiple local hot spots created when the decoupled shock wave interacts with the tube wall. At the end of the tube, where the detonation propagated at an average velocity much lower than the theoretical CJ value, the detonation propagation is much more asymmetric with only a few hot spots on the tube wall leading to local detonation initiation. Consecutive foils also show that the detonation structure changes after each obstacle interaction. For a mixture near the detonation propagation limit, detonation re-initiation occurs at a single wall hot spot producing a patch of small detonation cells. The local overdriven detonation wave is short lived, but is sufficient to keep the global explosion front propagating. Results associated with the effect of orifice plate blockage and spacing on the detonation propagation mechanism are also presented.

Theory, Image Simulation, and Data Analysis of Chemical Release Experiments

NASA Technical Reports Server (NTRS)

Wescott, Eugene M.

1994-01-01

The final phase of Grant NAG6-1 involved analysis of physics of chemical releases in the upper atmosphere and analysis of data obtained on previous NASA sponsored chemical release rocket experiments. Several lines of investigation of past chemical release experiments and computer simulations have been proceeding in parallel. This report summarizes the work performed and the resulting publications. The following topics are addressed: analysis of the 1987 Greenland rocket experiments; calculation of emission rates for barium, strontium, and calcium; the CRIT 1 and 2 experiments (Collisional Ionization Cross Section experiments); image calibration using background stars; rapid ray motions in ionospheric plasma clouds; and the NOONCUSP rocket experiments.

The Combined Release and Radiation Effects Satellite (CRRES) program: A unique series of scientific experiments

NASA Technical Reports Server (NTRS)

Reasoner, David L.; Mccook, Morgan W. (Editor); Vaughan, William W. (Editor)

1990-01-01

The Defense Department and NASA have joined in a program to study the space environment which surrounds the earth and the effects of space radiation on modern satellite electronic systems. The Combined Release and Radiation Effects Satellite (CRRES) will carry an array of active experiments including chemical releases and a complement of sophisticated scientific instruments to accomplish these objectives. Other chemical release active experiments will be performed with sub-orbital rocket probes. The chemical releases will 'paint' the magnetic and electric fields of earthspace with clouds of glowing ions. Earthspace will be a laboratory, and the releases will be studied with an extensive network of ground-, aircraft-, and satellite-based diagnostic instruments. Some of the topics discussed include the following: the effects of earthspace; the need for active experiments; types of chemical releases; the CRRES program schedule; international support and coordinated studies; photographing chemical releases; information on locating chemical releases for observation by the amateur; and CRRES as a program.

The Combined Release and Radiation Effects Satellite (CRRES) program: A unique series of scientific experiments

NASA Astrophysics Data System (ADS)

Reasoner, David L.; McCook, Morgan W.; Vaughan, William W.

The Defense Department and NASA have joined in a program to study the space environment which surrounds the earth and the effects of space radiation on modern satellite electronic systems. The Combined Release and Radiation Effects Satellite (CRRES) will carry an array of active experiments including chemical releases and a complement of sophisticated scientific instruments to accomplish these objectives. Other chemical release active experiments will be performed with sub-orbital rocket probes. The chemical releases will 'paint' the magnetic and electric fields of earthspace with clouds of glowing ions. Earthspace will be a laboratory, and the releases will be studied with an extensive network of ground-, aircraft-, and satellite-based diagnostic instruments. Some of the topics discussed include the following: the effects of earthspace; the need for active experiments; types of chemical releases; the CRRES program schedule; international support and coordinated studies; photographing chemical releases; information on locating chemical releases for observation by the amateur; and CRRES as a program.

Social support among releasing men prisoners with lifetime trauma experiences.

PubMed

Pettus-Davis, Carrie

2014-01-01

High rates of lifetime trauma experiences exist among men incarcerated in US state and federal prisons. Because lifetime trauma experiences have been linked to problematic behavioral and psychiatric outcomes for incarcerated populations, trauma-informed interventions could improve post-release well-being of releasing men prisoners with trauma histories. Social support has consistently been found to have a positive impact on trauma-related outcomes in non-incarcerated populations. Therefore, it is reasonable to hypothesize that social support may be an important intervention component for releasing men prisoners with trauma experiences; yet, the relationship between trauma experiences, psychiatric and behavioral factors, and social support has received almost no attention in research with men prisoners. Using a probability sample of 165 soon-to-be-released men, the present study examined differences in certain demographic, criminal justice history, mental health, substance abuse, and social support (type, quality, amount, and source) variables between releasing men prisoners with and without lifetime trauma experiences. Results indicate that men with trauma histories had more negative social support experiences and fewer positive social support resources before prison than their counterparts. Men with trauma histories also had more lifetime experiences with mental health and substance use problems. On further investigation of the subsample of men with trauma histories, those who were older, had substance use disorders, and histories of mental health problems anticipated fewer post-release social support resources. Study findings underscore the nuances of social support for men prisoners with trauma experiences and point to implications for future directions in targeted trauma-informed intervention development for releasing men prisoners. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quasi-isentropic Compression of Iron and Magnesium Oxide to 3 Mbar at the Omega Laser Facility

NASA Astrophysics Data System (ADS)

Wang, J.; Smith, R. F.; Coppari, F.; Eggert, J. H.; Boehly, T.; Collins, G.; Duffy, T. S.

2011-12-01

Developing a high-pressure, modest temperature ramp compression drive permits exploration of new regions of thermodynamic space, inaccessible through traditional methods of shock or static compression, and of particular relevance to material conditions found in planetary interiors both within and outside our solar system. Ramp compression is a developing technique that allows materials to be compressed along a quasi-isentropic path and provides the ability to study materials in the solid state to higher pressures than can be achieved with diamond anvil cell or shock wave methods. Iron and magnesium oxide are geologically important materials each representative of one of the two major interior regions (core and mantle) of terrestrial planets. An experimental platform for ramp loading of iron (Fe) and magnesium oxide (MgO), has been established and tested in experiments at the Omega Laser Facility, University of Rochester. Omega is a 60-beam ultraviolet (352 nm) neodymium glass laser which is capable of delivery kilojoules of energy in ~10 ns pulses onto targets of a few mm in dimension. In the current experiments, we used a composite ramped laser pulse involving typically 15 beams with total energy of 2.6-3.3 kJ. The laser beams were used to launch spatially planar ramp compression waves into Fe and MgO targets. Each target had four steps that were approximately 5-7 μm thick. Detection of the ramp wave arrival and its velocity at the free surface of each step was made using a VISAR velocity interferometer. Through the use of Lagrangian analysis on the measured wave profiles, stress-density states in iron and magnesium oxide have been determined to pressures of 291 GPa and 260 GPa respectively. For Fe, the α-ɛ transition of iron is overdriven by an initial shock pulse of ~90.1 GPa followed by ramp compression to the peak pressure. The results will be compared with shock compression and diamond anvil cell data for both materials.

We acknowledge the Omega staff at LLE for their assistance, Micro/Nano fabrication laboratory staff at Princeton University and the Target Engineering Team at LLNL for fabrication and metrology of the targets used in these experiments. The research was supported by DOE under DE-FG52-09NA29037.

Release mechanism for releasing and reattaching experiments on the Space Shuttle

NASA Technical Reports Server (NTRS)

Clark, A. V.

1980-01-01

The release mechanism (REM) unlatches an experiment so that it can be moved about inside and outside the shuttle bay by the remote manipulator system (RMS), and then reattaches it to the REM base. Operated from the crew compartment after the RMS has been attached to the experiment, the REM releases the experiment by an electric motor driving a gear train and linkage which extracts four pins from holes in four plates. Electrical connectors on the REM are disengaged by the mechanical action of the structural pins retracting from the plates. When the REM releases the experiment, an unlatched indicator is actuated in the crew compartment, and then the experiment can be moved by using the RMS. To reattach the experiment to the REM, the RMS places the experiment with REM attachment angles against the flat, smooth surface of the REM; then the RMS moves the experiment into position for latchup. Actuation of an electric motor drives the four pins into the four holes in the plates. When fully latched, a switch actuated by the motion of the linkage, shuts the electric motor off and gives an indication to the crew compartment that the REM is latched.

The Combined Release and Radiation Effects Satellite program (CRRES): A unique series of scientific experiments

NASA Technical Reports Server (NTRS)

1991-01-01

CRRES is a program to study the space environment which surrounds Earth and the effects of space radiation on modern satellite electronic systems. The satellite will carry an array of active experiments including chemical releases and a complement of sophisticated scientific instruments to accomplish these objectives. Other chemical release active experiments will be performed with suborbital rocket probes. These chemical releases will paint the magnetic and electric fields in Earthspace with clouds of glowing ions. Earthspace will be a laboratory, and the releases will be studied with an extensive network of ground-, aircraft-, and satellite-based diagnostic instruments.

Optimum performance of explosives in a quasistatic detonation cycle

NASA Astrophysics Data System (ADS)

Baker, Ernest L.; Stiel, Leonard I.

2017-01-01

Analyses were conducted on the behavior of explosives in a quasistatic detonation cycle. This type of cycle has been proposed for the determination of the maximum work that can be performed by the explosive. The Jaguar thermochemical equilibrium program enabled the direct analyses of explosive performance at the various steps in the detonation cycle. In all cases the explosive is initially detonated to a point on the Hugoniot curve for the reaction products. The maximum useful work that can be obtained from the explosive is equal to the P-V work on the isentrope for expansion after detonation to atmospheric pressure, minus one-half the square of the particle velocity at the detonation point. This quantity is calculated form the internal energy of the explosive at the initial and final atmospheric temperatures. Cycle efficiencies (net work/ heat added) are also calculated with these procedures. For several explosives including TNT, RDX, and aluminized compositions, maximum work effects were established through the Jaguar calculations for Hugoniot points corresponding to C-J, overdriven, underdriven and constant volume detonations. Detonation to the C-J point is found to result in the maximum net work in all cases.

Mirrored continuum and molecular scale simulations of the ignition of gamma phase RDX

NASA Astrophysics Data System (ADS)

Stewart, D. Scott; Chaudhuri, Santanu; Joshi, Kaushik; Lee, Kiabek

2015-06-01

We consider the ignition of a high-pressure gamma-phase of an explosive crystal of RDX which forms during overdriven shock initiation. Molecular dynamics (MD), with first-principles based or reactive force field based molecular potentials, provides a description of the chemistry as an extremely complex reaction network. The results of the molecular simulation is analyzed by sorting molecular product fragments into high and low molecular groups, to represent identifiable components that can be interpreted by a continuum model. A continuum model based on a Gibbs formulation, that has a single temperature and stress state for the mixture is used to represent the same RDX material and its chemistry. Each component in the continuum model has a corresponding Gibbs continuum potential, that are in turn inferred from molecular MD informed equation of state libraries such as CHEETAH, or are directly simulated by Monte Carlo MD simulations. Information about transport, kinetic rates and diffusion are derived from the MD simulation and the growth of a reactive hot spot in the RDX is studied with both simulations that mirror the other results to provide an essential, continuum/atomistic link. Supported by N000014-12-1-0555, subaward-36561937 (ONR).

Sexually stimulated testosterone release in male mice (Mus musculus): roles of genotype and sexual arousal.

PubMed

James, Peter J; Nyby, John G; Saviolakis, George A

2006-09-01

In virtually every mammalian species examined, some males exhibit reflexive testosterone release upon encountering a novel female (or female-related stimulus). At the same time, not every individual male (or every published study) provides evidence for reflexive testosterone release. Four experiments using house mice (Mus musculus) examined the hypothesis that both the male's genotype and his degree of sexual arousal (as indexed by ultrasonic mating calls) are related to such variability. In Experiment 1, CF-1 males exhibited reflexive testosterone elevations 30 min after encountering female urine. CK males, on the other hand, did not exhibit testosterone elevations 20, 30, 50, 60, or 80 min after encountering female urine (Experiments 1 and 2) suggesting this strain incapable of reflexive release. In Experiment 3, we measured both mating calls and reflexive testosterone release in response to female urine in CF-1 and CK males. Most males of both strains called vigorously to female urine but not to water. But, only CF-1 males exhibited significant testosterone elevations to female urine. In Experiment 4, DBA/2J males called vigorously to females followed by testosterone elevations 30 min later. The first 3 experiments support the hypothesis that male genotype is an important variable underlying mammalian reflexive testosterone release. Statistically significant correlations between mating calls in the first minute after stimulus exposure and testosterone elevations 30 min later (Experiments 3 and 4) support the hypothesis that, in capable males, reflexive testosterone release is related to the male's initial sexual arousal.

Injectable Silica–Permanganate Gel as a Slow-Release MnO 4 - Source for Groundwater Remediation. Rheological Properties and Release Dynamics

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

Yang, Shuo; Oostrom, Martinus; Truex, Michael J.

2016-01-12

Injectable slow-release permanganate gel (ISRPG), formed by mixing KMnO 4 solution with fumed silica powder, may have a potential application in remediating chlorinated solvent plumes in groundwater. A series of batch, column, and flow cell experiments has been completed to test the gel behavior under a variety of conditions. The experiments have provided information on ISRPG rheology, permanganate (MnO 4 - ) release dynamics and distribution, and trichloroethene (TCE) degradation by ISRPG-released oxidant. The gel possesses remarkable shear thinning characteristics, resulting in a relative low viscosity during mixing, and facilitating its subsurface injection and distribution. Batch tests revealed that MnOmore » 4 - was diffused out from ISRPG into water while the gel did not dissolve or disperse into water but maintained its initial shape. Column experiments showed that MnO 4 - release from ISRPG lasted considerably longer than the release from aqueous solution. TCE degradation by ISRPG-released MnO 4 - was much more effective than that when MnO 4 - was delivered using aqueous solution injection. In two-dimensional flow cell experiments, it was demonstrated that ISRPG slowly released a long-lasting low concentration MnO 4 - plume sufficient for remediation and sustainable in an aquifer for a long period of time.« less

Reducing the Use of Agrochemicals: A Simple Experiment

ERIC Educational Resources Information Center

Vidal, M. M.; Filipe, Olga M. S.; Costa, M. C. Cruz

2006-01-01

An experiment was performed on polymeric-based controlled-release agrochemicals that minimize leaching into groundwater while maintaining an adequate quantity for the desired agrochemical benefits. Gelatin gel containing inorganic Phosphorous provides controlled-release of an agrochemical where release curves show a linear relationship between…

CRRES: Combined Release and Radiation Effects Satellite Program Summary

NASA Technical Reports Server (NTRS)

Layman, Laura D.; Miller, George P.

1993-01-01

The experiments that comprise the Combined Release and Radiation Effects Satellite Program (CRRES) (Apr. 1990 - Jul. 1992) are presented. The experiments are as follows: PEGSAT; El Coqui; the Kwajalein Campaign; and experiments G1 - G14.

Radar investigation of barium releases over Arecibo Observatory, Puerto Rico

NASA Technical Reports Server (NTRS)

Djuth, Frank T.

1995-01-01

The NASA Combined Release and Radiation Effects Satellite (CRRES) El Coqui rocket campaign was successfully carried out in Puerto Rico during the period 18 May through 12 July 1992. This report describes five chemical release experiments in the upper ionosphere supported by Geospace Research, Inc. during the El Coqui campaign. Additional spin-off science is also discussed. The El Coqui releases are designated AA-1 (rocket 36-082), AA-2 (rocket 36-081), AA-3b (rocket 36-064), AA-4 (rocket 36-065), and AA-7 (rocket 36-083). Particular attention is paid to releases AA-2 and AA-4. These two experiments involved the illumination of ionospheric release regions with powerful high-frequency (HF) radio waves transmitted from the Arecibo HF facility. In the AA-2 experiment, microinstabilities excited by the HF wave in a Ba(+) plasma were examined. This release yielded a smooth plasma cloud that helped clarify several fundamental issues regarding the physics of wave plasma instabilities. During AA-2 extremely strong HF-induced Langmuir turbulence was detected with the Arecibo 430 MHz radar. CF3Br was released in the AA-4 study to create an ionospheric hole that focused the HF beam. This experiment successfully explored wave-plasma coupling in an O(+) ionosphere under conditions of very high HF electric field strengths.

Studies related to the development of the Viking 1975 labeled release experiment

NASA Technical Reports Server (NTRS)

Devincenzi, D. L.; Deal, P. H.

1976-01-01

The labeled release life detection experiment on the Viking 1975 Mars mission is based on the concept that microorganisms will metabolize radioactive organic substrates in a nutrient medium and release radioactive carbon dioxide. Several experiments, using laboratory equipment, were carried out to evaluate various aspects of the concept. Results indicate: (1) label is released by sterilization-treated soil, (2) substantial quantities of label are retained in solution under basic conditions, (3) the substrate used, as well as position of label in the molecule, affect release of label, (4) label release is depressed by radiolytic decomposition of substrates, and (5) About 100,000 organisms are required to produce a detectable response. These results, suggest additional areas for testing, add to the data base for interpretation of flight results, and have significance for broader application of this technique for assessing microbial activity.

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

NASA Technical Reports Server (NTRS)

Long, Terry N.; Alzmann, Melanie O.

1992-01-01

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

Shock, release and reshock of PBX 9502: experiments and modeling

NASA Astrophysics Data System (ADS)

Aslam, Tariq; Gustavsen, Richard; Whitworh, Nicholas; Menikoff, Ralph; Tarver, Craig; Handley, Caroline; Bartram, Brian

2017-06-01

We examine shock, release and reshock into the tri-amino-tri-nitro-benzene (TATB) based explosive PBX 9502 (95% TATB, 5% Kel-F 800) from both an experimental and modeling point of view. The experiments are performed on the 2-stage light gas gun at Los Alamos National Laboratory and are composed of a multi-layered impactor impinging on PBX 9502 backed by a polymethylmethacrylate window. The objective is to initially shock the PBX 9502 in the 7 GPa range (too weak to start significant reaction), then allow a rarefaction fan to release the material to a lower pressure/temperature state. Following this release, a strong second shock will recompress the PBX. If the rarefaction fan releases the PBX to a very low pressure, the ensuing second shock can increase the entropy and temperature substantially more than in previous double-shock experiments without an intermediate release. Predictions from a variety of reactive burn models (AWSD, CREST, Ignition and Growth, SURF) demonstrate significantly different behaviors and thus the experiments are an excellent validation test of the models, and may suggest improvements for subsequent modeling efforts.

Lake Roosevelt Fisheries Evaluation Program : Lake Whatcom Kokanee Salmon (Oncorhynchus nerka kennerlyi) : Investigations in Lake Roosevelt Annual Report 1999-2000.

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

McLellan, Holly J.; Scholz, Allan T.; McLellan, Jason G.

2001-07-01

Lake Whatcom stock kokanee have been planted in Lake Roosevelt since 1988 with the primary goal of establishing a self-sustaining fishery. Returns of hatchery kokanee to egg collection facilities and recruitment to the creel have been minimal. Therefore, four experiments were conducted to determine the most appropriate release strategy that would increase kokanee returns. The first experiment compared morpholine and non-morpholine imprinted kokanee return rates, the second experiment compared early and middle run Whatcom kokanee, the third experiment compared early and late release dates, and the fourth experiment compared three net pen release strategies: Sherman Creek hatchery vs. Sherman Creekmore » net pens, Colville River net pens vs. Sherman Creek net pens, and upper vs. lower reservoir net pen releases. Each experiment was tested in three ways: (1) returns to Sherman Creek, (2) returns to other tributaries throughout the reservoir, and (3) returns to the creel. Chi-square analysis of hatchery and tributary returns indicated no significant difference between morpholine imprinted and non-imprinted fish, early run fish outperformed middle run fish, early release date outperformed late release fish, and the hatchery outperformed all net pen releases. Hatchery kokanee harvest was estimated at 3,323 fish, which was 33% of the total harvest. Return rates (1998 = 0.52%) of Whatcom kokanee were low indicating an overall low performance that could be caused by high entrainment, predation, and precocity. A kokanee stock native to the upper Columbia, as opposed to the coastal Whatcom stock, may perform better in Lake Roosevelt.« less

Interaural level differences do not suffice for restoring spatial release from masking in simulated cochlear implant listening.

PubMed

Ihlefeld, Antje; Litovsky, Ruth Y

2012-01-01

Spatial release from masking refers to a benefit for speech understanding. It occurs when a target talker and a masker talker are spatially separated. In those cases, speech intelligibility for target speech is typically higher than when both talkers are at the same location. In cochlear implant listeners, spatial release from masking is much reduced or absent compared with normal hearing listeners. Perhaps this reduced spatial release occurs because cochlear implant listeners cannot effectively attend to spatial cues. Three experiments examined factors that may interfere with deploying spatial attention to a target talker masked by another talker. To simulate cochlear implant listening, stimuli were vocoded with two unique features. First, we used 50-Hz low-pass filtered speech envelopes and noise carriers, strongly reducing the possibility of temporal pitch cues; second, co-modulation was imposed on target and masker utterances to enhance perceptual fusion between the two sources. Stimuli were presented over headphones. Experiments 1 and 2 presented high-fidelity spatial cues with unprocessed and vocoded speech. Experiment 3 maintained faithful long-term average interaural level differences but presented scrambled interaural time differences with vocoded speech. Results show a robust spatial release from masking in Experiments 1 and 2, and a greatly reduced spatial release in Experiment 3. Faithful long-term average interaural level differences were insufficient for producing spatial release from masking. This suggests that appropriate interaural time differences are necessary for restoring spatial release from masking, at least for a situation where there are few viable alternative segregation cues.

Radar investigation of barium releases over Arecibo Observatory, Puerto Rico. Final report, 12 August 1991-30 June 1994

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

Djuth, F.T.

1995-07-01

The NASA Combined Release and Radiation Effects Satellite (CRRES) El Coqui rocket campaign was successfully carried out in Puerto Rico during the period 18 May through 12 July 1992. This report describes five chemical release experiments in the upper ionosphere supported by Geospace Research, Inc. during the El Coqui campaign. Additional spin-off science is also discussed. The El Coqui releases are designated AA-1 (rocket 36-082), AA-2 (rocket 36-081), AA-3b (rocket 36-064), AA-4 (rocket 36-065), and AA-7 (rocket 36-083). Particular attention is paid to releases AA-2 and AA-4. These two experiments involved the illumination of ionospheric release regions with powerful high-frequencymore » (HF) radio waves transmitted from the Arecibo HF facility. In the AA-2 experiment, microinstabilities excited by the HF wave in a Ba(+) plasma were examined. This release yielded a smooth plasma cloud that helped clarify several fundamental issues regarding the physics of wave plasma instabilities. During AA-2 extremely strong HF-induced Langmuir turbulence was detected with the Arecibo 430 MHz radar. CF3Br was released in the AA-4 study to create an ionospheric hole that focused the HF beam. This experiment successfully explored wave-plasma coupling in an O(+) ionosphere under conditions of very high HF electric field strengths.« less

Theory of single-molecule controlled rotation experiments, predictions, tests, and comparison with stalling experiments in F1-ATPase.

PubMed

Volkán-Kacsó, Sándor; Marcus, Rudolph A

2016-10-25

A recently proposed chemomechanical group transfer theory of rotary biomolecular motors is applied to treat single-molecule controlled rotation experiments. In these experiments, single-molecule fluorescence is used to measure the binding and release rate constants of nucleotides by monitoring the occupancy of binding sites. It is shown how missed events of nucleotide binding and release in these experiments can be corrected using theory, with F 1 -ATP synthase as an example. The missed events are significant when the reverse rate is very fast. Using the theory the actual rate constants in the controlled rotation experiments and the corrections are predicted from independent data, including other single-molecule rotation and ensemble biochemical experiments. The effective torsional elastic constant is found to depend on the binding/releasing nucleotide, and it is smaller for ADP than for ATP. There is a good agreement, with no adjustable parameters, between the theoretical and experimental results of controlled rotation experiments and stalling experiments, for the range of angles where the data overlap. This agreement is perhaps all the more surprising because it occurs even though the binding and release of fluorescent nucleotides is monitored at single-site occupancy concentrations, whereas the stalling and free rotation experiments have multiple-site occupancy.

Antigravity posture for analysis of motor unit recruitment: the "45 degree test".

PubMed

Petajan, J H

1990-04-01

The maximum number of different motor unit action potentials (MUAPs), their firing rates, and total MUAP spikes/second recorded by monopolar needle electrode were determined for the biceps brachii muscle during 45-degree elbow flexion. There were 4.2 +/- 1.6 different MUAPs exceeding 100 microV. Mean firing rate was 10.0 +/- 1.7 Hz, and total MUAP spikes/second were 40.3 +/- 18. Recordings from 16 patients with neurogenic atrophy (NA) and just detectable weakness revealed corresponding values of 3.1 +/- 1.7 different MUAPs, a mean rate of 10.2 +/- 1.5 Hz and 30.6 +/- 19 total MUAP spikes/second, not different from normal. In these patients, increased force of muscle contraction was required to activate high threshold motor units firing at high rates. In each of 4 patients just able to hold the arm against gravity, 1 or 2 "overdriven" motor units firing at a mean rate greater than 20 Hz were recorded. In 8 patients with myopathy and just detectable weakness, greater than 100 total MUAP spikes/second were recorded. Antigravity posture as a reference level of innervation has the advantage that motor unit firing rate is set about that of physiologic tremor (10-13 Hz). Its application was helpful in quantifying recruitment.

Intercellular crosstalk in human malignant melanoma.

PubMed

Dvořánková, Barbora; Szabo, Pavol; Kodet, Ondřej; Strnad, Hynek; Kolář, Michal; Lacina, Lukáš; Krejčí, Eliška; Naňka, Ondřej; Šedo, Aleksi; Smetana, Karel

2017-05-01

Incidence of malignant melanoma is increasing globally. While the initial stages of tumors can be easily treated by a simple surgery, the therapy of advanced stages is rather limited. Melanoma cells spread rapidly through the body of a patient to form multiple metastases. Consequently, the survival rate is poor. Therefore, emphasis in melanoma research is given on early diagnosis and development of novel and more potent therapeutic options. The malignant melanoma is arising from melanocytes, cells protecting mitotically active keratinocytes against damage caused by UV light irradiation. The melanocytes originate in the neural crest and consequently migrate to the epidermis. The relationship between the melanoma cells, the melanocytes, and neural crest stem cells manifests when the melanoma cells are implanted to an early embryo: they use similar migratory routes as the normal neural crest cells. Moreover, malignant potential of these melanoma cells is overdriven in this experimental model, probably due to microenvironmental reprogramming. This observation demonstrates the crucial role of the microenvironment in melanoma biology. Indeed, malignant tumors in general represent complex ecosystems, where multiple cell types influence the growth of genetically mutated cancer cells. This concept is directly applicable to the malignant melanoma. Our review article focuses on possible strategies to modify the intercellular crosstalk in melanoma that can be employed for therapeutic purposes.

Mobilization of natural colloids from an iron oxide-coated sand aquifer--Effect of pH and ionic strength

USGS Publications Warehouse

Bunn, Rebecca A.; Magelky, Robin D.; Ryan, Joseph N.; Elimelech, Menachem

2002-01-01

Field and laboratory column experiments were performed to assess the effect of elevated pH and reduced ionic strength on the mobilization of natural colloids in a ferric oxyhydroxide-coated aquifer sediment. The field experiments were conducted as natural gradient injections of groundwater amended by sodium hydroxide additions. The laboratory experiments were conducted in columns of undisturbed, oriented sediments and disturbed, disoriented sediments. In the field, the breakthrough of released colloids coincided with the pH pulse breakthrough and lagged the bromide tracer breakthrough. The breakthrough behavior suggested that the progress of the elevated pH front controlled the transport of the mobilized colloids. In the laboratory, about twice as much colloid release occurred in the disturbed sediments as in the undisturbed sediments. The field and laboratory experiments both showed that the total mass of colloid release increased with increasing pH until the concurrent increase in ionic strength limited release. A decrease in ionic strength did not mobilize significant amounts of colloids in the field. The amount of colloids released normalized to the mass of the sediments was similar for the field and the undisturbed laboratory experiments.

Atmospheric modeling of Mars CH4 subsurface clathrates releases mimicking SAM and 2003 Earth-based detections

NASA Astrophysics Data System (ADS)

Pla-García, J.; Rafkin, S. C.

2017-12-01

The aim of this work is to establish the amount of mixing during all martian seasons to test whether CH4 releases inside or outside of Gale crater are consistent with MSL-SAM observations. Several modeling scenarios were configured, including instantaneous and steady releases, both inside and outside the crater. A simulation to mimic the 2003 Earth-based detections (Mumma et al. 2009 or M09) was also performed. In the instantaneous release inside Gale experiments, Ls270 was shown to be the faster mixing season when air within and outside the crater was well mixed: all tracer mass inside the crater is diluted after just 8 hours. The mixing of near surface crater air with the external environment in the rest of the year is potentially rapid but slower than Ls270.In the instantaneous release outside Gale (NW) experiment, in just 12 hours the CH4 that makes it to the MSL landing location is diluted by six orders of magnitude. The timescale of mixing in MRAMS experiments is on the order of 1 sol regardless of season. The duration of the CH4 peak observed by SAM is 100 sols. Therefore there is a steady release inside the crater, or there is a very large magnitude steady release outside the crater. In the steady release Gale experiments, CH4 flux rate from ground is 1.8 kg m-2 s-1 (derived from Gloesener et al. 2017 clathrates fluxes) and it is not predictive. In these experiments, 200 times lower CH4 values detected by SAM are modeled around MSL location. There are CH4 concentration variations of orders of magnitude depending on the hour, so timing of SAM measurements is important. With a larger (but further away) outside crater release area compared to inside, similar CH4 values around MSL are modeled, so distance to source is important. In the steady experiments mimicking M09 detection release area, only 12 times lower CH4 values detected by SAM are modeled around MSL. The highest value in the M09 modeled scenario (0.6 ppbv) is reached in Ls270. This value is the highest of all modeled experiments. With our initial conditions (flux rates, release area size and distance to MSL), SAM should not be able (or very difficult) to detect CH4, but if we multiply flux by 12, increase the release area or move it closer to MSL (or all of above), it may be possible to get CH4 values that SAM could detect regardless where it comes from: inside, outside (close to) or far away from Gale.

A new tracer experiment to estimate the methane emissions from a dairy cow shed using sulfur hexafluoride (SF6)

NASA Astrophysics Data System (ADS)

Marik, Thomas; Levin, Ingeborg

1996-09-01

Methane emission from livestock and agricultural wastes contribute globally more than 30% to the anthropogenic atmospheric methane source. Estimates of this number have been derived from respiration chamber experiments. We determined methane emission rates from a tracer experiment in a modern cow shed hosting 43 dairy cows in their accustomed environment. During a 24-hour period the concentrations of CH4, CO2, and SF6, a trace gas which has been released at a constant rate into the stable air, have been measured. The ratio between SF6 release rate and measured SF6 concentration was then used to estimate the ventilation rate of the stable air during the course of the experiment. The respective ratio between CH4 or CO2 and SF6 concentration together with the known SF6 release rate allows us to calculate the CH4 (and CO2) emissions in the stable. From our experiment we derive a total daily mean CH4 emission of 441 LSTP per cow (9 cows nonlactating), which is about 15% higher than previous estimates for German cows with comparable milk production obtained during respiration chamber experiments. The higher emission in our stable experiment is attributed to the contribution of CH4 release from about 50 m3 of liquid manure present in the cow shed in underground channels. Also, considering measurements we made directly on a liquid manure tank, we obtained an estimate of the total CH4 production from manure: The normalized contribution of methane from manure amounts to 12-30% of the direct methane release of a dairy cow during rumination. The total CH4 release per dairy cow, including manure, is 521-530 LSTP CH4 per day.

Microgravity experiment system utilizing a balloon

NASA Astrophysics Data System (ADS)

Namiki, M.; Ohta, S.; Yamagami, T.; Koma, Y.; Akiyama, H.; Hirosawa, H.; Nishimura, J.

A system for microgravity experiments by using a stratospheric balloon has been planned and developed in ISAS since 1978. A rocket-shaped chamber mounting the experiment apparatus is released from the balloon around 30 km altitude. The microgravity duration is from the release to opening of parachute, controlled by an on-board sequential timer. Test flights were performed in 1980 and in 1981. In September 1983 the first scientific experiment, observing behaviors and brain activities of fishes in the microgravity circumstance, have been successfully carried out. The chamber is specially equipped with movie cameras and subtransmitters, and its release altitude is about 32 km. The microgravity observed inside the chamber is less than 2.9 × 10-3 G during 10 sec. Engineering aspects of the system used in the 1983 experiment are presented.

Atmospheric modeling of Mars CH4 subsurface clathrates releases mimicking SAM and 2003 Earth-based detections

NASA Astrophysics Data System (ADS)

Pla-Garcia, Jorge

2017-10-01

The aim of this work is to establish the amount of mixing during all martian seasons to test whether CH4 releases inside or outside of Gale crater are consistent with MSL-SAM observations. Several modeling scenarios were configured, including instantaneous and steady releases, both inside and outside the crater. A simulation to mimic the 2003 Earth-based detections (Mumma et al. 2009 or M09) was also performed. In the instantaneous release inside Gale experiments, Ls270 was shown to be the faster mixing season when air within and outside the crater was well mixed: all tracer mass inside the crater is diluted after just 8 hours. The mixing of near surface crater air with the external environment in the rest of the year is potentially rapid but slower than Ls270. In the instantaneous release outside Gale (NW) experiment, in just 12 hours the CH4 that makes it to the MSL landing location is diluted by six orders of magnitude. The timescale of mixing in the model is on the order of 1 sol regardless of season. The duration of the CH4 peak observed by SAM is 100 sols. Therefore there is a steady release inside the crater, or there is a large magnitude steady release outside the crater. In the steady release Gale experiments, CH4 flux rate from ground is 1.8 kg m-2 s-1 (Gloesener et al. 2017) and it is not predictive. In these experiments, ~200 times lower CH4 values detected by SAM are modeled around MSL location. There are CH4 concentration variations of orders of magnitude depending on the hour, so timing of SAM measurements is important. With a larger (but further away) outside crater release area compared to inside, similar CH4 values around MSL are modeled, so distance to source is important. In the steady experiments mimicking M09 detection release area, only 12 times lower CH4 values detected by SAM are modeled around MSL. The highest value in the M09 modeled scenario (0.6 ppbv) is reached in Ls270. This value is the highest of all modeled experiments. With our initial conditions, SAM should not be able to detect CH4, but if we multiply flux by 12, increase the release area or move it closer to MSL (or all of above), it may be possible to get CH4 values that SAM could detect regardless where it comes from.

Chemical release and radiation effects experiment advanced planning and coordination

NASA Technical Reports Server (NTRS)

Vaughan, William W.; Alzmann, Melanie

1991-01-01

The efforts conducted to provide assessments and planning support for the Chemical Release and Radiation Effects Satellite (CRRES) Experiments are summarized. Included are activities regarding scientific working group and workshop development including the preparation of descriptive information on the CRRES Project.

Chemical release and radiation effects experiment advanced planned

NASA Technical Reports Server (NTRS)

Vaughan, William W.; Alzmann, Melanie

1990-01-01

A summary of the efforts conducted to provide assessments and planning support for the Chemical Release and Radiation Experiment Satellite (CRRES) is reported. Included are activities regarding scientific working group and workshop development including the preparation of descriptive information on the CRRES project.

Using the Viking biology experimental results to obtain chemical information about Martian regolith

NASA Technical Reports Server (NTRS)

Plumb, Robert C.

1992-01-01

Although initially formulated as biology experiments, most of the results produced by the Viking Labeled Release (LR), Gas Exchange (GEX), and Pyrolytic Release (PR) experiments have been reproduced by chemical means. The experiments do not need more study as 'biological' phenomena, but they do deserve much more careful consideration from a chemical viewpoint. They are the only 'wet-chemical' experiments that scientists have performed on another planet, but they have not found very general use as sources of scientific information. There is a large set of potentially useful chemical observations, e.g., the three resolvable and precisely measured kinetic components of the release of C-14-labeled gases, the thermal sensitivity and magnitudes of the oxidation reaction(s) of the LR experiments, the kinetics and magnitude of the O2 and CO2 release of the GEX experiments, the thermal sensitivity of the GEX results, the differences between the thermal sensitivity of the GEX and the thermal sensitivity of the LR responses, and the kinetics and magnitudes of the LR successive injection reabsorption effect. It should be possible to test many chemical aspects of hypothetical martian phenomena in experiments using the biology experimental configurations and derive much valuable information by comparisons with the Viking observations.

Coatings from blends of Eudragit® RL and L55: a novel approach in pH-controlled drug release.

PubMed

Wulff, R; Leopold, C S

2014-12-10

The aim of the present study was to investigate the drug release from theophylline pellets coated with blends of quaternary polymethacrylate and methacrylic acid-ethyl acrylate copolymers. Pellets were coated with blends of Eudragit(®) RL PO (RL) and Eudragit(®) L 100-55 (L55) in either organic solution or aqueous dispersion at various copolymer ratios. Generally, the coatings were less permeable for theophylline in phosphate buffer pH 6.8 than they were in hydrochloric acid pH 1.2. Further dissolution experiments revealed that the differences in drug release are caused by the different pH values. A design of experiments for historical data was performed on drug release data of pellets with different coating levels and blend ratios of RL and L55. Drug release in hydrochloric acid was predominantly affected by the coating level, whereas for drug release in phosphate buffer pH 6.8 the blend ratio was the determining factor. As expected, dissolution experiments at different pH values showed that drug release depends on the ratio of dissociated L55 to RL because ionization is a requirement for the functional groups to interact. With the dissolution test for delayed-release solid dosage forms (Ph. Eur.) it was demonstrated that the unique release behavior in neutral media is preserved after the exposition to hydrochloric acid. These findings indicate that the combination of RL and L55 in coatings prepared from solutions is a promising approach for controlled drug release. Copyright © 2014 Elsevier B.V. All rights reserved.

Gender differences in treatment and clinical characteristics among patients receiving extended release naltrexone.

PubMed

Herbeck, Diane M; Jeter, Kira E; Cousins, Sarah J; Abdelmaksoud, Reham; Crèvecoeur-MacPhail, Desirée

2016-01-01

Further research is needed to investigate real-world acceptability of extended-release naltrexone for alcohol and opioid use disorders, and potential gender differences. This study examines treatment and clinical characteristics among men and women receiving extended-release naltrexone in a large, publicly funded substance use disorder treatment system (N = 465; 52% female). Patient demographics, treatment characteristics, and the number of extended-release naltrexone doses received were collected from administrative data and treatment program staff. Additionally, patients provided information on experiences with extended-release naltrexone in an open-ended format at 1, 2, and 3 weeks following their first injection. For a subsample of patients (N = 220), alcohol/opioid cravings and specific adverse effects were also assessed. Compared to men, women reported experiencing a higher rate and mean number of adverse effects. Overall, craving scores showed substantial reductions over time. However, among patients taking extended-release naltrexone for alcohol use, women showed a significantly greater reduction in craving scores compared to men. No gender differences were observed in the number of extended-release naltrexone doses received. Although women may have a greater need for additional support in managing early adverse effects, extended-release naltrexone as an adjunct to psychosocial treatment may be an acceptable and promising treatment approach for both men and women, and particularly for women prescribed extended-release naltrexone for alcohol use. This study contributes further information on patients' experiences during the early course of extended-release naltrexone treatment in real-world settings. Understanding these experiences may assist policy makers and treatment providers in addressing challenges of implementing this treatment into wider practice.

Peroxide-modified titanium dioxide: a chemical analog of putative Martian soil oxidants

NASA Technical Reports Server (NTRS)

Quinn, R. C.; Zent, A. P.

1999-01-01

Hydrogen peroxide chemisorbed on titanium dioxide (peroxide-modified titanium dioxide) is investigated as a chemical analog to the putative soil oxidants responsible for the chemical reactivity seen in the Viking biology experiments. When peroxide-modified titanium dioxide (anatase) was exposed to a solution similar to the Viking labeled release (LR) experiment organic medium, CO2 gas was released into the sample cell headspace. Storage of these samples at 10 degrees C for 48 hr prior to exposure to organics resulted in a positive response while storage for 7 days did not. In the Viking LR experiment, storage of the Martian surface samples for 2 sols (approximately 49 hr) resulted in a positive response while storage for 141 sols essentially eliminated the initial rapid release of CO2. Heating the peroxide-modified titanium dioxide to 50 degrees C prior to exposure to organics resulted in a negative response. This is similar to, but not identical to, the Viking samples where heating to approximately 46 degrees C diminished the response by 54-80% and heating to 51.5 apparently eliminated the response. When exposed to water vapor, the peroxide-modified titanium dioxide samples release O2 in a manner similar to the release seen in the Viking gas exchange experiment (GEx). Reactivity is retained upon heating at 50 degrees C for three hours, distinguishing this active agent from the one responsible for the release of CO2 from aqueous organics. The release of CO2 by the peroxide-modified titanium dioxide is attributed to the decomposition of organics by outer-sphere peroxide complexes associated with surface hydroxyl groups, while the release of O2 upon humidification is attributed to more stable inner-sphere peroxide complexes associated with Ti4+ cations. Heating the peroxide-modified titanium dioxide to 145 degrees C inhibited the release of O2, while in the Viking experiments heating to this temperature diminished but did not eliminated the response. Although the thermal stability of the titanium-peroxide complexes in this work is lower than the stability seen in the Viking experiments, it is expected that similar types of complexes will form in titanium containing minerals other than anatase and the stability of these complexes will vary with surface hydroxylation and mineralogy.

Perchlorate Salts in the Martian Surface Environment - A Reexamination of the 1976 Viking Biology Results

NASA Astrophysics Data System (ADS)

Dillon, James; Quinn, R. C.

2010-01-01

The Viking Mars landers of 1976 conducted three biology experiments designed to detect the presence of microbial life in the Martian surface. The gas exchange experiment carried out by the Viking landers periodically sampled the gaseous headspace of Mars soil samples saturated with an organic/inorganic aqueous mixture, M4 nutrient. A gas chromatograph measured the change in concentrations of N2, O2, CO2, Kr, H2, and CH4 over various time intervals. The presence of metabolically active microbial life would be confirmed by the consumption or release of one of these gases. A significant release of O2 was detected after the addition of nutrient, however since the Gas Chromatograph - Mass Spectrometer experiment did not detect organics in the soil, this rapid release of O2 could not be attributed to microbial life, but rather a chemical reaction. The recent discovery of the oxidizer perchlorate in the Martian soil by the Phoenix Mars lander was investigated as the principal cause of this O2 release detected by the Viking gas exchange experiment. A variety of oxychloride salts ranging from hypochlorite to perchlorate were examined under conditions similar to the Viking experiment in order to determine if a rapid release of O2 would be detected upon addition of M4 nutrient. No oxychloride species examined decomposed with the kinetics required to support an oxychloride as the cause of the O2 response detected by the Viking experiment.

[Decomposition dynamics of leaf litter in logging residue of a secondary Castanopsis carlesii plantation and its chemical composition changes].

PubMed

Ren, Wei-ling; Guo, Jian-fen; Wu, Bo-bo; Wan, Jing-juan; Ji, Shu-rong; Liu, Xiao-fei

2015-04-01

A field experiment was conducted to understand the decomposition rates and chemical composition changes of leaf litter in logging residues of a 35-year-old secondary Castanopsis carlesii plantation over a period of one year. Mass loss rate of leaf litter showed an exponential decrease with time from May 2012 to April 2013, with a total 80% loss of initial dry mass. Net potassium (K) release was observed during this period, with only 5% of initial K remained. Nitrogen ( N) featured a pattern of accumulation at the early stage and release later, while phosphorus (P) exhibited a sequence of release, accumulation, and release. The remaining of N and P were 19% and 16% of their initial mass, respectively. The release rate was highest for K and the lowest for N. Decomposition of lignin indicated a trend of release-accumulation-release from May 2012 to October 2012, with no further significant change from November 2012 to the end of the experiment. The concentration of cellulose nearly unchanged during the experiment. The N/P rate increased with decomposition, ranging from 18.6 to 21.1. The lignin/N rate fluctuated greatly at the early stage and then almost stabilized thereafter.

Smectites versus palagonites in Mars soil: Evidence from simulations of Viking biology labeled release experiments

NASA Technical Reports Server (NTRS)

Banin, A.; Margulies, L.

1983-01-01

The results of an experimental comparison between palagonites and a smectite (montmorillonite) in the simulation of the Viking Biology Labeled Release (LR) experiment and conclusions regarding their suitability as MarSAMs are reproved. It was found that palagonites do not cause formate decomposition and C-14 release in their natural form or after acidification and thus cannot be a completely satisfactory analog to the Mars soil studied by Viking.

Combined Release and Radiation Effects Satellite (CRRES) Experiment: Educational planning and coordination

NASA Technical Reports Server (NTRS)

Vaughan, William W.; Alzmann, Melanie

1991-01-01

The efforts conducted to provide educational planning and development support for the Combined Release and Radiation Satellite (CRRES) Experiment are summarized. Activities regarding the scientific working group and workshop development are presented including the preparation of descriptive information on the CRRES Project.

Oxidation of formic acid by oxyanions of chlorine and its implications to the Viking Labeled Release experiment

NASA Astrophysics Data System (ADS)

Martinez, P.; Navarro-gonzalez, R.

2013-05-01

The Viking Landers that arrived on Mars in 1976 carried out three biological experiments designed to investigate if there was microbial life. These were the Gas-Exchange, Pyrolitic Release and Labeled Release experiments. The three experiments yielded positive responses but the Labeled Release experiment had a kinetic response indicative of microbial activity. The experiment consisted of adding a broth of nutrients (formic acid, glycolic acid, glycine, D- and L-alanine and D- and L-lactic acid uniformly marked with 14C) to martian soil samples. The results were surprising; the nutrients were consumed releasing radioactive gases in a manner that is compatible by terrestrial microorganisms. The existence of Martian life was contradicted by soil chemical analysis that indicated the absence of organic compounds above the detection limits of parts per billion (ppb). Instead the positive response of the Labeled Release Experiment was attributed to the existence of peroxides and/or superoxides in the Martian soils that destroyed the nutrients upon contact. Recently, the Phoenix mission that landed in the Martian Arctic in 2008 revealed the presence of a highly oxidized form of the element chlorine in the soil: perchlorate. Perchlorate is thought to have formed in the Martian atmosphere by the oxidation of chloride from volcanic sources with ozone. Therefore perchlorate is formed by the stepwise oxidation of hypochlorite, chlorite and chlorate. These oxyanions of chlorine are powerful oxidizers that may exist in the Martian soil and may have reacted with the nutrients of the Labeled Release Experiment. This paper aims to better understand these results by designing experiments to determine the kinetics of decomposition of formic acid to carbon dioxide with different oxidized forms of chlorine by headspace technique in gas chromatography coupled to mass spectrometry (GC / MS). Previous studies done in the laboratory showed that only hypochlorite quantitatively reacted with the formate, this is why we conducted experiments at 20 ° C, 30 ° C and 40 ° C at times 0, 0.1, 0.5, 1, 3 , 5, 10, 20, 30, 40 and 60 min. The resulting kinetics were similar to those obtained by the LR experiment, however the speeds at which reacted in the laboratory were very rapid, almost instantaneous, a comparison of the acquired by the Viking was kinetics days. This may be because in the laboratory we do not used soil samples, Viking used Mars regolith Martian, like a complex matrix that may affect the reaction rate. We conclude that the response obtained by the LR experiment is possibly due to the presence of oxyanions of chlorine, hypochlorite specific which is increased by the dismutations chlorine species in solution, all in combination with other components very likely soil nutrients reacted with isotopically labeled. This project is still ongoing, open a new hypothesis of whether there is microbial life on Mars, since, if the Labeled Release experiment found no biological activity, may have been a chemical oxidation of organic nutrients for sodium hypochlorite .

A computer program to determine the possible daily release window for sky target experiments

NASA Technical Reports Server (NTRS)

Michaud, N. H.

1973-01-01

A computer program is presented which is designed to determine the daily release window for sky target experiments. Factors considered in the program include: (1) target illumination by the sun at release time and during the tracking period; (2) look angle elevation above local horizon from each tracking station to the target; (3) solar depression angle from the local horizon of each tracking station during the experimental period after target release; (4) lunar depression angle from the local horizon of each tracking station during the experimental period after target release; and (5) total sky background brightness as seen from each tracking station while viewing the target. Program output is produced in both graphic and data form. Output data can be plotted for a single calendar month or year. The numerical values used to generate the plots are furnished to permit a more detailed review of the computed daily release windows.

Mechanistic modelling of drug release from polymer-coated and swelling and dissolving polymer matrix systems.

PubMed

Kaunisto, Erik; Marucci, Mariagrazia; Borgquist, Per; Axelsson, Anders

2011-10-10

The time required for the design of a new delivery device can be sensibly reduced if the release mechanism is understood and an appropriate mathematical model is used to characterize the system. Once all the model parameters are obtained, in silico experiments can be performed, to provide estimates of the release from devices with different geometries and compositions. In this review coated and matrix systems are considered. For coated formulations, models describing the diffusional drug release, the osmotic pumping drug release, and the lag phase of pellets undergoing cracking in the coating due to the build-up of a hydrostatic pressure are reviewed. For matrix systems, models describing pure polymer dissolution, diffusion in the polymer and drug release from swelling and eroding polymer matrix formulations are reviewed. Importantly, the experiments used to characterize the processes occurring during the release and to validate the models are presented and discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

Correctional Education Experiences of Female Offenders with a Learning Disability

ERIC Educational Resources Information Center

Smith, Ezekiel

2012-01-01

Minimal employable skills, poor work habits, and substance abuse are problems that often result in released female offenders' recidivating within 36 months of their prison release. Recidivism is further compounded when the female offender suffers from a learning disability. Research suggests that correctional education experiences do not address…

Behavioral aspects of Lutzomyia longipalpis (Diptera: Psychodidae) in urban area endemic for visceral leishmaniasis.

PubMed

De Oliveira, E F; Silva, E A; Casaril, A E; Fernandes, C E S; Paranhos Filho, A C; Gamarra, R M; Ribeiro, A A; Brazil, R P; Oliveira, A G

2013-03-01

The study of some of the behavioral aspects of the main vector of Leishmania infantum chagasi Cunha & Chagas in the Americas, Lutzomyia longipalpis (Lutz & Neiva), such as dispersion, population size, and vector survival rates, is important for the elucidation of the mechanisms of visceral leishmaniasis transmission. These parameters were studied by means of capture-mark-release-recapture experiments in an urban area of Campo Grande municipality, an endemic area of visceral leishmaniasis, situated in Mato Grosso do Sul state, Brazil. Six capture-mark-release-recapture experiments were undertaken between November 2009 and November 2010 and once in January 2012 with a view to assessing the population size and survival rate of Lu. longipalpis. The insects were released in a peridomicile surrounded by 13 residences. The recaptures were undertaken with automatic light traps for four consecutive weeks after release in the surrounding area. In total, 3,354 sand flies were captured, marked, and released. The overall recapture rate during the capture-mark-release-recapture experiments was 4.23%, of which 92.45% were recaptured at the release site, indicating limited dispersal. The greatest distance recorded from the release site was 165 m for males and 241 m for females. The male daily survival rate, calculated on the basis of regressions from the numbers of marked recaptured insects during the 15 successive days after release was 0.897. The estimated male population size measured by the Lincoln Index was 10,947.127. Though Lu. longipalpis presented a limited dispersion the physical barriers typical of urban environments did not prevent the sand flies from flying long distances.

Dissolution kinetics of a lunar glass simulant at 25 degrees C: the effect of pH and organic acids

NASA Technical Reports Server (NTRS)

Eick, M. J.; Grossl, P. R.; Golden, D. C.; Sparks, D. L.; Ming, D. W.

1996-01-01

The dissolution kinetics of a simulated lunar glass were examined at pH 3, 5, and 7. Additionally, the pH 7 experiments were conducted in the presence of citric and oxalic acid at concentrations of 2 and 20 mM. The organic acids were buffered at pH 7 to examine the effect of each molecule in their dissociated form. At pH 3, 5, and 7, the dissolution of the synthetic lunar glass was observed to proceed via a two-stage process. The first stage involved the parabolic release of Ca, Mg, Al, and Fe, and the linear release of Si. Dissolution was incongruent, creating a leached layer rich in Si and Ti which was verified by transmission electron microscopy (TEM). During the second stage the release of Ca, Mg, Al, and Fe was linear. A coupled diffusion/surface dissolution model was proposed for dissolution of the simulated lunar glass at pH 3, 5, and 7. During the first stage the initial release of mobile cations (i.e., Ca, Mg, Al, Fe) was limited by diffusion through the surface leached layer of the glass (parabolic release), while Si release was controlled by the hydrolysis of the Si-O-Al bonds at the glass surface (linear release). As dissolution continued, the mobile cations diffused from greater depths within the glass surface. A steady-state was then reached where the diffusion rate across the increased path lengths equalled the Si release rate from the surface. In the presence of the organic acids, the dissolution of the synthetic lunar glass proceeded by a one stage process. The release of Ca, Mg, Al, and Fe followed a parabolic relationship, while the release of Si was linear. The relative reactivity of the organic acids used in the experiments was citrate > oxalate. A thinner leached layer rich in Si/Ti, as compared to the pH experiments, was observed using TEM. Rate data suggest that the chemisorption of the organic anion to the surface silanol groups was responsible for enhanced dissolution in the presence of the organic acids. It is proposed that the increased rate of Si release is responsible for the one stage parabolic release of mobile cations and the relatively thin leached layer compared to experiments at pH 3 and 5.

Formation and Release of Cobalt(II) Sorption and Precipitation Products in Aging Kaolinite-Water Slurries.

PubMed

Thompson; Parks; Brown

2000-02-15

The uptake and release behavior of cobalt(II) was studied over thousands of hours in CO(2)-free aqueous suspensions of kaolinite under three pairs of total cobalt concentration (Co(T)) and near-neutral pH (7.5-7.8) conditions. Dissolved cobalt, aluminum, and silicon concentrations were monitored by ICPMS, and cobalt-containing products were identified by EXAFS spectroscopy. In each uptake experiment, cobalt sorbed to kaolinite as a mixture of surface-adsorbed monomers or polymers and hydrotalcite-like precipitates of the approximate composition Co(x)Al(OH)(2x+2)(A(n-))(1/n), where 2

Dynamical Effects in Metal-Organic Frameworks: The Microporous Materials as Shock Absorbers

NASA Astrophysics Data System (ADS)

Banlusan, Kiettipong; Strachan, Alejandro

2017-06-01

Metal-organic frameworks (MOFs) are a class of nano-porous crystalline solids consisting of inorganic units coordinated to organic linkers. The unique molecular structures and outstanding properties with ultra-high porosity and tunable chemical functionality by various choices of metal clusters and organic ligands make this class of materials attractive for many applications. The complex and quite unique responses of these materials to mechanical loading including void collapse make them attractive for applications in energy absorption and storage. We will present using large-scale molecular dynamics simulations to investigate shock propagation in zeolitic imidazolate framework ZIF-8 and MOF-5. We find that for shock strengths above a threshold a two-wave structure develops with a leading elastic precursor followed by a second wave of structural collapse to relax the stress. Structural transition of MOFs in response to shock waves corresponds to the transition between two Hugoniot curves, and results in abrupt change in temperature. The pore-collapse wave propagates at slower velocity than the leading wave and weakens it, resulting in shock attenuation. Increasing piston speed results in faster propagation of pore-collapse wave, but the leading elastic wave remains unchanged below the overdriven regime. We discuss how the molecular structure of the MOFs and shock propagation direction affect the response of the materials and their ability to weaken shocks. Office of Naval Research, MURI 2012 02341 01.

rhoCentralRfFoam: An OpenFOAM solver for high speed chemically active flows - Simulation of planar detonations -

NASA Astrophysics Data System (ADS)

Gutiérrez Marcantoni, L. F.; Tamagno, J.; Elaskar, S.

2017-10-01

A new solver developed within the framework of OpenFOAM 2.3.0, called rhoCentralRfFoam which can be interpreted like an evolution of rhoCentralFoam, is presented. Its use, performing numerical simulations on initiation and propagation of planar detonation waves in combustible mixtures H2-Air and H2-O2-Ar, is described. Unsteady one dimensional (1D) Euler equations coupled with sources to take into account chemical activity, are numerically solved using the Kurganov, Noelle and Petrova second order scheme in a domain discretized with finite volumes. The computational code can work with any number of species and its corresponding reactions, but here it was tested with 13 chemically active species (one species inert), and 33 elementary reactions. A gaseous igniter which acts like a shock-tube driver, and powerful enough to generate a strong shock capable of triggering exothermic chemical reactions in fuel mixtures, is used to start planar detonations. The following main aspects of planar detonations are here, treated: induction time of combustible mixtures cited above and required mesh resolutions; convergence of overdriven detonations to Chapman-Jouguet states; detonation structure (ZND model); and the use of reflected shocks to determine induction times experimentally. The rhoCentralRfFoam code was verified comparing numerical results and it was validated, through analytical results and experimental data.

Theoretical transient analysis of a hearing aid feedback canceller with a saturation type nonlinearity in the direct path.

PubMed

Costa, Márcio Holsbach

2017-12-01

Feedback cancellation in a hearing aid is essential for achieving high maximum stable gain to compensate for the losses in severe to profound hearing impaired people. The performance of adaptive feedback cancellers has been studied by assuming that the feedback path can be modeled as a linear system. However, limited dynamic range, low-cost loudspeakers, and nonlinear power amplifiers may distort the hearing aid output signal. In this way, linear-based predictions of the canceller performance may lead to significant deviations from its actual behavior. This work presents a theoretical performance analysis of a Least Mean Square based shadow filter that is applied to set up the coefficients of a feedback canceller, which is subject to a static saturation type nonlinearity at the output of the direct path. Deterministic recursive equations are derived to predict the mean square feedback error and the mean coefficient vector evolution between updates of the feedback canceller. These models are defined as functions of the canceller parameters and input signal statistics. Comparisons with Monte Carlo simulations show the provided models are highly accurate under the considered assumptions. The developed models allow inferences about the potential impact of an overdriven loudspeaker over the transient performance of the direct method feedback canceller, serving as insightful tools for understanding the involved mechanisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Varying Iron Release from Transferrin and Lactoferrin Proteins. A Laboratory Experiment

ERIC Educational Resources Information Center

Carmona, Fernando; González, Ana; Sánchez, Manu; Gálvez, Natividad; Cuesta, Rafael; Capdevila, Mercè; Dominguez-Vera, Jose M.

2017-01-01

Iron metabolism is an important subject of study for undergraduate students of chemistry and biochemistry. Relevant laboratory exercises are scarce in the literature but would be very helpful in assisting students grasp key concepts. The experiment described here deals with different iron release mechanisms of two protagonists in iron metabolism:…

Notice of release for Eagle Germplasm western yarrow (selected germplasm, natural track)

Treesearch

Scott M. Lambert; Stephen B. Monsen; Nancy Shaw

2011-01-01

The United States Department of Agriculture, Forest Service, Rocky Mountain Research Station; United States Department of the Interior, Bureau of Land Management, Idaho State Office; Utah State University, Agricultural Experiment Station; and University of Idaho, Agricultural Experiment Station, announce the release of a selected germplasm (natural track) of western...

From Corrections to Community: The Juvenile Reentry Experience as Characterized by Multiple Systems Involvement

ERIC Educational Resources Information Center

Cusick, Gretchen Ruth; Goerge, Robert M.; Bell, Katie Claussen

2009-01-01

This Chapin Hall report describes findings on the extent of system involvement among Illinois youth released from correctional facilities, tracking a population of youth under age 18 in Illinois following their release. Using administrative records, researchers develop profiles of reentry experiences across the many systems that serve youth and…

Kinetic Release of Alkalinity from Particle-Containing Oil-in-Water Emulsions

NASA Astrophysics Data System (ADS)

Muller, K.; Chapra, S. C.; Ramsburg, A.

2014-12-01

Oil-in-water emulsions are typically employed during remediation to promote biotic reduction of contaminants. Emulsions, however, hold promise for encapsulated delivery of many types of active ingredients required for successful site remediation or long-term site stewardship. Our research is currently focused on using alkalinity-containing particles held within oil-in-water emulsions to sustain control of subsurface pH. Here we describe results from laboratory experiments and mathematical modeling conducted to quantify the kinetics associated with the emulsion delivery and alkalinity release process. Kinetically stable oil-in-water emulsions containing (~60 nmCaCO3 or ~100 nm MgO particles) were previously developed using soybean oil and Gum Arabic as a stabilizing agent. Batch and column experiments were employed to assess the accessibility and release of the alkalinity from the emulsion. Successive additions of HCl were used in batch systems to produce several pH responses (pH rebounds) that were subsequently modeled to elucidate release mechanisms and rates for varying emulsion compositions and particle types. Initial results suggest that a linear-driving-force model is generally able to capture the release behavior in the batch system when the temporally-constant, lumped mass-transfer coefficient is scaled by the fraction of particle mass remaining within the droplets. This result suggests that the rate limiting step in the release process may be the interphase transfer of reactive species at the oil-water interface. 1-d column experiments were also completed in order to quantify the extent and rate of alkalinity release from emulsion droplets retained in a sandy medium. Alkalinity release from the retained droplets treated a pH 4 influent water for 25-60 pore volumes (the duration depended on particle type and mass loading), and the cessation in treatment corresponded to exhaustion of the particle mass held within the oil. Column experiments were simulated using a transport code containing the linear-driving-force expression evaluated in the batch experiments. In these simulations the lumped mass transfer coefficient was fit and compared with values predicted using existing correlations for liquid-liquid and solid-liquid interfaces in porous media.

Effect of mean diameter and polydispersity of PLG microspheres on drug release: experiment and theory.

PubMed

Berchane, N S; Carson, K H; Rice-Ficht, A C; Andrews, M J

2007-06-07

The need to tailor release rate profiles from polymeric microspheres is a significant problem. Microsphere size, which has a significant effect on drug release rate, can potentially be varied to design a controlled drug delivery system with desired release profile. In this work the effects of microspheres mean diameter, polydispersity, and polymer degradation on drug release rate from poly(lactide-co-glycolide) (PLG) microspheres are described. Piroxicam containing PLG microspheres were fabricated at 20% loading, and at three different impeller speeds. A portion of the microspheres was then sieved giving five different size distributions. In vitro release kinetics were determined for each preparation. Based on these experimental results, a suitable mathematical theory has been developed that incorporates the effect of microsphere size distribution and polymer degradation on drug release. We show from in vitro release experiments that microsphere size has a significant effect on drug release rate. The initial release rate decreased with an increase in microsphere size. In addition, the release profile changed from first order to concave-upward (sigmoidal) as the microsphere size was increased. The mathematical model gave a good fit to the experimental release data. For highly polydisperse populations (polydispersity parameter b<3), incorporating the microsphere size distribution into the mathematical model gave a better fit to the experimental results than using the representative mean diameter. The validated mathematical model can be used to predict small-molecule drug release from PLG microsphere populations.

Presynaptic control of dopamine release by BETA-phenylethylamine

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

Zharikova, A.D.; Godukhin, O.V.

The authors study the effect of extracellular ions (Ca/sup 2 +/, Na/sup 2 +/) on the beta-phenylethylamine (beta-PEA) releasing effect, dependence of this effect on the membrane potential of dopaminergic endings, and the participation of dopamine presynaptic autoreceptors in the realization of the effects of beta-PEA on dopamine (DA) release. Experi ments were carried out on noninbred male albino rats. By means of a microsyringe, (/sup 3/H)-DA hydrochloride was injected. The significance of the difference in levels of (/sup 3/H)-DA release during analogous periods of perfusion in the groups of animals compared was estimated by Student's test. These experiments inmore » vivo thus demonstrated the ability of beta-PEA to regulate DA release in different directions depending on the functional state of the dopaminergic neuron.« less

Comparison of silver release predictions using PARFUME with results from the AGR-2 irradiation experiment

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

Collin, Blaise P.; Demkowicz, Paul A.; Baldwin, Charles A.

2016-11-01

The PARFUME (PARticle FUel ModEl) code was used to predict silver release from tristructural isotropic (TRISO) coated fuel particles and compacts during the second irradiation experiment (AGR-2) of the Advanced Gas Reactor Fuel Development and Qualification program. The PARFUME model for the AGR-2 experiment used the fuel compact volume average temperature for each of the 559 days of irradiation to calculate the release of fission product silver from a representative particle for a select number of AGR-2 compacts and individual fuel particles containing either mixed uranium carbide/oxide (UCO) or 100% uranium dioxide (UO2) kernels. Post-irradiation examination (PIE) measurements were performedmore » to provide data on release of silver from these compacts and individual fuel particles. The available experimental fractional releases of silver were compared to their corresponding PARFUME predictions. Preliminary comparisons show that PARFUME under-predicts the PIE results in UCO compacts and is in reasonable agreement with experimental data for UO2 compacts. The accuracy of PARFUME predictions is impacted by the code limitations in the modeling of the temporal and spatial distributions of the temperature across the compacts. Nevertheless, the comparisons on silver release lie within the same order of magnitude.« less

Alcohol, Aldehyde, and Ketone Liberation and Intracellular Cargo Release through Peroxide-Mediated α-Boryl Ether Fragmentation.

PubMed

Hanna, Ramsey D; Naro, Yuta; Deiters, Alexander; Floreancig, Paul E

2016-10-12

α-Boryl ethers, carbonates, and acetals, readily prepared from the corresponding alcohols that are accessed through ketone diboration, react rapidly with hydrogen peroxide to release alcohols, aldehydes, and ketones through the collapse of hemiacetal intermediates. Experiments with α-boryl acetals containing a latent fluorophore clearly demonstrate that cargo can be released inside cells in the presence of exogenous or endogenous hydrogen peroxide. These experiments show that this protocol can be used for drug activation in an oxidative environment without generating toxic byproducts.

Effects of Extended-Release Niacin and Extended-Release Niacin/Laropiprant on the Pharmacokinetics of Simvastatin in Healthy Subjects.

PubMed

Lauring, Brett; Dishy, Victor; De Kam, Pieter-Jan; Crumley, Tami; Wenning, Larissa; Liu, Fang; Sisk, Christine; Wagner, John; Lai, Eseng

2015-01-01

The use of multiple lipid-modifying agents with different mechanisms of action is often required to regulate lipid levels in patients with dyslipidemia. During combination therapy, alterations in the pharmacokinetics of any of the drugs used and their metabolites may occur. Three separate open-label, randomized, crossover studies evaluated the potential for pharmacokinetic interaction between extended-release niacin (with and without concomitant laropiprant) and simvastatin in healthy subjects. Study 1 used single doses of extended-release niacin and simvastatin; study 2 used multiple-dose coadministration of extended-release niacin/laropiprant and simvastatin in healthy subjects; and study 3 used single doses of both extended-release niacin and the coadministration of extended-release niacin/laropiprant and simvastatin in healthy Chinese subjects. During each treatment period, plasma samples were collected predose and at prespecified postdose time points for pharmacokinetic analyses. The safety and tolerability of simvastatin with and without coadministered extended-release niacin (or extended-release niacin/laropiprant) were assessed by clinical evaluation of adverse experiences. In 2 studies in healthy subjects, modest increases in exposure to simvastatin acid (by ∼60%) by extended-release niacin and extended-release niacin/laropiprant were observed. Based on the clinical experience with simvastatin, these effects are not believed to be clinically meaningful. In the third study on healthy Chinese subjects, no statistically meaningful increases in exposure to simvastatin by extended-release niacin and extended-release niacin/laropiprant were observed. In all populations examined in these studies, the coadministration of extended-release niacin and simvastatin was generally well tolerated.

The field campaigns of the European Tracer Experiment (ETEX). overview and results

NASA Astrophysics Data System (ADS)

Nodop, K.; Connolly, R.; Girardi, F.

As part of the European Tracer Experiment (ETEX) two successful atmospheric experiments were carried out in October and November, 1994. Perfluorocarbon (PFC) tracers were released into the atmosphere in Monterfil, Brittany, and air samples were taken at 168 stations in 17 European countries for 72 h after the release. Upper air tracer measurements were made from three aircraft. During the first experiment a westerly air flow transported the tracer plume north-eastwards across Europe. During the second release the flow was eastwards. The results from the ground sampling network allowed the determination of the cloud evolution as far as Sweden, Poland and Bulgaria. This demonstrated that the PFT technique can be successfully applied in long-range tracer experiments up to 2000 km. Typical background concentrations of the tracer used are around 5-7 fl ℓ -1 in ambient air. Concentrations in the plume ranged from 10 to above 200 fl/ℓ -1. The tracer release characteristics, the tracer concentrations at the ground and in upper air, the routine and additional meteorological observations at the ground level and in upper air, trajectories derived from constant-level balloons and the meteorological input fields for long-range transport models are assembled in the ETEX database. The ETEX database is accessible via the Internet. Here, an overview is given of the design of the experiment, the methods used and the data obtained.

Preparation and characterization of poly(ε-caprolactone) nanospheres containing the local anesthetic lidocaine.

PubMed

Ramos Campos, Estefânia Vangelie; Silva de Melo, Nathalie Ferreira; Guilherme, Viviane Aparecida; de Paula, Eneida; Rosa, André Henrique; de Araújo, Daniele Ribeiro; Fraceto, Leonardo Fernandes

2013-01-01

The objective of this work was to develop a modified release system for the local anesthetic lidocaine (LDC), using poly(ε-caprolactone) (PCL) nanospheres (NSs), to improve the pharmacological properties of the drug when administered by the infiltration route. In vitro experiments were used to characterize the system and investigate the release mechanism. The NSs presented a polydispersion index of 0.072, an average diameter of 449.6 nm, a zeta potential of -20.1 mV, and an association efficiency of 93.3%. The release profiles showed that the release of associated LDC was slower than that of the free drug. Atomic force microscopy analyses showed that the spherical structure of the particles was preserved as a function of time, as well as after the release experiments. Cytotoxicity and pharmacological tests confirmed that association with the NSs reduced the toxicity of LDC, and prolonged its anesthetic action. This new formulation could potentially be used in applications requiring gradual anesthetic release, especially dental procedures. Copyright © 2012 Wiley Periodicals, Inc.

Effect of Nisin's Controlled Release on Microbial Growth as Modeled for Micrococcus luteus.

PubMed

Balasubramanian, Aishwarya; Lee, Dong Sun; Chikindas, Michael L; Yam, Kit L

2011-06-01

The need for safe food products has motivated food scientists and industry to find novel technologies for antimicrobial delivery for improving food safety and quality. Controlled release packaging is a novel technology that uses the package to deliver antimicrobials in a controlled manner and sustain antimicrobial stress on the targeted microorganism over the required shelf life. This work studied the effect of controlled release of nisin to inhibit growth of Micrococcus luteus (a model microorganism) using a computerized syringe pump system to mimic the release of nisin from packaging films which was characterized by an initially fast rate and a slower rate as time progressed. The results show that controlled release of nisin was strikingly more effective than instantly added ("formulated") nisin. While instant addition experiments achieved microbial inhibition only at the beginning, controlled release experiments achieved complete microbial inhibition for a longer time, even when as little as 15% of the amount of nisin was used as compared to instant addition.

A Release from Proactive Interference Analysis of Gender Schema Encoding for Occupations in Adults and Children

ERIC Educational Resources Information Center

Kee, D.W.; Gregory-Domingue, A.; Rice, K.; Tone, K.

2005-01-01

The present study examined gender schema encoding (activation of gender stereotypes) in the absence deliberate purposes relating to people (stereotype application). A release from proactive interference short-term-memory task was used. College (Experiment 1) and sixth-grade (Experiment 2) participants were asked to retain item identity and…

Early Academic Experiences of Recently Incarcerated African American Males

ERIC Educational Resources Information Center

Jeffers, Adam R.

2010-01-01

This project examines the early educational experiences of 6 young African American males (ages 18-25) who attended urban schools in San Diego, California. All 6 men were incarcerated for at least 1-year before participating in a pre-release program. The participants were part of a pre-release program in San Diego, California, which was selected…

CRRES combined radiation and release effects satellite program

NASA Technical Reports Server (NTRS)

Giles, B. L. (Compiler); Mccook, M. A. (Compiler); Mccook, M. W. (Compiler); Miller, G. P. (Compiler)

1995-01-01

The various regions of the magnetosphere-ionosphere system are coupled by flows of charged particle beams and electromagnetic waves. This coupling gives rise to processes that affect both technical and non-technical aspects of life on Earth. The CRRES Program sponsored experiments which were designed to produce controlled and known input to the space environment and the effects were measured with arrays of diagnostic instruments. Large amounts of material were used to modify and perturb the environment in a controlled manner, and response to this was studied. The CRRES and PEGSAT satellites were dual-mission spacecraft with a NASA mission to perform active chemical-release experiments, grouped into categories of tracer, modification, and simulation experiments. Two sounding rocket chemical release campaigns completed the study.

Lack of experience-based stratification in homing pigeon leadership hierarchies.

PubMed

Watts, Isobel; Pettit, Benjamin; Nagy, Máté; de Perera, Theresa Burt; Biro, Dora

2016-01-01

In societies that make collective decisions through leadership, a fundamental question concerns the individual attributes that allow certain group members to assume leadership roles over others. Homing pigeons form transitive leadership hierarchies during flock flights, where flock members are ranked according to the average time differences with which they lead or follow others' movement. Here, we test systematically whether leadership ranks in navigational hierarchies are correlated with prior experience of a homing task. We constructed experimental flocks of pigeons with mixed navigational experience: half of the birds within each flock had been familiarized with a specific release site through multiple previous releases, while the other half had never been released from the same site. We measured the birds' hierarchical leadership ranks, then switched the same birds' roles at a second site to test whether the relative hierarchical positions of the birds in the two subsets would reverse in response to the reversal in levels of experience. We found that while across all releases the top hierarchical positions were occupied by experienced birds significantly more often than by inexperienced ones, the remaining experienced birds were not consistently clustered in the top half-in other words, the network did not become stratified. We discuss our results in light of the adaptive value of structuring leadership hierarchies according to 'merit' (here, navigational experience).

Experience with the high-intensity sweetener saccharin impairs glucose homeostasis and GLP-1 release in rats

PubMed Central

Swithers, Susan E.; Laboy, Alycia F.; Clark, Kiely; Cooper, Stephanie; Davidson, T.L.

2012-01-01

Previous work from our lab has demonstrated that experience with high-intensity sweeteners in rats leads to increased food intake, body weight gain and adiposity, along with diminished caloric compensation and decreased thermic effect of food. These changes may occur as a result of interfering with learned relations between the sweet taste of food and the caloric or nutritive consequences of consuming those foods. The present experiments determined whether experience with the high-intensity sweetener saccharin versus the caloric sweetener glucose affected blood glucose homeostasis. The results demonstrated that during oral glucose tolerance tests, blood glucose levels were more elevated in animals that had previously consumed the saccharin-sweetened supplements. In contrast, during glucose tolerance tests when a glucose solution was delivered directly into the stomach, no differences in blood glucose levels between the groups were observed. Differences in oral glucose tolerance responses were not accompanied by differences in insulin release; insulin release was similar in animals previously exposed to saccharin and those previously exposed to glucose. However, release of GLP-1 in response to an oral glucose tolerance test, but not to glucose tolerance tests delivered by gavage, was significantly lower in saccharin-exposed animals compared to glucose-exposed animals. Differences in both blood glucose and GLP-1 release in saccharin animals were rapid and transient, and suggest that one mechanism by which exposure to high-intensity sweeteners that interfere with a predictive relation between sweet tastes and calories may impair energy balance is by suppressing GLP-1 release, which could alter glucose homeostasis and reduce satiety. PMID:22561130

2169 steel waveform experiments.

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

Furnish, Michael David; Alexander, C. Scott; Reinhart, William Dodd

2012-11-01

In support of LLNL efforts to develop multiscale models of a variety of materials, we have performed a set of eight gas gun impact experiments on 2169 steel (21% Cr, 6% Ni, 9% Mn, balance predominantly Fe). These experiments provided carefully controlled shock, reshock and release velocimetry data, with initial shock stresses ranging from 10 to 50 GPa (particle velocities from 0.25 to 1.05 km/s). Both windowed and free-surface measurements were included in this experiment set to increase the utility of the data set, as were samples ranging in thickness from 1 to 5 mm. Target physical phenomena included themore » elastic/plastic transition (Hugoniot elastic limit), the Hugoniot, any phase transition phenomena, and the release path (windowed and free-surface). The Hugoniot was found to be nearly linear, with no indications of the Fe phase transition. Releases were non-hysteretic, and relatively consistent between 3- and 5-mmthick samples (the 3 mm samples giving slightly lower wavespeeds on release). Reshock tests with explosively welded impactors produced clean results; those with glue bonds showed transient releases prior to the arrival of the reshock, reducing their usefulness for deriving strength information. The free-surface samples, which were steps on a single piece of steel, showed lower wavespeeds for thin (1 mm) samples than for thicker (2 or 4 mm) samples. A configuration used for the last three shots allows release information to be determined from these free surface samples. The sample strength appears to increase with stress from ~1 GPa to ~ 3 GPa over this range, consistent with other recent work but about 40% above the Steinberg model.« less

Use of a nanoporous biodegradable miniature device to regulate cytokine release for cancer treatment

PubMed Central

He, Hongyan; Grignol, Valerie; Karpa, Volodymyr; Yen, Chi; LaPerle, Krista; Zhang, Xiaoli; Jones, Natalie B.; Liang, Margaret I.; Lesinski, Gregory B.; Ho, W.S. Winston; Carson, William E.; Lee, L. James

2014-01-01

The clinical management of locally recurrent or unresectable malignant melanoma continues to pose a significant challenge. These lesions are typically painful and currently available treatments, such as repeated intratumoral injections of interferon-alpha (IFN-α), are costly and inconvenient. Nanotechnology offers promise as a novel means of drug delivery. A capsule-like nanoporous miniature device (NMD) based on a biodegradable polymer, poly(polycaprolactone) (PCL) was developed for controlling the local delivery of immunological agents to the tumor microenvironment. The device consists of a nanoporous release gate, a fabricated drug reservoir loaded with IFN-α and a protective layer. To improve the biocompatibility of the device, a hydrophilic poly(ethylene glycol) monoacrylate was applied to the outside wall of the device via covalent bonding techniques. Microscopic visualization of the nanoporous gate from in vitro experiments exhibited good pore stability over a two-month period. In vitro experiments demonstrated a constant release rate of IFN-α from the NMD and showed that the release rate could be regulated by the gate area. The released IFN-α was biologically functional. Cytokine-containing supernatants from release experiments phosphorylated signal transducer and activator of transcription (STAT1) in peripheral blood mononuclear cells. Subcutaneous implantation of the NMDs was well tolerated and associated with an anti-tumor effect in a human xenograft model of melanoma. There was no evidence of a significant inflammatory response to the NMD or encapsulation of the NMD by fibrosis. These experiments show that the NMD can be fabricated and employed in vivo as a versatile drug delivery platform. PMID:21362447

A mathematical model for the release of noble gas and Cs from porous nuclear fuel based on VEGA 1&2 experiments

NASA Astrophysics Data System (ADS)

Simones, M. P.; Reinig, M. L.; Loyalka, S. K.

2014-05-01

Release of fission products from nuclear fuel in accidents is an issue of major concern in nuclear reactor safety, and there is considerable room for development of improved models, supported by experiments, as one needs to understand and elucidate role of various phenomena and parameters. The VEGA (Verification Experiments of radionuclides Gas/Aerosol release) program on several irradiated nuclear fuels investigated the release rates of radionuclides and results demonstrated that the release rates of radionuclides from all nuclear fuels tested decreased with increasing external gas pressure surrounding the fuel. Hidaka et al. (2004-2011) accounted for this pressure effect by developing a 2-stage diffusion model describing the transport of radionuclides in porous nuclear fuel. We have extended this 2-stage diffusion model to account for mutual binary gas diffusion in the open pores as well as to introduce the appropriate parameters to cover the slip flow regime (0.01 ⩽ Kn ⩽ 0.1). While we have directed our numerical efforts toward the simulation of the VEGA experiments and assessments of differences from the results of Hidaka et al., the model and the techniques reported here are of larger interest as these would aid in modeling of diffusion in general (e.g. in graphite and other nuclear materials of interest).

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

Luna, R. E.

This paper provides a simple model for estimating the release of respirable aerosols resulting from an attack on a spent fuel cask using a high energy density device (HEDD). Two primary experiments have provided data on potential releases from spent fuel casks under HEDD attack. Sandia National Laboratories (SNL) conducted the first in the early 1980's and the second was sponsored by Gessellshaft fur Anlagen- and Reaktorsicherheit (GRS) in Germany and conducted in France in 1994. Both used surrogate spent fuel assemblies in real casks. The SNL experiments used un-pressurized fuel pin assemblies in a single element cask while themore » GRS tests used pressurized fuel pin assemblies in a 9-element cask. Data from the two test programs is reasonably consistent, given the differences in the experiments, but the use of the test data for prediction of releases resulting from HEDD attack requires a method for accounting for the effects of pin pressurization release and the ratio of pin plenum gas release to cask free volume (VR). To account for the effects of VR and to link the two data sources, a simple model has been developed that uses both the SNL data and the GRS data as well as recent test data on aerosols produced in experiments with single pellets subjected to HEDD effects conducted under the aegis of the International Consortium's Working Group on Sabotage of Transport and Storage Casks (WGSTSC). (authors)« less

Release and fate of fluorocarbons in a shredder residue landfill cell: 1. Laboratory experiments.

PubMed

Scheutz, Charlotte; Fredenslund, Anders M; Nedenskov, Jonas; Kjeldsen, Peter

2010-11-01

The shredder residues from automobiles, home appliances and other metal-containing products are often disposed in landfills, as recycling technologies for these materials are not common in many countries. Shredder waste contains rigid and soft foams from cushions and insulation panels blown with fluorocarbons. The objective of this study was to use laboratory experiments to estimate fluorocarbon release and attenuation processes in a monofill shredder residue (SR) landfill cell. Waste from the open SR landfill cell at the AV Miljø landfill in Denmark was sampled at three locations. The waste contained 1-3% metal and a relatively low fraction of rigid polyurethane (PUR) foam particles. The PUR waste contained less blowing agent (CFC-11) than predicted from a release model. However, CFC-11 was steadily released in an aerobic bench scale experiment. Anaerobic waste incubation bench tests showed that SRSR produced significant methane (CH(4)), but at rates that were in the low end of the range observed for municipal solid waste. Aerobic and anaerobic batch experiments showed that processes in SRSR potentially can attenuate the fluorocarbons released from the SRSR itself: CFC-11 is degraded under anaerobic conditions with the formation of degradation products, which are being degraded under CH(4) oxidation conditions prevailing in the upper layers of the SR. Copyright © 2010 Elsevier Ltd. All rights reserved.

Influence of environmental parameters and of their interactions on the release of metal(loid)s from a construction material in hydraulic engineering.

PubMed

Schmukat, A; Duester, L; Goryunova, E; Ecker, D; Heininger, P; Ternes, T A

2016-03-05

Besides the leaching behaviour of a construction material under standardised test-specific conditions with laboratory water, for some construction materials it is advisable to test their environmental behaviour also under close to end use conditions. The envisaged end use combined with the product characteristics (e.g. mineral phases) is decisive for the choice of environmental factors that may change the release of substance that potentially cause adverse environmental effects (e.g. fertilisation or ecotoxicity). At the moment an experimental link is missing between mono-factorial standardised test systems and non standardised complex incubation experiments such as mesocosms which are closer to environmental conditions. Multi-factorial batch experiments may have the potential to close the gap. To verify this, batch experiments with copper slag were performed which is used as armour stones in hydraulic engineering. Design of experiments (DoE) was applied to evaluate the impact of pH, ionic strength, temperature and sediment content on the release of As, Cu, Mo, Ni, Pb, Sb and Zn. The study shows that release and sediment-eluent partitioning of metal(loid)s are impacted by interactions between the studied factors. Under the prevalent test conditions sediment acts as a sink enhancing most strongly the release of elements from the material. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis and characterization of superabsorbent polymer prepared by radiation-induced graft copolymerization of acrylamide onto carboxymethyl cellulose for controlled release of agrochemicals

NASA Astrophysics Data System (ADS)

Hemvichian, Kasinee; Chanthawong, Auraruk; Suwanmala, Phiriyatorn

2014-10-01

Superabsorbent polymer (SAP) was synthesized by radiation-induced grafting of acrylamide (AM) onto carboxymethyl cellulose (CMC) in the presence of a crosslinking agent, N,N‧-methylenebisacrylamide (MBA). The effects of various parameters, such as dose, the amount of CMC, AM, MBA and ionic strength on the swelling ratio were investigated. In order to evaluate its controlled release potential, SAP was loaded with potassium nitrate (KNO3) as an agrochemical model and its potential for controlled release of KNO3 was studied. The amount of released KNO3 was analyzed by an inductively coupled plasma mass spectrometry (ICP-MS). The results from controlled release experiment agreed very well with the results from swelling experiment. The synthesized SAP was characterized by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The obtained SAP exhibited a swelling ratio of 190 g/g of dry gel.

p-Coumaric Acid Attenuates UVB-Induced Release of Stratifin from Keratinocytes and Indirectly Regulates Matrix Metalloproteinase 1 Release from Fibroblasts

PubMed Central

Seok, Jin Kyung

2015-01-01

Ultraviolet (UV) radiation-induced loss of dermal extracellular matrix is associated with skin photoaging. Recent studies demonstrated that keratinocyte-releasable stratifin (SFN) plays a critical role in skin collagen metabolism by inducing matrix metalloproteinase 1 (MMP1) expression in target fibroblasts. In the present study, we examined whether SFN released from UVB-irradiated epidermal keratinocytes increases MMP1 release from dermal fibroblasts, and whether these events are affected by p-coumaric acid (p-CA), a natural phenolic compound with UVB-shielding and antioxidant properties. HaCaT cells were exposed to UVB in the absence and presence of p-CA, and the conditioned medium was used to stimulate fibroblasts in medium transfer experiments. The cells and media were analyzed to determine the expressions/releases of SFN and MMP1. UVB exposure increased SFN release from keratinocytes into the medium. The conditioned medium of UVB-irradiated keratinocytes increased MMP1 release from fibroblasts. The depletion of SFN using a siRNA rendered the conditioned medium of UVB-irradiated keratinocytes ineffective at stimulating fibroblasts to release MMP1. p-CA mitigated UVB-induced SFN expression in keratinocytes, and attenuated the MMP1 release by fibroblasts in medium transfer experiments. In conclusion, the present study demonstrated that the use of UV absorbers such as p-CA would reduce UV-induced SFN-centered signaling events involved in skin photoaging. PMID:25954129

p-Coumaric Acid Attenuates UVB-Induced Release of Stratifin from Keratinocytes and Indirectly Regulates Matrix Metalloproteinase 1 Release from Fibroblasts.

PubMed

Seok, Jin Kyung; Boo, Yong Chool

2015-05-01

Ultraviolet (UV) radiation-induced loss of dermal extracellular matrix is associated with skin photoaging. Recent studies demonstrated that keratinocyte-releasable stratifin (SFN) plays a critical role in skin collagen metabolism by inducing matrix metalloproteinase 1 (MMP1) expression in target fibroblasts. In the present study, we examined whether SFN released from UVB-irradiated epidermal keratinocytes increases MMP1 release from dermal fibroblasts, and whether these events are affected by p-coumaric acid (p-CA), a natural phenolic compound with UVB-shielding and antioxidant properties. HaCaT cells were exposed to UVB in the absence and presence of p-CA, and the conditioned medium was used to stimulate fibroblasts in medium transfer experiments. The cells and media were analyzed to determine the expressions/releases of SFN and MMP1. UVB exposure increased SFN release from keratinocytes into the medium. The conditioned medium of UVB-irradiated keratinocytes increased MMP1 release from fibroblasts. The depletion of SFN using a siRNA rendered the conditioned medium of UVB-irradiated keratinocytes ineffective at stimulating fibroblasts to release MMP1. p-CA mitigated UVB-induced SFN expression in keratinocytes, and attenuated the MMP1 release by fibroblasts in medium transfer experiments. In conclusion, the present study demonstrated that the use of UV absorbers such as p-CA would reduce UV-induced SFN-centered signaling events involved in skin photoaging.

Smectite clays in Mars soil - Evidence for their presence and role in Viking biology experimental results

NASA Technical Reports Server (NTRS)

Banin, A.; Rishpon, J.

1979-01-01

Evidence for the presence of smectite clays in Martian soils is reviewed and results of experiments with certain active clays simulating the Viking biology experiments are reported. Analyses of Martian soil composition by means of X-ray fluorescence spectrometry and dust storm spectroscopy and Martian geological history strongly suggest the presence of a mixture of weathered ferro-silicate minerals, mainly nontronite and montmorillonite, accompanied by soluble sulphate salts, as major constituents. Samples of montmorillonite and nontronite incubated with (C-14)-formate or the radioactive nutrient medium solution used in the Viking Labeled Release experiment, were found to produce patterns of release of radioactive gas very similar to those observed in the Viking experiments, indicating the iron-catalyzed decomposition of formate as the reaction responsible for the Viking results. The experimental results of Hubbard (1979) simulating the results of the Viking Pyrolytic Release experiment using iron montmorillonites are pointed out, and it is concluded that many of the results of the Viking biology experiments can be explained in terms of the surface activity of smectite clays in catalysis and adsorption.

Trigger, an active release experiment that stimulated auroral particle precipitation and wave emissions

NASA Technical Reports Server (NTRS)

Holmgren, G.; Bostroem, R.; Kelley, M. C.; Kintner, P. M.; Lundin, R.; Fahleson, U. V.; Bering, E. A.; Sheldon, W. R.

1979-01-01

The experiment design, including a description of the diagnostic and chemical release payload, and the general results are given for an auroral process simulation experiment. A drastic increase of the field aligned charged particle flux was observed over the approximate energy range 10 eV to more than 300 keV, starting about 150 ms after the release and lasting about one second. The is evidence of a second particle burst, starting one second after the release and lasting for tens of seconds, and evidence for a periodic train of particle bursts occurring with a 7.7 second period from 40 to 130 seconds after the release. A transient electric field pulse of 200 mv/m appeared just before the particle flux increase started. Electrostatic wave emissions around 2 kHz, as well as a delayed perturbation of the E-region below the plasma cloud were also observed. Some of the particle observations are interpreted in terms of field aligned electrostatic acceleration a few hundred kilometers above the injected plasma cloud. It is suggested that the acceleration electric field was created by an instability driven by field aligned currents originating in the plasma cloud.

Unsaturated flow and transport through a fault embedded in fractured welded tuff

USGS Publications Warehouse

Salve, Rohit; Liu, Hui‐Hai; Cook, Paul; Czarnomski, Atlantis; Hu, Qinhong; Hudson, David

2004-01-01

To evaluate the importance of matrix diffusion as a mechanism for retarding radionuclide transport in the vicinity of a fault located in unsaturated fractured rock, we carried out an in situ field experiment in the Exploratory Studies Facility at Yucca Mountain, Nevada. This experiment involved the release of ∼82,000 L of water over a period of 17 months directly into a near‐vertical fault under both constant positive head (at ∼0.04 m) and decreasing fluxes. A mix of conservative tracers (pentafluorobenzoic acid (PFBA) and bromide (applied in the form of lithium bromide)) was released along the fault over a period of 9 days, 7 months after the start of water release along the fault. As water was released into the fault, seepage rates were monitored in a large cavity excavated below the test bed. After the release of tracers, seepage water was continuously collected from three locations and analyzed for the injected tracers. Observations of bromide concentrations in seepage water during the early stages of the experiment and bromide and PFBA concentrations in the seepage water indicate the significant effects of matrix diffusion on transport through a fault embedded in fractured, welded rock.

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

None

This document contains a listing, description, and selected references for documented human radiation experiments sponsored, supported, or performed by the US Department of Energy (DOE) or its predecessors, including the US Energy Research and Development Administration (ERDA), the US Atomic Energy Commission (AEC), the Manhattan Engineer District (MED), and the Off ice of Scientific Research and Development (OSRD). The list represents work completed by DOE`s Off ice of Human Radiation Experiments (OHRE) through June 1995. The experiment list is available on the Internet via a Home Page on the World Wide Web (http://www.ohre.doe.gov). The Home Page also includes the fullmore » text of Human Radiation Experiments. The Department of Energy Roadmap to the Story and the Records (DOE/EH-0445), published in February 1995, to which this publication is a supplement. This list includes experiments released at Secretary O`Leary`s June 1994 press conference, as well as additional studies identified during the 12 months that followed. Cross-references are provided for experiments originally released at the press conference; for experiments released as part of The DOE Roadmap; and for experiments published in the 1986 congressional report entitled American Nuclear Guinea Pigs: Three Decades of Radiation Experiments on US Citizens. An appendix of radiation terms is also provided.« less

Effects of temperature and photoperiod on lure display and glochidial release in a freshwater mussel

Treesearch

Andrew M. Gascho-Landis; Tyler L. Mosley; Wendell R. Haag; James A. Stoeckel

2012-01-01

Freshwater mussels use an array of strategies to transfer their parasitic larvae (glochidia) to fish hosts. We examined the effects of temperature, photoperiod, and female gravidity on mantle lure display and conglutinate release by Ligumia subrostrata (Say, 1831) in 2 laboratory experiments. In the 1st experiment, we examined the use of these strategies in 4...

Short- and long-term releases of fluorocarbons from disposal of polyurethane foam waste.

PubMed

Kjeldsen, Peter; Scheutz, Charlotte

2003-11-01

Several halocarbons having very high global warming or ozone depletion potentials have been used as a blowing agent (BA) for insulation foam in home appliances, such as refrigerators and freezers. Many appliances are shredded after the end of their useful life. Release experiments carried out in the laboratory on insulation foam blown with the blowing agents CFC-11, HCFC-141b, HCF-134fa, and HFC-245fa revealed that not all blowing agents are released during a 6-week period following the shredding process. The experiments confirmed the hypothesis that the release could be divided into three segments: By shredding foam panels, a proportion of the closed cells is either split or damaged to a degree allowing for a sudden release of the contained atmosphere in the cell (the instantaneous release). Cells adjacent to the cut surface may be only slightly damaged by tiny cracks or holes allowing a relative slow release of the BA to the surroundings (the short-term release). A significant portion of the cells in the foam particle will be unaffected and only allows release governed by slow diffusion through the PUR cell wall (the long-term release). The magnitude of the releases is for all three types highly dependent on how fine the foam is shredded. The residual blowing agent remaining after the 6-week period may be very slowly released if the integrity of the foam particles with respect to diffusion properties is kept after disposal of the foam waste on landfills. It is shown by setting up a national model simulating the BA releases following decommissioning of used domestic refrigerators/freezers in the United States that the release patterns are highly dependent on how the appliances are shredded.

Multilevel challenges to engagement in HIV care after prison release: a theory-informed qualitative study comparing prisoners' perspectives before and after community reentry.

PubMed

Haley, Danielle F; Golin, Carol E; Farel, Claire E; Wohl, David A; Scheyett, Anna M; Garrett, Jenna J; Rosen, David L; Parker, Sharon D

2014-12-09

Although prison provides the opportunity for HIV diagnosis and access to in-prison care, following release, many HIV-infected inmates experience clinical setbacks, including nonadherence to antiretrovirals, elevations in viral load, and HIV disease progression. HIV-infected former inmates face numerous barriers to successful community reentry and to accessing healthcare. However, little is known about the outcome expectations of HIV-infected inmates for release, how their post-release lives align with pre-release expectations, and how these processes influence engagement in HIV care following release from prison. We conducted semi-structured interviews (24 pre- and 13 post-release) with HIV-infected inmates enrolled in a randomized controlled trial of a case management intervention to enhance post-release linkage to care. Two researchers independently coded data using a common codebook. Intercoder reliability was strong (kappa = 0.86). We analyzed data using Grounded Theory methodology and Applied Thematic Analysis. We collected and compared baseline sociodemographic and behavioral characteristics of all cohort participants who did and did not participate in the qualitative interviews using Fisher's Exact Tests for categorical measures and Wilcoxon rank-sum tests for continuous measures. Most participants were heterosexual, middle-aged, single, African American men and women with histories of substance use. Substudy participants were more likely to anticipate living with family/friends and needing income assistance post-release. Most were taking antiretrovirals prior to release and anticipated needing help securing health benefits and medications post-release. Before release, most participants felt confident they would be able to manage their HIV. However, upon release, many experienced intermittent or prolonged periods of antiretroviral nonadherence, largely due to substance use relapse or delays in care initiation. Substance use was precipitated by stressful life experiences, including stigma, and contact with drug-using social networks. As informed by the Social Cognitive Theory and HIV Stigma Framework, findings illustrate the reciprocal relationships among substance use, experiences of stigma, pre- and post-release environments, and skills needed to engage in HIV care. These findings underscore the need for comprehensive evidence-based interventions to prepare inmates to transition from incarceration to freedom, particularly those that strengthen linkage to HIV care and focus on realities of reentry, including stigma, meeting basic needs, preventing substance abuse, and identifying community resources.

The relationship of body size to survivorship of hatchling snapping turtles (Chelydra serpentina): an evaluation of the "bigger is better" hypothesis.

PubMed

Congdon, Justin D; Nagle, Roy D; Dunham, Arthur E; Beck, Chirstopher W; Kinney, Owen M; Yeomans, S Rebecca

1999-11-01

In many organisms, body size is positively correlated with traits that are presumably related to fitness. If directional selection frequently favors larger offspring (the "bigger is better" hypothesis), the results of such selection should be detectable with field experiments. We tested the "bigger is better" hypothesis in hatchling snapping turtles (Chelydra serpentina) by conducting one long-term and three short-term experiments on the University of Michigan E.S. George Reserve in southeastern Michigan. In the fall of 1995 and 1996, we released hatchlings at artificial nests separated from the nearest wetland by fences. We recorded the proportion of hatchlings recaptured, the time it took hatchlings to move to fences from artificial nests 45, 55, and 80 m away, and dispersion along the fence. We determined whether the response variables and probability of recapture at fences were associated with hatchling body size. During 1995, average travel times of hatchlings from the experimental nests were not related to distance from the fence; however, time to recapture was positively correlated with dispersion from the zero point on the fence, and the maximum time to reach the fence was almost twice as long for hatchlings from the 80-m nest compared to those from the 45-m nest. Sixty-seven percent of the hatchlings reached the fence and the proportions doing so from each nest were not different. Body size was not significantly related to probability of recapture in either of the 1995 experiments. In 1996, 59% of released hatchlings were recaptured. Time to recapture was not related to dispersion from the zero point or to body size. Cubic spline analysis suggested stabilizing selection on body size. We also conducted a set of long-term hatchling release experiments between 1980-1993 to compare the survival of hatchlings released at nest sites to that of hatchlings released directly into marshes, and we looked for relationships between survivorship and hatchling body size. During 7 years in which more than 30 hatchlings were released, 413 hatchlings were released directly into the marsh and 262 were released at nests: their probability of survival did not differ. Over all years, for both release groups combined and for each group separately, survival was not related to body size. In 1983 alone, survival was also not related to body size for either group or for both groups combined. In our three short-term experiments and one long-term experiment, we found no evidence to support the "bigger is better" hypothesis. When selection on body size did occur, selection was stabilizing, not directional for larger size.

Pyroclast acceleration and energy partitioning in fake explosive eruptions

NASA Astrophysics Data System (ADS)

Gaudin, Damien; Taddeucci, Jacopo; Scheu, Bettina; Valentine, Greg; Capponi, Antonio; Kueppers, Ulrich; Graettiger, Allison; Sonder, Ingo

2014-05-01

Explosive eruptions are characterized by the fast release of energy, with gas expansion playing a lead role. An excess of pressure may be generated either by the exsolution and accumulation of volatiles (e.g., vulcanian and strombolian explosions) or by in situ vaporization of water (e.g., phreato-magmatic explosions). The release of pressurized gas ejects magma and country rock pyroclasts at velocities that can reach several hundred of meters per second. The amount and velocity of pyroclasts is determined not only by the total released energy, but also by the system-specific dynamics of the energy transfer from gas to pyroclasts. In this context, analogue experiments are crucial, since the amount of available energy is determined. Here, we analyze three different experiments, designed to reproduce different aspects of explosive volcanism, focusing on the acceleration phase of the pyroclasts, in order to compare how the potential energy is transferred to the pyroclasts in different systems. In the first, shock-tube-type experiment, salt crystals resting in a pressurized Plexiglas cylinder are accelerated when a diaphragm set is suddenly opened, releasing the gas. In the second experiment, a pressurized air bubble is released in a water-filled Plexiglas pipe; diaphragm opening causes sudden expansion and bursting of the bubble and ejection of water droplets. In the last experiment, specifically focusing on phreatomagmatic eruptions, buried explosive charges accelerate the overlying loose material. All experiments were monitored by multiple high speed cameras and a variety of sensors. Despite the largely differing settings and processes, particle ejection velocity above the vent from the three experiments share a non-linear decay over time. Fitting this decay allows to estimate a characteristic depth that is related to the specific acceleration processes. Given that the initial available energy is experimentally controlled a priori, the information on the acceleration processes (and related kinetic energy) can be used to brings new constraints on the energy partition and general pyroclasts ejection mechanisms during eruptions.

Field and laboratory investigations of inactivation of viruses (PRD1 and MS2) attached to iron oxide-coated quartz san

USGS Publications Warehouse

Ryan, Joseph N.; Harvey, Ronald W.; Metge, David W.; Elimelech, Menachem; Navigato, Theresa; Pieper, Ann P.

2002-01-01

Field and laboratory experiments were conducted to investigate inactivation of viruses attached to mineral surfaces. In a natural gradient transport field experiment, bacteriophage PRD1, radiolabeled with 32P, was injected into a ferric oxyhydroxide-coated sand aquifer with bromide and linear alkylbenzene sulfonates. In a zone of the aquifer contaminated by secondary sewage infiltration, small fractions of infective and 32P-labeled PRD1 broke through with the bromide tracer, followed by the slow release of 84% of the 32P activity and only 0.011% of the infective PRD1. In the laboratory experiments, the inactivation of PRD1, labeled with 35S (protein capsid), and MS2, dual radiolabeled with 35S (protein capsid) and 32P (nucleic acid), was monitored in the presence of groundwater and sediment from the contaminated zone of the field site. Release of infective viruses decreased at a much faster rate than release of the radiolabels, indicating that attached viruses were undergoing surface inactivation. Disparities between 32P and35S release suggest that the inactivated viruses were released in a disintegrated state. Comparison of estimated solution and surface inactivation rates indicates solution inactivation is ∼3 times as fast as surface inactivation. The actual rate of surface inactivation may be substantially underestimated owing to slow release of inactivated viruses.

Microbial Mineral Weathering for Nutrient Acquisition Releases Arsenic

NASA Astrophysics Data System (ADS)

Mailloux, B. J.; Alexandrova, E.; Keimowitz, A.; Wovkulich, K.; Freyer, G.; Stolz, J.; Kenna, T.; Pichler, T.; Polizzotto, M.; Dong, H.; Radloff, K. A.; van Geen, A.

2008-12-01

Tens of millions of people in Southeast Asia drink groundwater contaminated with naturally occurring arsenic. The process of arsenic release from the sediment to the groundwater remains poorly understood. Experiments were performed to determine if microbial mineral weathering for nutrient acquisition can serve as a potential mechanism for arsenic mobilization. We performed microcosm experiments with Burkholderia fungorum, phosphate free artificial groundwater, and natural apatite. Controls included incubations with no cells and with killed cells. Additionally, samples were treated with two spikes - an arsenic spike, to show that arsenic release is independent of the initial arsenic concentration, and a phosphate spike to determine whether release occurs at field relevant phosphate conditions. We show in laboratory experiments that phosphate-limited cells of Burkholderia fungorum mobilize ancillary arsenic from apatite as a by-product of mineral weathering for nutrient acquisition. The released arsenic does not undergo a redox transformation but appears to be solubilized from the apatite mineral lattice as arsenate during weathering. Apatite has been shown to be commonly present in sediment samples from Bangladesh aquifers. Analysis of apatite purified from the Ganges, Brahamputra, Meghna drainage basin shows 210 mg/kg of arsenic, which is higher than the average crustal level. Finally, we demonstrate the presence of the microbial phenotype that releases arsenic from apatite in Bangladesh sediments. These results suggest that microbial weathering for nutrient acquisition could be an important mechanism for arsenic mobilization.

Probing the magnetosphere using chemical releases from the Combined Release and Radiation Effects Satellite

NASA Technical Reports Server (NTRS)

Bernhardt, P. A.

1992-01-01

An overview is presented of the chemical release experiments from NASA's Combined Release and Radiation Effects Satellite (CRRES) program. Preliminary results are given for the CRRES investigations of (1) stimulated electron and ion precipitation, (2) ion transport in the magnetotail, (3) critical ionization velocity, (4) field line tracing and parallel acceleration, (5) diamagnetic cavity formation and collapse, and (6) plasma instabilities. The chemical vapor properties from a thermite release mechanism are also briefly described.

Delivery of DNA vaccines by agarose hydrogel implants facilitates genetic immunization in cattle.

PubMed

Toussaint, J F; Dubois, A; Dispas, M; Paquet, D; Letellier, C; Kerkhofs, P

2007-01-26

The present study demonstrates the interest of two slow-release systems as vaccination tools in cattle. Two experiments show that a first intradermal administration of one DNA vaccine dose combined with the slow-release of a second dose conduct to a priming of the bovine herpesvirus 1-specific immune response similar to the one generated by two discrete administrations 4 weeks apart. The first experiment demonstrates the efficacy of the slow-release system with well-characterized Alzet osmotic pumps, whereas the second experiment extends the same concept with innovative agarose hydrogel implants. These latter implants are cheaper and more convenient than the osmotic pumps or repeated intradermal administrations since they contribute to an efficient priming of the immune response in a single manipulation of the animals.

Development of an Airborne Micropulse Water Vapor DIAL

NASA Astrophysics Data System (ADS)

Nehrir, A. R.; Ismail, S.

2012-12-01

Water vapor plays a key role in many atmospheric processes affecting both weather and climate. Airborne measurements of tropospheric water vapor profiles have been a longstanding observational need to not only the active remote sensing community but also to the meteorological, weather forecasting, and climate/radiation science communities. Microscale measurements of tropospheric water vapor are important for enhancing near term meteorological forecasting capabilities while mesoscale and synopticscale measurements can lead to an enhanced understanding of the complex coupled feedback mechanisms between water vapor, temperature, aerosols, and clouds. To realize tropospheric measurements of water vapor profiles over the microscale-synopticscale areas of meteorological interest, a compact and cost effective airborne micropulse differential absorption lidar (DIAL) is being investigated using newly emerging semiconductor based laser technology. Ground based micropulse DIAL (MPD) measurements of tropospheric water vapor and aerosol profiles up to 6 km and 15 km, respectively, have been previously demonstrated using an all semiconductor based laser transmitter. The DIAL transmitter utilizes a master oscillator power amplifier (MOPA) configuration where two semiconductor seed lasers are used to seed a single pass traveling wave tapered semiconductor optical amplifier (TSOA), producing up to 7μJ pulse energies over a 1 μs pulse duration at a 10 kHz pulse repetition frequency (PRF). Intercomparisons between the ground based instrument measurements and radiosonde profiles demonstrating the MPD performance under varying atmospheric conditions will be presented. Work is currently ongoing to expand upon the ground based MPD concept and to develop a compact and cost effective system capable of deployment on a mid-low altitude aircraft such as the NASA Langley B200 King Air. Initial lab experiments show that a two-three fold increase in the laser energy compared to the ground based instrument is achievable via overdriven current pulses to the TSOA gain medium while maintaining a 1μs and 10 kHz pulse width and PRF, respectively. The increase in the laser transmitter pulse energy will allow for nighttime and daytime water vapor profile retrievals from an airborne platform operating at an 8 km altitude with 2-5 minute integration periods. Results from a numerical model demonstrating the performance of an airborne DIAL system with the mentioned transmitter enhancements will be presented and compared against the existing ground based instrument performance. Furthermore, results from laboratory experiments demonstrating the laser transmitter performance including maximum extractable energy, energy stability, and spectral purity will also be presented.

Large-scale fiber release and equipment exposure experiments. [aircraft fires

NASA Technical Reports Server (NTRS)

Pride, R. A.

1980-01-01

Outdoor tests were conducted to determine the amount of fiber released in a full scale fire and trace its dissemination away from the fire. Equipment vulnerability to fire released fibers was assessed through shock tests. The greatest fiber release was observed in the shock tube where the composite was burned with a continuous agitation to total consumption. The largest average fiber length obtained outdoors was 5 mm.

Modulation of 3H-noradrenaline release by presynaptic opioid, cannabinoid and bradykinin receptors and β-adrenoceptors in mouse tissues

PubMed Central

Trendelenburg, A U; Cox, S L; Schelb, V; Klebroff, W; Khairallah, L; Starke, K

2000-01-01

Release-modulating opioid and cannabinoid (CB) receptors, β-adrenoceptors and bradykinin receptors at noradrenergic axons were studied in mouse tissues (occipito-parietal cortex, heart atria, vas deferens and spleen) preincubated with 3H-noradrenaline. Experiments using the OP1 receptor-selective agonists DPDPE and DSLET, the OP2-selective agonists U50488H and U69593, the OP3-selective agonist DAMGO, the ORL1 receptor-selective agonist nociceptin, and a number of selective antagonists showed that the noradrenergic axons innervating the occipito-parietal cortex possess release-inhibiting OP3 and ORL1 receptors, those innervating atria OP1, ORL1 and possibly OP3 receptors, and those innervating the vas deferens all four opioid receptor types. Experiments using the non-selective CB agonists WIN 55,212-2 and CP 55,940 and the CB1-selective antagonist SR 141716A indicated that the noradrenergic axons of the vas deferens possess release-inhibiting CB1 receptors. Presynaptic CB receptors were not found in the occipito-parietal cortex, in atria or in the spleen. Experiments using the non-selective β-adrenoceptor agonist isoprenaline and the β2-selective agonist salbutamol, as well as subtype-selective antagonists, demonstrated the occurrence of release-enhancing β2-adrenoceptors at the sympathetic axons of atria and the spleen, but demonstrated their absence in the occipito-parietal cortex and the vas deferens. Experiments with bradykinin and the B2-selective antagonist Hoe 140 showed the operation of release-enhancing B2 receptors at the sympathetic axons of atria, the vas deferens and the spleen, but showed their absence in the occipito-parietal cortex. The experiments document a number of new presynaptic receptor locations. They confirm and extend the existence of marked tissue and species differences in presynaptic receptors at noradrenergic neurons. PMID:10807669

Fluoride and phosphate release from carbonate-rich fluorapatite during managed aquifer recharge

NASA Astrophysics Data System (ADS)

Schafer, David; Donn, Michael; Atteia, Olivier; Sun, Jing; MacRae, Colin; Raven, Mark; Pejcic, Bobby; Prommer, Henning

2018-07-01

Managed aquifer recharge (MAR) is increasingly used as a water management tool to enhance water availability and to improve water quality. Until now, however, the risk of fluoride release during MAR with low ionic strength injectate has not been recognised or examined. In this study we analyse and report the mobilisation of fluoride (up to 58 μM) and filterable reactive phosphorus (FRP) (up to 55 μM) during a field groundwater replenishment experiment in which highly treated, deionised wastewater (average TDS 33 mg/L) was injected into a siliciclastic Cretaceous aquifer. In the field experiment, maximum concentrations, which coincided with a rise in pH, exceeded background groundwater concentrations by an average factor of 3.6 for fluoride and 24 for FRP. The combined results from the field experiment, a detailed mineralogical characterisation and geochemical modelling suggested carbonate-rich fluorapatite (CFA: Ca10(PO4)5(CO3,F)F2) to be the most likely source of fluoride and phosphate release. An anoxic batch experiment with powdered CFA-rich nodules sourced from the target aquifer and aqueous solutions of successively decreasing ionic strength closely replicated the field-observed fluoride and phosphate behaviour. Based on the laboratory experiment and geochemical modelling, we hypothesise that the release of fluoride and phosphate results from the incongruent dissolution of CFA and the simultaneous formation of a depleted layer that has hydrated di-basic calcium phosphate (CaHPO4·nH2O) composition at the CFA-water interface. Disequilibrium caused by calcium removal following breakthrough of the deionised injectate triggered the release of fluoride and phosphate. Given the increasing use of highly treated, deionised water for MAR and the ubiquitous presence of CFA and fluorapatite (Ca10(PO4)6F2) in aquifer settings worldwide, the risk of fluoride and phosphate release needs to be considered in the MAR design process.

Masking release by combined spatial and masker-fluctuation effects in the open sound field.

PubMed

Middlebrooks, John C

2017-12-01

In a complex auditory scene, signals of interest can be distinguished from masking sounds by differences in source location [spatial release from masking (SRM)] and by differences between masker-alone and masker-plus-signal envelopes. This study investigated interactions between those factors in release of masking of 700-Hz tones in an open sound field. Signal and masker sources were colocated in front of the listener, or the signal source was shifted 90° to the side. In Experiment 1, the masker contained a 25-Hz-wide on-signal band plus flanking bands having envelopes that were either mutually uncorrelated or were comodulated. Comodulation masking release (CMR) was largely independent of signal location at a higher masker sound level, but at a lower level CMR was reduced for the lateral signal location. In Experiment 2, a brief signal was positioned at the envelope maximum (peak) or minimum (dip) of a 50-Hz-wide on-signal masker. Masking was released in dip more than in peak conditions only for the 90° signal. Overall, open-field SRM was greater in magnitude than binaural masking release reported in comparable closed-field studies, and envelope-related release was somewhat weaker. Mutual enhancement of masking release by spatial and envelope-related effects tended to increase with increasing masker level.

[Effect of the interaction of microorganisms and iron oxides on arsenic releasing into groundwater in Chinese Loess].

PubMed

Xie, Yun-Yun; Chen, Tian-Hu; Zhou, Yue-Fei; Xie, Qiao-Qin

2013-10-01

A large part of groundwater in the Chinese Loess Plateau area is characterized by high arsenic concentration. Anaerobic bacteria have been considered to play key roles in promoting arsenic releasing from loess to groundwater. However, this hypothesis remains unconfirmed. Based on modeling experiments, this study investigated the speciation of arsenic in loess, and then determined the release rates and quantities of arsenic with the mediation of anaerobic bacteria. The results showed that arsenic contents in loess were between 23 mg.kg-1 and 30 mg.kg-1. No obvious arsenic content difference among loess samples was observed. The ratios for specific adsorbed, iron oxides co-precipitated and silicate co-precipitated arsenic were 37.76% , 36. 15% and 25. 69% , respectively. Indigenous microorganisms, dissimilatory iron reducing bacteria (DIRB) and sulfate reducing bacteria (SRB) could all promote the release of arsenic from loess. Organic matters highly affected the release rates. More than 100 mg.L-1 sodium lactate was required for all bacterial experiments to facilitate obvious arsenic release. Considering the redox condition in loess, the contribution of SRB to arsenic release in loess area was less feasible than that of DIRB and indigenous microorganisms.

Temperature and pressure determination of the tin melt boundary from a combination of pyrometry, spectral reflectance, and velocity measurements along release paths

NASA Astrophysics Data System (ADS)

La Lone, Brandon; Asimow, Paul; Fatyanov, Oleg; Hixson, Robert; Stevens, Gerald

2017-06-01

Plate impact experiments were conducted on tin samples backed by LiF windows to determine the tin melt curve. Thin copper flyers were used so that a release wave followed the 30-40 GPa shock wave in the tin. The release wave at the tin-LiF interface was about 300 ns long. Two sets of experiments were conducted. In one set, spectral emissivity was measured at six wavelengths using a flashlamp illuminated integrating sphere. In the other set, thermal radiance was measured at two wavelengths. The emissivity and thermal radiance measurements were combined to obtain temperature histories of the tin-LiF interface during the release. PDV was used to obtain stress histories. All measurements were combined to obtain temperature vs. stress release paths. A kink or steepening in the release paths indicate where the releases merge onto the melt boundary, and release paths originating from different shock stresses overlap on the melt boundary. Our temperature-stress release path measurements provide a continuous segment of the tin melt boundary that is in good agreement with some of the published melt curves. This work was done by National Security Technologies, LLC, under Contract No. DE-AC52-06NA25946 with the U.S. Department of Energy, and supported by the Site-Directed Research and Development Program. DOE/NV/259463133.

The influence of "host release factor" on carbon release by zooxanthellae isolated from fed and starved Aiptasia pallida (Verrill).

PubMed

Davy, S K; Cook, C B

2001-06-01

Symbiotic dinoflagellates (zooxanthellae) typically respond to extracts of host tissue with enhanced release of short-term photosynthetic products. We examined this "host release factor" (HRF) response using freshly isolated zooxanthellae of differing nutritional status. The nutritional status was manipulated by either feeding or starving the sea anemone Aiptasia pallida (Verrill). The release of fixed carbon from isolated zooxanthellae was measured using 14C in 30 min experiments. Zooxanthellae in filtered seawater alone released approximately 5% of photosynthate irrespective of host feeding history. When we used a 10-kDa ultrafiltrate of A. pallida host tissue as a source of HRF, approximately 14% of photosynthate was released to the medium. This increased to over 25% for zooxanthellae from anemones starved for 29 days or more. The cell-specific photosynthetic rate declined with starvation in these filtrate experiments, but the decline was offset by the increased percentage release. Indeed, the total amount of released photosynthate remained unchanged, or even increased, as zooxanthellae became more nutrient deficient. Similar trends were also observed when zooxanthellae from A. pallida were incubated in a 3-kDa ultrafiltrate of the coral Montastraea annularis, suggesting that HRF in the different filtrates operated in a similar manner. Our results support the suggestion that HRF diverts surplus carbon away from storage compounds to translocated compounds such as glycerol.

Sulphate release from construction and demolition material in soils

NASA Astrophysics Data System (ADS)

Abel, Stefan; Wessolek, Gerd

2013-04-01

In Berlin and many other cities soils are heavily influenced by anthropogenic activities and deposited substrates. A widespread technical substrate in technosols is construction and demolition material from residential and industrial buildings. Existing rubble landfills without sealing facilities pose threats to ground water quality. In the central city of Berlin rising sulphate concentrations of groundwaters (up to 1200 mg/L) are measured since more than two decades. Previous studies point out that the high sulphate concentrations are mainly attributed to World War II rubble. The major part of debris was deposited in form of landfills and contains approximately 0.3 wt% gypsum. The scope of our research is to determine mechanisms of sulphate release from debris material, interactions between sulphate release, soil hydraulic properties and potential sinks of sulphur. To estimate equilibrium concentration and kinetics of sulphate release of various debris components batch and column experiments are conducted. The same method is applied to determine potential adsorptive character of common debris components. To analyse the impacts of soil hydraulic properties on sulphate leaching we carry out soil column experiments with defined upper and lower boundary conditions, varying water flow velocity and induced preferential flow. Simultaneously we monitor sulphate concentration of soil leachate in a 2 m³ lysimeter. First results of the batch experiments show that gypsum from broken stucco is the main source of sulphate in the observed technosols. Other components as mortar and slag show a quite low sulphate release. Similar results are found within the column experiments. For brigs medium and strongly time dependent sulphate release is determined. Concentrations up to 1500 mg/L are measured in the soil leachate from the lysimeter.

Women Prisoners: A Survey of Their Work and Training Experiences in Custody and On Release. Home Office Research Study.

ERIC Educational Resources Information Center

Hamlyn, Becky; Lewis, Darren

Data from two surveys were gathered to inform recommendations on how to increase women prisoners' employability upon release in Great Britain. The first survey focused on 567 inmates' work experience and training prior to and during incarceration, as well as their expectations for life outside prison. About 33% of the women worked immediately…

The Lived Experiences of Single Hispanic Mothers Raising Gang-Affiliated Male Youth Released from Texas Juvenile Justice Department State Facilities: A Phenomenological Study

ERIC Educational Resources Information Center

Rodriguez-Almendarez, Ruby

2013-01-01

Purpose of the Study: The purpose of this transcendental phenomenological study (Moustakas, 1994) was to describe the experiences that single Hispanic mothers of gang-affiliated male juveniles face during their sons' reentry process after being released from a Texas Juvenile Justice Department state facility. Methods: After an extensive review of…

Listeners Experience Linguistic Masking Release in Noise-Vocoded Speech-in-Speech Recognition

ERIC Educational Resources Information Center

Viswanathan, Navin; Kokkinakis, Kostas; Williams, Brittany T.

2018-01-01

Purpose: The purpose of this study was to evaluate whether listeners with normal hearing perceiving noise-vocoded speech-in-speech demonstrate better intelligibility of target speech when the background speech was mismatched in language (linguistic release from masking [LRM]) and/or location (spatial release from masking [SRM]) relative to the…

Conditions affecting the release of phosphorus from surface lake sediments.

PubMed

Christophoridis, Christophoros; Fytianos, Konstantinos

2006-01-01

Laboratory studies were conducted to determine the effect of pH and redox conditions, as well as the effect of Fe, Mn, Ca, Al, and organic matter, on the release of ortho-phosphates in lake sediments taken from Lakes Koronia and Volvi (Northern Greece). Results were evaluated in combination with experiments to determine P fractionation in the sediment. The study revealed the major effect of redox potential and pH on the release of P from lake sediments. Both lakes showed increased release rates under reductive conditions and high pH values. The fractionation experiments revealed increased mobility of the reductive P fraction as well as of the NaOH-P fraction, indicating participation of both fractions in the overall release of sediment-bound P, depending on the prevailing environmental conditions. The results were assessed in combination with the release patterns of Fe, Mn, Ca, Al, and organic matter, enabling the identification of more specific processes of P release for each lake. The basic release patterns included the redox induced reductive dissolution of P-bearing metal oxides and the competitive exchange of phosphate anions with OH- at high pH values. The formation of an oxidized surface microlayer under oxic conditions acted as a protective film, preventing further P release from the sediments of Lake Volvi, while sediments from Lake Koronia exhibited a continuous and increased tendency to release P under various physicochemical conditions, acting as a constant source of internal P loading.

Building an Efficient Model for Afterburn Energy Release

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

Alves, S; Kuhl, A; Najjar, F

2012-02-03

Many explosives will release additional energy after detonation as the detonation products mix with the ambient environment. This additional energy release, referred to as afterburn, is due to combustion of undetonated fuel with ambient oxygen. While the detonation energy release occurs on a time scale of microseconds, the afterburn energy release occurs on a time scale of milliseconds with a potentially varying energy release rate depending upon the local temperature and pressure. This afterburn energy release is not accounted for in typical equations of state, such as the Jones-Wilkins-Lee (JWL) model, used for modeling the detonation of explosives. Here wemore » construct a straightforward and efficient approach, based on experiments and theory, to account for this additional energy release in a way that is tractable for large finite element fluid-structure problems. Barometric calorimeter experiments have been executed in both nitrogen and air environments to investigate the characteristics of afterburn for C-4 and other materials. These tests, which provide pressure time histories, along with theoretical and analytical solutions provide an engineering basis for modeling afterburn with numerical hydrocodes. It is toward this end that we have constructed a modified JWL equation of state to account for afterburn effects on the response of structures to blast. The modified equation of state includes a two phase afterburn energy release to represent variations in the energy release rate and an afterburn energy cutoff to account for partial reaction of the undetonated fuel.« less

Recent research on stishovite: Hugoniot and partial release Z experiments and DFT EOS calculations.

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

Furnish, Michael D.; Shulenburger, Luke; Desjarlais, Michael

We have conducted a series of ride-along experiments on the Z facility to ascertain the Hugoniot of silica centered in the stishovite phase over a range 0.4 - 1.0 TPa, together with partial release states produced at the interface between the sample and a fused silica window. The stishovite samples were synthesized in a large-volume multi-anvil press at 15 GPa and 1773 K, with an initial density of 4.29 gm/cc. The new Z experiments on stishovite fill in a gap between gas gun experiments and NIF experiments. The states are compared with the Hugoniots of quartz and fused silica formore » inferences as to EOS. They are generally consistent with Sesame 7360 predictions. Sound speed constraints from these data are discussed. The new Hugoniot data cross over the melting curve of stishovite; together with the partial-release data and predictions from density-functional theory modeling, they provide insights into the properties of solid and liquid under extreme conditions. These data are fundamentally important for understanding the interior of silicate-based super-Earths.« less

Artificial plasma experiments. Chemical release observations associated with the CRRES program

NASA Technical Reports Server (NTRS)

Mende, Stephen B.

1994-01-01

This report submitted is the final report and covers work performed under the contract for the period Apr. 12, 1985 - Dec. 23, 1993. The CRRES program investigated earth plasma environment by active experiments in which metal vapors were injected into the upper atmosphere and magnetosphere. The vapor clouds perturb the ambient ionospheric / magnetospheric environment and the effects could be monitored by passive observing instruments. Our part of the CRRES program, the Artificial Plasma Experiment program, was a ground based and aircraft based investigation to observe artificial chemical releases by optical techniques.

Simulation of acid mine drainage generation around Küre VMS Deposits, Northern Turkey

NASA Astrophysics Data System (ADS)

Demirel, Cansu; Kurt, Mehmet Ali; Çelik Balci, Nurgül

2015-04-01

This study investigated comparative leaching characteristics of acidophilic bacterial strains under shifting environmental conditions at proposed two stages as formation stage or post acidic mine drainage (AMD) generation. At the first stage, initial reactions associated with AMD generation was simulated in shaking flasks containing massive pyritic chalcopyrite ore by using a pure strain Acidithiobacillus ferrooxidans and a mixed culture of Acidithiobacillus sp. mostly dominated by A. ferrooxidans and A. thiooxidans at 26oC. At the second stage, long term bioleaching experiments were carried out with the same strains at 26oC and 40oC to investigate the leaching characteristics of pyritic chalcopyrite ore under elevated heavy metal and temperature conditions. During the experiments, physicochemical characteristics (e.i. Eh, pH, EC) metal (Fe, Co, Cu, Zn) and sulfate concentration of the experimental solution were monitored during 180 days. Significant acid generation and sulfate release were determined during bioleaching of the ore by mixed acidophilic cultures containing both iron and sulfur oxidizers. In the early stage of the experiments, heavy metal release from the ore was caused by generation of acid due to accelerated bacterial oxidation of the ore. Generally high concentrations of Co and Cu were released into the solution from the experiments conducted by pure cultures of Acidithiobacillus ferrooxidans whereas high Zn and Fe was released into the solution from the mixed culture experiments. In the later stage of AMD generation and post AMD, chemical oxidation is accelerated causing excessive amounts of contamination, even exceeding the amounts resulted from bacterial oxidation by mixed cultures. Acidithibacillus ferrooxidans was found to be more effective in leaching Cu, Fe and Co at higher temperatures in contrary to mixed acidophiles that are more prone to operate at optimal moderate conditions. Moreover, decreasing Fe values are noted in bioleaching experiments with mixed acidophiles at higher temperatures. Further depleted Fe(III) values coinciding with decreasing pH may point to precipitation of secondary phases (i.e. jarosite). This study revealed that the metals (Fe, Cu, Co and Zn) released during short term leaching of the ore (34 days) are generally caused by acid produced by dissolution reactions rather than oxidation. In the long term experiments a more complex biogeochemical reactions (oxidation and dissolution) take place in conjunction. Key words: Bioleaching, AMD, heavy metal release, environment, acidophilic bacteria, Küre copper ore deposits, volcanogenic massive sulfide deposits

Sustained-release theophylline and nocturnal asthma, once-daily and unequal dosing schedules.

PubMed

Smolensky, M H; D'Alonzo, G E; Kunkel, G; Barnes, P J

1987-01-01

Many asthmatic patients experience aggravation of symptoms overnight resulting in disruption of their sleep. Sustained-release theophylline represents at this time a major bronchodilator medication which possesses a sufficient duration of activity to avert the nocturnal breathing distress of asthma. Circadian rhythm-adapted theophylline schedules consisting of unequal dosing--more or all the drug taken in the evening--have proven efficacious in clinical investigations for certain patients. Although the kinetic behavior of some formulations is affected by food, the circadian rhythm-adapted schedules represent a significant step forward toward the goal of optimizating sustained-release theophyllines for patients who experience nighttime symptoms.

An oxygen slow-releasing material and its application in water remediation as oxygen supplier.

PubMed

Zhou, Yanbo; Fang, Xingbin; Zhang, Zhiqing; Hu, Yonghua; Lu, Jun

2017-11-01

In this study, an oxygen slow-releasing material (OSRM) consisting of calcium peroxide (CaO 2 ), stearic acid (SA) and quartz sand was used to improve oxygen supply during bioremediation. The oxygen-releasing rates of CaO 2 powder and OSRM with different SA contents were investigated. The efficacy of OSRM as an oxygen supplier was assessed by water remediation experiments using activated sludge. Results showed that CaO 2 powder was effectively embedded by SA under anhydrous conditions. The oxygen-releasing rate decreased with increasing SA contents. Moreover, the OSRM exhibited higher oxygen-releasing capacity, and more effective pH control ability than CaO 2 powder. The water remediation experiments showed better removal of COD and [Formula: see text] with OSRM as the oxygen supplier. These results provided detailed information when CaO 2 was applied as the oxygen supplier in water remediation, which can serve as references for field application of bioremediation.

Influence of prerelease experience on reintroduced black-footed ferrets (Mustela nigripes)

USGS Publications Warehouse

Biggins, D.E.; Vargas, A.; Godbey, J.L.; Anderson, S.H.

1999-01-01

Captive breeding is increasingly being used to create supplies of endangered animals for release into natural habitats, but rearing strategies vary and debates arise over which methods are most efficient. We assessed postrelease behaviors and survival of three groups of black-footed ferrets, each with different prerelease experience. Eighteen ferret kits ???60 days of age were moved with their dams from cages to 80-m2 outdoor pens with prairie dog burrows. These animals were compared to animals reared in standard cages (n = 72), some of which were given experience killing prairie dogs (n = 32). Ferrets were released onto white-tailed prairie dog (Cynomys leucurus) colonies in Wyoming, USA, in fall, 1992. Radio-tagged cage-reared ferrets made longer nightly moves and dispersed further from release sites than their pen-reared counterparts. The band return rate was 4-fold higher for pen-reared animals than for cage-reared animals during surveys conducted about 1 month after release. We recommend routine use of quasi-natural outdoor pens for prerelease conditioning of black-footed ferrets.

In vitro determination of HT oxidation activity and tritium concentration in soil and vegetation during the chronic HT release experiment at Chalk River

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

Ichimasa, Y.; Ichimasa, M.; Jiang, H.

1995-10-01

The oxidation activity of molecular tritium (HT) in soils and vegetation collected in experimental plots during the 1994 chronic HT release experiment at Chalk River was determined in vitro laboratory experiments after the release. HT oxidation activity was highest in surface soils in the natural plot, about 3-4 times that in soils in the cultivated plots. HT oxidation activity in weeds and Komatsuna leaves was about 2 and 0.4% of that in the cultivated soil, respectively. The number of HT-oxidizing bacteria isolated from soils was highest in the surface soil (0-5 cm) in the natural plot. The viable cell numbersmore » in surface soils in the cultivated and natural plots were almost the same. The total occurrence rates of HT-oxidizing bacteria in the surface soils were 22% in the natural plot, and 7.5% in the cultivated plot. The occurrence rates of HT-oxidizing airborne bacteria during the release on two culture media were 4.2 and 1.9%. 16 refs., 3 figs., 3 tabs.« less

Chronic nicotine administration differentially affects neurotransmitter release from rat striatal slices.

PubMed

Yu, Z J; Wecker, L

1994-07-01

The objective of these experiments was to determine whether the chronic administration of nicotine, at a dose regimen that increases the density of nicotine binding sites, alters the nicotine-induced release of [3H]-dopamine ([3H]DA), [3H]norepinephrine ([3H]NE), [3H]-serotonin ([3H]5-HT), or [3H]acetylcholine ([3H]ACh) from rat striatal slices. For these experiments, rats received subcutaneous injections of either saline or nicotine bitartrate [1.76 mg (3.6 mumol)/kg, dissolved in saline] twice daily for 10 days, and neurotransmitter release was measured following preloading of the tissues with [3H]DA, [3H]NE, [3H]5-HT, or [3H]choline. Chronic nicotine administration did not affect the accumulation of tritium by striatal slices, the basal release of radioactivity, or the 25 mM KCl-evoked release of neurotransmitter. Superfusion of striatal slices with 1, 10, and 100 microM nicotine increased [3H]DA release in a concentration-dependent manner, and release from slices from nicotine-injected animals was significantly (p < 0.05) greater than release from saline-injected controls; release from the former increased to 132, 191, and 172% of release from the controls following superfusion with 1, 10, and 100 microM nicotine, respectively. Similarly, [3H]5-HT release increased in a concentration-related manner following superfusion with nicotine, and release from slices from nicotine-injected rats was significantly (p < 0.05) greater than that from controls. [3H]5-HT release from slices from nicotine-injected rats evoked by superfusion with 1 and 10 microM nicotine increased to 453 and 217%, respectively, of release from slices from saline-injected animals. The nicotine-induced release of [3H]NE from striatal slices was also concentration dependent but was unaffected by chronic nicotine administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Transport and Dispersion Model Predictions of Elevated Source Tracer Experiments in the Copenhagen Area: Comparisons of Hazard Prediction and Assessment Capability (HPAC) and National Atmospheric Release Advisory Center (NARAC) Emergency Response Model Predictions

DTIC Science & Technology

2006-07-01

Blue --) and NARAC (Red -) for two elevated releases ( MvM 3 and MvM 15) considered in the model-to-model study [2]. MvM 3 was a gas release (SF6...carried out under stable conditions with a boundary layer height of 100 m and release height of 80 m, while MvM 15 was a particle release carried out...release scenarios: MvM 3 at 30 and 60 Minutes and MvM 15 at 120 and 180 minutes. Each release shows significant NARAC underpredictions with

The Visible Human Data Sets (VHD) and Insight Toolkit (ITk): Experiments in Open Source Software

PubMed Central

Ackerman, Michael J.; Yoo, Terry S.

2003-01-01

From its inception in 1989, the Visible Human Project was designed as an experiment in open source software. In 1994 and 1995 the male and female Visible Human data sets were released by the National Library of Medicine (NLM) as open source data sets. In 2002 the NLM released the first version of the Insight Toolkit (ITk) as open source software. PMID:14728278

Converting Existing Copper Wire Firing System to a Fiber Optically Controlled Firing System for Electromagnetic Pulsed Power Experiments

DTIC Science & Technology

2017-12-19

Firing System for Electromagnetic Pulsed Power Experiments by Robert Borys Jr and Colby Adams Approved for public release...Belcamp, MD Approved for public release; distribution is unlimited. ii REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188... Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions

Improving ammonium and nitrate release from urea using clinoptilolite zeolite and compost produced from agricultural wastes.

PubMed

Omar, Latifah; Ahmed, Osumanu Haruna; Ab Majid, Nik Muhamad

2015-01-01

Improper use of urea may cause environmental pollution through NH3 volatilization and NO3 (-) leaching from urea. Clinoptilolite zeolite and compost could be used to control N loss from urea by controlling NH4 (+) and NO3 (-) release from urea. Soil incubation and leaching experiments were conducted to determine the effects of clinoptilolite zeolite and compost on controlling NH4 (+) and NO3 (-) losses from urea. Bekenu Series soil (Typic Paleudults) was incubated for 30, 60, and 90 days. A soil leaching experiment was conducted for 30 days. Urea amended with clinoptilolite zeolite and compost significantly reduced NH4 (+) and NO3 (-) release from urea (soil incubation study) compared with urea alone, thus reducing leaching of these ions. Ammonium and NO3 (-) leaching losses during the 30 days of the leaching experiment were highest in urea alone compared with urea with clinoptilolite zeolite and compost treatments. At 30 days of the leaching experiment, NH4 (+) retention in soil with urea amended with clinoptilolite zeolite and compost was better than that with urea alone. These observations were because of the high pH, CEC, and other chemical properties of clinoptilolite zeolite and compost. Urea can be amended with clinoptilolite zeolite and compost to improve NH4 (+) and NO3 (-) release from urea.

Uranium Release from Acidic Weathered Hanford Sediments: Single-Pass Flow-Through and Column Experiments

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

Wang, Guohui; Um, Wooyong; Wang, Zheming

The reaction of acidic radioactive waste with sediments can induce mineral transformation reactions that, in turn, control contaminant fate. Here, sediment weathering by synthetic uranium-containing acid solutions was investigated using bench-scale experiments to simulate waste disposal conditions at Hanford’s cribs, USA. During acid weathering, the presence of phosphate exerted a strong influence over uranium mineralogy and a rapidly precipitated, crystalline uranium phosphate phase (meta-ankoleite [K(UO2)(PO4)·3H2O]) was identified using spectroscopic and diffraction-based techniques. In phosphate-free system, uranium oxyhydroxide minerals such as K-compreignacite [K2(UO2)6O4(OH)6·7H2O] were formed. Single-pass flow-through (SPFT) and column leaching experiments using synthetic Hanford pore water showed that uranium precipitatedmore » as meta-ankoleite during acid weathering was strongly retained in the sediments, with an average release rate of 2.67E-12 mol g-1 s-1. In the absence of phosphate, uranium release was controlled by dissolution of uranium oxyhydroxide (compreignacite-type) mineral with a release rate of 1.05-2.42E-10 mol g-1 s-1. The uranium mineralogy and release rates determined for both systems in this study support the development of accurate U-release models for prediction of contaminant transport. These results suggest that phosphate minerals may be a good candidate for uranium remediation approaches at contaminated sites.« less

Uranium Release from Acidic Weathered Hanford Sediments: Single-Pass Flow-Through and Column Experiments.

PubMed

Wang, Guohui; Um, Wooyong; Wang, Zheming; Reinoso-Maset, Estela; Washton, Nancy M; Mueller, Karl T; Perdrial, Nicolas; O'Day, Peggy A; Chorover, Jon

2017-10-03

The reaction of acidic radioactive waste with sediments can induce mineral transformation reactions that, in turn, control contaminant fate. Here, sediment weathering by synthetic uranium-containing acid solutions was investigated using bench-scale experiments to simulate waste disposal conditions at Hanford's cribs (Hanford, WA). During acid weathering, the presence of phosphate exerted a strong influence over uranium mineralogy and a rapidly precipitated, crystalline uranium phosphate phase (meta-ankoleite [K(UO 2 )(PO 4 )·3H 2 O]) was identified using spectroscopic and diffraction-based techniques. In phosphate-free system, uranium oxyhydroxide minerals such as K-compreignacite [K 2 (UO 2 ) 6 O 4 (OH) 6 ·7H 2 O] were formed. Single-pass flow-through (SPFT) and column leaching experiments using synthetic Hanford pore water showed that uranium precipitated as meta-ankoleite during acid weathering was strongly retained in the sediments, with an average release rate of 2.67 × 10 -12 mol g -1 s -1 . In the absence of phosphate, uranium release was controlled by dissolution of uranium oxyhydroxide (compreignacite-type) mineral with a release rate of 1.05-2.42 × 10 -10 mol g -1 s -1 . The uranium mineralogy and release rates determined for both systems in this study support the development of accurate U-release models for the prediction of contaminant transport. These results suggest that phosphate minerals may be a good candidate for uranium remediation approaches at contaminated sites.

SEMICONDUCTOR TECHNOLOGY Supercritical carbon dioxide process for releasing stuck cantilever beams

NASA Astrophysics Data System (ADS)

Yu, Hui; Chaoqun, Gao; Lei, Wang; Yupeng, Jing

2010-10-01

The multi-SCCO2 (supercritical carbon dioxide) release and dry process based on our specialized SCCO2 semiconductor process equipment is investigated and the releasing mechanism is discussed. The experiment results show that stuck cantilever beams were held up again under SCCO2 high pressure treatment and the repeatability of this process is nearly 100%.

The response of abyssal organisms to low pH conditions during a series of CO2-release experiments simulating deep-sea carbon sequestration

NASA Astrophysics Data System (ADS)

Barry, J. P.; Buck, K. R.; Lovera, C.; Brewer, P. G.; Seibel, B. A.; Drazen, J. C.; Tamburri, M. N.; Whaling, P. J.; Kuhnz, L.; Pane, E. F.

2013-08-01

The effects of low-pH, high-pCO2 conditions on deep-sea organisms were examined during four deep-sea CO2 release experiments simulating deep-ocean C sequestration by the direct injection of CO2 into the deep sea. We examined the survival of common deep-sea, benthic organisms (microbes; macrofauna, dominated by Polychaeta, Nematoda, Crustacea, Mollusca; megafauna, Echinodermata, Mollusca, Pisces) exposed to low-pH waters emanating as a dissolution plume from pools of liquid carbon dioxide released on the seabed during four abyssal CO2-release experiments. Microbial abundance in deep-sea sediments was unchanged in one experiment, but increased under environmental hypercapnia during another, where the microbial assemblage may have benefited indirectly from the negative impact of low-pH conditions on other taxa. Lower abyssal metazoans exhibited low survival rates near CO2 pools. No urchins or holothurians survived during 30-42 days of exposure to episodic, but severe environmental hypercapnia during one experiment (E1; pH reduced by as much as ca. 1.4 units). These large pH reductions also caused 75% mortality for the deep-sea amphipod, Haploops lodo, near CO2 pools. Survival under smaller pH reductions (ΔpH<0.4 units) in other experiments (E2, E3, E5) was higher for all taxa, including echinoderms. Gastropods, cephalopods, and fish were more tolerant than most other taxa. The gastropod Retimohnia sp. and octopus Benthoctopus sp. survived exposure to pH reductions that episodically reached -0.3 pH units. Ninety percent of abyssal zoarcids (Pachycara bulbiceps) survived exposure to pH changes reaching ca. -0.3 pH units during 30-42 day-long experiments.

Environmental analysis of the chemical release module. [space shuttle payload

NASA Technical Reports Server (NTRS)

Heppner, J. P.; Dubin, M.

1980-01-01

The environmental analysis of the Chemical Release Module (a free flying spacecraft deployed from the space shuttle to perform chemical release experiments) is reviewed. Considerations of possible effects of the injectants on human health, ionosphere, weather, ground based optical astronomical observations, and satellite operations are included. It is concluded that no deleterious environmental effects of widespread or long lasting nature are anticipated from chemical releases in the upper atmosphere of the type indicated for the program.

A nanohybrid system for taste masking of sildenafil.

PubMed

Lee, Ji-Hee; Choi, Goeun; Oh, Yeon-Ji; Park, Je Won; Choy, Young Bin; Park, Mung Chul; Yoon, Yeo Joon; Lee, Hwa Jeong; Chang, Hee Chul; Choy, Jin-Ho

2012-01-01

A nanohybrid was prepared with an inorganic clay material, montmorillonite (MMT), for taste masking of sildenafil (SDN). To further improve the taste-masking efficiency and enhance the drug-release rate, we coated the nanohybrid of SDN-MMT with a basic polymer, polyvinylacetal diethylaminoacetate (AEA). Powder X-ray diffraction and Fourier transform infrared experiments showed that SDN was successfully intercalated into the interlayer space of MMT. The AEA-coated SDN-MMT nanohybrid showed drug release was much suppressed at neutral pH (release rate, 4.70 ± 0.53%), suggesting a potential for drug taste masking at the buccal cavity. We also performed in vitro drug release experiments in a simulated gastric fluid (pH = 1.2) and compared the drug-release profiles of AEA-coated SDN-MMT and Viagra(®), an approved dosage form of SDN. As a result, about 90% of SDN was released from the AEA-coated SDN-MMT during the first 2 hours while almost 100% of drug was released from Viagra(®). However, an in vivo experiment showed that the AEA-coated SDN-MMT exhibited higher drug exposure than Viagra(®). For the AEA-coated SDN-MMT, the area under the plasma concentration- time curve from 0 hours to infinity (AUC(0-∞)) and maximum concentration (C(max)) were 78.8 ± 2.32 μg · hour/mL and 12.4 ± 0.673 μg/mL, respectively, both of which were larger than those obtained with Viagra(®) (AUC(0-∞) = 69.2 ± 3.19 μg · hour/mL; C(max) = 10.5 ± 0.641 μg/mL). Therefore, we concluded that the MMT-based nanohybrid is a promising delivery system for taste masking of SDN with possibly improved drug exposure.

A nanohybrid system for taste masking of sildenafil

PubMed Central

Lee, Ji-Hee; Choi, Goeun; Oh, Yeon-Ji; Park, Je Won; Choy, Young Bin; Park, Mung Chul; Yoon, Yeo Joon; Lee, Hwa Jeong; Chang, Hee Chul; Choy, Jin-Ho

2012-01-01

A nanohybrid was prepared with an inorganic clay material, montmorillonite (MMT), for taste masking of sildenafil (SDN). To further improve the taste-masking efficiency and enhance the drug-release rate, we coated the nanohybrid of SDN–MMT with a basic polymer, polyvinylacetal diethylaminoacetate (AEA). Powder X-ray diffraction and Fourier transform infrared experiments showed that SDN was successfully intercalated into the interlayer space of MMT. The AEA-coated SDN–MMT nanohybrid showed drug release was much suppressed at neutral pH (release rate, 4.70 ± 0.53%), suggesting a potential for drug taste masking at the buccal cavity. We also performed in vitro drug release experiments in a simulated gastric fluid (pH = 1.2) and compared the drug-release profiles of AEA-coated SDN–MMT and Viagra®, an approved dosage form of SDN. As a result, about 90% of SDN was released from the AEA-coated SDN–MMT during the first 2 hours while almost 100% of drug was released from Viagra®. However, an in vivo experiment showed that the AEA-coated SDN–MMT exhibited higher drug exposure than Viagra®. For the AEA-coated SDN–MMT, the area under the plasma concentration– time curve from 0 hours to infinity (AUC0-∞) and maximum concentration (Cmax) were 78.8 ± 2.32 μg · hour/mL and 12.4 ± 0.673 μg/mL, respectively, both of which were larger than those obtained with Viagra® (AUC0-∞ = 69.2 ± 3.19 μg · hour/mL; Cmax = 10.5 ± 0.641 μg/mL). Therefore, we concluded that the MMT-based nanohybrid is a promising delivery system for taste masking of SDN with possibly improved drug exposure. PMID:22619517

Acetylcholine release from the rabbit isolated superior cervical ganglion preparation.

PubMed

Dawes, P M; Vizi, E S

1973-06-01

1. The rabbit isolated superior cervical ganglion preparation has been used to measure the release of acetylcholine from the tissue at rest and during preganglionic nerve stimulation.2. In the presence of physostigmine, the resting release of acetylcholine was 0.13 +/- 0.01 (nmol/g)/min (10 experiments) and that during stimulation with 300 shocks at 10 Hz was 3.1 +/- 0.4 (pmol/g)/volley in 4 experiments (means +/- S.E.M.). The volley output was independent of the frequency of stimulation over the range 1 to 10 Hz but was higher at 0.3 Hz.3. Tetrodotoxin, 0.8 muM, had no effect on the resting release of acetylcholine but reduced the stimulated release below detectable levels (2 pmol). Lowering the temperature of the bathing fluid to 5 degrees C reduced to below detectable levels both the resting release and that produced by nerve stimulation.4. The resting release of acetylcholine was increased by a potassium-rich (49.4 mM K(+)) bathing solution and by replacing the sodium chloride in the solution with lithium chloride (113 mM Li(+)).5. (-)-Noradrenaline bitartrate, 3 muM, and (+/-)-adrenaline bitartrate, 1.5 muM, reduced by 70% the output of acetylcholine induced by stimulation at 0.3 Hz, but failed to reduce the resting release or that evoked by stimulation at 10 Hz. The inhibition was reversed by phentolamine.6. It is concluded that the rabbit superior cervical ganglion in vitro is a suitable preparation for studying transmitter release and that the ganglion blocking effect of catecholamines is due to a reduction in transmitter release.

Development of orally disintegrating tablets comprising controlled-release multiparticulate beads

PubMed Central

2012-01-01

Melperone is an atypical antipsychotic agent that has shown a wide spectrum of neuroleptic properties, particularly effective in the treatment of senile dementia and Parkinson’s-associated psychosis, and is marketed in Europe as an immediate-release (IR) tablet and syrup. An orally disintegrating tablet (ODT) dosage form would be advantageous for patients who experience difficulty in swallowing large tablets or capsules or those who experience dysphagia. Controlled-release (CR) capsule and ODT formulations containing melperone HCl were developed with target in vitro release profiles suitable for a once-daily dosing regimen. Both dosage forms allow for the convenient production of dose-proportional multiple strengths. Two ODT formulations exhibiting fast and medium release profiles and one medium release profile capsule formulation (each 50 mg) were tested in vivo using IR syrup as the reference. The two medium release formulations were shown to be bioequivalent to each other and are suitable for once-daily dosing. Based on the analytical and organoleptic test results, as well as the blend uniformity and in-process compression data at various compression forces using coated beads produced at one-tenth (1/10) commercial scale, both formulations in the form of CR capsules and CR ODTs have shown suitability for progression into further clinical development. PMID:22356215

Prediction of dexamethasone release from PLGA microspheres prepared with polymer blends using a design of experiment approach.

PubMed

Gu, Bing; Burgess, Diane J

2015-11-10

Hydrophobic drug release from poly (lactic-co-glycolic acid) (PLGA) microspheres typically exhibits a tri-phasic profile with a burst release phase followed by a lag phase and a secondary release phase. High burst release can be associated with adverse effects and the efficacy of the formulation cannot be ensured during a long lag phase. Accordingly, the development of a long-acting microsphere product requires optimization of all drug release phases. The purpose of the current study was to investigate whether a blend of low and high molecular weight polymers can be used to reduce the burst release and eliminate/minimize the lag phase. A single emulsion solvent evaporation method was used to prepare microspheres using blends of two PLGA polymers (PLGA5050 (25 kDa) and PLGA9010 (113 kDa)). A central composite design approach was applied to investigate the effect of formulation composition on dexamethasone release from these microspheres. Mathematical models obtained from this design of experiments study were utilized to generate a design space with maximized microsphere drug loading and reduced burst release. Specifically, a drug loading close to 15% can be achieved and a burst release less than 10% when a composition of 80% PLGA9010 and 90 mg of dexamethasone is used. In order to better describe the lag phase, a heat map was generated based on dexamethasone release from the PLGA microsphere/PVA hydrogel composite coatings. Using the heat map an optimized formulation with minimum lag phase was selected. The microspheres were also characterized for particle size/size distribution, thermal properties and morphology. The particle size was demonstrated to be related to the polymer concentration and the ratio of the two polymers but not to the dexamethasone concentration. Copyright © 2015 Elsevier B.V. All rights reserved.

An Analysis of the Second Project High Water Data

NASA Technical Reports Server (NTRS)

Woodbridge, David D.; Lasater, James A.; Fultz, Bennett M.; Clark, Richard E.; Wylie, Nancy

1963-01-01

Early in 1962 NASA established "Project High Water" to investigate the sudden release of large quantities of water into the upper atmosphere. The primary objectives of these experiments were to obtain information on the behavior of liquids released in the ionosphere and the localized effects on the ionosphere produced by the injection of large quantities of water. The data obtained in the two (2) Project High Water experiments have yielded an extensive amount of information concerning the complex phenomena associated with the sudden release of liquids in the Ionosphere. The detailed analysis of data obtained during the second Project High Water experiment (i.e., the third Saturn I vehicle test or SA-3) presented in this report demonstrates that the objectives of the Project High Water were achieved. In addition, the Project High Water has provided essential information relevant to a number of problems vital to manned explorations of space.

Active experiments in space plasmas; Symposium D4.1 of Commission D, COSPAR Scientific Assembly, 30th, Hamburg, Germany, July 11-21, 1994

NASA Technical Reports Server (NTRS)

Rietveld, M. T. (Editor)

1995-01-01

Papers from the conference are presented and cover the following topics: ion and electron beams; ionospheric modification; spacecraft interactions; chemical releases; and plasma waves. Auroras and plasma emissions are reported from electron beam injection experiments on the EXCEDE 3 rocket and APEX satellite respectively. The important parameters affecting the charging of spacecraft during the operation of electron guns is covered. The Active Magnetospheric Particle Acceleration Satellite (AMPAS) mission utilizing dual-payload tethered satellites and both up and downward directed electron beams is proposed to study the magnetosphere. Recent results and associated theories from the Sura, Arecibo and Troms ionospheric heating facitlites are presented. The effects of neutral gases on spacecraft charging are examined in a series of rocket flights. Many results from the Combined Release and Radiation Effects Satellite chemical release experiments are presented.

The use of sequential mark-release-recapture experiments to estimate population size, survival and dispersal of male mosquitoes of the  Anopheles gambiae complex in Bana, a west African humid savannah village.

PubMed

Epopa, Patric Stephane; Millogo, Abdoul Azize; Collins, Catherine Matilda; North, Ace; Tripet, Frederic; Benedict, Mark Quentin; Diabate, Abdoulaye

2017-08-07

Vector control is a major component of the malaria control strategy. The increasing spread of insecticide resistance has encouraged the development of new tools such as genetic control which use releases of modified male mosquitoes. The use of male mosquitoes as part of a control strategy requires an improved understanding of male mosquito biology, including the factors influencing their survival and dispersal, as well as the ability to accurately estimate the size of a target mosquito population. This study was designed to determine the seasonal variation in population size via repeated mark-release-recapture experiments and to estimate the survival and dispersal of male mosquitoes of the Anopheles gambiae complex in a small west African village. Mark-release-recapture experiments were carried out in Bana Village over two consecutive years, during the wet and the dry seasons. For each experiment, around 5000 (3407-5273) adult male Anopheles coluzzii mosquitoes were marked using three different colour dye powders (red, blue and green) and released in three different locations in the village (centre, edge and outside). Mosquitoes were recaptured at sites spread over the village for seven consecutive days following the releases. Three different capture methods were used: clay pots, pyrethroid spray catches and swarm sampling. Swarm sampling was the most productive method for recapturing male mosquitoes in the field. Population size and survival were estimated by Bayesian analyses of the Fisher-Ford model, revealing an about 10-fold increase in population size estimates between the end of dry season (10,000-50,000) to the wet season (100,000-500,000). There were no detectable seasonal effects on mosquito survival, suggesting that factors other than weather may play an important role. Mosquito dispersal ranged from 40 to 549 m over the seven days of each study and was not influenced by the season, but mainly by the release location, which explained more than 44% of the variance in net dispersal distance. This study clearly shows that male-based MRR experiments can be used to estimate some parameters of wild male populations such as population size, survival, and dispersal and to estimate the spatial patterns of movement in a given locality.

Slow Release Of Reagent Chemicals From Gel Matrices

NASA Technical Reports Server (NTRS)

Debnam, William J.; Barber, Patrick G.; Coleman, James

1988-01-01

Procedure developed for slow release of reagent chemicals into solutions. Simple and inexpensive and not subject to failure of equipment. Use of toothpaste-type tube or pump dispenser conceivably provides more controlled technique for storage and dispensation of gel matrix. Possible uses include controlled, slow release of reagents in chemical reactions, crystal growth, space-flight experiments, and preformed gel medications from packets.

Fluoride release, recharge, and re-release from four orthodontic bonding systems

NASA Astrophysics Data System (ADS)

Bouvier, Amy Johanna

Objectives: To determine the amount of initial fluoride release from four orthodontic bonding systems over a period of four weeks, and then to subject these materials to an external source of fluoride for recharge in order to measure the amount of fluoride re-release over another four-week interval. Additionally the surface morphology of these materials was analyzed under the scanning electron microscope in order to identify microscopic changes in the materials that may have occurred during the experiment. Methods: Four orthodontic adhesives: Fuji Ortho LC (GC America, Alsip, IL), Transbond XT (3M Unitek, Monrovia, CA), Illuminate Light Cure (Ortho Organizers, Carlsbad, CA), and Opal Seal with Opal Bond MV (Ultradent, South Jordan, UT), n=120 (30/material) were tested for fluoride release at 1 hour, 24 hours, 3 days, 1 week, 2 weeks, 3 weeks and 4 weeks. Samples (10/subgroup/material) were then recharged with an external source of fluoride (toothpaste, foam, or varnish), and retested for fluoride re-release at 1 hour, 24 hours, 3 days, 1 week, 2 weeks, 3 weeks and 4 weeks. The scanning electron microscope was utilized in order to assess each material's surface morphology before testing and after completion of the experiment (n=16). Descriptive statistics, means and standard deviations were calculated for all four materials and their subgroups at each time interval. A mixed model two-way ANOVA was run, using a level of significance of 0.05. Bonferroni multiple comparison tests were conducted using if groups were found to be statistically significantly different. To determine significant differences between fluoride release and re-release for each recharge subgroup within each material group, paired t-tests were performed for the time intervals of 24 hours, 2 weeks, and 4 weeks. For the paired t-tests, the level of significance used was 0.02 to allow for Bonferroni correction. Results: During the initial 24 hours the fluoride measurements (in mg/L or ppm) were as follows: Fuji 9.78+/-0.65, Illuminate 7.83+/-1.49, Opal 0.05+/-0.02, and Transbond 0.01+/-0.0. At the initial four weeks time point, the readings were as follows: Fuji 6.68+/-0.79, Illuminate 3.82+/-1.84, Opal 0.06+/-0.01, and Transbond 0.01+/-0.01. The greatest fluoride release came from the varnish subgroups from each of the materials at 2 weeks post re-charge: Fuji 9.16+/-1.53, Illuminate 7.5+/-3.1 (tied with foam subgroup 7.5+/-4.4), Opal 5.3+/-2.45, and Transbond 3.75+/-1.67. The greatest fluoride measurement for each material at the final week post-recharge was: Fuji varnish subgroup 8.3+/-3.58, Illuminate foam subgroup 6.5+/-3.5, Opal varnish subgroup 2.50+/-1.1, and Transbond varnish subgroup 1.72+/-1.82. SEM results showed an observable difference between the materials pre-experiment and post-experiment at a magnification of 50X and 500X. The Fuji foam and paste subgroups displayed surface crackling patterns at both magnifications when compared to the control and varnish samples. The Illuminate control, foam, and paste specimens all had a roughened grainy appearance, while the varnish specimen seemed to be smoothed over by the varnish material. The Transbond samples appeared to have observable differences in surface morphology at 50X, but not at 500X. The Opal paste and foam specimens appeared to have a smoother surface than both the control and the varnish samples. Conclusions: There were significant differences in release and re-release of fluoride among all four adhesives at different time intervals over a period of eight weeks. Significant increase in fluoride re-release was seen for all three of the recharge subgroups for both Opal and Transbond at each time interval. A significant increase in fluoride re-release for the Illuminate group was mainly observed at the end of second and fourth week. Though no significant increase in fluoride re-release was observed, Fuji released highest amount of fluoride during release and re-release, at all different time intervals. Fluoride varnish was the superior recharge material, as it provided the greatest fluoride measurements, followed by foam and toothpaste. There were observable changes in the surface morphology of the materials pre-experiment and post-experiment at a magnification of 50X and 500X, which may have an affect on the fluoride releasing capabilities of the materials.

The influence of the tropics upon the prediction of the Southern Hemisphere circulation within the GLAS GCM. [Goddard Laboratory for Atmospheric Sciences General Circulation Model

NASA Technical Reports Server (NTRS)

Baker, W. E.; Paegle, J.

1983-01-01

An examination is undertaken of the sensitivity of short term Southern Hemisphere circulation prediction to tropical wind data and tropical latent heat release. The data assimilation experiments employ the Goddard Laboratory for Atmospheric Sciences' fourth-order general circulation model. Two of the experiments are identical, but for the fact that one uses tropical wind data while the other does not. A third experiment contains the identical initial conditions of forecasts with tropical winds, while suppressing tropical latent heat release.

OV-104's RMS releases Gamma Ray Observatory (GRO) during STS-37 deployment

NASA Image and Video Library

1991-04-07

Atlantis', Orbiter Vehicle (OV) 104's, remote manipulator system (RMS) releases Gamma Ray Observatory (GRO) during STS-37 deployment. Visible on the GRO as it drifts away from the RMS end effector are the four complement instruments: the Energetic Gamma Ray Experiment (bottom); Imaging Compton Telescope (COMPTEL) (center); Oriented Scintillation Spectrometer Experiment (OSSE) (top); and Burst and Transient Source Experiment (BATSE) (at four corners). GRO's solar array (SA) panels are extended and are in orbit configuration. View was taken through aft flight deck window which reflects some of the crew compartment interior.

Viking labeled release biology experiment - Interim results

NASA Technical Reports Server (NTRS)

Levin, G. V.; Straat, P. A.

1976-01-01

All results of the labeled-release life-detection experiment conducted on Mars prior to conjunction are summarized. Tests at both landing sites provide remarkably similar evolution of radioactive gas upon addition of a radioactive nutrient to the Mars sample. The 'active' agent in the sample is stable to 18 C, but is substantially inactivated by heat treatment for 3 hours at 50 C and completely inactivated at 160 C, as would be anticipated if the active response were caused by microorganisms. Results from test and heat-sterilized control samples are compared with those obtained from terrestrial soils and a lunar sample. Possible nonbiological explanations of the Mars data are reviewed. Although such explanations of the labeled-release data depend on UV irradiation, the labeled-release response does not appear to depend on recent direct UV activation of surface material. Available facts do not yet permit a conclusion regarding the existence of life on Mars.

SIRANERISK: Modelling dispersion of steady and unsteady pollutant releases in the urban canopy

NASA Astrophysics Data System (ADS)

Soulhac, L.; Lamaison, G.; Cierco, F.-X.; Ben Salem, N.; Salizzoni, P.; Mejean, P.; Armand, P.; Patryl, L.

2016-09-01

SIRANERISK is an operational model for the simulation of the dispersion of unsteady atmospheric releases of pollutant within and above an urban area. SIRANERISK is built on the same principles as the SIRANE model, and couples a street network model for the pollutant transfers within the urban canopy with a Gaussian puff model for the transfers above it. The performance of the model are here analysed by a detailed comparisons with wind-tunnel experiments. These experiments concern the dispersion of steady and unsteady pollutant releases within and above obstacle arrays with varying geometrical configurations, representing different topologies of idealised urban districts. The overall good agreement between numerical and experimental data demonstrates the reliability of SIRANERISK as an operational tool for the assessment of risk analysis and for the management of crises due to the accidental release of harmful airborne pollutants within a built environment.

A large-scale field trial experiment to derive effective release of heavy metals from incineration bottom ashes during construction in land reclamation.

PubMed

Chan, Wei-Ping; Ren, Fei; Dou, Xiaomin; Yin, Ke; Chang, Victor Wei-Chung

2018-05-08

Recycling of incineration bottom ashes (IBA) is attracting great interest as it is considered as a vital aspect for closing the waste loop to achieve sustainable development at the growing cities around the world. Various laboratory-testing methods are developed to assess the release potential of heavy metals - one of the most important concerns of using IBA, by reflecting the release conditions of heavy metals from IBA based on the targeted land reclamation application scenarios and corresponding environmental conditions. However, realistic release of the concerned elements in actual application with the presence of complex environment could possibly deviate from the outcomes produced by leaching tests carried out in the laboratory. Hence, a set of large-scale column trial experiments was performed to experimentally determine the effective release of heavy metals, when IBA is used as a filling material in land reclamation. 20 tons of IBA and 320 m 3 of seawater were used in six column trial experiments. The release of 13 heavy metal elements was analyzed through multiple aspects which included kinetics of release, distribution of elements in seawater and the impacts of two different dumping methods, with and without application of a chute. After dumping of IBA into the seawater, almost instantaneous release of heavy metals with uniform horizontal dispersion was observed. Higher concentration of these elements was observed near the bottom of the column, especially when a chute was applied. Comparative analysis was then carried out to establish relationships between the results obtained from the column trial with batch leaching test carried out in the laboratory. Distinctive relationships were observed for different heavy metals which suggests the need of pursuance of further understanding on leaching of IBA in real application scenario and complex environment. Copyright © 2018 Elsevier B.V. All rights reserved.

Chemical factors influencing colloid-facilitated transport of contaminants in porous media

USGS Publications Warehouse

Roy, Sujoy B.; Dzombak, David A.

1997-01-01

The effects of colloids on the transport of two strongly sorbing solutesa hydrophobic organic compound, phenanthrene, and a metal ion, Ni2+were studied in sand-packed laboratory columns under different pH and ionic strength conditions. Two types of column experiments were performed as follows:  (i) sorption/mobilization experiments where the contaminant was first sorbed in the column under conditions where no colloids were released and mobilized under conditions where colloids were released as a result of ionic strength reduction in the influent; and (ii) transport experiments where the contaminant, dissolved or sorbed on colloids, was injected into columns packed with a strongly sorbing porous medium. In the first type of experiment, contaminant mobilization was significant only when all releasable colloids were flushed from the column. In all other cases, although high colloid particle concentrations were encountered, there was no marked effect on total contaminant concentrations. In the second type of experiment, colloid deposition efficiencies were shown to control the enhancement of transport. The deposition efficiency was a function of the pH (for a high organic content sand) and of the contaminant concentration (for a charged species such as Ni2+).

A search for a nonbiological explanation of the Viking Labeled Release life detection experiment

NASA Technical Reports Server (NTRS)

Levin, G. V.; Straat, P. A.

1981-01-01

The possibility of nonbiological reactions involving hydrogen peroxide being the source of the positive response detected by the Viking Labeled Release (LR) life detection experiment on the surface of Mars is assessed. Labeled release experiments were conducted in the LR Test Standards Module which replicates the Viking flight instrument configuration on analog Martian soils prepared to match the Viking inorganic analysis of Mars surface material to which an aqueous solution of hydrogen peroxide had been added. Getter experiments were also conducted to compare several reactions simultaneously in the presence and absence of UV radiation prior to the addition of nutrient. Hydrogen peroxide on certain analog soils is found to be capable of reproducing the kinetics and thermal information contained in the Mars data. The peroxide concentration necessary for this response, however, is shown to require a chemical stability or production rate much greater than seems likely in the Mars environment. As previous experiments have shown hydrogen peroxide to be the most likely nonbiological source of the positive LR response, it is concluded that the presence of a biological agent on Mars must not yet be ruled out.

Varying iron release from transferrin and lactoferrin proteins. A laboratory experiment.

PubMed

Carmona, Fernando; González, Ana; Sánchez, Manu; Gálvez, Natividad; Cuesta, Rafael; Capdevila, Mercè; Dominguez-Vera, Jose M

2017-11-01

Iron metabolism is an important subject of study for undergraduate students of chemistry and biochemistry. Relevant laboratory exercises are scarce in the literature but would be very helpful in assisting students grasp key concepts. The experiment described here deals with different iron release mechanisms of two protagonists in iron metabolism: serum transferrin (Tf) and lactoferrin (Lf). Despite having very similar structures and iron-binding sites, Tf releases practically all its iron at pH 5.5 while Lf requires a significantly lower pH of 3. This difference in behavior is directly related to their respective biological functions as Tf blood-borne iron into the cell, while Lf competes with pathogens to sequester iron in biological fluids at more acidic pHs.  During this experiment, the students will carry out iron loading and unloading on both human Lf and Tf and monitor the iron release at different pHs using UV-Vis spectroscopy. With this simple approach, the students will discover the different patterns of iron release of Tf and Lf and how this variance in behavior relates to their biological functions. Furthermore, this laboratory practice can be expanded to allow students to investigate a variety of iron proteins. © 2017 by The International Union of Biochemistry and Molecular Biology, 45(6):521-527, 2017. © 2017 The International Union of Biochemistry and Molecular Biology.

Reported implementation lessons from a national quality improvement initiative; Productive Ward: Releasing Time to Care™. A qualitative, ward-based team perspective.

PubMed

White, Mark; Butterworth, Tony; Wells, John S G

2017-10-01

To explore the experiences of participants involved in the implementation of the Productive Ward: Releasing Time to Care™ initiative in Ireland, identifying key implementation lessons. A large-scale quality improvement programme Productive Ward: Releasing Time to Care™ was introduced nationwide into Ireland in 2011. We captured accounts from ward-based teams in an implementation phase during 2013-14 to explore their experiences. Semi-structured, in-depth interviews with a purposive sample of 24 members of ward-based teams from nine sites involved in the second national phase of the initiative were conducted. Interviews were analysed and coded under themes, using a seven-stage iterative process. The predominant theme identified was associated with the implementation and management of the initiative and included: project management; training; preparation; information and communication; and participant's negative experiences. The most prominent challenge reported related to other competing clinical priorities. Despite the structured approach of Productive Ward: Releasing Time to Care™, it appears that overstretched and busy clinical environments struggle to provide the right climate and context for ward-based teams to engage and interact actively with quality improvement tools, methods and activities. Findings highlight five key aspects of implementation and management that will help facilitate successful adoption of large-scale, ward-based quality improvement programmes such as Productive Ward: Releasing Time to Care™. Utilising pre-existing implementation or quality frameworks to assess each ward/unit for 'readiness' prior to commencing a quality improvement intervention such as Productive Ward: Releasing Time to Care™ should be considered. © 2017 John Wiley & Sons Ltd.

Dual drug release from hydrogels covalently containing polymeric micelles that possess different drug release properties.

PubMed

Murata, Mari; Uchida, Yusuke; Takami, Taku; Ito, Tomoki; Anzai, Ryosuke; Sonotaki, Seiichi; Murakami, Yoshihiko

2017-05-01

In the present study, we designed hydrogels for dual drug release: the hydrogels that covalently contained the polymeric micelles that possess different drug release properties. The hydrogels that were formed from polymeric micelles possessing a tightly packed (i.e., well-entangled) inner core exhibited a higher storage modulus than the hydrogels that were formed from the polymeric micelles possessing a loosely packed structure. Furthermore, we conducted release experiments and fluorescent observations to evaluate the profiles depicting the release of two compounds, rhodamine B and auramine O, from either polymeric micelles or hydrogels. According to our results, (1) hydrogels that covalently contains polymeric micelles that possess different drug release properties successfully exhibit the independent release behaviors of the two compounds and (2) fluorescence microscopy can greatly facilitate efforts to evaluate drug release properties of materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Shock loading and release behavior of silicon nitride

NASA Astrophysics Data System (ADS)

Kawai, N.; Tsuru, T.; Hidaka, N.; Liu, X.; Mashimo, T.

2017-01-01

Shock-reshock and shock-release experiments were performed on silicon nitride ceramics above and below its phase transition pressure. Experimental results clearly show the occurrence of elastic-plastic transition and phase transition during initial shock loading. The HEL and phase transition stress are determined as 11.6 and 34.5 GPa, respectively. Below the phase transition stress, the reshock profile consists of the single shock with short rise time, while the release profile shows the gradual release followed by rapid one. Above phase transition stress, reshock and release behavior varies with the initial shock stress. In the case of reshock and release from about 40 GPa, the reshock structure is considerably dispersed, while the release structure shows rapid release. In the reshock profile from about 50 GPa, the formation of the shock wave with the small ramped precursor is observed. And, the release response from same shocked condition shows initial gradual release and subsequent quite rapid one. These results would provide the information about how phase transformation kinetics effects on the reshock and release behavior.

ALKALINITY, PH, AND COPPER CORROSION BY-PRODUCT RELEASE

EPA Science Inventory

Contrary to expectations, higher bicarbonate concentrations exacerbate copper corrosion rates and by-product release. In fact, as illustrated by monitoring experiences of large utilities and by laboratory data, the concentration of copper corrosion by-products in drinking water i...

2-[(Hydroxymethyl)amino]ethanol in water as a preservative: Study of formaldehyde released by Taguchi's method

NASA Astrophysics Data System (ADS)

Wisessirikul, W.; Loykulnant, S.; Montha, S.; Fhulua, T.; Prapainainar, P.

2016-06-01

This research studied the quantity of free formaldehyde released from 2- [(hydroxymethyl)amino]ethanol (HAE) in DI water and natural rubber latex mixture using high-performance liquid chromatography (HPLC) technique. The quantity of formaldehyde retained in the solution was cross-checked by using titration technique. The investigated factors were the concentration of preservative (HAE), pH, and temperature. Taguchi's method was used to design the experiments. The number of experiments was reduced to 16 experiments from all possible experiments by orthogonal arrays (3 factors and 4 levels in each factor). Minitab program was used as a tool for statistical calculation and for finding the suitable condition for the preservative system. HPLC studies showed that higher temperature and higher concentration of the preservative influence the amount of formaldehyde released. It was found that conditions at which formaldehyde was released in the lowest amount were 1.6%w/v HAE, 4 to 40 °C, and the original pH. Nevertheless, the pH value of NR latex should be more than 10 (the suitable pH value was found to be 13). This preservative can be used to replace current preservative systems and can maintain the quality of latex for long-term storage. Use of the proposed preservative system was also shown to have reduced impact on the toxicity of the environment.

Improving Ammonium and Nitrate Release from Urea Using Clinoptilolite Zeolite and Compost Produced from Agricultural Wastes

PubMed Central

Omar, Latifah; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab.

2015-01-01

Improper use of urea may cause environmental pollution through NH3 volatilization and NO3 − leaching from urea. Clinoptilolite zeolite and compost could be used to control N loss from urea by controlling NH4 + and NO3 − release from urea. Soil incubation and leaching experiments were conducted to determine the effects of clinoptilolite zeolite and compost on controlling NH4 + and NO3 − losses from urea. Bekenu Series soil (Typic Paleudults) was incubated for 30, 60, and 90 days. A soil leaching experiment was conducted for 30 days. Urea amended with clinoptilolite zeolite and compost significantly reduced NH4 + and NO3 − release from urea (soil incubation study) compared with urea alone, thus reducing leaching of these ions. Ammonium and NO3 − leaching losses during the 30 days of the leaching experiment were highest in urea alone compared with urea with clinoptilolite zeolite and compost treatments. At 30 days of the leaching experiment, NH4 + retention in soil with urea amended with clinoptilolite zeolite and compost was better than that with urea alone. These observations were because of the high pH, CEC, and other chemical properties of clinoptilolite zeolite and compost. Urea can be amended with clinoptilolite zeolite and compost to improve NH4 + and NO3 − release from urea. PMID:25793220

Mineral transformation controls speciation and pore-fluid transmission of contaminants in waste-weathered Hanford sediments

NASA Astrophysics Data System (ADS)

Perdrial, Nicolas; Thompson, Aaron; O'Day, Peggy A.; Steefel, Carl I.; Chorover, Jon

2014-09-01

Portions of the Hanford Site (WA, USA) vadose zone were subjected to weathering by caustic solutions during documented releases of high level radioactive waste (containing Sr, Cs and I) from leaking underground storage tanks. Previous studies have shown that waste-sediment interactions can promote variable incorporation of contaminants into neo-formed mineral products (including feldspathoids and zeolites), but processes regulating the subsequent contaminant release from these phases into infiltrating background pore waters remain poorly known. In this paper, reactive transport experiments were conducted with Hanford sediments previously weathered for one year in simulated hyper-alkaline waste solutions containing high or low 88Sr, 127I, and 133Cs concentrations, with or without CO2(aq). These waste-weathered sediments were leached in flow-through column experiments with simulated background pore water (characteristic of meteoric recharge) to measure contaminant release from solids formed during waste-sediment interaction. Contaminant sorption-desorption kinetics and mineral transformation reactions were both monitored using continuous-flow and wet-dry cycling regimes for ca. 300 pore volumes. Less than 20% of contaminant 133Cs and 88Sr mass and less than 40% 127I mass were released over the course of the experiment. To elucidate molecular processes limiting contaminant release, reacted sediments were studied with micro- (TEM and XRD) and molecular- (Sr K-edge EXAFS) scale methods. Contaminant dynamics in column experiments were principally controlled by rapid dissolution of labile solids and competitive exchange reactions. In initially feldspathoidic systems, time-dependent changes in the local zeolitic bonding environment observed with X-ray diffraction and EXAFS are responsible for limiting contaminant release. Linear combination fits and shell-by-shell analysis of Sr K-edge EXAFS data revealed modification in Sr-Si/Al distances within the zeolite cage. Wet-dry cycling did not affect significantly molecular-scale transformations relative to continuous-flow controls. Results indicate that contaminants bound to the solid phase in distinct micro- and molecular-scale coordinative environments can generate similar macro-scale release behaviors, highlighting the need for multi-scale interrogations to constrain mechanisms of reactive transport. Data also indicate that weathering-induced change in ion exchange selectivity coefficients should be incorporated in simulations of contaminant release from caustic high-level radioactive waste impacted sediments.

[Preparation of ibuprofen/EC-PVP sustained-release composite particles by supercritical CO2 anti-solvent technology].

PubMed

Cai, Jin-Yuan; Huang, De-Chun; Wang, Zhi-Xiang; Dang, Bei-Lei; Wang, Qiu-Ling; Su, Xin-Guang

2012-06-01

Ibuprofen/ethyl-cellulose (EC)-polyvinylpyrrolidone (PVP) sustained-release composite particles were prepared by using supercritical CO2 anti-solvent technology. With drug loading as the main evaluation index, orthogonal experimental design was used to optimize the preparation process of EC-PVP/ibuprofen composite particles. The experiments such as encapsulation efficiency, particle size distribution, electron microscope analysis, infrared spectrum (IR), differential scanning calorimetry (DSC) and in vitro dissolution were used to analyze the optimal process combination. The orthogonal experimental optimization process conditions were set as follows: crystallization temperature 40 degrees C, crystallization pressure 12 MPa, PVP concentration 4 mgmL(-1), and CO2 velocity 3.5 Lmin(-1). Under the optimal conditions, the drug loading and encapsulation efficiency of ibuprofen/EC-PVP composite particles were 12.14% and 52.21%, and the average particle size of the particles was 27.621 microm. IR and DSC analysis showed that PVP might complex with EC. The experiments of in vitro dissolution showed that ibuprofen/EC-PVP composite particles had good sustained-release effect. Experiment results showed that, ibuprofen/EC-PVP sustained-release composite particles can be prepared by supercritical CO2 anti-solvent technology.

Optical observations on the CRIT-II Critical Ionization Velocity Experiment

NASA Technical Reports Server (NTRS)

Stenbaek-Nielsen, H. C.; Wescott, E. M.; Haerendel, G.; Valenzuela, A.

1990-01-01

A rocket borne Critical Ionization Velocity (CIV0 experiment was carried out from Wallops Island at dusk on May 4, 1989. Two barium shaped charges were released below the solar terminator (to prevent photoionization) at altitudes near 400 km. The ambient ionospheric electron density was 50,000/cu cm. The neutral barium jet was directed upward and at an angle of nominally 45 degrees to B which gives approximately 3 x 10 to the 23rd neutrals with super critical velocity. Ions created by a CIV process in the region of the neutral jet would travel up along B into sunlight where they can be detected optically. Well defined ion clouds (max. brightness 750 R) were observed in both releases. An ionization rate of 0.8 percent/sec (125 sec ionization time constant) can account for the observed ion cloud near the release field line, but the ionization rate falls off with increasing distance from the release. It is concluded that a CIV process was present in the neutral jet out to about 50 km from the release, which is significantly further than allowed by current theories.

Release Path Temperatures of Shock-Compressed Tin from Dynamic Reflectance and Radiance Measurements

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

La Lone, B. M.; Stevens, G. D.; Turley, W. D.

2013-08-01

Dynamic reflectance and radiance measurements were conducted for tin samples shock compressed to 35 GPa and released to 15 GPa using high explosives. We determined the reflectance of the tin samples glued to lithium fluoride windows using an integrating sphere with an internal xenon flashlamp as an illumination source. The dynamic reflectance (R) was determined at near normal incidence in four spectral bands with coverage in visible and near-infrared spectra. Uncertainties in R/R0 are < 2%, and uncertainties in absolute reflectance are < 5%. In complementary experiments, thermal radiance from the tin/glue/lithium fluoride interface was recorded with similar shock stressmore » and spectral coverage as the reflectance measurements. The two sets of experiments were combined to obtain the temperature history of the tin surface with an uncertainty of < 2%. The stress at the interface was determined from photonic Doppler velocimetry and combined with the temperatures to obtain temperature-stress release paths for tin. We discuss the relationship between the experimental release paths and release isentropes that begin on the principal shock Hugoniot.« less

Cyclodextrin-gated mesoporous silica nanoparticles as drug carriers for red light-induced drug release

NASA Astrophysics Data System (ADS)

Chai, Shiqiang; Guo, Yu; Zhang, Zhenyu; Chai, Zhen; Ma, Yurong; Qi, Limin

2017-04-01

Long wavelength light-responsive drug delivery systems based on mesoporous silica nanoparticles (MSNs) have attracted much attention in the last few years. In this paper, a red light (660 nm)-responsive drug delivery system based on low-cost cyclodextrin (CD)-gated MSNs containing a photodynamic therapy (PDT) photosensitizer (Chlorin e6, Ce6) was developed for the first time. The drug release experiment in water demonstrated that with the irradiation of red light, Ce6 can be excited to generate singlet oxygen, which can further cleave the singlet oxygen sensitive linker to trigger the departure of CD and the release of cargo. Further in vitro release experiments confirmed that cargo can be released from MSNs with the irradiation of red light and spread into the entire cell. The relative low power density (0.5 W cm-2) of excitation light together with the short irradiation time (one-three min) result in a low light dose (30-90 J cm-2) for the drug delivery, contributing to their potential clinical applications.

TMAP-7 simulation of D2 thermal release data from Be co-deposited layers

NASA Astrophysics Data System (ADS)

Baldwin, M. J.; Schwarz-Selinger, T.; Yu, J. H.; Doerner, R. P.

2013-07-01

The efficacy of (1) bake-out at 513 K and 623 K, and (2) thermal transient (10 ms) loading to up to 1000 K, is explored for reducing D inventory in 1 μm thick Be-D (D/Be ˜0.1) co-deposited layers formed at 323 K for experiment (1) and ˜500 K for experiment (2). D release data from co-deposits are obtained by thermal desorption and used to validate a model input into the Tritium Migration & Analysis Program 7 (TMAP). In (1), good agreement with experiment is found for a TMAP model encorporating traps of activation energies, 0.80 eV and 0.98 eV, whereas an additional 2 eV trap was required to model experiment (2). Thermal release is found to be trap limited, but simulations are optimal when surface recombination is taken into account. Results suggest that thick built-up co-deposited layers will hinder ITER inventory control, and that bake periods (˜1 day) will be more effective in inventory reduction than transient thermal loading.

Software Reliability Analysis of NASA Space Flight Software: A Practical Experience

PubMed Central

Sukhwani, Harish; Alonso, Javier; Trivedi, Kishor S.; Mcginnis, Issac

2017-01-01

In this paper, we present the software reliability analysis of the flight software of a recently launched space mission. For our analysis, we use the defect reports collected during the flight software development. We find that this software was developed in multiple releases, each release spanning across all software life-cycle phases. We also find that the software releases were developed and tested for four different hardware platforms, spanning from off-the-shelf or emulation hardware to actual flight hardware. For releases that exhibit reliability growth or decay, we fit Software Reliability Growth Models (SRGM); otherwise we fit a distribution function. We find that most releases exhibit reliability growth, with Log-Logistic (NHPP) and S-Shaped (NHPP) as the best-fit SRGMs. For the releases that experience reliability decay, we investigate the causes for the same. We find that such releases were the first software releases to be tested on a new hardware platform, and hence they encountered major hardware integration issues. Also such releases seem to have been developed under time pressure in order to start testing on the new hardware platform sooner. Such releases exhibit poor reliability growth, and hence exhibit high predicted failure rate. Other problems include hardware specification changes and delivery delays from vendors. Thus, our analysis provides critical insights and inputs to the management to improve the software development process. As NASA has moved towards a product line engineering for its flight software development, software for future space missions will be developed in a similar manner and hence the analysis results for this mission can be considered as a baseline for future flight software missions. PMID:29278255

Acetylcholine release from the rabbit isolated superior cervical ganglion preparation

PubMed Central

Dawes, P. M.; Vizi, E. S.

1973-01-01

1. The rabbit isolated superior cervical ganglion preparation has been used to measure the release of acetylcholine from the tissue at rest and during preganglionic nerve stimulation. 2. In the presence of physostigmine, the resting release of acetylcholine was 0·13 ± 0·01 (nmol/g)/min (10 experiments) and that during stimulation with 300 shocks at 10 Hz was 3·1 ± 0·4 (pmol/g)/volley in 4 experiments (means ± S.E.M.). The volley output was independent of the frequency of stimulation over the range 1 to 10 Hz but was higher at 0·3 Hz. 3. Tetrodotoxin, 0·8 μM, had no effect on the resting release of acetylcholine but reduced the stimulated release below detectable levels (2 pmol). Lowering the temperature of the bathing fluid to 5° C reduced to below detectable levels both the resting release and that produced by nerve stimulation. 4. The resting release of acetylcholine was increased by a potassium-rich (49·4 mM K+) bathing solution and by replacing the sodium chloride in the solution with lithium chloride (113 mM Li+). 5. (-)-Noradrenaline bitartrate, 3 μM, and (±)-adrenaline bitartrate, 1·5 μM, reduced by 70% the output of acetylcholine induced by stimulation at 0·3 Hz, but failed to reduce the resting release or that evoked by stimulation at 10 Hz. The inhibition was reversed by phentolamine. 6. It is concluded that the rabbit superior cervical ganglion in vitro is a suitable preparation for studying transmitter release and that the ganglion blocking effect of catecholamines is due to a reduction in transmitter release. PMID:4733726

Investigating the role of ion-pair strategy in regulating nicotine release from patch: Mechanistic insights based on intermolecular interaction and mobility of pressure sensitive adhesive.

PubMed

Li, Qiaoyun; Wan, Xiaocao; Liu, Chao; Fang, Liang

2018-07-01

The aim of this study was to prepare a drug-in-adhesive patch of nicotine (NIC) and use ion-pair strategy to regulate drug delivery rate. Moreover, the mechanism of how ion-pair strategy regulated drug release was elucidated at molecular level. Formulation factors including pressure sensitive adhesives (PSAs), drug loading and counter ions (C 4 , C 6 , C 8 , C 10 , and C 12 ) were screened. In vitro release experiment and in vitro transdermal experiment were conducted to determine the rate-limiting step in drug delivery process. FT-IR and molecular modeling were used to characterize the interaction between drug and PSA. Thermal analysis and rheology study were conducted to investigate the mobility variation of PSA. The optimized patch prepared with NIC-C 8 had the transdermal profile fairly close to that of the commercial product (p > 0.05). The release rate constants (k) of NIC, NIC-C 4 and NIC-C 10 were 21.1, 14.4 and 32.4, respectively. Different release rates of NIC ion-pair complexes were attributed to the dual effect of ion-pair strategy on drug release. On one hand, ion-pair strategy enhanced the interaction between drug and PSA, which inhibited drug release. On the other hand, using ion-pair strategy improved the mobility of PSA, which facilitated drug release. Drug release behavior was determined by combined effect of two aspects above. These conclusions provided a new idea for us to regulate drug release behavior from patch. Copyright © 2018 Elsevier B.V. All rights reserved.

Software Reliability Analysis of NASA Space Flight Software: A Practical Experience.

PubMed

Sukhwani, Harish; Alonso, Javier; Trivedi, Kishor S; Mcginnis, Issac

2016-01-01

In this paper, we present the software reliability analysis of the flight software of a recently launched space mission. For our analysis, we use the defect reports collected during the flight software development. We find that this software was developed in multiple releases, each release spanning across all software life-cycle phases. We also find that the software releases were developed and tested for four different hardware platforms, spanning from off-the-shelf or emulation hardware to actual flight hardware. For releases that exhibit reliability growth or decay, we fit Software Reliability Growth Models (SRGM); otherwise we fit a distribution function. We find that most releases exhibit reliability growth, with Log-Logistic (NHPP) and S-Shaped (NHPP) as the best-fit SRGMs. For the releases that experience reliability decay, we investigate the causes for the same. We find that such releases were the first software releases to be tested on a new hardware platform, and hence they encountered major hardware integration issues. Also such releases seem to have been developed under time pressure in order to start testing on the new hardware platform sooner. Such releases exhibit poor reliability growth, and hence exhibit high predicted failure rate. Other problems include hardware specification changes and delivery delays from vendors. Thus, our analysis provides critical insights and inputs to the management to improve the software development process. As NASA has moved towards a product line engineering for its flight software development, software for future space missions will be developed in a similar manner and hence the analysis results for this mission can be considered as a baseline for future flight software missions.

Pre-release host range assessment for classical biological controls: experience with predators for the hemlock woolly adelgid

Treesearch

Elizabeth Butin; Montgomery Montgomery; Nathan Havill; Joseph Elkinton

2002-01-01

There are few regulations for the release of parasitoids and predators, compared to herbivorous arthropods and pathogens, used as classical biological control agents in the United States. The types of tests conducted prior to release of the predator or parasitoid into the environment are often up to the individual wishing to introduce the new agent. Ethical researchers...

Development of a Method to Measure Organotin Release Rates

DTIC Science & Technology

1989-12-01

tributyltin per liter Pm Micrometers mm Millimeters NOSC Naval Ocean Systems Center RCW Relative confidence width TBT Tributyltin TBTCl Tributyltin ...organotin paint research is to develop a coating which controls fouling effec- tively with a minimum release of tributyltin ( TBT ). In addition to...DTNSRDC) are conducting a series of experiments in order to determine the tributyltin ( TBT ) release rates of various organotin antifouling paints. The

Development and Characterization of Chitosan Cross-Linked With Tripolyphosphate as a Sustained Release Agent in Tablets, Part I: Design of Experiments and Optimization.

PubMed

Pinto, Colin A; Saripella, Kalyan K; Loka, Nikhil C; Neau, Steven H

2018-04-01

Certain issues with the use of particles of chitosan (Ch) cross-linked with tripolyphosphate (TPP) in sustained release formulations include inefficient drug loading, burst drug release, and incomplete drug release. Acetaminophen was added to Ch:TPP particles to test for advantages of drug addition extragranularly over drug addition made during cross-linking. The influences of Ch concentration, Ch:TPP ratio, temperature, ionic strength, and pH were assessed. Design of experiments allowed identification of factors and 2-factor interactions that have significant effects on average particle size and size distribution, yield, zeta potential, and true density of the particles, as well as drug release from the directly compressed tablets. Statistical model equations directed production of a control batch that minimized span, maximized yield, and targeted a t 50 of 90 min (sample A); sample B that differed by targeting a t 50 of 240-300 min to provide sustained release; and sample C that differed from sample B by maximizing span. Sample B maximized yield and provided its targeted t 50 and the smallest average particle size, with the higher zeta potential and the lower span of samples B and C. Extragranular addition of a drug to Ch:TPP particles achieved 100% drug loading, eliminated a burst drug release, and can accomplish complete drug release. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

The analgesic agent tapentadol inhibits calcitonin gene-related peptide release from isolated rat brainstem via a serotonergic mechanism.

PubMed

Greco, Maria Cristina; Navarra, Pierluigi; Tringali, Giuseppe

2016-01-15

In this study we tested the hypothesis that tapentadol inhibits GGRP release from the rat brainstem through a mechanism mediated by the inhibition of NA reuptake; as a second alternative hypothesis, we investigated whether tapentadol inhibits GGRP release via the inhibition of 5-HT reuptake. Rat brainstems were explanted and incubated in short-term experiments. CGRP released in the incubation medium was taken as a marker of CGRP release from the central terminals of trigeminal neurons within the brainstem. CGRP levels were measured by radioimmunoassay under basal conditions or in the presence of tapentadol; NA, 5-HT, clonidine, yohimbine and ondansetron were used as pharmacological tools to investigate the action mechanism of tapentadol. The α2-antagonist yohimbine failed to counteract the effects of tapentadol. Moreover, neither NA nor the α2-agonist clonidine per se inhibited K(+)-stimulated CGRP release, thereby indicating that the effects of tapentadol are nor mediated through the block of NA reuptake. Further experiments showed that 5-HT and tramadol, which inhibits both NA and 5-HT reuptake, significantly reduced K(+)-stimulated CGRP release. Moreover, the 5-HT3 antagonist ondansetron was able to counteract the effects of tapentadol in this system. This study provided pharmacological evidence that tapentadol inhibits stimulated CGRP release from the rat brainstem in vitro through a mechanism involving an increase in 5-HT levels in the system and the subsequent activation of 5-HT3 receptors. Copyright © 2015 Elsevier Inc. All rights reserved.

Comparison of silver, cesium, and strontium release predictions using PARFUME with results from the AGR-1 irradiation experiment

DOE PAGES

Collin, Blaise P.; Petti, David A.; Demkowicz, Paul A.; ...

2015-08-22

Here, the PARFUME (PARticle FUel ModEl) code was used to predict the release of fission products silver, cesium, and strontium from tristructural isotropic coated fuel particles and compacts during the first irradiation experiment (AGR-1) of the Advanced Gas Reactor Fuel Development and Qualification program. The PARFUME model for the AGR-1 experiment used the fuel compact volume average temperature for each of the 620 days of irradiation to calculate the release of silver, cesium, and strontium from a representative particle for a select number of AGR-1 compacts. Post-irradiation examination measurements provided data on release of these fission products from fuel compactsmore » and fuel particles, and retention of silver in the compacts outside of the silicon carbide (SiC) layer. PARFUME-predicted fractional release of silver, cesium, and strontium was determined and compared to the PIE measurements. For silver, comparisons show a trend of over-prediction at low burnup and under-prediction at high burnup. PARFUME has limitations in the modeling of the temporal and spatial distributions of the temperature and burnup across the compacts, which affects the accuracy of its predictions. Nevertheless, the comparisons on silver release lie in the same order of magnitude. Results show an overall over-prediction of the fractional release of cesium by PARFUME. For particles with failed SiC layers, the over-prediction is by a factor of up to 3, corresponding to a potential over-estimation of the diffusivity in uranium oxycarbide (UCO) by a factor of up to 250. For intact particles, whose release is much lower, the over-prediction is by a factor of up to 100, which could be attributed to an over-estimated diffusivity in SiC by about 40% on average. The release of strontium from intact particles is also over-predicted by PARFUME, which also points towards an over-estimated diffusivity of strontium in either SiC or UCO, or possibly both. The measured strontium fractional release from intact particles varied considerably from compact to compact, making it difficult to assess the effective over-estimation of the diffusivities. Moreover, the release of strontium from particles with failed SiC is difficult to observe experimentally due to the release from intact particles, preventing any conclusions to be made on the accuracy or validity of the PARFUME predictions and the modeled diffusivity of strontium in UCO.« less

Comparison of silver, cesium, and strontium release predictions using PARFUME with results from the AGR-1 irradiation experiment

NASA Astrophysics Data System (ADS)

Collin, Blaise P.; Petti, David A.; Demkowicz, Paul A.; Maki, John T.

2015-11-01

The PARFUME (PARticle FUel ModEl) code was used to predict the release of fission products silver, cesium, and strontium from tristructural isotropic coated fuel particles and compacts during the first irradiation experiment (AGR-1) of the Advanced Gas Reactor Fuel Development and Qualification program. The PARFUME model for the AGR-1 experiment used the fuel compact volume average temperature for each of the 620 days of irradiation to calculate the release of silver, cesium, and strontium from a representative particle for a select number of AGR-1 compacts. Post-irradiation examination (PIE) measurements provided data on release of these fission products from fuel compacts and fuel particles, and retention of silver in the compacts outside of the silicon carbide (SiC) layer. PARFUME-predicted fractional release of silver, cesium, and strontium was determined and compared to the PIE measurements. For silver, comparisons show a trend of over-prediction at low burnup and under-prediction at high burnup. PARFUME has limitations in the modeling of the temporal and spatial distributions of the temperature and burnup across the compacts, which affects the accuracy of its predictions. Nevertheless, the comparisons on silver release lie in the same order of magnitude. Results show an overall over-prediction of the fractional release of cesium by PARFUME. For particles with failed SiC layers, the over-prediction is by a factor of up to 3, corresponding to a potential over-estimation of the diffusivity in uranium oxycarbide (UCO) by a factor of up to 250. For intact particles, whose release is much lower, the over-prediction is by a factor of up to 100, which could be attributed to an over-estimated diffusivity in SiC by about 40% on average. The release of strontium from intact particles is also over-predicted by PARFUME, which also points towards an over-estimated diffusivity of strontium in either SiC or UCO, or possibly both. The measured strontium fractional release from intact particles varied considerably from compact to compact, making it difficult to assess the effective over-estimation of the diffusivities. Furthermore, the release of strontium from particles with failed SiC is difficult to observe experimentally due to the release from intact particles, preventing any conclusions to be made on the accuracy or validity of the PARFUME predictions and the modeled diffusivity of strontium in UCO.

Advanced release technologies program

NASA Technical Reports Server (NTRS)

Purdy, Bill

1994-01-01

The objective of the ARTS program was to develop lighter and less expensive spacecraft ordnance and release systems that answer to the requirements of a wide variety of spacecraft applications. These improvements were to be evaluated at the spacecraft system level, as it was determined that there were substantial system-level costs associated with the present ordnance and release subsystems. New, better devices were to be developed, then flight qualified, then integrated into a flight experiment in order to prove the reliability required for their subsequent use on high-reliability spacecraft. The secondary goal of the program was to quantify the system-level benefits of these new subsystems based upon the development program results. Three non-explosive release mechanisms and one laser-diode-based ordnance system were qualified under the program. The release devices being developed were required to release high preloads because it is easier to scale down a release mechanism than to scale it up. The laser initiator developed was required to be a direct replacement for NASA Standard Initiators, since these are the most common initiator in use presently. The program began in October, 1991, with completion of the flight experiment scheduled for February, 1994. This paper provides an overview of the ARTS program, discusses the benefits of using the ARTS components, introduces the new components, compares them with conventional systems and each other, and provides recommendations on how best to implement them.

Solvent Vapor Annealing of Amorphous Carbamazepine Films for Fast Polymorph Screening and Dissolution Alteration.

PubMed

Schrode, Benedikt; Bodak, Brigitta; Riegler, Hans; Zimmer, Andreas; Christian, Paul; Werzer, Oliver

2017-09-30

Solubility enhancement and thus higher bioavailability are of great importance and a constant challenge in pharmaceutical research whereby polymorph screening and selection is one of the most important tasks. A very promising approach for polymorph screening is solvent vapor annealing where a sample is exposed to an atmosphere saturated with molecules of a specific chemical/solvent. In this work, amorphous carbamazepine thin films were prepared by spin coating, and the transformation into crystalline forms under exposure to solvent vapors was investigated. Employing grazing incidence X-ray diffraction, four distinct carbamazepine polymorphs, a solvate, and hydrates could be identified, while optical microscopy showed mainly spherulitic morphologies. In vitro dissolution experiments revealed different carbamazepine release from the various thin-film samples containing distinct polymorphic compositions: heat treatment of amorphous samples at 80 °C results in an immediate release; samples exposed to EtOH vapors show a drug release about 5 times slower than this immediate one; and all the others had intermediate release profiles. Noteworthy, even the sample of slowest release has a manifold faster release compared to a standard powder sample demonstrating the capabilities of thin-film preparation for faster drug release in general. Despite the small number of samples in this screening experiment, the results clearly show how solvent vapor annealing can assist in identifying potential polymorphs and allows for estimating their impact on properties like bioavailability.

Dynamics of Potassium Release and Adsorption on Rice Straw Residue

PubMed Central

Li, Jifu; Lu, Jianwei; Li, Xiaokun; Ren, Tao; Cong, Rihuan; Zhou, Li

2014-01-01

Straw application can not only increase crop yields, improve soil structure and enrich soil fertility, but can also enhance water and nutrient retention. The aim of this study was to ascertain the relationships between straw decomposition and the release-adsorption processes of K+. This study increases the understanding of the roles played by agricultural crop residues in the soil environment, informs more effective straw recycling and provides a method for reducing potassium loss. The influence of straw decomposition on the K+ release rate in paddy soil under flooded condition was studied using incubation experiments, which indicated the decomposition process of rice straw could be divided into two main stages: (a) a rapid decomposition stage from 0 to 60 d and (b) a slow decomposition stage from 60 to 110 d. However, the characteristics of the straw potassium release were different from those of the overall straw decomposition, as 90% of total K was released by the third day of the study. The batches of the K sorption experiments showed that crop residues could adsorb K+ from the ambient environment, which was subject to decomposition periods and extra K+ concentration. In addition, a number of materials or binding sites were observed on straw residues using IR analysis, indicating possible coupling sites for K+ ions. The aqueous solution experiments indicated that raw straw could absorb water at 3.88 g g−1, and this rate rose to its maximum 15 d after incubation. All of the experiments demonstrated that crop residues could absorb large amount of aqueous solution to preserve K+ indirectly during the initial decomposition period. These crop residues could also directly adsorb K+ via physical and chemical adsorption in the later period, allowing part of this K+ to be absorbed by plants for the next growing season. PMID:24587364

Dynamics of potassium release and adsorption on rice straw residue.

PubMed

Li, Jifu; Lu, Jianwei; Li, Xiaokun; Ren, Tao; Cong, Rihuan; Zhou, Li

2014-01-01

Straw application can not only increase crop yields, improve soil structure and enrich soil fertility, but can also enhance water and nutrient retention. The aim of this study was to ascertain the relationships between straw decomposition and the release-adsorption processes of K(+). This study increases the understanding of the roles played by agricultural crop residues in the soil environment, informs more effective straw recycling and provides a method for reducing potassium loss. The influence of straw decomposition on the K(+) release rate in paddy soil under flooded condition was studied using incubation experiments, which indicated the decomposition process of rice straw could be divided into two main stages: (a) a rapid decomposition stage from 0 to 60 d and (b) a slow decomposition stage from 60 to 110 d. However, the characteristics of the straw potassium release were different from those of the overall straw decomposition, as 90% of total K was released by the third day of the study. The batches of the K sorption experiments showed that crop residues could adsorb K(+) from the ambient environment, which was subject to decomposition periods and extra K(+) concentration. In addition, a number of materials or binding sites were observed on straw residues using IR analysis, indicating possible coupling sites for K(+) ions. The aqueous solution experiments indicated that raw straw could absorb water at 3.88 g g(-1), and this rate rose to its maximum 15 d after incubation. All of the experiments demonstrated that crop residues could absorb large amount of aqueous solution to preserve K(+) indirectly during the initial decomposition period. These crop residues could also directly adsorb K(+) via physical and chemical adsorption in the later period, allowing part of this K(+) to be absorbed by plants for the next growing season.

Effects of the 2008 high-flow experiment on water quality in Lake Powell and Glen Canyon Dam releases, Utah-Arizona

USGS Publications Warehouse

Vernieu, William S.

2010-01-01

Under the direction of the Secretary of the Interior, the U.S. Geological Survey`s Grand Canyon Monitoring and Research Center (GCMRC) conducted a high-flow experiment (HFE) at Glen Canyon Dam (GCD) from March 4 through March 9, 2008. This experiment was conducted under enriched sediment conditions in the Colorado River within Grand Canyon and was designed to rebuild sandbars, aid endangered humpback chub (Gila cypha), and benefit various downstream resources, including rainbow trout (Oncorhynchus mykiss), the aquatic food base, riparian vegetation, and archaeological sites. During the experiment, GCD discharge increased to a maximum of 1,160 m3/s and remained at that rate for 2.5 days by near-capacity operation of the hydroelectric powerplant at 736 m3/s, augmented by discharge from the river outlet works (ROW) at 424 m3/s. The ROW releases water from Lake Powell approximately 30 m below the powerplant penstock elevation and bypasses the powerplant turbines. During the HFE, the surface elevation of Lake Powell was reduced by 0.8 m. This report describes studies that were conducted before and after the experiment to determine the effects of the HFE on (1) the stratification in Lake Powell in the forebay immediately upstream of GCD and (2) the water quality of combined GCD releases and changes that occurred through the tailwater below the dam. The effects of the HFE to the water quality and stratigraphy in the water column of the GCD forebay and upstream locations in Lake Powell were minimal, compared to those during the beach/habitat-building flow experiment conducted in 1996, in which high releases of 1,273 m3/s were sustained for a 9-day period. However, during the 2008 HFE, there was evidence of increased advective transport of reservoir water at the penstock withdrawal depth and subsequent mixing of this withdrawal current with water above and below this depth. Reservoir hydrodynamics during the HFE period were largely being controlled by a winter inflow density current, which was moving through the deepest portion of the reservoir and approaching GCD near the end of the experiment. Compared to the beach/habitat-building flow experiment of 1996, the 2008 HFE had less affect on the reservoir because of the decreased volume of discharge from the dam and the different behavior of the winter inflow density current. The operation of the ROW increased the dissolved oxygen (DO) concentration of GCD releases and resulted in DO supersaturation at higher release volumes. The jets of water discharged from the ROW caused these increases. Elevated DO concentrations persisted through the tailwater of the dam to Lees Ferry. At maximum ROW operation, downstream DO concentrations increased to approximately 120 percent of saturation.

Biological instrumentation for the Viking 1975 mission to Mars.

PubMed

Klein, H P; Vishniac, W

1972-01-01

A brief introduction is given on why Mars is of interest from a biological point of view, along with an overview of the Viking 1975 mission. Details are given about the four biology instruments aboard the spacecraft and the experiments for which they are to be used. These are: the carbon assimilation experiment to determine whether the soil is biologically active, by incubation in presence of 14C-labelled CO and CO2 (known to be present in the Martian atmosphere); the label release experiment to detect metabolic activity by the release of radioactive CO2, from 14C-labelled simple organic substrates; the gas exchange experiment to detect biological activity by repeated gas chromatography analysis of soil samples; the light scattering experiment, where increase of scattering and decrease of light transmission would indicate the growth of organisms. Examples are given of data obtained with terrestrial soils in these experiments.

NASA/Max Planck Institute Barium Ion Cloud Project.

NASA Technical Reports Server (NTRS)

Brence, W. A.; Carr, R. E.; Gerlach, J. C.; Neuss, H.

1973-01-01

NASA and the Max Planck Institute for Extraterrestrial Physics (MPE), Munich, Germany, conducted a cooperative experiment involving the release and study of a barium cloud at 31,500 km altitude near the equatorial plane. The release was made near local magnetic midnight on Sept. 21, 1971. The MPE-built spacecraft contained a canister of 16 kg of Ba CuO mixture, a two-axis magnetometer, and other payload instrumentation. The objectives of the experiment were to investigate the interaction of the ionized barium cloud with the ambient medium and to deduce the properties of electric fields in the proximity of the release. An overview of the project is given to briefly summarize the organization, responsibilities, objectives, instrumentation, and operational aspects of the project.

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

James P. Barry; Peter G. Brewer

OAK-B135 This report summarizes activities and results of investigations of the potential environmental consequences of direct injection of carbon dioxide into the deep-sea as a carbon sequestration method. Results of field experiments using small scale in situ releases of liquid CO2 are described in detail. The major conclusions of these experiments are that mortality rates of deep sea biota will vary depending on the concentrations of CO2 in deep ocean waters that result from a carbon sequestration project. Large changes in seawater acidity and carbon dioxide content near CO2 release sites will likely cause significant harm to deep-sea marine life.more » Smaller changes in seawater chemistry at greater distances from release sites will be less harmful, but may result in significant ecosystem changes.« less

KENNEDY SPACE CENTER, FLA. - Japanese astronaut Koichi Wakata (left) releases a tray extended from inside the Pressurized Module, or PM, that he was working with. Part of the Japanese Experiment Module (JEM), the PM provides a shirt-sleeve environment in which astronauts on the International Space Station can conduct microgravity experiments. There are a total of 23 racks, including 10 experiment racks, inside the PM providing a power supply, communications, air conditioning, hardware cooling, water control and experiment support functions. The JEM/PM is in the Space Station Processing Facility.

NASA Image and Video Library

2003-09-24

KENNEDY SPACE CENTER, FLA. - Japanese astronaut Koichi Wakata (left) releases a tray extended from inside the Pressurized Module, or PM, that he was working with. Part of the Japanese Experiment Module (JEM), the PM provides a shirt-sleeve environment in which astronauts on the International Space Station can conduct microgravity experiments. There are a total of 23 racks, including 10 experiment racks, inside the PM providing a power supply, communications, air conditioning, hardware cooling, water control and experiment support functions. The JEM/PM is in the Space Station Processing Facility.

Study on the changes of nitrogen and phosphorus release with time from sediment in Taihu Lake after ecological dredging

NASA Astrophysics Data System (ADS)

Hu, Xiaodong; Wu, Sushu; Zhu, Min; Weng, Songgan; Guo, Liuchao

2017-06-01

The changes of nitrogen and phosphorus release with time from sediment in Taihu Lake after ecological dredging were tested in laboratory. Experiment results showed that in a simulated environment of Taihu Lake, dredging was effective to reduce the endogenous pollution release, and the effect weakened gradually along with time. When the velocity of flow increased, nitrogen and phosphorus release intensity increased, so did the largest nitrogen and phosphorus emission. Considered the resedimentation, the release of nitrogen and phosphorus were similar in the area of five years after dredging and just dredging. Re-dredging should be considered.

Source Term Experiments Project (STEP): Aerosol characterization system

NASA Astrophysics Data System (ADS)

Schlenger, B. J.; Dunn, P. F.

A series of four experiments is being conducted at Argonne National Laboratory's TREAT Reactor. They were designed to provide some of the necessary data regarding magnitude and release rates of fission products from degraded fuel pins, physical and chemical characteristics of released fission products, and aerosol formation and transport phenomena. These are in pile experiments, whereby the test fuel is heated by neutron induced fission and subsequent clad oxidation in steam environments that simulate as closely as practical predicted reactor accident conditions. The test sequences cover a range of pressure and fuel heatup rate, and include the effect of Aq/In/Cd control rod material.

Reconstruction of Atmospheric Tracer Releases with Optimal Resolution Features: Concentration Data Assimilation

NASA Astrophysics Data System (ADS)

Singh, Sarvesh Kumar; Turbelin, Gregory; Issartel, Jean-Pierre; Kumar, Pramod; Feiz, Amir Ali

2015-04-01

The fast growing urbanization, industrialization and military developments increase the risk towards the human environment and ecology. This is realized in several past mortality incidents, for instance, Chernobyl nuclear explosion (Ukraine), Bhopal gas leak (India), Fukushima-Daichi radionuclide release (Japan), etc. To reduce the threat and exposure to the hazardous contaminants, a fast and preliminary identification of unknown releases is required by the responsible authorities for the emergency preparedness and air quality analysis. Often, an early detection of such contaminants is pursued by a distributed sensor network. However, identifying the origin and strength of unknown releases following the sensor reported concentrations is a challenging task. This requires an optimal strategy to integrate the measured concentrations with the predictions given by the atmospheric dispersion models. This is an inverse problem. The measured concentrations are insufficient and atmospheric dispersion models suffer from inaccuracy due to the lack of process understanding, turbulence uncertainties, etc. These lead to a loss of information in the reconstruction process and thus, affect the resolution, stability and uniqueness of the retrieved source. An additional well known issue is the numerical artifact arisen at the measurement locations due to the strong concentration gradient and dissipative nature of the concentration. Thus, assimilation techniques are desired which can lead to an optimal retrieval of the unknown releases. In general, this is facilitated within the Bayesian inference and optimization framework with a suitable choice of a priori information, regularization constraints, measurement and background error statistics. An inversion technique is introduced here for an optimal reconstruction of unknown releases using limited concentration measurements. This is based on adjoint representation of the source-receptor relationship and utilization of a weight function which exhibits a priori information about the unknown releases apparent to the monitoring network. The properties of the weight function provide an optimal data resolution and model resolution to the retrieved source estimates. The retrieved source estimates are proved theoretically to be stable against the random measurement errors and their reliability can be interpreted in terms of the distribution of the weight functions. Further, the same framework can be extended for the identification of the point type releases by utilizing the maximum of the retrieved source estimates. The inversion technique has been evaluated with the several diffusion experiments, like, Idaho low wind diffusion experiment (1974), IIT Delhi tracer experiment (1991), European Tracer Experiment (1994), Fusion Field Trials (2007), etc. In case of point release experiments, the source parameters are mostly retrieved close to the true source parameters with least error. Primarily, the proposed technique overcomes two major difficulties incurred in the source reconstruction: (i) The initialization of the source parameters as required by the optimization based techniques. The converged solution depends on their initialization. (ii) The statistical knowledge about the measurement and background errors as required by the Bayesian inference based techniques. These are hypothetically assumed in case of no prior knowledge.

Column Experiments for Radionuclide Adsorption Studies of the Culebra Dolomite: Retardation Parameter Estimation for Non-Eluted Actinide Species

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

Brown, G.O.; Lucero, D.A.; Perkins, W.G.

The U.S. Department of Energy (DOE) has been developing a nuclear waste disposal facility, the Waste Isolation Pilot Plant (WIPP), located approximately 42 km east of Carlsbad, New Mexico. The WIPP is designed to demonstrate the safe disposal of transuranic wastes produced by the defense nuclear-weapons program. Performance assessment analyses (U.S. DOE, 1996) indicate that human intrusion by inadvertent and intermittent drilling for resources provide the only credible mechanisms for significant releases of radionuclides horn the disposal system. These releases may occur by five mechanisms: (1) cuttings, (2) cavings, (3) spallings, (4) direct brine releases, and (5) long-term brine releases.more » The first four mechanisms could result in immediate release of contaminant to the accessible environment. For the last mechanism, migration pathways through the permeable layers of rock above the Salado are important, and major emphasis is placed on the Culebra Member of the Rustler Formation because this is the most transmissive geologic layer in the disposal system. For reasons of initial quantity, half-life, and specific radioactivity, certain isotopes of Th, U, Am, and Pu would dominate calculated releases from the WIPP. In order to help quanti~ parameters for the calculated releases, radionuclide transport experiments have been carried out using five intact-core columns obtained from the Culebra dolomite member of the Rustler Formation within the Waste Isolation Pilot Plant (WIPP) site in southeastern New Mexico. This report deals primarily with results of mathematical analyses related to the retardation of %J%, 24%, and 24'Am in two of these cores (B-Core - VPX26-11A and C-Core - VPX28-6C). All B-Core transport experiments were done using Culebra-simukmt brine relevant to the core recovery location (the WIPP air-intake shaft - AIS). Most experiments with C-Core were done with AIS brine with some admixture of a brine composition (ERDA-6) that simulated deeper formation brines. No significant changes in transport behavior were observed for changes in brine. Hydraulic characteristics (i.e., apparent porosity and apparent dispersion coefficient) for the cores were obtained via experiments using conservative tracer `Na. Elution experiments carried out over periods of a few days with tracers `*U and %Np indicated that these tracers were weakly retarded as indicated by delayed elution of these species. Elution experiments with tracers `%, 24'Pu, and 24'Ani were performed, but no elution of any of these species was observed in any flow experiment to date, including experiments of up to two years duration. However, B-Core was subjected to tomographic analysis from which a retardation factor can be inferred for%. Moreover, the fact of non- elution for 24*Pu and 24'Am after more than two years brine flow through C-Core can be coupled with the minimum detectable activity for each of these species to compute minimum retardation factors in C-Core. The retardation factors for all three species can then be coupled with the apparent hydraulic characteristics to estimate an apparent minimum solutionhock distribution coefficient, &, for each actinide. The specific radionuclide isotopes used in these experiments were chosen to facilitate analysis. Even though these isotopes are not necessarily the same as those that are most important to WIPP performance, they are isotopes of the same elements, and . their chemical and transport properties are therefore identical to those of isotopes in the WIPP inventory. The retardation factors and & values deduced from experimental results strongly support the contention that sorption in the Culebra provides an effective barrier to release of Th, Pu, and Am during the regulatory period.« less

Gas Release as a Deformation Signal

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

Bauer, Stephen J.

Radiogenic noble gases are contained in crustal rock at inter and intra granular sites. The gas composition depends on lithology, geologic history, fluid phases, and the aging effect by decay of U, Th, and K. The isotopic signature of noble gases found in rocks is vastly different than that of the atmosphere which is contributed by a variety of sources. When rock is subjected to stress conditions exceeding about half its yield strength, micro-cracks begin to form. As rock deformation progresses a fracture network evolves, releasing trapped noble gases and changing the transport properties to gas migration. Thus, changes inmore » gas emanation and noble gas composition from rocks could be used to infer changes in stress-state and deformation. The purpose of this study has been to evaluate the effect of deformation/strain rate upon noble gas release. Four triaxial experiments were attempted for a strain rate range of %7E10-8 /s (180,000s) to %7E 10-4/s (500s); the three fully successful experiments (at the faster strain rates) imply the following: (1) helium is measurably released for all strain rates during deformation, this release is in amounts 1-2 orders of magnitude greater than that present in the air, and (2) helium gas release increases with decreasing strain rate.« less

[Preparation of curcumin-EC sustained-release composite particles by supercritical CO2 anti-solvent technology].

PubMed

Bai, Wei-li; Yan, Ting-yuan; Wang, Zhi-xiang; Huang, De-chun; Yan, Ting-xuan; Li, Ping

2015-01-01

Curcumin-ethyl-cellulose (EC) sustained-release composite particles were prepared by using supercritical CO2 anti-solvent technology. With drug loading and yield of inclusion complex as evaluation indexes, on the basis of single factor tests, orthogonal experimental design was used to optimize the preparation process of curcumin-EC sustained-release composite particles. The experiments such as drug loading, yield, particle size distribution, electron microscope analysis (SEM) , infrared spectrum (IR), differential scanning calorimetry (DSC) and in vitro dissolution were used to analyze the optimal process combination. The orthogonal experimental optimization process conditions were set as follows: crystallization temperature 45 degrees C, crystallization pressure 10 MPa, curcumin concentration 8 g x L(-1), solvent flow rate 0.9 mL x min(-1), and CO2 velocity 4 L x min(-1). Under the optimal conditions, the average drug loading and yield of curcumin-EC sustained-release composite particles were 33.01% and 83.97%, and the average particle size of the particles was 20.632 μm. IR and DSC analysis showed that curcumin might complex with EC. The experiments of in vitro dissolution showed that curcumin-EC composite particles had good sustained-release effect. Curcumin-EC sustained-release composite particles can be prepared by supercritical CO2 anti-solvent technology.

[Effect on iron release in drinking water distribution systems].

PubMed

Niu, Zhang-bin; Wang, Yang; Zhang, Xiao-jian; Chen, Chao; Wang, Sheng-hui

2007-10-01

Batch-scale experiments were done to quantitatively study the effect of inorganic chemical parameters on iron release in drinking water distribution systems. The parameters include acid-base condition, oxidation-reduction condition, and neutral ion condition. It was found that the iron release rate decreased with pH, alkalinity, the concentration of dissolved oxygen increasing, and the iron release rate increased with the concentration of chloride increasing. The theoretical critical formula of iron release rate was elucidated. According to the formula, the necessary condition for controlling iron release is that pH is above 7.6, the concentration of alkalinity and dissolved oxygen is more than 150 mg/L and 2 mg/L, and the concentration of chloride is less than 150 mg/L of distributed water.

Release of "Bella" white bean cultivar

USDA-ARS?s Scientific Manuscript database

"Bella" Reg. No. GP-___, PI ______) is a multiple disease resistant white bean (Phaseolus vulgaris L.) cultivar, adapted to the humid tropics that was developed and released cooperatively by the University of Puerto Rico Agricultural Experiment Station and the USDA-ARS. The breeding objective was to...

The Effects of Neutral Gas Release on Vehicle Charging: Experiment and Theory

NASA Astrophysics Data System (ADS)

Walker, D. N.; Amatucci, W. E.; Bowles, J. H.; Fernsler, R. F.; Siefring, C. L.; Antoniades, J. A.; Keskinen, M. J.

1998-11-01

This paper describes an experimental and theoretical research effort related to the mitigation of spacecraft charging by Neutral Gas Release (NGR). The Space Power Experiments Aboard Rockets programs (SPEAR I and III) [Mandel et al., 1998; Berg et al., 1995] and other earlier efforts have demonstrated that NGR is an effective method of controlling discharges in space. The laboratory experimentswere conducted in the large volume Space Physics Simulation Chamber (SPSC) at the Naval Research Laboratory (NRL). A realistic near-earth space environment can be simulated in this device for whichminimumscalingneeds to be performedtorelate the data to space plasma regimes. This environment is similar to that encountered by LEO spacecraft, e.g., the Space Station, Shuttle, and high inclination satellites. The experimental arrangement consists of an aluminum cylinder which can be biased to high negative voltage (0.4 kV

Novel device for continuous spatial control and temporal delivery of nitric oxide for in vitro cell culture☆

PubMed Central

Romanowicz, Genevieve E.; He, Weilue; Nielsen, Matthew; Frost, Megan C.

2013-01-01

Nitric oxide (NO) is an ubiquitous signaling molecule of intense interest in many physiological processes. Nitric oxide is a highly reactive free radical gas that is difficult to deliver with precise control over the level and timing that cells actually experience. We describe and characterize a device that allows tunable fluxes and patterns of NO to be generated across the surface upon which cells are cultured. The system is based on a quartz microscope slide that allows for controlled light levels to be applied to a previously described photosensitive NO-releasing polydimethylsiloxane (PDMS). Cells are cultured in separate wells that are either NO-releasing or a chemically similar PDMS that does not release NO. Both wells are then top coated with DowCorning RTV-3140 PDMS and a polydopamine/gelatin layer to allow cells to grow in the culture wells. When the waveguide is illuminated, the surface of the quartz slide propagates light such that the photosensitive polymer is evenly irradiated and generates NO across the surface of the cell culture well and no light penetrates into the volume of the wells where cells are growing. Mouse smooth muscle cells (MOVAS) were grown in the system in a proof of principle experiment, whereby 60% of the cells were present in the NO-releasing well compared to control wells after 17 h. The compelling advantage of illuminating the NO-releasing polymers with the waveguide system is that light can be used to tunably control NO release while avoiding exposing cells to optical radiation. This device provides means to quantitatively control the surface flux, timing and duration of NO cells experience and allows for systematic study of cellular response to NO generated at the cell/surface interface in a wide variety of studies. PMID:24024168

Bringing it all back home: Understanding the medical difficulties encountered by newly released prisoners in New Orleans, Louisiana - a qualitative study.

PubMed

Vail, William Lee; Niyogi, Anjali; Henderson, Norris; Wennerstrom, Ashley

2017-07-01

Formerly incarcerated persons (FIPs) face a disproportionate risk of death and serious illness in the immediate post-release period. Therefore, it is a critical time to initiate community-based care for chronic illnesses and behavioural disorders. Little is known about the unique transitional health and social support needs of FIPs in Louisiana, which has the highest incarceration rate in the world. As the average age of prisoners in the United States rises, the release of older prisoners with chronic conditions will become increasingly common. The aim of this study was to explore the healthcare experiences of FIPs in Louisiana in order to inform delivery of services tailored to this population. This research was done in partnership with a community organisation that advocates for restoration of voting rights to FIPs and helps newly released individuals transition back into society. This organisation identified FIPs in the Greater New Orleans area, and from January to May 2015, we conducted 24 semi-structured, in-person, audio-recorded interviews at the community organisation's transitional living facility. The interviews assessed FIPs' experiences with and barriers to receiving healthcare during and after incarceration. These discussions also explored FIPs' desires for services and attitudes towards health and healthcare. Interviews were transcribed and independently coded by two researchers. Interviewees reported negative experiences with healthcare during incarceration, and limited health guidance during the pre-release process. Post-release concerns included lack of insurance, difficulty accessing care and medication, and interest in learning about healthy lifestyles. Results suggest a need for a formalised system of transitional healthcare for FIPs. Findings are being used to inform a pilot transitional care clinic in New Orleans, Louisiana. © 2017 John Wiley & Sons Ltd.

The potent inhibition of vapiprost, a novel thromboxane A2 receptor antagonist, on the secondary aggregation and ATP release of human platelets.

PubMed

Horie, S; Yamada, M; Satoh, M; Noritake, S; Hiraishi, S; Kizaki, K; Kurusu, O; Nakahara, T; Ishii, H; Kazama, M

1997-06-01

The inhibitory effects of vapiprost hydrochloride (vapiprost), a novel thromboxane A2 receptor antagonist, on platelet aggregation and ATP release were studied using platelet rich plasma (PRP) of humans, guinea pigs, rabbits and rats. In in vitro experiments with human platelet, vapiprost inhibited the aggregation and ATP release stimulated with U-46619, collagen or arachidonic acid (AA) at an IC50 of less than 2.1 x 10(-8) M. Vapiprost did not inhibit the primary aggregation or ATP release of human platelets stimulated with adenosine 5'-diphosphate (ADP), epinephrine (Epi) or platelet activating factor (PAF), but inhibited the secondary aggregation stimulated with those agonists at an IC50 of less than 1.3 x 10(-7) M. The sensitivity of platelets in various species of animals to vapiprost was in the following order: human > or = guinea pigs > rats > rabbits. In ex vivo experiments with guinea pigs which received a single oral dose of vapiprost, the agent demonstrated strong inhibition of ATP release from platelets stimulated with U-46619, collagen or AA at an ID50 of less than 25.8 micrograms/kg. These inhibitory effects were observed within 30 min and sustained for 24 h at a single dosage of 5 mg/kg of vapiprost. In AA-induced pulmonary infarction models of mice, the sudden death rates decreased significantly with the oral administration of 10 mg/kg or more of vapiprost. These results indicate that vapiprost effectively inhibits the secondary aggregation and ATP release of human platelets stimulated with various agonists, and that guinea pig and human platelets are similar in response to vapiprost. Furthermore, it was demonstrated in ex vivo experiments with guinea pigs that the inhibitory action of vapiprost appears rapidly and lasts for long periods.

Analysis and Evaluation of Deployment Mechanism of a Tiny Rover in a Microgravity by Drop Tower Experiments

NASA Astrophysics Data System (ADS)

Nagaoka, Kenji; Yano, Hajime; Yoshimitsu, Tetsuo; Yoshida, Kazuya; Kubota, Takashi; Adachi, Tadashi; Kurisu, Masamitsu; Yatsunami, Hiroyuki; Kuroda, Yoji

This presentation introduces the analysis and evaluation of a deployment mechanism of a tiny rover by ZARM drop tower experiments. The mechanism is installed on the MINERVA-II2 system in the Hayabusa-2 project performed by JAXA. The MINERVA-II2 system includes a small exploration rover, and the rover will be released from the Hayabusa-2 spacecraft to the asteroid surface. After the rover lands on the surface, it will move over the surface and conduct scientific measurements. To achieve such a challenging mission, the deployment mechanism of the rover is one of the significant components. In particular, controlling the rover's landing velocity against the asteroid surface is required with high-reliability mechanism. In the MINERVA-II2 system, a reliable deployment mechanism using a metal spring is installed. By the simple mechanism, the rover's releasing velocity will be controlled within a required value. Although the performance evaluation and analysis are necessary before launch, it is difficult to experiment the deployment performance three-dimensionally on ground. In the MINERVA-II2 project, with the cooperation of ZARM, DLR and JAXA, we conducted microgravity experiments using a ZARM drop tower to examine the deployment performance in a three-dimensional microgravity. During the experiments, motion of the deployment mechanism and the rover were captured by an external camera mounted on the dropping chamber. After the drop, we analyzed the rover's releasing velocity based on image processing of the camera data. The experimental results confirmed that the deployment mechanism is feasible and reliable for controlling the rover's releasing velocity. In addition to the experiments, we analyzed a mechanical friction resistance of the mechanism from a theoretical viewpoint. These results contribute to design of spring stiffness and feedback to the development of the MINERVA-II2 flight model. Finally, the drop tower experiments were accomplished based on the agreement on the Hayabusa-2 project by DLR-JAXA. The chamber for the experiments was used, which was developed by the Hayabusa-2 project. In the experiments, we received technical and operations supports from ZARM. We sincerely express our acknowledgement to ZARM, DLR and JAXA.

Active experiments in space plasmas; Symposium D4.1 of Commission D, COSPAR Scientific Assembly, 30th, Hamburg, Germany, July 11-21, 1994

NASA Astrophysics Data System (ADS)

Rietveld, M. T.

1995-07-01

Papers from the conference are presented and cover the following topics: ion and electron beams; ionospheric modification; spacecraft interactions; chemical releases; and plasma waves. Auroras and plasma emissions are reported from electron beam injection experiments on the EXCEDE 3 rocket and APEX satellite respectively. The important parameters affecting the charging of spacecraft during the operation of electron guns is covered. The Active Magnetospheric Particle Acceleration Satellite (AMPAS) mission utilizing dual-payload tethered satellites and both up and downward directed electron beams is proposed to study the magnetosphere. Recent results and associated theories from the Sura, Arecibo and Troms ionospheric heating facitlites are presented. The effects of neutral gases on spacecraft charging are examined in a series of rocket flights. Many results from the Combined Release and Radiation Effects Satellite chemical release experiments are presented. For individual titles, see A95-83500 through A95-83535.

Single processing step toward injectable sustained-release formulations of Triptorelin based on a novel degradable semi-solid polymer.

PubMed

Asmus, Lutz R; Kaufmann, Béatrice; Melander, Louise; Weiss, Torsten; Schwach, Grégoire; Gurny, Robert; Möller, Michael

2012-08-01

Poly(lactic acid) is a widely used polymer for parenteral sustained-release formulations. But its solid state at room-temperature complicates the formulation process, and elaborate formulation systems like microparticles and self-precipitating implants are required for administration. In contrast, hexylsubstituted poly(lactic acid) (hexPLA) is a viscous, biodegradable liquid, which can simply be mixed with the active compound. In this study, the feasibility to prepare injectable suspension formulations with peptides was addressed on the example of the GnRH-agonist Triptorelin. Two formulation procedures, of which one was a straight forward one-step cryo-milling-mixing process, were compared regarding the particle size of the peptide in the polymer matrix, distribution, and drug release. This beneficial method resulted in a homogeneous formulation with an average particle diameter of the incorporated Triptorelin of only 4.1 μm. The rheological behavior of the Triptorelin-hexPLA formulations was assessed and showed thixotropic and shear-thinning behavior. Viscosity and injectability were highly dependent on the drug loading, polymer molecular weight, and temperature. Nine formulations with drug loadings from 2.5% to 10% and hexPLA molecular weights between 1500 and 5000 g/mol were investigated in release experiments, and all displayed a long-term release for over 3 months. Formulations with hexPLA of 1500 g/mol showed a viscosity-dependent release and hexPLA-Triptorelin formulations of over 2500 g/mol a molecular weight-dependent release profile. In consequence, the burst release and rate of release were controllable by adapting the drug loading and the molecular weight of the hexPLA. The degradation characteristics of the hexPLA polymer during the in vitro release experiment were studied by following the molecular weight decrease and weight loss. Triptorelin-hexPLA formulations had interesting sustained-release characteristics justifying further investigations in the drug-polymer interactions and the in vivo behavior. Copyright © 2012 Elsevier B.V. All rights reserved.

Higher mobility of butterflies than moths connected to habitat suitability and body size in a release experiment

PubMed Central

Kuussaari, Mikko; Saarinen, Matias; Korpela, Eeva-Liisa; Pöyry, Juha; Hyvönen, Terho

2014-01-01

Mobility is a key factor determining lepidopteran species responses to environmental change. However, direct multispecies comparisons of mobility are rare and empirical comparisons between butterflies and moths have not been previously conducted. Here, we compared mobility between butterflies and diurnal moths and studied species traits affecting butterfly mobility. We experimentally marked and released 2011 butterfly and 2367 moth individuals belonging to 32 and 28 species, respectively, in a 25 m × 25 m release area within an 11-ha, 8-year-old set-aside field. Distance moved and emigration rate from the release habitat were recorded by species. The release experiment produced directly comparable mobility data in 18 butterfly and 9 moth species with almost 500 individuals recaptured. Butterflies were found more mobile than geometroid moths in terms of both distance moved (mean 315 m vs. 63 m, respectively) and emigration rate (mean 54% vs. 17%, respectively). Release habitat suitability had a strong effect on emigration rate and distance moved, because butterflies tended to leave the set-aside, if it was not suitable for breeding. In addition, emigration rate and distance moved increased significantly with increasing body size. When phylogenetic relatedness among species was included in the analyses, the significant effect of body size disappeared, but habitat suitability remained significant for distance moved. The higher mobility of butterflies than geometroid moths can largely be explained by morphological differences, as butterflies are more robust fliers. The important role of release habitat suitability in butterfly mobility was expected, but seems not to have been empirically documented before. The observed positive correlation between butterfly size and mobility is in agreement with our previous findings on butterfly colonization speed in a long-term set-aside experiment and recent meta-analyses on butterfly mobility. PMID:25614794

Smectite clays in Mars soil: evidence for their presence and role in Viking biology experimental results.

PubMed

Banin, A; Rishpon, J

1979-12-01

Various chemical, physical and geological observations indicate that smectite clays are probably the major components of the Martian soil. Satisfactory ground-based chemical simulation of the Viking biology experimental results was obtained with the smectite clays nontronite and montmorillonite when they contained iron and hydrogen as adsorbed ions. Radioactive gas was released from the medium solution used in the Viking Labeled Release (LR) experiment when interacted with the clays, at rates and quantities similar to those measured by Viking on Mars. Heating of the active clay (mixed with soluble salts) to 160 degrees C in CO2 atmosphere reduced the decomposition activity considerably, again, as was observed on Mars. The decomposition reaction in LR experiment is postulated to be iron-catalyzed formate decomposition on the clay surface. The main features of the Viking Pyrolytic Release (PR) experiment were also simulated recently (Hubbard, 1979) which the iron clays, including a relatively low '1st peak' and significant '2nd peak'. The accumulated observations on various Martian soil properties and the results of simulation experiments, thus indicate that smectite clays are major and active components of the Martian soil. It now appears that many of the results of the Viking biology experiments can be explained on the basis of their surface activity in catalysis and adsorption.

Shock loading and release behavior of silicon nitride

NASA Astrophysics Data System (ADS)

Kawai, Nobuaki; Tsuru, Taiki; Hidaka, Naoto; Liu, Xun; Mashimo, Tsutomu

2015-06-01

Shock-reshock and shock-release experiments were performed on silicon nitride ceramics above and below its phase transition pressure. Experimental results clearly show the occurrence of elastic-plastic transition and phase transition during initial shock loading. The HEL and phase transition stress are determined as 11.6 GPa and 34.5 GPa, respectively. Below the phase transition point, the reshock profile consists of the single shock with short rise time, while the release profile shows the gradual release followed by more rapid one. Above the phase transition point, reshock and release behavior varies with the initial shock stress. In the case of reshock and release from about 40 GPa, the reshock structure is considerably dispersed, while the release structure shows rapid release. In the reshock profile from about 50 GPa, the formation of the shock wave with the small ramped precursor is observed. And, the release response from same condition shows initial gradual release and subsequent quite rapid one. These results would provide the information about how phase transformation kinetics effects on the reshock and release behavior.

Words and Pictures as Distinct Encoding Categories in Short-Term Memory

ERIC Educational Resources Information Center

Wells, J. Elisabeth

1973-01-01

Results of this experiment show a considerable release from proactive inhibition with a shift from words to pictures or pictures to words, thus adding one more change to the considerable number of category changes which produce the release phenomenon. (Author/CB)

Notice of release of sugarcane variety Ho 05-961

USDA-ARS?s Scientific Manuscript database

The release of high-yielding varieties to growers is important to the sustainability of all commodity industries. To that end, the Agricultural Research Service of the United States Department of Agriculture, the Louisiana Agricultural Experiment Station of the LSU Agricultural Center, and the Amer...

Ultrasound Stimulation of Insulin Release from Pancreatic Beta Cells

NASA Astrophysics Data System (ADS)

Suarez Castellanos, Ivan M.

Type 2 diabetes (T2D) mellitus is a complex metabolic disease that has reached epidemic proportions in the United States and around the world. Controlling T2D is often difficult as pharmacological management routinely requires complex therapy with multiple medications, and loses its effectiveness over time. The objective of this dissertation was to explore a novel, non-pharmacological approach that utilizes the application of ultrasound energy to stimulate insulin release. Our experiments have focused on determination of effectiveness and safety of ultrasound application in stimulation of insulin release from the pancreatic beta cells. Our results showed that ultrasound treatment, applied at frequencies of 800 kHz and 1 MHz and intensities of 0.5 W/cm2 and 1 W/cm2, did not produce any significant effects on cell viability compared to sham group as assessed with trypan blue dye exclusion test and MTT cytotoxicity assay. ELISA quantification of insulin release from beta cells resulting from ultrasound treatment showed clinically-significant amounts of released insulin as compared to sham-treated beta cells. Carbon fiber amperometry detection of secretory events from dopamine-loaded beta cells treated with ultrasound showed that release of secretory content could be temporally controlled by careful selection of ultrasound parameters. Both ELISA and amperometry experiments demonstrated that ultrasound-stimulated insulin release is a calcium-dependent process, potentially mediated by the mechanical effects of ultrasound. This study demonstrated that therapeutic ultrasound is a technique capable of stimulating the release of insulin from pancreatic beta cells in a safe, effective and controlled manner.

The Case for Extant Life on Mars and Its Possible Detection by the Viking Labeled Release Experiment.

PubMed

Levin, Gilbert V; Straat, Patricia Ann

2016-10-01

The 1976 Viking Labeled Release (LR) experiment was positive for extant microbial life on the surface of Mars. Experiments on both Viking landers, 4000 miles apart, yielded similar, repeatable, positive responses. While the authors eventually concluded that the experiment detected martian life, this was and remains a highly controversial conclusion. Many believe that the martian environment is inimical to life and the LR responses were nonbiological, attributed to an as-yet-unidentified oxidant (or oxidants) in the martian soil. Unfortunately, no further metabolic experiments have been conducted on Mars. Instead, follow-on missions have sought to define the martian environment, mostly searching for signs of water. These missions have collected considerable data regarding Mars as a habitat, both past and present. The purpose of this article is to consider recent findings about martian water, methane, and organics that impact the case for extant life on Mars. Further, the biological explanation of the LR and recent nonbiological hypotheses are evaluated. It is concluded that extant life is a strong possibility, that abiotic interpretations of the LR data are not conclusive, and that, even setting our conclusion aside, biology should still be considered as an explanation for the LR experiment. Because of possible contamination of Mars by terrestrial microbes after Viking, we note that the LR data are the only data we will ever have on biologically pristine martian samples. Key Words: Extant life on Mars-Viking Labeled Release experiment-Astrobiology-Extraterrestrial life-Mars. Astrobiology 16, 798-810.

Assessment of potential climate change impacts on peatland dissolved organic carbon release and drinking water treatment from laboratory experiments.

PubMed

Tang, R; Clark, J M; Bond, T; Graham, N; Hughes, D; Freeman, C

2013-02-01

Catchments draining peat soils provide the majority of drinking water in the UK. Over the past decades, concentrations of dissolved organic carbon (DOC) have increased in surface waters. Residual DOC can cause harmful carcinogenic disinfection by-products to form during water treatment processes. Increased frequency and severity of droughts combined with and increased temperatures expected as the climate changes, have potentials to change water quality. We used a novel approach to investigate links between climate change, DOC release and subsequent effects on drinking water treatment. We designed a climate manipulation experiment to simulate projected climate changes and monitored releases from peat soil and litter, then simulated coagulation used in water treatment. We showed that the 'drought' simulation was the dominant factor altering DOC release and affected the ability to remove DOC. Our results imply that future short-term drought events could have a greater impact than increased temperature on DOC treatability. Copyright © 2012 Elsevier Ltd. All rights reserved.

Development of ligustrazine hydrochloride carboxymethyl chitosan and collagen microspheres: Formulation optimization, characterization, and vitro release

PubMed Central

Lin, Qiang; Huo, Qing; Qin, Yingzhe; Zhao, Zhuo; Tao, Fengyun

2017-01-01

ABSTRACT This study investigates the preparation of ligustrazine hydrochloride carboxymethyl chitosan and collagen microspheres. This experiment investigates effects of the ratio of carboxymethyl chitosan and collagen blend, water to oil ratio, stirring speed, and other factors on the microsphere properties. The experiment had the following conditions: a 1:2 proportion of carboxymethyl chitosan and collagen, a 1:2 proportion of drugs and materials, a 5:1 proportion of oil phase and water phase, 0.5% of span80, a 600r/min stirring speed, 3 ml of a cross-linking agent, 3 h of cross-linking curing, 1.25 ± 0.05 mm diameter LTH microcapsules, a 54.08% envelop rate, and a 14.16% carrier rate. The microspheres release rate reached 66% within 1 h, then steadily released within 5 h in vitro. The experimental results showed that the ligustrazine hydrochloride microsphere production process was stable and exhibited a good release effect compared with other ligustrazine hydrochloride tablets and pills. PMID:27689792

Mechanical behavior of cellulose microfibrils in tension wood, in relation with maturation stress generation.

PubMed

Clair, Bruno; Alméras, Tancrède; Yamamoto, Hiroyuki; Okuyama, Takashi; Sugiyama, Junji

2006-08-01

A change in cellulose lattice spacing can be detected during the release of wood maturation stress by synchrotron x-ray diffraction experiment. The lattice strain was found to be the same order of magnitude as the macroscopic strain. The fiber repeat distance, 1.033 nm evaluated for tension wood after the release of maturation stress was equal to the conventional wood values, whereas the value before stress release was larger, corresponding to a fiber repeat of 1.035 nm, nearly equal to that of cotton and ramie. Interestingly, the fiber repeat varied from 1.033 nm for wood to 1.040 nm for algal cellulose, with an increasing order of lateral size of cellulose microfibrils so far reported. These lines of experiments demonstrate that, before the stress release, the cellulose was in a state of tension, which is, to our knowledge, the first experimental evidence supporting the assumption that tension is induced in cellulose microfibrils.

Translocations as Experiments in the Ecological Resilience of an Asocial Mega-Herbivore

PubMed Central

Linklater, Wayne L.; Gedir, Jay V.; Law, Peter R.; Swaisgood, Ron R.; Adcock, Keryn; du Preez, Pierre; Knight, Michael H.; Kerley, Graham I. H.

2012-01-01

Species translocations are remarkable experiments in evolutionary ecology, and increasingly critical to biodiversity conservation. Elaborate socio-ecological hypotheses for translocation success, based on theoretical fitness relationships, are untested and lead to complex uncertainty rather than parsimonious solutions. We used an extraordinary 89 reintroduction and 102 restocking events releasing 682 black rhinoceros (Diceros bicornis) to 81 reserves in southern Africa (1981–2005) to test the influence of interacting socio-ecological and individual characters on post-release survival. We predicted that the socio-ecological context should feature more prominently after restocking than reintroduction because released rhinoceros interact with resident conspecifics. Instead, an interaction between release cohort size and habitat quality explained reintroduction success but only individuals' ages explained restocking outcomes. Achieving translocation success for many species may not be as complicated as theory suggests. Black rhino, and similarly asocial generalist herbivores without substantial predators, are likely to be resilient to ecological challenges and robust candidates for crisis management in a changing world. PMID:22295100

Translocations as experiments in the ecological resilience of an asocial mega-herbivore.

PubMed

Linklater, Wayne L; Gedir, Jay V; Law, Peter R; Swaisgood, Ron R; Adcock, Keryn; du Preez, Pierre; Knight, Michael H; Kerley, Graham I H

2012-01-01

Species translocations are remarkable experiments in evolutionary ecology, and increasingly critical to biodiversity conservation. Elaborate socio-ecological hypotheses for translocation success, based on theoretical fitness relationships, are untested and lead to complex uncertainty rather than parsimonious solutions. We used an extraordinary 89 reintroduction and 102 restocking events releasing 682 black rhinoceros (Diceros bicornis) to 81 reserves in southern Africa (1981-2005) to test the influence of interacting socio-ecological and individual characters on post-release survival. We predicted that the socio-ecological context should feature more prominently after restocking than reintroduction because released rhinoceros interact with resident conspecifics. Instead, an interaction between release cohort size and habitat quality explained reintroduction success but only individuals' ages explained restocking outcomes. Achieving translocation success for many species may not be as complicated as theory suggests. Black rhino, and similarly asocial generalist herbivores without substantial predators, are likely to be resilient to ecological challenges and robust candidates for crisis management in a changing world.

The Effect of Birthrate Granularity on the Release- to- Birth Ratio for the AGR-1 In-core Experiment

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

Dawn Scates; John Walter

The AGR-1 Advanced Gas Reactor (AGR) tristructural-isotropic-particle fuel experiment underwent 13 irradiation intervals from December 2006 until November 2009 within the Idaho National Laboratory Advanced Test Reactor in support of the Next Generation Nuclear Power Plant program. During this multi-year experiment, release-to-birth rate ratios were computed at the end of each operating interval to provide information about fuel performance. Fission products released during irradiation were tracked daily by the Fission Product Monitoring System using 8-hour measurements. Birth rates calculated by MCNP with ORIGEN for as-run conditions were computed at the end of each irradiation interval. Each time step in MCNPmore » provided neutron flux, reaction rates and AGR-1 compact composition, which were used to determine birth rates using ORIGEN. The initial birth-rate data, consisting of four values for each irradiation interval at the beginning, end, and two intermediate times, were interpolated to obtain values for each 8-hour activity. The problem with this method is that any daily changes in heat rates or perturbations, such as shim control movement or core/lobe power fluctuations, would not be reflected in the interpolated data and a true picture of the system would not be presented. At the conclusion of the AGR-1 experiment, great efforts were put forth to compute daily birthrates, which were reprocessed with the 8-hour release activity. The results of this study are presented in this paper.« less

The effect of birthrate granularity on the release-to-birth ratio for the AGR-1 in-core experiment

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

D. M. Scates; J. B. Walter; J. T. Maki

The AGR-1 Advanced Gas Reactor (AGR) tristructural-isotropic-particle fuel experiment underwent 13 irradiation intervals from December 2006 until November 2009 within the Idaho National Laboratory Advanced Test Reactor in support of the Next Generation Nuclear Power Plant program. During this multi-year experiment, release-to-birth rate ratios were computed at the end of each operating interval to provide information about fuel performance. Fission products released during irradiation were tracked daily by the Fission Product Monitoring System using 8-h measurements. Birth rate calculated by MCNP with ORIGEN for as-run conditions were computed at the end of each irradiation interval. Each time step in MCNPmore » provided neutron flux, reaction rates and AGR-1 compact composition, which were used to determine birth rate using ORIGEN. The initial birth-rate data, consisting of four values for each irradiation interval at the beginning, end, and two intermediate times, were interpolated to obtain values for each 8-h activity. The problem with this method is that any daily changes in heat rates or perturbations, such as shim control movement or core/lobe power fluctuations, would not be reflected in the interpolated data and a true picture of the system would not be presented. At the conclusion of the AGR-1 experiment, great efforts were put forth to compute daily birthrates, which were reprocessed with the 8-h release activity. The results of this study are presented in this paper.« less

Accumulation and release of 241Am by a macrophyte of the Yenisei River (Elodea canadensis).

PubMed

Bolsunovsky, A; Zotina, T; Bondareva, L

2005-01-01

The source of radioactive contamination of the Yenisei River floodplain, including contamination with transuranic elements, is the Mining-and-Chemical Combine of the Russian Ministry of Atomic Energy, which has for many years been producing weapons-grade plutonium. Transuranic elements have been detected not only in the soil and sediment of the river but also in the biomass of aquatic plants. This work is an investigation of accumulation and release of 241Am by a submerged macrophyte of the Yenisei River (Elodea canadensis) in laboratory experiments. In 2000-2003, laboratory experiments were carried out with biomass of E. canadensis Mich. and filtered river water. The samples were collected from the Yenisei River upstream of the discharge of the Combine's radioactive effluent. The experiments showed that 241Am is accumulated by Elodea biomass: the activity concentration of 241Am can reach 3280+/-240 Bq/g, with the concentration factor for 241Am 16 600+/-2200l/kg. Results of chemical fractionation have proved that in the course of 241Am accumulation by Elodea biomass, 241Am tightly bound to biomass increases from 11% to 27% of the total 241Am in the biomass. Release of 241Am from the decaying Elodea biomass has been evaluated experimentally. By the end of the experiment (lasting up to 127 days), the Elodea plants had lost up to 65% of their initial 241Am activity and the rate of 241Am release into the water environment reached 23 Bq/day.

Interpretation of data obtained from non-destructive and destructive post-test analyses of an intact-core column of culebra dolomite

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

Lucero, Daniel L.; Perkins, W. George

The U.S. Department of Energy (DOE) has been developing a nuclear waste disposal facility, the Waste Isolation Pilot Plant (WIPP), located approximately 42 km east of Carlsbad, New Mexico. The WIPP is designed to demonstrate the safe disposal of transuranic wastes produced by the defense nuclear-weapons program. Pefiormance assessment analyses (U.S. DOE, 1996) indicate that human intrusion by inadvertent and intermittent drilling for resources provide the only credible mechanisms for significant releases of radionuclides horn the disposal system. These releases may occur by five mechanisms: (1) cuttings, (2) cavings, (3) spallings, (4) direct brine releases, and (5) long- term brinemore » releases. The first four mechanisms could result in immediate release of contaminant to the accessible environment. For the last mechanisq migration pathways through the permeable layers of rock above the Salado are important, and major emphasis is placed on the Culebra Member of the Rustler Formation because this is the most transmissive geologic layer in the disposal system. For reasons of initial quantity, half-life, and specific radioactivity, certain isotopes of T~ U, Am, and Pu would dominate calculated releases from the WIPP. In order to help quantifi parameters for the calculated releases, radionuclide transport experiments have been carried out using five intact-core columns obtained from the Culebra dolomite member of the Rustler Formation within the Waste Isolation Pilot Pknt (WIPP) site in southeastern New Mexico. This report deals primarily with results of analyses for 241Pu and 241Am distributions developed during transport experiments in one of these cores. All intact-core column transport experiments were done using Culebra-simukmt brine relevant to the core recovery location (the WIPP air-intake shaft - AK). Hydraulic characteristics (i.e., apparent porosity and apparent dispersion coefficient) for intact-core columns were obtained via experiments using conservative tracer `Na. Elution experiments carried out over periods of a few days with tracers `2U and `?Np indicated that these tracers were weakly retarded as indicated by delayed elution of these species. Elution experiments with tracers 24% and 24*Arn were performed, but no elution of either species was observed in any flow experiment to date, including experiments of many months' duration. In order to quanti~ retardation of the non-eluted species 24*Pu and 241Arn afler a period of brine flow, non-destructive and destructive analyses of an intact-core column were carried out to determine distribution of these actinides in the rock. Analytical results indicate that the majority of the 241Am is present very near the top (injection) surface of the core (possibly as a precipitate), and that the majority of the 241Pu is dispersed with a very high apparent retardation value. The 24]Pu distribution is interpreted using a single-porosity advection-dispersion model, and an approximate retardation value is reported for this actinide. The specific radionuclide isotopes used in these experiments were chosen to facilitate analysis. Even though these isotopes are not necessarily the same as those that are most important to WIPP performance, they are isotopes of the same elements, and their chemical and transport properties are therefore identical to those of isotopes in the inventory.« less

Charge exchange contamination of CRIT-II barium CIV experiment. [critical ionization velocity in ionosphere

NASA Technical Reports Server (NTRS)

Swenson, G. R.; Mende, S. B.; Meyerott, R. E.; Rairden, R. L.

1991-01-01

Experiments have been recently performed which attempted to confirm critical ionization velocity (CIV) ionization by deploying chemicals at high velocity in the ionosphere. Specifically, the CRIT-II rocket performed a barium release in the ionosphere, where observations of Ba(+) resonant emissions following the release are believed to have resulted from the CIV process. Calculations are presented which suggest a significant fraction (if not all) of the Ba(+) observed likely resulted from charge exchange with the thermosphere ions and not through CIV processes. The results presented here are pertinent to other CIV experiments performed in the ionosphere. It is recommended that laboratory measurements should be made of the charge exchange cross section between O(+) and Ba as well as other metal vapors used in CIV experiments.

Shock-induced microstructural response of mono- and nanocrystalline SiC ceramics

NASA Astrophysics Data System (ADS)

Branicio, Paulo S.; Zhang, Jingyun; Rino, José P.; Nakano, Aiichiro; Kalia, Rajiv K.; Vashishta, Priya

2018-04-01

The dynamic behavior of mono- and nanocrystalline SiC ceramics under plane shock loading is revealed using molecular-dynamics simulations. The generation of shock-induced elastic compression, plastic deformation, and structural phase transformation is characterized at different crystallographic directions as well as on a 5-nm grain size nanostructure at 10 K and 300 K. Shock profiles are calculated in a wide range of particle velocities 0.1-6.0 km/s. The predicted Hugoniot agree well with experimental data. Results indicate the generation of elastic waves for particle velocities below 0.8-1.9 km/s, depending on the crystallographic direction. In the intermediate range of particle velocities between 2 and 5 km/s, the shock wave splits into an elastic precursor and a zinc blende-to-rock salt structural transformation wave, which is triggered by shock pressure over the ˜90 GPa threshold value. A plastic wave, with a strong deformation twinning component, is generated ahead of the transformation wave for shocks in the velocity range between 1.5 and 3 km/s. For particle velocities greater than 5-6 km/s, a single overdriven transformation wave is generated. Surprisingly, shocks on the nanocrystalline sample reveal the absence of wave splitting, and elastic, plastic, and transformation wave components are seamlessly connected as the shock strength is continuously increased. The calculated strengths 15.2, 31.4, and 30.9 GPa for ⟨001⟩, ⟨111⟩, and ⟨110⟩ directions and 12.3 GPa for the nanocrystalline sample at the Hugoniot elastic limit are in excellent agreement with experimental data.

In vitro release of adenosine triphosphate from the urothelium of human bladders with detrusor overactivity, both neurogenic and idiopathic.

PubMed

Kumar, Vivek; Chapple, Christopher R; Rosario, Derek; Tophill, Paul R; Chess-Williams, Russell

2010-06-01

There is increased evidence to suggest a role for nonadrenergic-noncholinergic neurotransmission in the pathogenesis of bladder dysfunction. In this set of experiments, we have assessed the contribution of the urothelium to purinergic activity by quantifying the amount of adenosine triphosphate (ATP) released from the urothelium of patients with idiopathic detrusor overactivity (IDO) and with neurogenic detrusor overactivity (NDO) and comparing these releases to those of controls. Bladder tissue with urodynamically and clinically proven NDO (n=8) and IDO (n=8) were included in this study. The carefully dissected urothelium was stimulated by mechanically stretching as well as electrically stimulating and the ATP; thus, release was quantified. We used a Lucy Anthos 1 luminometre (Anthos Labtec Instruments GmBH, Wals, Austria) to perform the assay. The results were analysed using Stingray software (Dazdaq Ltd, Brighton, UK). Both mechanical stretch and electric field stimulation (EFS) led to increased ATP release in both sets of tissues with overactivity compared to the controls; this rise was even more significant for the IDO urothelium (2416.7±479.8 pmol/g [p<0.005]) than for the NDO urothelium (133.1±22.4 pmol/g [p<0.01]); values for the controls were 77.6±16.2 pmol/g. ATP release following mechanical stretch was more sensitive to tetrodotoxin in bladders with NDO compared to those with IDO as well as to the controls, with ATP levels falling from 233.5±20.7 pmol/g to 107.2±11.6 pmol/g, expressed as percentage of basal levels (p<0.002). The experiments were performed in vitro, and the female patients were a mix of peri- and postmenopausal states. These experiments suggested a significant rise in ATP release from the urothelium of bladders with NDO as well as those with IDO in comparison to controls. Most of the ATP released from bladders with NDO is primarily from neuronal sources. Copyright © 2009 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Organic Carbon Release from Groundwater Sediments under Changing Geochemical Conditions

NASA Astrophysics Data System (ADS)

Tinnacher, R. M.; Bhattacharyya, A.; Fox, P. M.; Nico, P. S.

2016-12-01

Due to climate change, local weather patterns are expected to change, especially with respect to precipitation, the frequency of extreme storm water events, and `drought-like' conditions. This in turn, may affect groundwater recharge, the geochemical conditions in natural groundwater systems, and the chemical and microbiological processes involved in organic matter degradation. Besides the complexity of organic matter structures and local limitations in nutrients, the association of organic carbon with sediment minerals can strongly limit organic matter bioaccessability and degradability. In this study, we investigate how variations in groundwater chemistry, e.g. with respect to dissolved CO2 concentrations, may potentially affect the release of natural organic carbon from groundwater sediments, and render organic matter more bioaccessible. In lab-scale experiments under anaerobic conditions, aquifer sediments from the floodplain of the Colorado River (Rifle, USA) were brought into contact with fresh, organic-carbon free groundwater solutions, at natural or reduced CO2 concentration levels. During the repeated exchange of solutions at two temperature settings (room-temperature and 4 °C), supernatant solutions were characterized in terms of pH, dissolved metal and organic carbon (OC) concentrations, and potential changes in released OC characteristics. Sediment samples were evaluated for possible differences in Fe-speciation before and after the experiment based on EXAFS (bulk Fe K-edge). Preliminary results for 20 exchanges of groundwater solutions show a repeated release of low OC concentrations ( 0.5-2 mg OC/g sediment; 0.05-0.2% of sediment-associated OC) without any apparent depletion in the overall source term over 50 days. After 14 days, room-temperature samples released slightly higher OC concentrations than samples kept at 4 °C. An increase in solution pH, after switching to a `CO2-free' groundwater solution, did not trigger a higher OC release. Last, specific UV absorbance measurements for room-temperature samples suggest changes in released OC characteristics due to repeated solution exchanges. Additional sample characterization is ongoing, with the goal to elucidate potential changes in released OC characteristics over the course of the experiment.

Evaluation of the effect of sulfate, alkalinity and disinfector on iron release of iron pipe and iron corrosion scale characteristics under water quality changing condition using response surface methodology

NASA Astrophysics Data System (ADS)

Yang, Fan; Shi, Baoyou; Zhang, Weiyu; Guo, Jianbo; Wu, Nana; Liu, Xinyuan

2018-02-01

The response surface methodology (RSM), particularly Box-Behnken design model, was used in this study to evaluate the sulfate, alkalinity and free chlorine on iron release of pipe with groundwater supply history and its iron corrosion scale characteristics under water quality changing experiment. The RSM results together with response surface contour plots indicated that the iron release of pipe section reactors was positively related with Larson Ratio and free chlorine. The thin Corrosion scales with groundwater supply history upon collection site contained Fe3O4 (18%), α-FeOOH (64%), FeCO3 (9%), β-FeOOH (8%) and γ-FeOOH (5%), besides their averaged amorphous iron oxide content was 13.6%. After the RSM water quality changing experiment, Fe3O4, amorphous iron oxide and intermediate iron products (FeCO3, Green Rust (GR)) content on scale of Cl2Rs increased, while their α-FeOOH contents decreased and β-FeOOH disappeared. The high iron released Cl2Rs receiving higher LR water (1.40-2.04) contained highest FeCO3 (20%) and amorphous iron oxide (42%), while the low iron release Cl2Rs receiving lower LR water (0.52-0.73) had higher GR(6.5%) and the amorphous iron oxide (23.7%). In high LR water (>0.73), the thin and non-protective corrosion scale containing higher amorphous iron oxide, Fe(II) derived from new produced Fe3O4 or FeCO3 or GR was easy for oxidants and sulfate ions penetration, and had higher iron release. However the same unstable corrosion scale didn’t have much iron release in low LR water (≤0.73). RSM experiment indicated that iron release of these unstable corrosion scales had close relationship with water quality (Larson Ratio and disinfectant). Optimizing the water quality of new source water and using reasonable water purification measures can help to eliminate the red water case.

Return to drug use and overdose after release from prison: a qualitative study of risk and protective factors.

PubMed

Binswanger, Ingrid A; Nowels, Carolyn; Corsi, Karen F; Glanz, Jason; Long, Jeremy; Booth, Robert E; Steiner, John F

2012-01-01

Former inmates are at high risk for death from drug overdose, especially in the immediate post-release period. The purpose of the study is to understand the drug use experiences, perceptions of overdose risk, and experiences with overdose among former prisoners. This qualitative study included former prison inmates (N=29) who were recruited within two months after their release. Interviewers conducted in-person, semi-structured interviews which explored participants' experiences and perceptions. Transcripts were analyzed utilizing a team-based method of inductive analysis. The following themes emerged: 1) Relapse to drugs and alcohol occurred in a context of poor social support, medical co-morbidity and inadequate economic resources; 2) former inmates experienced ubiquitous exposure to drugs in their living environments; 3) intentional overdose was considered "a way out" given situational stressors, and accidental overdose was perceived as related to decreased tolerance; and 4) protective factors included structured drug treatment programs, spirituality/religion, community-based resources (including self-help groups), and family. Former inmates return to environments that strongly trigger relapse to drug use and put them at risk for overdose. Interventions to prevent overdose after release from prison may benefit from including structured treatment with gradual transition to the community, enhanced protective factors, and reductions of environmental triggers to use drugs.

Quantity of 135I released from the AGR-1, AGR-2, and AGR-3/4 experiments and discovery of 131I at the FPMS traps during the AGR-3/4 experiment

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

Scates, Dawn M.

2014-09-01

A series of three Advanced Gas Reactor (AGR) experiments have been conducted in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL). From 2006 through 2014, these experiments supported the development and qualification of the new U.S. tristructural isotropic (TRISO) particle fuel for Very High Temperature Reactors (VHTR). Each AGR experiment consisted of multiple fueled capsules, each plumbed for independent temperature control using a mix of helium and neon gases. The gas leaving a capsule was routed to individual Fission Product Monitor (FPM) detectors. For intact fuel particles, the TRISO particle coatings provide a substantial barrier to fission productmore » release. However, particles with failed coatings, whether because of a minute percentage of initially defective particles, those which fail during irradiation, or those designed to fail (DTF) particles, can release fission products to the flowing gas stream. Because reactive fission product elements like iodine and cesium quickly deposit on cooler capsule components and piping structures as the effluent gas leaves the reactor core, only the noble fission gas isotopes of Kr and Xe tend to reach FPM detectors. The FPM system utilizes High Purity Germanium (HPGe) detectors coupled with a thallium activated sodium iodide NaI(Tl) scintillator. The HPGe detector provides individual isotopic information, while the NaI(Tl) scintillator is used as a gross count rate meter. During irradiation, the 135mXe concentration reaching the FPM detectors is from both direct fission and by decay of the accumulated 135I. About 2.5 hours after irradiation (ten 15.3 minute 135mXe half lives) the directly produced 135mXe has decayed and only the longer lived 135I remains as a source. Decay systematics dictate that 135mXe will be in secular equilibrium with its 135I parent, such that its production rate very nearly equals the decay rate of the parent, and its concentration in the flowing gas stream will appear to decay with the parent half life. This equilibrium condition enables the determination of the amount of 135I released from the fuel particles by measurement of the 135mXe at the FPM following reactor shutdown. In this paper, the 135I released will be reported and compared to similar releases for noble gases as well as the unexpected finding of 131I deposition from intentional impure gas injection into capsule 11 of experiment AGR 3/4.« less

Effect of isopropyl myristate on the viscoelasticity and drug release of a drug-in-adhesive transdermal patch containing blonanserinEffect of isopropyl myristate on the viscoelasticity and drug release of a drug-in-adhesive transdermal patch containing blonanserinretain-->.

PubMed

Zhao, Chunyi; Quan, Peng; Liu, Chao; Li, Qiaoyun; Fang, Liang

2016-11-01

The purpose of this study was to investigate the effect of isopropyl myristate (IPM), a penetration enhancer, on the viscoelasticity and drug release of a drug-in-adhesive transdermal patch containing blonanserin. The patches were prepared with DURO-TAK ® 87-2287 as a pressure-sensitive adhesive (PSA) containing 5% ( w / w ) of blonanserin and different concentrations of IPM. An in vitro release experiment was performed and the adhesive performance of the drug-in-adhesive patches with different concentrations of IPM was evaluated by a rolling ball tack test and a shear-adhesion test. The glass transition temperature ( T g ) and rheological parameters of the drug-in-adhesive layers were determined to study the effect of IPM on the mechanical properties of the PSA. The results of the in vitro release experiment showed that the release rate of blonanserin increased with an increasing concentration of IPM. The rolling ball tack test and shear-adhesion test showed decreasing values with increasing IPM concentration. The results were interpreted on the basis of the IPM-induced plasticization of the PSA, as evidenced by a depression of the glass transition temperature and a decrease in the elastic modulus. In conclusion, IPM acted as a plasticizer on DURO-TAK ® 87-2287, and it increased the release of blonanserin and affected the adhesive properties of the PSA.

Clean Photothermal Heating and Controlled Release from Near-Infrared Dye Doped Nanoparticles without Oxygen Photosensitization.

PubMed

Guha, Samit; Shaw, Scott K; Spence, Graeme T; Roland, Felicia M; Smith, Bradley D

2015-07-21

The photothermal heating and release properties of biocompatible organic nanoparticles, doped with a near-infrared croconaine (Croc) dye, were compared with analogous nanoparticles doped with the common near-infrared dyes ICG and IR780. Separate formulations of lipid-polymer hybrid nanoparticles and liposomes, each containing Croc dye, absorbed strongly at 808 nm and generated clean laser-induced heating (no production of (1)O2 and no photobleaching of the dye). In contrast, laser-induced heating of nanoparticles containing ICG or IR780 produced reactive (1)O2, leading to bleaching of the dye and also decomposition of coencapsulated payload such as the drug doxorubicin. Croc dye was especially useful as a photothermal agent for laser-controlled release of chemically sensitive payload from nanoparticles. Solution state experiments demonstrated repetitive fractional release of water-soluble fluorescent dye from the interior of thermosensitive liposomes. Additional experiments used a focused laser beam to control leakage from immobilized liposomes with very high spatial and temporal precision. The results indicate that fractional photothermal leakage from nanoparticles doped with Croc dye is a promising method for a range of controlled release applications.

Electrical Signals in Prayer Plants (Marantaceae)? Insights into the Trigger Mechanism of the Explosive Style Movement

PubMed Central

Jerominek, Markus; Claßen-Bockhoff, Regine

2015-01-01

The explosive pollination mechanism of the prayer plants (Marantaceae) is unique among plants. After a tactile stimulus by a pollinator, the style curls up rapidly and mediates pollen exchange. It is still under discussion whether this explosive movement is released electrophysiologically, i.e. by a change in the membrane potential (as in Venus flytrap), or purely mechanically. In the present study, electrophysiological experiments are conducted to clarify the mechanism. Artificial release experiments (chemical and electrical) and electrophysiological measurements were conducted with two phylogenetically distant species, Goeppertia bachemiana (E. Morren) Borchs. & S. Suárez and Donax canniformis (G. Forst.) K. Schum. Electric responses recorded after style release by extracellular measurements are characterised as variation potentials due to their long repolarization phase and lack of self-perpetuation. In both species, chemical and electric stimulations do not release the style movement. It is concluded that the style movement in Marantaceae is released mechanically by relieving the tissue pressure. Accordingly, the variation potential is an effect of the movement and not its cause. The study exemplarily shows that fast movements in plants are not necessarily initiated by electric changes of the membrane as known from the Venus flytrap. PMID:25997015

Electrical signals in prayer plants (marantaceae)? Insights into the trigger mechanism of the explosive style movement.

PubMed

Jerominek, Markus; Claßen-Bockhoff, Regine

2015-01-01

The explosive pollination mechanism of the prayer plants (Marantaceae) is unique among plants. After a tactile stimulus by a pollinator, the style curls up rapidly and mediates pollen exchange. It is still under discussion whether this explosive movement is released electrophysiologically, i.e. by a change in the membrane potential (as in Venus flytrap), or purely mechanically. In the present study, electrophysiological experiments are conducted to clarify the mechanism. Artificial release experiments (chemical and electrical) and electrophysiological measurements were conducted with two phylogenetically distant species, Goeppertia bachemiana (E. Morren) Borchs. & S. Suárez and Donax canniformis (G. Forst.) K. Schum. Electric responses recorded after style release by extracellular measurements are characterised as variation potentials due to their long repolarization phase and lack of self-perpetuation. In both species, chemical and electric stimulations do not release the style movement. It is concluded that the style movement in Marantaceae is released mechanically by relieving the tissue pressure. Accordingly, the variation potential is an effect of the movement and not its cause. The study exemplarily shows that fast movements in plants are not necessarily initiated by electric changes of the membrane as known from the Venus flytrap.

The alpha-7 nicotinic acetylcholine receptor is involved in a direct inhibitory effect of nicotine on GnRH release: In vitro studies.

PubMed

Messi, Elio; Pimpinelli, Federica; Andrè, Valentina; Rigobello, Chiara; Gotti, Cecilia; Maggi, Roberto

2018-01-15

The activation of nicotinic cholinergic receptors (nAChR) inhibits the reproductive axis; however, it is not clear whether nicotine may directly modulate the release of hypothalamic gonadotropin-releasing hormone (GnRH). Experiments carried out in GT1-1 immortalized GnRH neurons reveal the presence of a single class of high affinity α4β2 and α7 nAchR subtypes. The exposure of GT1-1 cells to nicotine does not modify the basal accumulation of GnRH. However, nicotine was found to modify GnRH pulsatility in perifusion experiments and inhibits, the release of GnRH induced by prostaglandin E 1 or by K + -induced cell depolarization; these effects were reversed by D-tubocurarine and α-bungarotoxin. In conclusion, the results reported here indicate that: functional nAChRs are present on GT1-1 cells, the activation of the α-bungarotoxin-sensitive subclass (α7) produces an inhibitory effect on the release of GnRH and that the direct action of nicotine on GnRH neurons may be involved in reducing fertility of smokers. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation and in vitro/in vivo evaluation of gestodene (GEST) intravaginal ring.

PubMed

Li, Chunxiao; Ning, Meiying; Yao, Xiaodong; Wang, Yankun; Liu, Ying

2016-09-01

Preparation and in vitro/in vivo evaluation of gestodene (GEST) intravaginal ring (IVR) formulations which can release a constant dose of GEST during 3 weeks were investigated. In present study a reservoir gestodene intravaginal ring, including a gestodene silicone elastomer core and the non-active silicone layer, was reported, which was manufactured by reaction injection moulding at 80°C for 20 min. The raw materials compatibility experiments showed that the silicone elastomer core carrier wouldn't interact with drugs. In vitro release samples were determined by HPLC and the experiment was performed under sink conditions. The equation of cumulative release verse time was Y=64.76χ+5.44 (r=0.9998), performing zero-order release at about the target dose of 60 µg/day over 21 days. Drug release increased with temperature elevating from 45 to 55°C, which could be attributed to optimizing the prescription. In addition, the pharmacokinetic and safety studies of gestodene intravaginal ring were evaluated in female New Zealand White rabbits. The GEST in plasma was analyzed by LC-MS/MS and the results proved that the correlation between in vitro and in vivo was relatively well.

Clean Photothermal Heating and Controlled Release From Near Infrared Dye Doped Nanoparticles Without Oxygen Photosensitization

PubMed Central

Guha, Samit; Shaw, Scott K.; Spence, Graeme T.; Roland, Felicia M.; Smith, Bradley D.

2015-01-01

The photothermal heating and release properties of biocompatible organic nanoparticles, doped with a near-infrared croconaine (Croc) dye, were compared with analogous nanoparticles doped with the common near-infrared dyes ICG and IR780. Separate formulations of lipid-polymer-hybrid nanoparticles and liposomes, each containing Croc dye, absorbed strongly at 808 nm and generated clean laser-induced heating (no production of 1O2 and no photobleaching of the dye). In contrast, laser-induced heating of nanoparticles containing ICG or IR780 produced reactive 1O2 leading to bleaching of the dye and also decomposition of co-encapsulated payload such as the drug Doxorubicin. Croc dye was especially useful as a photothermal agent for laser controlled release of chemically sensitive payload from nanoparticles. Solution state experiments demonstrated repetitive fractional release of water soluble fluorescent dye from the interior of thermosensitive liposomes. Additional experiments used a focused laser beam to control leakage from immobilized liposomes with very high spatial and temporal precision. The results indicate that fractional photothermal leakage from nanoparticles doped with Croc dye is a promising method for a range of controlled release applications. PMID:26149326

HTO and OBT activity concentrations in soil at the historical atmospheric HT release site (Chalk River Laboratories).

PubMed

Kim, S B; Bredlaw, M; Korolevych, V Y

2012-01-01

Tritium is routinely released by the Chalk River Laboratories (CRL) nuclear facilities. Three International HT release experiments have been conducted at the CRL site in the past. The site has not been disturbed since the last historical atmospheric testing in 1994 and presents an opportunity to assess the retention of tritium in soil. This study is devoted to the measurement of HTO and OBT activity concentration profiles in the subsurface 25 cm of soil. In terms of soil HTO, there is no evidence from the past HT release experiments that HTO was retained. The HTO activity concentration in the soil pore water appears similar to concentrations found in background areas in Ontario. In contrast, OBT activity concentrations in soil at the same site were significantly higher than HTO activity concentrations in soil. Elevated OBT appears to reside in the top layer of the soil (0-5 cm). In addition, OBT activity concentrations in the top soil layer did not fluctuate much with season, again, quite in contrast with soil HTO. This result suggests that OBT activity concentrations retained the signature of the historical tritium releases. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

The Windy Island Soliton Experiment (WISE): Shallow Water and Basin Experiment Configuration and Preliminary Observations

DTIC Science & Technology

2009-02-19

Virginia 22203-1995 The Windy Island Soliton Experiment (WISE): Shallow Water and Basin Experiment Configuration and Preliminary Observations...case letters) The Windy Island Soliton Experiment (WISE): Shallow water and Basin Experiment Configuration and Preliminary Observations 5. FUNDING...release; distribution is unlimited 12b. DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) The Windy Islands Soliton Experiment (WISE) was

Observed chlorine concentrations during Jack Rabbit I and Lyme Bay field experiments

NASA Astrophysics Data System (ADS)

Hanna, Steven; Chang, Joseph; Huq, Pablo

2016-01-01

As part of planning for a series of field experiments where large quantities (up to 20 tons) of pressurized liquefied chlorine will be released, observations from previous chlorine field experiments are analyzed to estimate the ranges of chlorine concentrations expected at various downwind distances. In five field experiment days during the summer 2010 Jack Rabbit I (JR I) field trials, up to two tons of chlorine were released and concentrations were observed at distances, x, from 25 to 500 m. In the 1927 Lyme Bay (LB) experiments, there were four days of trials, where 3-10 tons of chlorine were released in about 15 min from the back of a ship. Concentrations were sampled at LB from four ships sailing across the cloud path at downwind distances in the range from about 350 to 3000 m. Thus, the distances from which JR I concentrations were available slightly overlapped the LB distances. One-minute arc-maximum chlorine concentrations, C (g/m3), were analyzed from four JR I trials and two LB trials. Normalized concentrations (Cu/Q) were plotted versus x (m), where u (m/s) is measured wind speed at heights of 2-10 m and Q (g/s) is continuous mass release rate. It is found that the JR I and LB Cu/Q observations smoothly merge with each other and fall along a line with approximate slope of -2 at distances beyond about 200 m (i.e., Cu/Q is proportional to x-2). At x < 200 m, where dense gas effects are more important, the slope is less (about -1.5). Most of the data points are within a factor of two of the "best-fit" line.

Longevity of controlled release fertilizer influences the growth of bedding Impatiens

USDA-ARS?s Scientific Manuscript database

Controlled-release fertilizers (CRF) have not been extensively used in floriculture production, perhaps due to lack of grower experience and research-based information with their use in herbaceous plant production. Any information about the correct use of CRF should increase growers’ confidence in ...

ATMOSPHERIC RELEASES FROM STANDARDIZED NUCLEAR POWER PLANTS: A WIND TUNNEL STUDY

EPA Science Inventory

Laboratory experiments were conducted to simulate radiopollutant effluents released to the atmosphere from two standard design nuclear power plants. The main objective of the study was to compare the dispersion in the wake of the standardized nuclear power plants with that in a s...

Notice of release of sugarcane variety HoCP 04-838

USDA-ARS?s Scientific Manuscript database

The release of high-yielding varieties to growers is important to the sustainability of all commodity industries. To that end, the Agricultural Research Service of the United States Department of Agriculture, the Louisiana Agricultural Experiment Station of the LSU Agricultural Center, and the Amer...

Supramolecular nanofibers of triamcinolone acetonide for uveitis therapy

NASA Astrophysics Data System (ADS)

Li, Xingyi; Wang, Yuqin; Yang, Chengbiao; Shi, Shuai; Jin, Ling; Luo, Zichao; Yu, Jing; Zhang, Zhaoliang; Yang, Zhimou; Chen, Hao

2014-11-01

Supramolecular nanofibers of prodrugs hold advantages for drug release due to their high drug payload, sustained and constant drug release behavior, and stimuli responsiveness. In this study, we report on a supramolecular hydrogel mainly formed by a clinically used drug triamcinolone acetonide (TA). Such a hydrogel could only be prepared via an ester bond hydrolysis process from its prodrug of succinated triamcinolone acetonide (STA). The resulting hydrogel could constantly release TA in the in vitro release experiment. The TA hydrogel possessed an excellent transscleral penetration ability, as evaluated by the in vitro transscleral transport study. The developed TA hydrogel also exhibited a great ocular compatibility in rats, as indicated by the optical coherence tomography (OCT) images, HE observation, and glial fibrillary acidic protein (GFAP) and vimentin immuno-staining assays of the retinas. Our TA hydrogel showed a decreased efficacy to inhibit ocular inflammation in the rat's experiment autoimmune uveitis (EAU) model compared to the commercial TA suspension (Transton®), but without causing complications such as high intraocular pressure and cataracts. These promising properties of the hydrogel indicated its great potential for the treatment of eye diseases.Supramolecular nanofibers of prodrugs hold advantages for drug release due to their high drug payload, sustained and constant drug release behavior, and stimuli responsiveness. In this study, we report on a supramolecular hydrogel mainly formed by a clinically used drug triamcinolone acetonide (TA). Such a hydrogel could only be prepared via an ester bond hydrolysis process from its prodrug of succinated triamcinolone acetonide (STA). The resulting hydrogel could constantly release TA in the in vitro release experiment. The TA hydrogel possessed an excellent transscleral penetration ability, as evaluated by the in vitro transscleral transport study. The developed TA hydrogel also exhibited a great ocular compatibility in rats, as indicated by the optical coherence tomography (OCT) images, HE observation, and glial fibrillary acidic protein (GFAP) and vimentin immuno-staining assays of the retinas. Our TA hydrogel showed a decreased efficacy to inhibit ocular inflammation in the rat's experiment autoimmune uveitis (EAU) model compared to the commercial TA suspension (Transton®), but without causing complications such as high intraocular pressure and cataracts. These promising properties of the hydrogel indicated its great potential for the treatment of eye diseases. Electronic supplementary information (ESI) available: Synthesis and characterization of the STA agent. SEM image of TA suspension (Transton®). See DOI: 10.1039/c4nr04761c

Corrective interpersonal experience in psychodrama group therapy: a comprehensive process analysis of significant therapeutic events.

PubMed

McVea, Charmaine S; Gow, Kathryn; Lowe, Roger

2011-07-01

This study investigated the process of resolving painful emotional experience during psychodrama group therapy, by examining significant therapeutic events within seven psychodrama enactments. A comprehensive process analysis of four resolved and three not-resolved cases identified five meta-processes which were linked to in-session resolution. One was a readiness to engage in the therapeutic process, which was influenced by client characteristics and the client's experience of the group; and four were therapeutic events: (1) re-experiencing with insight; (2) activating resourcefulness; (3) social atom repair with emotional release; and (4) integration. A corrective interpersonal experience (social atom repair) healed the sense of fragmentation and interpersonal disconnection associated with unresolved emotional pain, and emotional release was therapeutically helpful when located within the enactment of this new role relationship. Protagonists who experienced resolution reported important improvements in interpersonal functioning and sense of self which they attributed to this experience.

Binge eating as a meaningful experience in bulimia nervosa and anorexia nervosa: a qualitative analysis.

PubMed

Eli, Karin

2015-12-01

Clinical studies describe binge eating as a reaction to hunger, negative affect, or the need to dissociate. However, little is known about the meanings that women with bulimia nervosa and anorexia nervosa associate with binge eating. To examine how women with anorexia nervosa and bulimia nervosa interpret their experiences of binge eating. Sixteen women who engaged in binge eating and had been diagnosed with anorexia nervosa, bulimia nervosa, or their subclinical variants were interviewed about their experiences of eating disorder. Interview data were analyzed using phenomenologically-informed thematic analysis. Participants described binge eating as a practice through which the self experiences a sense of release, and existential emptiness is replaced by overwhelming fullness. Meaningful experiences of release and fullness are central to binge eating in bulimia nervosa and anorexia nervosa, and may contribute to the long-term maintenance of this practice.

THE URBAN DISPERSION PROGRAM ( UDP ) NYC MSG05 EXPERIMENT

EPA Science Inventory

The multi-organizational Urban Dispersion Program (UDP) has been conducting tracer release experiments at various locations within the United States. In March 2005 the UDP conducted the first NYC based experiment called Madison Square Garden -05 (MSG05). The field study involved ...

Are Radishes Really Allelopathic to Lettuce?

ERIC Educational Resources Information Center

Santaniello, Catherine M.; Koning, Ross E.

1996-01-01

Presents an experiment that challenges the claim that sprouting radish seedlings release chemicals into the environment that inhibit germination of lettuce seeds. Reports that although no simple allelopathic demonstration was observed, the experiment provides fertile ground for further experimentation in inquiry-based laboratory experiences. (JRH)

Mercury Abundances and Isotopic Compositions in the Murchison (CM) and Allende (CV)Carbonaceous Chondrites

NASA Technical Reports Server (NTRS)

Lauretta, D. S.; Klaue, B.; Blum, J. D.; Buseck, P. R.

2001-01-01

The abundance and isotopic composition of Hg was determined in bulk samples of both the Murchison (CM) and Allende (CV) carbonaceous chondrites using single- and multi-collector inductively coupled plasma mass spectrometry (ICP-MS). The bulk abundances of Hg are 294 6 15 ng/g in Murchison and 30.0 6 1.5 ng/g in Allende. These values are within the range of previous measurements of bulk Hg abundances by neutron activation analysis (NAA). Prior studies suggested that both meteorites contain isotopically anomalous Hg, with d l 96/202Hg values for the anomalous, thermal-release components from bulk samples ranging from 2260 %o to 1440 9/00 in Murchison and from 2620 9/00 to 1540 9/00 in Allende (Jovanovic and Reed, 1976a; 1976b; Kumar and Goel, 1992). Our multi-collector ICP-MS measurements suggest that the relative abundances of all seven stable Hg isotopes in both meteorites are identical to terrestrial values within 0.2 to 0.5 9/00m. On-line thermal-release experiments were performed by coupling a programmable oven with the singlecollector ICP-MS. Powdered aliquots of each meteorite were linearly heated from room temperature to 900 C over twenty-five minutes under an Ar atmosphere to measure the isotopic composition of Hg released fiom the meteorites as a h c t i o n of temperature. In separate experiments, the release profiles of S and Se were determined simultaneously with Hg to constrain the Hg distribution within the meteorites and to evaluate the possibility of Se interferences in previous NAA studies. The Hg-release patterns differ between Allende and Murchison. The Hg-release profile for Allende contains two distinct peaks, at 225" and 343"C, whereas the profile for Murchison has only one peak, at 344 C. No isotopically anomalous Hg was detected in the thermal-release experiments at a precision level of 5 to 30 9/00, depending on the isotope ratio. In both meteorites the Hg peak at ;340"C correlates with a peak in the S-release profile. This correlation suggests that Hg is associated with S-bearing phases and, thus, that HgS is a major Hg-bearing phase in both meteorites. The Hg peak at 225 C for Allende is similar to release patterns of physically adsorbed Hg on silicate and metal grains.

A vacuum microgripping tool with integrated vibration releasing capability

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

Rong, Weibin; Fan, Zenghua, E-mail: zenghua-fan@163.com; Wang, Lefeng

2014-08-01

Pick-and-place of micro-objects is a basic task in various micromanipulation demands. Reliable releasing of micro-objects is usually disturbed due to strong scale effects. This paper focuses on a vacuum micro-gripper with vibration releasing functionality, which was designed and assembled for reliable micromanipulation tasks. Accordingly, a vibration releasing strategy of implementing a piezoelectric actuator on the vacuum microgripping tool is presented to address the releasing problem. The releasing mechanism was illustrated using a dynamic micro contact model. This model was developed via theoretical analysis, simulations and pull-off force measurement using atomic force microscopy. Micromanipulation experiments were conducted to verify the performancemore » of the vacuum micro-gripper. The results show that, with the assistance of the vibration releasing, the vacuum microgripping tool can achieve reliable release of micro-objects. A releasing location accuracy of 4.5±0.5 μm and a successful releasing rate of around 100% (which is based on 110 trials) were achieved for manipulating polystyrene microspheres with radius of 35–100 μm.« less

Hindered disulfide bonds to regulate release rate of model drug from mesoporous silica.

PubMed

Nadrah, Peter; Maver, Uroš; Jemec, Anita; Tišler, Tatjana; Bele, Marjan; Dražić, Goran; Benčina, Mojca; Pintar, Albin; Planinšek, Odon; Gaberšček, Miran

2013-05-01

With the advancement of drug delivery systems based on mesoporous silica nanoparticles (MSNs), a simple and efficient method regulating the drug release kinetics is needed. We developed redox-responsive release systems with three levels of hindrance around the disulfide bond. A model drug (rhodamine B dye) was loaded into MSNs' mesoporous voids. The pore opening was capped with β-cyclodextrin in order to prevent leakage of drug. Indeed, in absence of a reducing agent the systems exhibited little leakage, while the addition of dithiothreitol cleaved the disulfide bonds and enabled the release of cargo. The release rate and the amount of released dye were tuned by the level of hindrance around disulfide bonds, with the increased hindrance causing a decrease in the release rate as well as in the amount of released drug. Thus, we demonstrated the ability of the present mesoporous systems to intrinsically control the release rate and the amount of the released cargo by only minor structural variations. Furthermore, an in vivo experiment on zebrafish confirmed that the present model delivery system is nonteratogenic.

Life sciences, biotechnology, and microgravity

NASA Technical Reports Server (NTRS)

Hymer, W. C.; Hayes, C.; Grindeland, R.; Lanhan, J. W.; Morrison, D.

1987-01-01

Growth hormone (GH) studies on rats flown aboard Spacelab 3 are discussed, and evidence for the direct effect of microgravity on cell function is reviewed. SL-3 rat GH cells were found to experience a secretory lesion (they contained more hormone per cell, but released less per cell relative to controls). Pituitary cell culture experiments on the STS-8 mission showed that GH cells did not subsequently release as much hormone as did control cells, indicating a secretory lesion. Changes in bone and muscle noted in SL-3 rats are related to GH cell findings.

Release and control of hydrogen sulfide during sludge thermal drying.

PubMed

Weng, Huanxin; Dai, Zhixi; Ji, Zhongqiang; Gao, Caixia; Liu, Chongxuan

2015-10-15

The release of hydrogen sulfide (H2S) during sludge drying is a major environmental problem because of its toxicity to human health. A series of experiments were performed to investigate the mechanisms and factors controlling the H2S release. Results of this study show that: (1) the biomass and activity of sulfate-reducing bacteria (SRB) in sludge were the major factors controlling the amount of H2S release, (2) the sludge drying temperature had an important effect on both the extent and the timing of H2S release from the sludge, and (3) decreasing sludge pH increased the H2S release. Based on the findings from this study, a new system that integrates sludge drying and H2S gas treatment was developed, by which 97.5% of H2S and 99.7% of smoke released from sludge treatments was eliminated. Copyright © 2015 Elsevier B.V. All rights reserved.

Release and control of hydrogen sulfide during sludge thermal drying

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

Weng, Huanxin; Dai, Zhixin; Ji, Zhongqiang

2015-04-15

The release of hydrogen sulfide (H2S) during sludge drying is a major environmental problem because of its toxicity to human health. A series of experiments were performed to investigate the mechanisms and factors controlling the H2S release. Results of this study show that: 1) the biomass and activity of sulfate-reducing bacteria (SRB) in sludge were the major factors controlling the amount of H2S release, 2) the sludge drying temperature had an important effect on both the extent and the timing of H2S release from the sludge, and 3) decreasing sludge pH increased the H2S release. Based on the findings frommore » this study, a new system that integrates sludge drying and H2S gas treatment was developed to reduce the amount of H2S released from sludge treatments.« less

Modeling the purging of dense fluid from a street canyon driven by an interfacial mixing flow and skimming flow

NASA Astrophysics Data System (ADS)

Baratian-Ghorghi, Z.; Kaye, N. B.

2013-07-01

An experimental study is presented to investigate the mechanism of flushing a trapped dense contaminant from a canyon by turbulent boundary layer flow. The results of a series of steady-state experiments are used to parameterize the flushing mechanisms. The steady-state experimental results for a canyon with aspect ratio one indicate that dense fluid is removed from the canyon by two different processes, skimming of dense fluid from the top of the dense layer; and by an interfacial mixing flow that mixes fresh fluid down into the dense lower layer (entrainment) while mixing dense fluid into the flow above the canyon (detrainment). A model is developed for the time varying buoyancy profile within the canyon as a function of the Richardson number which parameterizes both the interfacial mixing and skimming processes observed. The continuous release steady-state experiments allowed for the direct measurement of the skimming and interfacial mixing flow rates for any layer depth and Richardson number. Both the skimming rate and the interfacial mixing rate were found to be power-law functions of the Richardson number of the layer. The model results were compared to the results of previously published finite release experiments [Z. Baratian-Ghorghi and N. B. Kaye, Atmos. Environ. 60, 392-402 (2012)], 10.1016/j.atmosenv.2012.06.077. A high degree of consistency was found between the finite release data and the continuous release data. This agreement acts as an excellent check on the measurement techniques used, as the finite release data was based on curve fitting through buoyancy versus time data, while the continuous release data was calculated directly by measuring the rate of addition of volume and buoyancy once a steady-state was established. Finally, a system of ordinary differential equations is presented to model the removal of dense fluid from the canyon based on empirical correlations of the skimming and interfacial mixing taken form the steady-state experiments. The ODE model predicts well the time taken for a finite volume of dense fluid to be flushed from a canyon.

Influence of organic acids on kinetic release of chromium in soil contaminated with leather factory waste in the presence of some adsorbents.

PubMed

Taghipour, Marzieh; Jalali, Mohsen

2016-07-01

In this study, batch experiments were conducted to investigate the effects of nanoparticles (NPs) (MgO, ZnO, TiO2) and clay minerals (bentonite, zeolite) on the release of chromium (Cr) from leather factory waste (LFW) and LFW treated soil using organic acids. Chromium release from all treatments was studied in the presence of citric acid, oxalic acid and CaCl2 solutions. The results showed that, in all treatments, organic acids released more Cr than inorganic salt (CaCl2). The release of Cr by citric acid was higher than that by oxalic acid. In LFW treated soil and LFW, the release of Cr from the all treatments with NPs was less than that from the clay mineral treatments. On the other hand, in the presence of organic acids, Cr release by NPs and clay minerals decreased. Two kinetic models including pseudo-first- and pseudo-second-order model were tested to describe the time dependent Cr release data. Among the kinetic models used, the pseudo-second-order model generally gave the best fits to experimental data. Before and after release experiments, Cr in LFW, treated LFW, control soil and LFW treated soils were fractionated. In all treatments, the greatest amounts of Cr were found in the residual fraction (RES). The organic acids were effective in reducing the exchangeable (EXC), bound to organic matter (OM) and bound to carbonate (CAR) fractions of Cr in all treatments, whereas, after release of Cr from treated soils, Cr remained mainly in the RES fraction. The application of NPs and clay minerals in soil led to a significant transformation of Cr from mobile fractions to the RES fraction. Therefore, organic ligands played a dominant role in mobility and bioavailability of Cr and the removal of Cr by adsorbents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Environmental and Water Quality Operational Studies. Handbook on Reservoir Releases for Fisheries and Environmental Quality.

DTIC Science & Technology

1986-07-01

sluiceway and into the tailwater. In some instances, fish from the reservoir may dominate the fish community in the immediate tailwater. From a fishery ...TITLE (and Su.btitle) S. TYPE OF REPORT & PERIOD COVERED HANDBOOK ON RESERVOIR RELEASES FOR FISHERIES AND Final report ENV IRONMENTAL QUALITY 6...Releases for Fisheries and Environmental Quality," Instruction Report E-86-3, US Army Engineer Waterways Experiment Station, Vicksburg, Miss. 4.S ,k -i

Stress release structures for actuator beams with a stress gradient

NASA Astrophysics Data System (ADS)

Klaasse, G.; Puers, R.; Tilmans, H. A. C.

2007-10-01

Stress release structures are introduced in fixed-fixed beams or membranes for releasing average stress. The influence of a stress gradient on the initial deformation of a fixed-fixed beam with stress release structures is studied in this paper. The objective is to obtain actuator beams that are insensitive to both the average stress and the stress gradient. The target application for the actuator beam in this study is a surface micromachined variable capacitor with a fixed electrode at the center of the beam. An analytical one-dimensional model is derived which predicts the initial deflection of a fixed-fixed beam with one stress release structure at any location and with two stress release structures, placed symmetrically with respect to the center of the beam at any location. The initial center deflection of the beam with one stress release structure was found from the analytical modeling to be zero for a specific set of parameters, but a negative deflection is always present for this specific configuration, leading to beams that touch the substrate at undesired positions, which implies non-functional devices. The configuration with the two symmetrically placed stress release structures can have zero initial center deflection, according to the analytical model, when the stress release structures are placed at a distance of a quarter of the beam length from the anchor points. Finite-element simulations are performed for both configurations and validate the theory. Deviations from the assumed model result in small initial center deflections, but can be compensated for by a little shift of the stress release structures. Experiments are performed for less ideal configurations with two stress release structures where they are shaped as round meanders. These structures do not fully release the stress and the center deflection therefore depends on the average stress to some extent, as demonstrated by finite element simulations. However, the location can be chosen such that there is an initial center deflection that is close to zero. These experiments are, therefore, in qualitative agreement with the analytical model.

Registration of 'Dan' winter hulless barley

USDA-ARS?s Scientific Manuscript database

Dan’ (Reg. No. CV- , PI 659066) six-rowed winter hulless barley (Hordeum vulgare L.) was developed and released by the Virginia Agricultural Experiment Station in March 2009. Dan was derived from the cross VA96-41-17 / SC872143. It was released for production in the eastern United States, as a poten...

Unraveling complexities of velocity dependent retention and release parameters for E. coli in saturated porous media

USDA-ARS?s Scientific Manuscript database

Escherichia coli transport and release experiments were conducted to investigate the pore-water velocity (v) dependency of the sticking efficiency (a), the fraction of the solid surface area that contributed to retention (Sf), the percentage of injected cells that were irreversibly retained (Mirr), ...

Semantic Encoding in Children: A New Method of Investigation.

ERIC Educational Resources Information Center

Kraut, Alan G.; Smothergill, Daniel W.

A familiarization procedure was used in two experiments investigating word encoding in second and sixth graders. Previous studies using release from proactive inhibition had indicated that developmental changes on some encoding dimensions occur during this period. It is argued that the dependence of release from proactive inhibition on deliberate…

Joint release rate estimation and measurement-by-measurement model correction for atmospheric radionuclide emission in nuclear accidents: An application to wind tunnel experiments.

PubMed

Li, Xinpeng; Li, Hong; Liu, Yun; Xiong, Wei; Fang, Sheng

2018-03-05

The release rate of atmospheric radionuclide emissions is a critical factor in the emergency response to nuclear accidents. However, there are unavoidable biases in radionuclide transport models, leading to inaccurate estimates. In this study, a method that simultaneously corrects these biases and estimates the release rate is developed. Our approach provides a more complete measurement-by-measurement correction of the biases with a coefficient matrix that considers both deterministic and stochastic deviations. This matrix and the release rate are jointly solved by the alternating minimization algorithm. The proposed method is generic because it does not rely on specific features of transport models or scenarios. It is validated against wind tunnel experiments that simulate accidental releases in a heterogonous and densely built nuclear power plant site. The sensitivities to the position, number, and quality of measurements and extendibility of the method are also investigated. The results demonstrate that this method effectively corrects the model biases, and therefore outperforms Tikhonov's method in both release rate estimation and model prediction. The proposed approach is robust to uncertainties and extendible with various center estimators, thus providing a flexible framework for robust source inversion in real accidents, even if large uncertainties exist in multiple factors. Copyright © 2017 Elsevier B.V. All rights reserved.

Perfluorocarbon Tracer Experiments on a 2 km Scale in Manchester Showing Ingress of Pollutants into a Building

NASA Astrophysics Data System (ADS)

Matthews, James; Wright, Matthew; Bacak, Asan; Silva, Hugo; Priestley, Michael; Martin, Damien; Percival, Carl; Shallcross, Dudley

2016-04-01

Cyclic perfluorocarbons (PFCs) have been used to measure the passage of air in urban and rural settings as they are chemically inert, non-toxic and have low background concentrations. The use of pre-concentrators and chemical ionisation gas chromatography enables concentrations of a few parts per quadrillion (ppq) to be measured in bag samples. Three PFC tracers were used in Manchester, UK in the summer of 2015 to map airflow in the city and ingress into buildings: perfluomethylcyclohexane (PMCH), perfluoro-2-4-dimethylcyclohexane (mPDMCH) and perfluoro-2-methyl-3-ethylpentene (PMEP). A known quantity of each PFC was released for 15 minutes from steel canisters using pre-prepared PFC mixtures. Release points were chosen to be upwind of the central sampling location (Simon Building, University of Manchester) and varied in distance up to 2.2 km. Six releases using one or three tracers in different configurations and under different conditions were undertaken in the summer. Three further experiments were conducted in the Autumn, to more closely investigate the rate of ingress and decay of tracer indoors. In each experiment, 10 litre samples were made over 30 minutes into Tedlar bags, starting at the same time the as PFC release. Samples were taken in 11 locations chosen from 15 identified areas including three in public parks, three outside within the University of Manchester area, seven inside and five outside of the Simon building and two outside a building nearby. For building measurements, receptors were placed inside the buildings on different floors; outside measurements were achieved through a sample line out of the window. Three of the sample positions inside the Simon building were paired with samplers outside to allow indoor-outdoor comparisons. PFC concentrations varied depending on location and height. The highest measured concentrations occurred when the tracer was released at sunrise; up to 330 ppq above background (11 ppq) of PMCH was measured at the 6th floor of the Simon Building from a release 1.9 km away. One experiment sampled for an additional two 30 minute periods in four locations inside and one location outside the Simon Building in order to investigate how long it took for air to enter and leave the building. For this measurement, 1.3 g of PMCH was released 1.9 km away and average roof level wind speed was 7.8 m/s. The highest measurement of PMCH outside was 54 ppq above background, and 46 ppq inside. After the first 30 minutes, the PFC concentration returned to background levels outside, but other internal rooms still had elevated PFC concentrations between 10 and 16 ppq above background an hour after release demonstrating that pollutants may persist within buildings having passed outside. In the final experiment, the wind direction changed so the sampling locations were not directly downwind of the release point, but nevertheless a small amount of PFC tracer above background was detected at the highest sampling point on the 6th floor of the Simon Building (14 ppq above background), and a smaller amount at street level.

Corticotropin-releasing factor accelerates metamorphosis in Bufo arenarum: effect on pituitary ACTH and TSH cells.

PubMed

Miranda, L A; Affanni, J M; Paz, D A

2000-04-01

The actions of several neuropeptides as hypothalamic mediators in the regulation of Bufo arenarum metamorphosis were investigated. Prometamorphic larvae were injected with 1.5 microg thyrotropin-releasing hormone (TRH), 2 microg ovine corticotropin-releasing factor (oCRF), 2 microg mammalian gonadotropin-releasing hormone (mGnRH), 2 microg human growth hormone-releasing hormone (hGHRH), or Holtfreter solution (control group). Larvae received two injections with the same dose: one at the beginning of the experiment and the other 7 days later. Several morphologic parameters (total length, tail length, wet weight, hind limb length, and metamorphic stages) were measured as indicators of growth and metamorphic development. These measurements were taken in 20 larvae per treatment or control group at the beginning of the experiment, at day 7 and at day 14 when the experiment ended. We observed that only the administration of exogenous CRF stimulated resorption of the tail and accelerated the rate of metamorphosis. In the pituitary of CRF-treated larvae we observed that thyrotropin (TSH) and adrenocorticotropic hormone (ACTH) producing cells showed a weaker immunoreactivity, a decrease in cell number and a reduction of volume density when compared with normal larvae. In conclusion, the results obtained indicate a possible role for CRF in Bufo arenarum metamorphosis. CRF may regulate interrenal and thyroid activity by acting directly upon TSH and ACTH cells. On the other hand, TRH, GnRH and GHRH were inactive in stimulating growth or metamorphosis of Bufo arenarum. J. Exp. Zool. 286:473-480, 2000. Copyright 2000 Wiley-Liss, Inc.

The influence of DOM and microbial processes on arsenic release from karst during ASR operations in the Floridan Aquifer

NASA Astrophysics Data System (ADS)

Jin, J.; Zimmerman, A. R.

2011-12-01

The mobilization of subsurface As poses a serious threat to human health, particularly in a region such as Florida where population is heavily dependent on highly porous karstic aquifers for drinking water. Injection water used in aquifer storage and recovery (ASR) or aquifer recharge (AR) operations is commonly high in dissolved organic matter (DOM) and OM can also be present in the subsurface carbonate rock. Using batch incubation experiments, this study examined the role of core preservation methods, as well as the influence of labile and more refractory DOM on the mobilization of As from carbonate rock. Incubation experiments used sealed reaction vessels with preserved and homogenized core materials collected via coring the Suwannee Formation in southwest Florida and treatment additions consisting of 1) source water (SW) enriched in sterilized soil DOM, 2) SW enriched in soil DOM and microbes, and 3) SW enriched in sodium acetate. During an initial equilibration phase in native groundwater (NGW) with low dissolved oxygen (DO; Phase 1), we found the greatest As release of the whole incubation. In the beginning of Phase 2 (N2 headspace) in which NGW was replaced with treatment solutions, there was little As release except in the vessel with Na-acetate added, which also had the lowest ORP. At the start of Phase 3, when incubations were exposed to air, most vessels saw more ion (including As) release into solution. Vessel with Na-acetate had less As release in Phase 3 than in Phase 2. During all experimental phases, treatments of DOM or microbe additions had no apparent effect on the amount of As release. The core materials was found contain significant amount of indigenous DOM (about 8 g OC/kg core) which was released during the incubation so DOC concentrations displayed no clear pattern among different treatments. At least three abiotic As mobilization mechanisms may play a role in As released during different stages of the experiment. Desorption of As from iron oxyhydroxides may have occurred, particularly at the beginning of each experimental phase. Reductive dissolution and oxidative dissolution likely lead to As release during phase 2 and 3, respectively. While not directly implicated, the presence of labile OM clearly fueled microbial alteration of redox conditions, leading to further As release. Addition of microbes had no effect as indigenous microbes were just as active in untreated cores.

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the Extended Baryon Oscillation Spectroscopic Survey and from the Second Phase of the Apache Point Observatory Galactic Evolution Experiment

NASA Astrophysics Data System (ADS)

Abolfathi, Bela; Aguado, D. S.; Aguilar, Gabriela; Allende Prieto, Carlos; Almeida, Andres; Tasnim Ananna, Tonima; Anders, Friedrich; Anderson, Scott F.; Andrews, Brett H.; Anguiano, Borja; Aragón-Salamanca, Alfonso; Argudo-Fernández, Maria; Armengaud, Eric; Ata, Metin; Aubourg, Eric; Avila-Reese, Vladimir; Badenes, Carles; Bailey, Stephen; Balland, Christophe; Barger, Kathleen A.; Barrera-Ballesteros, Jorge; Bartosz, Curtis; Bastien, Fabienne; Bates, Dominic; Baumgarten, Falk; Bautista, Julian; Beaton, Rachael; Beers, Timothy C.; Belfiore, Francesco; Bender, Chad F.; Bernardi, Mariangela; Bershady, Matthew A.; Beutler, Florian; Bird, Jonathan C.; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael R.; Blomqvist, Michael; Bolton, Adam S.; Boquien, Médéric; Borissova, Jura; Bovy, Jo; Andres Bradna Diaz, Christian; Nielsen Brandt, William; Brinkmann, Jonathan; Brownstein, Joel R.; Bundy, Kevin; Burgasser, Adam J.; Burtin, Etienne; Busca, Nicolás G.; Cañas, Caleb I.; Cano-Díaz, Mariana; Cappellari, Michele; Carrera, Ricardo; Casey, Andrew R.; Cervantes Sodi, Bernardo; Chen, Yanping; Cherinka, Brian; Chiappini, Cristina; Doohyun Choi, Peter; Chojnowski, Drew; Chuang, Chia-Hsun; Chung, Haeun; Clerc, Nicolas; Cohen, Roger E.; Comerford, Julia M.; Comparat, Johan; Correa do Nascimento, Janaina; da Costa, Luiz; Cousinou, Marie-Claude; Covey, Kevin; Crane, Jeffrey D.; Cruz-Gonzalez, Irene; Cunha, Katia; da Silva Ilha, Gabriele; Damke, Guillermo J.; Darling, Jeremy; Davidson, James W., Jr.; Dawson, Kyle; de Icaza Lizaola, Miguel Angel C.; de la Macorra, Axel; de la Torre, Sylvain; De Lee, Nathan; de Sainte Agathe, Victoria; Deconto Machado, Alice; Dell’Agli, Flavia; Delubac, Timothée; Diamond-Stanic, Aleksandar M.; Donor, John; José Downes, Juan; Drory, Niv; du Mas des Bourboux, Hélion; Duckworth, Christopher J.; Dwelly, Tom; Dyer, Jamie; Ebelke, Garrett; Davis Eigenbrot, Arthur; Eisenstein, Daniel J.; Elsworth, Yvonne P.; Emsellem, Eric; Eracleous, Michael; Erfanianfar, Ghazaleh; Escoffier, Stephanie; Fan, Xiaohui; Fernández Alvar, Emma; Fernandez-Trincado, J. G.; Cirolini, Rafael Fernando; Feuillet, Diane; Finoguenov, Alexis; Fleming, Scott W.; Font-Ribera, Andreu; Freischlad, Gordon; Frinchaboy, Peter; Fu, Hai; Gómez Maqueo Chew, Yilen; Galbany, Lluís; García Pérez, Ana E.; Garcia-Dias, R.; García-Hernández, D. A.; Garma Oehmichen, Luis Alberto; Gaulme, Patrick; Gelfand, Joseph; Gil-Marín, Héctor; Gillespie, Bruce A.; Goddard, Daniel; González Hernández, Jonay I.; Gonzalez-Perez, Violeta; Grabowski, Kathleen; Green, Paul J.; Grier, Catherine J.; Gueguen, Alain; Guo, Hong; Guy, Julien; Hagen, Alex; Hall, Patrick; Harding, Paul; Hasselquist, Sten; Hawley, Suzanne; Hayes, Christian R.; Hearty, Fred; Hekker, Saskia; Hernandez, Jesus; Hernandez Toledo, Hector; Hogg, David W.; Holley-Bockelmann, Kelly; Holtzman, Jon A.; Hou, Jiamin; Hsieh, Bau-Ching; Hunt, Jason A. S.; Hutchinson, Timothy A.; Hwang, Ho Seong; Jimenez Angel, Camilo Eduardo; Johnson, Jennifer A.; Jones, Amy; Jönsson, Henrik; Jullo, Eric; Sakil Khan, Fahim; Kinemuchi, Karen; Kirkby, David; Kirkpatrick, Charles C., IV; Kitaura, Francisco-Shu; Knapp, Gillian R.; Kneib, Jean-Paul; Kollmeier, Juna A.; Lacerna, Ivan; Lane, Richard R.; Lang, Dustin; Law, David R.; Le Goff, Jean-Marc; Lee, Young-Bae; Li, Hongyu; Li, Cheng; Lian, Jianhui; Liang, Yu; Lima, Marcos; Lin, Lihwai; Long, Dan; Lucatello, Sara; Lundgren, Britt; Mackereth, J. Ted; MacLeod, Chelsea L.; Mahadevan, Suvrath; Geimba Maia, Marcio Antonio; Majewski, Steven; Manchado, Arturo; Maraston, Claudia; Mariappan, Vivek; Marques-Chaves, Rui; Masseron, Thomas; Masters, Karen L.; McDermid, Richard M.; McGreer, Ian D.; Melendez, Matthew; Meneses-Goytia, Sofia; Merloni, Andrea; Merrifield, Michael R.; Meszaros, Szabolcs; Meza, Andres; Minchev, Ivan; Minniti, Dante; Mueller, Eva-Maria; Muller-Sanchez, Francisco; Muna, Demitri; Muñoz, Ricardo R.; Myers, Adam D.; Nair, Preethi; Nandra, Kirpal; Ness, Melissa; Newman, Jeffrey A.; Nichol, Robert C.; Nidever, David L.; Nitschelm, Christian; Noterdaeme, Pasquier; O’Connell, Julia; Oelkers, Ryan James; Oravetz, Audrey; Oravetz, Daniel; Aquino Ortíz, Erik; Osorio, Yeisson; Pace, Zach; Padilla, Nelson; Palanque-Delabrouille, Nathalie; Alonso Palicio, Pedro; Pan, Hsi-An; Pan, Kaike; Parikh, Taniya; Pâris, Isabelle; Park, Changbom; Peirani, Sebastien; Pellejero-Ibanez, Marcos; Penny, Samantha; Percival, Will J.; Perez-Fournon, Ismael; Petitjean, Patrick; Pieri, Matthew M.; Pinsonneault, Marc; Pisani, Alice; Prada, Francisco; Prakash, Abhishek; Queiroz, Anna Bárbara de Andrade; Raddick, M. Jordan; Raichoor, Anand; Barboza Rembold, Sandro; Richstein, Hannah; Riffel, Rogemar A.; Riffel, Rogério; Rix, Hans-Walter; Robin, Annie C.; Rodríguez Torres, Sergio; Román-Zúñiga, Carlos; Ross, Ashley J.; Rossi, Graziano; Ruan, John; Ruggeri, Rossana; Ruiz, Jose; Salvato, Mara; Sánchez, Ariel G.; Sánchez, Sebastián F.; Sanchez Almeida, Jorge; Sánchez-Gallego, José R.; Santana Rojas, Felipe Antonio; Santiago, Basílio Xavier; Schiavon, Ricardo P.; Schimoia, Jaderson S.; Schlafly, Edward; Schlegel, David; Schneider, Donald P.; Schuster, William J.; Schwope, Axel; Seo, Hee-Jong; Serenelli, Aldo; Shen, Shiyin; Shen, Yue; Shetrone, Matthew; Shull, Michael; Silva Aguirre, Víctor; Simon, Joshua D.; Skrutskie, Mike; Slosar, Anže; Smethurst, Rebecca; Smith, Verne; Sobeck, Jennifer; Somers, Garrett; Souter, Barbara J.; Souto, Diogo; Spindler, Ashley; Stark, David V.; Stassun, Keivan; Steinmetz, Matthias; Stello, Dennis; Storchi-Bergmann, Thaisa; Streblyanska, Alina; Stringfellow, Guy S.; Suárez, Genaro; Sun, Jing; Szigeti, Laszlo; Taghizadeh-Popp, Manuchehr; Talbot, Michael S.; Tang, Baitian; Tao, Charling; Tayar, Jamie; Tembe, Mita; Teske, Johanna; Thakar, Aniruddha R.; Thomas, Daniel; Tissera, Patricia; Tojeiro, Rita; Tremonti, Christy; Troup, Nicholas W.; Urry, Meg; Valenzuela, O.; van den Bosch, Remco; Vargas-González, Jaime; Vargas-Magaña, Mariana; Vazquez, Jose Alberto; Villanova, Sandro; Vogt, Nicole; Wake, David; Wang, Yuting; Weaver, Benjamin Alan; Weijmans, Anne-Marie; Weinberg, David H.; Westfall, Kyle B.; Whelan, David G.; Wilcots, Eric; Wild, Vivienne; Williams, Rob A.; Wilson, John; Wood-Vasey, W. M.; Wylezalek, Dominika; Xiao, Ting; Yan, Renbin; Yang, Meng; Ybarra, Jason E.; Yèche, Christophe; Zakamska, Nadia; Zamora, Olga; Zarrouk, Pauline; Zasowski, Gail; Zhang, Kai; Zhao, Cheng; Zhao, Gong-Bo; Zheng, Zheng; Zheng, Zheng; Zhou, Zhi-Min; Zhu, Guangtun; Zinn, Joel C.; Zou, Hu

2018-04-01

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes the second data release from this phase, and the 14th from SDSS overall (making this Data Release Fourteen or DR14). This release makes the data taken by SDSS-IV in its first two years of operation (2014–2016 July) public. Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey; the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data-driven machine-learning algorithm known as “The Cannon” and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from the SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS web site (www.sdss.org) has been updated for this release and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020 and will be followed by SDSS-V.

The Numerical Simulation of a Tracer-Release Field Project to Study Motion within the Nocturnal Boundary Layer

NASA Astrophysics Data System (ADS)

Werth, D. W.; Leclerc, M. Y.; Buckley, R.; Parker, M.; Kurzeja, R.; Duarte, H. F.; Zhang, G.; Durden, D.

2009-12-01

The Savannah River National Laboratory (SRNL), Brookhaven National Laboratory (BNL), the University of Georgia (UGA), and the National Oceanic and Atmospheric Administration (NOAA) conducted a regional tracer experiment to study the nocturnal behavior of CO2 in the vicinity of an instrumented tall tower during two nights on May 11th and 12th, 2009. The experiment consisted of a release of five perfluorocarbon tracer (PFTs) compounds in twelve unique locations in Aiken County, South Carolina. Intensive meteorological measurements including in-situ turbulence were made in conjunction with the release and sampling of the PFTs. A 300m tower was also used to collect data from higher levels, allowing us to determine the extent to which the tracer was mixed vertically. Lagrangian plume simulations performed during the experiment demonstrated transport over distances of >8 km, and correlated well with in situ sampling. The area was characterized by heavy vegetation cover, and carbon dioxide concentrations were also monitored in an effort to determine how respiration and advection affect CO2 levels in the stable layer. Tracer release locations were carefully selected via a fine-scale mesoscale modeling study of similar nights. The purpose of these experiments was to provide data that will be used to increase the understanding of the terrestrial carbon budget, especially with respect to nocturnal boundary layer (NBL) phenomena such as low level jets and breaking gravity waves. Using these data, a simulation of the motion of the tracer within the boundary layer was developed using the Regional Atmospheric Modeling System (RAMS) mesoscale model coupled to a tracer model. The RAMS model was also coupled to the Simple Biosphere (SiB) vegetation model, which allowed for the simulation of the release of carbon dioxide into the NBL. The simulation results are used to validate the NBL hypothesis of CO2 monitoring, by which the release of CO2 can be correlated with the accumulation of CO2 in the boundary layer beneath a stable ‘lid’, which impedes vertical mixing. This is done with both the tracer, in which the release rate is known and no advection occurs, and for CO2, in which the release rate is not known and for which advection of CO2 must be accounted. The high resolution of the simulation allows us to resolve the small-scale motions within the NBL, which are important to nocturnal transport. Flux data from the tall tower were studied to learn more about the eddy transport, and also to detect the occurrence of transport ‘events’ in which the CO2 and H2O values experience a sudden increase. A wavelet analysis is also applied, and reveals the existence of eddy activity dominated by eddies of diameter 90-240m.

Modeling of HT and HTO release from irradiated lithium metazirconate

NASA Astrophysics Data System (ADS)

Beloglazov, S.; Nishikawa, M.; Glugla, M.; Kinjyo, T.

2004-08-01

Modeling studies of tritium release from irradiated Li 2ZrO 3 (MAPI) pebbles have been carried out in order to evaluate the effect of purge gas composition on tritium release behavior. The release characteristics were obtained by temperature programmed desorption (TPD) technique in the series of post-irradiation experiments in JRR-4 research reactor of JAERI. Nitrogen with hydrogen at various partial pressures (100 and 1000 Pa) was used as a purge gas. Two sets of ionization chambers and its dedicated electrometers allowed the tritium concentration to be monitored in the chemical form of HT and overall tritium concentration in the mixture HT and HTO simultaneously during desorption runs. The tritium release curves were numerically fitted in order to evaluate the mass transfer coefficients.

Diadenosine polyphosphates release by human corneal epithelium.

PubMed

Carracedo, Gonzalo; Guzman-Aranguez, Ana; Loma, Patricia; Pintor, Jesús

2013-08-01

Diadenosine polyphosphates are a type of dinucleotides that have been detected in rabbit and human tears. However, their origin and their mechanism of release have not been fully elucidated. In this work we investigated whether the dinucleotides Ap4A and Ap5A can be released from human corneal epithelia as a consequence of shear stress stimuli. In in vitro experiments, concentrations of Ap4A and Ap5A before mechanical stimulus of stratified human corneal epithelial cells were 3.18 ± 0.43 nM and 0.81 ± 0.13 nM, respectively. After shear stimulation, concentrations significantly increased to 12.01 ± 2.19 nM for Ap4A and 2.83 ± 0.41 nM for Ap5A. No significant differences in lactate dehydrogenase activity were detected between non-stimulated stratified human corneal epithelial cells and cells exposed to mechanical shear-stress, indicating that the rise of dinucleotide levels was not due to cell lysis. In in vivo experiments, individuals subjected to a rise in blinking frequency showed a significant increase of Ap4A (∼25-fold when experiment was performed without anaesthetic and 75-fold with anaesthetic) and Ap5A concentration in tears (∼50-fold when experiment was performed without anaesthetic and 125-fold with anaesthetic). Shear-stress stimuli induces Ap4A and Ap5A release from human corneal epithelium, thus explaining the origin of these relevant compounds for the ocular surface biochemistry and physiology. Copyright © 2013 Elsevier Ltd. All rights reserved.

Emotional maltreatment is associated with atypical responding to stimulation of endogenous oxytocin release through mechanically-delivered massage in males.

PubMed

Riem, Madelon M E; De Carli, Pietro; van IJzendoorn, Marinus H; Linting, Marielle; Grewen, Karen M; Bakermans-Kranenburg, Marian J

2017-11-01

The neuropeptide oxytocin plays an important role in social behavior, parenting, and affectionate touch and there is some evidence that oxytocin release can be stimulated by massage or affectionate touch. We examined the effects of massage applied by a massage seat cover on salivary oxytocin levels in two exploratory studies using within-subject designs. In Study 1 massage effects on oxytocin levels were examined in a sample of N=20 healthy female participants. Effects of a 15-min massage session were compared to a control condition during which participants sat on a comfortable chair without a massage seat cover. Salivary oxytocin levels were measured at baseline and up to three hours after the session. We found that massage attenuated oxytocin decreases over time, indicating that massage stimulates oxytocin release. In Study 2, we examined whether effects of massage in N=46 healthy male participants depend on experiences of emotional maltreatment. In addition, we examined whether enhanced oxytocin levels after massage affect the use of excessive handgrip force in response to infant crying and laughter as measured with a handgrip dynamometer. Our findings show that massage results in elevated oxytocin levels compared to a control condition, but that the effects of massage are dependent on experiences of emotional maltreatment. Men with experiences of emotional maltreatment showed lower oxytocin levels, which did not increase after massage. Furthermore, we found that high oxytocin levels after massage were related to reduced handgrip force during exposure to infant crying and laughter, indicating that massage stimulates a sensitive response to infant signals by stimulating oxytocin release. Although massage did not affect oxytocin levels in individuals with experiences of maltreatment, it reduced the use of handgrip force in response to infant crying and laughter in these individuals. Our findings indicate that emotional maltreatment is associated with atypical responding to stimulation of endogenous oxytocin release. Copyright © 2017 Elsevier Ltd. All rights reserved.

Increased seedling establishment via enemy release at the upper elevational range limit of sugar maple.

PubMed

Urli, Morgane; Brown, Carissa D; Narváez Perez, Rosela; Chagnon, Pierre-Luc; Vellend, Mark

2016-11-01

The enemy release hypothesis is frequently invoked to explain invasion by nonnative species, but studies focusing on the influence of enemies on natural plant range expansion due to climate change remain scarce. We combined multiple approaches to study the influence of plant-enemy interactions on the upper elevational range limit of sugar maple (Acer saccharum) in southeastern Québec, Canada, where a previous study had demonstrated intense seed predation just beyond the range limit. Consistent with the hypothesis of release from natural enemies at the range limit, data from both natural patterns of regeneration and from seed and seedling transplant experiments showed higher seedling densities at the range edge than in the core of the species' distribution. A growth chamber experiment manipulating soil origin and temperature indicated that this so-called "happy edge" was not likely caused by temperature (i.e., the possibility that climate warming has made high elevation temperatures optimal for sugar maple) or by abiotic soil factors that vary along the elevational gradient. Finally, an insect-herbivore-exclusion experiment showed that insect herbivory was a major cause of seedling mortality in the core of sugar maple's distribution, whereas seedlings transplanted at or beyond the range edge experienced minimal herbivory (i.e., enemy release). Insect herbivory did not completely explain the high levels of seedling mortality in the core of the species' distribution, suggesting that seedlings at or beyond the range edge may also experience release from pathogens. In sum, while some effects of enemies are magnified beyond range edges (e.g., seed predation), others are dampened at and beyond the range edge (e.g., insect herbivory), such that understanding the net outcome of different biotic interactions within, at and beyond the edge of distribution is critical to predicting species' responses to global change. © 2016 by the Ecological Society of America.

Research on the Characteristics and Mechanism of the Cumulative Release of Antimony from an Antimony Smelting Slag Stacking Area under Rainfall Leaching

PubMed Central

Zhou, Yingying; Deng, Renjian

2017-01-01

We aimed to study the characteristics and the mechanism of the cumulative release of antimony at an antimony smelting slag stacking area in southern China. A series of dynamic and static leaching experiments to simulate the effects of rainfall were carried out. The results showed that the release of antimony from smelting slag increased with a decrease in the solid-liquid ratio, and the maximum accumulated release was found to be 42.13 mg Sb/kg waste and 34.26 mg Sb/kg waste with a solid/liquid ratio of 1 : 20; the maximum amount of antimony was released within 149–420 μm size fraction with 7.09 mg/L of the cumulative leaching. Also, the antimony release was the greatest and most rapid at pH 7.0 with the minimum release found at pH 4.0. With an increase in rainfall duration, the antimony release increased. The influence of variation in rainfall intensity on the release of antimony from smelting slag was small. PMID:28804669

Opioid receptor and β-arrestin2 densities and distribution change after sexual experience in the ventral tegmental area of male rats.

PubMed

Garduño-Gutiérrez, René; León-Olea, Martha; Rodríguez-Manzo, Gabriela

2018-05-15

Sexual experience modifies brain functioning and copulatory efficiency. Sexual activity, ejaculation in particular, is a rewarding behavior associated with the release of endogenous opioids, which modulate the activity of the mesolimbic dopaminergic system (MLS). In sexually exhausted rats, repeated ejaculation produces μ (MOR) and δ opioid receptor (DOR) internalization in ventral tegmental area (VTA) neurons, as well as long-lasting behavioral changes suggestive of brain plasticity processes. We hypothesized that in sexually naïve rats the endogenous opioids released during sexual experience acquisition, might contribute to brain plasticity processes involved in the generation of the behavioral changes induced by sexual experience. To this aim, using double immunohistochemistry and confocal microscopy, we compared in vivo MOR, DOR and β-arrestin2 densities and activation in the VTA of sexually naïve males, sexually experienced rats not executing sexual activity prior to sacrifice and sexually experienced animals that ejaculated once before sacrifice. Results showed that sexual experience acquisition improved male's copulatory ability and induced persistent changes in the density, cellular distribution and activation of MOR and β-arrestin2 in VTA neurons. DOR density was not modified, but its cellular location changed after sexual experience, revealing that these two opioid receptors were differentially activated during sexual experience acquisition. It is concluded that the endogenous opioids released during sexual activity produce adjustments in VTA neurons of sexually naïve male rats that might contribute to the behavioral plasticity expressed as an improvement in male copulatory parameters, promoted by the acquisition of sexual experience. Copyright © 2018 Elsevier Inc. All rights reserved.

Intracellular calcium movements during excitation–contraction coupling in mammalian slow-twitch and fast-twitch muscle fibers

PubMed Central

Hollingworth, Stephen

2012-01-01

In skeletal muscle fibers, action potentials elicit contractions by releasing calcium ions (Ca2+) from the sarcoplasmic reticulum. Experiments on individual mouse muscle fibers micro-injected with a rapidly responding fluorescent Ca2+ indicator dye reveal that the amount of Ca2+ released is three- to fourfold larger in fast-twitch fibers than in slow-twitch fibers, and the proportion of the released Ca2+ that binds to troponin to activate contraction is substantially smaller. PMID:22450485

Building sandbars in the Grand Canyon

USGS Publications Warehouse

Grams, Paul E.; Schmidt, John C.; Wright, Scott A.; Topping, David; Melis, Theodore S.; Rubin, David M.

2015-01-01

Now, by implementing a new strategy that calls for repeated releases of large volumes of water from the dam, the U.S. Department of the Interior (DOI) seeks to increase the size and number of these sandbars. Three years into the "high-flow experiment" (HFE) protocol, the releases appear to be achieving the desired effect. Many sandbars have increased in size following each controlled flood, and the cumulative results of the first three releases suggest that sandbar declines may be reversed if controlled floods can be implemented frequently enough.

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

Experiments on the high-temperature behaviour of neutron-irradiated uranium dioxide and fission products, volume 8, number 1

NASA Astrophysics Data System (ADS)

Tanke, R. H. J.

The release rate of fission products from overheated UO2, the chemical form of these fission products, and the transport mechanism inside the nuclear fuel are determined. UO spheres of approximately 1 mm diameter, irradiated in a high-flux reactor were used for the experiments. The chemical forms of the particles released from the spheres during evaporation were determined by mass spectrometry and the release rate of the mission products was determined by gamma spectrometry. A gamma topographer was developed to determine the change with temperature in the three dimensional distribution of radioactive fission products in the spheres. No clear relationship between the stoichiometry of the spheres and uranium consumption were shown. A diffusion model was used to determine the activation energy for the diffusion of fission products. It is concluded that the microstructure of the nuclear fuel greatly affects the number of free oxygen atoms, the release rate and the chemical form of the fission products. The evaporation of the UO2 matrix is the main mechanism for the release of all fission products at temperatures above 2300 K. Barium can be as volatile as iodine. Niobium and lanthenum can be volatile. Molecular combinations of the fission products, iodine, cesium and tellurium, are highly unlikely to be present inside the fuel. Barium and nobium may form compounds with oxygen and are then released as simple oxides. Fission products are released from overheated UO2 or as oxides. A new model is proposed for describing the behavior of oxygen in irradiated nuclear fuel.

Phosphorus release from ash and remaining tissues of two wetland species after a prescribed fire.

PubMed

Liu, G D; Gu, B; Miao, S L; Li, Y C; Migliaccio, K W; Qian, Y

2010-01-01

Dead plant tissues and ash from a prescribed fire play an important role in nutrient balance and cycling in the Florida Everglades ecosystem. The objective of this study was to assess the dynamic changes in total phosphorus release (TPr) from ash or tissues of either cattail (Typha domingensis Pers.) or sawgrass (Cladium jamaicense Crantz) to water. Natural-dead (senesced-dead) and burning-dead (standing-dead due to a prescribed fire) cattail and sawgrass were collected from highly (H) and moderately (M) impacted zones in the Florida Everglades. This experiment was conducted by incubation and water-extraction of the materials in plastic bottles for 65 d at room temperature (24 +/- 1 degrees C). Results showed that 63 to 88%, 17 to 48%, 9 to 20%, and 13 to 28% of total P (TPp) were released as TPr from cattail and sawgrass ash, cattail tissues from the H zone, cattail tissues, and sawgrass tissues from the M zone, respectively. TPp means total P of plant tissues, whereas TPr is total P release from the tissues or ash. Most of the TPr was released within 24 h after burning. The quick release of TPr observed in this experiment may help explain the P surge in the surface water immediately following a fire in the marsh. These findings suggest that prescribed burning accelerates P release from cattail and sawgrass. They also imply that it is very important to keep the water stagnant in the first 24 h to maximize the benefits of a prescribed fire in the Everglades.

On the spreading and instability of gravity current fronts of arbitrary shape

NASA Astrophysics Data System (ADS)

Zgheib, N.; Bonometti, T.; Balachandar, S.

2012-11-01

Experiments, simulations and theoretical analysis were carried out to study the influence of geometry on the spreading of gravity currents. The horizontal spreading of three different intial planforms of initial release were investigated: an extended ellipse, a cross, and a circle. The experiments used a pulley system for a swift nearly instantaneous release. The case of the axisymmetric cylinder compared favorably with earlier simulations. We ran experiments for multiple aspect ratios for all three configurations. Perhaps the most intriguing of the three cases is the ``ellipse,'' which within a short period of release flipped the major and minor axes. This behavior cannot be captured by current theoretical methods (such as the Box Model). These cases have also been investigated using shallow water and direct numerical simulations. Also, in this study, we investigate the possibility of a Rayleigh-Taylor (RT) instability of the radially moving, but decelerating front. We present a simple theoretical framework based on the inviscid Shallow Water Equations. The theoretical results are supplemented and compared to highly resolved three-dimensional simulations with the Boussinesq approximation. Chateaubriand Fellowship - NSF PIRE grant OISE-0968313.

Evaluation of a mark-recapture method for estimating mortality and migration rates of stratified populations

USGS Publications Warehouse

Dorazio, R.M.; Rago, P.J.

1991-01-01

We simulated mark–recapture experiments to evaluate a method for estimating fishing mortality and migration rates of populations stratified at release and recovery. When fish released in two or more strata were recovered from different recapture strata in nearly the same proportions, conditional recapture probabilities were estimated outside the [0, 1] interval. The maximum likelihood estimates tended to be biased and imprecise when the patterns of recaptures produced extremely "flat" likelihood surfaces. Absence of bias was not guaranteed, however, in experiments where recapture rates could be estimated within the [0, 1] interval. Inadequate numbers of tag releases and recoveries also produced biased estimates, although the bias was easily detected by the high sampling variability of the estimates. A stratified tag–recapture experiment with sockeye salmon (Oncorhynchus nerka) was used to demonstrate procedures for analyzing data that produce biased estimates of recapture probabilities. An estimator was derived to examine the sensitivity of recapture rate estimates to assumed differences in natural and tagging mortality, tag loss, and incomplete reporting of tag recoveries.

Space fireworks for upper atmospheric wind measurements by sounding rocket experiments

NASA Astrophysics Data System (ADS)

Yamamoto, M.

2016-01-01

Artificial meteor trains generated by chemical releases by using sounding rockets flown in upper atmosphere were successfully observed by multiple sites on ground and from an aircraft. We have started the rocket experiment campaign since 2007 and call it "Space fireworks" as it illuminates resonance scattering light from the released gas under sunlit/moonlit condition. By using this method, we have acquired a new technique to derive upper atmospheric wind profiles in twilight condition as well as in moonlit night and even in daytime. Magnificent artificial meteor train images with the surrounding physics and dynamics in the upper atmosphere where the meteors usually appear will be introduced by using fruitful results by the "Space firework" sounding rocket experiments in this decade.

Informal Helping Mechanisms: Conceptual Issues in Family Support of Reentry of Former Prisoners

ERIC Educational Resources Information Center

Martinez, Damian J.

2006-01-01

Reentry of formerly incarcerated individuals into society is an experience that must be negotiated not only by the former prisoner, but also by many other actors. Research has examined the pre-prison experiences, the incarceration experiences, and the post-release behavior of former prisoners, focusing on how such experiences affect the…

Systematic Errors in an Air Track Experiment.

ERIC Educational Resources Information Center

Ramirez, Santos A.; Ham, Joe S.

1990-01-01

Errors found in a common physics experiment to measure acceleration resulting from gravity using a linear air track are investigated. Glider position at release and initial velocity are shown to be sources of systematic error. (CW)

Release of Escherichia coli under raindrop impact: The role of clay

NASA Astrophysics Data System (ADS)

Wang, C.; Parlange, J.-Y.; Schneider, R. L.; Rasmussen, E. W.; Wang, X.; Chen, M.; Dahlke, H. E.; Truhlar, A. M.; Walter, M. T.

2018-01-01

A recent paper by Wang et al. (2017) showed that the release of Escherichia coli (E. coli) from soil into overland flow under raindrop impact and the release of clay follow identical temporal patterns. This raised the question: what is the role of clay, if any, in E. coli transfer from soil to overland flow, e.g., does clay facilitate E. coli transfer? Using simulated rainfall experiments over soil columns with and without clay in the matrix, we found there was significantly more E. coli released from the non-clay soil because raindrops penetrated more deeply than into the soil with clay.

Hydrophobic interaction mediated coating of Pluronics on mesoporous silica nanoparticle with stimuli responsiveness for cancer therapy.

PubMed

Sha, Luping; Wang, Da; Mao, Yuling; Shi, Wei; Gao, Tianbin; Zhao, Qinfu; Wang, Si-Ling

2018-05-22

In this research, a novel method was used to successfully make Pluronic P123 stably coated on mesoporous silica nanoparticles (MSN). That P123 and MSN co-constructed a drug delivery system (DDS) had not been reported. In this DDS, the coating of P123 was realized through hydrophobic interaction with octadecyl chain modified MSN. Experiments found only Pluronic with an appropriate ratio of hydrophilic and lipophilic segment could keep the nanoassemblies stable. For comparison, nanoassemblies consisted of P123 and octadecyl chain modified MSN with or without disulfide bond were prepared, which were denoted as PSMSN and PMSN respectively. Disulfide bond was expected to endow the system with redox-responsiveness to enhance the therapeutic effect meanwhile decrease toxicity. A series of experiments including characterization of the nanoparticles, in vitro drug release, cell uptake and cellular drug release, in vitro cytotoxicity, cell migration and biodistribution of the nanoparticles were carried out. Compared with PMSN, PSMSN displayed redox-responsive drug release property not only in in vitro release text, but also on the cellular level. In addition, cell migration experiments proved that the coating of P123 endowed the system with the ability of anti-metastasis. The accumulation of P123 in tumor was enhanced after coating on MSN by virtue of the "EPR" effect of nanoparticles compared with the solution form. . © 2018 IOP Publishing Ltd.

Registration of ‘Ok101’ Wheat

USDA-ARS?s Scientific Manuscript database

‘Ok101’ (Reg. no. CV-932, PI 631493) is a hard red winter wheat (Triticum aestivum L.) developed cooperatively by the Oklahoma Agricultural Experiment Station and the USDA-ARS, and released in March 2001. Ok101 was released for its high tolerance to acidic soil, broad adaptation to both dual-purpose...

Applying Learning Analytics to Investigate Timed Release in Online Learning

ERIC Educational Resources Information Center

Martin, Florence; Whitmer, John C.

2016-01-01

Adaptive learning gives learners control of context, pace, and scope of their learning experience. This strategy can be implemented in online learning by using the "Adaptive Release" feature in learning management systems. The purpose of this study was to use learning analytics research methods to explore the extent to which the adaptive…

76 FR 77281 - Self-Regulatory Organizations; The Depository Trust Company; Notice of Filing and Immediate...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-12

... SECURITIES AND EXCHANGE COMMISSION [Release No. 34-65901; File No. SR-DTC-2011-10] Self-Regulatory... DTC participants. DTC's experience demonstrates that when participants, issuers, underwriters, agents... Exchange Act Release 24818 (August 19, 1987), 52 FR 31833 (August 24, 1987) (File No. SR-DTC-87-10); 25948...

Dynamics of an Unsteady Diffusion Flame: Effects of Heat Release and Gravity

DTIC Science & Technology

1990-09-27

UNSTEADY DIFFUSION FLAME: EFFECTS OF HEAT RELEASE AND GRAVITY INTRODUCTION Experiments on laminar diffusion flames have shown that gravity affects the flame ... length and width as well as its extinction characteristics (1-4). These studies have been conducted in drop towers and have focused on fuel jets with

Formation and Release Behavior of Iron Corrosion Products under the Influence of Bacterial Communities in a Simulated Water Distribution System

EPA Science Inventory

Understanding the effects of biofilm on the iron corrosion, iron release and associated corrosion by-products is critical for maintaining the water quality and the integrity of drinking water distribution system (DWDS). In this work, iron corrosion experiments under sterilized a...

Release of ‘UI Platinum’ hard white spring wheat

USDA-ARS?s Scientific Manuscript database

‘UI Platinum’ (Reg. No. CV------, PI 672533) hard white spring wheat (Triticum aestivum L.) was developed by the Idaho Agricultural Experiment Station and released in 2014. UI Platinum was derived from the cross ‘Blanca Grande’ x ‘Jerome’ and tested under experimental numbers A01178S, IDO694, and I...

Computer Simulation of Compression and Energy Release upon Laser Irradiation of Cylindrically Symmetric Target

NASA Astrophysics Data System (ADS)

Kuzenov, V. V.

2017-12-01

The paper is devoted to the theoretical and computational study of compression and energy release for magneto-inertial plasma confinement. This approach makes it possible to create new high-density plasma sources, apply them in materials science experiments, and use them in promising areas of power engineering.

Dynamic loading and release in Johnson Space Center Lunar regolith simulant

NASA Astrophysics Data System (ADS)

Plesko, C. S.; Jensen, B. J.; Wescott, B. L.; Skinner McKee, T. E.

2011-10-01

The behavior of regolith under dynamic loading is important for the study of planetary evolution, impact cratering, and other topics. Here we present the initial results of explosively driven flier plate experiments and numerical models of compaction and release in samples of the JSC-1A Lunar regolith simulant.

Registration of Anton Hard White Winter Wheat

USDA-ARS?s Scientific Manuscript database

‘Anton’ (Reg. No. CV PI 651043) hard white winter wheat (Triticum aestivum L.) was developed by the USDA-ARS and the Nebraska Agricultural Experiment Station and released in December, 2007. "Anton" was selected from the cross WA691213-27/N86L177//‘Platte’. Anton primarily was released for its lo...

Stability of sub-Alfvenic plasma expansions

NASA Technical Reports Server (NTRS)

Huba, J. D.; Hassam, A. B.; Winske, D.

1990-01-01

A theoretical treatment of the linear stability of sub-Alfvenic plasma expansion is developed. The theory is fully kinetic and includes finite-beta effects, collisional effects, and neutral gas flow. A variety of results are obtained, and are applied to the the AMPTE magnetotail release, the NRL laser experiment, and the upcoming CRRES GTO releases.

Iron bioavailability studies of the first generation of iron-biofortified beans released in Rwanda

USDA-ARS?s Scientific Manuscript database

This paper represents a series of in vitro Fe bioavailability experiments, Fe content analysis and polyphenolic profile of the first generation of Fe biofortified beans (Phaseolus vulgaris) selected for human trials in Rwanda and released to farmers of that region. The objective of the present stud...

Notice of release of a high fiber sugarcane variety Ho 02-113

USDA-ARS?s Scientific Manuscript database

The United States Department of Agriculture’s Agricultural Research Service, Sugarcane Research Unit (SRU); the Louisiana Agricultural Experiment Station of the LSU Agricultural Center; and the American Sugar Cane League of the U.S.A, Inc., announce the release of a new high-fiber variety, Ho 02-113...

Breeding for CLEARFIELD Herbicide Tolerance: Registration of ‘ND901CL’ Spring Wheat

USDA-ARS?s Scientific Manuscript database

‘ND901CL’ (Reg. No. CV-1029, PI 655233) hard red spring wheat (HRSW) (Triticum aestivum L.) was developed at NorthDakota State University (NDSU) and released by the North Dakota Agricultural Experiment Station (NDAES). ND901CLwas released in 2008 primarily for its tolerance to imadazolinone herbicid...

Registration of BARBREN-713 Germplasm line of Upland cotton resistant to reniform and root-knot nematodes

USDA-ARS?s Scientific Manuscript database

Cotton (Gossypium hirsutum L.) germplasm line BARBREN-713 (Reg. No. ___, PI _____) was developed and released by the USDA-ARS, Mississippi Agricultural and Forest Experiment Station, Texas A&M AgriLife Research, and Cotton Incorporated in 2012. The objective of the release was to provide public and...

Acetylcholine Release in the Hippocampus and Striatum during Place and Response Training

ERIC Educational Resources Information Center

Pych, Jason C.; Chang, Qing; Colon-Rivera, Cynthia; Haag, Renee; Gold, Paul E.

2005-01-01

These experiments examined the release of acetylcholine in the hippocampus and striatum when rats were trained, within single sessions, on place or response versions of food-rewarded mazes. Microdialysis samples of extra-cellular fluid were collected from the hippocampus and striatum at 5-min increments before, during, and after training. These…

Characterization of Encapsulated Corrosion Inhibitors Containing Microparticles for Environmentally Friendly Smart Coatings

NASA Technical Reports Server (NTRS)

Pearman, Benjamin Pieter; Calle, Luz M.

2015-01-01

This poster presents the results obtained from experiments designed to evaluate the release properties, as well as the corrosion inhibition effectiveness, of several encapsulated corrosion inhibitors. Microencapsulation has been used in the development of environmentally friendly multifunctional smart coatings. This technique enables the incorporation of autonomous corrosion detection, inhibition and self-healing functionalities into many commercially available coating systems. Select environmentally friendly corrosion inhibitors were encapsulated in organic and inorganic pH-sensitive microparticles and their release in basic solutions was studied. The release rate results showed that the encapsulation can be tailored from fast, for immediate corrosion protection, to slow, which will provide continued long-term corrosion protection. The incorporation of several corrosion inhibitor release profiles into a coating provides effective corrosion protection properties. To investigate the corrosion inhibition efficiency of the encapsulated inhibitors, electrochemical techniques were used to obtain corrosion potential, polarization curve and polarization resistance data. These measurements were performed using the free as well as the encapsulated inhibitors singly or in combinations. Results from these electrochemical tests will be compared to those obtained from weight loss and other accelerated corrosion experiments.

Environmentally Dependent Density-Distance Relationship of Dispersing Culex tarsalis in a Southern California Desert Region.

PubMed

Antonić, Oleg; Sudarić-Bogojević, Mirta; Lothrop, Hugh; Merdić, Enrih

2014-09-01

The direct inclusion of environmental factors into the empirical model that describes a density-distance relationship (DDR) is demonstrated on dispersal data obtained in a capture-mark-release-recapture experiment (CMRR) with Culex tarsalis conducted around the community of Mecca, CA. Empirical parameters of standard (environmentally independent) DDR were expressed as linear functions of environmental variables: relative orientation (azimuthal deviation of north) of release point (relative to recapture point) and proportions of habitat types surrounding each recapture point. The yielded regression model (R(2)  =  0.5373, after optimization on the best subset of linear terms) suggests that spatial density of recaptured individuals after 12 days of a CMRR experiment significantly depended on 1) distance from release point, 2) orientation of recapture points in relation to release point (preferring dispersal toward the south, probably due to wind drift and position of periodically flooded habitats suitable for species egg clutches), and 3) habitat spectrum in surroundings of recapture points (increasing and decreasing population density in desert and urban environment, respectively).

Controlling the Release of Indomethacin from Glass Solutions Layered with a Rate Controlling Membrane Using Fluid-Bed Processing. Part 2: The Influence of Formulation Parameters on Drug Release.

PubMed

Dereymaker, Aswin; Pelgrims, Jirka; Engelen, Frederik; Adriaensens, Peter; Van den Mooter, Guy

2017-04-03

This study aimed to investigate the pharmaceutical performance of an indomethacin-polyvinylpyrrolidone (PVP) glass solution applied using fluid bed processing as a layer on inert sucrose spheres and subsequently top-coated with a release rate controlling membrane consisting of either ethyl cellulose or Eudragit RL. The implications of the addition of a pore former (PVP) and the coating medium (ethanol or water) on the diffusion and release behavior were also considered. In addition, the role of a charge interaction between drug and controlled release polymer on the release was investigated. Diffusion experiments pointed to the influence of pore former concentration, rate controlling polymer type, and coating solvent on the permeability of the controlled release membranes. This can be translated to drug release tests, which show the potential of diffusion tests as a preliminary screening test and that diffusion is the main factor influencing release. Drug release tests also showed the effect of coating layer thickness. A charge interaction between INDO and ERL was demonstrated, but this had no negative effect on drug release. The higher diffusion and release observed in ERL-based rate controlling membranes was explained by a higher hydrophilicity, compared to EC.

Understanding controlled drug release from mesoporous silicates: theory and experiment.

PubMed

Ukmar, T; Maver, U; Planinšek, O; Kaučič, V; Gaberšček, M; Godec, A

2011-11-07

Based on the results of carefully designed experiments upgraded with appropriate theoretical modeling, we present clear evidence that the release curves from mesoporous materials are significantly affected by drug-matrix interactions. In experimental curves, these interactions are manifested as a non-convergence at long times and an inverse dependence of release kinetics on pore size. Neither of these phenomena is expected in non-interacting systems. Although both phenomena have, rather sporadically, been observed in previous research, they have not been explained in terms of a general and consistent theoretical model. The concept is demonstrated on a model drug indomethacin embedded into SBA-15 and MCM-41 porous silicates. The experimental release curves agree exceptionally well with theoretical predictions in the case of significant drug-wall attractions. The latter are described using a 2D Fokker-Planck equation. One could say that the interactions affect the relative cross-section of pores where the local flux has a non-vanishing axial component and in turn control the effective transfer of drug into bulk solution. Finally, we identify the critical parameters determining the pore size dependence of release kinetics and construct a dynamic phase diagram of the various resulting transport regimes. Copyright © 2011 Elsevier B.V. All rights reserved.

[Preparation of ondansetron hydrochloride osmotic pump tablets and their in vitro drug release].

PubMed

Zheng, Hang-sheng; Bi, Dian-zhou

2005-12-01

To prepare ondansetron hydrochloride osmotic pump tablets (OND-OPT) and investigate their in vitro drug release behavior. OND-OPT were prepared with a single punch press and pan coating technique. Osmotic active agents and plasticizer of coating film were chosen by drug release tests. The effects of the number, position and direction of drug release orifice on release behavior were investigated. The relation between drug release duration and thickness of coating film, PEG content of coating film and size of drug release orifice was established by uniform design experiment. The surface morphological change of coating film before and after drug release test was observed by scanning electron microscopy. The osmotic pumping release mechanism of OND-OPT was confirmed by drug release test with high osmotic pressure medium. Lactose-mannitol (1:2) was chosen as osmotic active agents and PEG400 as plasticizer of coating film. The direction of drug release orifice had great effect on the drug release of OND-OPT without HPMC, and had no effect on the drug release of OND-OPT with HPMC. The OND-OPT with one drug release orifice at the centre of the coating film on one surface of tablet released their drug with little fluctuation. The drug release duration of OND-OPT correlated with thickness of coating film and PEG content of coating film, and didn't correlate significantly with the size of drug release orifice. OND-OPT released their drug with osmotic pumping mechanism predominantly. OND-OPT are able to realize ideal controlled drug release.

Acquisition of He3 Cryostat Insert for Experiments on Topological Insulators

DTIC Science & Technology

2016-02-03

facilitated transport experiments on topological insulators and Dirac and Weyl semimetals. These experiments resulted in several notable achievements and...Approved for Public Release; Distribution Unlimited Final Report: Acquisition of He3 Cryostat Insert for Experiments on Topological Insulators . The views...Experiments on Topological Insulators . Report Title The award enabled the PI to acquire a complete cryogenic system with a 9-Tesla superconducting magnet. The

Dissolution experiments of commercial PWR (52 MWd/kgU) and BWR (53 MWd/kgU) spent nuclear fuel cladded segments in bicarbonate water under oxidizing conditions. Experimental determination of matrix and instant release fraction

NASA Astrophysics Data System (ADS)

González-Robles, E.; Serrano-Purroy, D.; Sureda, R.; Casas, I.; de Pablo, J.

2015-10-01

The denominated instant release fraction (IRF) is considered in performance assessment (PA) exercises to govern the dose that could arise from the repository. A conservative definition of IRF comprises the total inventory of radionuclides located in the gap, fractures, and the grain boundaries and, if present, in the high burn-up structure (HBS). The values calculated from this theoretical approach correspond to an upper limit that likely does not correspond to what it will be expected to be instantaneously released in the real system. Trying to ascertain this IRF from an experimental point of view, static leaching experiments have been carried out with two commercial UO2 spent nuclear fuels (SNF): one from a pressurized water reactor (PWR), labelled PWR, with an average burn-up (BU) of 52 MWd/kgU and fission gas release (FGR) of 23.1%, and one from a boiling water reactor (BWR), labelled BWR, with an average BU of and 53 MWd/kgU and FGR of 3.9%. One sample of each SNF, consisting of fuel and cladding, has been leached in bicarbonate water during one year under oxidizing conditions at room temperature (25 ± 5)°C. The behaviour of the concentration measured in solution can be divided in two according to the release rate. All radionuclides presented an initial release rate that after some days levels down to a slower second one, which remains constant until the end of the experiment. Cumulative fraction of inventory in aqueous phase (FIAPc) values has been calculated. Results show faster release in the case of the PWR SNF. In both cases Np, Pu, Am, Cm, Y, Tc, La and Nd dissolve congruently with U, while dissolution of Zr, Ru and Rh is slower. Rb, Sr, Cs and Mo, dissolve faster than U. The IRF of Cs at 10 and 200 days has been calculated, being (3.10 ± 0.62) and (3.66 ± 0.73) for PWR fuel, and (0.35 ± 0.07) and (0.51 ± 0.10) for BWR fuel.

The efficacy of nimodipine drug delivery using mPEG-PLA micelles and mPEG-PLA/TPGS mixed micelles.

PubMed

Huang, Shuling; Yu, Xiaohong; Yang, Linlin; Song, Fenglan; Chen, Gang; Lv, Zhufen; Li, Tiao; Chen, De; Zhu, Wanhua; Yu, Anan; Zhang, Yongming; Yang, Fan

2014-10-15

In order to develop and compare mPEG-PLA micelles and mPEG-PLA/TPGS mixed micelles, with the intention to develop a highly efficient formulation for nimodipine (NIM), NIM-loaded micelles and mixed micelles were made and their pharmacokinetics were studied. Single factor experiments and orthogonal experiments were designed to optimize the final preparation process, characterizations and drug release behaviors were studied. Pharmacokinetics of NIM micelles, NIM mixed micelles were researched and were compared to NIM solution. Micelles and mixed micelles were prepared by solvent evaporation method, with relatively high drug loading efficiency and within nano-particle size range. The CMC value of mPEG-PLA was lower than that of mPEG-PLA/TPGS. The results of FTIR and TEM confirmed the spherical core-shell structure of micelles as well as mixed micelles, and the encapsulation of NIM inside the cores. In vitro release showed that micelles and mixed micelles had sustained release effect in the forms of passive diffusion and dissolution process, respectively. Following intraperitoneal administration (5mg/kg), micelles and mixed micelles were absorbed faster than solution, and with larger MRT(0-t), smaller CLz and larger AUC(0-t) as compared to that of solution, which showed micelles and mixed micelles had higher retention, slower elimination and higher bioavailability. This experiment also showed that mixed micelles released NIM more stably than micelles. By evaluate the bioequivalence, NIM micelles and NIM mixed micelles were testified non-bioequivalent to NIM solution. Micelles and mixed micelles could sustain the NIM concentrations more efficiently in plasma as compared to solution. Mixed micelles were the best ones since they had high loading content and released more stably. Thus, apprehending micelles and mixed micelles were suited as poor aqueous solubility drug carriers, and mixed micelles were better due to their high loading content and more stable release. Copyright © 2014 Elsevier B.V. All rights reserved.

Study of the heat-transfer crisis on heat-release surfaces of annular channels with swirl and transit flows

NASA Astrophysics Data System (ADS)

Boltenko, E. A.

2016-10-01

The results of the experimental study of the heat-transfer crisis on heat-release surfaces of annular channels with swirl and transit flow are presented. The experiments were carried out using electric heated annular channels with one and (or) two heat-release surfaces. For the organization of transit flow on a convex heat-release surface, four longitudinal ribs were installed uniformly at its perimeter. Swirl flow was realized using a capillary wound tightly (without gaps) on the ribs. The ratio between swirl and transit flows in the annular gap was varied by applying longitudinal ribs of different height. The experiments were carried out using a closed-type circulatory system. The experimental data were obtained in a wide range of regime parameters. Both water heated to the temperature less than the saturation temperature and water-steam mixture were fed at the inlet of the channels. For the measurement of the temperature of the heat-release surfaces, chromel-copel thermocouples were used. It was shown that the presence of swirl flow on a convex heatrelease surface led to a significant decrease in critical heat flows (CHF) compared to a smooth surface. To increase CHF, it was proposed to use the interaction of swirl flows of the heat carrier. The second swirl flow was transit flow, i.e., swirl flow with the step equal to infinity. It was shown that CHF values for a channel with swirl and transit flow in all the studied range of regime parameters was higher than CHF values for both a smooth annular channel and a channel with swirl. The empirical ratios describing the dependence of CHF on convex and concave heat-release surfaces of annular channels with swirl and transit flow on the geometrical characteristics of channels and the regime parameters were obtained. The experiments were carried out at the pressure p = 3.0-16.0 MPa and the mass velocity ρw = 250-3000 kg/(m2s).

Open release of male mosquitoes infected with a wolbachia biopesticide: field performance and infection containment.

PubMed

O'Connor, Linda; Plichart, Catherine; Sang, Ayo Cheong; Brelsfoard, Corey L; Bossin, Hervé C; Dobson, Stephen L

2012-01-01

Lymphatic filariasis (LF) is a globally significant disease, with 1.3 billion persons in 83 countries at risk. A coordinated effort of administering annual macrofilaricidal prophylactics to the entire at-risk population has succeeded in impacting and eliminating LF transmission in multiple regions. However, some areas in the South Pacific are predicted to persist as transmission sites, due in part to the biology of the mosquito vector, which has led to a call for additional tools to augment drug treatments. Autocidal strategies against mosquitoes are resurging in the effort against invasive mosquitoes and vector borne disease, with examples that include field trials of genetically modified mosquitoes and Wolbachia population replacement. However, critical questions must be addressed in anticipation of full field trials, including assessments of field competitiveness of transfected males and the risk of unintended population replacement. We report the outcome of field experiments testing a strategy that employs Wolbachia as a biopesticide. The strategy is based upon Wolbachia-induced conditional sterility, known as cytoplasmic incompatibility, and the repeated release of incompatible males to suppress a population. A criticism of the Wolbachia biopesticide approach is that unintended female release or horizontal Wolbachia transmission can result in population replacement instead of suppression. We present the outcome of laboratory and field experiments assessing the competitiveness of transfected males and their ability to transmit Wolbachia via horizontal transmission. The results demonstrate that Wolbachia-transfected Aedes polynesiensis males are competitive under field conditions during a thirty-week open release period, as indicated by mark, release, recapture and brood-hatch failure among females at the release site. Experiments demonstrate the males to be 'dead end hosts' for Wolbachia and that methods were adequate to prevent population replacement at the field site. The findings encourage the continued development and extension of a Wolbachia autocidal approach to additional medically important mosquito species.

A drift experiment to assess the influence of wind on recovery of oiled seabirds on St Paul Island, Alaska

USGS Publications Warehouse

Flint, Paul L.; Fowler, A.C.

1998-01-01

We used wooden blocks to estimate the proportion of oiled seabird carcasses that were likely to be recovered on beaches of St Paul Island, Alaska following a near-shore oil spill. We released a total of 302 blocks 6 km north of the island in 1997 at the site of a 17 II 1996 oil spill. We used a paired design and released half the blocks when the winds were onshore and released the second half when the winds were offshore. We systematically searched beaches after the second release to recover blocks. We recovered 93 of 152 (61%) blocks released when winds were onshore but only 1 of 150 (0.7%) blocks released when winds were offshore. Given that winds following the 1996 spill were offshore, we conclude that most birds killed at sea following the 1996 spill were likely not recovered on beaches.

Detection of the urban release of a bacillus anthracis simulant by air sampling.

PubMed

Garza, Alexander G; Van Cuyk, Sheila M; Brown, Michael J; Omberg, Kristin M

2014-01-01

In 2005 and 2009, the Pentagon Force Protection Agency (PFPA) staged deliberate releases of a commercially available organic pesticide containing Bacillus amyloliquefaciens to evaluate PFPA's biothreat response protocols. In concert with, but independent of, these releases, the Department of Homeland Security sponsored experiments to evaluate the efficacy of commonly employed air and surface sampling techniques for detection of an aerosolized biological agent. High-volume air samplers were placed in the expected downwind plume, and samples were collected before, during, and after the releases. Environmental surface and personal air samples were collected in the vicinity of the high-volume air samplers hours after the plume had dispersed. The results indicate it is feasible to detect the release of a biological agent in an urban area both during and after the release of a biological agent using high-volume air and environmental sampling techniques.

The Influence of Glutamate on Axonal Compound Action Potential In Vitro.

PubMed

Abouelela, Ahmed; Wieraszko, Andrzej

2016-01-01

Background  Our previous experiments demonstrated modulation of the amplitude of the axonal compound action potential (CAP) by electrical stimulation. To verify assumption that glutamate released from axons could be involved in this phenomenon, the modification of the axonal CAP induced by glutamate was investigated. Objectives  The major objective of this research is to verify the hypothesis that axonal activity would trigger the release of glutamate, which in turn would interact with specific axonal receptors modifying the amplitude of the action potential. Methods  Segments of the sciatic nerve were exposed to exogenous glutamate in vitro, and CAP was recorded before and after glutamate application. In some experiments, the release of radioactive glutamate analog from the sciatic nerve exposed to exogenous glutamate was also evaluated. Results  The glutamate-induced increase in CAP was blocked by different glutamate receptor antagonists. The effect of glutamate was not observed in Ca-free medium, and was blocked by antagonists of calcium channels. Exogenous glutamate, applied to the segments of sciatic nerve, induced the release of radioactive glutamate analog, demonstrating glutamate-induced glutamate release. Immunohistochemical examination revealed that axolemma contains components necessary for glutamatergic neurotransmission. Conclusion  The proteins of the axonal membrane can under the influence of electrical stimulation or exogenous glutamate change membrane permeability and ionic conductance, leading to a change in the amplitude of CAP. We suggest that increased axonal activity leads to the release of glutamate that results in changes in the amplitude of CAPs.

pH-independent immediate release polymethacrylate formulations--an observational study.

PubMed

Claeys, Bart; Vandeputte, Reinout; De Geest, Bruno G; Remon, Jean Paul; Vervaet, Chris

2016-01-01

Using Eudragit® E PO (EudrE) as a polymethacrylate carrier, the aim of the study was to develop a pH-independent dosage form containing ibuprofen (IBP) as an active compound via chemical modification of the polymer (i.e. quaternization of amine function) or via the addition of dicarboxylic acids (succinic, glutaric and adipic acid) to create a pH micro-environment during dissolution. Biconvex tablets (diameter: 10 mm; height: 5 mm) were produced via hot melt extrusion and injection molding. In vitro dissolution experiments revealed that a minimum of 25% of quaternization was sufficient to partially (up to pH 5) eliminate the pH-dependent effect of the EudrE/IBP formulation. The addition of dicarboxylic acids did not alter IBP release in a pH 1 and 3 medium as the dimethyl amino groups of EudrE are already fully protonated, while in a pH 5 solvent IBP release was significantly improved (cf. from 0% to 92% release after 1 h dissolution experiments upon the addition of 20 wt.% succinic acid). Hence, both approaches resulted in a pH-independent (up to pH 5) immediate release formulation. However, the presence of a positively charged polymer induced stability issues (recrystallization of API) and the formulations containing dicarboxylic acids were classified as mechanically unstable. Hence, further research is needed to obtain a pH-independent immediate release formulation while using EudrE as a polmethacrylate carrier.

Measurement and modeling of oil slick transport

NASA Astrophysics Data System (ADS)

Jones, Cathleen E.; Dagestad, Knut-Frode; Breivik, Øyvind; Holt, Benjamin; Röhrs, Johannes; Christensen, Kai Hâkon; Espeseth, Martine; Brekke, Camilla; Skrunes, Stine

2016-10-01

Transport characteristics of oil slicks are reported from a controlled release experiment conducted in the North Sea in June 2015, during which mineral oil emulsions of different volumetric oil fractions and a look-alike biogenic oil were released and allowed to develop naturally. The experiment used the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) to track slick location, size, and shape for ˜8 h following release. Wind conditions during the exercise were at the high end of the range considered suitable for radar-based slick detection, but the slicks were easily detectable in all images acquired by the low noise, L-band imaging radar. The measurements are used to constrain the entrainment length and representative droplet radii for oil elements in simulations generated using the OpenOil advanced oil drift model. Simultaneously released drifters provide near-surface current estimates for the single biogenic release and one emulsion release, and are used to test model sensitivity to upper ocean currents and mixing. Results of the modeling reveal a distinct difference between the transport of the biogenic oil and the mineral oil emulsion, in particular in the vertical direction, with faster and deeper entrainment of significantly smaller droplets of the biogenic oil. The difference in depth profiles for the two types of oils is substantial, with most of the biogenic oil residing below depths of 10 m, compared to the majority of the emulsion remaining above 10 m depth. This difference was key to fitting the observed evolution of the two different types of slicks.

Using EPSAT to analyze high power systems in the space environment. [Environment Power System Analysis Tool

NASA Technical Reports Server (NTRS)

Kuharski, Robert A.; Jongeward, Gary A.; Wilcox, Katherine G.; Rankin, Tom R.; Roche, James C.

1991-01-01

The authors review the Environment Power System Analysis Tool (EPSAT) design and demonstrate its capabilities by using it to address some questions that arose in designing the SPEAR III experiment. It is shown that that the rocket body cannot be driven to large positive voltages under the constraints of this experiment. Hence, attempts to measure the effects of a highly positive rocket body in the plasma environment should not be made in this experiment. It is determined that a hollow cathode will need to draw only about 50 mA to ground the rocket body. It is shown that a relatively small amount of gas needs to be released to induce a bulk breakdown near the rocket body, and this gas release should not discharge the sphere. Therefore, the experiment provides an excellent opportunity to study the neutralization of a differential charge.

Non-invasive continuous imaging of drug release from soy-based skin equivalent using wide-field interferometry

NASA Astrophysics Data System (ADS)

Gabai, Haniel; Baranes-Zeevi, Maya; Zilberman, Meital; Shaked, Natan T.

2013-04-01

We propose an off-axis interferometric imaging system as a simple and unique modality for continuous, non-contact and non-invasive wide-field imaging and characterization of drug release from its polymeric device used in biomedicine. In contrast to the current gold-standard methods in this field, usually based on chromatographic and spectroscopic techniques, our method requires no user intervention during the experiment, and only one test-tube is prepared. We experimentally demonstrate imaging and characterization of drug release from soy-based protein matrix, used as skin equivalent for wound dressing with controlled anesthetic, Bupivacaine drug release. Our preliminary results demonstrate the high potential of our method as a simple and low-cost modality for wide-field imaging and characterization of drug release from drug delivery devices.

Helium release during shale deformation: Experimental validation

DOE PAGES

Bauer, Stephen J.; Gardner, W. Payton; Heath, Jason E.

2016-07-01

This paper describes initial experimental results of helium tracer release monitoring during deformation of shale. Naturally occurring radiogenic 4He is present in high concentration in most shales. During rock deformation, accumulated helium could be released as fractures are created and new transport pathways are created. We present the results of an experimental study in which confined reservoir shale samples, cored parallel and perpendicular to bedding, which were initially saturated with helium to simulate reservoir conditions, are subjected to triaxial compressive deformation. During the deformation experiment, differential stress, axial, and radial strains are systematically tracked. Release of helium is dynamically measuredmore » using a helium mass spectrometer leak detector. Helium released during deformation is observable at the laboratory scale and the release is tightly coupled to the shale deformation. These first measurements of dynamic helium release from rocks undergoing deformation show that helium provides information on the evolution of microstructure as a function of changes in stress and strain.« less

The Viking mission search for life on Mars

NASA Technical Reports Server (NTRS)

Klein, H. P.; Lederberg, J.; Rich, A.; Horowitz, N. H.; Oyama, V. I.; Levin, G. V.

1976-01-01

The scientific payload on the Viking Mars landers is described. Shortly after landing, two facsimile cameras capable of stereoscopic imaging will scan the landing site area in black and white, color, and infrared to reveal gross evidence of past or present living systems. A wide range mass spectrometer will record a complete mass spectrum for soil samples from mass 12 to mass 200 every 10.3 sec. Three experiments based on different assumptions on the nature of life on Mars, if it exists, will be carried out by the bio-lab. A pyrolytic release experiment is designed to measure photosynthetic or dark fixation of carbon dioxide or carbon monoxide into organic compounds. A labelled release experiment will test for metabolic activity during incubation of a surface sample moistened with a solution of radioactively labelled simple organic compounds. A gas exchange experiment will detect changes in the gaseous medium surrounding a soil sample as the result of metabolic activity. The hardware, function, and terrestrial test results of the bio-lab experiments are discussed.

Injection-induced moment release can also be aseismic

USGS Publications Warehouse

McGarr, Arthur; Barbour, Andrew J.

2018-01-01

The cumulative seismic moment is a robust measure of the earthquake response to fluid injection for injection volumes ranging from 3100 to about 12 million m3. Over this range, the moment release is limited to twice the product of the shear modulus and the volume of injected fluid. This relation also applies at the much smaller injection volumes of the field experiment in France reported by Guglielmi, et al. (2015) and laboratory experiments to simulate hydraulic fracturing described by Goodfellow, et al. (2015). In both of these studies, the relevant moment release for comparison with the fluid injection was aseismic and consistent with the scaling that applies to the much larger volumes associated with injection-induced earthquakes with magnitudes extending up to 5.8. Neither the micro-earthquakes, at the site in France, nor the acoustic emission in the laboratory samples contributed significantly to the deformation due to fluid injection.

New student-designed research and demonstration drop tower

NASA Astrophysics Data System (ADS)

Bell, Donald; Weislogel, Mark

A new drop tower has been designed and constructed at Portland State University. The ap-proach incorporates innovative features to increase throughput and microgravity quality in a highly public facility. Push button operation with full wireless CCTV coverage and passive magnetic deceleration provides quiet, safe operation from a single control station with low re-cycle time. A two-stage coaxial release mechanism decouples the payload from the drag shield to minimize disturbances to the experiment during release. This is especially important for fluids experiments that are highly sensitive to initial conditions. Performance of the new tower is presented including release, free fall, and deceleration accelerometer data. The two second tower is used for research and educational outreach. The research efforts focus on capillary flows and phenomena relevant to spacecraft fluid systems. The outreach efforts utilize partnerships with local primary, secondary and post-secondary institutions to promote the fields of science, technology, engineering and mathematics.

A natural experiment of the consequences of concentrating former prisoners in the same neighborhoods.

PubMed

Kirk, David S

2015-06-02

More than 600,000 prisoners are released from incarceration each year in the United States, and most end up residing in metropolitan areas, clustered within a select few neighborhoods. Likely consequences of this concentration of returning prisoners include higher rates of subsequent crime and recidivism. In fact, one-half of released prisoners return to prison within only 3 y of release. The routine exposure to criminogenic influences and criminal opportunities portends a bleak future for individuals who reside in neighborhoods with numerous other ex-prisoners. Through a natural experiment focused on post-Hurricane Katrina Louisiana, I examine a counterfactual scenario: If instead of concentrating ex-prisoners in geographic space, what would happen to recidivism rates if ex-prisoners were dispersed across space? Findings reveal that a decrease in the concentration of parolees in a neighborhood leads to a significant decrease in the reincarceration rate of former prisoners.

Dissolution of lanthanide alumino-silicate oxynitride glasses

NASA Astrophysics Data System (ADS)

Bois, L.; Barré, N.; Guillopé, S.; Guittet, M. J.; Gautier-Soyer, M.; Duraud, J. P.; Trocellier, P.; Verdier, P.; Laurent, Y.

2000-01-01

The aqueous corrosion behavior of lanthanide aluminosilicate glasses has been studied under static conditions ( T=96°C, duration=1 and 3 months, glass surface area/leachate volume, S/ V=0.3 cm -1) by means of solution and solid analyses. It was found that these glasses exhibit a high chemical durability. The influence of yttrium, magnesium and nitrogen, which are supposed to improve the mechanical properties, on the chemical durability, has been investigated. After a one-month experiment, lanthanum and yttrium releases were found to be about 10 -7 mol l -1, while silicon and aluminum releases were about 10 -5 mol l -1. Yttrium seems to improve the chemical durability. The presence of nitrogen does not seem to modify the glass constituents releases, but seems to improve the surface state of the altered glass. XPS experiments reveal that lanthanum and yttrium are more concentrated near the surface (20-30 Å) of the glass after the leaching test.

Viking gas exchange reaction - Simulation on UV-irradiated manganese dioxide substrate

NASA Technical Reports Server (NTRS)

Blackburn, T. R.; Holland, H. D.; Ceasar, G. P.

1979-01-01

The exchange of O2 for H2O, analogous to that recorded on Mars by the Viking GEX experiment, has been observed on humidifying powdered beta-MnO2 (pyrolusite) which had been irradiated by UV in a humidified analog of the Martian atmosphere. Pyrolusite irradiated in a dry atmosphere did not release O2 on humidification. The XPS spectra of Mn and O of the reactive pyrolusite were shifted toward higher binding energies during UV irradiation. These shifts are consistent with the creation of a surface layer of a Mn(V) or Mn(VI) compound. The destruction of such a layer on humidification could account for the observed O2 release. Although manganese has not been identified in the Martian regolith, the upper limit of the Mn concentration is sufficiently high that O2 release from pyrolusite could have been responsible for the results of the Viking GEX experiment.

A natural experiment of the consequences of concentrating former prisoners in the same neighborhoods

PubMed Central

Kirk, David S.

2015-01-01

More than 600,000 prisoners are released from incarceration each year in the United States, and most end up residing in metropolitan areas, clustered within a select few neighborhoods. Likely consequences of this concentration of returning prisoners include higher rates of subsequent crime and recidivism. In fact, one-half of released prisoners return to prison within only 3 y of release. The routine exposure to criminogenic influences and criminal opportunities portends a bleak future for individuals who reside in neighborhoods with numerous other ex-prisoners. Through a natural experiment focused on post-Hurricane Katrina Louisiana, I examine a counterfactual scenario: If instead of concentrating ex-prisoners in geographic space, what would happen to recidivism rates if ex-prisoners were dispersed across space? Findings reveal that a decrease in the concentration of parolees in a neighborhood leads to a significant decrease in the reincarceration rate of former prisoners. PMID:25976097

Influences of pH and CO2 on the formation of Metasilicate mineral water in Changbai Mountain, Northeast China

NASA Astrophysics Data System (ADS)

Yan, Baizhong; Xiao, Changlai; Liang, Xiujuan; Wu, Shili

2017-07-01

Mineral dissolution reactions actively participate in controlling the composition of mineral water. In this study, water soluble, acidic-alkaline and carbonated solution experiments were designed, and mineral reaction mechanisms were researched using chemical kinetics and the minimum free-energy method. The results showed that the release of metasilicate was controlled by pH, CO2, and rock characteristics. In the water soluble experiment, the release process of metasilicate in powdered rocks reached equilibrium after 40 days, while metasilicate in solid rocks took 170 days. The release process of metasilicate in solid rocks satisfied an asymptotic model, while in powdered rocks it accorded with the Stanford reaction kinetic model. In the acidic-alkaline experiment, metasilicate was released earlier under acidic conditions (2.46 < pH < 7) than under alkaline conditions (7 < pH < 10.61). The release process of metasilicate under acidic conditions reached equilibrium in 40 days, compared with 60 days for alkaline conditions. The addition of CO2 to the water solution was beneficial to the formation of metasilicate. Under neutral pH conditions, the reaction barely occurred. Under alkaline conditions, metasilicate was produced by the hydrolysis of metasilicate minerals. Under acidic and additional CO2 conditions, metasilicate formation was mainly via the reaction of H+, CO2, and metasilicate minerals. From these results, we concluded that the metasilicate mineral water from the Changbai Mountains, Jingyu County, is generated by a combination of the hydrolysis of metasilicate minerals and the reaction of H+, CO2, and metasilicate minerals. These results can contribute to a better development and protection of the mineral water resources in the Changbai Mountains.

[Study on preparation and release mechanism of effervescent osmotic pump tablet of compound Danshen].

PubMed

Xue, Li'an; Li, Yuanbo; Guo, Dandan; Yin, Jianhua; Liu, Yanchun; Hou, Shixiang

2009-04-01

To prepare effervescent osmotic pump tablet (EOPTs) according to the rhythm of coronary heart disease based on efficacy material and the mechanism of compound Danshen and to study the mechanism of drug released of that tablets. Since compound Danshen consist of compounds with polyphenolic groups or carboxyl groups, such as phenolic acids, flavonoids, and triterpenoids that they were acidic. EOPTs were prepared from tablet cores which containing NaHCO3 as effervescent, NaCL and manitol as osmotic agents, HPMC as retarding agents coating with CA membrane. And study the mechanism of drug released according to the change of tablet osmotic pressure. The results of in vitro experiments showed that no difference was observed among the profiles of Danshensu, protocatechuic aldehyde, ginsenoside Rg1, Rb1, notoginsenoside R1 release EOPTs. The drug was completely released from the device with a zero-order release rate over 12 h. EOPTs are Successfully obtained EOPT which the drug is released from the device over 12 h and the release mechanism of EOPTs is explained.

GS 455534 selectively suppresses binge eating of palatable food and attenuates dopamine release in the accumbens of sugar-bingeing rats.

PubMed

Bocarsly, Miriam E; Hoebel, Bartley G; Paredes, Daniel; von Loga, Isabell; Murray, Susan M; Wang, Miaoyuan; Arolfo, Maria P; Yao, Lina; Diamond, Ivan; Avena, Nicole M

2014-04-01

Binge eating palatable foods has been shown to have behavioral and neurochemical similarities to drug addiction. GS 455534 is a highly selective reversible aldehyde dehydrogenase 2 inhibitor that has been shown to reduce alcohol and cocaine intake in rats. Given the overlaps between binge eating and drug abuse, we examined the effects of GS 455534 on binge eating and subsequent dopamine release. Sprague-Dawley rats were maintained on a sugar (experiment 1) or fat (experiment 2) binge eating diet. After 25 days, GS 455534 was administered at 7.5 and 15 mg/kg by an intraperitoneal injection, and food intake was monitored. In experiment 3, rats with cannulae aimed at the nucleus accumbens shell were maintained on the binge sugar diet for 25 days. Microdialysis was performed, during which GS 455534 15 mg/kg was administered, and sugar was available. Dialysate samples were analyzed to determine extracellular levels of dopamine. In experiment 1, GS 455534 selectively decreased sugar intake food was made available in the Binge Sugar group but not the Ad libitum Sugar group, with no effect on chow intake. In experiment 2, GS 455534 decreased fat intake in the Binge Fat group, but not the Ad libitum Fat group, however, it also reduced chow intake. In experiment 3, GS 455534 attenuated accumbens dopamine release by almost 50% in binge eating rats compared with the vehicle injection. The findings suggest that selective reversible aldehyde dehydrogenase 2 inhibitors may have the therapeutic potential to reduce binge eating of palatable foods in clinical populations.

Listeners Experience Linguistic Masking Release in Noise-Vocoded Speech-in-Speech Recognition.

PubMed

Viswanathan, Navin; Kokkinakis, Kostas; Williams, Brittany T

2018-02-15

The purpose of this study was to evaluate whether listeners with normal hearing perceiving noise-vocoded speech-in-speech demonstrate better intelligibility of target speech when the background speech was mismatched in language (linguistic release from masking [LRM]) and/or location (spatial release from masking [SRM]) relative to the target. We also assessed whether the spectral resolution of the noise-vocoded stimuli affected the presence of LRM and SRM under these conditions. In Experiment 1, a mixed factorial design was used to simultaneously manipulate the masker language (within-subject, English vs. Dutch), the simulated masker location (within-subject, right, center, left), and the spectral resolution (between-subjects, 6 vs. 12 channels) of noise-vocoded target-masker combinations presented at +25 dB signal-to-noise ratio (SNR). In Experiment 2, the study was repeated using a spectral resolution of 12 channels at +15 dB SNR. In both experiments, listeners' intelligibility of noise-vocoded targets was better when the background masker was Dutch, demonstrating reliable LRM in all conditions. The pattern of results in Experiment 1 was not reliably different across the 6- and 12-channel noise-vocoded speech. Finally, a reliable spatial benefit (SRM) was detected only in the more challenging SNR condition (Experiment 2). The current study is the first to report a clear LRM benefit in noise-vocoded speech-in-speech recognition. Our results indicate that this benefit is available even under spectrally degraded conditions and that it may augment the benefit due to spatial separation of target speech and competing backgrounds.

Evaluating the patient experience after implantation of a 0.4 mg sustained release dexamethasone intracanalicular insert (Dextenza™): results of a qualitative survey.

PubMed

Gira, Joseph P; Sampson, Reginald; Silverstein, Steven M; Walters, Thomas R; Metzinger, Jamie Lynne; Talamo, Jonathan H

2017-01-01

The purpose of this study is to evaluate the patient experience of sustained release dexamethasone intracanalicular insert (Dextenza™) following cataract surgery as part of a Phase III clinical trial program. This cross-sectional, qualitative evaluation involved individual interviews lasting approximately 45 minutes. Patients from four US investigational study sites who had previously received an insert were enrolled. There were no predesignated end points; this was a qualitative survey seeking a deeper understanding of patient experience. Twenty-five patients were interviewed. Most patients (92%) reported the highest level of satisfaction grade with regard to overall product satisfaction. All patients described the insert as comfortable. Most patients (96%) described their overall experience with the insert as very convenient or extremely convenient. Twenty-two of 23 (96%) participants rated their experience with the insert as "very" or "extremely convenient", compared to previous topical therapy, and 88% of patients stated that if they were to undergo cataract surgery again, they would request the insert. When asked if they would recommend the insert to family members or friends, 92% stated they would. The survey found that 84% of participants would be willing to pay more for the insert than for eye drop therapy. The dexamethasone insert was found by patients to be highly favorable with regard to overall satisfaction, convenience, and comfort. The insert was well received and largely preferred over topical therapy alternatives following surgery. More extensive evaluation of the patient experience is warranted, and future studies should help inform design of the next generation of sustained release drug delivery systems.

Substance Abuse Treatment, Anticipated Maternal Roles, and Reentry Success of Drug-Involved Women Prisoners

ERIC Educational Resources Information Center

Robbins, Cynthia A.; Martin, Steven S.; Surratt, Hilary L.

2009-01-01

This article reports analyses of recidivism and relapse experiences of substance-abusing women inmates as they reenter the community. Outcomes are compared for women who completed a work-release therapeutic community program, women who entered but did not complete the program, and those who did not receive work-release therapeutic community…

Simulating Real-World Exposures during Emergency Events: Studying Effects of Indoor and Outdoor Releases in the Urban Dispersion Project in Upper Manhattan, NY

EPA Science Inventory

A prospective personal exposure study, involving indoor and outdoor releases, was conducted in upper Midtown Manhattan in New York City as part of the Urban Dispersion Program (UDP) focusing on atmospheric dispersion of chemicals in complex urban settings. The UDP experiments inv...

Voyager 2 Jupiter encounter

NASA Technical Reports Server (NTRS)

1979-01-01

A NASA News Release is presented which contains the following: (1) general release; (2) two views of Voyager 2 flight past Jupiter; (3) Voyager mission summary; (4) Voyager 1 science results; (5) Jupiter science objectives; (6) Jupiter the planet and its satellites; (7) Voyager experiments; (8) planet comparison; (9) a list of Voyager science investigators and (10) the Voyager team.

Fermilab | Tritium at Fermilab | Tritium released into the air and disposed

Science.gov Websites

Science Jobs Contact Phone Book Newsroom Newsroom News and features Press releases Photo gallery Fact Tevatron experiments Tevatron operation Shutdown process For the media Video of shutdown event Guest book Security, Privacy, Legal Use of Cookies Quick Links Home Contact Phone Book Fermilab at Work For Industry

Benefits of pre-release population genetics: a case study using Psyttalia lounsburyi, a biocontrol agent of the olive fruit fly in California

USDA-ARS?s Scientific Manuscript database

From a pest management perspective, limited knowledge on the genetics of released biocontrol agents has been repeatedly considered as one possible cause of failures in classical biological control. Introduced biocontrol agents are expected to experience a loss in genetic diversity as the result of s...

Impacts of an ethanol-blended fuel release on groundwater and fate of produced methane: Simulation of field observations

EPA Science Inventory

In a field experiment at Vandenberg Air Force Base (VAFB) designed to mimic the impact of a small-volume release of E10, two plumes were created by injecting extracted groundwater spiked with benzene, toluene, and o-xylene, abbreviated BToX (No-Ethanol Lane) and BToX plus ethanol...

Calcium buffering properties of sarcoplasmic reticulum and calcium-induced Ca2+ release during the quasi-steady level of release in twitch fibers from frog skeletal muscle

PubMed Central

Fénelon, Karine; Lamboley, Cédric R.H.; Carrier, Nicole

2012-01-01

Experiments were performed to characterize the properties of the intrinsic Ca2+ buffers in the sarcoplasmic reticulum (SR) of cut fibers from frog twitch muscle. The concentrations of total and free calcium ions within the SR ([CaT]SR and [Ca2+]SR) were measured, respectively, with the EGTA/phenol red method and tetramethylmurexide (a low affinity Ca2+ indicator). Results indicate SR Ca2+ buffering was consistent with a single cooperative-binding component or a combination of a cooperative-binding component and a linear binding component accounting for 20% or less of the bound Ca2+. Under the assumption of a single cooperative-binding component, the most likely resting values of [Ca2+]SR and [CaT]SR are 0.67 and 17.1 mM, respectively, and the dissociation constant, Hill coefficient, and concentration of the Ca-binding sites are 0.78 mM, 3.0, and 44 mM, respectively. This information can be used to calculate a variable proportional to the Ca2+ permeability of the SR, namely d[CaT]SR/dt ÷ [Ca2+]SR (denoted release permeability), in experiments in which only [CaT]SR or [Ca2+]SR is measured. In response to a voltage-clamp step to −20 mV at 15°C, the release permeability reaches an early peak followed by a rapid decline to a quasi-steady level that lasts ∼50 ms, followed by a slower decline during which the release permeability decreases by at least threefold. During the quasi-steady level of release, the release amplitude is 3.3-fold greater than expected from voltage activation alone, a result consistent with the recruitment by Ca-induced Ca2+ release of 2.3 SR Ca2+ release channels neighboring each channel activated by its associated voltage sensor. Release permeability at −60 mV increases as [CaT]SR decreases from its resting physiological level to ∼0.1 of this level. This result argues against a release termination mechanism proposed in mammalian muscle fibers in which a luminal sensor of [Ca2+]SR inhibits release when [CaT]SR declines to a low level. PMID:23008434

Calcium buffering properties of sarcoplasmic reticulum and calcium-induced Ca(2+) release during the quasi-steady level of release in twitch fibers from frog skeletal muscle.

PubMed

Fénelon, Karine; Lamboley, Cédric R H; Carrier, Nicole; Pape, Paul C

2012-10-01

Experiments were performed to characterize the properties of the intrinsic Ca(2+) buffers in the sarcoplasmic reticulum (SR) of cut fibers from frog twitch muscle. The concentrations of total and free calcium ions within the SR ([Ca(T)](SR) and [Ca(2+)](SR)) were measured, respectively, with the EGTA/phenol red method and tetramethylmurexide (a low affinity Ca(2+) indicator). Results indicate SR Ca(2+) buffering was consistent with a single cooperative-binding component or a combination of a cooperative-binding component and a linear binding component accounting for 20% or less of the bound Ca(2+). Under the assumption of a single cooperative-binding component, the most likely resting values of [Ca(2+)](SR) and [Ca(T)](SR) are 0.67 and 17.1 mM, respectively, and the dissociation constant, Hill coefficient, and concentration of the Ca-binding sites are 0.78 mM, 3.0, and 44 mM, respectively. This information can be used to calculate a variable proportional to the Ca(2+) permeability of the SR, namely d[Ca(T)](SR)/dt ÷ [Ca(2+)](SR) (denoted release permeability), in experiments in which only [Ca(T)](SR) or [Ca(2+)](SR) is measured. In response to a voltage-clamp step to -20 mV at 15°C, the release permeability reaches an early peak followed by a rapid decline to a quasi-steady level that lasts ~50 ms, followed by a slower decline during which the release permeability decreases by at least threefold. During the quasi-steady level of release, the release amplitude is 3.3-fold greater than expected from voltage activation alone, a result consistent with the recruitment by Ca-induced Ca(2+) release of 2.3 SR Ca(2+) release channels neighboring each channel activated by its associated voltage sensor. Release permeability at -60 mV increases as [Ca(T)](SR) decreases from its resting physiological level to ~0.1 of this level. This result argues against a release termination mechanism proposed in mammalian muscle fibers in which a luminal sensor of [Ca(2+)](SR) inhibits release when [Ca(T)](SR) declines to a low level.

Herbivorous snails can increase water clarity by stimulating growth of benthic algae.

PubMed

Zhang, Xiufeng; Taylor, William D; Rudstam, Lars G

2017-11-01

Eutrophication in shallow lakes is characterized by a switch from benthic to pelagic dominance of primary productivity that leads to turbid water, while benthification is characterized by a shift in primary production from the pelagic zone to the benthos associated with clear water. A 12-week mesocosm experiment tested the hypothesis that the herbivorous snail Bellamya aeruginosa stimulates the growth of pelagic algae through grazing on benthic algae and through accelerating nutrient release from sediment. A tube-microcosm experiment using 32 P-PO 4 as a tracer tested the effects of the snails on the release of sediment phosphorus (P). The mesocosm experiment recorded greater total nitrogen (TN) concentrations and a higher ratio of TN:TP in the overlying water, and a higher light intensity and biomass of benthic algae as measured by chlorophyll a (Chl a) in the snail treatment than in the control. Concentrations of total phosphorus (TP), total suspended solids (TSSs), and inorganic suspended solids (ISSs) in the overlying water were lower in the snail treatment than in the control, though no significant difference in Chl a of pelagic algae between the snail treatment and control was observed. In the microcosm experiment, 32 P activity in the overlying water was higher in the snail treatment than in the control, indicating that snails accelerated P release from the sediment. Our interpretation of these results is that snails enhanced growth of benthic algae and thereby improved water clarity despite grazing on the benthic algae and enhancing P release from the sediment. The rehabilitation of native snail populations may therefore enhance the recovery of eutrophic shallow lakes to a clear water state by stimulating growth of benthic algae.

The meaning and mental health consequences of long-term immigration detention for people seeking asylum.

PubMed

Coffey, Guy J; Kaplan, Ida; Sampson, Robyn C; Tucci, Maria Montagna

2010-06-01

The aim of the present research was to examine the experience of extended periods of immigration detention from the perspective of previously detained asylum seekers and to identify the consequences of these experiences for life after release. The study sample comprised seventeen adult refugees (sixteen male and one female; average age 42 years), who had been held in immigration detention funded by the Australian government for on average three years and two months. They were interviewed on average three years and eight months following their release and had been granted permanent visa status or such status was imminent. The study employed a combination of qualitative and quantitative methods to explore detention and post-detention experiences, and mental health some years after release. The qualitative component consisted of semi-structured interviews exploring psychological well-being, daily life, significant events, relationships, and ways of coping throughout these periods. This was supplemented with standardised quantitative measures of current mental health and quality of life. All participants were struggling to rebuild their lives in the years following release from immigration detention, and for the majority the difficulties experienced were pervasive. Participants suffered an ongoing sense of insecurity and injustice, difficulties with relationships, profound changes to view of self and poor mental health. Depression and demoralisation, concentration and memory disturbances, and persistent anxiety were very commonly reported. Standardised measures found high rates of depression, anxiety, PTSD and low quality of life scores. The results strongly suggest that the psychological and interpersonal difficulties participants were suffering at the time of interview were the legacy of their adverse experiences while detained. The current study assists in identifying the characteristics of prolonged immigration detention producing long-term psychological harm. Copyright 2010 Elsevier Ltd. All rights reserved.

Calcium release and its voltage dependence in frog cut muscle fibers equilibrated with 20 mM EGTA

PubMed Central

1995-01-01

Sarcoplasmic reticulum (SR) Ca release was studied at 13-16 degrees C in cut fibers (sarcomere length, 3.4-3.9 microns) mounted in a double Vaseline-gap chamber. The amplitude and duration of the action- potential stimulated free [Ca] transient were reduced by equilibration with end-pool solutions that contained 20 mM EGTA with 1.76 mM Ca and 0.63 mM phenol red, a maneuver that appeared to markedly reduce the amount of Ca complexed by troponin. A theoretical analysis shows that, under these conditions, the increase in myoplasmic free [Ca] is expected to be restricted to within a few hundred nanometers of the SR Ca release sites and to have a time course that essentially matches that of release. Furthermore, almost all of the Ca that is released from the SR is expected to be rapidly bound by EGTA and exchanged for protons with a 1:2 stoichiometry. Consequently, the time course of SR Ca release can be estimated by scaling the delta pH signal measured with phenol red by -beta/2. The value of beta, the buffering power of myoplasm, was determined in fibers equilibrated with a combination of EGTA, phenol red, and fura-2; its mean value was 22 mM/pH unit. The Ca content of the SR (expressed as myoplasmic concentration) was estimated from the total amount of Ca released by either a train of action potentials or a depleting voltage step; its mean value was 2,685 microM in the action-potential experiments and 2,544 microM in the voltage- clamp experiments. An action potential released, on average, 0.14 of the SR Ca content with a peak rate of release of approximately 5%/ms. A second action potential, elicited 20 ms later, released only 0.6 times as much Ca (expressed as a fraction of the SR content), probably because Ca inactivation of Ca release was produced by the first action potential. During a depolarizing voltage step to 60 mV, the rate of Ca release rapidly increased to a peak value of approximately 3%/ms and then decreased to a quasi-steady level that was only 0.6 times as large; this decrease was also probably due to Ca inactivation of Ca release. SR Ca release was studied with small step depolarizations that open no more than one SR Ca channel in 7,000 and increase the value of spatially averaged myoplasmic free [Ca] by only 0.2 nM. PMID:8537818

[Nutrient use efficiency and yield-increasing effect of single basal application of rice specific controlled release fertilizer].

PubMed

Chen, Jiansheng; Xu, Peizhi; Tang, Shuanhu; Zhang, Fabao; Xie, Chunsheng

2005-10-01

A series of pot and field experiments and field demonstrations showed that in comparing with the commonly used specific-fertilizers containing same amounts of nutrients, single basal application of rice-specific controlled release fertilizer could increase the use efficiency of N and P by 12.2% - 22.7% and 7.0% - 35.0%, respectively in pot experiment, and the use efficiency of N by 17.1% in field experiment. In 167 field demonstrations successively conducted for 3 years in various rice production areas of Guangdong Province, single basal application of the fertilizer saved the application rate of N and P by 22.1% and 21.8%, respectively, and increased the yield by 8.2%, compared with normal split fertilization.

Reflections of Academic Experiences from Formerly Incarcerated African American Males

ERIC Educational Resources Information Center

Jeffers, Adam R.

2017-01-01

This research examines academic experiences of African American males (ages 18-25) who attended urban schools in southern California. The participants were incarcerated for at least one year prior to being housed in a pre-release program where they reflected on their academic experiences and perceptions of the school environment. The participants'…

Experiments On Flow In A Coronary Artery

NASA Technical Reports Server (NTRS)

Back, Lloyd H.; Kwack, Eug-Yon; Liem, Timothy K.; Crawford, Donald W.

1993-01-01

Report describes experiments on simulated flow of blood in atherosclerotic human coronary artery. Experiments performed on polyurethane cast made from S-shaped coronary artery of cadaver. Sucrose solution with viscosity of blood pumped through cast at physiologically realistic rates, and flow made pulsatile by mechanism alternately compressing and releasing elastic tube just upstream of cast.

History of Los Alamos Participation in Active Experiments in Space

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

Pongratz, Morris B.

Beginning with the Teak nuclear test in 1958, Los Alamos has a long history of participation in active experiments in space. The last pertinent nuclear tests were the five explosions as part of the Dominic series in 1962. The Partial Test Ban Treaty signed in August 1963 prohibited all test detonations of nuclear weapons except for those conducted underground. Beginning with the “Apple” thermite barium release in June 1968 Los Alamos has participated in nearly 100 non-nuclear experiments in space, the last being the NASA-sponsored “AA-2” strontium and europium doped barium thermite releases in the Arecibo beam in July ofmore » 1992. The rationale for these experiments ranged from studying basic plasma processes such as gradientdriven structuring and velocity-space instabilities to illuminating the convection of plasmas in the ionosphere and polar cap to ionospheric depletion experiments to the B.E.A.R. 1-MeV neutral particle beam test in 1989. This report reviews the objectives, techniques and diagnostics of Los Alamos participation in active experiments in space.« less

Environmentally induced (co)variance in sperm and offspring phenotypes as a source of epigenetic effects.

PubMed

Marshall, Dustin J

2015-01-01

Traditionally, it has been assumed that sperm are a vehicle for genes and nothing more. As such, the only source of variance in offspring phenotype via the paternal line has been genetic effects. More recently, however, it has been shown that the phenotype or environment of fathers can affect the phenotype of offspring, challenging traditional theory with implications for evolution, ecology and human in vitro fertilisation. Here, I review sources of non-genetic variation in the sperm phenotype and evidence for co-variation between sperm and offspring phenotypes. I distinguish between two environmental sources of variation in sperm phenotype: the pre-release environment and the post-release environment. Pre-release, sperm phenotypes can vary within species according to male phenotype (e.g. body size) and according to local conditions such as the threat of sperm competition. Post-release, the physicochemical conditions that sperm experience, either when freely spawned or when released into the female reproductive tract, can further filter or modify sperm phenotypes. I find evidence that both pre- and post-release sperm environments can affect offspring phenotype; fertilisation is not a new beginning – rather, the experiences of sperm with the father and upon release can drive variation in the phenotype of the offspring. Interestingly, there was some evidence for co-variation between the stress resistance of sperm and the stress resistance of offspring, though more studies are needed to determine whether such effects are widespread. Overall, it appears that environmentally induced covariation between sperm and offspring phenotypes is non-negligible and further work is needed to determine their prevalence and strength. © 2015. Published by The Company of Biologists Ltd.

Results from the latest SN-4 multi-parametric benthic observatory experiment (MARsite EU project) in the Gulf of Izmit, Turkey: oceanographic, chemical and seismic monitoring

NASA Astrophysics Data System (ADS)

Embriaco, Davide; Marinaro, Giuditta; Frugoni, Francesco; Giovanetti, Gabriele; Monna, Stephen; Etiope, Giuseppe; Gasperini, Luca; Çağatay, Namık; Favali, Paolo

2015-04-01

An autonomous and long-term multiparametric benthic observatory (SN-4) was designed to study gas seepage and seismic energy release along the submerged segment of the North Anatolian Fault (NAF). Episodic gas seepage occurs at the seafloor in the Gulf of Izmit (Sea of Marmara, NW Turkey) along this submerged segment of the NAF, which ruptured during the 1999 Mw7.4 Izmit earthquake. The SN-4 observatory already operated in the Gulf of Izmit at the western end of the 1999 Izmit earthquake rupture for about one-year at 166 m water depth during the 2009-2010 experiment (EGU2014-13412-1, EGU General Assembly 2014). SN-4 was re-deployed in the same site for a new long term mission (September 2013 - April 2014) in the framework of MARsite (New Directions in Seismic Hazard assessment through Focused Earth Observation in the Marmara Supersite, http://marsite.eu/ ) EC project, which aims at evaluating seismic risk and managing of long-term monitoring activities in the Marmara Sea. A main scientific objective of the SN-4 experiment is to investigate the possible correlations between seafloor methane seepage and release of seismic energy. We used the same site of the 2009-2010 campaign to verify both the occurrence of previously observed phenomena and the reliability of results obtained in the previous experiment (Embriaco et al., 2014, doi:10.1093/gji/ggt436). In particular, we are interested in the detection of gas release at the seafloor, in the role played by oceanographic phenomena in this detection, and in the association of gas and seismic energy release. The scientific payload included, among other instruments, a three-component broad-band seismometer, and gas and oceanographic sensors. We present a technical description of the observatory, including the data acquisition and control system, results from the preliminary analysis of this new multidisciplinary data set, and a comparison with the previous experiment.

Examination of Rapid Dopamine Dynamics with Fast Scan Cyclic Voltammetry During Intra-oral Tastant Administration in Awake Rats.

PubMed

Wickham, Robert J; Park, Jinwoo; Nunes, Eric J; Addy, Nii A

2015-08-12

Rapid, phasic dopamine (DA) release in the mammalian brain plays a critical role in reward processing, reinforcement learning, and motivational control. Fast scan cyclic voltammetry (FSCV) is an electrochemical technique with high spatial and temporal (sub-second) resolution that has been utilized to examine phasic DA release in several types of preparations. In vitro experiments in single-cells and brain slices and in vivo experiments in anesthetized rodents have been used to identify mechanisms that mediate dopamine release and uptake under normal conditions and in disease models. Over the last 20 years, in vivo FSCV experiments in awake, freely moving rodents have also provided insight of dopaminergic mechanisms in reward processing and reward learning. One major advantage of the awake, freely moving preparation is the ability to examine rapid DA fluctuations that are time-locked to specific behavioral events or to reward or cue presentation. However, one limitation of combined behavior and voltammetry experiments is the difficulty of dissociating DA effects that are specific to primary rewarding or aversive stimuli from co-occurring DA fluctuations that mediate reward-directed or other motor behaviors. Here, we describe a combined method using in vivo FSCV and intra-oral infusion in an awake rat to directly investigate DA responses to oral tastants. In these experiments, oral tastants are infused directly to the palate of the rat--bypassing reward-directed behavior and voluntary drinking behavior--allowing for direct examination of DA responses to tastant stimuli.

The "trapped fraction" and interfacial jumps of concentration in fission products release from coated fuel particles

NASA Astrophysics Data System (ADS)

Ivanov, A. S.; Rusinkevich, A. A.; Taran, M. D.

2018-01-01

The FP Kinetics computer code [1] designed for calculation of fission products release from HTGR coated fuel particles was modified to allow consideration of chemical bonding, effects of limited solubility and component concentration jumps at interfaces between coating layers. Curves of Cs release from coated particles calculated with the FP Kinetics and PARFUME [2] codes were compared. It has been found that the consideration of concentration jumps at silicon carbide layer interfaces allows giving an explanation of some experimental data on Cs release obtained from post-irradiation heating tests. The need to perform experiments for measurement of solubility limits in coating materials was noted.

Demonstration of Technologies for Remote and in Situ Sensing of Atmospheric Methane Abundances - a Controlled Release Experiment

NASA Astrophysics Data System (ADS)

Aubrey, A. D.; Thorpe, A. K.; Christensen, L. E.; Dinardo, S.; Frankenberg, C.; Rahn, T. A.; Dubey, M.

2013-12-01

It is critical to constrain both natural and anthropogenic sources of methane to better predict the impact on global climate change. Critical technologies for this assessment include those that can detect methane point and concentrated diffuse sources over large spatial scales. Airborne spectrometers can potentially fill this gap for large scale remote sensing of methane while in situ sensors, both ground-based and mounted on aerial platforms, can monitor and quantify at small to medium spatial scales. The Jet Propulsion Laboratory (JPL) and collaborators recently conducted a field test located near Casper, WY, at the Rocky Mountain Oilfield Test Center (RMOTC). These tests were focused on demonstrating the performance of remote and in situ sensors for quantification of point-sourced methane. A series of three controlled release points were setup at RMOTC and over the course of six experiment days, the point source flux rates were varied from 50 LPM to 2400 LPM (liters per minute). During these releases, in situ sensors measured real-time methane concentration from field towers (downwind from the release point) and using a small Unmanned Aerial System (sUAS) to characterize spatiotemporal variability of the plume structure. Concurrent with these methane point source controlled releases, airborne sensor overflights were conducted using three aircraft. The NASA Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) participated with a payload consisting of a Fourier Transform Spectrometer (FTS) and an in situ methane sensor. Two imaging spectrometers provided assessment of optical and thermal infrared detection of methane plumes. The AVIRIS-next generation (AVIRIS-ng) sensor has been demonstrated for detection of atmospheric methane in the short wave infrared region, specifically using the absorption features at ~2.3 μm. Detection of methane in the thermal infrared region was evaluated by flying the Hyperspectral Thermal Emission Spectrometer (HyTES), retrievals which interrogate spectral features in the 7.5 to 8.5 μm region. Here we discuss preliminary results from the JPL activities during the RMOTC controlled release experiment, including capabilities of airborne sensors for total columnar atmospheric methane detection and comparison to results from ground measurements and dispersion models. Potential application areas for these remote sensing technologies include assessment of anthropogenic and natural methane sources over wide spatial scales that represent significant unconstrained factors to the global methane budget.

The WCRP/GEWEX Surface Radiation Budget Project Release 2: An Assessment of Surface Fluxes at 1 Degree Resolution

NASA Technical Reports Server (NTRS)

Stackhouse, P. W., Jr.; Gupta, S. K.; Cox, S. J.; Chiacchio, M.; Mikovitz, J. C.

2004-01-01

The U.S. National Aeronautics and Space Administration (NASA) based Surface Radiation Budget (SRB) Project in association with the World Climate Research Programme Global Energy and Water Cycle Experiment (WCRP/GEWEX) is preparing a new 1 deg x 1 deg horizontal resolution product for distribution scheduled for release in early 2001. The new release contains several significant upgrades from the previous version. This paper summarizes the most significant upgrades and presents validation results as an assessment of the new data set.

In vitro release of cupric ion from intrauterine devices: influence of frame, shape, copper surface area and indomethacin.

PubMed

Zhang, Shuangshuang; Li, Ying; Yu, Panpan; Chen, Tong; Zhou, Weisai; Zhang, Wenli; Liu, Jianping

2015-02-01

The release of cupric ion from copper intrauterine device (Cu-IUD) in human uterus is essential for contraception. However, excessive cupric ion will cause cytotoxic effect. In this paper, we investigated the influence of device characteristics (frame, copper surface area, shape, copper type and indomethacin) on copper release for the efficacy and adverse effects vary with IUD types which may correlate to their different release behaviors. Nine types of Cu-IUDs were selected and incubated in simulated uterine fluid. They were paired for comparison based on the device properties and the release of cupric ion was determined by flame atomic absorption spectrometer for about 160 days. The result showed that there was a burst release during the first month and the release rate tends to slow down and become steady afterwards. In addition, the copper release was mainly influenced by frame, indomethacin and copper type (copper wire and copper sleeve) while the shape variation had little effect on copper release throughout the experiment. Moreover, the influence of copper surface area was only noticeable during the first month. These findings were seldom reported before and may provide some useful information for the design of Cu-IUDs.

A self-referential HOWTO on release engineering

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

Galassi, Mark C.

Release engineering is a fundamental part of the software development cycle: it is the point at which quality control is exercised and bug fixes are integrated. The way in which software is released also gives the end user her first experience of a software package, while in scientific computing release engineering can guarantee reproducibility. For these reasons and others, the release process is a good indicator of the maturity and organization of a development team. Software teams often do not put in place a release process at the beginning. This is unfortunate because the team does not have early andmore » continuous execution of test suites, and it does not exercise the software in the same conditions as the end users. I describe an approach to release engineering based on the software tools developed and used by the GNU project, together with several specific proposals related to packaging and distribution. I do this in a step-by-step manner, demonstrating how this very paper is written and built using proper release engineering methods. Because many aspects of release engineering are not exercised in the building of the paper, the accompanying software repository also contains examples of software libraries.« less

Pulsed magnetic field induced fast drug release from magneto liposomes via ultrasound generation.

PubMed

Podaru, George; Ogden, Saralyn; Baxter, Amanda; Shrestha, Tej; Ren, Shenqiang; Thapa, Prem; Dani, Raj Kumar; Wang, Hongwang; Basel, Matthew T; Prakash, Punit; Bossmann, Stefan H; Chikan, Viktor

2014-10-09

Fast drug delivery is very important to utilize drug molecules that are short-lived under physiological conditions. Techniques that can release model molecules under physiological conditions could play an important role to discover the pharmacokinetics of short-lived substances in the body. Here an experimental method is developed for the fast release of the liposomes' payload without a significant increase in (local) temperatures. This goal is achieved by using short magnetic pulses to disrupt the lipid bilayer of liposomes loaded with magnetic nanoparticles. The drug release has been tested by two independent assays. The first assay relies on the AC impedance measurements of MgSO4 released from the magnetic liposomes. The second standard release assay is based on the increase of the fluorescence signal from 5(6)-carboxyfluorescein dye when the dye is released from the magneto liposomes. The efficiency of drug release ranges from a few percent to up to 40% in the case of the MgSO4. The experiments also indicate that the magnetic nanoparticles generate ultrasound, which is assumed to have a role in the release of the model drugs from the magneto liposomes.

Shock compression modeling of metallic single crystals: comparison of finite difference, steady wave, and analytical solutions

DOE PAGES

Lloyd, Jeffrey T.; Clayton, John D.; Austin, Ryan A.; ...

2015-07-10

Background: The shock response of metallic single crystals can be captured using a micro-mechanical description of the thermoelastic-viscoplastic material response; however, using a such a description within the context of traditional numerical methods may introduce a physical artifacts. Advantages and disadvantages of complex material descriptions, in particular the viscoplastic response, must be framed within approximations introduced by numerical methods. Methods: Three methods of modeling the shock response of metallic single crystals are summarized: finite difference simulations, steady wave simulations, and algebraic solutions of the Rankine-Hugoniot jump conditions. For the former two numerical techniques, a dislocation density based framework describes themore » rate- and temperature-dependent shear strength on each slip system. For the latter analytical technique, a simple (two-parameter) rate- and temperature-independent linear hardening description is necessarily invoked to enable simultaneous solution of the governing equations. For all models, the same nonlinear thermoelastic energy potential incorporating elastic constants of up to order 3 is applied. Results: Solutions are compared for plate impact of highly symmetric orientations (all three methods) and low symmetry orientations (numerical methods only) of aluminum single crystals shocked to 5 GPa (weak shock regime) and 25 GPa (overdriven regime). Conclusions: For weak shocks, results of the two numerical methods are very similar, regardless of crystallographic orientation. For strong shocks, artificial viscosity affects the finite difference solution, and effects of transverse waves for the lower symmetry orientations not captured by the steady wave method become important. The analytical solution, which can only be applied to highly symmetric orientations, provides reasonable accuracy with regards to prediction of most variables in the final shocked state but, by construction, does not provide insight into the shock structure afforded by the numerical methods.« less

Explosion bomb measurements of ethanol-air laminar gaseous flame characteristics at pressures up to 1.4 MPa

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

Bradley, D.; Lawes, M.; Mansour, M.S.

2009-07-15

The principal burning characteristics of a laminar flame comprise the fuel vapour pressure, the laminar burning velocity, ignition delay times, Markstein numbers for strain rate and curvature, the stretch rates for the onset of flame instabilities and of flame extinction for different mixtures. With the exception of ignition delay times, measurements of these are reported and discussed for ethanol-air mixtures. The measurements were in a spherical explosion bomb, with central ignition, in the regime of a developed stable, flame between that of an under or over-driven ignition and that of an unstable flame. Pressures ranged from 0.1 to 1.4 MPa,more » temperatures from 300 to 393 K, and equivalence ratios were between 0.7 and 1.5. It was important to ensure the relatively large volume of ethanol in rich mixtures at high pressures was fully evaporated. The maximum pressure for the measurements was the highest compatible with the maximum safe working pressure of the bomb. Many of the flames soon became unstable, due to Darrieus-Landau and thermo-diffusive instabilities. This effect increased with pressure and the flame wrinkling arising from the instabilities enhanced the flame speed. Both the critical Peclet number and the, more rational, associated critical Karlovitz stretch factor were evaluated at the onset of the instability. With increasing pressure, the onset of flame instability occurred earlier. The measured values of burning velocity are expressed in terms of their variations with temperature and pressure, and these are compared with those obtained by other researchers. Some comparisons are made with the corresponding properties for iso-octane-air mixtures. (author)« less

Factors affecting the presence of dissolved glutathione in estuarine waters.

PubMed

Tang, Degui; Shafer, Martin M; Karner, Dawn A; Overdier, Joel; Armstrong, David E

2004-08-15

We investigated factors influencing the presence of the thiol glutathione (GSH) in estuarine waters. Our study addressed thiol phase-association, the biological release from algal cultures, and the role of copper in both thiol release and preservation. Our measurements in three diverse estuaries in the continental United States (San Diego Bay, Cape Fear Estuary, and Norfolk Estuary) show that dissolved GSH, present at sub-nanomolar levels, is preferentially partitioned into the ultra-filtrate fraction (<1 kDa) in comparison with dissolved organic carbon (DOC). Concentrations of GSH generally increased with increases in total copper (Cu)levels, although large variability was observed among estuaries. In 30-h exposure experiments, release of dissolved GSH from the diatom Thalassiosira weissflogii into organic ligand-free experimental media was a strong function of added Cu concentration. The released GSH increased from about 0.02 to 0.27 fmol/cell as Cu was increased from the background level (0.5 nM) to 310 nM in the modified Aquil media. However, excretion of GSH was lower (up to 0.13 fmol/cell) when cells were grown in surface waters of San Diego Bay, despite much higher total Cu concentrations. Experiments conducted in-situ in San Diego Bay water indicated that high concentrations of added Cu destabilized GSH, while both Mn(II) and natural colloids promoted GSH stability. In contrast, laboratory experiments in synthetic media indicated that moderate levels of added Cu enhanced GSH stability.

Magnetic molecularly imprinted polymer for aspirin recognition and controlled release

NASA Astrophysics Data System (ADS)

Kan, Xianwen; Geng, Zhirong; Zhao, Yao; Wang, Zhilin; Zhu, Jun-Jie

2009-04-01

Core-shell structural magnetic molecularly imprinted polymers (magnetic MIPs) with combined properties of molecular recognition and controlled release were prepared and characterized. Magnetic MIPs were synthesized by the co-polymerization of methacrylic acid (MAA) and trimethylolpropane trimethacrylate (TRIM) around aspirin (ASP) at the surface of double-bond-functionalized Fe3O4 nanoparticles in chloroform. The obtained spherical magnetic MIPs with diameters of about 500 nm had obvious superparamagnetism and could be separated quickly by an external magnetic field. Binding experiments were carried out to evaluate the properties of magnetic MIPs and magnetic non-molecularly imprinted polymers (magnetic NIPs). The results demonstrated that the magnetic MIPs had high adsorption capacity and selectivity to ASP. Moreover, release profiles and release rate of ASP from the ASP-loaded magnetic MIPs indicated that the magnetic MIPs also had potential applications in drug controlled release.

Effects of multiple antibiotics exposure on denitrification process in the Yangtze Estuary sediments.

PubMed

Yin, Guoyu; Hou, Lijun; Liu, Min; Zheng, Yanling; Li, Xiaofei; Lin, Xianbiao; Gao, Juan; Jiang, Xiaofen; Wang, Rong; Yu, Chendi

2017-03-01

Denitrification is a dominant reactive nitrogen removal pathway in most estuarine and coastal ecosystems, and plays a significant role in regulating N 2 O release. Although multiple antibiotics residues are widely detected in aquatic environment, combined effects of antibiotics on denitrification remain indistinct. In this work, 5 classes of antibiotics (sulfonamides, chloramphenicols, tetracyclines, macrolides, and fluoroquinolones) were selected to conduct orthogonal experiments in order to explore their combined effects on denitrification. 15 N-based denitrification and N 2 O release rates were determined in the orthogonal experiments, while denitrifying functional genes were examined to illustrate the microbial mechanism of the combined antibiotics effect. Denitrification rates were inhibited by antibiotics treatments, and synergistic inhibition effect was observed for multiple antibiotics exposure. Different classes of antibiotics had different influence on N 2 O release rates, but multiple antibiotics exposure mostly led to stimulatory effect. Abundances of denitrifying functional genes were inhibited by multiple antibiotics exposure due to the antimicrobial properties, and different inhibition on denitrifiers may be the major mechanism for the variations of N 2 O release rates. Combined effects of antibiotics on denitrification may lead to nitrate retention and N 2 O release in estuarine and coastal ecosystems, and consequently cause cascading environmental problems, such as greenhouse effects and hyper-eutrophication. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Sustainable Release of Vancomycin and Its Degradation Products From Nanostructured Collagen/Hydroxyapatite Composite Layers.

PubMed

Suchý, Tomáš; Šupová, Monika; Klapková, Eva; Horný, Lukáš; Rýglová, Šárka; Žaloudková, Margit; Braun, Martin; Sucharda, Zbyněk; Ballay, Rastislav; Veselý, Jan; Chlup, Hynek; Denk, František

2016-03-01

Infections of the musculoskeletal system present a serious problem with regard to the field of orthopedic and trauma medicine. The aim of the experiment described in this study was to develop a resorbable nanostructured composite layer with the controlled elution of antibiotics. The layer is composed of collagen, hydroxyapatite nanoparticles, and vancomycin hydrochloride (10 wt%). The stability of the collagen was enhanced by means of cross-linking. Four cross-linking agents were studied, namely an ethanol solution, a phosphate buffer solution of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide, genipin, and nordihydroguaiaretic acid. High performance liquid chromatography was used so as to characterize the in vitro release rates of the vancomycin and its crystalline degradation antibiotically inactive products over a 21-day period. The maximum concentration of the released active form of vancomycin (approximately 265 mg/L) exceeded the minimum inhibitory concentration up to an order of 17 times without triggering the burst releasing effect. At the end of the experiment, the minimum inhibitory concentration was exceeded by up to 6 times (approximately 100 mg/L). It was determined that the modification of collagen with hydroxyapatite nanoparticles does not negatively influence the sustainable release of vancomycin. The balance of vancomycin and its degradation products was observed after 14 days of incubation. Copyright © 2016. Published by Elsevier Inc.

Effective control of modified palygorskite to NH4+-N release from sediment.

PubMed

Chen, Lei; Zheng, Tianyuan; Zhang, Junjie; Liu, Jie; Zheng, Xilai

2014-01-01

Sediment capping is an in situ treatment technology that can effectively restrain nutrient and pollutant release from the sediment in lakes and reservoirs. Research on sediment capping has focused on the search for effective, non-polluting and affordable capping materials. The efficiency and mechanism of sediment capping with modified palygorskite in preventing sediment ammonia nitrogen (NH4+-N) release to surface water were investigated through a series of batch and sediment capping experiments. Purified palygorskite and different types of modified palygorskite (i.e. heated, acid-modified and NaCI-modified palygorskite) were used in this investigation. Factors affecting control efficiency, including the temperature, thickness and grain size of the capping layer, were also analysed. The batch tests showed that the adsorption of NH4+-N on modified palygorskite achieved an equilibration in the initial 45 min, and the adsorption isotherm followed the Freundlich equation. Sediment capping experiments showed that compared with non-capped condition, covering the sediment with modified palygorskite and sand both inhibited NH4+-N release to the overlying water. Given its excellent chemical stability and strong adsorption, heated palygorskite, which has a NH4+-N release inhibition ratio of 41.3%, is a more effective sediment capping material compared with sand. The controlling effectiveness of the modified palygorskite increases with thicker capping layer, lower temperature and smaller grain size of the capping material.

Characterization of a mine fire using atmospheric monitoring system sensor data.

PubMed

Yuan, L; Thomas, R A; Zhou, L

2017-06-01

Atmospheric monitoring systems (AMS) have been widely used in underground coal mines in the United States for the detection of fire in the belt entry and the monitoring of other ventilation-related parameters such as airflow velocity and methane concentration in specific mine locations. In addition to an AMS being able to detect a mine fire, the AMS data have the potential to provide fire characteristic information such as fire growth - in terms of heat release rate - and exact fire location. Such information is critical in making decisions regarding fire-fighting strategies, underground personnel evacuation and optimal escape routes. In this study, a methodology was developed to calculate the fire heat release rate using AMS sensor data for carbon monoxide concentration, carbon dioxide concentration and airflow velocity based on the theory of heat and species transfer in ventilation airflow. Full-scale mine fire experiments were then conducted in the Pittsburgh Mining Research Division's Safety Research Coal Mine using an AMS with different fire sources. Sensor data collected from the experiments were used to calculate the heat release rates of the fires using this methodology. The calculated heat release rate was compared with the value determined from the mass loss rate of the combustible material using a digital load cell. The experimental results show that the heat release rate of a mine fire can be calculated using AMS sensor data with reasonable accuracy.

The Latest SORCE Solar Spectral Irradiance Data Release: Inter-Comparison and a First Look at TSIS SIM Measurement.

NASA Astrophysics Data System (ADS)

Beland, S.; Sandoval, L.; Vanier, B.; Elliott, J.; Harder, J. W.; Snow, M. A.; Woods, T. N.; Richard, E. C.; Pilewskie, P.

2017-12-01

The Spectral Irradiance Monitor (SIM), the SOLar STellar Irradiance Comparison Experiment (SOLSTICE), and the XUV Photometer System (XPS) instruments on board the Solar Radiation and Climate Experiment (SORCE) mission have been taking daily Solar spectral irradiance (SSI) measurements since April 2003. We present the latest data releases from these instruments, describing the improvements in the new datasets and the trends measured during Solar cycles 23 and 24. An inter-comparison of the SSI over the overlapping wavelengths for SIM and SOLSTICE is presented as well as, if the data is available, a comparison with the first light measurements from TSIS-SIM.

Mobility and persistence of methane in groundwater in a controlled-release field experiment

NASA Astrophysics Data System (ADS)

Cahill, Aaron G.; Steelman, Colby M.; Forde, Olenka; Kuloyo, Olukayode; Emil Ruff, S.; Mayer, Bernhard; Ulrich Mayer, K.; Strous, Marc; Cathryn Ryan, M.; Cherry, John A.; Parker, Beth L.

2017-03-01

Expansion of shale gas extraction has fuelled global concern about the potential impact of fugitive methane on groundwater and climate. Although methane leakage from wells is well documented, the consequences on groundwater remain sparsely studied and are thought by some to be minor. Here we present the results of a 72-day methane gas injection experiment into a shallow, flat-lying sand aquifer. In our experiment, although a significant fraction of methane vented to the atmosphere, an equal portion remained in the groundwater. We find that methane migration in the aquifer was governed by subtle grain-scale bedding that impeded buoyant free-phase gas flow and led to episodic releases of free-phase gas. The result was lateral migration of gas beyond that expected by groundwater advection alone. Methane persisted in the groundwater zone despite active growth of methanotrophic bacteria, although much of the methane that vented into the vadose zone was oxidized. Our findings demonstrate that even small-volume releases of methane gas can cause extensive and persistent free phase and solute plumes emanating from leaks that are detectable only by contaminant hydrogeology monitoring at high resolution.

Streamlined Approach for Environmental Restoration (SAFER) Plan for Corrective Action Unit 415: Project 57 No. 1 Plutonium Dispersion (NTTR), Nevada, Revision 0

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

Matthews, Patrick; Burmeister, Mark

2014-04-01

This Streamlined Approach for Environmental Restoration (SAFER) Plan addresses the actions needed to achieve closure for Corrective Action Unit (CAU) 415, Project 57 No. 1 Plutonium Dispersion (NTTR). CAU 415 is located on Range 4808A of the Nevada Test and Training Range (NTTR) and consists of one corrective action site: NAFR-23-02, Pu Contaminated Soil. The CAU 415 site consists of the atmospheric release of radiological contaminants to surface soil from the Project 57 safety experiment conducted in 1957. The safety experiment released plutonium (Pu), uranium (U), and americium (Am) to the surface soil over an area of approximately 1.9 squaremore » miles. This area is currently fenced and posted as a radiological contamination area. Vehicles and debris contaminated by the experiment were subsequently buried in a disposal trench within the surface-contaminated, fenced area and are assumed to have released radiological contamination to subsurface soils. Potential source materials in the form of pole-mounted electrical transformers were also identified at the site and will be removed as part of closure activities.« less

Physical and chemical processes of sulphur dioxide in the plume from an oil-fired power station.

PubMed

Flyger, H; Lewin, E; Thomsen, E L; Fenger, J; Lyck, E; Gryning, S E

1977-03-01

The Danish contribution to the EUROCOP COST 61a project is described. Work concerned the physical and chemical reactions of sulphur dioxide released from a power station. The investigation was based on the application of two tracers. Inactive, inert SF6 is used to monitor the dispersion of and deposition from the plume; it was intended to use radioactive 35SO2 to determine the degree of oxidation of sulphur released from the stack; so far, however, public reaction has prevented the use of a release of activity in field experiments. The report describes the construction and testing of airborne instruments for continuous registration of sulphur dioxide, nitrogen oxides, ozone and the tracer SF6, as well as for measurements of temperature and humidity. Sulphur samples were collected on filter paper in a specially constructed low volume air sampler, and the subsequentchemical analysis in the laboratory is described. Finally, the problem of navigation is treated. It is shown that nitrogen oxides may be used as an internal tracer in plume experiments. Preliminary experiments based on inactive analysis only indicated an overall half-life for SO2 in the plume of about half an hour.

A mark-release-recapture experiment with Anopheles sinensis in the northern part of Gyeonggi-do, Korea.

PubMed

Cho, Shin-Hyeong; Lee, Hyeong-Woo; Shin, E-Hyun; Lee, Hee-Il; Lee, Wook-Gyo; Kim, Chong-Han; Kim, Jong-Taek; Lee, Jong-Soo; Lee, Won-Ja; Jung, Gi-Gon; Kim, Tong-Soo

2002-09-01

In order to study the range of flight and feeding activity of Anopheles sinensis, the dispersal experiment was conducted in Paju city, located in the northern part of Gyeonggi-do, Republic of Korea, during the period of 7th to 28th September 1998. Unfed females An. sinensis were collected in cowshed and released after being marked with fluorescent dye at 23:00 hours on the same day. Released female mosquitoes were recaptured everyday during 21 days using light traps, which were set at 10 sites in the cowsheds located 1, 3, 6, 9 and 12 km north-northwest and north-northeast and at 3 sites located 1, 6 and 9 km toward south-west from the release point. In addition, to study the longest flight distance in one night, we set the light traps at 16 and 20 km toward north-northeast from the release site. All the collected mosquitoes were placed on filter papers and observed on UV transilluminator after treatment with one drop of 100% ethanol. Out of 12,773 females of An. sinensis released, 194 marked females mosquitoes were recaptured, giving 1.52% recapture rate. Of 194, 72 mosquitoes (37.1%) were recaptured in light traps from three places set at 1 km from the release point, 57 mosquitoes (29.4%) from two places at 1-3 km, 41 mosquitoes (21.1%) from three places at 3-6 km, 20 mosquitoes (10.3%) from three places at 6-9 km, and 4 mosquitoes (2.1%) from two places at 9-12 km. Since 170 female mosquitoes (87.6%) out of 194 marked mosquitoes were captured within 6 km from the release point, this flight radius represents the main activity area. An sinensis was found to be able to fly at least 12 km during one night.

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

Mehl, M; Kukkadapu, G; Kumar, K

The use of gasoline in homogeneous charge compression ignition engines (HCCI) and in duel fuel diesel - gasoline engines, has increased the need to understand its compression ignition processes under engine-like conditions. These processes need to be studied under well-controlled conditions in order to quantify low temperature heat release and to provide fundamental validation data for chemical kinetic models. With this in mind, an experimental campaign has been undertaken in a rapid compression machine (RCM) to measure the ignition of gasoline mixtures over a wide range of compression temperatures and for different compression pressures. By measuring the pressure history duringmore » ignition, information on the first stage ignition (when observed) and second stage ignition are captured along with information on the phasing of the heat release. Heat release processes during ignition are important because gasoline is known to exhibit low temperature heat release, intermediate temperature heat release and high temperature heat release. In an HCCI engine, the occurrence of low-temperature and intermediate-temperature heat release can be exploited to obtain higher load operation and has become a topic of much interest for engine researchers. Consequently, it is important to understand these processes under well-controlled conditions. A four-component gasoline surrogate model (including n-heptane, iso-octane, toluene, and 2-pentene) has been developed to simulate real gasolines. An appropriate surrogate mixture of the four components has been developed to simulate the specific gasoline used in the RCM experiments. This chemical kinetic surrogate model was then used to simulate the RCM experimental results for real gasoline. The experimental and modeling results covered ultra-lean to stoichiometric mixtures, compressed temperatures of 640-950 K, and compression pressures of 20 and 40 bar. The agreement between the experiments and model is encouraging in terms of first-stage (when observed) and second-stage ignition delay times and of heat release rate. The experimental and computational results are used to gain insight into low and intermediate temperature processes during gasoline ignition.« less

Effects of post-capture ventilation assistance and elevated water temperature on sockeye salmon in a simulated capture-and-release experiment

PubMed Central

Robinson, Kendra A.; Hinch, Scott G.; Gale, Marika K.; Clark, Timothy D.; Wilson, Samantha M.; Donaldson, Michael R.; Farrell, Anthony P.; Cooke, Steven J.; Patterson, David A.

2013-01-01

The live release of wild adult Pacific salmon (Oncorhynchus spp.) following capture is a management tactic often used in commercial, aboriginal, and recreational fisheries. Fisheries capture and handling can be both exhausting and stressful to fish, which can limit their ability to swim and survive after release. As a result, researchers have assessed methods intended to improve post-release survival by assisting the flow of water over the gills of fish prior to release. Such approaches use recovery bags or boxes that direct water over the gills of restrained fish. This study evaluated a method of assisting ventilation that mimics one often employed by recreational anglers (i.e. holding fish facing into a current). Under laboratory conditions, wild Fraser River sockeye salmon (Oncorhynchus nerka) either received manual ventilation assistance for 1 min using a jet of water focused at the mouth or were left to recover unassisted following a capture-and-release simulation. A control group consisted of fish that were not exposed to the simulation or ventilation assistance. The experiment was conducted at 16 and 21°C, average and peak summer water temperatures for the Fraser River, and fish survival was monitored for 33 days. At 21°C, all fish perished within 3 days after treatment in all experimental groups, highlighting the consequences of handling adult sockeye salmon during elevated migration temperatures. Survival was higher at 16°C, with fish surviving on average 15–20 days after treatment. At 16°C, the capture-and-release simulation and ventilation assistance did not affect the survival of males; however, female survival was poor after the ventilation assistance compared with the unassisted and control groups. Our results suggest that the method of ventilation assistance tested in this study may not enhance the post-release survival of adult Fraser River sockeye salmon migrating in fresh water. PMID:27293599

Professional Learning in Canada: Learning Forward Releases a Landmark Study and Call to Action

ERIC Educational Resources Information Center

Learning Professional, 2017

2017-01-01

Learning Forward recently released findings from a new study that fills a long-standing gap in existing Pan-Canadian research, identifying key components of effective professional learning based on findings from educators' experiences in Canada. Accompanying the study is a call to action by Michael Fullan and Andy Hargreaves making the case for a…

Design Project on Controlled-Release Drug Delivery Devices: Implementation, Management, and Learning Experiences

ERIC Educational Resources Information Center

Xu, Qingxing; Liang, Youyun; Tong, Yen Wah; Wang, Chi-Hwa

2010-01-01

A design project that focuses on the subject of controlled-release drug delivery devices is presented for use in an undergraduate course on mass transfer. The purpose of the project is to introduce students to the various technologies used in the fabrication of drug delivery systems and provide a practical design exercise for understanding the…

THE DISTRIBUTION OF CHLORPYRIFOSIN AIR, CARPETING, AND DUST AND ITS REEMISSION FROM CARPETING FOLLOWING THE USE OF TOTAL RELEASE AEROSOLS IN AN INDOOR AIR QUALITY TEST HOUSE

EPA Science Inventory

The paper gives results of experiments to explore the relationships between the insecticide chlorpyrifos and its distribution into carpet., carpet dust, and reemission into air. Two total release aerosols containing 0.5% chlorpyrifos were applied in the living room and den of EP...

Feeding Frequency Affects Cultured Rat Pituitary Cells in Low Gravity

NASA Technical Reports Server (NTRS)

Hymer, W. C.; Grindeland, R. E.; Salada, T.; Cenci, R.; Krishnan, K.; Mukai, C.; Nagaoka, S.

1996-01-01

In this report, we describe the results of a rat pituitary cell culture experiment done on STS-65 in which the effect of cell feeding on the release of the six anterior pituitary hormones was studied. We found complex microgravity related interactions between the frequency of cell feeding and the quantity and quality (i.e. biological activity) of some of the six hormones released in flight. Analyses of growth hormone (GH) released from cells into culture media on different mission days using gel filtration and ion exchange chromatography yielded qualitatively similar results between ground and flight samples. Lack of cell feeding resulted in extensive cell clumping in flight (but not ground) cultures. Vigorous fibroblast growth occurred in both ground and flight cultures fed 4 times. These results are interpreted within the context of autocrine and or paracrine feedback interactions. Finally the payload specialist successfully prepared a fresh trypsin solution in microgravity, detached the cells from their surface and reinserted them back into the culture chamber. These cells reattached and continued to release hormone in microgravity. In summary, this experiment shows that pituitary cells are microgravity sensitive and that coupled operations routinely associated with laboratory cel1 culture can also be accomplished in low gravity.

Deep-release of Epon 828 epoxy from the shock-driven reaction product phase

NASA Astrophysics Data System (ADS)

Lang, John; Fredenburg, Anthony; Coe, Joshua; Dattelbaum, Dana

2017-06-01

A challenge in improving equations-of-state (EOS) for polymers and their product phase is the lack of off-Hugoniot data. Here, we describe a novel experimental approach for obtaining release pathways along isentropes from the shocked products. A series of gas-gun experiments was conducted to obtain release isentropes of the products for 70/30 wt% Epon 828 epoxy resin/Jeffamine T-403 curing agent. Thin epoxy flyers backed by a low-density syntactic foam were impacted into LiF windows at up to 6.3 mm/ μs, creating stresses in excess of those required for reaction ( 25 GPa). Following a sustained shock input, a rarefaction fan from the back of the thin flyer reduced the pressure in the epoxy products along a release isentrope. Optical velocimetry (PDV) was used to measure the particle velocity at the epoxy/LiF interface. Numerical simulations using several different EOS describing the reactant-to-product transformation were conducted, and the results were compared with measured wave profiles. The best agreement with experiment was obtained using separate tabular EOS for the polymer ``reactant'' (e.g. epoxy) and product mixture, suggesting the transition to the products is irreversible.

Characterization of Polycaprolactone and Rice Husk Silica Composite (PCL-SiO2) by E-Spinning to Apply Supporter for Drug Release

NASA Astrophysics Data System (ADS)

Song, Sinae; Hilonga, Askwar; Taik Kim, Hee

2018-03-01

Polycaprolactone (PCL) is an interesting material to apply biomedical field owing to its biodegradability and biocompatibility which is suitable for a specific site with longer healing times. Blending the polymer with other materials has degradation property improved with the effective and economic method. This study was conducted to fabricate supporter based on Polycaprolactone and Rice husk silica (PCL-SiO2) by using electrospinning. Nano-porous silica in the composite was synthesized from rice husk having properties of economic, eco-friendly and high surface area. It drew to enhance the amount of drug loading in the carrier. Electrospinning technique is used to fabricate fibrous component by optimization condition obtained from previous mechanical properties experiments. Release experiment was carried out by the degree of dye absorbance at 544nm by ultraviolet–visible spectroscopy, the RhB in SiO2 alternative drug for modelling of drug release was released for 1 ~ 20 days at 37°C in phosphate buffer. Furthermore, the Mechanical property was confirmed by DSC, TGA. Morphology and degree of biodegradation were shown as SEM images and EDS.

Agronomic Effectiveness of Granulated and Powdered P-Exchanged Mg-Al LDH Relative to Struvite and MAP.

PubMed

Everaert, Maarten; Degryse, Fien; McLaughlin, Mike J; De Vos, Dirk; Smolders, Erik

2017-08-16

Layered double hydroxides (LDHs) used to recover P from wastewater have recently been proposed as new slow-release fertilizers. Here, the use of P-exchanged Mg-Al LDHs as powdered or granulated fertilizer is explored and compared with monoammonium phosphate (MAP), a fully water-soluble fertilizer, and with struvite, a recycled phosphate fertilizer with lower solubility. First, these three fertilizers were compared in a 100-day incubation experiment using P diffusion visualization and chemical analysis to assess P release from either granules or powdered fertilizer in three different soils. By the end of the incubation, 74-90% of P remained within the LDH granule, confirming a slow release. Second, a pot experiment was performed with wheat (Triticum aestivum) in an acid and a calcareous soil. The granular treatment resulted in a considerably higher P uptake for MAP compared to LDH and struvite. For the powder treatments, the P uptake was less than for granular MAP and was largely unaffected by the chemical form. The LDHs and struvite showed a lower agronomic effectiveness than granular MAP, but the benefits of their use in P recycling, potential residual value, and environmental benefits may render these slow-release fertilizers attractive.

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.

Toxic industrial chemical (TIC) source emissions modeling for pressurized liquefied gases

NASA Astrophysics Data System (ADS)

Britter, Rex; Weil, Jeffrey; Leung, Joseph; Hanna, Steven

2011-01-01

The objective of this article is to report current toxic industrial chemical (TIC) source emissions formulas appropriate for use in atmospheric comprehensive risk assessment models so as to represent state-of-the-art knowledge. The focus is on high-priority scenarios, including two-phase releases of pressurized liquefied gases such as chlorine from rail cars. The total mass released and the release duration are major parameters, as well as the velocity, thermodynamic state, and amount and droplet sizes of imbedded aerosols of the material at the exit of the rupture, which are required as inputs to the subsequent jet and dispersion modeling. Because of the many possible release scenarios that could develop, a suite of model equations has been described. These allow for gas, two-phase or liquid storage and release through ruptures of various types including sharp-edged and "pipe-like" ruptures. Model equations for jet depressurization and phase change due to flashing are available. Consideration of the importance of vessel response to a rupture is introduced. The breakup of the jet into fine droplets and their subsequent suspension and evaporation, or rainout is still a significant uncertainty in the overall modeling process. The recommended models are evaluated with data from various TIC field experiments, in particular recent experiments with pressurized liquefied gases. It is found that there is typically a factor of two error in models compared with research-grade observations of mass flow rates. However, biases are present in models' estimates of the droplet size distributions resulting from flashing releases.

Indirect coupling of phosphate release to de novo tension generation during muscle contraction.

PubMed Central

Davis, J S; Rodgers, M E

1995-01-01

A key question in muscle contraction is how tension generation is coupled to the chemistry of the actomyosin ATPase. Biochemical and mechanochemical experiments link tension generation to a change in structure associated with phosphate release. Length-jump and temperature-jump experiments, on the other hand, implicate phase 2slow, a significantly faster, markedly strain-sensitive kinetic process in tension generation. We use a laser temperature jump to probe the kinetics and mechanism of tension generation in skinned rabbit psoas fibers--an appropriate method since both phosphate release and phase 2slow are readily perturbed by temperature. Kinetics characteristic of the structural change associated with phosphate release are observed only when phosphate is added to fibers. When present, it causes a reduction in fiber tension; otherwise, no force is generated when it is perturbed. We therefore exclude this step from tension generation. The kinetics of de novo tension generation by the temperature-jump equivalent of phase 2slow appear unaffected by phosphate binding. We therefore propose that phosphate release is indirectly coupled to de novo tension generation via a steady-state flux through an irreversible step. We conclude that tension generation occurs in the absence of chemical change as the result of an entropy-driven transition between strongly bound crossbridges in the actomyosin-ADP state. The mechanism resembles the operation of a clock, with phosphate release providing the energy to tension the spring, and the irreversible step functions as the escapement mechanism, which is followed in turn by tension generation as the movement of the hands. Images Fig. 6 PMID:7479824

75 FR 61521 - NUREG/CR-7010, Cable Heat Release, Ignition, and Spread in Tray Installations During Fire...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-05

... tray configurations. The experiments conducted range from micro-scale, in which very small (5 mg... burned under a large oxygen- depletion calorimeter. Other experiments include cone calorimetry, smoke and... tray of cables underneath a bank of radiant panels. The results of the small-scale experiments are to...

Experience-Dependent Regulation of Presynaptic NMDARs Enhances Neurotransmitter Release at Neocortical Synapses

ERIC Educational Resources Information Center

Urban-Ciecko, Joanna; Wen, Jing A.; Parekh, Puja K.; Barth, Alison L.

2015-01-01

Sensory experience can selectively alter excitatory synaptic strength at neocortical synapses. The rapid increase in synaptic strength induced by selective whisker stimulation (single-row experience/SRE, where all but one row of whiskers has been removed from the mouse face) is due, at least in part, to the trafficking of AMPA receptors (AMPARs)…

Release and microbial degradation of dissolved organic matter (DOM) from the macroalgae Ulva prolifera.

PubMed

Zhang, Tao; Wang, Xuchen

2017-12-15

Release and microbial degradation of dissolved organic matter (DOM) and chromophoric dissolved organic matter (CDOM) from the macroalgae Ulva prolifera were studied in laboratory incubation experiments. The release of DOM and CDOM from Ulva prolifera was a rapid process, and hydrolysis played an important role in the initial leaching of the organic compounds from the algae. Bacterial activity enhanced the release of DOM and CDOM during degradation of the algae and utilization of the released organic compounds. It is calculated that 43±2% of the C and 63±3% of the N from Ulva prolifera's biomass were released during the 20-day incubation, and 65±3% of the released C and 87±4% of the released N were utilized by bacteria. In comparison, only 18±1% of the algae's C and 17±1% of its N were released when bacterial activities were inhibited. The fluorescence characteristics of the CDOM indicate that protein-like DOM was the major organic component released from Ulva prolifera that was highly labile and biodegradable. Bacteria played an important role in regulating the chemical composition and fluorescence characteristics of the DOM. Our study suggests that the release of DOM from Ulva prolifera provides not only major sources of organic C and N, but also important food sources to microbial communities in coastal waters. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cometary nucleus release experiments and ice physics

NASA Technical Reports Server (NTRS)

Huebner, W. F.

1976-01-01

Some physical and chemical processes involved in the evaporation and sublimation of mixtures of frozen gases are discussed. Effects of zero gravity, vacuum, and solar radiation are emphasized. Relevant experiments that can be carried out with the aid of the space shuttle are proposed.

In vitro and in vivo delivery of the secretagogue diadenosine tetraphosphate from conventional and silicone hydrogel soft contact lenses

PubMed Central

Dominguez-Godinez, Carmen Olalla; Martin-Gil, Alba; Carracedo, Gonzalo; Guzman-Aranguez, Ana; González-Méijome, José Manuel; Pintor, Jesús

2013-01-01

Purpose To evaluate the possible use of soft contact lenses (CL) to improve the secretagogue role of diadenosine tetraphosphate (Ap4A) promoting tear secretion. Methods Two conventional hydrogel CL (Omafilcon A and Ocufilcon D) and two silicone hydrogel (SiH) CL (Comfilcon A and Balafilcon A) were used. Ap4A was loaded into the lenses by soaking in a 1 mM Ap4A solution during 12 h. In vitro experiments were performed by placing the lenses in multi-wells during 2 h containing 1 ml of ultrapure water. 100 μl aliquots were taken at time zero and every minute for the first 10 min, and then every 15 min. In vivo experiments were performed in New Zealand rabbits and both the dinucleotide release from SiH and tear secretion were measured by means of Schirmer strips and high-pressure liquid chromatography (HPLC) analysis. Results Ap4A in vitro release experiments in hydrogel CL presented a release time 50 (RT50) of 3.9 ± 0.2 min and 3.1 ± 0.1 min for the non-ionic and the ionic CL, respectively. SiH CL released also Ap4A with RT50 values of 5.1 ± 0.1 min for the non-ionic and 2.7 ± 0.1 min for the ionic CL. In vivo experiments with SiH CL showed RT50 values of 9.3 ± 0.2 min and 8.5 ± 0.2 min for the non-ionic and the ionic respectively. The non-ionic lens Ap4A release was able to induce tear secretion above baseline tear levels for almost 360 min. Conclusion The delivery of Ap4A is slower and the effect lasts longer with non-ionic lenses than ionic lenses.

Dissociation of Laboratory-Synthesized Methane Hydrate in Coarse-Grained Sediments by Slow Depressurization

NASA Astrophysics Data System (ADS)

Phillips, S. C.; You, K.; Borgfeldt, T.; Meyer, D.; Dong, T.; Flemings, P. B.

2016-12-01

We performed four dissociation experiments in which experimentally-formed methane hydrate was dissociated via slow, stepwise depressurization, revealing in situ salinity conditions. Overall, these results suggest the occurrence of local pore water freshening around dissociating hydrate in which bulk equilibrium behavior is limited by salt diffusion. Depressurization was performed at a constant confining temperature over 1 to 3 weeks by releasing small volumes of methane gas from the top of a vertically-oriented sample into an inverted graduated cylinder. We identify three distinct regimes of depressurization based on pressure drop behavior: (1) release of free gas down to initial hydrate dissociation at 3.3 MPa in NaBr or 4.64 MPa in NaCl, (2) dissociation of methane hydrate characterized by a slow, logarithmic increase in pressure after each gas release and (3) residual free gas release. Initial hydrate dissociation in NaCl brine at 4.64 MPa corresponds to the phase boundary for hydrate in 9.6 wt% NaCl. In the NaCl experiment, pressure increases of 0.16 MPa while the sample was shut in over 3 days likely correspond to a recovery in salinity of 0.7 wt. %. Salt ions likely diffuse from brine ahead of the hydrate front, based on a length scale for diffusion of NaCl of 6.3 cm for 3 days. In this experiment dissociation at bulk equilibrium is expected to decline from 4.54 to 4.04 MPa; however actual dissociation during 73 gas releases over 15 days, results in a pressure drop from 4.64 to 3.25 MPa. Hydrate samples were formed by injection of methane gas at 1 ºC and 12.24 MPa within a cylinder packed with medium-grained quartz sand and initially saturated in a 7 wt% NaBr or NaCl solution. In two experiments in which the system was thoroughly leak tested, total methane consumed during formation and recovered during depressurization match within 7% indicating this approach to be relatively accurate for determining total methane in experimental or pressure core samples.

Production of reactive oxygen species from abraded silicates. Implications for the reactivity of the Martian soil

NASA Astrophysics Data System (ADS)

Bak, Ebbe N.; Zafirov, Kaloyan; Merrison, Jonathan P.; Jensen, Svend J. Knak; Nørnberg, Per; Gunnlaugsson, Haraldur P.; Finster, Kai

2017-09-01

The results of the Labeled Release and the Gas Exchange experiments conducted on Mars by the Viking Landers show that compounds in the Martian soil can cause oxidation of organics and a release of oxygen in the presence of water. Several sources have been proposed for the oxidizing compounds, but none has been validated in situ and the cause of the observed oxidation has not been resolved. In this study, laboratory simulations of saltation were conducted to examine if and under which conditions wind abrasion of silicates, a process that is common on the Martian surface, can give rise to oxidants in the form of hydrogen peroxide (H2O2) and hydroxyl radicals (ṡOH). We found that silicate samples abraded in simulated Martian atmospheres gave rise to a significant production of H2O2 and ṡOH upon contact with water. Our experiments demonstrated that abraded silicates could lead to a production of H2O2 facilitated by atmospheric O2 and inhibited by carbon dioxide. Furthermore, during simulated saltation the silicate particles became triboelectrically charged and at pressures similar to the Martian surface pressure we observed glow discharges. Electrical discharges can cause dissociation of CO2 and through subsequent reactions lead to a production of H2O2. These results indicate that the reactions linked to electrical discharges are the dominant source of H2O2 during saltation of silicates in a simulated Martian atmosphere, given the low pressure and the relatively high concentration of CO2. Our experiments provide evidence that wind driven abrasion could enhance the reactivity of the Martian soil and thereby could have contributed to the oxidation of organic compounds and the O2 release observed in the Labeled Release and the Gas Exchange experiments. Furthermore, the release of H2O2 and ṡOH from abraded silicates could have a negative effect on the persistence of organic compounds in the Martian soil and the habitability of the Martian surface.

Masking release due to linguistic and phonetic dissimilarity between the target and masker speech

PubMed Central

Calandruccio, Lauren; Brouwer, Susanne; Van Engen, Kristin J.; Dhar, Sumitrajit; Bradlow, Ann R.

2013-01-01

Purpose To investigate masking release for speech maskers for linguistically and phonetically close (English and Dutch) and distant (English and Mandarin) language pairs. Method Twenty monolingual speakers of English with normal-audiometric thresholds participated. Data are reported for an English sentence recognition task in English, Dutch and Mandarin competing speech maskers (Experiment I) and noise maskers (Experiment II) that were matched either to the long-term-average-speech spectra or to the temporal modulations of the speech maskers from Experiment I. Results Results indicated that listener performance increased as the target-to-masker linguistic distance increased (English-in-English < English-in-Dutch < English-in-Mandarin). Conclusions Spectral differences between maskers can account for some, but not all, of the variation in performance between maskers; however, temporal differences did not seem to play a significant role. PMID:23800811

The emerging understanding of magnetic reconnection through laboratory experiments, theory and modeling and in situ satellite measurements

NASA Astrophysics Data System (ADS)

Drake, James F.

2015-08-01

Magnetic reconnection is the driver of explosive energy release in laboratory, space and astrophysical plasma systems. It plays a centralrole in such diverse phenomena as solar and stellar flares, flares in pulsar nebulae, gamma ray bursts and possibly even in the productionof energetic particles in supernova shocks. The close interaction of scientists doing laboratory experiments, in situ satellite measurements and theory and modeling has led to remarkable progress on key issues such as the mechanisms for fast energy release and heating and particle acceleration. There are, however, many open issues. The talk will address the emerging understanding of reconnection as well as areas where significant uncertainty remains. The role of new laboratory experiments such as FLARE at PPPL and the recently launched four-spacecraft MMS mission in resolving open issues will be discussed.

Effect of catch-and-release angling on growth and survival of rainbow trout, Oncorhynchus mykiss

USGS Publications Warehouse

Pope, K.L.; Wilde, G.R.; Knabe, D.W.

2007-01-01

Catch-and-release angling is popular in many parts of the world and plays an increasingly important role in fish conservation efforts. Although survival rates associated with catch-and-release angling are well documented for many species, sublethal effects have been less studied. An experiment was conducted to directly assess the effects of catch-and-release angling on growth and survival of rainbow trout, Oncorhynchus mykiss (Walbaum). Catch-and-release events were simulated in laboratory tanks maintained at 15-16 ??C with hooks manually placed in pre-designated locations in the mouths of the fish. There were no differences in standard length (P = 0.59) or wet weight (P = 0.81) gained between caught and uncaught fish over a 1-month angling and recovery period. Survival was 96.99 ?? 0.06% for rainbow trout caught and released, and did not vary with number (one, two or four) of captures. Thus, catch-and-release angling appears to have little effect on growth and mortality of rainbow trout hooked in the mouth. ?? 2007 The Authors. Journal compilation 2007 Blackwell Publishing Ltd.

Evaluating the patient experience after implantation of a 0.4 mg sustained release dexamethasone intracanalicular insert (Dextenza™): results of a qualitative survey

PubMed Central

Gira, Joseph P; Sampson, Reginald; Silverstein, Steven M; Walters, Thomas R; Metzinger, Jamie Lynne; Talamo, Jonathan H

2017-01-01

Purpose The purpose of this study is to evaluate the patient experience of sustained release dexamethasone intracanalicular insert (Dextenza™) following cataract surgery as part of a Phase III clinical trial program. Methods This cross-sectional, qualitative evaluation involved individual interviews lasting approximately 45 minutes. Patients from four US investigational study sites who had previously received an insert were enrolled. There were no predesignated end points; this was a qualitative survey seeking a deeper understanding of patient experience. Results Twenty-five patients were interviewed. Most patients (92%) reported the highest level of satisfaction grade with regard to overall product satisfaction. All patients described the insert as comfortable. Most patients (96%) described their overall experience with the insert as very convenient or extremely convenient. Twenty-two of 23 (96%) participants rated their experience with the insert as “very” or “extremely convenient”, compared to previous topical therapy, and 88% of patients stated that if they were to undergo cataract surgery again, they would request the insert. When asked if they would recommend the insert to family members or friends, 92% stated they would. The survey found that 84% of participants would be willing to pay more for the insert than for eye drop therapy. Conclusion The dexamethasone insert was found by patients to be highly favorable with regard to overall satisfaction, convenience, and comfort. The insert was well received and largely preferred over topical therapy alternatives following surgery. More extensive evaluation of the patient experience is warranted, and future studies should help inform design of the next generation of sustained release drug delivery systems. PMID:28331295

Do soft drinks affect metal ions release from orthodontic appliances?

PubMed

Mikulewicz, Marcin; Wołowiec, Paulina; Loster, Bartłomiej W; Chojnacka, Katarzyna

2015-01-01

The effect of orange juice and Coca Cola(®) on the release of metal ions from fixed orthodontic appliances. A continuous flow system designed for in vitro testing of orthodontic appliances was used. Orange juice/Coca Cola(®) was flowing through the system alternately with artificial saliva for 5.5 and 18.5h, respectively. The collected samples underwent a multielemental ICP-OES analysis in order to determine the metal ions release pattern in time. The total mass of ions released from the appliance into orange juice and Coca Cola(®) (respectively) during the experiment was calculated (μg): Ni (15.33; 37.75), Cr (3.604; 1.052), Fe (48.42; ≥ 156.1), Cu (57.87, 32.91), Mn (9.164; 41.16), Mo (9.999; 30.12), and Cd (0.5967; 2.173). It was found that orange juice did not intensify the release of metal ions from orthodontic appliances, whereas Coca Cola(®) caused increased release of Ni ions. Copyright © 2015 Elsevier GmbH. All rights reserved.

Constructing early warning information release system in towns enterprise clean production

NASA Astrophysics Data System (ADS)

Yuwen, Huixin; He, Xueqiu; Qian, Xinming; Yuan, Mengqi

2017-08-01

China’s industry boom has not only brought unprecedented prosperity, but also caused the gradual depletion of various resources and the worsening of the natural environment. Experts admit that China is facing serious environmental problem, but they believe that they can seek a new path to overcome it through joint efforts. Early warning information release and clean production are the important concepts in addressing the imminent crisis. Early warning information release system can monitor and forecast the risk that affects the clean production. The author drawn the experiences and lessons from developed countries, combined with China’s reality, put forward countermeasures and suggestions about constructing early warning information release system in process of Chinese town-scaled enterprises clean production.

Controlled release of functional proteins through designer self-assembling peptide nanofiber hydrogel scaffold

PubMed Central

Koutsopoulos, Sotirios; Unsworth, Larry D.; Nagai, Yusuke; Zhang, Shuguang

2009-01-01

The release kinetics for a variety of proteins of a wide range of molecular mass, hydrodynamic radii, and isoelectric points through a nanofiber hydrogel scaffold consisting of designer self-assembling peptides were studied by using single-molecule fluorescence correlation spectroscopy (FCS). In contrast to classical diffusion experiments, the single-molecule approach allowed for the direct determination of diffusion coefficients for lysozyme, trypsin inhibitor, BSA, and IgG both inside the hydrogel and after being released into the solution. The results of the FCS analyses and the calculated pristine in-gel diffusion coefficients were compared with the values obtained from the Stokes–Einstein equation, Fickian diffusion models, and the literature. The release kinetics suggested that protein diffusion through nanofiber hydrogels depended primarily on the size of the protein. Protein diffusivities decreased, with increasing hydrogel nanofiber density providing a means of controlling the release kinetics. Secondary and tertiary structure analyses and biological assays of the released proteins showed that encapsulation and release did not affect the protein conformation and functionality. Our results show that this biocompatible and injectable designer self-assembling peptide hydrogel system may be useful as a carrier for therapeutic proteins for sustained release applications. PMID:19273853

Quantification of nanoparticle release from polymer nanocomposite coatings due to environmental stressing.

PubMed

Kim, Yeon Seok; Davis, Rick; Uddin, Nasir; Nyden, Marc; Rabb, Savelas A

2016-01-01

Certain engineered nanoparticles (ENP) reduce the flammability of components used in soft furnishings (mattresses and upholstered furniture). However, because of the ENP's small size and ability to interact with biological molecules, these fire retardant ENPs may pose a health and environmental risks, if they are released sometime during the life cycle of the soft furnishing. Quantifying the released amount of these ENPs under normal end-use circumstances provides a basis for assessing their potential health and environmental impact. In this article, we report on efforts to identify suitable methodologies for quantifying the release of carbon nanofibers, carbon nanotubes, and sodium montmorillonites from coatings applied to the surfaces of barrier fabric and polyurethane foam. The ENPs released in simulated chewing and mechanical stressing experiments were collected in aqueous solution and quantified using Ultraviolet-Visible and inductively coupled plasma-optical emission spectroscopy. The microstructures of the released ENPs were characterized using scanning electron microscopy. The reported methodology and results provide important milestones to estimate the impact and toxicity of the ENP release during the life cycle of the nanocomposites. To our knowledge, this is the first study of ENP release from the soft furnishing coating, something that can be important application area for fire safety.

Simulation and parametric study of a film-coated controlled-release pharmaceutical.

PubMed

Borgquist, Per; Zackrisson, Gunnar; Nilsson, Bernt; Axelsson, Anders

2002-04-23

Pharmaceutical formulations can be designed as Multiple Unit Systems, such as Roxiam CR, studied in this work. The dose is administrated as a capsule, which contains about 100 individual pellets, which in turn contain the active drug remoxipride. Experimental data for a large number of single pellets can be obtained by studying the release using microtitre plates. This makes it possible to study the release of the individual subunits making up the total dose. A mathematical model for simulating the release of remoxipride from single film-coated pellets is presented including internal and external mass transfer hindrance apart from the most important film resistance. The model can successfully simulate the release of remoxipride from single film-coated pellets if the lag phase of the experimental data is ignored. This was shown to have a minor influence on the release rate. The use of the present model is demonstrated by a parametric study showing that the release process is film-controlled, i.e. is limited by the mass transport through the polymer coating. The model was used to fit the film thickness and the drug loading to the experimental release data. The variation in the fitted values was similar to that obtained in the experiments.

Polymer excipients enable sustained drug release in low pH from mechanically strong inorganic geopolymers.

PubMed

Jämstorp, Erik; Yarra, Tejaswi; Cai, Bing; Engqvist, Håkan; Bredenberg, Susanne; Strømme, Maria

2012-01-01

Improving acid resistance, while maintaining the excellent mechanical stability is crucial in the development of a sustained and safe oral geopolymer dosage form for highly potent opioids. In the present work, commercially available Methacrylic acid-ethyl acrylate copolymer, Polyethylene-glycol (PEG) and Alginate polymer excipients were included in dissolved or powder form in geopolymer pellets to improve the release properties of Zolpidem, herein acting as a model drug for the highly potent opioid Fentanyl. Scanning electron microscopy, compression strength tests and drug release experiments, in gastric pH 1 and intestinal pH 6.8 conditions, were performed. The polymer excipients, with an exception for PEG, reduced the drug release rate in pH 1 due to their ability to keep the pellets in shape, in combination with the introduction of an insoluble excipient, and thereby maintain a barrier towards drug diffusion and release. Neither geopolymer compression strength nor the release in pH 6.8 was considerably impaired by the incorporation of the polymer excipients. The geopolymer/polymer composites combine high mechanical strength and good release properties under both gastric and intestinal pH conditions, and are therefore promising oral dosage forms for sustained release of highly potent opioids.

Emulsion-based encapsulation and delivery of nanoparticles for the controlled release of alkalinity within the subsurface environment

NASA Astrophysics Data System (ADS)

Ramsburg, C. A.; Muller, K.; Gill, J.

2012-12-01

Many current approaches to managing groundwater contamination rely on further advances in amendment delivery in order to initiate and sustain contaminant degradation or immobilization. In fact, limited or ineffective delivery is often cited when treatment objectives are not attained. Emulsions, specifically oil-in-water emulsions, have demonstrated potential to aid delivery of remediation amendments. Emulsions also afford opportunities to control the release of active ingredients encapsulated within the droplets. Our research is currently focused on the controlled release of nanoparticle-based buffering agents using oil-in-water emulsions. This interest is motivated by the fact that chemical and biological processes employed for the remediation and stewardship of contaminated sites often necessitate control of pH during treatment and, in some cases, long thereafter. Alkalinity-release nanoparticles (e.g., CaCO3, MgO) were suspended within soybean oil and subsequently encapsulated by through the creation of oil-in-water emulsions. These oil-in-water emulsions are designed to have physical properties which are favorable for subsurface delivery (nominal properties: 1 g/mL density; 10 cP viscosity; and 1.5 μm droplet diameter). Buffer capacity titrations suggest that MgO particles are moderately more accessible within the oil phase and nearly twice as effective (on a per mass basis) at releasing alkalinity (as compared to the CaCO3 particles). Results from experiments designed to assess the release kinetics suggest that a linear driving force model is capable of describing the release process and mass transfer coefficients are constant through the reactive life of the emulsion. The release kinetics in emulsions containing MgO particles were found to be three orders of magnitude faster than those quantified for emulsions containing CaCO3. The slower release kinetics of the emulsions containing CaCO3 particles may prove beneficial when considering pH control at sites where acid fluxes are lower. The ability of emulsions to sustain alkalinity release within porous media was preliminarily examined using a series of 1-D column experiments. Emulsions were introduced for 2 pore volumes in a medium sand at Darcy velocities of approximately 0.8 cm/hr. Following the emulsion pulse, a pH 4 solution (adjusted with HCl) was introduced into the column and the effluent was monitored for pH, oil content, and droplet size distributions. All un-retained emulsion (~20% wt. was retained) was flushed from the column within approximately 2 pore volumes of terminating the emulsion pulse. The effluent pH at quasi-steady state and the reactive life of the emulsion depended on the retention characteristics, as well as the type and loading of nanoparticles employed within the emulsion. For the scenarios considered here, quasi-steady effluent pHs were observed to be between 6.5 and 10, and reactive lifetimes (i.e., the number of pore volumes for which the retained emulsion resulted in the effluent pH exceeding that of the influent) were between 15 and 100 pore volumes. These results demonstrate the ability of the emulsion to offer longer-term release and highlight the ability to tune the alkalinity release rate to match site characteristics by adjusting the emulsion content. Current research is directed toward evaluation release properties in heterogeneous aquifer cell experiments.

Active experiments using rocket-borne shaped charge barium releases. [solar-terrestrial magnetospheric physics

NASA Technical Reports Server (NTRS)

Wescott, E. M.; Davis, T. N.

1980-01-01

A reliable payload system and scaled down shaped charges were developed for carrying out experiments in solar-terrestrial magnetospheric physics. Four Nike-Tomahawk flights with apogees near 450 km were conducted to investigate magnetospheric electric fields, and two Taurus-Tomahawk rockets were flown in experiments on the auroral acceleration process in discrete auroras. In addition, a radial shaped charge was designed for plasma perturbation experiments.

Viking and Mars Rover exobiology

NASA Technical Reports Server (NTRS)

Schwartz, D. E.; Mancinelli, Rocco L.; Ohara, B. J.

1989-01-01

Other than Earth, Mars is the planet generating the greatest interest among those researching and contemplating the origin and distribution of life throughout the universe. The similarity of the early environments of Earth and Mars, and the biological evolution on early Earth provides the motivation to seriously consider the possibility of a primordial Martian biosphere. In 1975 the Viking project launched two unmanned spacecraft to Mars with the intent of finding evidence of the existence of present or past life on this planet. Three Viking Biology experiments were employed: the Labeled Release experiment, the Gas Exchange Experiment, and the Pyrolytic Release experiment. Each of these three experiments tested for microbial existence and utilization of a substrate by examining the gases evolved from specific chemical reactions. Although the results of these experiments were inconclusive, they inferred that there are no traces of extant life on Mars. However, the experiments did not specifically look for indication of extinct life. Therefore, most of the exobiologic strategies and experiments suggested for the Mars Rover Sample Return Mission involve searching for signature of extinct life. The most significant biological signatures and chemical traces to detect include: isotopic and chemical signatures of metabolic activity, anomalous concentrations of certain metals, trace and microfossils, organically preserved materials, carbonates, nitrates, and evaporites.

Impact of Elevated CO2 on Trace Element Release from Aquifer Sediments of the San Joaquin Valley, CA

NASA Astrophysics Data System (ADS)

Fox, P. M.; Nico, P. S.; Davis, J. A.; Spycher, N.

2014-12-01

Carbon capture and storage (CCS) is a promising technique for mitigating climate change by storing large volumes of carbon dioxide in deep saline aquifers. In California, the thick marine sediments of the Central and Salinas Valleys have been identified as prime targets for future CO2 storage. However, the potential impacts on water quality of overlying drinking-water aquifers must be studied before CCS can be implemented. In this study, we compare trace element release from San Joaquin Valley aquifer sediments with a wide range of textural and redox properties. Kinetic batch experiments were performed with artificial groundwater continuously equilibrated under CO2-saturated (at 1 atm) and background CO2 (0.002-0.006 atm) conditions, resulting in a shift of nearly 3 pH units. In addition, the reversibility of trace element release was studied by sequentially lowering the CO2 from 1.0 atm to 0.5 atm to background concentrations (0.002-0.006 atm) for CO2-saturated systems in order to mimic the dissipation of a CO2 plume in the aquifer. During exposure to high CO2, a number of elements displayed enhanced release compared to background CO2 experiments (Ca, Mg, Li, Si, B, As, Sr, Ni, Fe, Mn, V, Ti, and Co) with concentrations of As, Fe, and Mn exceeding EPA maximum contaminant levels in some cases. On the other hand, Mo and U showed suppressed release. Most intriguing, many of the elements showing enhanced release displayed at least some degree of irreversibility when CO2 concentrations were decreased to background levels. In fact, in some cases (i.e., for V), an element showed further release when CO2 concentrations were decreased. These results suggest that there may be longer-term effects on groundwater quality that persist even after the CO2 plume has dissipated. Several different mechanisms of trace element release including ion exchange, desorption, and carbonate mineral dissolution are explored. Preliminary modeling results suggest that carbonate mineral dissolution can play a key role in driving trace element release even in sediments where carbonates are in low abundance.

Characterization of elemental release during microbe basalt interactions at T = 28 °C

NASA Astrophysics Data System (ADS)

Wu, Lingling; Jacobson, Andrew D.; Chen, Hsin-Chieh; Hausner, Martina

2007-05-01

This study used batch reactors to characterize the rates and mechanisms of elemental release during the interaction of a single bacterial species ( Burkholderia fungorum) with Columbia River Flood Basalt at T = 28 °C for 36 days. We primarily examined the release of Ca, Mg, P, Si, and Sr under a variety of biotic and abiotic conditions with the aim of evaluating how actively metabolizing bacteria might influence basalt weathering on the continents. Four days after inoculating P-limited reactors (those lacking P in the growth medium), the concentration of viable planktonic cells increased from ˜10 4 to 10 8 CFU (Colony Forming Units)/mL, pH decreased from ˜7 to 4, and glucose decreased from ˜1200 to 0 μmol/L. Mass-balance and acid-base equilibria calculations suggest that the lowered pH resulted from either respired CO 2, organic acids released during biomass synthesis, or H + extrusion during NH4+ uptake. Between days 4 and 36, cell numbers remained constant at ˜10 8 CFU/mL and pH increased to ˜5. Purely abiotic control reactors as well as control reactors containing inert cells (˜10 8 CFU/mL) showed constant glucose concentrations, thus confirming the absence of biological activity in these experiments. The pH of all control reactors remained near-neutral, except for one experiment where the pH was initially adjusted to 4 but rapidly rose to 7 within 2 days. Over the entire 36 day period, P-limited reactors containing viable bacteria yielded the highest Ca, Mg, Si, and Sr release rates. Release rates inversely correlate with pH, indicating that proton-promoted dissolution was the dominant reaction mechanism. Both biotic and abiotic P-limited reactors displayed low P concentrations. Chemical analyses of bacteria collected at the end of the experiments, combined with mass-balances between the biological and fluid phases, demonstrate that the absence of dissolved P in the biotic reactors resulted from microbial P uptake. The only P source in the basalt is a small amount of apatite (˜1.2%), which occurs as needles within feldspar grains and glass. We therefore conclude that B. fungorum utilized apatite as a P source for biomass synthesis, which stimulated elemental release from coexisting mineral phases via pH lowering. The results of this study suggest that actively metabolizing bacteria have the potential to influence elemental release from basalt in continental settings.

Episodic Social Stress-Escalated Cocaine Self-Administration: Role of Phasic and Tonic Corticotropin Releasing Factor in the Anterior and Posterior Ventral Tegmental Area.

PubMed

Holly, Elizabeth N; Boyson, Christopher O; Montagud-Romero, Sandra; Stein, Dirson J; Gobrogge, Kyle L; DeBold, Joseph F; Miczek, Klaus A

2016-04-06

Intermittent social defeat stress escalates later cocaine self-administration. Reward and stress both activate ventral tegmental area (VTA) dopamine neurons, increasing downstream extracellular dopamine concentration in the medial prefrontal cortex and nucleus accumbens. The stress neuropeptide corticotropin releasing factor (CRF) and its receptors (CRF-R1, CRF-R2) are located in the VTA and influence dopaminergic activity. These experiments explore how CRF release and the activation of its receptors within the VTA both during and after stress influence later cocaine self-administration in rats.In vivo microdialysis of CRF in the VTA demonstrated that CRF is phasically released in the posterior VTA (pVTA) during acute defeat, but, with repeated defeat, CRF is recruited into the anterior VTA (aVTA) and CRF tone is increased in both subregions. Intra-VTA antagonism of CRF-R1 in the pVTA and CRF-R2 in the aVTA during each social defeat prevented escalated cocaine self-administration in a 24 h "binge." VTA CRF continues to influence cocaine seeking in stressed animals long after social defeat exposure. Unlike nonstressed controls, previously stressed rats show significant cocaine seeking after 15 d of forced abstinence. Previously stressed rats continue to express elevated CRF tone within the VTA and antagonism of pVTA CRF-R1 or aVTA CRF-R2 reverses cocaine seeking. In conclusion, these experiments demonstrate neuroadaptive changes in tonic and phasic CRF with repeated stress, that CRF release during stress may contribute to later escalated cocaine taking, and that persistently elevated CRF tone in the VTA may drive later cocaine seeking through increased activation of pVTA CRF-R1 and aVTA CRF-R2. Corticotropin releasing factor (CRF) within the ventral tegmental area (VTA) has emerged as a likely candidate molecule underlying the fundamental link between stress history and escalated drug self-administration. However, the nature of CRF release in the VTA during acute and repeated stress, as well as its role in enduring neuroadaptations driving later drug taking and seeking, are poorly understood. These experiments explore how CRF is released and interacts with its receptors in specific regions of the VTA both during and after stress to fuel later escalated cocaine taking and seeking behavior. Understanding these acute and persistent changes to the VTA CRF system may lead to better therapeutic interventions for addiction. Copyright © 2016 the authors 0270-6474/16/364094-13$15.00/0.

Episodic Social Stress-Escalated Cocaine Self-Administration: Role of Phasic and Tonic Corticotropin Releasing Factor in the Anterior and Posterior Ventral Tegmental Area

PubMed Central

Boyson, Christopher O.; Montagud-Romero, Sandra; Stein, Dirson J.; Gobrogge, Kyle L.; DeBold, Joseph F.; Miczek, Klaus A.

2016-01-01

Intermittent social defeat stress escalates later cocaine self-administration. Reward and stress both activate ventral tegmental area (VTA) dopamine neurons, increasing downstream extracellular dopamine concentration in the medial prefrontal cortex and nucleus accumbens. The stress neuropeptide corticotropin releasing factor (CRF) and its receptors (CRF-R1, CRF-R2) are located in the VTA and influence dopaminergic activity. These experiments explore how CRF release and the activation of its receptors within the VTA both during and after stress influence later cocaine self-administration in rats. In vivo microdialysis of CRF in the VTA demonstrated that CRF is phasically released in the posterior VTA (pVTA) during acute defeat, but, with repeated defeat, CRF is recruited into the anterior VTA (aVTA) and CRF tone is increased in both subregions. Intra-VTA antagonism of CRF-R1 in the pVTA and CRF-R2 in the aVTA during each social defeat prevented escalated cocaine self-administration in a 24 h “binge.” VTA CRF continues to influence cocaine seeking in stressed animals long after social defeat exposure. Unlike nonstressed controls, previously stressed rats show significant cocaine seeking after 15 d of forced abstinence. Previously stressed rats continue to express elevated CRF tone within the VTA and antagonism of pVTA CRF-R1 or aVTA CRF-R2 reverses cocaine seeking. In conclusion, these experiments demonstrate neuroadaptive changes in tonic and phasic CRF with repeated stress, that CRF release during stress may contribute to later escalated cocaine taking, and that persistently elevated CRF tone in the VTA may drive later cocaine seeking through increased activation of pVTA CRF-R1 and aVTA CRF-R2. SIGNIFICANCE STATEMENT Corticotropin releasing factor (CRF) within the ventral tegmental area (VTA) has emerged as a likely candidate molecule underlying the fundamental link between stress history and escalated drug self-administration. However, the nature of CRF release in the VTA during acute and repeated stress, as well as its role in enduring neuroadaptations driving later drug taking and seeking, are poorly understood. These experiments explore how CRF is released and interacts with its receptors in specific regions of the VTA both during and after stress to fuel later escalated cocaine taking and seeking behavior. Understanding these acute and persistent changes to the VTA CRF system may lead to better therapeutic interventions for addiction. PMID:27053215

Reactive Transport of Marcellus Shale Waters in Natural Aquifers: the Role of Mineralogical Compositions and Spatial Distribution Patterns

NASA Astrophysics Data System (ADS)

Cai, Z.; Wen, H.; Li, L.

2017-12-01

Accidental release of Marcellus Shale waters (MSW) can release high concentrations of chemicals that can deteriorate groundwater quality. It is important to understand the reactive transport and fate of chemicals from MSW. Natural aquifers typically have complex mineralogical compositions and are heterogeneous with large spatial variation in terms of physical and geochemical properties. To investigate the effects of mineralogical compositions, flow-through experiments and reactive transport modeling were carried out using 3 large columns (5 cm×50 cm, Quartz, Calcite, and Vermiculite). Results indicate calcite immobilizes heavy metals by precipitation and solid solution partitioning (coprecipitation). Vermiculite retards heavy metals through ion exchange. The sorbed chemicals however slowly release back to the groundwater. Na and Ca transport similarly to Br in Qtz and Cal columns however become sorbed in Vrm column during release through ion exchange by 27.8% and 46.5%, respectively and later slowly release back to aqueous phase. To understand the role of mineral spatial patterns, three 2D flow-cell (40 cm×12 cm×1 cm) experiments were carried out. All flow cells have the same clay mass within quartz matrix but different spatial patterns characterized by the relative length of the clay zone ( 0, ¼, ½) of the domain length (L). Results show that in the uniform column, ion exchange dominates and most Ba sorbs to the solid phase, to an extent Ba cannot precipitate out with SO4 as barite. In 1/2-Zone, however, most Ba precipitates as barite. In 1/4-Zone, both ion exchange and mineral precipitation occur. In general, the 1/2-Zone has the smallest ion exchange capacity for other species including Na, Ca, Mg, K and heavy metals (Mn, Cu, Zn, Cd and Pb) as well. Our flow cell experiment emphasizes the importance of mineral spatial patterns in regulating not only reaction rates but also the type of reactions in controlling the reactive transport of MSW chemicals. The column study suggests in carbonate rich aquifers, carbonate facilitate natural attenuation. In clay-rich aquifers, such as sandstone aquifers, clay helps alleviate the cation during MSW release however these sorbed cations will ultimately release back to the aqueous phase. In sand and gravel aquifers, mixing process primarily controls the concentration level.

FLORIDA TOWER FOOTPRINT EXPERIMENTS

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

WATSON,T.B.; DIETZ, R.N.; WILKE, R.

2007-01-01

The Florida Footprint experiments were a series of field programs in which perfluorocarbon tracers were released in different configurations centered on a flux tower to generate a data set that can be used to test transport and dispersion models. These models are used to determine the sources of the CO{sub 2} that cause the fluxes measured at eddy covariance towers. Experiments were conducted in a managed slash pine forest, 10 km northeast of Gainesville, Florida, in 2002, 2004, and 2006 and in atmospheric conditions that ranged from well mixed, to very stable, including the transition period between convective conditions atmore » midday to stable conditions after sun set. There were a total of 15 experiments. The characteristics of the PFTs, details of sampling and analysis methods, quality control measures, and analytical statistics including confidence limits are presented. Details of the field programs including tracer release rates, tracer source configurations, and configuration of the samplers are discussed. The result of this experiment is a high quality, well documented tracer and meteorological data set that can be used to improve and validate canopy dispersion models.« less

Wakata in the JPM

NASA Image and Video Library

2013-11-15

View of Koichi Wakata,Expedition 38 Flight Engineer (FE),in the Japanese Experiment Module (JEM) Pressurized Module (JPM). JEM Small Satellite Orbital Deployer (J-SSOD) installed on the Multi-Purpose Experiment Platform (MPEP),is visible. Photo was taken during Expedition 38. Image was released by astronaut on Twitter.

Effect of Disinfectant Exposure on Legionella pneumophila Associated with Simulated Drinking Water Biofilms: Release, Inactivation, and Infectivity.

PubMed

Shen, Yun; Huang, Conghui; Lin, Jie; Wu, Wenjing; Ashbolt, Nicholas J; Liu, Wen-Tso; Nguyen, Thanh H

2017-02-21

Legionella pneumophila, the most commonly identified causative agent in drinking water associated with disease outbreaks, can be harbored by and released from drinking water biofilms. In this study, the release of biofilm-associated L. pneumophila under simulated drinking water flow containing a disinfectant residual was examined. Meanwhile, the inactivation and infectivity (to amoebae) of the released L. pneumophila were studied. To simulate drinking water system conditions, biofilms were prepared under either disinfectant exposure (predisinfected biofilms) or disinfectant-free (untreated biofilms) conditions, respectively. For experiments with water flow containing a disinfectant to release the biofilm-associated L. pneumophila from these two types of biofilms, the L. pneumophila release kinetics values from predisinfected and untreated biofilms under flow condition were not statistically different (one-way ANOVA, p > 0.05). However, inactivation of the L. pneumophila released from predisinfected biofilms was 1-2 times higher and amoeba infectivity was 2-29 times lower than that from untreated biofilms. The higher disinfectant resistance of L. pneumophila released from untreated biofilms was presumably influenced by the detachment of a larger amount of biofilm material (determined by 16S rRNA qPCR) surrounding the released L. pneumophila. This study highlights the interaction among disinfectant residual, biofilms, and L. pneumophila, which provides guidelines to assess and control pathogen risk.

Floating tablets for controlled release of ofloxacin via compression coating of hydroxypropyl cellulose combined with effervescent agent.

PubMed

Qi, Xiaole; Chen, Haiyan; Rui, Yao; Yang, Fengjiao; Ma, Ning; Wu, Zhenghong

2015-07-15

To prolong the residence time of dosage forms within gastrointestinal trace until all drug released at desired rate was one of the real challenges for oral controlled-release drug delivery system. Herein, we developed a fine floating tablet via compression coating of hydrophilic polymer (hydroxypropyl cellulose) combined with effervescent agent (sodium bicarbonate) to achieve simultaneous control of release rate and location of ofloxacin. Sodium alginate was also added in the coating layer to regulate the drug release rate. The effects of the weight ratio of drug and the viscosity of HPC on the release profile were investigated. The optimized formulations were found to immediately float within 30s and remain lastingly buoyant over a period of 12 h in simulated gastric fluid (SGF, pH 1.2) without pepsin, indicating a satisfactory floating and zero-order drug release profile. In addition, the oral bioavailability experiment in New Zealand rabbits showed that, the relative bioavailability of the ofloxacin after administrated of floating tablets was 172.19%, compared to marketed common release tablets TaiLiBiTuo(®). These results demonstrated that those controlled-released floating tables would be a promising gastro-retentive delivery system for drugs acting in stomach. Copyright © 2015 Elsevier B.V. All rights reserved.

In-pile test of Li 2TiO 3 pebble bed with neutron pulse operation

NASA Astrophysics Data System (ADS)

Tsuchiya, K.; Nakamichi, M.; Kikukawa, A.; Nagao, Y.; Enoeda, M.; Osaki, T.; Ioki, K.; Kawamura, H.

2002-12-01

Lithium titanate (Li 2TiO 3) is one of the candidate materials as tritium breeder in the breeding blanket of fusion reactors, and it is necessary to show the tritium release behavior of Li 2TiO 3 pebble beds. Therefore, a blanket in-pile mockup was developed and in situ tritium release experiments with the Li 2TiO 3 pebble bed were carried out in the Japan Materials Testing Reactor. In this study, the relationship between tritium release behavior from Li 2TiO 3 pebble beds and effects of various parameters were evaluated. The ( R/ G) ratio of tritium release ( R) and tritium generation ( G) was saturated when the temperature at the outside edge of the Li 2TiO 3 pebble bed became 300 °C. The tritium release amount increased cycle by cycle and saturated after about 20 pulse operations.

Composite chitosan hydrogels for extended release of hydrophobic drugs.

PubMed

Delmar, Keren; Bianco-Peled, Havazelet

2016-01-20

A composite chitosan hydrogel durable in physiological conditions intended for sustained release of hydrophobic drugs was investigated. The design is based on chitosan crosslinked with genipin with embedded biocompatible non-ionic microemulsion (ME). A prolonged release period of 48 h in water, and of 24h in phosphate buffer saline (PBS) of pH 7.4 was demonstrated for Nile red and curcumin. The differences in release patterns in water and PBS were attributed to distinct dissimilarities in the swelling behaviors; in water, the hydrogels swell enormously, while in PBS they expel water and shrink. The release mechanism dominating this system is complex due to intermolecular bonding between the oil droplets and the polymeric network, as confirmed by Fourier transform infrared spectroscopy (FTIR) experiments. This is the first time that oil in water microemulsions were introduced into a chitosan hydrogels for the creation of a hydrophobic drug delivery system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Extension of the Hugoniot and analytical release model of α-quartz to 0.2–3 TPa

DOE PAGES

Desjarlais, M. P.; Knudson, M. D.; Cochrane, K. R.

2017-07-21

In recent years, α-quartz has been used prolifically as an impedance matching standard in shock wave experiments in the multi-Mbar regime (1 Mbar = 100 GPa = 0.1 TPa). This is due to the fact that above ~90–100 GPa along the principal Hugoniot α-quartz becomes reflective, and thus, shock velocities can be measured to high precision using velocity interferometry. The Hugoniot and release of α-quartz have been studied extensively, enabling the development of an analytical release model for use in impedance matching. However, this analytical release model has only been validated over a range of 300–1200 GPa (0.3–1.2 TPa). Furthermore,more » we extend this analytical model to 200–3000 GPa (0.2–3 TPa) through additional α-quartz Hugoniot and release measurements, as well as first-principles molecular dynamics calculations.« less

Pinosylvin-Based Polymers: Biodegradable Poly(Anhydride-Esters) for Extended Release of Antibacterial Pinosylvin.

PubMed

Bien-Aime, Stephan; Yu, Weiling; Uhrich, Kathryn E

2016-07-01

Pinosylvin is a natural stilbenoid known to exhibit antibacterial bioactivity against foodborne bacteria. In this work, pinosylvin is chemically incorporated into a poly(anhydride-ester) (PAE) backbone via melt-condensation polymerization, and characterized with respect to its physicochemical and thermal properties. In vitro release studies demonstrate that pinosylvin-based PAEs hydrolytically degrade over 40 d to release pinosylvin. Pseudo-first order kinetic experiments on model compounds, butyric anhydride and 3-butylstilbene ester, indicate that the anhydride linkages hydrolyze first, followed by the ester bonds to ultimately release pinosylvin. An antibacterial assay shows that the released pinosylvin exhibit bioactivity, while in vitro cytocompatibility studies demonstrate that the polymer is noncytotoxic toward fibroblasts. These preliminary findings suggest that the pinosylvin-based PAEs can serve as food preservatives in food packaging materials by safely providing antibacterial bioactivity over extended time periods. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation and Characterization of Azadirachtin Alginate-Biosorbent Based Formulations: Water Release Kinetics and Photodegradation Study.

PubMed

Flores-Céspedes, Francisco; Martínez-Domínguez, Gerardo P; Villafranca-Sánchez, Matilde; Fernández-Pérez, Manuel

2015-09-30

The botanical insecticide azadirachtin was incorporated in alginate-based granules to obtain controlled release formulations (CRFs). The basic formulation [sodium alginate (1.47%) - azadirachtin (0.28%) - water] was modified by the addition of biosorbents, obtaining homogeneous hybrid hydrogels with high azadirachtin entrapment efficiency. The effect on azadirachtin release rate caused by the incorporation of biosorbents such as lignin, humic acid, and olive pomace in alginate formulation was studied by immersion of the granules in water under static conditions. The addition of the biosorbents to the basic alginate formulation reduces the rate of release because the lignin-based formulation produces a slower release. Photodegradation experiments showed the potential of the prepared formulations in protecting azadirachtin against simulated sunlight, thus improving its stability. The results showed that formulation prepared with lignin provided extended protection. Therefore, this study provides a new procedure to encapsulate the botanical insecticide azadirachtin, improving its delivery and photostability.

Artificial neural networks in evaluation and optimization of modified release solid dosage forms.

PubMed

Ibrić, Svetlana; Djuriš, Jelena; Parojčić, Jelena; Djurić, Zorica

2012-10-18

Implementation of the Quality by Design (QbD) approach in pharmaceutical development has compelled researchers in the pharmaceutical industry to employ Design of Experiments (DoE) as a statistical tool, in product development. Among all DoE techniques, response surface methodology (RSM) is the one most frequently used. Progress of computer science has had an impact on pharmaceutical development as well. Simultaneous with the implementation of statistical methods, machine learning tools took an important place in drug formulation. Twenty years ago, the first papers describing application of artificial neural networks in optimization of modified release products appeared. Since then, a lot of work has been done towards implementation of new techniques, especially Artificial Neural Networks (ANN) in modeling of production, drug release and drug stability of modified release solid dosage forms. The aim of this paper is to review artificial neural networks in evaluation and optimization of modified release solid dosage forms.

Artificial Neural Networks in Evaluation and Optimization of Modified Release Solid Dosage Forms

PubMed Central

Ibrić, Svetlana; Djuriš, Jelena; Parojčić, Jelena; Djurić, Zorica

2012-01-01

Implementation of the Quality by Design (QbD) approach in pharmaceutical development has compelled researchers in the pharmaceutical industry to employ Design of Experiments (DoE) as a statistical tool, in product development. Among all DoE techniques, response surface methodology (RSM) is the one most frequently used. Progress of computer science has had an impact on pharmaceutical development as well. Simultaneous with the implementation of statistical methods, machine learning tools took an important place in drug formulation. Twenty years ago, the first papers describing application of artificial neural networks in optimization of modified release products appeared. Since then, a lot of work has been done towards implementation of new techniques, especially Artificial Neural Networks (ANN) in modeling of production, drug release and drug stability of modified release solid dosage forms. The aim of this paper is to review artificial neural networks in evaluation and optimization of modified release solid dosage forms. PMID:24300369

Plasma peptide YY (PYY) in dumping syndrome.

PubMed

Adrian, T E; Long, R G; Fuessl, H S; Bloom, S R

1985-12-01

The newly isolated hormonal peptide PYY is mainly localized to endocrine cells of the lower intestinal mucosa. The release of PYY by oral glucose was studied in six patients with the dumping syndrome to ascertain the effect of this condition on PYY release. Plasma PYY concentrations were greatly increased following oral glucose in patients with the dumping syndrome compared with healthy controls. In a separate series of experiments, the effect of somatostatin infusion on the PYY release by glucose in these patients was investigated. The release of PYY was completely blocked by infusion of somatostatin, and its release from the bowel in normal subjects may therefore be modulated by local somatostatin in the gut. PYY has been shown to inhibit gastric acid secretion and emptying, at plasma concentrations similar to those seen after glucose, in patients with the dumping syndrome. PYY may therefore be a factor involved in the pathophysiological changes associated with this condition.

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

McKenzie-Carter, M.A.; Lyon, R.E.; Rope, S.K.

This report contains information to support the Environmental Assessment for the Burning Plasma Experiment (BPX) Project proposed for the Princeton Plasma Physics Laboratory (PPPL). The assumptions and methodology used to assess the impact to members of the public from operational and accidental releases of radioactive material from the proposed BPX during the operational period of the project are described. A description of the tracer release tests conducted at PPPL by NOAA is included; dispersion values from these tests are used in the dose calculations. Radiological releases, doses, and resulting health risks are calculated and summarized. The computer code AIRDOS- EPA,more » which is part of the computer code system CAP-88, is used to calculate the individual and population doses for routine releases; FUSCRAC3 is used to calculate doses resulting from off-normal releases where direct application of the NOAA tracer test data is not practical. Where applicable, doses are compared to regulatory limits and guideline values. 48 refs., 16 tabs.« less

Three-Dimensional Electromagnetic Monte Carlo Particle-in-Cell Simulations of Critical Ionization Velocity Experiments in Space

NASA Technical Reports Server (NTRS)

Wang, J.; Biasca, R.; Liewer, P. C.

1996-01-01

Although the existence of the critical ionization velocity (CIV) is known from laboratory experiments, no agreement has been reached as to whether CIV exists in the natural space environment. In this paper we move towards more realistic models of CIV and present the first fully three-dimensional, electromagnetic particle-in-cell Monte-Carlo collision (PIC-MCC) simulations of typical space-based CIV experiments. In our model, the released neutral gas is taken to be a spherical cloud traveling across a magnetized ambient plasma. Simulations are performed for neutral clouds with various sizes and densities. The effects of the cloud parameters on ionization yield, wave energy growth, electron heating, momentum coupling, and the three-dimensional structure of the newly ionized plasma are discussed. The simulations suggest that the quantitative characteristics of momentum transfers among the ion beam, neutral cloud, and plasma waves is the key indicator of whether CIV can occur in space. The missing factors in space-based CIV experiments may be the conditions necessary for a continuous enhancement of the beam ion momentum. For a typical shaped charge release experiment, favorable CIV conditions may exist only in a very narrow, intermediate spatial region some distance from the release point due to the effects of the cloud density and size. When CIV does occur, the newly ionized plasma from the cloud forms a very complex structure due to the combined forces from the geomagnetic field, the motion induced emf, and the polarization. Hence the detection of CIV also critically depends on the sensor location.

Release of substance P from the cat spinal cord.

PubMed Central

Go, V L; Yaksh, T L

1987-01-01

1. The present experiments examine the physiology and pharmacology of the release of substance P-like immunoreactivity (SP-l.i.), from the spinal cord in the halothane-anaesthetized, artificially ventilated cat. 2. Resting release of SP-l.i. was 36 +/- 4 fmol/30 min (mean +/- S.E.; n = 106). Bilateral stimulation of the sciatic nerves at intensities which evoked activity in fibres conducting at A beta conduction velocities (greater than 40 m/s), resulted in no change in blood pressure, pupil diameter or release of SP-l.i. Stimulation intensities which activate fibres conducting at velocities less than 2 m/s resulted in increased blood pressure, miosis and elevated release of SP-l.i. (278 +/- 16% of control). 3. The relationship between nerve-stimulation frequency and release was monotonic up to approximately 20 Hz. Higher stimulation frequencies did not increase the amounts of SP-l.i. released. At 200 Hz there was a reduction. 4. Capsaicin (0.1 mM) increased the release of SP-l.i. from the spinal cord and resulted in an acute desensitization to subsequent nerve stimulation. This acute effect was not accompanied by a reduction in spinal levels of SP-l.i. measured 2 h after stimulation. 5. Cold block of the cervical spinal cord resulted in an increase in the amounts of SP-l.i. released by nerve stimulation. 6. Pre-treatment with intrathecal 5,6-dihydroxytryptamine (300 micrograms) 7 days prior to the experiment caused a reduction in the dorsal and ventral horn stores of SP-l.i., but had no effect on the release of SP-l.i. evoked by nerve stimulation. Similar pre-treatment with intrathecal capsaicin (300 micrograms) resulted in depletion of SP-l.i. in the dorsal but not in the ventral horn of the spinal cord and diminished the release of SP-l.i. evoked by nerve stimulation. 7. Intense thermal stimulation of the flank resulted in small (20-35%), but reliable increases in the release of SP-l.i. above control. 8. Putative agonists for the opioid mu-receptor (morphine, 10-100 microM; sufentanil, 1 microM), and for the delta-receptor (D-Ala2-D-Leu5-enkephalin, 1-10 microM; D-Pen2-D-Pen5-enkephalin, 10 microM), but not the kappa-receptor (U50488H, 100-1000 microM), produced a dose-dependent, naloxone-reversible reduction of the evoked, but not of the resting release of SP-l.i. (-)-Naloxone, but not (+)-naloxone, resulted in a significant increase in evoked but not resting SP-l.i. release.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2451003

Delayed Release from Proactive Interference with Meaningful Material: How Much Do We Remember After Reading Brief Prose Passages?

ERIC Educational Resources Information Center

Blumenthal, Gary B.; Robbins, Donald

1977-01-01

Three experiments were conducted, investigating the buildup of and the release from proactive interference, in which the stimulus materials were brief prose passages about specific topics. Each passage was followed by a multiple-choice test, and then a final test on all the passages read was given. Implications of the data for standardized tests…

Vesicle Motion during Sustained Exocytosis in Chromaffin Cells: Numerical Model Based on Amperometric Measurements.

PubMed

Jarukanont, Daungruthai; Bonifas Arredondo, Imelda; Femat, Ricardo; Garcia, Martin E

2015-01-01

Chromaffin cells release catecholamines by exocytosis, a process that includes vesicle docking, priming and fusion. Although all these steps have been intensively studied, some aspects of their mechanisms, particularly those regarding vesicle transport to the active sites situated at the membrane, are still unclear. In this work, we show that it is possible to extract information on vesicle motion in Chromaffin cells from the combination of Langevin simulations and amperometric measurements. We developed a numerical model based on Langevin simulations of vesicle motion towards the cell membrane and on the statistical analysis of vesicle arrival times. We also performed amperometric experiments in bovine-adrenal Chromaffin cells under Ba2+ stimulation to capture neurotransmitter releases during sustained exocytosis. In the sustained phase, each amperometric peak can be related to a single release from a new vesicle arriving at the active site. The amperometric signal can then be mapped into a spike-series of release events. We normalized the spike-series resulting from the current peaks using a time-rescaling transformation, thus making signals coming from different cells comparable. We discuss why the obtained spike-series may contain information about the motion of all vesicles leading to release of catecholamines. We show that the release statistics in our experiments considerably deviate from Poisson processes. Moreover, the interspike-time probability is reasonably well described by two-parameter gamma distributions. In order to interpret this result we computed the vesicles' arrival statistics from our Langevin simulations. As expected, assuming purely diffusive vesicle motion we obtain Poisson statistics. However, if we assume that all vesicles are guided toward the membrane by an attractive harmonic potential, simulations also lead to gamma distributions of the interspike-time probability, in remarkably good agreement with experiment. We also show that including the fusion-time statistics in our model does not produce any significant changes on the results. These findings indicate that the motion of the whole ensemble of vesicles towards the membrane is directed and reflected in the amperometric signals. Our results confirm the conclusions of previous imaging studies performed on single vesicles that vesicles' motion underneath plasma membranes is not purely random, but biased towards the membrane.

Vesicle Motion during Sustained Exocytosis in Chromaffin Cells: Numerical Model Based on Amperometric Measurements

PubMed Central

Jarukanont, Daungruthai; Bonifas Arredondo, Imelda; Femat, Ricardo; Garcia, Martin E.

2015-01-01

Chromaffin cells release catecholamines by exocytosis, a process that includes vesicle docking, priming and fusion. Although all these steps have been intensively studied, some aspects of their mechanisms, particularly those regarding vesicle transport to the active sites situated at the membrane, are still unclear. In this work, we show that it is possible to extract information on vesicle motion in Chromaffin cells from the combination of Langevin simulations and amperometric measurements. We developed a numerical model based on Langevin simulations of vesicle motion towards the cell membrane and on the statistical analysis of vesicle arrival times. We also performed amperometric experiments in bovine-adrenal Chromaffin cells under Ba2+ stimulation to capture neurotransmitter releases during sustained exocytosis. In the sustained phase, each amperometric peak can be related to a single release from a new vesicle arriving at the active site. The amperometric signal can then be mapped into a spike-series of release events. We normalized the spike-series resulting from the current peaks using a time-rescaling transformation, thus making signals coming from different cells comparable. We discuss why the obtained spike-series may contain information about the motion of all vesicles leading to release of catecholamines. We show that the release statistics in our experiments considerably deviate from Poisson processes. Moreover, the interspike-time probability is reasonably well described by two-parameter gamma distributions. In order to interpret this result we computed the vesicles’ arrival statistics from our Langevin simulations. As expected, assuming purely diffusive vesicle motion we obtain Poisson statistics. However, if we assume that all vesicles are guided toward the membrane by an attractive harmonic potential, simulations also lead to gamma distributions of the interspike-time probability, in remarkably good agreement with experiment. We also show that including the fusion-time statistics in our model does not produce any significant changes on the results. These findings indicate that the motion of the whole ensemble of vesicles towards the membrane is directed and reflected in the amperometric signals. Our results confirm the conclusions of previous imaging studies performed on single vesicles that vesicles’ motion underneath plasma membranes is not purely random, but biased towards the membrane. PMID:26675312

Guidance for Evaluating the Safety of Experimental Releases of Mosquitoes, Emphasizing Mark-Release-Recapture Techniques.

PubMed

Benedict, Mark Q; Charlwood, J Derek; Harrington, Laura C; Lounibos, L Philip; Reisen, William K; Tabachnick, Walter J

2018-01-01

Experimental releases of mosquitoes are performed to understand characteristics of populations related to the biology, ability to transmit pathogens, and ultimately their control. In this article, we discuss considerations related to the safety of experimental releases of living mosquitoes, applying principles of good practice in vector biology that protect human health and comfort. We describe specific factors of experimental releases of mosquitoes that we believe are critical to inform institutional biosafety committees and similar review boards to which proposals to conduct mosquito release experiments have been submitted. In this study, "experimental releases" means those that do not significantly increase vector capacity or nuisance biting relative to the unperturbed natural baseline. This document specifically does not address releases of mosquitoes for ongoing control programs or trials of new control methods for which broader assessments of risk are required. It also does not address releases of transgenic or exotic (non-native) mosquito species, both of which require particular regulatory approval. Experimental releases may include females and males and evaluation must consider their effects based on the number released, their genotype and phenotype, the environment into which they are released, and postrelease collection activities. We consider whether increases of disease transmission and nuisance biting might result from proposed experimental releases against the backdrop of natural population size variation. We recommend that experimental releases be conducted in a manner that can be reasonably argued to have insignificant negative effects. Reviewers of proposals for experimental releases should expect applicants to provide such an argument based on evidence from similar studies and their planned activities. This document provides guidance for creating and evaluating such proposals.

Macroscopic and microscopic observations of particle-facilitated mercury transport from New Idria and Sulphur Bank mercury mine tailings

USGS Publications Warehouse

Lowry, G.V.; Shaw, S.; Kim, C.S.; Rytuba, J.J.; Brown, Gordon E.

2004-01-01

Mercury (Hg) release from inoperative Hg mines in the California Coast Range has been documented, but little is known about the release and transport mechanisms. In this study, tailings from Hg mines located in different geologic settings-New Idria (NI), a Si-carbonate Hg deposit, and Sulphur Bank (SB), a hot-spring Hg deposit-were characterized, and particle release from these wastes was studied in column experiments to (1) investigate the mechanisms of Hg release from NI and SB mine wastes, (2) determine the speciation of particle-bound Hg released from the mine wastes, and (3) determine the effect of calcinations on Hg release processes. The physical and chemical properties of tailings and the colloids released from them were determined using chemical analyses, selective chemical extractions, XRD, SEM, TEM, and X-ray absorption spectroscopy techniques. The total Hg concentration in tailings increased with decreasing particle size in NI and SB calcines (roasted ore), but reached a maximum at an intermediate particle size in the SB waste rock (unroasted ore). Hg in the tailings exists predominantly as low-solubility HgS (cinnabar and metacinnabar), with NI calcines having >50% HgS, SB calcines having >89% HgS, and SB waste rock having ???100% HgS. Leaching experiments with a high-ionic-strength solution (0.1 M NaCl) resulted in a rapid but brief release of soluble and particulate Hg. Lowering the ionic strength of the leach solution (0.005 M NaCl) resulted in the release of colloidal Hg from two of the three mine wastes studied (NI calcines and SB waste rock). Colloid-associated Hg accounts for as much as 95% of the Hg released during episodic particle release. Colloids generated from the NI calcines are produced by a breakup and release mechanism and consist of hematite, jarosite/alunite, and Al-Si gel with particle sizes of 10-200 nm. ATEM and XAFS analyses indicate that the majority (???78%) of the mercury is present in the form of HgS. SB calcines also produced HgS colloids. The colloids generated from the SB waste rock were heterogeneous and varied in composition according to the column influent composition. ATEM and XAFS results indicate that Hg is entirely in the HgS form. Data from this study identify colloidal HgS as the dominant transported form of Hg from these mine waste materials.

Plasma effects of active ion beam injections in the ionosphere at rocket altitudes

NASA Technical Reports Server (NTRS)

Arnoldy, R. L.; Cahill, L. J., Jr.; Kintner, P. M.; Moore, T. E.; Pollock, C. J.

1992-01-01

Data from ARCS rocket ion beam injection experiments are primarily discussed. There are three results from this series of active experiments that are of particular interest in space plasma physics. These are the transverse acceleration of ambient ions in the large beam volume, the scattering of beam ions near the release payload, and the possible acceleration of electrons very close to the plasma generator which produce intense high frequency waves. The ability of 100 ma ion beam injections into the upper E and F regions of the ionosphere to produce these phenomena appear to be related solely to the process by which the plasma release payload and the ion beam are neutralized. Since the electrons in the plasma release do not convect with the plasma ions, the neutralization of both the payload and beam must be accomplished by large field-aligned currents (milliamperes/square meter) which are very unstable to wave growth of various modes.

Dispersal of Male Aedes aegypti in a Coastal Village in Southern Mexico

PubMed Central

Valerio, Laura; Facchinelli, Luca; Ramsey, Janine M.; Scott, Thomas W.

2012-01-01

Most Aedes aegypti dispersal studies have focused on females because of their central role in dengue virus transmission. Only a few mark-release-recapture (MRR) studies provided insights into male Ae. aegypti dispersal. To fill this knowledge gap, we conducted five male Ae. aegypti MRR experiments in a coastal village in southern Mexico. Small and large male cohorts were marked with fluorescent dusts, released outside buildings, and recaptures were carried out by using backpack aspirators. Recapture rates ranged between 0.35% and 6.55% and median distance traveled was 12–166 meters. A statistically significant difference in median distance traveled with large males dispersing farther than small ones was detected only in one experiment (MRR5: U = 3.5, P < 0.01). Male dispersal data will be useful for constructing and estimating parameter values and validating models that will be used to plan the most effective release strategies for genetically modified male Ae. aegypti. PMID:22492152

Interspecific competition between Snellenius manilae and Meteorus pulchricornis, larval parasitoids of Spodoptera litura.

PubMed

Chen, W-T; Hwang, S-Y

2015-10-01

Snellenius manilae (Ashmead) and Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae) are larval endoparasitoids of Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). Both species preferentially parasitize early-instar S. litura and occupy similar ecological niches. Therefore, competition between the two species may occur. In this study, intrinsic competition and cage experiments were conducted to discuss the interactions between S. manilae and M. pulchricornis. The results indicated that in intrinsic competition, M. pulchricornis was always the dominant species. In cage experiments, when the total number of parasitoids was four, the parasitism rates following the release of one species were significantly higher than the release of two species simultaneously. In addition, parasitism rate of eight M. pulchricornis was also significantly higher than the parasitism rate of the treatment released four S. manilae and four M. pulchricornis simultaneously. Therefore, competition occurs between S. manilae and M. pulchricornis, and M. pulchricornis is typically the superior of the two species. The use of M. pulchricornis as a biological agent for S. litura should be considered.

Competitive interactions and controlled release of a natural antioxidant from halloysite nanotubes.

PubMed

Hári, József; Gyürki, Ádám; Sárközi, Márk; Földes, Enikő; Pukánszky, Béla

2016-01-15

Halloysite nanotubes used as potential carrier material for a controlled release stabilizer in polyethylene were thoroughly characterized with several techniques including the measurement of specific surface area, pore volume and surface energy. The high surface energy of the halloysite results in the strong bonding of the additive to the surface. Dissolution experiments carried out with eight different solvents for the determination of the effect of solvent characteristics on the amount of irreversibly bonded quercetin proved that adsorption and dissolution depend on competitive interactions prevailing in the system. Solvents with low polarity dissolve only surplus quercetin adsorbed in multilayers. Polyethylene is a very apolar polymer forming weak interactions with every substance; quercetin dissolves into it from the halloysite surface only above a critical surface coverage. Stabilization experiments confirmed that strong adhesion prevents dissolution and results in limited stabilization efficiency. At larger adsorbed amounts better stability and extended effect were measured indicating dissolution and controlled release. Copyright © 2015 Elsevier Inc. All rights reserved.

Canada Basin Acoustic Propagation Experiment (CANAPE)

DTIC Science & Technology

2015-09-30

1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Canada Basin Acoustic Propagation Experiment (CANAPE...ocean structure. Changes in sea ice and the water column affect both acoustic propagation and ambient noise. This implies that what was learned...about Arctic acoustics during the Cold War is now obsolete. The goal of the Canada Basin Acoustic Propagation Experiment (CANAPE) is to determine the

The Viking biology results

NASA Technical Reports Server (NTRS)

Klein, Harold P.

1989-01-01

A brief review of the purposes and the results from the Viking Biology experiments is presented, in the expectation that the lessons learned from this mission will be useful in planning future approaches to the biological exploration of Mars. Since so little was then known about potential micro-environments on Mars, three different experiments were included in the Viking mission, each one based on different assumptions about what Martian organisms might be like. In addition to the Viking Biology Instrument (VBI), important corollary information was obtained from the Viking lander imaging system and from the molecular analysis experiments that were conducted using the gas chromatograph-mass spectrometer (GCMS) instrument. No biological objects were noted by the lander imaging instrument. The GCMS did not detect any organic compounds. A description of the tests conducted by the Gas Exchange Experiment, the Labeled Release experiment, and the Pyrolytic Release experiment is given. Results are discussed. Taken as a whole, the Viking data yielded no unequivocal evidence for a Martian biota at either landing site. The results also revealed the presence of one or more reactive oxidants in the surface material and these need to be further characterized, as does the range of micro-environments, before embarking upon future searches for extant life on Mars.

Using task dynamics to quantify the affordances of throwing for long distance and accuracy.

PubMed

Wilson, Andrew D; Weightman, Andrew; Bingham, Geoffrey P; Zhu, Qin

2016-07-01

In 2 experiments, the current study explored how affordances structure throwing for long distance and accuracy. In Experiment 1, 10 expert throwers (from baseball, softball, and cricket) threw regulation tennis balls to hit a vertically oriented 4 ft × 4 ft target placed at each of 9 locations (3 distances × 3 heights). We measured their release parameters (angle, speed, and height) and showed that they scaled their throws in response to changes in the target's location. We then simulated the projectile motion of the ball and identified a continuous subspace of release parameters that produce hits to each target location. Each subspace describes the affordance of our target to be hit by a tennis ball moving in a projectile motion to the relevant location. The simulated affordance spaces showed how the release parameter combinations required for hits changed with changes in the target location. The experts tracked these changes in their performance and were successful in hitting the targets. We next tested unusual (horizontal) targets that generated correspondingly different affordance subspaces to determine whether the experts would track the affordance to generate successful hits. Do the experts perceive the affordance? They do. In Experiment 2, 5 cricketers threw to hit either vertically or horizontally oriented targets and successfully hit both, exhibiting release parameters located within the requisite affordance subspaces. We advocate a task dynamical approach to the study of affordances as properties of objects and events in the context of tasks as the future of research in this area. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Osteoinductive effect of bone bank allografts on human osteoblasts in culture.

PubMed

de la Piedra, Concepción; Vicario, Carlos; de Acuña, Lucrecia Rodríguez; García-Moreno, Carmen; Traba, Maria Luisa; Arlandis, Santiago; Marco, Fernando; López-Durán, Luis

2008-02-01

Incorporation of a human bone allograft requires osteoclast activity and growth of recipient osteoblasts. The aim of this work was to study the effects produced by autoclavated and -80 degrees C frozen bone allografts on osteoblast proliferation and synthesis of interleukin 6 (IL6), activator of bone resorption, aminoterminal propeptide of procollagen I (PINP), marker of bone matrix formation, and osteoprotegerin (OPG), inhibitor of osteoclast activity and differentiation. Allografts were obtained from human femoral heads. Human osteoblasts were cultured in the presence (problem group) or in the absence (control group) of allografts during 15 days. Allografts produced a decrease in osteoblast proliferation in the first week of the experiment, and an increase in IL6 mRNA, both at 3 h and 2 days, and an increase in the IL6 released to the culture medium the second day of the experiment. We found a decrease in OPG released to the culture on the 2nd and fourth days. These results suggest an increase in bone resorption and a decrease in bone formation in the first week of the experiment. In the second week, allografts produced an increase in osteoblast proliferation and PINP release to the culture medium, indicating an increase in bone formation; an increase in OPG released to the culture medium, which would indicate a decrease in bone resorption; and a decrease in IL6, indicating a decrease in bone resorption stimulation. These results demonstrate that autoclavated and -80 degrees C frozen bone allografts produce in bone environment changes that regulate their own incorporation to the recipient bone.

Gas hydrate formation in the deep sea: In situ experiments with controlled release of methane, natural gas, and carbon dioxide

USGS Publications Warehouse

Brewer, P.G.; Orr, F.M.; Friederich, G.; Kvenvolden, K.A.; Orange, D.L.

1998-01-01

We have utilized a remotely operated vehicle (ROV) to initiate a program of research into gas hydrate formation in the deep sea by controlled release of hydrocarbon gases and liquid CO2 into natural sea water and marine sediments. Our objectives were to investigate the formation rates and growth patterns of gas hydrates in natural systems and to assess the geochemical stability of the reaction products over time. The novel experimental procedures used the carrying capacity, imaging capability, and control mechanisms of the ROV to transport gas cylinders to depth and to open valves selectively under desired P-T conditions to release the gas either into contained natural sea water or into sediments. In experiments in Monterey Bay, California, at 910 m depth and 3.9??C water temperature we find hydrate formation to be nearly instantaneous for a variety of gases. In sediments the pattern of hydrate formation is dependent on the pore size, with flooding of the pore spaces in a coarse sand yielding a hydrate cemented mass, and gas channeling in a fine-grained mud creating a veined hydrate structure. In experiments with liquid CO2 the released globules appeared to form a hydrate skin as they slowly rose in the apparatus. An initial attempt to leave the experimental material on the sea floor for an extended period was partially successful; we observed an apparent complete dissolution of the liquid CO2 mass, and an apparent consolidation of the CH4 hydrate, over a period of about 85 days.

Some comments on interpretations of Viking biological experiments.

PubMed

Aksyonov, S I

1979-07-01

Data from Viking experiments are analyzed from a biological viewpoint. The lack of organic matter in Martian soil could be due to the specificity of regions with optimal landing conditions. All data of labeled release experiments may be explained by assuming the existence of psychrophilic organisms, cultivated at temperatures above optimal ones, and other factors of a biological origin. The biological interpretation does not contradict the results of other life search experiments.

A mRNA-Responsive G-Quadruplex-Based Drug Release System

PubMed Central

Yaku, Hidenobu; Murashima, Takashi; Miyoshi, Daisuke; Sugimoto, Naoki

2015-01-01

G-quadruplex-based drug delivery carriers (GDDCs) were designed to capture and release a telomerase inhibitor in response to a target mRNA. Hybridization between a loop on the GDDC structure and the mRNA should cause the G-quadruplex structure of the GDDC to unfold and release the bound inhibitor, anionic copper(II) phthalocyanine (CuAPC). As a proof of concept, GDDCs were designed with a 10-30-mer loop, which can hybridize with a target sequence in epidermal growth factor receptor (EGFR) mRNA. Structural analysis using circular dichroism (CD) spectroscopy showed that the GDDCs form a (3 + 1) type G-quadruplex structure in 100 mM KCl and 10 mM MgCl2 in the absence of the target RNA. Visible absorbance titration experiments showed that the GDDCs bind to CuAPC with Ka values of 1.5 × 105 to 5.9 × 105 M−1 (Kd values of 6.7 to 1.7 μM) at 25 °C, depending on the loop length. Fluorescence titration further showed that the G-quadruplex structure unfolds upon binding to the target RNA with Ka values above 1.0 × 108 M−1 (Kd values below 0.01 μM) at 25 °C. These results suggest the carrier can sense and bind to the target RNA, which should result in release of the bound drug. Finally, visible absorbance titration experiments demonstrated that the GDDC release CuAPC in response to the target RNA. PMID:25905703

Modelling carbon in permafrost soils from preindustrial to the future

NASA Astrophysics Data System (ADS)

Kleinen, T.; Brovkin, V.

2015-12-01

The carbon release from thawing permafrost soils constitutes one of the large uncertainties in the carbon cycle under future climate change. Analysing the problem further, this uncertainty results from an uncertainty about the total amount of C that is stored in frozen soils, combined with an uncertainty about the areas where soils might thaw under a particular climate change scenario, as well as an uncertainty about the decomposition product since some of the decomposed C might result the release of CH4 as well as CO2. We use the land surface model JSBACH, part of the Max Planck Institute Earth System Model MPI-ESM, to quantify the release of soil carbon from thawing permafrost soils. We have extended the soil carbon model YASSO by introducing carbon storages in frozen soils, with increasing fractions of C being available to decomposition as permafrost thaws. In order to quantify the amount of carbon released as CH4, as opposed to CO2, we have also implemented a TOPMODEL-based wetland scheme, as well as anaerobic C decomposition and methane transport. We initialise the soil C pools for the preindustrial climate state from the Northern Circumpolar Soil Carbon Database to insure initial C pool sizes close to measurements. We then determine changes in soil C storage in transient model experiments following historical and future climate changes under RCP 8.5. Based on these experiments, we quantify the greenhouse gas release from permafrost C decomposition, determining both CH4 and CO2 emissions.

Remediation of metal-contaminated marine sediments using active capping with limestone, steel slag, and activated carbon: a laboratory experiment.

PubMed

Park, Seong-Jik; Kang, Ku; Lee, Chang-Gu; Choi, Jae-Woo

2018-05-18

The objectives of this study are to assess the effectiveness of limestone (LS), steel slag (SS), and activated carbon (AC) as capping materials to sequester trace metals including As, Cd, Cr, Cu, Ni, Pb, and Zn in heavily contaminated marine sediments and to minimize the release of these metals into the water column. A flat flow tank was filled with 10 mm of capping material, contaminated sediments, and seawater, and the metal concentrations were monitored over 32 d. After completion of the flow tank experiments, the sediments below the capping material were sampled and were sequentially extracted. SS effectively reduced the As, Cr, Cu, Ni, Pb, and particularly Cd elution from the contaminated sediments to the overlying seawater. Adsorption and surface precipitation were the key mechanisms for interrupting the release of cationic trace metals by SS. LS was appropriate for interrupting the release of only Cu and Pb with high hydrolysis reaction constants. AC capping could interrupt the release of Cr, Cu, Ni, and particularly Zn from the sediments by binding with the metals via electrostatic interaction. The results obtained from the sequential extraction revealed that LS capping is appropriate for stabilizing Zn, whereas AC is appropriate for Cd and Pb. LS, SS, and AC can be applied effectively for remediation of sediments contaminated by trace metals because it interrupts their release and stabilizes the trace metals in the sediments.

Sustained release effects of berberine-loaded chitosan microspheres on in vitro chondrocyte culture.

PubMed

Zhou, Yan; Liu, Shiqing; Ming, Jianghua; Li, Yaming; Deng, Ming; He, Bin

2017-10-01

The low bioavailability and short biological half-life of berberine chloride (BBR) negatively affect the protective role of this compound against osteoarthritis (OA). The present study was performed to evaluate the effectiveness of sustained BBR release system. Novel BBR-loaded chitosan microspheres (BBR-loaded CMs) were successfully synthesized using an ionic cross-linking method for sustained release. The basic characteristics of the prepared microspheres were subsequently evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) techniques, encapsulation efficiency (EE), and in vitro release experiments. BBR-loaded CMs displayed spherical forms to encapsulate a considerable quantity of BBR (100.8 ± 2.7 mg/g); these microspheres also exhibited an ideal releasing profile. The FT-IR spectra and XRD results revealed that BBR-loaded CMs were successfully synthesized via electrostatic interaction. In vitro experiments further showed that BBR-loaded CMs significantly inhibited sodium nitroprusside (SNP)-stimulated chondrocyte apoptosis as well as cytoskeletal remodeling, and led to increasing mitochondrial membrane potential and maintaining the nuclear morphology. BBR-loaded CMs exerted markedly higher anti-apoptotic activity in the treatment of OA, and markedly inhibited the protein expression levels of caspase-3, a disintegrin, and metalloproteinase with thrombospondin motifs (ADAMTS)-5 and matrix metalloproteinase (MMP)-13 induced by SNP in rat articular chondrocytes, compared with free BBR at equivalent concentration. Therefore, novel BBR-loaded CMs may offer potential for application in the treatment of OA.

Trends in the short-term release of fission products and actinides to aqueous solution from used CANDU fuels at elevated temperature

NASA Astrophysics Data System (ADS)

Stroes-Gascoyne, S.

1992-08-01

A large number of short-term leaching experiments has been performed to determine fission product and actinide release from used CANDU (CANada Deuterium Uranium) fuels and to establish which factors affect release. Results are reported after30 ± 10 d leaching at 100-150°C under oxidizing (air) or reducing (Ar-3% H 2 or Ar) conditions, in various synthetic groundwaters. Cesium-137 release (0.007-6%) was positively correlated with increases in fuel power, leachant temperature and ionic strength. Strontium-90 release (0.0003-0.3%) generally increased with ionic strength, higher temperature and redox conditions. Actinide and Tc concentrations were compared to ranges calculated with a thermodynamic equilibrium model, that accounts for the uncertain geochemical parameters of a nuclear waste vault by calculating concentration ranges based on 40000 hypothetical cases. Experimental U concentrations (10 -8.5 to 10 -3 mol/kg) were higher than the model range, probably because of higher redox potentials in the experiments. Measured Pu concentrations (10 -12.5 to 10 -7 mol/kg) were at the low end of the calculated range. Americium and Cm concentrations (10 -12.5 to 10 -7 and 10 -15 to 10 -9 mol/kg, respectively) were highest under oxidizing conditions and higher temperatures. Technetium-99 concentrations (10 -5.5 to 10 -10.5 mol/kg) covered a much narrower range than calculated by the model.

Characterization of a mine fire using atmospheric monitoring system sensor data

PubMed Central

Yuan, L.; Thomas, R.A.; Zhou, L.

2017-01-01

Atmospheric monitoring systems (AMS) have been widely used in underground coal mines in the United States for the detection of fire in the belt entry and the monitoring of other ventilation-related parameters such as airflow velocity and methane concentration in specific mine locations. In addition to an AMS being able to detect a mine fire, the AMS data have the potential to provide fire characteristic information such as fire growth — in terms of heat release rate — and exact fire location. Such information is critical in making decisions regarding fire-fighting strategies, underground personnel evacuation and optimal escape routes. In this study, a methodology was developed to calculate the fire heat release rate using AMS sensor data for carbon monoxide concentration, carbon dioxide concentration and airflow velocity based on the theory of heat and species transfer in ventilation airflow. Full-scale mine fire experiments were then conducted in the Pittsburgh Mining Research Division’s Safety Research Coal Mine using an AMS with different fire sources. Sensor data collected from the experiments were used to calculate the heat release rates of the fires using this methodology. The calculated heat release rate was compared with the value determined from the mass loss rate of the combustible material using a digital load cell. The experimental results show that the heat release rate of a mine fire can be calculated using AMS sensor data with reasonable accuracy. PMID:28845058

SEDS experiment design definition

NASA Technical Reports Server (NTRS)

Carroll, Joseph A.; Alexander, Charles M.; Oldson, John C.

1990-01-01

The Small Expendable-tether Deployment System (SEDS) was developed to design, build, integrate, fly, and safely deploy and release an expendable tether. A suitable concept for an on-orbit test of SEDS was developed. The following tasks were performed: (1) Define experiment objectives and requirements; (2) Define experiment concepts to reach those objectives; (3) Support NASA in experiment concept selection and definition; (4) Perform analyses and tests of SEDS hardware; (5) Refine the selected SEDS experiment concept; and (6) Support interactive SEDS system definition process. Results and conclusions are given.

Guidance for Evaluating the Safety of Experimental Releases of Mosquitoes, Emphasizing Mark-Release-Recapture Techniques

PubMed Central

Charlwood, J. Derek; Harrington, Laura C.; Lounibos, L. Philip; Reisen, William K.; Tabachnick, Walter J.

2018-01-01

Abstract Experimental releases of mosquitoes are performed to understand characteristics of populations related to the biology, ability to transmit pathogens, and ultimately their control. In this article, we discuss considerations related to the safety of experimental releases of living mosquitoes, applying principles of good practice in vector biology that protect human health and comfort. We describe specific factors of experimental releases of mosquitoes that we believe are critical to inform institutional biosafety committees and similar review boards to which proposals to conduct mosquito release experiments have been submitted. In this study, “experimental releases” means those that do not significantly increase vector capacity or nuisance biting relative to the unperturbed natural baseline. This document specifically does not address releases of mosquitoes for ongoing control programs or trials of new control methods for which broader assessments of risk are required. It also does not address releases of transgenic or exotic (non-native) mosquito species, both of which require particular regulatory approval. Experimental releases may include females and males and evaluation must consider their effects based on the number released, their genotype and phenotype, the environment into which they are released, and postrelease collection activities. We consider whether increases of disease transmission and nuisance biting might result from proposed experimental releases against the backdrop of natural population size variation. We recommend that experimental releases be conducted in a manner that can be reasonably argued to have insignificant negative effects. Reviewers of proposals for experimental releases should expect applicants to provide such an argument based on evidence from similar studies and their planned activities. This document provides guidance for creating and evaluating such proposals. PMID:29337660

Characterization and regulation of (/sup 3/H)-serotonin uptake and release in rodent spinal

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

Stauderman, K.A.

1986-01-01

The uptake and release of (/sup 3/H)-serotonin were investigated in rat spinal cord synaptosomes. In the uptake experiments, sodium-dependent and sodium-independent (/sup 3/H)-serotonin accumulation processes were found. Sodium-dependent (/sup 3/H)-serotonin accumulation was: linear with sodium concentrations up to 180 mM; decreased by disruption of membrane integrity or ionic gradients; associated with purified synaptosomal fractions; and reduced after description of descending serotonergic neurons in the spinal cord. Of the uptake inhibitors tested, the most potent was fluoxetine (IC/sub 50/ 75 nM), followed by desipramine (IC/sub 50/ 430 nM) and nomifensine (IC/sub 50/ 950 nM). The sodium-independent (/sup 3/H)-serotonin accumulation process wasmore » insensitive to most treatments and probably represents nonspecific membrane binding. Thus, only sodium-dependent (/sup 3/H)-serotonin uptake represents the uptake process of serotonergic nerve terminals in rat spinal cord homogenates. In the release experiments, K/sup +/-induced release of previously accumulated (/sup 3/H)-serotonin was Ca/sup 2 +/-dependent, and originated from serotonergic synaptosomes. Exogenous serotonin and 5-methyoxy-N,N-dimethyltryptamine inhibited (/sup 3/H)-serotonin release in a concentration-dependent way. Of the antagonists tested, only methiothepin effectively blocked the effect of serotonin. These data support the existence of presynaptic serotonin autoreceptors on serotonergic nerve terminals in the rat spinal cord that act to inhibit a voltage and Ca/sup 2 +/-sensitive process linked to serotonin release. Alteration of spinai cord serotonergic function may therefore be possible by drugs acting on presynaptic serotonin autoreceptors in the spinal cord.« less

Metal ion release from metallothioneins: proteolysis as an alternative to oxidation.

PubMed

Peroza, Estevão A; dos Santos Cabral, Augusto; Wan, Xiaoqiong; Freisinger, Eva

2013-09-01

Metallothioneins (MTs) are among others involved in the cellular regulation of essential Zn(II) and Cu(I) ions. However, the high binding affinity of these proteins requires additional factors to promote metal ion release under physiological conditions. The mechanisms and efficiencies of these processes leave many open questions. We report here a comprehensive analysis of the Zn(II)-release properties of various MTs with special focus on members of the four main subfamilies of plant MTs. Zn(II) competition experiments with the metal ion chelator 4-(2-pyridylazo)resorcinol (PAR) in the presence of the cellular redox pair glutathione (GSH)/glutathione disulfide (GSSG) show that plant MTs from the subfamilies MT1, MT2, and MT3 are remarkably more affected by oxidative stress than those from the Ec subfamily and the well-characterized human MT2 form. In addition, we evaluated proteolytic digestion with trypsin and proteinase K as an alternative mechanism for selective promotion of metal ion release from MTs. Also here the observed percentage of liberated metal ions depends strongly on the MT form evaluated. Closer evaluation of the data additionally allowed deducing the thermodynamic and kinetic properties of the Zn(II) release processes. The Cu(I)-form of chickpea MT2 was used to exemplify that both oxidation and proteolysis are also effective ways to increase the transfer of copper ions to other molecules. Zn(II) release experiments with the individual metal-binding domains of Ec-1 from wheat grain reveal distinct differences from the full-length protein. This triggers the question about the roles of the long cysteine-free peptide stretches typical for plant MTs.

Water- and Fertilizer-Integrated Hydrogel Derived from the Polymerization of Acrylic Acid and Urea as a Slow-Release N Fertilizer and Water Retention in Agriculture.

PubMed

Cheng, Dongdong; Liu, Yan; Yang, Guiting; Zhang, Aiping

2018-05-31

To reduce the preparation cost of superabsorbent and improve the N release rate at the same time, a novel low-cost superabsorbent (SA) with the function of N slow release was prepared by chemical synthesis with neutralized acrylic acid (AA), urea, potassium persulfate (KPS), and N, N'-methylenebis(acrylamide) (MBA). The order of influence factors on the water absorbency property was determined by an orthogonal L 18 (3) 7 experiment. On the basis of the optimization results of the orthogonal experiment, the effects of a single factor on the water absorption were investigated, and the highest water absorbency (909 g/g) was achieved for the conditions of 1.0 mol urea/mol AA ratio, 100% of AA neutralized, K + , 1.5% KPS to AA mass fraction, 0.02% MBA to AA mass fraction, 45 °C reaction temperature, and 4.0 h reaction time. The optimal sample was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Swelling behaviors of the superabsorbent were investigated in distilled water and various soil and salt solutions. The water-release kinetics of SA in different negative pressures and soils were systematically investigated. Additionally, the maize seed germination in various types of soil with different amounts of SA was proposed, and the N could release 3.71% after being incubated in distilled water for 40 days. After 192 h, the relative water content of SA-treated sandy loam, loam, and paddy soil were 42, 56, and 45%, respectively. All of the results in this work showed that SA had good water retention and slow N-release properties, which are expected to have potential applications in sustainable modern agriculture.

Aerosolization of Particulate (1→3)-β-d-Glucan from Moldy Materials▿

PubMed Central

Seo, Sung-Chul; Reponen, Tiina; Levin, Linda; Borchelt, Tiffany; Grinshpun, Sergey A.

2008-01-01

Mold-damaged building materials may contain biologically active agents, such as (1→3)-β-d-glucan, allergens, and mycotoxins, which have been associated with adverse health effects. The release of these components from contaminated surfaces into the air is not well understood. The purpose of this study was to characterize the release of particulate (1→3)-β-d-glucan from the surface of artificially mold-contaminated materials. Aspergillus versicolor and Stachybotrys chartarum were grown on malt extract agar (MEA), white ceiling tiles, and a wall-papered gypsum board for 1 and 6 months. The (1→3)-β-d-glucan on the surfaces of moldy materials and in air samples collected from these materials was analyzed by the Limulus amebocyte lysate assay. The aerosolization ratio was defined as the amount of (1→3)-β-d-glucan in the air divided by the amount on the surface. The results showed that the aerosolization of particulate (1→3)-β-d-glucan was influenced mainly by the type of material and the fungal species. For A. versicolor, the aerosolization ratios of particulate (1→3)-β-d-glucan released from the three types of material were not significantly different. However, the ratios for S. chartarum released from ceiling tiles and gypsum board were significantly higher than the ratios for this organism released from MEA (P < 0.001) and were comparable to those for A. versicolor. These findings indicate that the use of MEA in aerosolization experiments is likely to underestimate the release of S. chartarum particles from building materials. These results provide important background information for design of future laboratory or animal experiments, as well as for interpretation of field measurement data. PMID:18065630

Behavior of TiO₂ nanoparticles during incineration of solid paint waste: a lab-scale test.

PubMed

Massari, Andrea; Beggio, Marta; Hreglich, Sandro; Marin, Riccardo; Zuin, Stefano

2014-10-01

In order to assess the potential impacts posed by products containing engineered nanoparticles, it is essential to generate more data about the release of these particles from products' life cycle. Although first studies were performed to investigate the release of nanoparticles from use phase, very few data are available on the potential release from recycling or disposal of nano-enhanced products. In this work, we investigated the behavior of TiO2 nanoparticles from incineration of solid paint waste containing these particles. Solid paint debris with and without TiO2 nanoparticles were treated in a lab scale incineration plant at 950°C (combustion temperature) and in oxidizing atmosphere. The obtained ashes were also vitrified with additives and the release of Ti was finally evaluated by leaching test. From our incineration lab-scale experiment, we did not observe a release of TiO2 nanoparticles into the atmosphere, and Ti was attached to the surface of obtained solid residues (i.e. ashes). The characterization of ashes showed that TiO2 nanoparticles reacted during the incineration to give calcium titanate. Finally, a very low release of Ti was measured, less 1 mg/kg, during the leaching test of ashes vitrified with glass cullet and feldspathic inert. Our work suggests that TiO2 nanoparticles added in paints may undergo to physicochemical transformation during the incineration, and that Ti found in ashes may be strongly immobilized in glass matrix. Since this conclusion is based on lab-scale experiment, further research is required to identify which nanoparticles will be emitted to the environment from a real-word-incineration system of household hazardous waste. Copyright © 2014 Elsevier Ltd. All rights reserved.

The mast cell stabilizer sodium cromoglycate reduces histamine release and status epilepticus-induced neuronal damage in the rat hippocampus.

PubMed

Valle-Dorado, María Guadalupe; Santana-Gómez, César Emmanuel; Orozco-Suárez, Sandra Adela; Rocha, Luisa

2015-05-01

Experiments were designed to evaluate changes in the histamine release, mast cell number and neuronal damage in hippocampus induced by status epilepticus. We also evaluated if sodium cromoglycate, a stabilizer of mast cells with a possible stabilizing effect on the membrane of neurons, was able to prevent the release of histamine, γ-aminobutyric acid (GABA) and glutamate during the status epilepticus. During microdialysis experiments, rats were treated with saline (SS-SE) or sodium cromoglycate (CG-SE) and 30 min later received the administration of pilocarpine to induce status epilepticus. Twenty-four hours after the status epilepticus, the brains were used to determine the neuronal damage and the number of mast cells in hippocampus. During the status epilepticus, SS-SE group showed an enhanced release of histamine (138.5%, p = 0.005), GABA (331 ± 91%, p ≤ 0.001) and glutamate (467%, p ≤ 0.001), even after diazepam administration. One day after the status epilepticus, SS-SE group demonstrated increased number of mast cells in Stratum pyramidale of CA1 (88%, p < 0.001) and neuronal damage in dentate gyrus, CA1 and CA3. In contrast to SS-SE group, rats from the CG-SE group showed increased latency to the establishment of the status epilepticus (p = 0.048), absence of wet-dog shakes, reduced histamine (but not GABA and glutamate) release, lower number of mast cells (p = 0.008) and reduced neuronal damage in hippocampus. Our data revealed that histamine, possibly from mast cells, is released in hippocampus during the status epilepticus. This effect may be involved in the subsequent neuronal damage and is diminished with sodium cromoglycate pretreatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

In vivo release of non-neuronal acetylcholine from the human skin as measured by dermal microdialysis: effect of botulinum toxin

PubMed Central

Schlereth, Tanja; Birklein, Frank; Haack, Katrin an; Schiffmann, Susanne; Kilbinger, Heinz; Kirkpatrick, Charles James; Wessler, Ignaz

2005-01-01

Acetylcholine is synthesized in the majority of non-neuronal cells, for example in human skin. In the present experiments, the in vivo release of acetylcholine was measured by dermal microdialysis. Two microdialysis membranes were inserted intradermally at the medial shank of volunteers. Physiological saline containing 1 μM neostigmine was perfused at a constant rate of 4 μl min−1 and the effluent was collected in six subsequent 20 min periods. Acetylcholine was measured by high-pressure liquid chromatography (HPLC) combined with bioreactors and electrochemical detection. Analysis of the effluent by HPLC showed an acetylcholine peak that disappeared, when the analytical column was packed with acetylcholine-specific esterase, confirming the presence of acetylcholine. In the absence of neostigmine, 71±51 pmol acetylcholine (n=4) was found during a 120 min period. The amount increased to 183±43 pmol (n=34), when the perfusion medium contained 1 μM neostigmine. Injection of 100 MU botulinum toxin subcutaneously blocked sweating completely, but the release of acetylcholine was not affected (botulinum toxin treated skin: 116±70 pmol acetylcholine/120 min; untreated skin: 50±20 pmol; n=4). Quinine (1 mM), inhibitor of organic cation transporters, and carnitine (0.1 mM), substrate of the Na+-dependent carnitine transporter OCTN2, tended to reduce acetylcholine release (by 40%, not significant). Our experiments demonstrate, for the first time, the in vivo release of non-neuronal acetylcholine in human skin. Organic cation transporters are not predominantly involved in the release of non-neuronal acetylcholine from the human skin. PMID:16273117

Exposure Assessment of a High-energy Tensile Test With Large Carbon Fiber Reinforced Polymer Cables.

PubMed

Schlagenhauf, Lukas; Kuo, Yu-Ying; Michel, Silvain; Terrasi, Giovanni; Wang, Jing

2015-01-01

This study investigated the particle and fiber release from two carbon fiber reinforced polymer cables that underwent high-energy tensile tests until rupture. The failing event was the source of a large amount of dust whereof a part was suspected to be containing possibly respirable fibers that could cause adverse health effects. The released fibers were suspected to migrate through small openings to the experiment control room and also to an adjacent machine hall where workers were active. To investigate the fiber release and exposure risk of the affected workers, the generated particles were measured with aerosol devices to obtain the particle size and particle concentrations. Furthermore, particles were collected on filter samples to investigate the particle shape and the fiber concentration. Three situations were monitored for the control room and the machine hall: the background concentrations, the impact of the cable failure, and the venting of the exposed rooms afterward. The results showed four important findings: The cable failure caused the release of respirable fibers with diameters below 3 μm and an average length of 13.9 μm; the released particles did migrate to the control room and to the machine hall; the measured peak fiber concentration of 0.76 fibers/cm(3) and the overall fiber concentration of 0.07 fibers/cm(3) in the control room were below the Permissible Exposure Limit (PEL) for fibers without indication of carcinogenicity; and the venting of the rooms was fast and effective. Even though respirable fibers were released, the low fiber concentration and effective venting indicated that the suspected health risks from the experiment on the affected workers was low. However, the effect of long-term exposure is not known therefore additional control measures are recommended.

Understanding Cu release into environment from Kure massive sulfide ore deposits, Kastamonu, NW Turkey

NASA Astrophysics Data System (ADS)

Demirel, Cansu; Sonmez, Seref; Balci, Nurgul

2014-05-01

Covering a wide range on the earth's crust, oxidation of metal sulfide minerals have vital environmental impacts on the aquatic environment, causing one of the major environmental problems known as acid mine drainage (AMD). Located in the Kastamonu province of the Western Black Sea region, Kure district is one of the major copper mining sites in Turkey. Mining activities in the area heads back to ancient times, such that operation is thought to be started with the Roman Empire. Currently, only the underground mining tunnels of Bakibaba and Asikoy are being operated. Thus, mining heaps and ores of those pyritic deposits have been exposed to the oxidative conditions for so long. As a result of weathering processes of past and recent heaps of the Kure volcanic massive sulfide deposits in addition to the main ore mineral (chalcopyrite), significant amount of metals, especially Cu, are being released into the environment creating undesirable environmental conditions. In order to elucidate Cu release mechanisms from Kure pyritic ore deposits and mining wastes, field and laboratory approaches were used. Surface water and sediment samples from the streams around the mining and waste sites were collected. Groundwater samples from the active underground mining site were also collected. Physical parameters (pH, Eh, T°C, and EC) of water samples were determined in situ and in the laboratory using probes (WTW pH 3110, WTW Multi 9310 and CRISON CM 35). Metal and ion concentrations of the water samples were analysed using ICP-MS and DR 2800 spectrophotometer, respectively. High Cu, Co, Zn and Fe concentrations were determined in the water samples with pH values ranging from 2.9- 4. Cu concentrions ranges from 345 ppm to 36 ppm in the water samples. Consistent with the water samples, high Cu, Fe, Zn and Co were also determined in the sediment samples. Laboratory chalcopyrite oxidation experiments under the conditions representing the field site were set up as biological and abiotic in order to elucidate Cu release from ore and wastes. Greater Cu release were measured from the biological experiments carried out with S and Fe oxidizers compared to those from the chemical experiments. Fe-oxide precipitation experiments carried out in the laboratory showed high Cu absorbtion into Fe-oxides produced by biological reactions carried out with Fe oxidizers. Overall, these preliminary experimental results showed that Cu release and migration from the source can be controlled by various microorganims which regulate S and Fe cycles in the field. Key words: Metal sulfide oxidation, Kure pyritic copper mines, AMD, Bioleaching, Secondary Fe-oxide precipitation

An airborne perfluorocarbon tracer system and its first application for a Lagrangian experiment

NASA Astrophysics Data System (ADS)

Ren, Y.; Baumann, R.; Schlager, H.

2015-01-01

A perfluorocarbon tracer system (PERTRAS), specifically designed for Lagrangian aircraft experiments, has been developed by the Deutsches Zentrum für Luft- und Raumfahrt (German Aerospace Center, DLR). It consists of three main parts: a tracer release unit (RU), an adsorption tube sampler (ATS), and a tracer analytical system. The RU was designed for airborne tracer release experiments; meanwhile, it can be used on various platforms for different experimental purposes (here research vessel). PERTRAS was for the first time applied in the field campaign Stratospheric ozone: Halogen Impacts in a Varying Atmosphere (SHIVA) in November 2011. An amount of 8.8 kg perfluoromethylcyclopentane (PMCP) was released aboard the research vessel Sonne (RV Sonne) near the operational site of this campaign, Miri, Malaysia, on 21 November. The tracer samples collected using the ATS onboard the DLR research aircraft Falcon were analyzed in the laboratory using a thermal desorber-gas chromatography-mass spectrometry (TD-GC-MS) system. Guided by forecasts calculated with the Lagrangian model Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT), 64 tracer samples were collected onboard the Falcon approximately 5 and 25 h after the release, mostly with a time resolution of 1 min. Enhanced PMCP concentrations relative to ambient PMCP background values (mean: 6.62 fmol mol-1) were detected during three intersects of the fresh tracer plume (age 5 h), with a maximum value of 301.33 fmol mol-1. This indicates that the fresh tracer plume was successfully intercepted at the forecast position. During the second flight, 25 h after the release, the center of tracer plume was not detected by the sampling system due to a faster advection of the plume than forecast. The newly developed PERTRAS system has been successfully deployed for the first time. The instrumental setup and comparisons between the measurements and HYSPLIT simulations are presented in this study.

An airborne perfluorocarbon tracer system and its first application for a Lagrangian experiment

NASA Astrophysics Data System (ADS)

Ren, Y.; Baumann, R.; Schlager, H.

2014-07-01

A perfluorocarbon tracer system (PERTRAS), specifically designed for Lagrangian aircraft experiments, has been developed by the Deutsches Zentrum für Luft- und Raumfahrt (German Aerospace Center, DLR). It consists of three main parts: a tracer release unit (RU), an adsorption tube sampler (ATS) and a tracer analytical system. The RU was designed for airborne tracer release experiments; meanwhile, it can be used on various platforms for different experimental purpose (here research vessel). PERTRAS was for the first time applied in the field campaign Stratospheric ozone: halogen Impacts in a Varying Atmosphere (SHIVA) in November 2011. An amount of 8.8 kg perfluoromethylcyclopentane (PMCP) was released aboard the research vessel Sonne (RV Sonne) near the operational site of this campaign, Miri, Malaysia, on 21 November. The tracer samples collected using the ATS on board the DLR research aircraft Falcon were analyzed in the laboratory using a thermal desorber/gas chromatography/mass spectrometry (TD/GC/MS) system. Guided by forecasts calculated with the Lagrangian model, Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT), 64 tracer samples were collected onboard the Falcon approximately 5 and 25 h after the release, respectively, mostly with a time resolution of 1 min. Enhanced PMCP concentrations relative to ambient PMCP background values (mean: 6.62 fmol mol-1) were detected during three intersects of the fresh tracer plume (age 5 h), with a maximum value of 301.33 fmol mol-1. This indicates that the fresh tracer plume was successfully intercepted at the forecasted position. During the second flight, 25 h after the release, the center of tracer plume was not detected by the sampling system due to a faster advection of the plume than forecasted. The newly developed PERTRAS system has been successfully deployed for the first time. The instrumental set-up and comparisons between the measurements and HYSPLIT simulations are presented in this study.

[Anti-tumor effect of 5-FU-PLLA-CNTs on human gastric carcinoma cell lines in vitro].

PubMed

Gu, Jun; Li, Maolan; Wu, Xiangsong; Wu, Wenguang; Zhang, Lin; Ding, Qichen; Yang, Jiahua; Weng, Hao; Ding, Qian; Bao, Runfa; Shu, Yijun; Liu, Yingbin

2014-04-01

To prepare cisPLLAtin-loaded polylactic acid/cnts, and to study the anti-tumor effect of 5-FU-PLLA-CNTs on human gastric carcinoma cell lines(MGC803 and MNK45). 5-FU-PLLA-CNTs were prepared with ultrasound emulsification. The morphology of 5-FU-PLLA-CNTs was determined by scanning electron microscope(SEM), and its drug loading and drug release curve in vitro were detected by UV-Vis-NIR spectrophotometer. Cells were divided into experiment, positive control and negative control groups. CCK8 method was used to test the cytotoxic effect of 5-FU-PLLA-CNTs in different concentrations on MGC803 and MNK45 cell proliferation. Flow cytometry was employed to measure the apoptotic rate of MGC803 and MNK45 cells before and after the intervention of 5-FU-PLLA-CNTs. Deep layer film of 5-FU-PLLA-CNTs was successfully established, whose drug-load rate was(4.54±0.43)%, entrapment rate was(21.56±2.36)%. In vitro release test showed release rate within 24 h of 5-FU-PLLA-CNTs was 23.9% in a as lowly increasing manner, and accumulating release rate was 85.3% at day 31. CCk8 experiment revealed, as compared to control group, 5-FU-PLLA-CNTs significantly inhibited the proliferation of two cell lines in dose-dependent and time-dependent manner. The best 5-FU-PLLA-CNTs concentration of inhibition for human gastric cancer cell lines was 1 mg/well. Flow cytometry indicated the apoptotic rate of MGC803 and MNK45 cells in experiment group treated by 1 mg/well 5-FU-PLLA-CNTs significantly increased as compared to negative control group (P<0.05), while the difference was not significant as compared to positive control group (P>0.05). The 5-FU-PLLA-CNTs has good drug sustained-release capacity, and can significantly kill and inhibit the proliferation of MGC803 and MNK45 cell lines.

An exploratory study of reiki experiences in women who have cancer.

PubMed

Kirshbaum, Marilynne N; Stead, Maxine; Bartys, Serena

2016-04-02

To explore the perceptions and experiences of reiki for women who have cancer and identify outcome measures for an intervention study. A cross-sectional qualitative study of 10 women who had received reiki after cancer treatment was conducted. Interviews were audiotaped, transcribed and coded using framework analysis. Key themes identified were: limited understanding of reiki prior to receiving any reiki; release of emotional strain during reiki-feelings of a release of energy, a clearing of the mind from cancer, inner peace/relaxation, hope, a sense of being cared for; experience of physical sensations during reiki, such as pain relief and tingling; physical, emotional and cognitive improvements after reiki, such as improved sleep, a sense of calm and peace, reduced depression and improved self-confidence. Findings suggest that reiki could be a beneficial tool in the self-management of quality of life issues for women who have cancer.

One-step synthesis of magnetic chitosan for controlled release of 5-hydroxytryptophan

NASA Astrophysics Data System (ADS)

Santos Menegucci, Jucély dos; Santos, Mac-Kedson Medeiros Salviano; Dias, Diego Juscelino Santos; Chaker, Juliano Alexandre; Sousa, Marcelo Henrique

2015-04-01

In this work, nanoparticles of chitosan embedded with 25% (w/w) of iron oxide magnetic nanoparticles (magnetite/maghemite) with narrow size-distribution and with a loading efficiency of about 80% for 5-hydroxytryptophan (5-HTP), which is a chemical precursor in the biosynthesis of important neurotransmitters as serotonin, were synthesized with an initial mass ratio of 5-HTP/magnetic chitosan=1.2, using homogeneous precipitation by urea decomposition, in an efficient one-step procedure. Characterization of morphology, structure and surface were performed by XRD, TEM, FTIR, TGA, magnetization and zeta potential measurements, while drug loading and drug releasing were investigated using UV-vis spectroscopy. Kinetic drug release experiments under different pH conditions revealed a pH-sensitivecontrolled-release system, ruled by polymer swelling and/or particle dissolution.

Primary system fission product release and transport: A state-of-the-art report to the committee on the safety of nuclear installations

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

Wright, A.L.

This report presents a summary of the status of research activities associated with fission product behavior (release and transport) under severe accident conditions within the primary systems of water-moderated and water-cooled nuclear reactors. For each of the areas of fission product release and fission product transport, the report summarizes relevant information on important phenomena, major experiments performed, relevant computer models and codes, comparisons of computer code calculations with experimental results, and general conclusions on the overall state of the art. Finally, the report provides an assessment of the overall importance and knowledge of primary system release and transport phenomena andmore » presents major conclusions on the state of the art.« less

Preparation and Drug-Delivery Properties of HKUST-1/GO Hybrid.

PubMed

Sun, Ke Ke; Li, Ling; He, Yu Qi; Fan, Lu; Wu, Ya Qi; Liu, Li

2016-01-01

A hybrid HKUST-1/GO composite was synthesized and its drug loading and drug release abilities were investigated. The adsorption of IBU (ibuprofen) onto the surface of HKUST-1/GO and HKUST-1 composites was compared, and it was found that the addition of GO enhanced both IBU loading and stability. The addition of GO also enhanced the specific surface area. Drug release experiments on IBU loaded HKUST-1 and HKUST-1/GO were conducted, and it was found that drug release of HKUST-1/GO was slower, which can be explained by the hydrogen bonding between GO and IBU. It can be concluded that the addition of GO not only enhances drug loading, but can also achieve a more desirable slow-release of the drug.

Particle Release Experiment (PRex) Final Report

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

Keillor, Martin E.; Arrigo, Leah M.; Detwiler, Rebecca S.

2014-09-30

An experiment to release radioactive particles representative of small-scale venting from an underground nuclear test was conducted to gather data in support of treaty verification and monitoring activities. For this experiment, a CO 2-driven “air cannon” was used to release La-140 at ambient temperatures. Lanthanum-140 was chosen to represent the fission fragments because of its short half-life and prominent gamma-ray emissions; the choice was also influenced by the successful production and use of La-140 with low levels of radioactive contaminants in a Defence Research and Development Canada Field Trial. The source was created through activation of high-purity natural lanthanum oxidemore » at the reactor of Washington State University, Pullman, Washington. Multiple varieties of witness plates and air samplers were laid in an irregular grid covering the area over which the plume was modeled to deposit. Aerial survey, a NaI(Tl) mobile spectrometer, and handheld and backpack instruments ranging from polyvinyl toluene to high-purity germanium were used to survey the plume. Additionally, three varieties of soil sampling were investigated. The relative sensitivity and utility of sampling and survey methods are discussed in the context of On-Site Inspection. The measurements and samples show a high degree of correlation and form a valuable set of test data.« less

Shift in Mass Transfer of Wastewater Contaminants from Microplastics in the Presence of Dissolved Substances.

PubMed

Seidensticker, Sven; Zarfl, Christiane; Cirpka, Olaf A; Fellenberg, Greta; Grathwohl, Peter

2017-11-07

In aqueous environments, hydrophobic organic contaminants are often associated with particles. Besides natural particles, microplastics have raised public concern. The release of pollutants from such particles depends on mass transfer, either in an aqueous boundary layer or by intraparticle diffusion. Which of these mechanisms controls the mass-transfer kinetics depends on partition coefficients, particle size, boundary conditions, and time. We have developed a semianalytical model accounting for both processes and performed batch experiments on the desorption kinetics of typical wastewater pollutants (phenanthrene, tonalide, and benzophenone) at different dissolved-organic-matter concentrations, which change the overall partitioning between microplastics and water. Initially, mass transfer is externally dominated, while finally, intraparticle diffusion controls release kinetics. Under boundary conditions typical for batch experiments (finite bath), desorption accelerates with increasing partition coefficients for intraparticle diffusion, while it becomes independent of partition coefficients if film diffusion prevails. On the contrary, under field conditions (infinite bath), the pollutant release controlled by intraparticle diffusion is not affected by partitioning of the compound while external mass transfer slows down with increasing sorption. Our results clearly demonstrate that sorption/desorption time scales observed in batch experiments may not be transferred to field conditions without an appropriate model accounting for both the mass-transfer mechanisms and the specific boundary conditions at hand.

The flexibility of a distant loop modulates active site motion and product release in ribonuclease A.

PubMed

Doucet, Nicolas; Watt, Eric D; Loria, J Patrick

2009-08-04

The role of the flexible loop 1 in protein conformational motion and in the dissociation of enzymatic product from ribonuclease A (RNase A) was investigated by creation of a chimeric enzyme in which a 6-residue loop 1 from the RNase A homologue, eosinophil cationic protein (ECP), replaced the 12-residue loop 1 in RNase A. The chimera (RNase A(ECP)) experiences only local perturbations in NMR backbone chemical shifts compared to WT RNase A. Many of the flexible residues that were previously identified in WT as involved in an important conformational change now experience no NMR-detected millisecond motions in the chimera. Likewise, binding of the product analogue, 3'-CMP, to RNase A(ECP) results in only minor chemical shift changes in the enzyme similar to what is observed for the H48A mutant of RNase A and in contrast to WT enzyme. For both RNase A(ECP) and H48A there is a 10-fold decrease in the product release rate constant, k(off), compared to WT, in agreement with previous studies indicating the importance of flexibility in RNase A in the overall rate-limiting product release step. Together, these NMR and biochemical experiments provide additional insight into the mechanism of millisecond motions in the RNase A catalytic cycle.

The Cross Surfzone/Inner-shelf Dye Exchange (CSIDE) Experiment Overview: Binational Dye Tracer Releases to Study Pollution Transport and Dilution.

NASA Astrophysics Data System (ADS)

Feddersen, F.; Giddings, S. N.; Kumar, N.; Grimes, D. J.; Pawlak, G. R.; Rivas, D.; Diaz, M.

2016-02-01

Per square km, the surfzone and inner-shelf are by far the most economically and ecologically important ocean regions, vital for recreation, food, and ecosystem services. Despite the importance of clean coastal waters to our economy and well-being, declining water quality threatens coastal ecosystem and human health worldwide. Healthy coasts are a significant priority to federal agencies, local government, and NGOs. In particular the San Diego US and Tijuana Mexico border region have unique and persistent water quality issues due to a range of pollution sources. Cross-shore exchange of tracers (e.g., pathogens, anthropogenic nutrients, harmful algal blooms - HABs, larvae) between the well-mixed surfzone and stratified inner-shelf is poorly understood. The surfzone, inner- and mid-shelf span drastically different dynamical regimes, with varying cross-shelf exchange mechanisms due to wave, wind, buoyancy, and tidal processes and intrinsic variability. The NSF funded CSIDE (Cross Surfzone/Inner-shelf Dye Exchange) experiment (Sept & Oct 2015) aims to increase our understanding of cross-shelf material exchange by performing 3 shoreline dye release experiments that are tracked for up to 20 km alongshore and over 48+ hrs. One dye release will be performed in Mexico and the dye transport tracked across the border. The dye will be tracked via a broad range of binational instrumentation. In this presentation, we present an overview of the CSIDE experiment, in particular the binational aspects of the study,

NORSE2015 - A Focused Experiment On Oil Emulsion Characterization Using PolSAR During the 2015 Norwegian Oil-On-Water Exercise

NASA Astrophysics Data System (ADS)

Holt, B.; Jones, C. E.; Brekke, C.; Breivik, O.; Skrunes, S.; Espeseth, M.

2016-02-01

A targeted experiment in characterizing the properties and development of mineral oil slicks was undertaken by NASA, UiT - The Arctic University of Norway, and the Norwegian Meteorological Institute during the 2015 Norwegian oil-on-water spill exercise in the North Sea (OPV2015). NORSE2015 (Norwegian Radar oil Spill Experiment) involved controlled release of plant oil and mineral emulsions of three different oil-to-water ratios, imaging of the slicks with satellite-borne synthetic aperture radars (SAR), and tracking their development with the NASA-UAVSAR instrument over a period of eight hours following release. During the experiment, in situ measurements were made from ship or aircraft with meteorological instruments, released drift buoys, and optical/IR imagers. The experiment was designed to provide validation data for development of a physical model relating polarization-dependent electromagnetic scattering to the dielectric properties of oil mixed with ocean water in a thick slick or emulsion. UAVSAR is a particularly low noise instrument, which enables detection of oil characteristics, and serves as the basis for a relative comparison of different radar frequencies and instruments in oil slick detection and characterization. The time series of UAVSAR polarimetric SAR (PolSAR) is used to track the spreading, movement, and change in backscatter of the different emulsion slicks and the plant oil, to look at movement relative to wind and wave directions, and to develop methods to differentiate between biogenic and mineral slicks based upon temporal changes in the slicks, including environment-driven changes. In this presentation, the experiment will be described and preliminary results presented. This work was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. The Norwegian experiment was partly financed by CIRFA - Centre for integrated remote sensing and forecasting for arctic operations.

Financial Analysis of Experimental Releases Conducted at Glen Canyon Dam during Water Year 2015

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

Graziano, D. J.; Poch, L. A.; Veselka, T. D.

This report examines the financial implications of experimental flows conducted at the Glen Canyon Dam (GCD) in water year (WY) 2015. It is the seventh report in a series examining the financial implications of experimental flows conducted since the Record of Decision (ROD) was adopted in February 1997 (Reclamation 1996). A report released in January 2011 examined WYs 1997 to 2005 (Veselka et al. 2011); a report released in August 2011 examined WYs 2006 to 2010 (Poch et al. 2011); a report released June 2012 examined WY 2011 (Poch et al. 2012); a report released April 2013 examined WY 2012more » (Poch et al. 2013); a report released June 2014 examined WY 2013 (Graziano et al. 2014); and a report released September 2015 examined WY 2014 (Graziano et al. 2015). An experimental release may have either a positive or negative impact on the financial value of energy production. Only one experimental release was conducted at GCD in WY 2015; specifically, a high flow experimental (HFE) release conducted in November 2014. For this experimental release, financial costs of approximately $2.1 million were incurred because the HFE required sustained water releases that exceeded the powerplant’s maximum flow rate. In addition, during the month of the experiment, operators were not allowed to shape GCD power production to either follow firm power customer loads or to respond to market prices. This study identifies the main factors that contribute to HFE costs and examines the interdependencies among these factors. It applies an integrated set of tools to estimate financial impacts by simulating the GCD operations under two scenarios: (1) a baseline scenario that mimics both HFE operations during the experiment and during the rest of the year when it complies with the 1996 ROD operating criteria, and (2) a “without experiments” scenario that is identical to the baseline except it assumes that the HFE did not occur. The Generation and Transmission Maximization (GTMax) model was the main simulation tool used to simulate the dispatch of hydropower plants at GCD and other plants that comprise the Salt Lake City Area Integrated Projects (SLCA/IP). The research team used extensive data sets and historical information on SLCA/IP powerplant characteristics, hydrologic conditions, and Western Area Power Administration’s (WAPA’s) power purchase prices in the modeling process. In addition to estimating the financial impact of the HFE, the team used the GTMax model to gain insights into the interplay among ROD operating criteria, exceptions that were made to criteria to accommodate the experimental releases, and WAPA operating practices.« less

Model-Based Optimal Experimental Design for Complex Physical Systems

DTIC Science & Technology

2015-12-03

for public release. magnitude reduction in estimator error required to make solving the exact optimal design problem tractable. Instead of using a naive...for designing a sequence of experiments uses suboptimal approaches: batch design that has no feedback, or greedy ( myopic ) design that optimally...approved for public release. Equation 1 is difficult to solve directly, but can be expressed in an equivalent form using the principle of dynamic programming

Reduction of Phosphorylated Synapsin I (Ser-553) Leads to Spatial Memory Impairment by Attenuating GABA Release after Microwave Exposure in Wistar Rats

PubMed Central

Qiao, Simo; Peng, Ruiyun; Yan, Haitao; Gao, Yabing; Wang, Changzhen; Wang, Shuiming; Zou, Yong; Xu, Xinping; Zhao, Li; Dong, Ji; Su, Zhentao; Feng, Xinxin; Wang, Lifeng; Hu, Xiangjun

2014-01-01

Background Abnormal release of neurotransmitters after microwave exposure can cause learning and memory deficits. This study investigated the mechanism of this effect by exploring the potential role of phosphorylated synapsin I (p-Syn I). Methods Wistar rats, rat hippocampal synaptosomes, and differentiated (neuronal) PC12 cells were exposed to microwave radiation for 5 min at a mean power density of 30 mW/cm2. Sham group rats, synaptosomes, and cells were otherwise identically treated and acted as controls for all of the following post-exposure analyses. Spatial learning and memory in rats was assessed using the Morris Water Maze (MWM) navigation task. The protein expression and presynaptic distribution of p-Syn I and neurotransmitter transporters were examined via western blotting and immunoelectron microscopy, respectively. Levels amino acid neurotransmitter release from rat hippocampal synaptosomes and PC12 cells were measured using high performance liquid chromatograph (HPLC) at 6 hours after exposure, with or without synapsin I silencing via shRNA transfection. Results In the rat experiments, there was a decrease in spatial memory performance after microwave exposure. The expression of p-Syn I (ser-553) was decreased at 3 days post-exposure and elevated at later time points. Vesicular GABA transporter (VGAT) was significantly elevated after exposure. The GABA release from synaptosomes was attenuated and p-Syn I (ser-553) and VGAT were both enriched in small clear synaptic vesicles, which abnormally assembled in the presynaptic terminal after exposure. In the PC12 cell experiments, the expression of p-Syn I (ser-553) and GABA release were both attenuated at 6 hours after exposure. Both microwave exposure and p-Syn I silencing reduced GABA release and maximal reduction was found for the combination of the two, indicating a synergetic effect. Conclusion p-Syn I (ser-553) was found to play a key role in the impaired GABA release and cognitive dysfunction that was induced by microwave exposure. PMID:24743689

Reduction of phosphorylated synapsin I (ser-553) leads to spatial memory impairment by attenuating GABA release after microwave exposure in Wistar rats.

PubMed

Qiao, Simo; Peng, Ruiyun; Yan, Haitao; Gao, Yabing; Wang, Changzhen; Wang, Shuiming; Zou, Yong; Xu, Xinping; Zhao, Li; Dong, Ji; Su, Zhentao; Feng, Xinxin; Wang, Lifeng; Hu, Xiangjun

2014-01-01

Abnormal release of neurotransmitters after microwave exposure can cause learning and memory deficits. This study investigated the mechanism of this effect by exploring the potential role of phosphorylated synapsin I (p-Syn I). Wistar rats, rat hippocampal synaptosomes, and differentiated (neuronal) PC12 cells were exposed to microwave radiation for 5 min at a mean power density of 30 mW/cm2. Sham group rats, synaptosomes, and cells were otherwise identically treated and acted as controls for all of the following post-exposure analyses. Spatial learning and memory in rats was assessed using the Morris Water Maze (MWM) navigation task. The protein expression and presynaptic distribution of p-Syn I and neurotransmitter transporters were examined via western blotting and immunoelectron microscopy, respectively. Levels amino acid neurotransmitter release from rat hippocampal synaptosomes and PC12 cells were measured using high performance liquid chromatograph (HPLC) at 6 hours after exposure, with or without synapsin I silencing via shRNA transfection. In the rat experiments, there was a decrease in spatial memory performance after microwave exposure. The expression of p-Syn I (ser-553) was decreased at 3 days post-exposure and elevated at later time points. Vesicular GABA transporter (VGAT) was significantly elevated after exposure. The GABA release from synaptosomes was attenuated and p-Syn I (ser-553) and VGAT were both enriched in small clear synaptic vesicles, which abnormally assembled in the presynaptic terminal after exposure. In the PC12 cell experiments, the expression of p-Syn I (ser-553) and GABA release were both attenuated at 6 hours after exposure. Both microwave exposure and p-Syn I silencing reduced GABA release and maximal reduction was found for the combination of the two, indicating a synergetic effect. p-Syn I (ser-553) was found to play a key role in the impaired GABA release and cognitive dysfunction that was induced by microwave exposure.

Retro-Nasal Aroma Release Is Correlated with Variations in the In-Mouth Air Cavity Volume after Empty Deglutition

PubMed Central

Mishellany-Dutour, Anne; Woda, Alain; Labouré, Hélène; Bourdiol, Pierre; Lachaze, Pauline; Guichard, Elisabeth; Feron, Gilles

2012-01-01

We hypothesized that interindividual differences in motor activities during chewing and/or swallowing were determining factors for the transfer of volatile aroma from the in-mouth air cavity (IMAC) toward the olfactory mucosa. In our first experiment, we looked for changes in IMAC volume after saliva deglutition in 12 healthy subjects. The mean IMAC volume was measured after empty deglutition using an acoustic pharyngometer device. Based on the time course of the IMAC volume after swallowing, we discerned two groups of subjects. The first group displayed a small, constant IMAC volume (2.26 mL ±0.62) that corresponded to a high tongue position. The second group displayed a progressive increase in IMAC (from 6.82 mL ±2.37 to 22.82 mL ±3.04) that corresponded to a progressive lowering of the tongue to its resting position. In our second experiment, we investigated the relationship between IMAC volume changes after deglutition and the level of aroma release at the nostril. For this purpose, the release of menthone was measured at the nostril level in 25 subjects who consumed similar amounts of a mint tablet. The subjects were separated into two groups corresponding to two levels of menthone release: high (H) and low (L). The mean volume of IMAC was measured during and after empty deglutition. Group H displayed a small, constant amplitude of IMAC volume change after deglutition, while Group L displayed a progressive increase in IMAC. It is likely that Group H continuously released the aroma through the veloglossal isthmus as the mint was consumed, while Group L trapped the aroma in the oral cavity and then released it into the nasal cavity upon swallowing. These results show that the in vivo aroma release profile in humans depends closely on the different motor patterns at work during empty deglutition. PMID:22815986

Colloid characterization and in situ release in shallow groundwater under different hydrogeology conditions.

PubMed

Zhou, Jingjing; Liu, Dan; Zhang, Wenjing; Chen, Xuequn; Huan, Ying; Yu, Xipeng

2017-06-01

Changes to groundwater hydrodynamics and chemistry can lead to colloid release that can have a major impact on the groundwater environment. To analyze the effects of colloid release caused by artificial groundwater recharge, field and laboratory tests on colloid characterization and colloid release were conducted. The field tests were carried out at an artificial recharge test site in Shandong Province. In the field investigation, one recharge water sample and five groundwater samples were collected and filtered through three levels of ultrafiltration membranes, with pore sizes of 0.45 μm, 100 kDa, and 50 kDa. The field results indicated that the colloid mass concentrations in groundwater retained between membranes with pore sizes of 100 kDa-0.45 μm and 50 kDa-100 kDa were 19 and 62 mg/L, respectively. In recharge water, the colloid mass concentrations retained by 100-kDa-0.45-μm and 50-kDa-100-kDa membranes were 3 and 99 mg/L, respectively. Colloids detected on the ultrafiltration membranes were mainly inorganic between 100 kDa and 0.45 μm, and mainly organic between 50 and 100 kDa. Based on the field colloid investigation results, the organic colloid was chosen in the laboratory experiments to reveal its release behavior under different conditions. Porous media diameter, flux, ionic strength (IS), and ion valence were changed to determine their influences on organic colloid concentration outflow from undisturbed porous media. The experiment's results indicate that decreasing the diameter, and increasing the flux, ionic strength, and the number of divalent cations, can promote organic colloid release. The organic colloid release rate in the early stage was high and is thus likely to affect the quality of groundwater. The results provide a useful scientific basis for minimizing changes to hydrodynamic and hydrochemical conditions during artificial recharge, thus safeguarding groundwater quality.

Hyperandrogenism induces a proinflammatory TNFα response to glucose ingestion in a receptor-dependent fashion.

PubMed

González, Frank; Sia, Chang Ling; Bearson, Dawn M; Blair, Hilary E

2014-05-01

Hyperandrogenism and inflammation are related in polycystic ovary syndrome (PCOS). Hyperandrogenemia can induce inflammation in reproductive-age women, but the mechanism for this phenomenon is unclear. We examined the in vivo and in vitro effects of hyperandrogenism on mononuclear cell (MNC)-derived androgen receptor (AR) status and TNFα release. This study combined a randomized, controlled, double-blind protocol with laboratory-based cell culture experiments. This work was performed in an academic medical center. Lean, healthy, reproductive-age women were treated with 130 mg of dehydroepiandrosterone (DHEA) or placebo (n = 8 subjects each) for 5 days and also provided untreated fasting blood samples (n = 12 subjects) for cell culture experiments. AR mRNA content and TNFα release were measured before and after DHEA administration in the fasting state and 2 hours after glucose ingestion. TNFα release in the fasting state was also measured in cultured MNCs exposed to androgens with or without flutamide preincubation. At baseline, subjects receiving DHEA or placebo exhibited no significant difference in androgens and TNFα release from MNCs before and after glucose ingestion. Compared with placebo, DHEA administration raised levels of T, androstenedione, and DHEA sulfate, and increased MNC-derived AR mRNA content and TNFα release in the fasting state and in response to glucose ingestion. Compared with MNC exposure to baseline concentrations of DHEA (175 ng/dL) or T (50 ng/dL), the absolute change in TNFα release increased after exposure to T concentrations of 125 and 250 ng/dL and a DHEA concentration of 1750 ng/dL. Preincubation with flutamide reduced the TNFα response by ≥ 60% across all T concentrations. Androgen excess in vivo and in vitro comparable to what is present in PCOS increases TNFα release from MNCs of lean healthy reproductive-age women in a receptor-dependent fashion. Hyperandrogenemia activates and sensitizes MNCs to glucose in this population.

Relationship between nitric oxide- and calcium-dependent signal transduction pathways in growth hormone release from dispersed goldfish pituitary cells.

PubMed

Chang, John P; Sawisky, Grant R; Davis, Philip J; Pemberton, Joshua G; Rieger, Aja M; Barreda, Daniel R

2014-09-15

Nitric oxide (NO) and Ca(2+) are two of the many intracellular signal transduction pathways mediating the control of growth hormone (GH) secretion from somatotropes by neuroendocrine factors. We have previously shown that the NO donor sodium nitroprusside (SNP) elicits Ca(2+) signals in identified goldfish somatotropes. In this study, we examined the relationships between NO- and Ca(2+)-dependent signal transduction mechanisms in GH secretion from primary cultures of dispersed goldfish pituitary cells. Morphologically identified goldfish somatotropes stained positively for an NO-sensitive dye indicating they may be a source of NO production. In 2h static incubation experiments, GH release responses to the NO donor S-nitroso-N-acetyl-d,l-penicillamine (SNAP) were attenuated by CoCl2, nifedipine, verapamil, TMB-8, BHQ, and KN62. In column perifusion experiments, the ability of SNP to induce GH release was impaired in the presence of TMB-8, BHQ, caffeine, and thapsigargin, but not ryanodine. Caffeine-elicited GH secretion was not affected by the NO scavenger PTIO. These results suggest that NO-stimulated GH release is dependent on extracellular Ca(2+) availability and voltage-sensitive Ca(2+) channels, as well as intracellular Ca(2+) store(s) that possess BHQ- and/or thapsigargin-inhibited sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPases, as well as TMB-8- and/or caffeine-sensitive, but not ryanodine-sensitive, Ca(2+)-release channels. Calmodulin kinase-II also likely participates in NO-elicited GH secretion but caffeine-induced GH release is not upstream of NO production. These findings provide insights into how NO actions many integrate with Ca(2+)-dependent signalling mechanisms in goldfish somatotropes and how such interactions may participate in the GH-releasing actions of regulators that utilize both NO- and Ca(2+)-dependent transduction pathways. Copyright © 2014 Elsevier Inc. All rights reserved.

Physiological response of some economically important freshwater salmonids to catch-and-release fishing

USGS Publications Warehouse

Wedemeyer, G.A.; Wydoski, R.S.

2008-01-01

Catch-and-release fishing regulations are widely used by fishery resource managers to maintain both the quantity and quality of sport fish populations. We evaluated blood chemistry disturbances in wild brook trout Salvelinus fontinalis, brown trout Salmo trutta, cutthroat trout Oncorhynchus clarkii, and Arctic grayling Thymallus arcticus that had been hooked and played for 1-5 min in waters of the intermountain western United States. A hatchery stock of brown trout was included for comparison. To assess time needed for recovery, additional test groups were played for 5 min and then released into net-pens, where they were held for up to 72 h. The osmoregulatory and metabolic disturbances associated with catch-and-release fishing under the conditions we tested were minimal and judged to be well within normal physiological tolerance limits. In fish that were held for recovery, the blood chemistry alterations that did occur appeared to be related to stress from confinement in the net-pens. Our results confirm the results of previous studies, showing that prerelease air exposure and handling cause more physiological stress than does either hooking per se or playing time. Fishery managers must be aware of the differences in the perceptions, attitudes, and values of different societal groups, some of which feel that catch-and-release fishing should be banned because it is cruel to the animals. On the basis of brain anatomy, it seems highly unlikely that fish experience pain in the same manner as humans experience it, because fish lack a neocortex, the brain structure that enables the sensation of pain in higher vertebrates. However, independent of the neurobiological argument, our results indicate that under conditions similar to those tested, fish subjected to catch and release are neither suffering nor particularly stressed. Improved education programs about the relatively benign physiological effects of catch-and-release fishing as a fishery management practice would be beneficial to anglers and the nonfishing public alike.

Exploring the additivity of binaural and monaural masking release

PubMed Central

Hall, Joseph W.; Buss, Emily; Grose, John H.

2011-01-01

Experiment 1 examined comodulation masking release (CMR) for a 700-Hz tonal signal under conditions of NoSo (noise and signal interaurally in phase) and NoSπ (noise in phase, signal out of phase) stimulation. The baseline stimulus for CMR was either a single 24-Hz wide narrowband noise centered on the signal frequency [on-signal band (OSB)] or the OSB plus, a set of flanking noise bands having random envelopes. Masking noise was either gated or continuous. The CMR, defined with respect to either the OSB or the random noise baseline, was smaller for NoSπ than NoSo stimulation, particularly when the masker was continuous. Experiment 2 examined whether the same pattern of results would be obtained for a 2000-Hz signal frequency; the number of flanking bands was also manipulated (two versus eight). Results again showed smaller CMR for NoSπ than NoSo stimulation for both continuous and gated masking noise. The CMR was larger with eight than with two flanking bands, and this difference was greater for NoSo than NoSπ. The results of this study are compatible with serial mechanisms of binaural and monaural masking release, but they indicate that the combined masking release (binaural masking-level difference and CMR) falls short of being additive. PMID:21476663

Role of histamine in the inhibitory effects of phycocyanin in experimental models of allergic inflammatory response.

PubMed Central

Remirez, D; Ledón, N; González, R

2002-01-01

It has recently been reported that phycocyanin, a biliprotein found in the blue-green microalgae Spirulina, exerts anti-inflammatory effects in some animal models of inflammation. Taking into account these findings, we decided to elucidate whether phycocyanin might exert also inhibitory effects in the induced allergic inflammatory response and on histamine release from isolated rat mast cells. In in vivo experiments, phycocyanin (100, 200 and 300mg/kg post-orally (p.o.)) was administered 1 h before the challenge with 1 microg of ovalbumin (OA) in the ear of mice previously sensitized with OA. One hour later, myeloperoxidase activity and ear edema were assessed. Phycocyanin significantly reduced both parameters. In separate experiments, phycocyanin (100 and 200 mg/kg p.o.) also reduced the blue spot area induced by intradermal injections of histamine, and the histamine releaser compound 48/80 in rat skin. In concordance with the former results, phycocyanin also significantly reduced histamine release induced by compound 48/80 from isolated peritoneal rat mast cells. The inhibitory effects of phycocyanin were dose dependent. Taken together, our results suggest that inhibition of allergic inflammatory response by phycocyanin is mediated, at least in part, by inhibition of histamine release from mast cells. PMID:12061428

Air exposure and sample storage time influence on hydrogen release from tungsten

NASA Astrophysics Data System (ADS)

Moshkunov, K. A.; Schmid, K.; Mayer, M.; Kurnaev, V. A.; Gasparyan, Yu. M.

2010-09-01

In investigations of hydrogen retention in first wall components the influence of the conditions of the implanted target storage prior to analysis and the storage time is often neglected. Therefore we have performed a dedicated set of experiments. The release of hydrogen from samples exposed to ambient air after irradiation was compared to samples kept in vacuum. For air exposed samples significant amounts of HDO and D 2O are detected during TDS. Additional experiments have shown that heavy water is formed by recombination of releasing D and H atoms with O on the W surface. This water formation can alter hydrogen retention results significantly, in particular - for low retention cases. In addition to the influence of ambient air exposure also the influence of storage time in vacuum was investigated. After implantation at 300 K the samples were stored in vacuum for up to 1 week during which the retained amount decreased significantly. The subsequently measured TDS spectra showed that D was lost from both the high and low energy peaks during storage at ambient temperature of ˜300 K. An attempt to simulate this release from both peaks during room temperature storage by TMAP 7 calculations showed that this effect cannot be explained by conventional diffusion/trapping models.