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Sample records for al concentration profiles

  1. Effect of Doping Profile and Concentration on the Near-Infrared Optical Properties of AlGaN/GaN and AlInN/GaN Heterostructures

    NASA Astrophysics Data System (ADS)

    Cervantes, Mayra; Edmunds, Colin; Li, Donghui; Tang, Liang; Shao, Jiayi; Gardner, Geoff; Manfra, Michael; Malis, Oana

    2012-02-01

    Intersubband (ISB) devices utilizing III-nitrides have recently attracted attention for near- and far- infrared optoelectronic applications. In order to achieve efficient ISB transitions, large doping densities are typically required (>1E18 cm-3). The large impurity density has significant effects on the band structure and material quality, effects that are reflected in important device parameters such as transition energies and linewidths. To determine the optimal doping concentration and profile for III-N intersubband devices, we carried out a systematic study of optical and structural properties of strained AlGaN/GaN and lattice-matched AlInN/GaN heterostructures grown by MBE on quasi-bulk GaN substrates. The lattice-matched AlInN/GaN system is targeted because it allows growth of thick strain-free materials. However, it also presents some considerable growth challenges due to the vastly different optimal growth conditions for Al and In containing nitrides. The transition energy and line profile were determined by direct and photoinduced absorption measurements, while the material quality was assessed using TEM and high resolution x-ray diffraction. The FWHM of the ISB transition at 1.9 μm was found to vary up to 60% with the position of delta doping in the quantum well.

  2. Electrochemical capacitance-voltage profiling of the free-carrier concentration in HEMT heterostructures based on InGaAs/AlGaAs/GaAs compounds

    SciTech Connect

    Brunkov, P. N. Gutkin, A. A.; Rudinsky, M. E.; Ronghin, O. I.; Sitnikova, A. A.; Shakhmin, A. A.; Ber, B. Ya.; Kazantsev, D. Yu.; Egorov, A. Yu.; Zemlyakov, V. E.; Konnikov, S. G.

    2011-06-15

    The depth distribution of free carriers over the HEMT structures with quantum-well layers is studied by electrochemical capacitance-voltage profiling. It is shown that the actual distribution of the concentration of free carriers and their energy spectrum in the HEMT structure channel can be obtained by numerical simulation of the results of profiling based on the self-consistent solution of one-dimensional Schroedinger and Poisson equations.

  3. Concentration profiles for diffusion and nonlinear transport on fractals

    NASA Astrophysics Data System (ADS)

    Giona, M.; Adrover, A.; Schwalm, W.; Schwalm, M.

    1996-03-01

    A Green function renormalization gives transport properties on fractal lattices (finitely or infinitely ramified) to arbitrary numerical precision. We continue an analysis of finite-difference transport modelsfootnote M. Giona et al., Fractals in the Natural and Applied Sciences, ed. M. Novak (North-Holland, Amsterdam, 1994) pp. 153-163; M. Giona et al., Chem. E. Sci. (to appear). focusing on spatial concentration profiles, (2) nonlinear transport, (3) global properties from renormalization of the generating function Z(E) = int d φ exp[-φ^t (H -E I )φ/2] (Adjacency matrix H defines the lattice structure.) by methods not based on decimation. In (1) the Fourier transform of spatial concentration profile is computed as a dynamic structure factor. A perturbation expansion is developed in (2), and (3) presents formalism alternative to that of Tramblay and Southern(Tremblay, B. Southern, J. Phys. Lett. (Paris) 44), 843 (1984)..

  4. Modeling the CAPTEX vertical tracer concentration profiles

    SciTech Connect

    Draxler, R.R.; Stunder, B.J.B.

    1988-05-01

    Perfluorocarbon tracer concentration profiles measured by aircraft 600--900 km downwind of the release locations during CAPTEX are discussed and compared with some model results. In general, the concentrations decreased with height in the upper half of the boundary layer where the aircraft measurements were made. The results of a model sensitivity study suggested that the shape of the profile was primarily due to winds increasing with height and relative position of the sampling with respect to the upwind and downwind edge of the plume. Further modeling studies showed that relatively simple vertical mixing parameterizations could account for the complex vertical plume structure when the model had sufficient vertical resolution. In general, the model performed better with slower winds and corresponding longer transport times.

  5. Modeling the CAPTEX Vertical Tracer Concentration Profiles.

    NASA Astrophysics Data System (ADS)

    Draxler, Roland R.; Stunder, Barbara J. B.

    1988-05-01

    Perfluorocarbon tracer concentration profiles measured by aircraft 600-900 km downwind of the release locations during CAPTEX are discussed and compared with some model results. In general, the concentrations decreased with height in the upper half of the boundary layer where the aircraft measurements were made. The results of a model sensitivity study suggested that the shape of the profile was primarily due to winds increasing with height and relative position of the sampling with respect to the upwind and downwind edge of the plume. Further modeling studies showed that relatively simple vertical mixing parameterizations could account for the complex vertical plume structure when the model had sufficient vertical resolution. In general, the model performed better with slower winds and corresponding longer transport times.

  6. Concentration profiles in drying cylindrical filaments

    NASA Astrophysics Data System (ADS)

    Czaputa, Klaus; Brenn, Günter; Meile, Walter

    2008-12-01

    We analyze theoretically the drying of cylindrical filaments. For modelling the mass transfer on the gas side of the liquid-gas interface of the shrinking circular cylindrical filament, we apply the model of Abramzon and Sirignano, which was originally developed for spherical geometry. As a consequence of mass transfer at constant Sherwood number, we obtain a d2-law for the shrinkage of the cylinder as in the case of the spherical geometry, which expresses that the cross-sectional area of the cylinder shrinks at a constant rate with time. For this situation, the diffusion equation for the liquid phase mixture components becomes separable upon transformation into similarity coordinates and is solved analytically to obtain the concentration profiles inside the filament as functions of time. The dependency of the profiles on the radial coordinate is determined by a series of Kummer’s functions. Applying this result, we study the evolution of the concentration profiles in the liquid phase with time as dependent on a parameter given as the ratio of rate of shrinkage of the cross-sectional area of the cylinder to liquid-phase diffusion coefficient, which was identified as relevant for the shape of the concentration profiles formed in the liquid during the drying process. As an example, we present computed results for the constant evaporation rate regime in the dry-spinning process of a polyvinyl-alcohol (PVA)-water system. Comparison of our analytical results with full numerical solutions of the diffusion equation from the literature, achieved with concentration-dependent diffusion coefficient, reveals very good agreement.

  7. Space charges and defect concentration profiles at complex oxide interfaces

    NASA Astrophysics Data System (ADS)

    Gunkel, Felix; Waser, Rainer; Ramadan, Amr H. H.; De Souza, Roger A.; Hoffmann-Eifert, Susanne; Dittmann, Regina

    2016-06-01

    We discuss electronic and ionic defect concentration profiles at the conducting interface between the two wide-band-gap insulators LaAlO3 and SrTiO3 (STO). The profiles are deduced from a thermodynamic model considering a local space charge layer (SCL) originating from charge transfer to the interface region, thus combining electronic and ionic reconstruction mechanisms. We show that the electrical potential confining the two-dimensional electron gas (2DEG) at the interface modifies the equilibrium defect concentrations in the SCL. For the n -conducting interface, positively charged oxygen vacancies are depleted within the SCL, while negatively charged strontium vacancies accumulate. Charge compensation within the SCL is achieved by a mixed ionic-electronic interface reconstruction, while the competition between 2DEG and localized ionic defects is controlled by ambient p O2 . The concentration of strontium vacancies increases drastically in oxidizing conditions and exhibits a steep depth profile towards the interface. Accounting for the low cation diffusivity in STO, we also discuss kinetic limitations of cation defect formation and the effect of a partial equilibration of the cation sublattice. We discuss the resulting implications for low temperature transport.

  8. Compton Profile Study of Intermetallic Ti{sub 3}Al

    SciTech Connect

    Vyas, V.; Sharma, G.; Mishra, M. C.; Sharma, B. K.; Joshi, K. B.

    2011-10-20

    The Compton scattering measurement on intermetallic alloy Ti{sub 3}Al is reported in this work. The measurement is made using 59.54 keV gamma-rays from Am{sup 241} source. Theoretical calculation of Compton profile is also performed employing CRYSTAL code within the framework of density functional theory to compare with the measurement. The theoretical profile of the alloy is also synthesized following the superposition model taking the published Compton profiles of elemental solids from the APW method. The experimental study of charge transfer in the alloys has also been done by performing the experimental Compton profile measurements on Ti and Al following the superposition model and charge transfer from Al to Ti is clearly seen on the alloy formation.

  9. EVALUATING CONCENTRATION PROFILES DURING UNSTEADY MIXING

    SciTech Connect

    Bamberger, Judith A.; Greenwood, Margaret S.; Lawler, Bruce D.; Sundaram, S. K.; Baer, Ellen BK; Hatchell, Brian K.; Hopkins, Derek F.; Kirihara, Leslie J.; Pekour, Mikhail S.; Sande, Susan; Yu, Xiao-Ying; Zuljevic, Nino

    2010-01-01

    Pulse jet mixing tests to suspend noncohesive solids in Newtonian liquid were conducted at three geometric scales. To understand the solids suspension process an ultrasonic concentration probe was used to measure the concentration of solids in the cloud during a pulse at various elevations and radial positions. The data are being analyzed to provide a model for predicting concentration as a function of elevation. This paper presents a simple single frequency ultrasonic measurement application that demonstrates the ability of ultrasonic sensors to measure slurry concentration based on signal attenuation. Sensor calibration data show that ultrasonic signal attenuation is proportional to the applied frequency and to the slurry volume fraction. Real-time measurements of ultrasonic signal attenuation were used to track the process of slurry mixing using single sensors and sensor arrays. Comparison of means of the ultrasonic measurements with means obtained from discrete extractive measurements show that the distributions overlap and cannot be statistically distinguished. The real-time ultrasonic sensor can be used as a primary measurement method or to reduce reliance upon extractive methods to measure slurry density.

  10. Al-26 depth profile in Apollo 15 drill core

    NASA Technical Reports Server (NTRS)

    Nishiizumi, K.; Arnold, J. R.; Klein, J.; Middleton, R.

    1984-01-01

    Accelerator mass spectrometry is used in a study of galactic cosmic ray production profiles based on cosmic ray-produced Al-26 in the Apollo 15 long core. The results, which are in general agreement with earlier nondestructive counting data, are of significantly higher precision, yet systematically lower. The half-attenuation length for Al-26 production is presently calculated to be 122 g/sq cm, after normalizing the data to average chemical composition.

  11. Profiling the local carrier concentration across a semiconductor quantum dot

    SciTech Connect

    Walrath, J. C.; Lin, Yen-Hsiang; Huang, S.; Goldman, R. S.

    2015-05-11

    We profile the local carrier concentration, n, across epitaxial InAs/GaAs quantum dots (QDs) consisting of 3D islands on top of a 2D alloy layer. We use scanning thermoelectric microscopy to measure a profile of the temperature gradient-induced voltage, which is converted to a profile of the local Seebeck coefficient, S. The S profile is then converted to a conduction band-edge profile and compared with Poisson-Schrodinger band-edge simulations. Our combined computational-experimental approach suggests a reduced carrier concentration in the QD center in comparison to that of the 2D alloy layer. The relative roles of free carrier trapping and/or dopant expulsion are discussed.

  12. Concentration Profiles in Screened Wells Under Static and Pumped Conditions

    SciTech Connect

    McDonald, John P.; Smith, Ronald M.

    2009-05-18

    Purge and pump sampling results from screened wells can be affected by the processes of concentration averaging and contaminant redistribution by wellbore flow. The effects due to concentration averaging were assessed in a screened well at the Hanford Site by investigating the vertical profile of a technetium-99 plume in the aquifer. Nitrate is a co-contaminant with technetium-99 and the dominant anion in the aquifer water, which enabled measurements of specific conductance to be used as an analog for technetium-99. Time-series measurements were collected during purging from three specific conductance probes installed in the well at 1.2 m, 3.1 m, and 4.9 m below the water table in a 7.7 m deep screened well. The vertical contaminant profile in the aquifer was calculated using a wellbore flow and mixing model. The highest concentrations occurred primarily in the upper part of the screened interval, and the purge and pump sample results were 41% to 58% of the calculated peak concentration in the aquifer due to concentration averaging. Plume stratification became more pronounced as pumping continued. Extended pumping may have reversed the effect of contaminant redistribution by wellbore flow. It was also found that the vertical profile of contamination in the wellbore under static (i.e., non-pumping conditions) was not representative of the profile in the aquifer. Thus, passive or micro-purge sampling techniques, which essentially sample the wellbore water, will not necessarily yield results representative of the aquifer.

  13. On the GFP-based analysis of dynamic concentration profiles.

    PubMed

    Berezhkovskii, Alexander M; Shvartsman, Stanislav Y

    2014-02-01

    Studies with GFP-tagged proteins can be used to investigate the dynamics of concentration profiles of regulatory proteins in cells and tissues. Analysis of these experiments must account for the finite rate with which the GFP-tagged proteins mature to the fluorescent state. Toward this end, we present an analytical framework that provides an explicit connection between the apparent kinetics of concentration gradients and the rates of GFP maturation. PMID:24507618

  14. Measurement of stratospheric HOCl - Concentration profiles, including diurnal variation

    NASA Technical Reports Server (NTRS)

    Chance, K. V.; Johnson, D. G.; Traub, W. A.

    1989-01-01

    Determinations have been made of concentration profiles of HOCl in the earth's stratosphere, including the diurnal variation. Measurements of the rotational Q2 branch at 99.5/cm and of five RR(J3) transitions between 143 and 159/cm were made using far-infrared thermal emission spectroscopy. The spectra were obtained during a balloon flight of the FIRS 2 far-infrared Fourier-transform spectrometer and telescope from Palestine, Texas on May 12-13, 1988. From these measurements, altitude profiles of HOCl from 23 to 42 km are obtained. Daytime and nighttime average profiles of HOCl, as well as measurements on a 30-min time scale through the sunset transition at a single (35 km) altitude are presented. The measured profiles are lower than the current predictions from several modeling groups by a factor of approximately 0.6.

  15. Modification of flux profiles using a faceted concentrator

    SciTech Connect

    Lewandowski, A.; Scholl, K.; Bingham, C.

    1993-01-01

    The use of a faceted solar concentrator allows for some flexibility in aiming strategy and in the intensity of the resulting flux profile at the target. This can be an advantage when considering applications that do not necessarily require maximum concentration, particularly emerging, new applications in solar processed advanced materials. This paper will describe both an analysis of predicted flux profiles for several different aiming strategies using the SOLFUR computer code and experiments to characterize the actual flux profiles realized with a selected aiming strategy. The SOLFUR code models each of the furnace components explicitly. Aim points for each facet can be specified. Thus many strategies for adjusting aim points can be easily explored. One strategy calls for creating as uniform a flux over as large an area as possible. We explored this strategy analytically and experimentally. The experimental data consist of flux maps generated by a video imaging system calibrated against absolute flux measurements taken with circular foil calorimeters. Results from the analytical study and a comparison with the experimental data indicate that uniform profiles can be produced over fairly large areas.

  16. Concentric nano rings observed on Al-Cu-Fe microspheres

    NASA Astrophysics Data System (ADS)

    Li, Chunfei; Wang, Limin; Hampikian, Helen; Bair, Matthew; Baker, Andrew; Hua, Mingjian; Wang, Qiongshu; Li, Dingqiang

    2016-05-01

    It is well known that when particle size is reduced, surface effect becomes important. As a result, micro/nanoparticles tend to have well defined geometric shapes to reduce total surface energy, as opposed to the irregular shapes observed in most bulk materials. The surface of such micro/nanostructures are smooth. Any deviation from a smooth surface implies an increased surface energy which is not energetically favorable. Here, we report an observation of spherical particles in an alloy of Al65Cu20Fe15 nominal composition prepared by arc melting. Such spherical particles stand out from those reported so far due to the decoration of concentric nanorings on the surface. Three models for the formation of these concentric ring patterns are suggested. The most prominent ones assume that the rings are frozen features of liquid motion which could open the door to investigate the kinetics of liquid motion on the micro/nanometer scale.

  17. [Gene expression profile of spinal ventral horn in ALS].

    PubMed

    Yamamoto, Masahiko; Tanaka, Fumiaki; Sobue, Gen

    2007-10-01

    The causative pathomechanism of sporadic amyotrophic lateral sclerosis (ALS) is not clearly understood. Using microarray technology combined with laser-captured microdissection, gene expression profiles of degenerating spinal motor neurons as well as spinal ventral horn from autopsied patients with sporadic ALS were examined. Spinal motor neurons showed a distinct gene expression profile from the whole spinal ventral horn. Three percent of genes examined were significantly downregulated, and 1% were upregulated in motor neurons. In contrast with motor neurons, the total spinal ventral horn homogenates demonstrated 0.7% and 0.2% significant upregulation and downregulation of gene expression, respectively. Downregulated genes in motor neurons included those associated with cytoskeleton/axonal transport, transcription and cell surface antigens/receptors, such as dynactin 1 (DCTN1) and early growth response 3 (EGR3). In particular, DCTN1 was markedly downregulated in most residual motor neurons prior to the accumulation of pNF-H and ubiquitylated protein. Promoters for cell death pathway, death receptor 5 (DR5), cyclins C (CCNC) and A1 (CCNA), and caspases were upregulated, whereas cell death inhibitors, acetyl-CoA transporter (ACATN) and NF-kappaB (NFKB) were also upregulated. In terms of spinal ventral horn, the expression of genes related to cell surface antigens/receptors, transcription and cell adhesion/ECM were increased. The gene expression resulting in neurodegenerative and neuroprotective changes were both present in spinal motor neurons and ventral horn. Moreover, Inflammation-related genes, such as belonging to the cytokine family were not, however, significantly upregulated in either motor neurons or ventral horn. The sequence of motor neuron-specific gene expression changes from early DCTN1 downregulation to late CCNC upregulation in sporadic ALS can provide direct information on the genes leading to neurodegeneration and neuronal death, and are helpful

  18. Composition, concentration and charge profiles of water-water interfaces

    NASA Astrophysics Data System (ADS)

    Tromp, R. Hans; Vis, M.; Erné, B. H.; Blokhuis, E. M.

    2014-11-01

    The properties of interfaces are discussed between coexisting phases in phase separated aqueous solutions of polymers. Such interfaces are found in food, where protein-rich and polysaccharide-rich phases coexist. Three aspects of such interfaces are highlighted: the interfacial profiles in terms of polymer composition and polymer concentration, the curvature dependence of the interfacial tension, and the interfacial potential, arising when one of the separated polymers is charged. In all three cases a theoretical approach and methods for experimental verification are presented.

  19. Vertical particle concentration profiles around urban office buildings

    NASA Astrophysics Data System (ADS)

    Quang, T. N.; He, C.; Morawska, L.; Knibbs, L. D.; Falk, M.

    2012-06-01

    Despite its role in determining both indoor and outdoor human exposure to anthropogenic particles, there is limited information describing vertical profiles of particle concentrations in urban environments, especially for ultrafine particles. Furthermore, the results of the few studies performed have been inconsistent. As such, this study aimed to assess the influence of vehicle emissions and nucleation formation on particle characteristics (particle number size distribution - PNSD and PM2.5 concentration) at different heights around three urban office buildings located next to busy roads in Brisbane, Australia, and place these results in the broader context of the existing literature. Two sets of instruments were used to simultaneously measure PNSD, particle number (PN) and PM2.5 concentrations, respectively, for up to three weeks at each building. The results showed that both PNSD and PM2.5 concentration around building envelopes were influenced by vehicle emissions and new particle formation, and that they exhibited variability across the three different office buildings. During nucleation events, PN concentration in size range of <30 nm and total PN concentration increased (7-65% and 5-46%, respectively), while PM2.5 concentration decreased (36-52%) with height. This study has shown an under acknowledged role for nucleation in producing particles that can affect large numbers of people, due to the high density and occupancy of urban office buildings and the fact that the vast majority of people's time is spent indoors. These findings highlight important new information related to the previously overlooked role of particle formation in the urban atmosphere and its potential effects on selection of air intake locations and appropriate filter types when designing or upgrading mechanical ventilation systems in urban office buildings. The results also serve to better define particle behaviour and variability around building envelopes, which has implications for

  20. Scaling Behavior and Segment Concentration Profile of Densely Grafted Polymer Brushes Swollen in Vapor.

    PubMed

    Sun, Liang; Akgun, Bulent; Hu, Renfeng; Browning, James F; Wu, David T; Foster, Mark D

    2016-06-01

    The scaling of the thickness, hs, of a densely grafted polymer brush of chain length N and grafting density σ swollen in vapor agrees quantitatively with the scaling reported by Kuhl et al. for densely grafted brushes swollen in liquid. Deep in the brush, next to the substrate, the shape of the segment concentration profile is the same whether the brush is swollen by liquid or by vapor. Differences in the segment concentration profile are manifested primarily in the swollen brush interface with the surrounding fluid. The interface of the polymer brush swollen in vapor is much more abrupt than that of the same brush swollen in liquid. This has implications for the compressibility of the swollen brush surface and for fluctuations at that surface. PMID:27172089

  1. Relation of morphology of electrodeposited zinc to ion concentration profile

    NASA Technical Reports Server (NTRS)

    May, C. E.; Kautz, H. E.; Sabo, B. B.

    1977-01-01

    The morphology of electrodeposited zinc was studied with special attention to the ion concentration profile. The initial concentrations were 9M hydroxide ion and 1.21M zincate. Current densities were 6.4 to 64 mA/sq cm. Experiments were run with a horizontal cathode which was observed in situ using a microscope. The morphology of the zinc deposit was found to be a function of time as well as current density; roughly, the log of the transition time from mossy to large crystalline type deposit is inversely proportional to current density. Probe electrodes indicated that the electrolyte in the cathode chamber was mixed by self inducted convection. However, relatively large concentration gradients of the involved species existed across the boundary layer of the cathode. Analysis of the data suggests that the morphology converts from mossy to large crystalline when the hydroxide activity on the cathode surface exceeds about 12 M. Other experiments show that the pulse discharge technique had no effect on the morphology in the system where the bulk concentration of the electrolyte was kept homogeneous via self induced convection.

  2. Exhaled methane concentration profiles during exercise on an ergometer

    PubMed Central

    Szabó, A; Ruzsanyi, V; Unterkofler, K; Mohácsi, Á; Tuboly, E; Boros, M; Szabó, G; Hinterhuber, H; Amann, A

    2016-01-01

    Exhaled methane concentration measurements are extensively used in medical investigation of certain gastrointestinal conditions. However, the dynamics of endogenous methane release is largely unknown. Breath methane profiles during ergometer tests were measured by means of a photoacoustic spectroscopy based sensor. Five methane-producing volunteers (with exhaled methane level being at least 1 ppm higher than room air) were measured. The experimental protocol consisted of 5 min rest—15 min pedalling (at a workload of 75 W)—5 min rest. In addition, hemodynamic and respiratory parameters were determined and compared to the estimated alveolar methane concentration. The alveolar breath methane level decreased considerably, by a factor of 3–4 within 1.5 min, while the estimated ventilation-perfusion ratio increased by a factor of 2–3. Mean pre-exercise and exercise methane concentrations were 11.4 ppm (SD:7.3) and 2.8 ppm (SD:1.9), respectively. The changes can be described by the high sensitivity of exhaled methane to ventilationperfusion ratio and are in line with the Farhi equation. PMID:25749807

  3. Blood cadmium concentration and lipid profile in Korean adults

    SciTech Connect

    Kim, Kisok

    2012-01-15

    Although animal experiments have shown that cadmium exposure induces alterations in lipid profiles, no epidemiological study of this relationship has been performed. The objective of this study was to evaluate the association between blood cadmium concentration and blood lipid levels in Korean adults. A cross-sectional study comprising participants (n=3903) aged 20 years or older from the 2005, 2008, and 2009 Korea National Health and Nutrition Examination Surveys was conducted. Demographic characteristics and dietary intake were obtained from the participants by questionnaire, and cadmium and lipid levels were determined by analysis of blood samples. After adjusting for demographic and dietary factors, blood concentration of cadmium was positively associated with the risk of low high-density lipoprotein cholesterol (HDL-C) in a dose-dependent manner (p for trend <0.001). In addition, the odds ratios (ORs) of a high triglyceride to HDL-C ratio was significantly increased in the high blood cadmium groups [OR=1.36; 95% confidence interval (CI), 1.03-1.79 for fourth quintile and OR=1.41; 95% CI, 1.07-1.86 for fifth quintile] compared with the lowest quintile group. However, high blood cadmium was not associated with a risk of high total cholesterol, high low-density lipoprotein cholesterol, or high triglycerides. These data suggest that an increased cadmium body burden increases the risk of dyslipidemia, mainly due to the increased risk of low HDL-C and the high ratio of triglycerides to HDL-C.

  4. Concentration profiles of actin-binding molecules in lamellipodia

    NASA Astrophysics Data System (ADS)

    Falcke, Martin

    2016-04-01

    Motile cells form lamellipodia in the direction of motion, which are flat membrane protrusions containing an actin filament network. The network flows rearward relative to the leading edge of the lamellipodium due to actin polymerization at the front. Thus, actin binding molecules are subject to transport towards the rear of the cell in the bound state and diffuse freely in the unbound state. We analyze this reaction-diffusion-advection process with respect to the concentration profiles of these species and provide an analytic approximation for them. Network flow may cause a depletion zone of actin binding molecules close to the leading edge. The existence of such zone depends on the free molecule concentration in the cell body, on the ratio of the diffusion length to the distance bound molecules travel rearward with the flow before dissociating, and the ratio of the diffusion length to the width of the region with network flow and actin binding. Our calculations suggest the existence of depletion zones for the F-actin cross-linkers filamin and α-actinin in fish keratocytes (and other cell types), which is in line with the small elastic moduli of the F-actin network close to the leading edge found in measurements of the force motile cells are able to exert.

  5. A model for HAZ hardness profiles in Al-Li-X alloys: Application to the Al-Li-Cu Alloy 2095

    SciTech Connect

    Rading, G.O.; Shamsuzzoha, M.; Berry, J.T.

    1998-10-01

    In a previous paper details were presented of a theoretical model describing the evolution of the hardness profiles in the heat-affected zones (HAZ) of Al-Li-X weldments. The intent of the model was to qualitatively predict the general shape of such a profile, which indicates points of double inflection. In the present paper, experimental results are presented to validate the model. Panels of Al-Li-Cu Alloy 2095 in the peak aged (T8) condition were welded by the gas tungsten arc (GTA) process using AA 2319 filler metal. Conventional transmission electron microscopy (TEM) studies were conducted on specimens taken from specific points across the HAZ to estimate the relative ratios of T{sub 1} (Al{sub 2}CuLi) and {delta}{prime} (Al{sub 3}Li) precipitates, as well as incoherent grain boundary phases. Electron probe microanalysis (EPMA) was used to determine the variation of concentrations of elements across the HAZ, while the hardness profile was determined using Vickers microhardness measurements. The hardness profile and the associated pattern of phases present agree well with the information predicted qualitatively by the previously described model.

  6. Dating a tropical ice core by time-frequency analysis of ion concentration depth profiles

    NASA Astrophysics Data System (ADS)

    Gay, M.; De Angelis, M.; Lacoume, J.-L.

    2014-09-01

    Ice core dating is a key parameter for the interpretation of the ice archives. However, the relationship between ice depth and ice age generally cannot be easily established and requires the combination of numerous investigations and/or modelling efforts. This paper presents a new approach to ice core dating based on time-frequency analysis of chemical profiles at a site where seasonal patterns may be significantly distorted by sporadic events of regional importance, specifically at the summit area of Nevado Illimani (6350 m a.s.l.), located in the eastern Bolivian Andes (16°37' S, 67°46' W). We used ion concentration depth profiles collected along a 100 m deep ice core. The results of Fourier time-frequency and wavelet transforms were first compared. Both methods were applied to a nitrate concentration depth profile. The resulting chronologies were checked by comparison with the multi-proxy year-by-year dating published by de Angelis et al. (2003) and with volcanic tie points. With this first experiment, we demonstrated the efficiency of Fourier time-frequency analysis when tracking the nitrate natural variability. In addition, we were able to show spectrum aliasing due to under-sampling below 70 m. In this article, we propose a method of de-aliasing which significantly improves the core dating in comparison with annual layer manual counting. Fourier time-frequency analysis was applied to concentration depth profiles of seven other ions, providing information on the suitability of each of them for the dating of tropical Andean ice cores.

  7. A model for heat-affected zone hardness profiles in Al-Li-X alloys

    SciTech Connect

    Rading, G.O.; Berry, J.T.

    1998-09-01

    A model based on reaction kinetics and elemental diffusion is proposed to account for the presence of double inflection in the hardness profiles of the heat-affected zone (HAZ) in weldments of Al-Li-X alloys tested without postweld heat treatment (PWHT). Such profiles are particularly evident when (1) the base metal is in the peak-aged (T8 or T6) temper condition prior to welding; (2) the welding process is a high-heat input process, i.e., gas tungsten arc (GTA), gas metal arc (GMA) or plasma arc (PA) welding; and (3) a filler alloy deficient in lithium (i.e., AA 2319) is used. In the first part of this paper, the theoretical mechanisms are presented. It is proposed that the double inflection appears due to complete or partial reversion of the semi-coherent, plate-like precipitates (i.e., {theta}{prime}, T{sub 1} or S{prime}); coarsening of the plate-like precipitates at constant volume fraction; precipitation of {delta}{prime} as a result of natural aging; and diffusion of lithium from the HAZ into the weld pool due to the concentration gradient between the weld pool and the base metal. In the second part (to be published in next month`s Welding Journal), experimental validation of the model is provided using weldments of the Al-Li-Cu Alloy 2095.

  8. Thermodynamic analysis of the concentration profiles of epitaxial layers of nonideal solid solutions

    SciTech Connect

    Kazakov, A.I.; Kishmar, I.N.; Mokritskii, V.A.; Yakubovskii, M.V.

    1988-03-01

    Based on thermodynamic analysis employing the quasiregular approach a mathematical model of the process of equilibrium crystallization of nonideal three-component solid solutions of compounds of the type A/sup III/B/sup V/ from a restricted volume of a solution in a melt was constructed. This model enables calculation of the distribution of the components over the thickness of the epitaxial layer for low rates of cooling of the solution in a melt. The computer calculations of the concentration profiles of the epitaxial layers of Ga/sub 1-x/Al/sub x/ agreed well with the experimental data for thicknesses of the epitaxial layers up to 20 ..mu..m. For high rates of cooling the mass transfer in the volume of the solution in a melt must be taken into account.

  9. Profiling the local carrier concentration and dopant distribution across a semiconductor quantum dot

    NASA Astrophysics Data System (ADS)

    Walrath, J. C.; Chang, A. S.; Lin, Y. H.; Huang, S.; Goldman, R. S.

    We profile the local carrier concentration, n, across epitaxial InAs/GaAs quantum dots (QDs) consisting of 3D islands on top of a 2D alloy layer. We use scanning thermoelectric microscopy to profile the temperature gradient-induced voltage, which is converted to a profile of the local Seebeck coefficient, S. The S profile is then converted to a conduction band-edge profile and compared with Poisson-Schrodinger band-edge simulations. Our combined computational-experimental approach suggests a reduced carrier concentration in the QD center in comparison to that of the 2D alloy layer. We further use 3D atom probe tomography, which enables 3D imaging with a few Angstrom resolution, to profile the distribution of Si dopants. We discuss the correlation between the Si dopant distribution and the observed carrier concentration profile.

  10. Nondestructive depth profile of the chemical state of ultrathin Al2O3/Si interface

    NASA Astrophysics Data System (ADS)

    Lee, Jong Cheol; Oh, S.-J.

    2004-05-01

    We investigated a depth profile of the chemical states of an Al2O3/Si interface using nondestructive photon energy-dependent high-resolution x-ray photoelectron spectroscopy (HRXPS). The Si 2p binding energy, attributed to the oxide interfacial layer (OIL), was found to shift from 102.1 eV to 102.9 eV as the OIL region closer to Al2O3 layer was sampled, while the Al 2p binding energy remains the same. This fact strongly suggests that the chemical state of the interfacial layer is not Al silicate as previously believed. We instead propose from the HRXPS of Al 2p and Si 2p depth-profile studies that the chemical states of the Al2O3/Si interface mainly consist of SiO2 and Si2O3.

  11. Measuring the depth profiles of strain/composition in AlGaN-graded layer by high-resolution x-ray diffraction

    SciTech Connect

    Kuchuk, A. V.; Stanchu, H. V.; Kladko, V. P.; Belyaev, A. E.; Li, Chen; Ware, M. E.; Mazur, Yu. I.; Salamo, G. J.

    2014-12-14

    Here, we demonstrate X-ray fitting through kinematical simulations of the intensity profiles of symmetric reflections for epitaxial compositionally graded layers of AlGaN grown by molecular beam epitaxy pseudomorphically on [0001]-oriented GaN substrates. These detailed simulations depict obvious differences between changes in thickness, maximum concentration, and concentration profile of the graded layers. Through comparison of these simulations with as-grown samples, we can reliably determine these parameters, most important of which are the profiles of the concentration and strain which determine much of the electrical properties of the film. In addition to learning about these parameters for the characterization of thin film properties, these fitting techniques create opportunities to calibrate growth rates and control composition profiles of AlGaN layers with a single growth rather than multiple growths as has been done traditionally.

  12. Pathway-Based Concentration Response Profiles from Toxicogenomics Data

    EPA Science Inventory

    Microarray analysis of gene expression of in vitro systems could be a powerful tool for assessing chemical hazard. Differentially expressed genes specific to cells, chemicals, and concentrations can be organized into molecular pathways that inform mode of action. An important par...

  13. Simplified 2DEG carrier concentration model for composite barrier AlGaN/GaN HEMT

    SciTech Connect

    Das, Palash Biswas, Dhrubes

    2014-04-24

    The self consistent solution of Schrodinger and Poisson equations is used along with the total charge depletion model and applied with a novel approach of composite AlGaN barrier based HEMT heterostructure. The solution leaded to a completely new analytical model for Fermi energy level vs. 2DEG carrier concentration. This was eventually used to demonstrate a new analytical model for the temperature dependent 2DEG carrier concentration in AlGaN/GaN HEMT.

  14. Reduction in the Number of Mg Acceptors with Al Concentration in Al x Ga1- x N

    NASA Astrophysics Data System (ADS)

    Sunay, U. R.; Zvanut, M. E.; Allerman, A. A.

    2015-11-01

    High hole concentrations in Al x Ga1- x N become increasingly difficult to obtain as the Al mole fraction increases. The problem is believed to be related to compensation, extended defects, and the band gap of the alloy. Whereas electrical measurements are commonly used to measure hole density, in this work we used electron paramagnetic resonance (EPR) spectroscopy to investigate a defect related to the neutral Mg acceptor. The amount and symmetry of neutral Mg in MOCVD-grown Al x Ga1- x N with x = 0 to 0.28 was monitored for films with different dislocation densities and surface conditions. EPR measurements indicated that the amount of neutral Mg decreased by 60% in 900°C-annealed Al x Ga1- x N films for x = 0.18 and 0.28 as compared with x = 0.00 and 0.08. A decrease in the angular dependence of the EPR signal accompanied the increased x, suggesting a change in the local environment of the Mg. Neither dislocation density nor annealing conditions contribute to the reduced amount of neutral Mg in samples with the higher Al concentration. Rather, compensation is the simplest explanation of the observations, because a donor could both reduce the number of neutral acceptors and cause the variation in the angular dependence.

  15. Effect of AlCl3 concentration on nanoparticle removal by coagulation.

    PubMed

    Zhang, Lizhu; Mao, Jingchun; Zhao, Qing; He, Shaobo; Ma, Jun

    2015-12-01

    In recent years, engineered nanoparticles, as a new group of contaminants emerging in natural water, have been given more attention. In order to understand the behavior of nanoparticles in the conventional water treatment process, three kinds of nanoparticle suspensions, namely multi-walled carbon nanotube-humic acid (MWCNT-HA), multi-walled carbon nanotube-N,N-dimethylformamide (MWCNT-DMF) and nanoTiO2-humic acid (TiO2-HA) were employed to investigate their coagulation removal efficiencies with varying aluminum chloride (AlCl3) concentrations. Results showed that nanoparticle removal rate curves had a reverse "U" shape with increasing concentration of aluminum ion (Al(3+)). More than 90% of nanoparticles could be effectively removed by an appropriate Al(3+) concentration. At higher Al(3+) concentration, nanoparticles would be restabilized. The hydrodynamic particle size of nanoparticles was found to be the crucial factor influencing the effective concentration range (ECR) of Al(3+) for nanoparticle removal. The ECR of Al(3+) followed the order MWCNT-DMF>MWCNT-HA>TiO2-HA, which is the reverse of the nanoparticle size trend. At a given concentration, smaller nanoparticles carry more surface charges, and thus consume more coagulants for neutralization. Therefore, over-saturation occurred at relatively higher Al(3+) concentration and a wider ECR was obtained. The ECR became broader with increasing pH because of the smaller hydrodynamic particle size of nanoparticles at higher pH values. A high ionic strength of NaCl can also widen the ECR due to its strong potential to compress the electric double layer. It was concluded that it is important to adjust the dose of Al(3+) in the ECR for nanoparticle removal in water treatment. PMID:26702973

  16. GAS PHASE EXPOSURE HISTORY DERIVED FROM MATERIAL PHASE CONCENTRATION PROFILES USING SOLID PHASE MICRO-EXTRACTION

    EPA Science Inventory

    EPA Identifier: F8P31059
    Title: Gas Phase Exposure History Derived from Material Phase Concentration Profiles Using Solid Phase Micro-Extraction
    Fellow (Principal Investigator): Jonathan Lewis McKinney
    Institution: University of Missouri - ...

  17. Effect of asymmetric concentration profile on thermal conductivity in Ge/SiGe superlattices

    NASA Astrophysics Data System (ADS)

    Hahn, Konstanze R.; Cecchi, Stefano; Colombo, Luciano

    2016-05-01

    The effect of the chemical composition in Si/Ge-based superlattices on their thermal conductivity has been investigated using molecular dynamics simulations. Simulation cells of Ge/SiGe superlattices have been generated with different concentration profiles such that the Si concentration follows a step-like, a tooth-saw, a Gaussian, and a gamma-type function in direction of the heat flux. The step-like and tooth-saw profiles mimic ideally sharp interfaces, whereas Gaussian and gamma-type profiles are smooth functions imitating atomic diffusion at the interface as obtained experimentally. Symmetry effects have been investigated comparing the symmetric profiles of the step-like and the Gaussian function to the asymmetric profiles of the tooth-saw and the gamma-type function. At longer sample length and similar degree of interdiffusion, the thermal conductivity is found to be lower in asymmetric profiles. Furthermore, it is found that with smooth concentration profiles where atomic diffusion at the interface takes place the thermal conductivity is higher compared to systems with atomically sharp concentration profiles.

  18. Point defect concentrations and solid solution hardening in NiAl with Fe additions

    SciTech Connect

    Pike, L.M.; Chang, Y.A.; Liu, C.T.

    1997-08-01

    The solid solution hardening behavior exhibited when Fe is added to NiAl is investigated. This is an interesting problem to consider since the ternary Fe additions may choose to occupy either the Ni or the Al sublattice, affecting the hardness at differing rates. Moreover, the addition of Fe may affect the concentrations of other point defects such as vacancies and Ni anti-sites. As a result, unusual effects ranging from rapid hardening to solid solution softening are observed. Alloys with varying amounts of Fe were prepared in Ni-rich (40 at. % Al) and stoichiometric (50 at. % Al) compositions. Vacancy concentrations were measured using lattice parameter and density measurements. The site occupancy of Fe was determined using ALCHEMI. Using these two techniques the site occupancies of all species could be uniquely determined. Significant differences in the defect concentrations as well as the hardening behavior were encountered between the Ni-rich and stoichiometric regimes.

  19. Profiling the PM2.5 mass concentration vertical distribution in the boundary layer

    NASA Astrophysics Data System (ADS)

    Tao, Z.; Wang, Z.; Yang, S.; Shan, H.; Ma, X.; Zhang, H.; Zhao, S.; Liu, D.; Xie, C.; Wang, Y.

    2015-12-01

    Fine particle (PM2.5) affects human life and activities directly; the detection of PM2.5 mass concentration profile is very essential due to its practical and scientific meanings (such as, quantifying of air quality and its variability, and improving air quality forecast and assessment). But so far, it is difficult to detect PM2.5 mass concentration profile. The proposed methodology to study the relationship between aerosol extinction coefficient and PM2.5 mass concentration is described, which indicates that the PM2.5 mass concentration profile could be retrieved by combining a charge-coupled device (CCD) side-scatter lidar and a PM2.5 sampling detector. When the relative humidity is less than 70 %, PM2.5 mass concentration is proportional to aerosol extinction coefficient, and then the specific coefficient can be calculated. Using this specific coefficient, aerosol extinction profile is converted to PM2.5 mass concentration profile. Three cases of clean night (on 21 September 2014), pollutant night (on 17 March 2014), and heavy pollutant night (on 13 February 2015) are studied. The characteristic of PM2.5 mass concentration profile in near-ground during these three nights' cases in the western suburb of Hefei city was discussed. The PM2.5 air pollutant concentration is comparatively large in close surface varying with time and altitude. The experiment results show that the CCD side-scatter lidar combined with a PM2.5 detector is an effective and new method to explore pollutant mass concentration profile in near-ground.

  20. Profiling the PM2.5 mass concentration vertical distribution in the boundary layer

    NASA Astrophysics Data System (ADS)

    Tao, Zongming; Wang, Zhenzhu; Yang, Shijun; Shan, Huihui; Ma, Xiaomin; Zhang, Hui; Zhao, Sugui; Liu, Dong; Xie, Chenbo; Wang, Yingjian

    2016-04-01

    Fine particles (PM2.5) affect human life and activities directly; the detection of PM2.5 mass concentration profile is very essential due to its practical and scientific significance (such as the quantification of air quality and its variability as well as the assessment of improving air quality forecast). But so far, it has been difficult to detect PM2.5 mass concentration profile. The proposed methodology to study the relationship between aerosol extinction coefficient and PM2.5 mass concentration is described, which indicates that the PM2.5 mass concentration profile could be retrieved by combining a charge-coupled device (CCD) side-scatter lidar with a PM2.5 sampling detector. When the relative humidity is less than 70 %, PM2.5, mass concentration is proportional to the aerosol extinction coefficient, and then the specific coefficient can be calculated. Through this specific coefficient, aerosol extinction profile is converted to PM2.5 mass concentration profile. Three cases of clean night (on 21 September 2014), pollutant night (on 17 March 2014), and heavy pollutant night (on 13 February 2015) are studied. The characteristics of PM2.5 mass concentration profile at the near-ground level during the cases of these 3 nights in the western suburb of Hefei city were discussed. The PM2.5 air pollutant concentration is comparatively large close to the surface and varies with time and altitude. The experiment results show that the CCD side-scatter lidar combined with a PM2.5 detector is an effective and new method to explore pollutant mass concentration profile at the near-ground level.

  1. Dissolution wear: Decomposition of tool material, and concentration profile into chip

    NASA Astrophysics Data System (ADS)

    Wong, Tim Kong-Ping

    The predictive capability of Kramer's theory of dissolution wear has raised questions as to whether dissolution or diffusion is the dominant mechanism underlying tool wear. The diffusion mechanism finds support in experimentation and modeling of mass transfer (e.g., the Molinari-Nouari model of the experimental findings of Subramanian et al.), and fits more naturally in the setting of the irreversibilities of turning processes. Kramer's dissolution mechanism, by contrast, is based on equilibrium thermodynamics. Our present aim is to re-phrase the dissolution hypothesis of tool wear as a boundary condition for species transfer within the chip's bulk via diffusion. In this setting, dissolution is defined as the combined events of tool decomposition at the interface and the subsequent mass transfer of decomposed elements into the chip region. A set of equations is constructed wherein the tool is treated as a mechanically rigid, but chemically active, thermal conductor; the chip is treated as a rigid-perfectly plastic, thermally conducting material; and the behavior of the frictional-contact interface between tool and chip is described by a weak coupling of thermal and mass transfer. Chemical equilibrium is invoked for the distribution of tool species at the tool-chip interface. The Frank-Turnbull mechanism of molecular reaction (between interstitial impurities and vacancies to form substitutional impurities) is used as a hypothesis to explain the concentration profile of tool constituents into the chip as found by Subramanian et al. in 1993. The present interpretation of the Frank-Turnbull mechanism is illustrated by finite-element simulations. Physical parameters have either been estimated or curve-fitted to observed data, and the level of inexactness inherent in the curve-fit process limits the present work to a demonstration of only the sufficiency of the model. The assumptions made, their implications, parameters varied, and quantities calculated are summarized in

  2. From the shape of the vertical profile of in vivo fluorescence to Chlorophyll-a concentration

    NASA Astrophysics Data System (ADS)

    Mignot, A.; Claustre, H.; D'Ortenzio, F.; Xing, X.; Poteau, A.; Ras, J.

    2011-04-01

    In vivo fluorescence of Chlorophyll-a (Chl-a) is a potentially useful property to study the vertical distribution of phytoplankton biomass. However the technique is presently not fully exploited as it should be, essentially because of the difficulties in converting the fluorescence signal into an accurate Chl-a concentration. These difficulties arise noticeably from natural variations in the Chl-a fluorescence relationship, which is under the control of community composition as well as of their nutrient and light status. As a consequence although vertical profiles of fluorescence are likely the most recorded biological property in the open ocean, the corresponding large databases are underexploited. Here with the aim to convert a fluorescence profile into a Chl-a concentration profile, we test the hypothesis that the Chl-a concentration can be gathered from the sole knowledge of the shape of the fluorescence profile. We analyze a large dataset from 18 oceanographic cruises conducted in case-1 waters from the highly stratified hyperoligotrophic waters (surface Chl-a = 0.02 mg m-3) of the South Pacific Gyre to the eutrophic waters of the Benguela upwelling (surface Chl-a = 32 mg m-3) and including the very deep mixed waters in the North Atlantic (Mixed Layer Depth = 690 m). This dataset encompasses more than 700 vertical profiles of Chl-a fluorescence as well as accurate estimations of Chl-a by High Performance Liquid Chromatography (HPLC). Two typical fluorescence profiles are identified, the uniform profile, characterized by a homogeneous layer roughly corresponding to the mixed layer, and the non-uniform profile, characterized by the presence of a Deep Chlorophyll Maximum. Using appropriate mathematical parameterizations, a fluorescence profile is subsequently represented by 3 or 5 shape parameters for uniform or non-uniform profiles, respectively. For both situations, an empirical model is developed to predict the "true" Chl-a concentration from these shape

  3. From the shape of the vertical profile of in vivo fluorescence to Chlorophyll-a concentration

    NASA Astrophysics Data System (ADS)

    Mignot, A.; Claustre, H.; D'Ortenzio, F.; Xing, X.; Poteau, A.; Ras, J.

    2011-08-01

    In vivo fluorescence of Chlorophyll-a (Chl-a) is a potentially useful property to study the vertical distribution of phytoplankton biomass. However the technique is presently not fully exploited as it should be, essentially because of the difficulties in converting the fluorescence signal into an accurate Chl-a concentration. These difficulties arise noticeably from natural variations in the Chl-a fluorescence relationship, which is under the control of community composition as well as of their nutrient and light status. As a consequence, although vertical profiles of fluorescence are likely the most recorded biological property in the open ocean, the corresponding large databases are underexploited. Here with the aim to convert a fluorescence profile into a Chl-a concentration profile, we test the hypothesis that the Chl-a concentration can be gathered from the sole knowledge of the shape of the fluorescence profile. We analyze a large dataset from 18 oceanographic cruises conducted in case-1 waters from the highly stratified hyperoligotrophic waters (surface Chl-a = 0.02 mg m-3) of the South Pacific Gyre to the eutrophic waters of the Benguela upwelling (surface Chl-a = 32 mg m-3) and including the very deep mixed waters in the North Atlantic (Mixed Layer Depth = 690 m). This dataset encompasses more than 700 vertical profiles of Chl-a fluorescence as well as accurate estimations of Chl-a by High Performance Liquid Chromatography (HPLC). Two typical fluorescence profiles are identified, the uniform profile, characterized by a homogeneous layer roughly corresponding to the mixed layer, and the non-uniform profile, characterized by the presence of a Deep Chlorophyll Maximum. Using appropriate mathematical parameterizations, a fluorescence profile is subsequently represented by 3 or 5 shape parameters for uniform or non-uniform profiles, respectively. For both situations, an empirical model is developed to predict the "true" Chl-a concentration from these shape

  4. Modeling of breath methane concentration profiles during exercise on an ergometer*

    PubMed Central

    Szabó, Anna; Unterkofler, Karl; Mochalski, Pawel; Jandacka, Martin; Ruzsanyi, Vera; Szabó, Gábor; Mohácsi, Árpád; Teschl, Susanne; Teschl, Gerald; King, Julian

    2016-01-01

    We develop a simple three compartment model based on mass balance equations which quantitatively describes the dynamics of breath methane concentration profiles during exercise on an ergometer. With the help of this model it is possible to estimate the endogenous production rate of methane in the large intestine by measuring breath gas concentrations of methane. PMID:26828421

  5. Flux-Profile Relationship for Dust Concentration in the Stratified Atmospheric Surface Layer

    NASA Astrophysics Data System (ADS)

    Freire, L. S.; Chamecki, M.; Gillies, J. A.

    2016-08-01

    Flux-profile relationships are usually obtained under the assumption that the mean field of interest is in equilibrium with the associated surface fluxes. In this study, the existence of an equilibrium state for dust concentration in the atmospheric surface layer above sources and sinks is evaluated using large-eddy simulation. Results show that for steady-state turbulence and negligible horizontal advection, an equilibrium mean vertical profile of dust concentration is reached after one boundary-layer eddy turnover time. This is true for cases over a source or sink, under different atmospheric stabilities, and for particles with negligible or significant settling velocity. A new model relating the net surface flux to the vertical concentration profile that accounts for both atmospheric stability and particle settling velocity is proposed. The model compares well with the simulation results for all particle sizes and atmospheric stability conditions evaluated, and it can be used to estimate the concentration profile based on the surface flux, and also to estimate the surface flux by fitting the vertical concentration profile. The resulting equation can be considered as an extension of Monin-Obukhov similarity theory to the concentration of settling particles, such as mineral dust, sea-salt, pollen and other suspended aerosols.

  6. Flux-Profile Relationship for Dust Concentration in the Stratified Atmospheric Surface Layer

    NASA Astrophysics Data System (ADS)

    Freire, L. S.; Chamecki, M.; Gillies, J. A.

    2016-03-01

    Flux-profile relationships are usually obtained under the assumption that the mean field of interest is in equilibrium with the associated surface fluxes. In this study, the existence of an equilibrium state for dust concentration in the atmospheric surface layer above sources and sinks is evaluated using large-eddy simulation. Results show that for steady-state turbulence and negligible horizontal advection, an equilibrium mean vertical profile of dust concentration is reached after one boundary-layer eddy turnover time. This is true for cases over a source or sink, under different atmospheric stabilities, and for particles with negligible or significant settling velocity. A new model relating the net surface flux to the vertical concentration profile that accounts for both atmospheric stability and particle settling velocity is proposed. The model compares well with the simulation results for all particle sizes and atmospheric stability conditions evaluated, and it can be used to estimate the concentration profile based on the surface flux, and also to estimate the surface flux by fitting the vertical concentration profile. The resulting equation can be considered as an extension of Monin-Obukhov similarity theory to the concentration of settling particles, such as mineral dust, sea-salt, pollen and other suspended aerosols.

  7. Radial Combustion Dynamics in Fe2O3/Al Thermite: Variability of the Flame Propagation Profiles

    NASA Astrophysics Data System (ADS)

    Durães, L.; Plaksin, I.; Antunes, J.; Campos, J.; Portugal, A.

    2009-12-01

    In this work, the radial combustion in thin circular samples of stoichiometric and over aluminized Fe2O3/Al mixtures is studied. Two confinement materials are tested: stainless steel and PVC. The combustion front profiles are registered by digital video-crono-photography. The radial geometry allows an easy detection of sample heterogeneities, via the circularity distortions of the combustion front profiles. The influence of the Al content in the mixtures and the type of confinement on the combustion propagation dynamics is analyzed. Additionally, an asymmetry parameter of the combustion front profiles is defined and statistically treated via ANOVA. Although the type of confinement contributes more than the mixture composition to the variability of the asymmetry parameter, they both have a weak influence. The main source of variability is the intrinsic variations of the samples, which are due to their heterogeneous character.

  8. Gas-phase exposure history derived from material-phase concentration profiles

    NASA Astrophysics Data System (ADS)

    Morrison, G. C.; Little, J. C.; Xu, Y.; Rao, M.; Enke, D.

    Non-reactive gas-phase pollutants such as benzene diffuse into indoor furnishings and leave behind a unique material-phase concentration profile that serves as a record of the past gas-phase indoor concentrations. The inverse problem to be solved is the diffusion equation in a slab such as vinyl flooring. Using knowledge of the present material-phase concentration profile in the slab, we seek to determine the historical material-phase concentration at the surface exposed to indoor air, and hence the historical gas-phase concentration, which can be used directly to determine exposure. The problem as posed has a unique solution that may be solved using a variety of approaches. We use a trained artificial neural network (ANN) to derive solutions for hypothetical exposure scenarios. The ANN results show that it is possible to estimate the intensity and timing of past exposures from the material-phase concentration profile in a building material. The overall method is limited by (1) the resolution of techniques for measuring spatial material-phase concentration profiles, (2) how far back in time we seek to determine exposure and (3) the representational power of the ANN solution. For example, we estimate that this technique can estimate exposure to phenol up to 0.5 y in the past from analyses of vinyl flooring.

  9. Estimation of skin concentrations of topically applied lidocaine at each depth profile.

    PubMed

    Oshizaka, Takeshi; Kikuchi, Keisuke; Kadhum, Wesam R; Todo, Hiroaki; Hatanaka, Tomomi; Wierzba, Konstanty; Sugibayashi, Kenji

    2014-11-20

    Skin concentrations of topically administered compounds need to be considered in order to evaluate their efficacies and toxicities. This study investigated the relationship between the skin permeation and concentrations of compounds, and also predicted the skin concentrations of these compounds using their permeation parameters. Full-thickness skin or stripped skin from pig ears was set on a vertical-type diffusion cell, and lidocaine (LID) solution was applied to the stratum corneum (SC) in order to determine in vitro skin permeability. Permeation parameters were obtained based on Fick's second law of diffusion. LID concentrations at each depth of the SC were measured using tape-stripping. Concentration-depth profiles were obtained from viable epidermis and dermis (VED) by analyzing horizontal sections. The corresponding skin concentration at each depth was calculated based on Fick's law using permeation parameters and then compared with the observed value. The steady state LID concentrations decreased linearly as the site became deeper in SC or VED. The calculated concentration-depth profiles of the SC and VED were almost identical to the observed profiles. The compound concentration at each depth could be easily predicted in the skin using diffusion equations and skin permeation data. Thus, this method was considered to be useful for promoting the efficient preparation of topically applied drugs and cosmetics. PMID:25158219

  10. Measurements of CO2 Concentration and Wind Profiles with A Scanning 1.6μm DIAL

    NASA Astrophysics Data System (ADS)

    Abo, M.; Shibata, Y.; Nagasawa, C.; Nagai, T.; Sakai, T.; Tsukamoto, M.

    2012-12-01

    Horizontal carbon dioxide (CO2) distribution and wind profiles are important information for understanding of the regional sink and source of CO2. The differential absorption lidar (DIAL) and the Doppler lidar with the range resolution is expected to bring several advantages over passive measurements. We have developed a new scanning 1.6μm DIAL and incoherent Doppler lidar system to perform simultaniously measurements of CO2 concentration and wind speed profiles in the atmosphere. The 1.6μm DIAL and Doppler lidar system consists of the Optical Parametric Generator (OPG) transmitter that excited by the LD pumped Nd:YAG laser with high repetition rate (500 Hz). The receiving optics include the near-infrared photomultiplier tube with high quantum efficiency operating at the photon counting mode, a fiber Bragg grating (FBG) filter to detct Doppler shift, and a 25 cm telescope[1][2]. Laser beam is transmitted coaxially and motorized scanning mirror system can scan the laser beam and field of view 0-360deg horizontally and 0-52deg vertically. We report the results of vertical CO2 scanning measurenents and vertical wind profiles. The scanning elevation angles were from 12deg to 24deg with angular step of 4deg and CO2 concentration profiles were obtained up to 1 km altitude with 200 m altitude resolution. We also obtained vertical wind vector profiles by measuring line-of-sight wind profiles at two azimuth angles with a fixed elevation angle 52deg. Vertical wind vector profiles were obtained up to 5 km altitude with 1 km altitude rasolution. This work was financially supported by the System Development Program for Advanced Measurement and Analysis of the Japan Science and Technology Agency. References [1] L. B. Vann, et al., "Narrowband fiber-optic phase-shifted Fabry-Perot Bragg grating filters for atmospheric water vapor lidar measurements", Appl. Opt., 44, pp. 7371-7377 (2005). [2] Y. Shibata, et al., "1.5μm incoherent Doppler lidar using a FBG filter", Proceedings

  11. Effect of boron concentration on recombination at the p-Si–Al{sub 2}O{sub 3} interface

    SciTech Connect

    Black, Lachlan E. Allen, Thomas; Cuevas, Andres; McIntosh, Keith R.

    2014-03-07

    We examine the surface passivation properties of Al{sub 2}O{sub 3} deposited on boron-doped planar 〈100〉 crystalline silicon surfaces as a function of the boron concentration. Both uniformly doped and diffused surfaces are studied, with surface boron concentrations ranging from 9.2 × 10{sup 15} to 5.2 × 10{sup 19} cm{sup −3}. Atmospheric pressure chemical vapor deposition and thermal atomic layer deposition are used to deposit the Al{sub 2}O{sub 3} films. The surface recombination rate of each sample is determined from photoconductance measurements together with the measured dopant profiles via numerical simulation, using the latest physical models. These values are compared with calculations based on the interface properties determined from capacitance–voltage and conductance measurements. It is found that the fundamental surface recombination velocity of electrons, S{sub n0}, which describes the chemical passivation of the interface, is independent of the surface boron concentration N{sub s} for N{sub s} ≤ 3 × 10{sup 19} cm{sup −3}, and in excellent agreement with values calculated from the interface state density D{sub it} and capture coefficients c{sub n} and c{sub p} measured on undiffused boron-doped surfaces. We conclude that the physical properties of the Si–Al{sub 2}O{sub 3} interface are independent of the boron dopant concentration over this range.

  12. Effect of Al Doping Concentration on Microstructure, Photoelectric Properties and Doped Mechanism of Azo Films

    NASA Astrophysics Data System (ADS)

    Xu, Ying; Cai, Yanqing; Hou, Linyan; Ma, Penghua

    2014-05-01

    Al doped ZnO (AZO) thin films were deposited on a glass substrate by atmospheric pressure chemical vapor deposition (APCVD) method. Effect of Al doping concentration on microstructure, photoelectric properties and doped mechanism of AZO thin films were investigated. The analysis results revealed that the structural properties of the films possessed crystalline structure with a preferred (002) orientation. The best crystallization quality and minimum electrical resistivity was obtained at 5 at.% Al doped films and the minimum resistivity was 6.6 × 10-4 Ω ṡ cm. Uniform granular grains were observed on the surface of AZO films, and the average optical transmittance was above 80% in the visible range. The doped mechanism of AZO films was analyzed as follows. With Al doping in ZnO films, AlZn substitute and Ali interstice were produced, which decreased the resistivity of films. While after the limit value and with the continuing increase of Al doping concentration, free electrons were consumed and the resistivity of films increased.

  13. Electrical properties of n-type AlGaN with high Si concentration

    NASA Astrophysics Data System (ADS)

    Takeda, Kunihiro; Iwaya, Motoaki; Takeuchi, Tetsuya; Kamiyama, Satoshi; Akasaki, Isamu

    2016-05-01

    The electrical properties of Si-doped AlGaN layers (AlN molar fractions: 0.03-0.06) with the donor concentrations (N D) from 8.8 × 1017 to 4.5 × 1020 cm-3 were investigated by variable-temperature Hall effect measurement using the van der Pauw method. A minimum resistivity of 3.6 × 10-4 Ω cm was obtained for Si-doped AlGaN with a smooth surface at room temperature. We found that the activation energy of the Si donor is affected by the Coulomb interaction in the AlGaN layer with N D values from 8.8 × 1017 to 2.5 × 1020 cm-3. In several AlGaN layers, the free-electron concentration did not vary with sample temperature, as expected in the case of degeneracy. The localization of GaN in the AlGaN layer was speculated as a cause of degeneracy of samples.

  14. Position-dependent chemotactic response of slowly migrating cells in sigmoidal concentration profiles

    NASA Astrophysics Data System (ADS)

    Renner, A.; Jaeger, M. S.; Lankenau, A.; Duschl, C.

    2013-09-01

    Characterizing the chemotactic motility of slowly migrating cells as a function of time is still challenging. In this paper, we use a microfluidic device for investigating the chemotactic activity of HFF-1 fibroblasts in a sigmoidal concentration profile of epidermal growth factor (EGF). Sigmoidal concentration profiles are very common in biological systems but, in contrast to linear gradients, are much less studied in microfluidic systems. We monitored cell migration for up to 10 hours and found that chemotaxis is strongest where the absolute EGF concentration is below 25 pM ( K D of EGF is 1 nM). Calculating the fraction of receptor occupancy ( FRO) at the front and rear of the cells showed that the chemotactic activity of HFF-1 cells scaled with the difference in FRO between both ends of the cell normalized by the average FRO av of the cell. Interestingly, the mean chemotactic index of the cells was found to be a function of the gradient at the starting position and did not change when cells were entering into other regions of the highly non-linear concentration profile. Our studies demonstrate the usefulness of stable sigmoidal concentration profiles produced in microfluidic channels for a detailed analysis of the chemotactic response of slowly migrating cells.

  15. Sub-microradian Surface Slope Metrology with the ALS Developmental Long Trace Profiler

    SciTech Connect

    Yashchuk, Valeriy V; Barber, Samuel; Domning, Edward E.; Kirschman, Jonathan L.; Morrison, Gregory Y.; Smith, Brian V; Siewert, Frank; Zeschke, Thomas; Geckeler, Ralf; Just, Andreas

    2009-09-11

    A new low budget slope measuring instrument, the Developmental Long Trace Profiler (DLTP), was recently brought to operation at the ALS Optical Metrology Laboratory. The design, instrumental control and data acquisition system, initial alignment and calibration procedures, as well as the developed experimental precautions and procedures are described in detail. The capability of the DLTP to achieve sub-microradian surface slope metrology is verified via cross-comparison measurements with other high performance slope measuring instruments when measuring the same high quality test optics. The directions of future work to develop a surface slope measuring profiler with nano-radian performance are also discussed.

  16. MultiDark simulations: the story of dark matter halo concentrations and density profiles

    NASA Astrophysics Data System (ADS)

    Klypin, Anatoly; Yepes, Gustavo; Gottlöber, Stefan; Prada, Francisco; Heß, Steffen

    2016-04-01

    Predicting structural properties of dark matter haloes is one of the fundamental goals of modern cosmology. We use the suite of MultiDark cosmological simulations to study the evolution of dark matter halo density profiles, concentrations, and velocity anisotropies. We find that in order to understand the structure of dark matter haloes and to make 1-2 per cent accurate predictions for density profiles, one needs to realize that halo concentration is more complex than the ratio of the virial radius to the core radius in the Navarro-Frenk-White (NFW) profile. For massive haloes, the average density profile is far from the NFW shape and the concentration is defined by both the core radius and the shape parameter α in the Einasto approximation. We show that haloes progress through three stages of evolution. They start as rare density peaks and experience fast and nearly radial infall that brings mass closer to the centre, producing a highly concentrated halo. Here, the halo concentration increases with increasing halo mass and the concentration is defined by the α parameter with a nearly constant core radius. Later haloes slide into the plateau regime where the accretion becomes less radial, but frequent mergers still affect even the central region. At this stage, the concentration does not depend on halo mass. Once the rate of accretion and merging slows down, haloes move into the domain of declining concentration-mass relation because new accretion piles up mass close to the virial radius while the core radius is staying constant. Accurate analytical fits are provided.

  17. Influence of particles shape on the vertical profile of blowing snow concentration

    NASA Astrophysics Data System (ADS)

    Vionnet, Vincent; Trouvilliez, Alexandre; Naaim-Bouvet, Florence; Guyomarc'h, Gilbert

    2013-04-01

    In alpine regions, blowing snow events strongly influence the temporal and spatial evolution of the snow cover throughout the winter season. In Antarctica, blowing snow is an essential surface mass balance process and plays a non-negligible role in the annual accumulation. The vertical profile of blowing snow concentration determines the quantity of snow transported in turbulent suspension. A power law is often used to represent this vertical profile. It serves as an analytical solution representing an equilibrium between vertical turbulent diffusion and gravitational settling. In this work, we study how the exponent of the power law depends on the type of transported particles. Vertical profiles of blowing snow concentration have been collected at the experimental site of Col du Lac Blanc (French Alps) in 2011 and 2012 and near the research station of Cap Prud'homme (Antarctica) in 2010 and 2011. We used mechanical gauges (butterfly nets) and optical devices (Snow Particles Counters). Profiles collected during blowing snow events with precipitation have been corrected to account for the contribution of snowfall. Results show that profiles collected during blowing snow without snowfall differ from the corrected profiles collected during snowfall. At a given wind speed, particles transported during snowfall have a lower settling velocity than particles transported without snowfall. This difference confirms earlier observations (Takahashi, 1985) and can be explained by the change of drag coefficient between dendritic and rounded particles. This difference pertains several hours after the end of the snowfall illustrating the fragmentation of snow grains during blowing snow events.

  18. Vertical Tracer Concentration Profiles Measured During the Joint Urban 2003 Dispersion Study

    SciTech Connect

    Flaherty, Julia E.; Lamb, Brian K.; Allwine, K Jerry; Allwine, Eugene J.

    2007-12-01

    An atmospheric tracer dispersion study known as Joint Urban 2003 was conducted in Oklahoma City, Oklahoma during the summer of 2003. As part of this field program, vertical concentration profiles were measured at approximately 1 km from downtown tracer gas release locations. These profiles indicated that the urban landscape was very effective in mixing the plume vertically. The height of the plume centerline (as determined by the maximum concentration over the depth of the measurements) for any specific 30 min period varied over the 65 m measurement range. Most of the variations in tracer concentration observed in the profile time series were related to changes in wind direction as opposed to changes in turbulence. As a simple analysis tool for emergency response, maximum normalized concentration curves were developed with 5-minute averaged measurements. These curves give the maximum concentration (normalized by the release rate) that would be observed as a function of downwind distance in an urban area. The 5-min data resulted in greater concentrations than predicted with a simple Gaussian plume model. However, the curve compared well with results from a computational fluid dynamics simulation. This dispersion dataset is a valuable asset not only for refining air quality models, but also for developing new tools for emergency response personnel in the event of a toxic release.

  19. 1.6μm DIAL System for Measurements of CO2 Concentration Profiles in the Atmosphere

    NASA Astrophysics Data System (ADS)

    Nagasawa, C.; Abo, M.; Shibata, Y.

    2013-12-01

    We have developed a direct detection 1.6 μm differential absorption lidar (DIAL) technique to perform range-resolved measurements of vertical CO2 concentration profiles in the atmosphere. Our 1.6 μm DIAL system has a 60 cm telescope for vertical measurement and a 25 cm scanning telescope for horizontal measurement. This 1.6 μm DIAL system is also available to measure CO2 concentration profiles for daytime by using narrow-band interference filters. The 1.6 μm DIAL measurement was achieved successfully the vertical CO2 profile up to 7 km altitude with an error less than 1.0 % by integration time of 30 minutes and vertical resolution of 300 - 600 m. The CO2 DIAL was also operated with the range-height indicator (RHI) mode, and the 2-D measurement provided inhomogeneity in the boundary layer. The vertical distribution of CO2 concentration from 2 km to 7 km altitude has been observed using two telescopes with different apertures. We hope to get the data of the CO2 concentration from lower altitude to 7 km at the same time. Since the change of signal intensity is larger near the ground, it is also important to the install the photon counter with the faster count rate to expand the dynamic range. The high speed counter and the telescope system make the dynamic range expand more than 10 times and the vertical distribution observation of CO2 concentration from 0.5 km to 7 km altitude is performed. This work was financially supported by the System Development Program for Advanced Measurement and Analysis of the Japan Science and Technology Agency. References Sakaizawa, D., C. Nagasawa, T. Nagai, M. Abo, Y. Shibata, H. Nagai, M. Nakazato, and T. Sakai, Development of a 1.6μm differential absorption lidar with a quasi-phase-matching optical parametric oscillator and photon-counting detector for the vertical CO2 profile, Applied Optics, Vol.48, No.4, pp. 748-757, 2009. Stephens, B. B. et al., Weak Northern and Strong Tropical Land Carbon Uptake from Vertical Profiles of

  20. Determining concentration depth profiles in fluorinated networks by means of electric force microscopy

    SciTech Connect

    Miccio, Luis A.; Schwartz, Gustavo A.

    2011-08-14

    By means of electric force microscopy, composition depth profiles were measured with nanometric resolution for a series of fluorinated networks. By mapping the dielectric permittivity along a line going from the surface to the bulk, we were able to experimentally access to the fluorine concentration profile. Obtained data show composition gradient lengths ranging from 30 nm to 80 nm in the near surface area for samples containing from 0.5 to 5 wt. % F, respectively. In contrast, no gradients of concentration were detected in bulk. This method has several advantages over other techniques because it allows profiling directly on a sectional cut of the sample. By combining the obtained results with x-ray photoelectron spectroscopy measurements, we were also able to quantify F/C ratio as a function of depth with nanoscale resolution.

  1. Sub-microradian Surface Slope Metrology with the ALS Developmental Long Trace Profiler

    SciTech Connect

    Yashchuk, Valeriy V.; Barber, Samuel; Domning, Edward E.; Kirschman, Jonathan L.; Morrison, Gregory Y.; Smith, Brian V.; Siewert, Frank; Zeschke, Thomas; Geckeler, Ralf; Just, Andreas

    2009-06-15

    Development of X-ray optics for 3rd and 4th generation X-ray light sources with a level of surface slope precision of 0.1-0.2 {micro}rad requires the development of adequate fabrication technologies and dedicated metrology instrumentation and methods. Currently, the best performance of surface slope measurement has been achieved with the NOM (Nanometer Optical Component Measuring Machine) slope profiler at BESSY (Germany) [1] and the ESAD (Extended Shear Angle Difference) profiler at the PTB (Germany) [2]. Both instruments are based on electronic autocollimators (AC) precisely calibrated for the specific application [3] with small apertures of 2.5-5 mm in diameter. In the present work, we describe the design, initial alignment and calibration procedures, the instrumental control and data acquisition system, as well as the measurement performance of the Developmental Long Trace Profiler (DLTP) slope measuring instrument recently brought into operation at the Advanced Light Source (ALS) Optical Metrology Laboratory (OML). Similar to the NOM and ESAD, the DLTP is based on a precisely calibrated autocollimator. However, this is a reasonably low budget instrument used at the ALS OML for the development and testing of new measuring techniques and methods. Some of the developed methods have been implemented into the ALS LTP-II (slope measuring long trace profiler [4]) which was recently upgraded and has demonstrated a capability for 0.25 {micro}rad surface metrology [5]. Performance of the DLTP was verified via a number of measurements with high quality reference mirrors. A comparison with the corresponding results obtained with the world's best slope measuring instrument, the BESSY NOM, proves the accuracy of the DLTP measurements on the level of 0.1-0.2 {micro}rad depending on the curvature of a surface under test. The directions of future work to develop a surface slope measuring profiler with nano-radian performance are also discussed.

  2. Changes in mineral concentrations and phosphorus profile during dry-grind process of corn into ethanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For determining variation in mineral composition and phosphorus (P) profile among streams of dry-grind ethanol production, samples of ground corn, intermediate streams, and distillers dried grains with solubles (DDGS) were obtained from 3 commercial plants. Most attributes (dry matter concentration...

  3. School Profiles of At-Risk Student Concentration: Differential Growth in Oral Reading Fluency

    ERIC Educational Resources Information Center

    Logan, Jessica A. R.; Petscher, Yaacov

    2010-01-01

    The present study provides a data-driven approach to identifying groups of schools based on the concentration of at-risk students the school serves. The percentage of English language learners, minority students, and students eligible for free or reduced priced lunch were used as indicators in a latent profile analysis of 569 schools. The goal of…

  4. Associations between Serum Sex Hormone Concentrations and Whole Blood Gene Expression Profiles in the General Population

    PubMed Central

    Homuth, Georg; Steil, Leif; Völker, Uwe; Völzke, Henry; Keevil, Brian G.; Nauck, Matthias; Wallaschofski, Henri

    2015-01-01

    Background Despite observational evidence from epidemiological and clinical studies associating sex hormones with various cardiometabolic risk factors or diseases, pathophysiological explanations are sparse to date. To reveal putative functional insights, we analyzed associations between sex hormone levels and whole blood gene expression profiles. Methods We used data of 991 individuals from the population-based Study of Health in Pomerania (SHIP-TREND) with whole blood gene expression levels determined by array-based transcriptional profiling and serum concentrations of total testosterone (TT), sex hormone-binding globulin (SHBG), free testosterone (free T), dehydroepiandrosterone sulfate (DHEAS), androstenedione (AD), estradiol (E2), and estrone (E1) measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and immunoassay. Associations between sex hormone concentrations and gene expression profiles were analyzed using sex-specific regression models adjusted for age, body mass index, and technical covariables. Results In men, positive correlations were detected between AD and DDIT4 mRNA levels, as well as between SHBG and the mRNA levels of RPIA, RIOK3, GYPB, BPGM, and RAB2B. No additional significant associations were observed. Conclusions Besides the associations between AD and DDIT4 expression and SHBG and the transcript levels of RPIA, RIOK3, GYPB, BPGM, and RAB2B, the present study did not indicate any association between sex hormone concentrations and whole blood gene expression profiles in men and women from the general population. PMID:26001193

  5. Pharmacokinetic Modeling to Simulate the Concentration-Time Profiles After Dermal Application of Rivastigmine Patch.

    PubMed

    Nozaki, Sachiko; Yamaguchi, Masayuki; Lefèvre, Gilbert

    2016-07-01

    Rivastigmine is an inhibitor of acetylcholinesterases and butyrylcholinesterases for symptomatic treatment of Alzheimer disease and is available as oral and transdermal patch formulations. A dermal absorption pharmacokinetic (PK) model was developed to simulate the plasma concentration-time profile of rivastigmine to answer questions relative to the efficacy and safety risks after misuse of the patch (e.g., longer application than 24 h, multiple patches applied at the same time, and so forth). The model comprised 2 compartments which was a combination of mechanistic dermal absorption model and a basic 1-compartment model. The initial values for the model were determined based on the physicochemical characteristics of rivastigmine and PK parameters after intravenous administration. The model was fitted to the clinical PK profiles after single application of rivastigmine patch to obtain model parameters. The final model was validated by confirming that the simulated concentration-time curves and PK parameters (Cmax and area under the drug plasma concentration-time curve) conformed to the observed values and then was used to simulate the PK profiles of rivastigmine. This work demonstrated that the mechanistic dermal PK model fitted the clinical data well and was able to simulate the PK profile after patch misuse. PMID:27212635

  6. High-efficiency AlGaAs-GaAs Cassegrainian concentrator cells

    NASA Technical Reports Server (NTRS)

    Werthen, J. G.; Hamaker, H. C.; Virshup, G. F.; Lewis, C. R.; Ford, C. W.

    1985-01-01

    AlGaAs-GaAs heteroface space concentrator solar cells have been fabricated by metalorganic chemical vapor deposition. AMO efficiencies as high as 21.1% have been observed both for p-n and np structures under concentration (90 to 100X) at 25 C. Both cell structures are characterized by high quantum efficiencies and their performances are close to those predicted by a realistic computer model. In agreement with the computer model, the n-p cell exhibits a higher short-circuit current density.

  7. In vivo confocal Raman microspectroscopy of the skin: noninvasive determination of molecular concentration profiles.

    PubMed

    Caspers, P J; Lucassen, G W; Carter, E A; Bruining, H A; Puppels, G J

    2001-03-01

    Confocal Raman spectroscopy is introduced as a noninvasive in vivo optical method to measure molecular concentration profiles in the skin. It is shown how it can be applied to determine the water concentration in the stratum corneum as a function of distance to the skin surface, with a depth resolution of 5 microm. The resulting in vivo concentration profiles are in qualitative and quantitative agreement with published data, obtained by in vitro X-ray microanalysis of skin samples. Semi-quantitative concentration profiles were determined for the major constituents of natural moisturizing factor (serine, glycine, pyrrolidone-5-carboxylic acid, arginine, ornithine, citrulline, alanine, histidine, urocanic acid) and for the sweat constituents lactate and urea. A detailed description is given of the signal analysis methodology that enables the extraction of this information from the skin Raman spectra. No other noninvasive in vivo method exists that enables an analysis of skin molecular composition as a function of distance to the skin surface with similar detail and spatial resolution. Therefore, it may be expected that in vivo confocal Raman spectroscopy will find many applications in basic and applied dermatologic research. PMID:11231318

  8. Vertical profiles of black carbon concentration and particle number size distribution in the North China Plain

    NASA Astrophysics Data System (ADS)

    Ran, L.; Deng, Z.

    2013-12-01

    The vertical distribution of aerosols is of great importance to our understanding in the impacts of aerosols on radiation balance and climate, as well as air quality and public health. To better understand and estimate the effects of atmospheric components including trace gases and aerosols on atmospheric environment and climate, an intensive field campaign, Vertical Observations of trace Gases and Aerosols in the North China Plain (VOGA-NCP), was carried out from late July to early August 2013 over a rural site in the polluted NCP. During the campaign, vertical profiles of black carbon (BC) concentration and particle number size distribution were measured respectively by a micro-Aethalometer and an optical particle counter attached to a tethered balloon within 1000 m height. Meteorological parameters, including temperature, relative humidity, wind speed and wind direction, were measured simultaneously by a radiosonde also attached to the tethered balloon. Preliminary results showed distinct diurnal variations of the vertical distribution of aerosol total number concentration and BC concentration, following the development of the mixing layer. Generally, there was a well mixing of aerosols within the mixing layer and a sharp decrease above the mixing layer. Particularly, a small peak of BC concentrations was observed around 400-500 m height for several profiles. Further analysis would be needed to explain such phenomenon. It was also found that measured vertical profiles of BC using the filter-based method might be affected by the vertical distribution of relative humidity.

  9. Probing the carrier concentration profiles in phosphorus-implanted germanium using infrared spectroscopic ellipsometry

    SciTech Connect

    D'Costa, Vijay Richard Yeo, Yee-Chia

    2015-02-21

    Spectroscopic ellipsometry with photon energy in the 0.045–0.65 eV range was used to investigate germanium samples implanted with 30 keV phosphorus ions and annealed at 700 °C. The infrared response of implanted layers is dominated by free carrier absorption which is modeled using a Drude oscillator. The carrier concentration profiles were modeled using an error function, and compared with those obtained by electrochemical capacitance-voltage profiling and secondary ion mass spectrometry. In the flat region of the carrier concentration profile, average carrier concentration and mobility of 1.40 × 10{sup 19} cm{sup −3} and 336 cm{sup 2}V{sup −1}s{sup −1}, respectively, were obtained. A phosphorus diffusivity of ∼1.2 × 10{sup −13} cm{sup 2}/s was obtained. The mobility versus carrier concentration relationships obtained for the implanted samples are close to the empirical relationship for bulk Ge.

  10. The effect of aerosol vertical profiles on satellite-estimated surface particle sulfate concentrations

    SciTech Connect

    Liu, Yang; Wang, Zifeng; Wang, Jun; Ferrare, Richard A.; Newsom, Rob K.; Welton, Ellsworth J.

    2011-02-15

    The aerosol vertical distribution is an important factor in determining the relationship between satellite retrieved aerosol optical depth (AOD) and ground-level fine particle pollution concentrations. We evaluate how aerosol profiles measured by ground-based lidar and simulated by models can help improve the association between AOD retrieved by the Multi-angle Imaging Spectroradiometer (MISR) and fine particle sulfate (SO4) concentrations using matched data at two lidar sites. At the Goddard Space Flight Center (GSFC) site, both lidar and model aerosol profiles marginally improve the association between SO4 concentrations and MISR fractional AODs, as the correlation coefficient between cross-validation (CV) and observed SO4 concentrations changes from 0.87 for the no-scaling model to 0.88 for models scaled with aerosol vertical profiles. At the GSFC site, a large amount of urban aerosols resides in the well-mixed boundary layer so the column fractional AODs are already excellent indicators of ground-level particle pollution. In contrast, at the Atmospheric Radiation Measurement Program (ARM) site with relatively low aerosol loadings, scaling substantially improves model performance. The correlation coefficient between CV and observed SO4 concentrations is increased from 0.58 for the no-scaling model to 0.76 in the GEOS-Chem scaling model, and the model bias is reduced from 17% to 9%. In summary, despite the inaccuracy due to the coarse horizontal resolution and the challenges of simulating turbulent mixing in the boundary layer, GEOS-Chem simulated aerosol profiles can still improve methods for estimating surface aerosol (SO4) mass from satellite-based AODs, particularly in rural areas where aerosols in the free troposphere and any long-range transport of aerosols can significantly contribute to the column AOD.

  11. Characterization of Florida red tide aerosol and the temporal profile of aerosol concentration

    PubMed Central

    Cheng, Yung Sung; Zhou, Yue; Pierce, Richard H.; Henry, Mike; Baden, Daniel G.

    2009-01-01

    Red tide aerosols containing aerosolized brevetoxins are produced during the red tide bloom and transported by wind to coastal areas of Florida. This study reports the characterization of Florida red tide aerosols in human volunteer studies, in which an asthma cohort spent 1 h on Siesta Beach (Sarasota, Florida) during aerosolized red tide events and non-exposure periods. Aerosol concentrations, brevetoxin levels, and particle size distribution were measured. Hourly filter samples were taken and analyzed for brevetoxin and NaCl concentrations. In addition, the aerosol mass concentration was monitored in real time. The results indicated that during a non-exposure period in October 2004, no brevetoxin was detected in the water, resulting in non-detectable levels of brevetoxin in the aerosol. In March 2005, the time-averaged concentrations of brevetoxins in water samples were moderate, in the range of 5–10 μg/L, and the corresponding brevetoxin level of Florida red tide aerosol ranged between 21 and 39 ng/m3. The temporal profiles of red tide aerosol concentration in terms of mass, NaCl, and brevetoxin were in good agreement, indicating that NaCl and brevetoxins are components of the red tide aerosol. By continuously monitoring the marine aerosol and wind direction at Siesta Beach, we observed that the marine aerosol concentration varied as the wind direction changed. The temporal profile of the Florida red tide aerosol during a sampling period could be explained generally with the variation of wind direction. PMID:19879288

  12. Using the Rouse Concentration Model to Represent Vertical Flux Profiles of Wind Blown Sand

    NASA Astrophysics Data System (ADS)

    Farrell, Eugene; Sherman, Douglas

    2014-05-01

    From studies of suspended sediments in water or dust in air it is recognized that the Rouse profile represents a theoretically sound, first approximation of characteristic concentration gradients. Rouse (1938) combined the influence of grain size and shear velocity changes into a universal equation for concentration gradients. The Rouse number relates sediment size (in the form of settling velocity, w0) to shear velocity, the von Kármán constant (0.4) and the Schmidt Number, typically assumed to be equal to 1.0 but with much larger values reported. The shape of the Rouse concentration profile is controlled by the Rouse number exponent. We applied the Rouse profile model to 14 vertical flux profiles of wind-blown sand measured during a field experiment in Jericoacoara, Brazil in 2008. These data were supplemented with 96 vertical flux profiles obtained from fourteen wind tunnel and field experiments reported in the literature, for a total of 110 profiles. A fall velocity equation for particles falling in air was derived using a grain size (d) dependency: w0 (in m/s) = 4.248 (in mm) + 0.174 (r2=0.88). The Rouse model performs poorly when the value of the β (a form of the Schmidt number in the Rouse number exponent) is assumed to be unity. The values of β were modeled using a relationship derived from a dependency of β on the w0/u* ratio: β = 3.277(w0/u*) - 0.4133 (r2=0.65). The Rouse profiles calculated using this approach predict very similar vertical distributions to the observed data and predicted 86% and 81% of the observed transport rate in field and wind tunnel experiments respectively. The analyses show that the performance of the Rouse model is not sensitive to changes in the range of variability we can expect to observe in values of fall velocity, shear velocity and the von Kármán constant but is very sensitive to changes in the values of the Schmidt number. The Rouse approach is more physically meaningful than current approaches that use standard

  13. Experimental and numerical results for CO2 concentration and temperature profiles in an occupied room

    NASA Astrophysics Data System (ADS)

    Cotel, Aline; Junghans, Lars; Wang, Xiaoxiang

    2014-11-01

    In recent years, a recognition of the scope of the negative environmental impact of existing buildings has spurred academic and industrial interest in transforming existing building design practices and disciplinary knowledge. For example, buildings alone consume 72% of the electricity produced annually in the United States; this share is expected to rise to 75% by 2025 (EPA, 2009). Significant reductions in overall building energy consumption can be achieved using green building methods such as natural ventilation. An office was instrumented on campus to acquire CO2 concentrations and temperature profiles at multiple locations while a single occupant was present. Using openFOAM, numerical calculations were performed to allow for comparisons of the CO2 concentration and temperature profiles for different ventilation strategies. Ultimately, these results will be the inputs into a real time feedback control system that can adjust actuators for indoor ventilation and utilize green design strategies. Funded by UM Office of Vice President for Research.

  14. DIAL Measurements of Free-Tropospheric Ozone Profiles in Huntsville, AL

    NASA Technical Reports Server (NTRS)

    Kuang, Shi; Burris, John; Newchurch, Michael J.; Johnson, Steve

    2007-01-01

    A tropospheric ozone Differential Absorption Lidar (DIAL) system, developed jointly by NASA and the University of Alabama at Huntsville (UAH), measures free-tropospheric ozone profiles between 4-10 km. Located at 192 meters altitude in the Regional Atmospheric Profiling Laboratory for Discovery (RAPCD) on the UAH campus in Huntsville, AL, USA, this tropospheric ozone lidar operates under both daytime and nighttime conditions. Frequent coincident ozonesonde flights and theoretical calculations provide evidence to indicate the retrieval accuracy ranges from better than 8% at 4km to 40%-60% at 10 kin with 750-m vertical resolution and 30-minute integration. With anticipated improvements to allow retrievals at both higher and lower altitudes, this ozone lidar, along with co-located aerosol and Doppler Wind Lidars, will provide a unique 18 dataset for investigations of PBL and free-tropospheric chemical and dynamic processes.

  15. Characterizing contaminant concentrations with depth by using the USGS well profiler in Oklahoma, 2003-9

    USGS Publications Warehouse

    Smith, S. Jerrod; Becker, Carol J.

    2011-01-01

    In 2007, the USGS well profiler was used to investigate saline water intrusion in a deep public-supply well completed in the Ozark (Roubidoux) aquifer. In northeast Oklahoma, where the Ozark aquifer is known to be susceptible to contamination from mining activities, the well profiler also could be used to investigate sources (depths) of metals contamination and to identify routes of entry of metals to production wells.Water suppliers can consider well rehabilitation as a potential remediation strategy because of the ability to identify changes in contaminant concentrations with depth in individual wells with the USGS well profiler. Well rehabilitation methods, which are relatively inexpensive compared to drilling and completing new wells, involve modifying the construction or operation of a well to enhance the production of water from zones with lesser concentrations of a contaminant or to limit the production of water from zones with greater concentrations of a contaminant. One of the most effective well rehabilitation methods is zonal isolation, in which water from contaminated zones is excluded from production through installation of cement plugs or packers. By using relatively simple and inexpensive well rehabilitation methods, water suppliers may be able to decrease exposure of customers to contaminants and avoid costly installation of additional wells, conveyance infrastructure, and treatment technologies.

  16. Electrotransport of Molybdenum Through an Electrodialysis Membrane. Concentration and Potentiel Profiles in Aqueous Interfacial Layers

    NASA Astrophysics Data System (ADS)

    Lounis, Azzedine; Benmhidi, Kamel

    In the first part we have observed the electrotransport of molybdenum in carbonate media (OH-,CO=3) through a commercial electrodialysis anion exchange membrane. The values of the molybdenum, hydrogen oxide and carbonate fluxes obtained in this study show that molybdenum is present as molybdate ion MoO=4 in carbonate solution and that the molybdyl tricarbonate ion existence hypothesis MoO2(CO3)4-3 an't no longer be maintained. In order to confirm this result we have studied the electrotransport of molybdenum and carbonate ions with different CO=3/MoO=4 ratio. The used theory is based on the fact that, the concentration ratio in the membrane equals the one of the same species within the solution. These hypothesis have to be justified given that this equality is actually usual for unstirred layers extremity. Therefore, in the second part the concentration and the potential profiles in aqueous interfacial layers were determined by a numerical resolution of the Nernst-Planck electrodiffusion equation coupled with the Poisson equation. The obtained concentration profiles from numerical resolution differ from 3 to 6% from the ones acquired by analytical resolution method assuming the constant electrical field hypothesis for OH-, CO=3 ions, respectively. However the potential profiles display that constant electrical field hypothesis is strictly valid.

  17. Real space analysis of Compton profile of Heusler alloy Ni2TiAl

    NASA Astrophysics Data System (ADS)

    Sahariya, Jagrati; Mund, H. S.; Ahuja, B. L.

    2012-06-01

    Electron momentum density of Ni2TiAl alloy has been studied using Compton scattering technique. The experiment has been performed using 20 Ci 137Cs (661.65 keV) Compton spectrometer at an intermediate resolution of 0.34 a.u. To interpret the experimental data, we have calculated the Compton profiles using Hartree Fock and density functional theories within the frame work of linear combination of atomic orbitals (LCAO) method. The experimental data have been interpreted in term of autocorrelation function B(z) of the one electron wave function. The experimental B(z) function has been compared with the LCAO based theoretical B(z), to analyze the electronic and structural properties of Ni2TiAl.

  18. Effect of ozone concentration on silicon surface passivation by atomic layer deposited Al2O3

    NASA Astrophysics Data System (ADS)

    von Gastrow, Guillaume; Li, Shuo; Putkonen, Matti; Laitinen, Mikko; Sajavaara, Timo; Savin, Hele

    2015-12-01

    We study the impact of ozone-based Al2O3 Atomic Layer Deposition (ALD) on the surface passivation quality of crystalline silicon. We show that the passivation quality strongly depends on the ozone concentration: the higher ozone concentration results in lower interface defect density and thereby improved passivation. In contrast to previous studies, our results reveal that too high interface hydrogen content can be detrimental to the passivation. The interface hydrogen concentration can be optimized by the ozone-based process; however, the use of pure ozone increases the harmful carbon concentration in the film. Here we demonstrate that low carbon and optimal hydrogen concentration can be achieved by a single process combining the water- and ozone-based reactions. This process results in an interface defect density of 2 × 1011 eV-1 cm-2, and maximum surface recombination velocities of 7.1 cm/s and 10 cm/s, after annealing and after an additional firing at 800 °C, respectively. In addition, our results suggest that the effective oxide charge density can be optimized in a simple way by varying the ozone concentration and by injecting water to the ozone process.

  19. Reduced Cu concentration in CuAl-LPE-grown thin Si layers

    SciTech Connect

    Wang, T.H.; Ciszek, T.F.; Asher, S.; Reedy, R.

    1995-08-01

    Cu-Al has been found to be a good solvent system to grow macroscopically smooth Si layers with thicknesses in tens of microns on cast MG-Si substrates by liquid phase epitaxy (LPE) at temperatures near 900{degrees}C. This solvent system utilizes Al to ensure good wetting between the solution and substrate by removing silicon native oxides, and employs Cu to control Al doping into the layers. Isotropic growth is achieved because of a high concentration of solute silicon in the solution and the resulting microscopically rough interface. The incorporation of Cu in the Si layers, however, was a concern since Cu is a major solution component and is generally regarded as a bad impurity for silicon devices due to its fast diffusivity and deep energy levels in the band gap. A study by Davis shows that Cu will nonetheless not degrade solar cell performance until above a level of 10{sup 17} cm{sup -3}. This threshold is expected to be even higher for thin layer silicon solar cells owing to the less stringent requirement on minority carrier diffusion length. But to ensure long term stability of solar cells, lower Cu concentrations in the thin layers are still preferred.

  20. Microscopic potential fluctuations in Si-doped AlGaN epitaxial layers with various AlN molar fractions and Si concentrations

    NASA Astrophysics Data System (ADS)

    Kurai, Satoshi; Miyake, Hideto; Hiramatsu, Kazumasa; Yamada, Yoichi

    2016-01-01

    Nanoscopic potential fluctuations of Si-doped AlGaN epitaxial layers with the AlN molar fraction varying from 0.42 to 0.95 and Si-doped Al0.61Ga0.39N epitaxial layers with Si concentrations of 3.0-37 × 1017 cm-3 were investigated by cathodoluminescence (CL) imaging combined with scanning electron microscopy. The spot CL linewidths of AlGaN epitaxial layers broadened as the AlN molar fraction was increased to 0.7, and then narrowed at higher AlN molar fractions. The experimental linewidths were compared with the theoretical prediction from the alloy broadening model. The trends displayed by our spot CL linewidths were consistent with calculated results at AlN molar fractions of less than about 0.60, but the spot CL linewidths were markedly broader than the calculated linewidths at higher AlN molar fractions. The dependence of the difference between the spot CL linewidth and calculated line broadening on AlN molar fraction was found to be similar to the dependence of reported S values, indicating that the vacancy clusters acted as the origin of additional line broadening at high AlN molar fractions. The spot CL linewidths of Al0.61Ga0.39N epitaxial layers with the same Al concentration and different Si concentrations were nearly constant in the entire Si concentration range tested. From the comparison of reported S values, the increase of VAl did not contribute to the linewidth broadening, unlike the case of the VAl clusters.

  1. The cognitive profile of ALS: a systematic review and meta-analysis update.

    PubMed

    Beeldman, Emma; Raaphorst, Joost; Klein Twennaar, Michelle; de Visser, Marianne; Schmand, Ben A; de Haan, Rob J

    2016-06-01

    Cognitive impairment is present in approximately 30% of patients with amyotrophic lateral sclerosis (ALS) and, especially when severe, has a negative impact on survival and caregiver burden. Our 2010 meta-analysis of the cognitive profile of ALS showed impairment of fluency, executive function, language and memory. However, the limited number of studies resulted in large confidence intervals. To obtain a more valid assessment, we updated the meta-analysis and included methodological improvements (controlled data extraction, risk of bias analysis and effect size calculation of individual neuropsychological tests). Embase, Medline and PsycInfo were searched for neuropsychological studies of non-demented patients with ALS and age-matched and education-matched healthy controls. Neuropsychological tests were categorised in 13 cognitive domains and effect sizes (Hedges' g) were calculated for each domain and for individual tests administered in ≥5 studies. Subgroup analyses were performed to assess the influence of clinical and demographic variables. Forty-four studies were included comprising 1287 patients and 1130 healthy controls. All cognitive domains, except visuoperceptive functions, showed significant effect sizes compared to controls. Cognitive domains without bias due to motor impairment showed medium effect sizes (95% CI): fluency (0.56 (0.43 to 0.70)), language (0.56 (0.40 to 0.72)), social cognition (0.55 (0.34 to 0.76)), or small effect sizes: delayed verbal memory 0.47 (0.27 to 0.68)) and executive functions (0.41 (0.27 to 0.55)). Individual neuropsychological tests showed diverging effect sizes, which could be explained by bias due to motor impairment. Subgroup analyses showed no influence of bulbar disease onset and depression and anxiety on the cognitive outcomes. The cognitive profile of ALS consists of deficits in fluency, language, social cognition, executive functions and verbal memory. Social cognition is a new cognitive domain with a relatively

  2. Flame Sprayed Al-12Si Coatings for the Improvement of the Adhesion of Composite Casting Profiles

    NASA Astrophysics Data System (ADS)

    Voyer, Joël; Peterlechner, Christian; Noster, Ulf

    2008-12-01

    In this study, flame sprayed Al-12Si coatings were produced on the surface of inlays (aluminum profiles) of composite castings parts. The aim was to enhance the strength between the joining partners inlay and cast. Due to the high surface roughness and the presence of pores in the coatings, combined with the formation of an intermetallic phase at the interface, the adhesion of flame sprayed inlays could be enhanced by a factor of 2 compared to blank inlays and by a factor of 1.3 when compared to sand-blasted inlays. However, results also show that gaps are present, mostly at the interface between the inlays and the flame sprayed coatings, and these gaps have a negative effect on the joining strength of the composite casting parts. Therefore, optimizing the adhesion of the coating on the Al profiles via an improvement in both the sand-blasting and the flame spraying parameters would be beneficial for further enhancement of the adhesion of composite casting parts.

  3. Tri-Lateral Noor al Salaam High Concentration Solar Central Receiver Program

    SciTech Connect

    Blackmon, James B

    2008-03-31

    This report documents the efforts conducted primarily under the Noor al Salaam (“Light of Peace”) program under DOE GRANT NUMBER DE-FC36-02GO12030, together with relevant technical results from a closely related technology development effort, the U.S./Israel Science and Technology Foundation (USISTF) High Concentration Solar Central Receiver program. These efforts involved preliminary design, development, and test of selected prototype power production subsystems and documentation of an initial version of the system definition for a high concentration solar hybrid/gas electrical power plant to be built in Zaafarana, Egypt as a first step in planned commercialization. A major part of the planned work was halted in 2007 with an amendment in October 2007 requiring that we complete the technical effort by December 31, 2007 and provide a final report to DOE within the following 90 days. This document summarizes the work conducted. The USISTF program was a 50/50 cost-shared program supported by the Department of Commerce through the U.S./Israel Science and Technology Commission (USISTC). The USISTC was cooperatively developed by President Clinton and the late Prime Minister Rabin of Israel "to encourage technological collaboration" and "support peace in the Middle East through economic development". The program was conducted as a follow-on effort to Israel's Magnet/CONSOLAR Program, which was an advanced development effort to design, fabricate, and test a solar central receiver and secondary optics for a "beam down" central receiver concept. The status of these hardware development programs is reviewed, since they form the basis for the Noor al Salaam program. Descriptions are provided of the integrated system and the major subsystems, including the heliostat, the high temperature air receiver, the power conversion unit, tower and tower reflector, compound parabolic concentrator, and the master control system. One objective of the USISTF program was to conduct

  4. Carbon substrate utilisation profile of a high concentration effluent degrading microbial consortium.

    PubMed

    Jena, S; Jeanmeure, L F C; Wichukorn, S D; Wright, P C

    2006-08-01

    This paper presents the carbon substrate utilisation profile of a group of microorganisms responsible for the biodegradation of a highly concentrated industrial effluent. A 1 litre bioreactor was used to study this consortium's biodegradation potential, with the chemical oxygen demand (COD) of the waste being reduced by 90% from 24000 mg l(-1) within 456 hours. This study also demonstrates that the consortium is capable of degrading organic solvents, such as isopropanol, at concentrations of 260 mg l(-1). The population distribution and biochemical behaviour were also characterised using denaturing gradient gel electrophoresis (DGGE) and Biolog Eco Plates at various stages of bioreactor operation. The DGGE results indicated that the dominant bands of the microbial population profile were stable at various operational stages, and that only a few bands varied with time. Moreover, four Biolog Eco plates were inoculated with samples drawn from the bioreactor at 0, 24, 72 and 120 hours after inoculation. Based on this Biolog Eco Plate profiling, a carbon source utilisation analysis was conducted to group the substrates according to their colour development patterns. Patterns were quantified via measurement of well optical density. Subsequently, cross-correlation statistical techniques were used to establish the existence of recurrent behavioural responses from each carbon source to the various wastewater samples. From the cross correlation, an attempt was made to classify the metabolic potential for future biodegradation processes. Carbohydrates, amino acids and carboxylic acids were the most predominant groups of sole carbon substrates showing similar growth behaviour in the consortium. PMID:16972382

  5. AMS method for depth profiling of trace elements concentration in materials - Construction and applications

    NASA Astrophysics Data System (ADS)

    Stan-Sion, C.; Enachescu, M.

    2015-10-01

    The need to investigate the behavior of solid state materials on the impact/retention/repulsion/contamination/impregnation with special trace elements or radioactive elements has driven us to develop a modified Accelerator Mass Spectrometry (AMS) analyzing method that is able to perform the measurement of the concentration depth profile of an element in a host material. This upgraded method that we call AMS-depth profiling method (AMS-DP) measures continuously the concentration of a trace element in a given sample material as a function of the depth from the surface (e.g., tritium in carbon, deuterium in tungsten, etc.). However, in order to perform depth profiling, common AMS facilities have to undergo several changes: a new replaceable sample target-holder has to be constructed to accept small plates of solid material as samples; their position has to be adjusted in the focus point of the sputter beam; crater rim effects of the produced hole in the sample have to be avoided or removed from the registered events in the detector; suitable reference samples have to be prepared and used for calibration. All procedures are presented in the paper together with several applications.

  6. Concentration profiles of metals in breast milk, drinking water, and soil: relationship between matrices.

    PubMed

    Cardoso, Osmar O; Julião, Fabiana C; Alves, Renato I S; Baena, Antonio R; Díez, Isabel G; Suzuki, Meire N; Celere, Beatriz S; Nadal, Martí; Domingo, José L; Segura-Muñoz, Susana I

    2014-07-01

    The concentrations of Cd, Cr, Cu, Hg, Mn, Ni, Pb, Sn, and Zn were determined in breast milk of women living in Conceição das Alagoas, Minas Gerais, Brazil. The potential relationships between metal levels in samples of breast milk, drinking water, and soils collected in the study area were also established. Metal levels in breast milk, except Cr, were lower in comparison to WHO reference concentrations. Zinc was the predominant element in breast milk and drinking water samples, with a median level of 46.2 and 82.2 μg · L(-1), respectively. Soils presented a different pattern of metal concentrations with respect to those found in breast milk and drinking water, Chromium showed the highest median levels (148 mg · kg(-1)), while a certain predominance of Zn and Cu was also observed (47.0 and 43.0 mg · kg(-1), respectively). Similar profiles were observed when comparing metal concentrations in drinking water and breast milk (chi-square χ(2) = 14.36; p < 0.05). In contrast, breast milk-soil and drinking water-soil metal concentration profiles showed significant differences (χ(2) = 635.05 and χ(2) = 721.78, respectively; p < 0.05). These results indicate that drinking water is an important exposure pathway for metals to newborns through breast milk. Further studies should be aimed at assessing the body burdens of metals in that population and at evaluating the potential relationships in the concentrations in biological and environmental matrices as well as at estimating the contribution of dietary intake of metals. In addition, the presence of other chemical pollutants in breast milk should be also studied in order to assess the combined newborn exposure to other contaminants. PMID:24881955

  7. Influence of dose and ion concentration on formation of binary Al-Ni alloy nanoclusters

    NASA Astrophysics Data System (ADS)

    Abedini, Alam; Larki, Farhad; Saion, Elias; Zakaria, Azmi; Zobir Hussein, M.

    2012-10-01

    Colloidal Al-Ni nanoclusters were prepared in an aqueous polyvinyl alcohol solution containing aluminum chloride and nickel chloride as metal precursors, polyvinyl alcohol as a capping agent, isopropanol as a scavenger of hydroxyl radicals, and distilled water as a solvent. Gamma irradiations were carried out in a 60Co gamma source chamber at doses up to 100 kGy. The nanocluster properties were characterized by transmission electron microscopy (TEM), UV-visible spectrophotometry, and X-ray diffraction (XRD). By controlling the dose and precursor concentration, nanoclusters with different particle sizes were obtained. The average particle diameter increased with increase of precursor concentration and decreased with increase of dose. This is owing to the competition between nucleation, growth, and aggregation processes in the formation of nanoclusters during irradiation.

  8. Diffusion-controlled spherulite growth in obsidian inferred from H2O concentration profiles

    SciTech Connect

    Watkins, Jim; Watkins, Jim; Manga, Michael; Huber, Christian; Martin, Michael C.

    2007-11-02

    Spherulites are spherical clusters of radiating crystals that occur naturally in rhyolitic obsidian. The growth of spherulites requires diffusion and uptake of crystal forming components from the host rhyolite melt or glass, and rejection of non-crystal forming components from the crystallizing region. Water concentration profiles measured by synchrotron-source Fourier transform spectroscopy reveal that water is expelled into the surrounding matrix during spherulite growth, and that it diffuses outward ahead of the advancing crystalline front. We compare these profiles to models of water diffusion in rhyolite to estimate timescales for spherulite growth. Using a diffusion-controlled growth law, we find that spherulites can grow on the order of days to months at temperatures above the glass transition. The diffusion-controlled growth law also accounts for spherulite size distribution, spherulite growth below the glass transition, and why spherulitic glasses are not completely devitrified.

  9. Transient flow of highly concentrated suspensions investigated using the ultrasound velocity profiler pressure difference method

    NASA Astrophysics Data System (ADS)

    Ouriev (Ur'ev), Boris; Windhab, Erich

    2003-11-01

    In the present work, the transient pressure driven shear flow of highly concentrated suspensions was investigated. The authors applied a novel Doppler-based ultrasound velocity profiler (Met-Flow SA)-pressure difference (UVP-PD) methodology (Ouriev B 2000 PhD Thesis Zurich ISBN: 3-905609-11-8, Ouriev B and Windhab E 2002 J. Exp. Fluids 32 204-11), for the investigation of concentrated suspensions in steady and transient flows. Model suspensions with two different solid phase concentrations and fluid matrixes were analysed in shear steady flow at different volumetric flow rates. Transient flow was initiated by abrupt flow interruption. Simultaneous recording of the pressure gradient (Windhab E 1986 Thesis VDI) and real time flow velocity profiles enables analyses of transient rheological flow properties. Both velocity and rheological information were simultaneously measured on-line and evaluated off-line. The rheological characteristics of the suspensions in transient flow are compared with those in steady flow and conclusions are drawn.

  10. Time and spatial concentration profile inside a membrane by means of a memory formalism

    NASA Astrophysics Data System (ADS)

    Caputo, Michele; Cametti, Cesare; Ruggero, Vittorio

    2008-03-01

    In this note, the profile concentration of diffusing particles inside a membrane has been calculated on the basis of the Fick diffusion equation modified by introducing a memory formalism. In highly heterogeneous systems, such as biological membranes, the intrinsic structural complexity of the medium restricts the applicability of continuum diffusion models and suggests that diffusion parameters could depend at a certain time or position on what happens at preceding times (diffusion with memory). Here, we deal with two particular cases, the diffusion of glucose across an erythrocyte membrane, when the concentration at both sides of the membrane are assigned, and the permeation transport of small molecular weight solute through an artificial hydrogel polymeric membrane. However, the present procedure can be easily extended to more general conditions. The knowledge of the concentration profile within a membranous structure, which is usually not easily experimentally accessible, completes the description of the rather complex phenomenon of the transport across a highly structured confined medium and can also lead to an improvement in controlled drug-delivery systems.

  11. A Direct Detection 1.6μm DIAL with Three Wavelengths for Measurements of Vertical CO2 Concentration and Temperature Profiles in the Atmosphere

    NASA Astrophysics Data System (ADS)

    Nagasawa, C.; Abo, M.; Shibata, Y.; Nagai, T.; Tsukamoto, M.

    2012-12-01

    We report the new 1.6 μm DIAL system that can measure the temperature profiles with the CO2 concentration profiles in the atmosphere because of improvement of measurement accuracy of the CO2 density and mixing ratio (ppm). We have developed a direct detection 1.6 μm differential absorption lidar (DIAL) technique to perform range-resolved measurements of vertical CO2 concentration profiles in the atmosphere [Sakaizawa et al. 2009]. Our 1.6 μm DIAL system consists of the Optical Parametric Generator (OPG) transmitter that excited by the LD pumped Nd:YAG laser with high repetition rate (500 Hz) and the receiving optics that included the near-infrared photomultiplier tube with high quantum efficiency operating at the photon counting mode and the telescope with larger aperture than that of the coherent detection method. Laser beams of three wavelengths around a CO2 absorption line is transmitted alternately to the atmosphere for measurements of CO2 concentration and temperature profiles. Moreover, a few retrieval algorithms of CO2-DIAL are also performed for improvement of measurement accuracy. The accurate vertical CO2 profiles in the troposphere are highly desirable in the inverse techniques to improve quantification and understanding of the global budget of CO2 and also global climate changes [Stephens et al. 2007]. In comparison with the ground-based monitoring network, CO2 measurements for vertical profiles in the troposphere have been limited to campaign-style aircraft and commercial airline observations with the limited spatial and temporal coverage. This work was financially supported by the System Development Program for Advanced Measurement and Analysis of the Japan Science and Technology Agency. References Sakaizawa, D., C. Nagasawa, T. Nagai, M. Abo, Y. Shibata, H. Nagai, M. Nakazato, and T. Sakai, Development of a 1.6μm differential absorption lidar with a quasi-phase-matching optical parametric oscillator and photon-counting detector for the vertical

  12. Estimation of Soil Radon Concentration in Al-Qateef's Date Palm Farms, Saudi Arabia

    SciTech Connect

    Al-Ghamdi, S. S.; Al-Garawi, M. S.; Baig, M. R.; Al-Sameen, M.

    2011-10-27

    This study involves the measurement of radon concentrations in agricultural soil from two date Palm farms in Al-Qateef province using CR-39 detector. In each farm the palm trees are arranged in rows separated by the irrigation reservoirs. The first farm is about 10000 m{sup 2} and has 350 palm trees and the second farm is about 7000 m{sup 2} and has 320 palm trees. The average distance between trees is about 5.5 m. The rows are separated by an irrigation reservoir where fertilizers are added. Sixty soil samples were collected from each farm and classified in paperboard boxes. These samples were taken from different depths and positions between the trees and from the irrigation reservoir.A newly designed tag type dosimeter is used in which the alpha tracks are registered on both sides of the CR-39 detector. The tag dosimeter was calibrated against a cup type dosimeter which was calibrated at the National Radiological Protection Board (NRPB) at the U.K.The detectors were left to count for five months and then chemically treated in the standard way. Finally an optical microscope is used to count alpha tracks and the data are treated statistically.The study is set to test for significant differences in radon concentrations at different positions and depths in the barren and fertilized soils in the two farms. Measured radon concentrations ranged between 42 and 344Bq/m{sup 3}. No significant difference between the mean concentration values in soil samples taken between the trees and that taken at the depth of 50 cm from the irrigation reservoir. Significant difference was however found between radon concentrations in samples collected directly from the surface of the irrigation reservoir where fertilizers are introduced and those taken from the other two positions. The used fertilizers are found to have higher contents of uranium which is limited to the surface soil of the irrigation reservoir.

  13. Circulating Irisin Concentrations Are Associated with a Favourable Lipid Profile in the General Population

    PubMed Central

    Oelmann, Simon; Nauck, Matthias; Völzke, Henry; Bahls, Martin; Friedrich, Nele

    2016-01-01

    Background/aims Irisin is a myokine, which is mainly inversely associated with the risk for non-communicable diseases. Irisin improves cellular energy metabolism by uncoupling the mitochondrial respiratory chain resulting in increased energy expenditure using lipids. To date potential associations between irisin concentration and lipid profile are poorly understood. Therefore, this investigation aimed to evaluate potential associations between irisin and lipid levels in the general population. Methods Data of 430 men and 537 women from the population-based Study of Health in Pomerania (SHIP-TREND) with available irisin and lipid concentrations were used. Analyses of variance, linear and logistic regression models adjusted for age, HBA1c, waist circumference, physical activity, smoking, alcohol consumption, systolic blood pressure, ALAT were calculated. Results We detected significantly inverse associations between irisin and circulating levels of total [beta coefficient 0.21 (standard error 0.08), p = 0.01], low-density cholesterol [-0.16 (0.07), p = 0.03] and triglycerides [-0.17 (0.08), p = 0.02] for men. Females without lipid lowering medication had an inverse association between irisin and total cholesterol [-0.12 (0.06), p = 0.05]. Further, male subjects with irisin concentrations in the third tertile had an increased odds for elevated low-density cholesterol [odds ratio 1.96 (95% confidence interval 1.07–3.48), p = 0.03) and triglyceride [1.95 (1.09–3.47), p = 0.02] levels, even after exclusion of subjects with lipid lowering medication. In addition, our data revealed an annual rhythm of serum irisin levels with peak levels arise in winter and summer months. Conclusion This is the first investigation to report a significant association between circulating irisin and a favourable lipid profile in the general population. This may infer that higher irisin concentrations are associated with a reduced risk for non-communicable diseases. PMID:27128661

  14. Concentration levels and congener profiles of polychlorinated biphenyls, pentachlorobenzene, and hexachlorobenzene in commercial pigments.

    PubMed

    Anezaki, Katsunori; Nakano, Takeshi

    2014-01-01

    The concentration levels and congener profiles of polychlorinated biphenyls (PCBs), pentachlorobenzene (PeCBz), and hexachlorobenzene (HxCBz) were assessed in commercially available organic pigments. Among the azo-type pigments tested, PCB-11, which is synthesized from 3,3'-dichlorobendizine, and PCB-52, which is synthesized from 2,2',5,5'-tetrachlorobendizine, were the major congeners detected. It is speculated that these were byproducts of chlorobendizine, which has a very similar structure. The total PCB concentrations in this type of pigment ranged from 0.0070 to 740 mg/kg. Among the phthalocyanine-type pigments, highly chlorinated PCBs, mainly composed of PCB-209, PeCBz, and HxCBz were detected. Their concentration levels ranged from 0.011 to 2.5 mg/kg, 0.0035 to 8.4 mg/kg, and 0.027 to 75 mg/kg, respectively. It is suggested that PeCBz and HxCBz were formed as byproducts and converted into PCBs at the time of synthesizing the phthalocyanine green. For the polycyclic-type pigments that were assessed, a distinctive PCB congener profile was detected that suggested an impact of their raw materials and the organic solvent used in the pigment synthesis. PCB pollution from PCB-11, PCB-52, and PCB-209 pigments is of particular concern; therefore, the monthly variations in atmospheric concentrations of these pollutants were measured in an urban area (Sapporo city) and an industrial area (Muroran city). The study detected a certain level of PCB-11, which is not included in PCB technical mixtures, and revealed continuing PCB pollution originating from pigments in the ambient air. PMID:23852585

  15. Profiles of Trace Gas Concentrations in Undisturbed Forest in the Brazilian Amazon

    NASA Astrophysics Data System (ADS)

    Carmo, J.; Crill, P.; Dias, J.; Camargo, P.; Keller, M.

    2004-12-01

    Globally, upland tropical forests are the largest natural source of nitrous oxide (N2O). Soils of upland tropical forests generally consume methane (CH4) although this process has only a minor effect on the atmospheric CH4 budget. In this study, we investigate the concentrations of N2O, CH4, and carbon dioxide (CO2) measured in profiles on towers in undisturbed forest at three Amazon forest sites located in the municipalities of Manaus, Amazonas, Melgaço, Para (Caxiuana), and Sinop, Mato Grosso. We measured gas concentration profiles at six heights above the ground on during both wet and dry seasons in 2003 and 2004. Nylon tubes (0.95 cm OD) were installed on towers used for meteorological and flux measurements in LBA. Gas samples were drawn through teflon filters (1μ m pore size) to a manifold and directed either to an infra-red gas analyzer (LiCor IRGA Model 6262), to sampling canisters, or to exhaust. During sampling periods, we maintained a continuous flow of at least 1 L min-1 through all sampling tubes. CO2 concentration data from the IRGA were recorded continuously using a Datastick analog to digital converter and a palm top computer. We removed air samples in electro-polished stainless steel canisters for off-site analysis of N2O and CH4 by ECD and FID gas chromatography respectively. Sampling times were selected based upon real-time measurements of CO2 concentration. Relatively stable meteorological conditions at night led to consistent increases in CO2 concentrations. At times we also observed increases in the concentrations of CH4 and N2O concentrations correlated with increasing CO2. The source of the increasing CO2 is most likely respiration by soil and above-ground organisms. Correlated increases in CH4 and N2O concentrations also likely result from biological activity in the soil and the canopy layer of the studied forests. Concentrations of these gases increase at night because the rate of gas emission in the canopy layer exceeds the rates of

  16. Using deconvolution to understand the mechanism for variable plasma concentration-time profiles after intramuscular injection.

    PubMed

    Mahmood, Adnan H; Liu, Xin; Grice, Jeffrey E; Medley, Gregory A; Roberts, Michael S

    2015-03-15

    To introduce better antibiotics for the treatment of some infectious diseases in sheep and to expand the range of antibiotics available for veterinary medicine, pharmacokinetics of two antibiotics marbofloxacin (MBX) and trovafloxacin (TVX) were investigated in sheep after intramuscular injection. Variable and irregular plasma concentration-time profiles were observed for TVX but not for MBX. To understand the mechanism of this phenomenon, intravenous studies were performed for both drugs and data were analyzed using a population approach. Deconvolution was then performed using various approaches to obtain absorption profiles of both drugs in sheep after intramuscular injection. The Loo-Riegelman and staircase deconvolution function methods were found to provide more reliable estimates of absorption rate than the Spath-spline and B-spline constraining break points deconvolution methods. The absorption profiles resulting from deconvolution indicated a zero-order absorption process for TVX and a first-order process for MBX. Precipitation of TVX at the injection site was suspected to cause the pseudo zero-order absorption. This hypothesis was supported by the observation of crystalline deposits of TVX in sheep meat after direct injection, using reflectance confocal microscopy. PMID:25636300

  17. Riluzole prodrugs for melanoma and ALS: design, synthesis, and in vitro metabolic profiling

    PubMed Central

    McDonnell, Mark E.; Vera, Matthew D.; Blass, Benjamin E.; Pelletier, Jeffrey C.; King, Richard C.; Fernandez-Metzler, Carmen; Smith, Garry R.; Wrobel, Jay; Chen, Suzie; Reitz, Allen B.

    2012-01-01

    Riluzole (1) is an approved therapeutic for the treatment of ALS and has also demonstrated antimelanoma activity in metabotropic glutamate GRM1 positive cell lines, a mouse xenograft assay and human clinical trials. Highly variable drug exposure following oral administration among patients, likely due to variable first pass effects from heterogeneous CYP1A2 expression, hinders its clinical use. In an effort to mitigate effects of this clearance pathway and uniformly administer riluzole at efficacious exposure levels, several classes of prodrugs of riluzole were designed, synthesized, and evaluated in multiple in vitro stability assays to predict in vivo drug levels. The optimal prodrug would possess the following profile: stability while transiting the digestive system, stability towards first pass metabolism, and metabolic lability in the plasma releasing riluzole. (S)-O-Benzyl serine derivative 9 was identified as the most promising therapeutically acceptable prodrug. PMID:22892214

  18. MTBE concentration profiles near MTBE manufacturing plant: modeling approach and modeling uncertainty.

    PubMed

    Chang, Ken-Hui; Chen, Chien-Hung

    2009-06-01

    The methyl tert-butyl ether (MTBE) concentration profiles near a MTBE manufacturing plant were monitored on two occasions. The US EPA's atmospheric dispersion model (industrial source complex short-term) was used to model the ambient MTBE levels with the input of local meteorological data as well as MTBE emissions from the plant. The measured ambient MTBE concentrations range from 6 to 76 microgm(-3) with the average value about 33 microgm(-3). These values are similar to those values reported in ambient air in the vicinity of service stations of 4-12 microgm(-3) and tollbooths at a highway of 10-22 microgm(-3), but lower than those values reported in ambient air near gas stations of 50-690 microgm(-3), and higher than those values reported in atmospheric of 0.9-3.0 microgm(-3). Since the model has not been validated for the simulated MTBE profiles, there exist differences between the observed and mode-predicted data. The sensitivity and uncertainty of model parameters were then analyzed. The effects of wind direction, wind velocity and atmospheric stability are discussed in terms of their impact on model sensitivity/uncertainty. PMID:19342074

  19. Effect of Protein, Polysaccharide, and Oxygen Concentration Profiles on Biofilm Cohesiveness▿

    PubMed Central

    Ahimou, Francois; Semmens, Michael J.; Haugstad, Greg; Novak, Paige J.

    2007-01-01

    It is important to control biofilm cohesiveness to optimize process performance. In this study, a membrane-aerated biofilm reactor inoculated with activated sludge was used to grow mixed-culture biofilms of different ages and thicknesses. The cohesions, or cohesive energy levels per unit volume of biofilm, based on a reproducible method using atomic force microscopy (F. Ahimou, M. J. Semmens, P. J. Novak, and G. Haugstad, Appl. Environ. Microbiol. 73:2897-2904, 2007), were determined at different locations within the depths of the biofilms. In addition, the protein and polysaccharide concentrations within the biofilm depths, as well as the dissolved oxygen (DO) concentration profiles within the biofilms, were measured. It was found that biofilm cohesion increased with depth but not with age. Level of biofilm cohesive energy per unit volume was strongly correlated with biofilm polysaccharide concentration, which increased with depth in the membrane-aerated biofilm. In a 12-day-old biofilm, DO also increased with depth and may therefore be linked to polysaccharide production. In contrast, protein concentration was relatively constant within the biofilm and did not appear to influence cohesion. PMID:17337565

  20. Time-dependent stress concentration and microcrack nucleation in TiAl

    SciTech Connect

    Yoo, M.H.

    1995-07-01

    Localized stress evolution associated with the interaction of slip or twinning with an interface is treated by means of a superposition of the {open_quotes}internal loading{close_quotes} of a crystalline subsystem by dynamic dislocation pile-up and the stress relaxation by climb of interfacial dislocations. The peak value of a stress concentration factor depends on both the angular function that includes the effect of mode mixity and the ratio of characteristic times for stress relaxation and internal loading. The available experimental data on orientation and strain-rate dependences of interfacial fracture mode in polysynthetically twinned TiAl crystals are discussed in view of the theoretical concepts presented in this paper.

  1. [Measurements of CO2 Concentration Profile in Troposphere Based on Balloon-Borne TDLAS System].

    PubMed

    Yao, Lu; Liu, Wen-qing; Liu, Jian-guo; Kan, Rui-feng; Xu, Zhen-yu; Ruan, Jun; Yuan, Song

    2015-10-01

    The main source and sink of CO2 in the atmosphere are concentrated in the troposphere. It is of great significance to the study of CO2 flux and global climate change to obtain the accurate tropospheric CO2 concentration profile. For the characteristics of high resolution, high sensitivity and fast response of tunable diode laser absorption spectroscopy (TDLAS), a compact balloon-borne system based on direct absorption was developed to detect the CO2 concentration profiles by use of the 2 004. 02 nm, R(16), v1+v3 line without the interfere of H2O absorption and the CO2 density of the number of molecules below 10 km in the troposphere was obtained. Due to the balloon-borne environment, a compact design of one single board integrated with laser driver, signal conditioning, spectra acquiring and concentration retrieving was developed. Limited by the working capability and hardware resources of embedded micro-processor, the spectra processing algorithm was optimized to reduce the time-cost. Compared with the traditional TDLAS sensors with WMS technique, this system was designed based on the direct absorption technique by means of an open-path Herriott cell with 20 m optical-path, which avoided the process of standardization and enhanced the environmental adaptation. The universal design of hardware and software platform achieved diverse gas measuring by changing the laser and adjusting some key parameters in algorithm. The concept of compact design helped to reduce the system's power and volume and balanced the response speed and measure precision. The power consumes below 1.5 W in room temperature and the volume of the single board is 120 mm x 100 mm x 25 mm, and the measurement accuracy is ± 0.6 x 10(-6) at 1.5 s response time. It has been proved that the system can realize high precision detection of CO2 profile at 15 m vertical resolution in troposphere and TDLAS is an available method for balloon-borne detection. PMID:26904819

  2. Inhomogeneous distribution of defect-related emission in Si-doped AlGaN epitaxial layers with different Al content and Si concentration

    SciTech Connect

    Kurai, Satoshi Ushijima, Fumitaka; Yamada, Yoichi; Miyake, Hideto; Hiramatsu, Kazumasa

    2014-02-07

    The spatial distribution of luminescence in Si-doped AlGaN epitaxial layers that differ in Al content and Si concentration has been studied by cathodoluminescence (CL) mapping in combination with scanning electron microscopy. The density of surface hillocks increased with decreasing Al content and with increasing Si concentration. The mechanisms giving rise to those hillocks are likely different. The hillocks induced surface roughening, and the compositional fluctuation and local donor-acceptor-pair (DAP) emission at hillock edges in AlGaN epitaxial layers were enhanced irrespective of the origin of the hillocks. The intensity of local DAP emission was related to Si concentration, as well as to hillock density. CL observation revealed that DAP emission areas were present inside the samples and were likely related to dislocations concentrated at hillock edges. Possible candidates for acceptors in the observed DAP emission that are closely related in terms of both Si concentration and hillock edges with large deformations are a V{sub III}-Si{sub III} complex and Si{sub N}, which are unfavorable in ordinary III-nitrides.

  3. Experimental investigation of a nanofluid absorber employed in a low-profile, concentrated solar thermal collector

    NASA Astrophysics Data System (ADS)

    Li, Qiyuan; Zheng, Cheng; Mesgari, Sara; Hewakuruppu, Yasitha L.; Hjerrild, Natasha; Crisostomo, Felipe; Morrison, Karl; Woffenden, Albert; Rosengarten, Gary; Scott, Jason A.; Taylor, Robert A.

    2015-12-01

    Recent studies [1-3] have demonstrated that nanotechnology, in the form of nanoparticles suspended in water and organic liquids, can be employed to enhance solar collection via direct volumetric absorbers. However, current nanofluid solar collector experimental studies are either relevant to low-temperature flat plate solar collectors (<100 °C) [4] or higher temperature (>100 °C) indoor laboratory-scale concentrating solar collectors [1, 5]. Moreover, many of these studies involve in thermal properties of nanofluid (such as thermal conductivity) enhancement in solar collectors by using conventional selective coated steel/copper tube receivers [6], and no full-scale concentrating collector has been tested at outdoor condition by employing nanofluid absorber [2, 6]. Thus, there is a need of experimental researches to evaluate the exact performance of full-scale concentrating solar collector by employing nanofluids absorber at outdoor condition. As reported previously [7-9], a low profile (<10 cm height) solar thermal concentrating collector was designed and analysed which can potentially supply thermal energy in the 100-250 °C range (an application currently met by gas and electricity). The present study focuses on the design and experimental investigation of a nanofluid absorber employed in this newly designed collector. The nanofluid absorber consists of glass tubes used to contain chemically functionalized multi-walled carbon nanotubes (MWCNTs) dispersed in DI water. MWCNTs (average diameter of 6-13 nm and average length of 2.5-20 μm) were functionalized by potassium persulfate as an oxidant. The nanofluids were prepared with a MCWNT concentration of 50 +/- 0.1 mg/L to form a balance between solar absorption depth and viscosity (e.g. pumping power). Moreover, experimentally comparison of the thermal efficiency between two receivers (a black chrome-coated copper tube versus a MWCNT nanofluid contained within a glass tubetube) is investigated. Thermal

  4. The potential of LIRIC to validate the vertical profiles of the aerosol mass concentration estimated by an air quality model

    NASA Astrophysics Data System (ADS)

    Siomos, Nikolaos; Filoglou, Maria; Poupkou, Anastasia; Liora, Natalia; Dimopoulos, Spyros; Melas, Dimitris; Chaikovsky, Anatoli; Balis, Dimitris

    2015-04-01

    Vertical profiles of the aerosol mass concentration derived by a retrieval algorithm that uses combined sunphotometer and LIDAR data (LIRIC) were used in order to validate the mass concentration profiles estimated by the air quality model CAMx. LIDAR and CIMEL measurements of the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki were used for this validation.The aerosol mass concentration profiles of the fine and coarse mode derived by CAMx were compared with the respective profiles derived by the retrieval algorithm. For the coarse mode particles, forecasts of the Saharan dust transportation model BSC-DREAM8bV2 were also taken into account. Each of the retrieval algorithm's profiles were matched to the models' profile with the best agreement within a time window of four hours before and after the central measurement. OPAC, a software than can provide optical properties of aerosol mixtures, was also employed in order to calculate the angstrom exponent and the lidar ratio values for 355nm and 532nm for each of the model's profiles aiming in a comparison with the angstrom exponent and the lidar ratio values derived by the retrieval algorithm for each measurement. The comparisons between the fine mode aerosol concentration profiles resulted in a good agreement between CAMx and the retrieval algorithm, with the vertical mean bias error never exceeding 7 μgr/m3. Concerning the aerosol coarse mode concentration profiles both CAMx and BSC-DREAM8bV2 values are severely underestimated, although, in cases of Saharan dust transportation events there is an agreement between the profiles of BSC-DREAM8bV2 model and the retrieval algorithm.

  5. Gene expression profiling in Daphnia magna part I: concentration-dependent profiles provide support for the No Observed Transcriptional Effect Level.

    PubMed

    Poynton, Helen C; Loguinov, Alexandre V; Varshavsky, Julia R; Chan, Sarah; Perkins, Edward J; Vulpe, Chris D

    2008-08-15

    Ecotoxicogenomic approaches to environmental monitoring provide holistic information, offer insight into modes of action, and help to assess the causal agents and potential toxicity of effluents beyond the traditional end points of death and reproduction. Recent investigations of toxicant exposure indicate dose-dependent changes are a key issue in interpreting genomic studies. Additionally, there is interest in developing methods to integrate gene expression studies in environmental monitoring and regulation, and the No Observed Transcriptional Effect Level (NOTEL) has been proposed as a means for screening effluents and unknown chemicals fortoxicity. However, computational methods to determine the NOTEL have yet to be established. Therefore, we examined effects on gene expression in Daphnia magna following exposure to Cu, Cd, and Zn over a range of concentrations including a tolerated, a sublethal, and a nearly acutely toxic concentration. Each concentration produced a distinct gene expression profile. We observed differential expression of a very few genes at tolerated concentrations that were distinct from the expression profiles observed at concentrations associated with toxicity. These results suggest that gene expression analysis may offer a strategy for distinguishing toxic and nontoxic concentrations of metals in the environment and provide support for a NOTEL for metal exposure in D. magna. Mechanistic insights could be inferred from the concentration-dependent gene expression profiles including metal specific effects on disparate metabolic processes such as digestion, immune response, development and reproduction, and less specific stress responses at higher concentrations. PMID:18767695

  6. Nonlinear-approximation technique for determining vertical ozone-concentration profiles with a differential-absorption lidar

    NASA Astrophysics Data System (ADS)

    Kovalev, Vladimir A.; Bristow, Michael P.; McElroy, James L.

    1996-08-01

    A new technique is presented for the retrieval of ozone-concentration profiles (O 3 ) from backscattered signals obtained by a multiwavelength differential-absorption lidar (DIAL). The technique makes it possible to reduce erroneous local fluctuations induced in the ozone-concentration profiles by signal noise and other phenomena such as aerosol inhomogeneity. Before the O 3 profiles are derived, the dominant measurement errors are estimated and uncertainty boundaries for the measured profiles are established. The off- to on-line signal ratio is transformed into an intermediate function, and analytical approximations of the function are then determined. The separation of low- and high-frequency constituents of the measured ozone profile is made by the application of different approximation fits to appropriate intermediate functions. The low-frequency constituents are approximated with a low-order polynomial fit, whereas the high-frequency constituents are approximated with a trigonometric fit. The latter fit makes it possible to correct the measured O 3 profiles in zones of large ozone-concentration gradients where the low-order polynomial fit is found to be insufficient. Application of this technique to experimental data obtained in the lower troposphere shows that erroneous fluctuations induced in the ozone-concentration profile by signal noise and aerosol inhomogeneity undergo a significant reduction in comparison with the results from the conventional technique based on straightforward numerical differentiation.

  7. Nonlinear-approximation technique for determining vertical ozone-concentration profiles with a differential-absorption lidar.

    PubMed

    Kovalev, V A; Bristow, M P; McElroy, J L

    1996-08-20

    A new technique is presented for the retrieval of ozone-concentration profiles (O(3)) from backscattered signals obtained by a multiwavelength differential-absorption lidar (DIAL). The technique makes it possible to reduce erroneous local fluctuations induced in the ozone-concentration profiles by signal noise and other phenomena such as aerosol inhomogeneity. Before the O(3) profiles are derived, the dominant measurement errors are estimated and uncertainty boundaries for the measured profiles are established. The off- to on-line signal ratio is transformed into an intermediate function, and analytical approximations of the function are then determined. The separation of low- and high-frequency constituents of the measured ozone profile is made by the application of different approximation fits to appropriate intermediate functions. The low-frequency constituents are approximated with a low-order polynomial fit, whereas the high-frequency constituents are approximated with a trigonometric fit. The latter fit makes it possible to correct the measured O(3) profiles in zones of large ozone-concentration gradients where the low-order polynomial fit is found to be insufficient. Application of this technique to experimental data obtained in the lower troposphere shows that erroneous fluctuations induced in the ozone-concentration profile by signal noise and aerosol inhomogeneity undergo a significant reduction in comparison with the results from the conventional technique based on straightforward numerical differentiation. PMID:21102905

  8. Timescales of spherulite crystallization in obsidian inferred from water concentration profiles

    SciTech Connect

    Castro, Jonathan M.; Beck, Pierre; Tuffen, Hugh; Nichols, Alexander R.L.; Dingwell, Donald B.; Martin, Michael C

    2008-06-25

    We determined the kinetics of spherulite growth in obsidians from Krafla volcano, Iceland. We measured water concentration profiles around spherulites in obsidian by synchrotron Fourier transform infrared spectroscopy. The distribution of OH? groups surrounding spherulites decreases exponentially away from the spherulite-glass border, reflecting expulsion of water during crystallization of an anhydrous paragenesis (plagioclase + SiO2 + clinopyroxene + magnetite). This pattern is controlled by a balance between the growth rate of the spherulites and the diffusivity of hydrous solute in the rhyolitic melt. We modeled advective and diffusive transport of the water away from the growing spherulites by numerically solving the diffusion equation with a moving boundary. Numerical models fit the natural data best when a small amount of post-growth diffusion is incorporated in the model. Comparisons between models and data constrain the average spherulite growth rates for different temperatures and highlight size-dependent growth among a small population of spherulites.

  9. Mode of action classification of chemicals using multi-concentration time-dependent cellular response profiles.

    PubMed

    Xi, Zhankun; Khare, Swanand; Cheung, Aaron; Huang, Biao; Pan, Tianhong; Zhang, Weiping; Ibrahim, Fadi; Jin, Can; Gabos, Stephan

    2014-04-01

    In this paper, we present a new statistical pattern recognition method for classifying cytotoxic cellular responses to toxic agents. The advantage of the proposed method is to quickly assess the toxicity level of an unclassified toxic agent on human health by bringing cytotoxic cellular responses with similar patterns (mode of action, MoOA) into the same class. The proposed method is a model-based hierarchical classification approach incorporating principal component analysis (PCA) and functional data analysis (FDA). The cytotoxic cell responses are represented by multi-concentration time-dependent cellular response profiles (TCRPs) which are dynamically recorded by using the xCELLigence real-time cell analysis high-throughput (RTCA HT) system. The classification results obtained using our algorithm show satisfactory discrimination and are validated using biological facts by examining common chemical mechanisms of actions with treatment on human hepatocellular carcinoma cells (HepG2). PMID:24583602

  10. Measurement of the stratospheric hydrogen peroxide concentration profile using far infrared thermal emission spectroscopy

    NASA Technical Reports Server (NTRS)

    Chance, K. V.; Johnson, D. G.; Traub, W. A.; Jucks, K. W.

    1991-01-01

    The first unequivocal measurement of hydrogen peroxide in the stratosphere have been made, a concentration profile obtained from a balloon platform using Fourier transform thermal emission spectroscopy in the far infrared. Measurements were made using the 112/cm R-Q5 branch of the rotational-torsional spectrum, with some confirmation from the 94/cm R-Q4 branch. The volume mixing ratio of H2O2 is 1.6 x 10 to the -10th at 38.4 km, decreasing to 0.6 x 10 to the -10th at 23.8 km, with uncertainties of about 16 percent. These measurements are compared to a recent stratospheric model calculation.

  11. Influence of Al2O3 sol concentration on the microstructure and mechanical properties of Cu-Al2O3 composite coatings

    NASA Astrophysics Data System (ADS)

    Wei, Xiaojin; Yang, Zhendi; Tang, Ying; Gao, Wei

    2015-03-01

    Copper (Cu) is widely used as electrical conducting and contacting material. However, Cu is soft and does not have good mechanical properties. In order to improve the hardness and wear resistance of Cu, sol-enhanced Cu-Al2O3 nanocomposite coatings were electroplated by adding a transparent Al oxide (Al2O3) sol into the traditional electroplating Cu solution. It was found that the microstructure and mechanical properties of the nanocomposite coatings were largely influenced by the Al2O3 sol concentration. The results show that the Al2O3 nanoparticle reinforced the composite coatings, resulting in significantly improved hardness and wear resistance in comparison with the pure Cu coatings. The coating prepared at the sol concentration of 3.93 mol/L had the best microhardness and wear resistance. The microhardness has been improved by 20% from 145.5 HV (Vickers hardness number) of pure Cu coating to 173.3 HV of Cu-Al2O3 composite coatings. The wear resistance was also improved by 84%, with the wear volume loss dropped from 3.2 × 10-3 mm3 of Cu coating to 0.52 × 10-3 mm3 of composite coatings. Adding excessive sol to the electrolyte deteriorated the properties.

  12. Transmission electron microscopy investigation of oxidation of (110)NiAl single crystal with wedge-shaped profile

    NASA Astrophysics Data System (ADS)

    Fedchenko, Olena; Chernov, Sergey V.; Klimenkov, Michael; Protsenko, Serhiy I.; Nepijko, Sergej A.; Schönhense, Gerd

    2016-02-01

    Low energy electron diffraction (LEED), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray (EDX), and electron energy loss spectroscopy (EELS) investigations of oxidation processes in (110)NiAl single crystal of wedge like shape, i.e., on the sample’s areas of different thickness, were carried out. It was found that in the result of several cycles of ion etching, annealing and oxidation the upper layer of (110)NiAl is enriched with Ni. With the increase of Ni concentration from 50 to 100 at. %, the stoichiometry of the near surface area changes and the new phases of Ni3Al and Ni with Al doping are formed one after another. Up to Ni content of 75 at. % the defects concentration in the near-surface area increases and above 75 at. % it drops again. This leads to the change in orientation and azimuth direction of aluminum oxide (alumina). By varying the conditions of γ-Al2O3 epitaxial growth on (110)NiAl with (100), (110), and (111) orientations, we found that this oxide can be grown with different azimuthal directions, for example [440](111)γ-Al2O3 ∥ [002](110)NiAl and [440](111)γ-Al2O3 ∥ [022](110)NiAl.

  13. NONLINEAR-APPROXIMATION TECHNIQUE FOR DETERMINING VERTICAL OZONE-CONCENTRATION PROFILES WITH A DIFFERENTIAL-ABSORPTION LIDAR

    EPA Science Inventory

    A new technique is presented for the retrieval of ozone concentration profiles from backscattered signals obtained by a multi-wavelength differential-absorption lidar (DIAL). The technique makes it possible to reduce erroneous local fluctuations induced in the ozone-concentration...

  14. Effects of Li concentration and a Mg addition on serrated flow in Al-Li alloys

    SciTech Connect

    Zambo, S.J.; Wert, J.A. . Dept. of Materials Science and Engineering)

    1993-12-15

    Serrated flow phenomena have been reported in a variety of precipitation-strengthened aluminum alloys. In the particular case of precipitation-strengthened Al-Li alloys, serrated flow effects of similar character have been reported in binary Al-Li alloys and in commercial-type Al-Li alloys containing multiple alloying elements. Observations of serrated flow in binary Al-Li alloys indicate that the presence of Li alone is sufficient to produce serrated flow. Aging time has been used to probe the mechanisms that cause serrated flow in individual Al-Li alloys, and several investigators have noted that serrated flow disappears when Al-Li alloys are aged to peak strength or overaged. Much of the available experimental evidence supports dislocation-[delta][prime] interactions as the cause of serrated flow in Al-Li alloys, rather than dislocation-solute atom interactions to which serrated flow phenomena are traditionally attributed. Additional support for this conclusion could be provided by comparison of stress-strain curves for a solid solution Al-Li binary alloy of the same composition as the matrix phase of a precipitation-strengthened Al-Li binary alloy. The purpose of the present paper is to show stress--strain curves for Al-1.38Li, Al-1.80Li and Al-1.39Li-1.0Mg alloys, and to interpret the results in terms of the interactions proposed to account for serrated flow in Al-Li alloys.

  15. Application of PAH concentration profiles in lake sediments as indicators for smelting activity.

    PubMed

    Warner, Wiebke; Ruppert, Hans; Licha, Tobias

    2016-09-01

    The ability of lake sediment cores to store long-term anthropogenic pollution establishes them as natural archives. In this study, we focus on the influence of copper shale mining and smelting in the Mansfeld area of Germany, using the depth profiles of two sediment cores from Lake Süßer See. The sediment cores provide a detailed chronological deposition history of polycyclic aromatic hydrocarbons (PAHs) and heavy metals in the studied area. Theisen sludge, a fine-grained residue from copper shale smelting, reaches the lake via deflation by wind or through riverine input; it is assumed to be the main source of pollution. To achieve the comparability of absolute contaminant concentrations, we calculated the influx of contaminants based on the sedimentation rate. Compared to the natural background concentrations, PAHs are significantly more enriched than heavy metals. They are therefore more sensitive and selective for source apportionment. We suggest two diagnostic ratios of PAHs to distinguish between Theisen sludge and its leachate: the ratio fluoranthene to pyrene ~2 and the ratio of PAH with logKOW<5.7 to PAH with a logKOW>5.7 converging to an even lower value than 2.3 (the characteristic of Theisen sludge) to identify the particulate input in lake environments. PMID:27176930

  16. Stress Concentration and Fracture at Inter-variant Boundaries in an Al-Li Alloy

    NASA Technical Reports Server (NTRS)

    Crooks, Roy; Tayon, Wes; Domack, Marcia; Wagner, John; Beaudoin, Armand

    2009-01-01

    Delamination fracture has limited the use of lightweight Al-Li alloys. Studies of secondary, delamination cracks in alloy 2090, L-T fracture toughness samples showed grain boundary failure between variants of the brass texture component. Although the adjacent texture variants, designated B(sub s1) and B(sub s2), behave similarly during rolling, their plastic responses to mechanical tests can be quite different. EBSD data from through-thickness scans were used to generate Taylor factor maps. When a combined boundary normal and shear tensor was used in the calculation, the delaminating grains showed the greatest Taylor Factor differences of any grain pairs. Kernel Average Misorientation (KAM) maps also showed damage accumulation on one side of the interface. Both of these are consistent with poor slip accommodation from a crystallographically softer grain to a harder one. Transmission electron microscopy was used to confirm the EBSD observations and to show the role of slip bands in the development of large, interfacial stress concentrations. A viewgraph presentation accompanies the provided abstract.

  17. RADIAL COMBUSTION DYNAMICS IN Fe{sub 2}O{sub 3}/Al THERMITE: VARIABILITY OF THE FLAME PROPAGATION PROFILES

    SciTech Connect

    Duraes, L.; Portugal, A.; Plaksin, I.; Campos, J.; Antunes, J.

    2009-12-28

    In this work, the radial combustion in thin circular samples of stoichiometric and over aluminized Fe{sub 2}O{sub 3}/Al mixtures is studied. Two confinement materials are tested: stainless steel and PVC. The combustion front profiles are registered by digital video-crono-photography. The radial geometry allows an easy detection of sample heterogeneities, via the circularity distortions of the combustion front profiles. The influence of the Al content in the mixtures and the type of confinement on the combustion propagation dynamics is analyzed. Additionally, an asymmetry parameter of the combustion front profiles is defined and statistically treated via ANOVA. Although the type of confinement contributes more than the mixture composition to the variability of the asymmetry parameter, they both have a weak influence. The main source of variability is the intrinsic variations of the samples, which are due to their heterogeneous character.

  18. Radial Combustion Dynamics in Fe2O3/Al Thermite Mixtures: Variability of the Flame Propagation Profiles

    NASA Astrophysics Data System (ADS)

    Duraes, Luisa; Plaksin, Igor; Antunes, Jose; Campos, Jose; Portugal, Antonio

    2009-06-01

    Radial combustion in thin circular samples of stoichiometric and over aluminized Fe2O3/Al mixtures is studied. Two confinement materials are tested: stainless steel and PVC. The combustion front profiles are registered by digital video-crono-photography. The radial geometry allows an easy detection of sample heterogeneities, since they cause distortions on the combustion front profiles circularity. The influence of the mixtures Al content and type of confinement on the combustion propagation dynamics is analyzed. In addition, an asymmetry analysis of the combustion front profiles is performed, defining an asymmetry parameter and using ANOVA. Although the type of confinement contributes more than the mixture composition to the variability of the asymmetry parameter, they both have a weak influence. The main source of variability is the intrinsic variations of the samples, which are due to their heterogeneous character.

  19. Simultaneous enhancement of carrier mobility and concentration via tailoring of Al-chemical states in Al-ZnO thin films

    SciTech Connect

    Kumar, Manish Wen, Long; Sahu, Bibhuti B.; Han, Jeon Geon

    2015-06-15

    Simultaneously achieving higher carriers concentration and mobility is a technical challenge against up-scaling the transparent-conductive performances of transparent-conductive oxides. Utilizing one order higher dense (∼1 × 10{sup 11} cm{sup −3}) plasmas (in comparison to the conventional direct current plasmas), highly c-axis oriented Al-doped ZnO films have been prepared with precise control over relative composition and chemical states of constituting elements. Tailoring of intrinsic (O vacancies) and extrinsic (ionic Al and zero-valent Al) dopants provide simultaneous enhancement in mobility and concentration of charge carriers. Room-temperature resistivity as low as 4.89 × 10{sup −4} Ω cm along the carrier concentration 5.6 × 10{sup 20} cm{sup −3} is obtained in 200 nm thick transparent films. Here, the control of atomic Al reduces the charge trapping at grain boundaries and subdues the effects of grain boundary scattering. A mechanism based on the correlation between electron-hole interaction and carrier mobility is proposed for degenerately doped wide band-gap semiconductors.

  20. Simultaneous enhancement of carrier mobility and concentration via tailoring of Al-chemical states in Al-ZnO thin films

    NASA Astrophysics Data System (ADS)

    Kumar, Manish; Wen, Long; Sahu, Bibhuti B.; Han, Jeon Geon

    2015-06-01

    Simultaneously achieving higher carriers concentration and mobility is a technical challenge against up-scaling the transparent-conductive performances of transparent-conductive oxides. Utilizing one order higher dense (˜1 × 1011 cm-3) plasmas (in comparison to the conventional direct current plasmas), highly c-axis oriented Al-doped ZnO films have been prepared with precise control over relative composition and chemical states of constituting elements. Tailoring of intrinsic (O vacancies) and extrinsic (ionic Al and zero-valent Al) dopants provide simultaneous enhancement in mobility and concentration of charge carriers. Room-temperature resistivity as low as 4.89 × 10-4 Ω cm along the carrier concentration 5.6 × 1020 cm-3 is obtained in 200 nm thick transparent films. Here, the control of atomic Al reduces the charge trapping at grain boundaries and subdues the effects of grain boundary scattering. A mechanism based on the correlation between electron-hole interaction and carrier mobility is proposed for degenerately doped wide band-gap semiconductors.

  1. Active and Passive Microwave Retrieval Algorithm for Hydrometeor Concentration Profiles: Application to the HAMP Instrument

    NASA Astrophysics Data System (ADS)

    Orlandi, E.; Mech, M.; Crewell, S.; Lammert, A.

    2012-12-01

    Clouds and precipitation play an important role in the atmospheric water cycle and radiation budget. Unfortunately, the understanding of the processes involved in cloud and precipitation formation and their description in global and regional models are still poor. To improve our understanding of these processes and to reduce model uncertainties, new observation and retrieval techniques are needed. The upcoming Global Precipitation Mission (GPM) provides a combination of a 36 GHz cloud radar and a suite of passive microwave instruments. In the retrieval development process for this and other upcoming missions, airborne platforms are a useful tool to test the algorithms exploiting the synergy of active and passive microwave instruments, and to validate satellite retrievals. In this respect HAMP (Microwave Package for HALO, the High Altitude Long Range aircraft), consisting of a 36 GHz Doppler cloud radar and a 26-channel radiometer, is an ideal test-bed. HAMP radiometers have frequencies along absorption lines (22, 60, 118 and 183 GHz) and in window regions, overlapping with those of AMSU A and B. HAMP will participate in early 2013 in the dedicated remote sensing HALO mission NARVAL (Next-generation Aircraft Remote-sensing for VALidation studies). During NARVAL, the HALO payload will include a water vapor lidar and drop sondes in addition to HAMP. The NARVAL campaign will thus be a excellent opportunity to test a newly developed retrieval algorithm, which exploits the synergy between passive and active microwave observations. In this work we present a Bayesian algorithm to retrieve precipitation rate, liquid and frozen hydrometeor concentration, as well as temperature and humidity profiles from the synergetic use of active and passive microwave nadir observations. Temperature and humidity are derived solely from passive radiometer measurements while the combined cloud radar and radiometer observations are used to retrieve hydrometeor concentration profiles. Lidar

  2. Passivation of phosphorus diffused silicon surfaces with Al{sub 2}O{sub 3}: Influence of surface doping concentration and thermal activation treatments

    SciTech Connect

    Richter, Armin Benick, Jan; Kimmerle, Achim; Hermle, Martin; Glunz, Stefan W.

    2014-12-28

    Thin layers of Al{sub 2}O{sub 3} are well known for the excellent passivation of p-type c-Si surfaces including highly doped p{sup +} emitters, due to a high density of fixed negative charges. Recent results indicate that Al{sub 2}O{sub 3} can also provide a good passivation of certain phosphorus-diffused n{sup +} c-Si surfaces. In this work, we studied the recombination at Al{sub 2}O{sub 3} passivated n{sup +} surfaces theoretically with device simulations and experimentally for Al{sub 2}O{sub 3} deposited with atomic layer deposition. The simulation results indicate that there is a certain surface doping concentration, where the recombination is maximal due to depletion or weak inversion of the charge carriers at the c-Si/Al{sub 2}O{sub 3} interface. This pronounced maximum was also observed experimentally for n{sup +} surfaces passivated either with Al{sub 2}O{sub 3} single layers or stacks of Al{sub 2}O{sub 3} capped by SiN{sub x}, when activated with a low temperature anneal (425 °C). In contrast, for Al{sub 2}O{sub 3}/SiN{sub x} stacks activated with a short high-temperature firing process (800 °C) a significant lower surface recombination was observed for most n{sup +} diffusion profiles without such a pronounced maximum. Based on experimentally determined interface properties and simulation results, we attribute this superior passivation quality after firing to a better chemical surface passivation, quantified by a lower interface defect density, in combination with a lower density of negative fixed charges. These experimental results reveal that Al{sub 2}O{sub 3}/SiN{sub x} stacks can provide not only excellent passivation on p{sup +} surfaces but also on n{sup +} surfaces for a wide range of surface doping concentrations when activated with short high-temperature treatments.

  3. Comprehensive Profiling of Plasma Fatty Acid Concentrations in Young Healthy Canadian Adults

    PubMed Central

    Abdelmagid, Salma A.; Clarke, Shannon E.; Nielsen, Daiva E.; Badawi, Alaa; El-Sohemy, Ahmed; Mutch, David M.; Ma, David W. L.

    2015-01-01

    Circulating fatty acids (FA) are associated with a multitude of chronic diseases. However, a major gap in establishing such relationships is the lack of accepted fatty acid reference ranges representing healthy individuals. Data on validated FA reference ranges would provide a better understanding of study baseline measures and aid in the evaluation and interpretation of pharmaceutical or dietary interventions. Reference ranges for plasma FA levels have been reported in a few small studies and on a limited number of FA. Therefore, we determined the average and percentiles of a broad set of 61 FA (C14 - C24:1) from plasma total lipids from an ethnically diverse population of healthy young Canadian males and females (Total n = 826). Plasma concentrations of some of the major FA ranged from 0.3 to 4.1 mmol/L for palmitic acid, 0.1 to 1.0 mmol/L for stearic acid, 0.03 to 3.2 mmol/L for oleic acid, 0.2 to 5.0 mmol/L for linoleic acid (LA), 12.0 to 186.9 μmol/L for α-linolenic acid, and 7.2 to 237.5 μmol/L for docosahexaenoic acid (DHA). Males had significantly higher plasma concentrations of γ-linolenic acid (GLA) and n-3 docosapentaenoic acid and lower concentrations of palmitoleic acid, LA and DHA than females. Comparison of FA concentrations between Caucasians, East Asians and South Asians revealed that South Asians had significantly lower levels of palmitoleic acid (p < 0.01) and oleic acid (p = 0.01) while East Asians had lower levels of GLA (p = 0.02) and dihomo-γ-linolenic acid (p = 0.03). Overall, these data provide a comprehensive set of quantitative values that profiles a small cohort of Canadians which highlights the utility of establishing validated FA reference ranges that may be used to understand how deficient, suboptimal, or excess amounts of a given FA may be associated with chronic disease. PMID:25675440

  4. One year of Seaglider dissolved oxygen concentration profiles at the PAP site

    NASA Astrophysics Data System (ADS)

    Binetti, Umberto; Kaiser, Jan; Heywood, Karen; Damerell, Gillian; Rumyantseva, Anna

    2015-04-01

    Oxygen is one of the most important variables measured in oceanography, influenced both by physical and biological factors. During the OSMOSIS project, 7 Seagliders were used in 3 subsequent missions to measure a multidisciplinary suite of parameters at high frequency in the top 1000 m of the water column for one year, from September 2012 to September 2013. The gliders were deployed at the PAP time series station (nominally at 49° N 16.5° W) and surveyed the area following a butterfly-shaped path. Oxygen concentration was measured by Aanderaa optodes and calibrated using ship CTD O2 profiles during 5 deployment and recovery cruises, which were in turn calibrated by Winkler titration of discrete samples. The oxygen-rich mixed layer deepens in fall and winter and gets richer in oxygen when the temperature decreases. The spring bloom did not happen as expected, but instead the presence of a series of small blooms was measured throughout spring and early summer. During the summer the mixed layer become very shallow and oxygen concentrations decreased. A Deep Oxygen Maximum (DOM) developed along with a deep chlorophyll maximum during the summer and was located just below the mixed layer . At this depth, phytoplankton had favourable light and nutrient conditions to grow and produce oxygen, which was not subject to immediate outgassing. The oxygen concentration in the DOM was not constant, but decreased, then increased again until the end of the mission. Intrusions of oxygen rich water are also visible throughout the mission. These are probably due to mesoscale events through the horizontal transport of oxygen and/or nutrients that can enhance productivity, particularly at the edge of the fronts. We calculate net community production (NCP) by analysing the variation in oxygen with time. Two methods have been proposed. The classical oxygen budget method assumes that changes in oxygen are due to the sum of air-sea flux, isopycnal advection, diapycnal mixing and NCP. ERA

  5. Assessment of the effects of As(III) treatment on cyanobacteria lipidomic profiles by LC-MS and MCR-ALS.

    PubMed

    Marques, Aline S; Bedia, Carmen; Lima, Kássio M G; Tauler, Romà

    2016-08-01

    Cyanobacteria are a group of photosynthetic, nitrogen-fixing bacteria present in a wide variety of habitats such as freshwater, marine, and terrestrial ecosystems. In this work, the effects of As(III), a major toxic environmental pollutant, on the lipidomic profiles of two cyanobacteria species (Anabaena and Planktothrix agardhii) were assessed by means of a recently proposed method based on the concept of regions of interest (ROI) in liquid chromatography mass spectroscopy (LC-MS) together with multivariate curve resolution alternating least squares (MCR-ALS). Cyanobacteria were exposed to two concentrations of As(III) for a week, and lipid extracts were analyzed by ultrahigh-performance liquid chromatography/time-of-flight mass spectrometry in full scan mode. The data obtained were compressed by means of the ROI strategy, and the resulting LC-MS data sets were analyzed by the MCR-ALS method. Comparison of profile peak areas resolved by MCR-ALS in control and exposed samples allowed the discrimination of lipids whose concentrations were changed due to As(III) treatment. The tentative identification of these lipids revealed an important reduction of the levels of some galactolipids such as monogalactosyldiacylglycerol, the pigment chlorophyll a and its degradation product, pheophytin a, as well as carotene compounds such as 3-hydroxycarotene and carotene-3,3'-dione, all of these compounds being essential in the photosynthetic process. These results suggested that As(III) induced important changes in the composition of lipids of cyanobacteria, which were able to compromise their energy production processes. Graphical abstract Steps of the proposed LC-MS + MCR-ALS procedure. PMID:27311955

  6. Chemical weathering of a marine terrace chronosequence, Santa Cruz, California I: Interpreting rates and controls based on soil concentration-depth profiles

    USGS Publications Warehouse

    White, A.F.; Schulz, M.S.; Vivit, D.V.; Blum, A.E.; Stonestrom, D.A.; Anderson, S.P.

    2008-01-01

    The spatial and temporal changes in element and mineral concentrations in regolith profiles in a chronosequence developed on marine terraces along coastal California are interpreted in terms of chemical weathering rates and processes. In regoliths up to 15 m deep and 226 kyrs old, quartz-normalized mass transfer coefficients indicate non-stoichiometric preferential release of Sr > Ca > Na from plagioclase along with lesser amounts of K, Rb and Ba derived from K-feldspar. Smectite weathering results in the loss of Mg and concurrent incorporation of Al and Fe into secondary kaolinite and Fe-oxides in shallow argillic horizons. Elemental losses from weathering of the Santa Cruz terraces fall within the range of those for other marine terraces along the Pacific Coast of North America. Residual amounts of plagioclase and K-feldspar decrease with terrace depth and increasing age. The gradient of the weathering profile bs is defined by the ratio of the weathering rate, R to the velocity at which the profile penetrates into the protolith. A spreadsheet calculator further refines profile geometries, demonstrating that the non-linear regions at low residual feldspar concentrations at shallow depth are dominated by exponential changes in mineral surface-to-volume ratios and at high residual feldspar concentrations, at greater depth, by the approach to thermodynamic saturation. These parameters are of secondary importance to the fluid flux qh, which in thermodynamically saturated pore water, controls the weathering velocity and mineral losses from the profiles. Long-term fluid fluxes required to reproduce the feldspar weathering profiles are in agreement with contemporary values based on solute Cl balances (qh = 0.025-0.17 m yr-1). During saturation-controlled and solute-limited weathering, the greater loss of plagioclase relative to K-feldspar is dependent on the large difference in their respective solubilities instead of the small difference between their respective

  7. Concentration profiles of collagen and proteoglycan in articular cartilage by Fourier transform infrared imaging and principal component regression

    NASA Astrophysics Data System (ADS)

    Yin, Jianhua; Xia, Yang; Lu, Mei

    2012-03-01

    Fourier-transform infrared imaging (FT-IRI) technique with the principal component regression (PCR) method was used to quantitatively determine the 2D images and the depth-dependent concentration profiles of two principal macromolecular components (collagen and proteoglycan) in articular cartilage. Ten 6 μm thick sections of canine humeral cartilage were imaged at a pixel size of 6.25 μm in FT-IRI. The infrared spectra extracted from FT-IRI experiments were imported into a PCR program to calculate the quantitative distributions of both collagen and proteoglycan in dry cartilage, which were subsequently converted into the wet-weight based concentration profiles. The proteoglycan profiles by FT-IRI and PCR significantly correlated in linear regression with the proteoglycan profiles by the non-destructive μMRI (the goodness-of-fit 0.96 and the Pearson coefficient 0.98). Based on these concentration relationships, the concentration images of collagen and proteoglycan in both healthy and lesioned articular cartilage were successfully constructed two dimensionally. The simultaneous construction of both collagen and proteoglycan concentration images demonstrates that this combined imaging and chemometrics approach could be used as a sensitive tool to accurately resolve and visualize the concentration distributions of macromolecules in biological tissues.

  8. Estimation of surface-level PM concentration from satellite observation taking into account the aerosol vertical profiles and hygroscopicity.

    PubMed

    Kim, Kwanchul; Lee, Kwon H; Kim, Ji I; Noh, Youngmin; Shin, Dong H; Shin, Sung K; Lee, Dasom; Kim, Jhoon; Kim, Young J; Song, Chul H

    2016-01-01

    Surface-level PM10 distribution was estimated from the satellite aerosol optical depth (AOD) products, taking the account of vertical profiles and hygroscopicity of aerosols over Jeju, Korea during March 2008 and October 2009. In this study, MODIS AOD data from the Terra and Aqua satellites were corrected with aerosol extinction profiles and relative humidity data. PBLH (Planetary Boundary Layer Height) was determined from MPLNET lidar-derived aerosol extinction coefficient profiles. Through statistical analysis, better agreement in correlation (R = 0.82) between the hourly PM10 concentration and hourly average Sunphotometer AOD was the obtained when vertical fraction method (VFM) considering Haze Layer Height (HLH) and hygroscopic growth factor f(RH) was used. The validity of the derived relationship between satellite AOD and surface PM10 concentration clearly demonstrates that satellite AOD data can be utilized for remote sensing of spatial distribution of regional PM10 concentration. PMID:26421659

  9. Composition of the outermost layer and concentration depth profiles of ammonium nitrate ionic liquid surfaces.

    PubMed

    Ridings, Christiaan; Warr, Gregory G; Andersson, Gunther G

    2012-12-14

    Differences in the surface structure of protic ionic liquids (ILs) with three different cations and a common anion; ethyl-, propyl- and 2-hydroxyethyl- (or ethanol-) ammonium nitrate (EAN, PAN and EtAN, respectively) have been observed by neutral impact collision ion scattering spectroscopy (NICISS) and metastable induced electron spectroscopy/ultraviolet photoelectron spectroscopy (MIES/UPS). NICISS is used to determine the concentration depth profiles of the elements in each IL and it reveals an enrichment of cation alkyl chains of PAN and EtAN in the outermost layer compared to EAN, and a corresponding depletion of nitrate from the outermost layer of the EtAN surface. MIES probes the molecular orbitals of only the species in the outermost layer of a sample and confirms that, while both the anion and the cation are present to some degree at the surface of all three ILs, the cation is enriched to a greater extent at the surface of PAN and EtAN compared to EAN. PMID:23103987

  10. Organic carbon concentration profiles in recent cave sediments: records of agricultural pollution or diagenesis?

    PubMed

    Bottrell, S H

    1996-01-01

    Recent (<7 years old) cave sediments in Speedwell Cavern, Derbyshire, show an approximately exponential decay of organic carbon with depth. This phenomenon was thought to be due to one of two causes: (i) changing agricultural practice within the catchment feeding the cave, especially the increased use of sewage sludge and animal slurry as fertilizer; (ii) a relatively constant organic carbon concentration over time in the input sediment, with subsequent carbon mineralization during diagenesis. Carbon isotope composition of the organic material and the evolution of H/C ratio with depth indicate that the latter hypothesis is correct and that the profiles result from microbial diagenesis, not increased organic carbon inputs. By comparison with sediment of known (7 years) age, temporal decay constants for organic matter can be derived; these lie between rates previously determined for organic matter decomposition in marine sediments and soils. The H/C ratio of organic matter can be modelled as a function of time and proceeds in a similar fashion to soil organic material. PMID:15091425

  11. Nitrogen-concentration control in GaNAs/AlGaAs quantum wells using nitrogen δ-doping technique

    SciTech Connect

    Mano, Takaaki; Jo, Masafumi; Kuroda, Takashi; Noda, Takeshi; Sugimoto, Yoshimasa; Sakuma, Yoshiki; Elborg, Martin; Sakoda, Kazuaki

    2014-05-15

    GaNAs/Al{sub 0.35}Ga{sub 0.65}As multiple quantum wells (MQWs) with nitrogen δ-doping were fabricated on GaAs (100) substrates by plasma-assisted molecular beam epitaxy. High controllability of nitrogen-concentrations in the MQWs was achieved by tuning nitrogen δ-doping time. The maximum nitrogen concentration in the MQWs was 2.8%. The MQWs exhibit intense, narrow photoluminescence emission.

  12. Transcriptional profiling of Al toxicity and tolerance responses in maize roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aluminum (Al) toxicity is a major factor limiting crop yields on acid soils. Plant species exhibit considerable genotypic variation for Al tolerance, which is being exploited by researchers to identify the mechanisms that underlie this trait. In maize, Al tolerance is a complex phenomenon involving ...

  13. Controlling the Al-doping profile and accompanying electrical properties of rutile-phased TiO2 thin films.

    PubMed

    Jeon, Woojin; Rha, Sang Ho; Lee, Woongkyu; Yoo, Yeon Woo; An, Cheol Hyun; Jung, Kwang Hwan; Kim, Seong Keun; Hwang, Cheol Seong

    2014-05-28

    The role of Al dopant in rutile-phased TiO2 films in the evaluation of the mechanism of leakage current reduction in Al-doped TiO2 (ATO) was studied in detail. The leakage current of the ATO film was strongly affected by the Al concentration at the interface between the ATO film and the RuO2 electrode. The conduction band offset of the interface increased with the increase in the Al dopant concentration in the rutile TiO2, which reduced the leakage current in the voltage region pertinent to the next-generation dynamic random access memory application. However, the Al doping in the anatase TiO2 did not notably increase the conduction band offset even with a higher Al concentration. The detailed analyses of the leakage conduction mechanism based on the quantum mechanical transfer-matrix method showed that Schottky emission and Fowler-Nordheim tunneling was the dominant leakage conduction mechanism in the lower and higher voltage regions, respectively. The chemical analyses using X-ray photoelectron spectroscopy corroborated the electrical test results. PMID:24749990

  14. Effect of Ce concentration on luminescence properties of Gd3Ga3Al2O12:Ce nanocrystals

    NASA Astrophysics Data System (ADS)

    Singh, K. V.; Singh, J. P.; Shinde, S.; Singh, A. K.; Tyagi, M.

    2016-05-01

    Gd3Ga3Al2O12 (GGAG) polycrystalline nano-powders doped with different Ce concentrations were prepared by a co-precipitation method followed by heat treatment at 1000°C for 24 h in air and Ar ambient. Structural and morphological studies show that the synthesized powder is pure phase having nanometer (30-50 nm) particle size. Luminescence studies carried out using UV and X-ray excitations revealed a decrease in the luminescence intensity for a Ce concentration greater than 0.5 mol% due to the concentration quenching.

  15. 10Be concentrations and the long-term fate of particle-reactive nuclides in five soil profiles from California

    NASA Astrophysics Data System (ADS)

    Monaghan, M. C.; Krishnaswami, S.; Thomas, J. H.

    1983-10-01

    Concentration-depth profiles of cosmic-ray-produced 10Be ( t1/2 = 1.5m.y.) have been measured by accelerator-mass spectrometry in five soil profiles. These measurements were made in an effort (1) to understand the retentivity of soil surfaces for particle-reactive tracers depositing from the atmosphere on time scales of 10 4-10 6 years, and (2) to explore the application of 10Be as a chronometer of geomorphic surface age. The profiles sampled are from two wave-cut terraces located near Mendocino, California, a table mountain top and an alluvial fan, both located near Friant, California. The ages of the Mendocino terraces are inferred to be (1-5) × 10 5 years based on amino-stratigraphic correlations and models of terrace evolution; those of the table mountain top and alluvial fan are 9.5 × 10 6 years and 6.0 × 10 5 years, respectively, based on K-Ar analyses. All the surfaces sampled are nearly flat and exhibit few erosional features. In addition to 10Be we measured 210Pb, 239,240Pu and 7Be to ascertain the retentivity of the soils for particle-reactive nuclides and to assess the present-day delivery rate of nuclides from the atmosphere. The 7Be inventory is 4.0 dpm/cm 2 similar to those observed at nearby locations. The inventories of 210Pb and Pu isotopes conform to those predicted from model calculations and suggest that the soil surfaces sampled retain the entire burden of particle-reactive nuclides delivered to them over short time scales, ˜ 100 years. The 10Be concentrations in the sample range between (0.2 and 7) × 10 8 atoms/g soil and show strong correlations with leachable Fe and/or Al. The inventory of 10Be in the soil domain sampled is 1-2 orders of magnitude lower than that expected from the geological age of the surface and an average delivery rate of 10Be from the atmosphere, 5.2 × 10 5 atoms/cm 2 yr. The low inventory of 10Be is attributed to its loss from the soil domain sampled by solution transport. Based on a simple ☐-model type

  16. Non-LTE profiles of the Al I autoionization lines. [for solar model atmospheres

    NASA Technical Reports Server (NTRS)

    Finn, G. D.; Jefferies, J. T.

    1974-01-01

    A non-LTE formulation is given for the transfer of radiation in the autoionizing lines of neutral aluminum at 1932 and 1936 A through both the Bilderberg and Harvard-Smithsonian model atmospheres. Numerical solutions for the common source function of these lines and their theoretical line profiles are calculated and compared with the corresponding LTE profiles. The results show that the non-LTE profiles provide a better match with the observations. They also indicate that the continuous opacity of the standard solar models should be increased in this wavelength region if the center-limb variations of observed and theoretical profiles of these lines are to be in reasonable agreement.

  17. Feeding low or pharmacological concentrations of zinc oxide changes the hepatic proteome profiles in weaned piglets.

    PubMed

    Bondzio, Angelika; Pieper, Robert; Gabler, Christoph; Weise, Christoph; Schulze, Petra; Zentek, Juergen; Einspanier, Ralf

    2013-01-01

    Pharmacological levels of zinc oxide can promote growth and health of weaning piglets, but the underlying molecular mechanisms are yet not fully understood. The aim of this study was to determine changes in the global hepatic protein expression in response to dietary zinc oxide in weaned piglets. Nine half-sib piglets were allocated to three dietary zinc treatment groups (50, 150, 2500 mg/kg dry matter). After 14 d, pigs were euthanized and liver samples taken. The increase in hepatic zinc concentration following dietary supplementation of zinc was accompanied by up-regulation of metallothionein mRNA and protein expression. Global hepatic protein profiles were obtained by two-dimensional difference gel electrophoresis following matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. A total of 15 proteins were differentially (P<0.05) expressed between groups receiving control (150 mg/kg) or pharmacological levels of zinc (2500 mg/kg) with 7 down- (e.g. arginase1, thiosulfate sulfurtransferase, HSP70) and 8 up-regulated (e.g. apolipoprotein AI, transferrin, C1-tetrahydrofolate synthase) proteins. Additionally, three proteins were differentially expressed with low zinc supply (50 mg/kg Zn) in comparison to the control diet. The identified proteins were mainly associated with functions related to cellular stress, transport, metabolism, and signal transduction. The differential regulation was evaluated at the mRNA level and a subset of three proteins of different functional groups was selected for confirmation by western blotting. The results of this proteomic study suggest that zinc affects important liver functions such as blood protein secretion, protein metabolism, detoxification and redox homeostasis, thus supporting the hypothesis of intermediary effects of pharmacological levels of zinc oxide fed to pigs. PMID:24282572

  18. Feeding Low or Pharmacological Concentrations of Zinc Oxide Changes the Hepatic Proteome Profiles in Weaned Piglets

    PubMed Central

    Bondzio, Angelika; Pieper, Robert; Gabler, Christoph; Weise, Christoph; Schulze, Petra; Zentek, Juergen; Einspanier, Ralf

    2013-01-01

    Pharmacological levels of zinc oxide can promote growth and health of weaning piglets, but the underlying molecular mechanisms are yet not fully understood. The aim of this study was to determine changes in the global hepatic protein expression in response to dietary zinc oxide in weaned piglets. Nine half-sib piglets were allocated to three dietary zinc treatment groups (50, 150, 2500 mg/kg dry matter). After 14 d, pigs were euthanized and liver samples taken. The increase in hepatic zinc concentration following dietary supplementation of zinc was accompanied by up-regulation of metallothionein mRNA and protein expression. Global hepatic protein profiles were obtained by two-dimensional difference gel electrophoresis following matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. A total of 15 proteins were differentially (P<0.05) expressed between groups receiving control (150 mg/kg) or pharmacological levels of zinc (2500 mg/kg) with 7 down- (e.g. arginase1, thiosulfate sulfurtransferase, HSP70) and 8 up-regulated (e.g. apolipoprotein AI, transferrin, C1-tetrahydrofolate synthase) proteins. Additionally, three proteins were differentially expressed with low zinc supply (50 mg/kg Zn) in comparison to the control diet. The identified proteins were mainly associated with functions related to cellular stress, transport, metabolism, and signal transduction. The differential regulation was evaluated at the mRNA level and a subset of three proteins of different functional groups was selected for confirmation by western blotting. The results of this proteomic study suggest that zinc affects important liver functions such as blood protein secretion, protein metabolism, detoxification and redox homeostasis, thus supporting the hypothesis of intermediary effects of pharmacological levels of zinc oxide fed to pigs. PMID:24282572

  19. ALTIUS, a future small mission for O3 and other atmospheric trace species concentration profiles retrieval

    NASA Astrophysics Data System (ADS)

    Dekemper, Emmanuel; Fussen, Didier; Vanhellemont, Filip; Pieroux, Didier; Mateshvili, Nina; Franssens, Ghislain; Errera, Quentin; Vanhamel, Jurgen; Neefs, Eddy; De Vos, Lieve; Aballea, Ludovic

    2016-04-01

    The ALTIUS (Atmospheric Limb Tracker for the Investigation of the Upcoming Stratosphere) mission aims at the retrieval of atmospheric trace species concentration profiles with a good vertical resolution and a global coverage. It will be flown on a PROBA-type platform on a Sun-synchronous orbit with a 10:00 AM typical local time. The instrument exploits the concept of hyperspectral imaging of different light sources: limb-scattered radiance, Sun, Moon, stars, planets. These sources are observed sequentially, depending on their availability and good positioning. This multi-mode observation capability enables measurements in both bright and dark side of the orbit, extending the coverage to virtually all latitudes and different illumination conditions (including polar night). The instrument concept relies on three independent spectral channels: UV, VIS and NIR. The imaging technique alleviates the need for scanning systems as the field of view will capture the atmosphere from cloud top to the lower thermosphere at once. It also makes the pointing calibration more easy and robust, an important feature knowing that tangent altitude misregistration is one of the major sources of bias in the retrieved products. In each channel, the wavelength selection for each image will be performed by a tunable filter: an AOTF (Acousto-Optical Tunable Filter) for the VIS and NIR, and a FPI (Fabry-Perot Interferometer) in the UV. ALTIUS has recently completed a phase B1 under ESA supervision. The next milestone will be the preliminary design review (PDR) that will take place within a few months from now. Launch is expected for 2020 with a 3-5 years design lifetime. We will present the scientific objectives of the mission, and the current status of the payload and platform concepts. An overview of the main in-flight calibration strategies will be given, and the expected performance of the O3 level-2 product for the different modes of observation will be shown.

  20. A Systematic Approach for Multidimensional, Closed-Form Analytic Modeling: Effective Intrinsic Carrier Concentrations in Ga 1-x Al x As Heterostructures.

    PubMed

    Bennett, Herbert S; Filliben, James J

    2002-01-01

    A critical issue identified in both the technology roadmap from the Optoelectronics Industry Development Association and the roadmaps from the National Electronics Manufacturing Initiative, Inc. is the need for predictive computer simulations of processes, devices, and circuits. The goal of this paper is to respond to this need by representing the extensive amounts of theoretical data for transport properties in the multi-dimensional space of mole fractions of AlAs in Ga1- x Al x As, dopant densities, and carrier densities in terms of closed form analytic expressions. Representing such data in terms of closed-form analytic expressions is a significant challenge that arises in developing computationally efficient simulations of microelectronic and optoelectronic devices. In this paper, we present a methodology to achieve the above goal for a class of numerical data in the bounded two-dimensional space of mole fraction of AlAs and dopant density. We then apply this methodology to obtain closed-form analytic expressions for the effective intrinsic carrier concentrations at 300 K in n-type and p-type Ga1- x Al x As as functions of the mole fraction x of AlAs between 0.0 and 0.3. In these calculations, the donor density N D for n-type material varies between 10(16) cm(-3) and 10(19) cm(-3) and the acceptor density N A for p-type materials varies between 10(16) cm(-3) and 10(20) cm(-3). We find that p-type Ga1- x Al x As presents much greater challenges for obtaining acceptable analytic fits whenever acceptor densities are sufficiently near the Mott transition because of increased scatter in the numerical computer results for solutions to the theoretical equations. The Mott transition region in p-type Ga1- x Al x As is of technological significance for mobile wireless communications systems. This methodology and its associated principles, strategies, regression analyses, and graphics are expected to be applicable to other problems beyond the specific case of effective

  1. Linear energy transfer effects on time profiles of scintillation of Ce-doped LiCaAlF6 crystals

    NASA Astrophysics Data System (ADS)

    Yanagida, Takayuki; Koshimizu, Masanori; Kurashima, Satoshi; Iwamatsu, Kazuhiro; Kimura, Atsushi; Taguchi, Mitsumasa; Fujimoto, Yutaka; Asai, Keisuke

    2015-12-01

    We measured temporal profiles of the scintillation of Ce-doped LiCaAlF6 scintillator crystals at different linear energy transfers (LETs). Based on the comparison of high-LET temporal profiles with those at low LET, a fast component was observed only at low LET. The disappearance of the fast component at high LET is tentatively ascribed to the quenching of excited states at crystal defects owing to the interaction between excited states via the Auger process. In addition, the rise and the initial decay behavior were dependent on the LET. This LET-dependent behavior is explained by an acceleration process and a deceleration process in energy transfer at high LET. The LET-dependent temporal profiles provide the basis for a discrimination technique of gamma-ray and neutron detection events using these scintillators based on the nuclear reaction, 6Li(n,α)t.

  2. Does AL amyloidosis have a unique genomic profile? Gene expression profiling meta-analysis and literature overview.

    PubMed

    Kryukov, Fedor; Kryukova, Elena; Brozova, Lucie; Kufova, Zuzana; Filipova, Jana; Growkova, Katerina; Sevcikova, Tereza; Jarkovsky, Jiri; Hajek, Roman

    2016-10-15

    Immunoglobulin light chain amyloidosis (ALA) is a plasma cell dyscrasia characterized by deposition of amyloid fibrils in various organs and tissues. The current paper is devoted to clarify if ALA has a unique gene expression profile and to its pathogenetic argumentation. The meta-analysis of ALA patients vs. healthy donors, monoclonal gammopathy of undetermined significance, smoldering and multiple myeloma patients' cohorts have revealed molecular signature of ALA consists of 256 genes representing mostly ribosomal proteins and immunoglobulin regions. This signature appears pathogenetically supported and elucidates for the first time the role of ribosome dysfunction in ALA. In summary of our findings with literature overview, we hypothesize that ALA development is associated not only with changes in genes, coding amyloidogenic protein itself, but with post-transcriptional disbalance as well. Based on our data analysis in ALA, ribosome machinery is impaired and the affected link mainly involves translational initiation, elongation and co-translational protein folding. PMID:27288311

  3. Comparative proteomic profiling of cerebrospinal fluid between living and post mortem ALS and control subjects

    PubMed Central

    RANGANATHAN, SRIKANTH; NICHOLL, GEORGINA C.B.; HENRY, SARAH; LUTKA, FRAN; SATHANOORI, RAMASRI; LACOMIS, DAVID; BOWSER, ROBERT

    2010-01-01

    Neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), lack definitive diagnostic tests or biomarkers of disease progression. Most studies that investigate protein abnormalities in ALS have used biofluids such as blood or cerebrospinal fluid (CSF), while some have used post mortem tissue or CSF samples. Since ALS disease progression and post mortem effects probably induce significant alterations to protein modifications or proteolysis, we directly examined the CSF proteome from ALS subjects at various lengths of time from symptom onset and at autopsy by mass spectrometry based proteomics. CSF was also obtained from both healthy age-matched control subjects and at autopsy from healthy and Alzheimer's disease (AD) controls. We identified significant differences in the CSF proteome between living and post mortem ALS subjects, as well as living and post mortem control subjects. We also noted differences in the CSF proteome of ALS subjects that have exhibited symptoms for varying lengths of time and between ALS and AD subjects at end-stage of disease. This is the first study describing differences in the CSF proteome from post mortem and living ALS subjects using a mass spectrometric approach. These differences highlight the importance of utilizing CSF from living ALS subjects near the time of symptom onset for the identification of early protein biomarkers, although some protein alterations that occur early in the disease process are maintained throughout the course of disease and in post mortem samples. PMID:17852009

  4. Particle concentration and tube size dependence of viscosities of Al2O3-water nanofluids flowing through micro- and minitubes

    NASA Astrophysics Data System (ADS)

    Jang, Seok Pil; Lee, Ji-Hwan; Hwang, Kyo Sik; Choi, Stephen U. S.

    2007-12-01

    An experimental and theoretical investigation has been performed on the effective viscosity of Al2O3-water nanofluids flowing through micrometer- and millimeter-sized circular tubes in the fully developed laminar flow regime. We have discovered that the effective viscosity of Al2O3-water nanofluids increases nonlinearly with the volume concentration of nanoparticles even in the very low range of 0.02-0.3vol% and strongly depends on the ratio of the nanoparticle diameter to the tube diameter. We have developed a modified Einstein model that accounts for the slip mechanism in nanofluids. The new model captures these new rheological features of nanofluids.

  5. Kinks in experimental diffusion profiles of a dissolving semi-crystalline polymer explained by a concentration-dependent diffusion coefficient.

    PubMed

    Hermes, Helen E; Sitta, Christoph E; Schillinger, Burkhard; Löwen, Hartmut; Egelhaaf, Stefan U

    2015-06-28

    The dissolution of polyethylene oxide (PEO) tablets in water has been followed in situ by neutron radiography. When in contact with water, the crystalline phase of semi-crystalline PEO melts once a certain water content is attained. Polymer concentration profiles obtained from the neutron transmission images exhibited a pronounced kink which corresponds to a sharp front in the images and which is related to the melting transition. Sharp diffusion fronts and phase transitions are often linked to non-Fickian behaviour. However, by considering the time evolution of the complete concentration profiles in detail it is shown that the dissolution process can be explained using Fickian diffusion equations with a concentration-dependent diffusion coefficient. PMID:26018995

  6. How do esters and dimethyl sulphide concentrations affect fruity aroma perception of red wine? Demonstration by dynamic sensory profile evaluation.

    PubMed

    Lytra, Georgia; Tempere, Sophie; Marchand, Stéphanie; de Revel, Gilles; Barbe, Jean-Christophe

    2016-03-01

    Our study focused on variations in wine aroma perception and molecular composition during tasting over a period of 30min. In parallel, dynamic analytical and sensory methods were applied to study changes in the wines' molecular and aromatic evolution. Dynamic sensory profile evaluations clearly confirmed the evolution of the wine's fruity notes during sensory analysis, highlighting significant differences for red-berry and fresh fruit as well as black berry and jammy fruit, after 5 and 15min, respectively. Dynamic analytical methods revealed a decrease in ester and dimethyl sulphide (DMS) concentrations in the first few minutes. Sensory profiles of aromatic reconstitutions demonstrated that the aromatic modulation of fruity notes observed during wine tasting was explained by changes in ester and DMS concentrations. These results revealed that variations in concentrations of DMS and esters during wine tasting had a qualitative impact, by modulating fruity aromas in red wine. PMID:26471544

  7. Dissolved methane concentration profiles and air-sea fluxes from 41°S to 27°N

    NASA Astrophysics Data System (ADS)

    Kelley, Cheryl A.; Jeffrey, Wade H.

    2002-07-01

    Water column samples from a transect cruise from southern Chile through the Panama Canal to the Gulf of Mexico were used to determine dissolved methane depth profiles and air-sea methane fluxes. In the Gulf of Mexico, surface concentrations were approximately 40% supersaturated with respect to the atmosphere, whereas near the equator and in the Peru upwelling region, 10-20% supersaturation generally occurred. These saturation ratios translate into an average flux of methane from the sea surface to the atmosphere of 0.38 μmol m-2 d-1. In addition, water column profiles of dissolved methane indicate that subsurface maxima in dissolved methane concentrations are a consistent feature of the open ocean, except near the equator. At the equator, the subsurface peak at the base of the mixed layer may be bowed down by the Equatorial Undercurrent. The highest methane concentration (12 nM) was observed in the Peru upwelling region.

  8. Effect of milling time and CNT concentration on hardness of CNT/Al{sub 2024} composites produced by mechanical alloying

    SciTech Connect

    Perez-Bustamante, R.; Perez-Bustamante, F.; Estrada-Guel, I.; Licea-Jimenez, L.; Miki-Yoshida, M.; Martinez-Sanchez, R.

    2013-01-15

    Carbon nanotube/2024 aluminum alloy (CNT/Al{sub 2024}) composites were fabricated with a combination of mechanical alloying (MA) and powder metallurgy routes. Composites were microstructurally and mechanically evaluated at sintering condition. A homogeneous dispersion of CNTs in the Al matrix was observed by a field emission scanning electron microscopy. High-resolution transmission electron microscopy confirmed not only the presence of well dispersed CNTs but also needle-like shape aluminum carbide (Al{sub 4}C{sub 3}) crystals in the Al matrix. The formation of Al{sub 4}C{sub 3} was suggested as the interaction between the outer shells of CNTs and the Al matrix during MA process in which crystallization took place after the sintering process. The mechanical behavior of composites was evaluated by Vickers microhardness measurements indicating a significant improvement in hardness as function of the CNT content. This improvement was associated to a homogeneous dispersion of CNTs and the presence of Al{sub 4}C{sub 3} in the aluminum alloy matrix. - Highlights: Black-Right-Pointing-Pointer The 2024 aluminum alloy was reinforced by CNTs by mechanical alloying process. Black-Right-Pointing-Pointer Composites were microstructural and mechanically evaluated after sintering condition. Black-Right-Pointing-Pointer The greater the CNT concentration, the greater the hardness of the composites. Black-Right-Pointing-Pointer Higher hardness in composites is achieved at 20 h of milling. Black-Right-Pointing-Pointer The formation of Al{sub 4}C{sub 3} does not present a direct relationship with the milling time.

  9. A simple method of obtaining concentration depth-profiles from X-ray diffraction

    NASA Technical Reports Server (NTRS)

    Wiedemann, K. E.; Unnam, J.

    1984-01-01

    The construction of composition profiles from X-ray intensity bands was investigated. The intensity band-to-composition profile transformation utilizes a solution which can be easily evaluated. The technique can be applied to thin films and thick speciments for which the variation of lattice parameters, linear absorption coefficient, and reflectivity with composition are known. A deconvolution scheme with corrections for the instrumental broadening and ak-alfadoublet is discussed.

  10. Investigation of Al doping concentration effect on the structural and optical properties of the nanostructured CdO thin film

    NASA Astrophysics Data System (ADS)

    Gencer Imer, Arife

    2016-04-01

    Nanostructured aluminium (Al) doped cadmium oxide (CdO) films with highly electrical conductivity and optical transparency have been deposited for the first time on soda-lime glass substrates preheated at 250 °C by ultrasonic spray coating technique. The aluminium dopant content in the CdO film was changed from 0 to 5 at%. The influencing of Al doping on the structural, morphological, electrical and optical properties of the CdO nanostructured films has been investigated. Atomic force microscopy study showed the grain size of the films is an order of nanometers, and it decreases with increase in Al dopant content. All the films having cubic structure with a lattice parameter 4.69 Å were determined via X ray diffraction analysis. The optical band gap value of the films, obtained by optical absorption, was found to increase with Al doping. Electrical studies exhibited mobility, carrier concentration and resistivity of the film strongly dependent on the doping content. It has been evaluated that optical band gap, and grain size of the nanostructured CdO film could be modified by Al doping.

  11. Liquid chromatographic profiles of major carotenoid esters in commercially processed California Navel and Valencia orange juice concentrates.

    PubMed

    Philip, T; Chen, T S; Nelson, D B

    1988-06-17

    A procedure for establishing profiles of major carotenoid esters in commercially processed Valencia and Navel orange juice concentrates by reversed-phase liquid chromatography (LC) using Sudan 1 as internal standard is described. The procedure involved conversion of 5,6-epoxides in heat concentrated citrus juices to more stable 5,8-epoxides by treatment of extracted carotenoids with hydrochloric acid followed by dual wavelength analyses at 400 and 465 nm using LC. The esters of 5,8-furanoids (auroxanthin and mutatoxanthin) were approximately quantitated at 400 nm without interference from other carotenoids. Cryptoxanthin esters and free cryptoxanthin, lutein esters, citraurin esters and carotenes were approximately quantitated at 465 nm without interference from auroxanthin esters. The furanoid esters varied from 60 to 75% of the total carotenoids in the concentrates. The cryptoxanthin esters varied from 5 to 10% of the total carotenoids in Valencia orange juice concentrates and from 10 to 15% of the total carotenoids in Navel orange juice concentrates. Citraurin esters were present only in Navel orange juice concentrates and beta-carotene content was less than 5% of the total carotenoids in both concentrates. The total carotenoids and individual carotenoids increased with the advance in season in Navel orange juice concentrates which had less than half the amount of total carotenoids of Valencia orange juice concentrates. PMID:3417817

  12. Effects of Solute Concentrations on Kinetic Pathways in Ni-Al-Cr Alloys

    NASA Technical Reports Server (NTRS)

    Booth-Morrison, Christopher; Weninger, Jessica; Sudbrack, Chantal K.; Mao, Zugang; Seidman, David N.; Noebe, Ronald D.

    2008-01-01

    The kinetic pathways resulting from the formation of coherent gamma'-precipitates from the gamma-matrix are studied for two Ni-Al-Cr alloys with similar gamma'-precipitate volume fractions at 873 K. The details of the phase decompositions of Ni-7.5Al-8.5Cr at.% and Ni-5.2Al-14.2Cr at.% for aging times from 1/6 to 1024 h are investigated by atom-probe tomography, and are found to differ significantly from a mean-field description of coarsening. The morphologies of the gamma'-precipitates of the alloys are similar, though the degrees of gamma'-precipitate coagulation and coalescence differ. Quantification within the framework of classical nucleation theory reveals that differences in the chemical driving forces for phase decomposition result in differences in the nucleation behavior of the two alloys. The temporal evolution of the gamma'-precipitate average radii and the gamma-matrix supersaturations follow the predictions of classical coarsening models. The compositional trajectories of the gamma-matrix phases of the alloys are found to follow approximately the equilibrium tie-lines, while the trajectories of the gamma'-precipitates do not, resulting in significant differences in the partitioning ratios of the solute elements.

  13. A method of rapidly obtaining concentration-depth profiles from X-ray diffraction

    NASA Technical Reports Server (NTRS)

    Wiedemann, K. E.; Unnam, J.

    1985-01-01

    A broadened diffraction peak, or intensity band, is observed in the case diffraction from a nonhomogeneous phase in which the variations in compositions result in a range of lattice spacings. An intriguing aspect regarding the relationship between the X-ray diffraction band and the composition-depth profile is the hypersensitivity of the intensity band to the shape of the profile. A number of investigators have sought to use this sensitivity to construct high-precision profiles. Difficulties encountered are related to complications due to intensity broadening, and prohibitive computational requirements. Simulation techniques have provided the most accurate interpretation of the intensity band. However, the involved calculations have been prohibitively long. The present study discusses a technique which has simple computational requirements and is as accurate and flexible as the simulation techniques.

  14. Simulation of the effective concentration profiles in InGaAs/GaAs heterostructures containing δ-doped layers

    SciTech Connect

    Khazanova, S. V. Degtyarev, V. E.; Tikhov, S. V.; Baidus, N. V.

    2015-01-15

    InGaAs/GaAs heterostructures containing quantum wells and δ-doped layers are studied theoretically and experimentally. On the basis of the procedure of self-consistently solving the Schrödinger equation and Poisson equation, the differential capacitance and the apparent electron concentration profiles are numerically calculated for structures with different mutual arrangements of the quantum well and the δ layer. The results of the calculations are compared with the result of analyzing the experimental capacitance-voltage characteristics of the structures. The systematic features of the behavior of the apparent concentration profiles and capacitance-voltage characteristics in relation to the geometric properties of the structure, the temperature, and the doping level are established.

  15. Polychlorinated dibenzo-p-dioxin and dibenzofuran concentration profiles in sediment and fish tissue of the Willamette Basin, Oregon

    USGS Publications Warehouse

    Bonn, B.A.

    1998-01-01

    Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) are highly hydrophobic compounds that have been implicated as carcinogens and, more recently, as estrogen disrupters. An occurrence and distribution study of these compounds in the Willamette Basin, Oregon, was conducted by the U.S. Geological Survey as part of the National Water-Quality Assessment Program. Bed sediment was collected from 22 sites; fish tissue was collected from eight sites. PCDD/F were found to be ubiquitous in Willamette Basin sediment. A distinct homolog profile, dominated by octachlorodibenzo-p-dioxin, was observed in sediment throughout the basin. The PCDD homolog profile was consistent at all sites, regardless of total PCDD/F concentration, presence of point sources, subbasin size, geographic location or land use. Principal components analysis revealed a gradient among the homolog profiles that showed increasing dominance of highly chlorinated congeners where human and industrial activity increased. Tissue and bed sediment obtained from the same site did not have similar PCDD/F concentrations or homolog profiles. Fish tissue showed enrichment in less chlorinated congeners and congeners with chlorine substitutions in the 2, 3, 7 and 8 positions.

  16. Average pollutant concentration in soil profile simulated with Convective-Dispersive Equation. Model and Manual

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Different parts of soil solution move with different velocities, and therefore chemicals are leached gradually from soil with infiltrating water. Solute dispersivity is the soil parameter characterizing this phenomenon. To characterize the dispersivity of soil profile at field scale, it is desirable...

  17. In situ TDLAS measurement of absolute acetylene concentration profiles in a non-premixed laminar counter-flow flame

    NASA Astrophysics Data System (ADS)

    Wagner, S.; Klein, M.; Kathrotia, T.; Riedel, U.; Kissel, T.; Dreizler, A.; Ebert, V.

    2012-06-01

    Acetylene (C2H2), as an important precursor for chemiluminescence species, is a key to understand, simulate and model the chemiluminescence and the related reaction paths. Hence we developed a high resolution spectrometer based on direct Tunable Diode Laser Absorption Spectroscopy (TDLAS) allowing the first quantitative, calibration-free and spatially resolved in situ C2H2 measurement in an atmospheric non-premixed counter-flow flame supported on a Tsuji burner. A fiber-coupled distributed feedback diode laser near 1535 nm was used to measure several absolute C2H2 concentration profiles (peak concentrations up to 9700 ppm) in a laminar non-premixed CH4/air flame ( T up to 1950 K) supported on a modified Tsuji counter-flow burner with N2 purge slots to minimize end flames. We achieve a fractional optical resolution of up to 5×10-5 OD (1 σ) in the flame, resulting in temperature-dependent acetylene detection limits for the P17e line at 6513 cm-1 of up to 2.1 ppmṡm. Absolute C2H2 concentration profiles were obtained by translating the burner through the laser beam using a DC motor with 100 μm step widths. Intercomparisons of the experimental C2H2 profiles with simulations using our new hydrocarbon oxidation mechanisms show excellent agreement in position, shape and in the absolute C2H2 values.

  18. High hole concentration in p-type AlGaN by indium-surfactant-assisted Mg-delta doping

    SciTech Connect

    Chen, Yingda; Wu, Hualong; Han, Enze; Yue, Guanglong; Chen, Zimin; Wu, Zhisheng; Wang, Gang; Jiang, Hao

    2015-04-20

    High hole concentration was achieved in Mg-doped Al{sub x}Ga{sub 1−x}N (x ∼ 0.4) by using indium-surfactant-assisted delta doping method. A maximum carrier concentration of 4.75 × 10{sup 18 }cm{sup −3} was obtained, which is three times higher than that of the conventionally delta-doped sample. Sheet resistivity as low as 2.46 × 10{sup 4} Ω/sq was realized, benefiting from the high hole concentration (p). Analysis results show that the Mg incorporation is effectively enhanced, while the compensation ratio and acceptor activation energy (E{sub A}) are significantly reduced by using In surfactant. It was also found that the In surfactant may induce stronger valence-band modulation, contributing to the decrease of E{sub A} and the increase of p.

  19. Synthesis of DNL-6 with a high concentration of Si (4 Al) environments and its application in CO(2) separation.

    PubMed

    Su, Xiong; Tian, Peng; Fan, Dong; Xia, Qinghua; Yang, Yue; Xu, Shutao; Zhang, Lin; Zhang, Ying; Wang, Dehua; Liu, Zhongmin

    2013-05-01

    The synthesis of DNL-6 with a high concentration of Si (4 Al) environments [Si/(Si+Al+P)=0.182 mol, denoted as M-DNL-6] is demonstrated. This represents the highest reported concentration of such environments in silicoaluminophosphate (SAPO) molecular sieves. Adsorption studies show that the high Si (4 Al) content in M-DNL-6, with an increased number of Brønsted acid sites in the framework, greatly promotes the adsorption of CO(2). M-DNL-6 exhibits a large CO(2) uptake capacity of up to 6.18 mmol g(-1) at 273 K and 101 kPa, and demonstrates high ratios of CO(2)/CH(4) and CO(2)/N(2) separation. From breakthrough and cycling experiments, M-DNL-6 demonstrates the ability to completely separate CO(2) from CH(4) or N(2) with a dynamic capacity of approximately 8.0 wt % before breakthrough. Importantly, the adsorbed CO(2) is easily released from the adsorbent through a simple gas purging operation at room temperature to regain 95 % of the original adsorption capacity. These results suggest that M-DNL-6 can be used as a potential adsorbent for CO(2) capture in pressure swing adsorption processes. PMID:23606439

  20. Measured and modelled concentrations and vertical profiles of airborne particulate matter within the boundary layer of a street canyon.

    PubMed

    Colls, J J; Micallef, A

    1999-09-01

    Concentrations and vertical profiles of various fractions of airborne particulate matter (suspended particulate matter (SPM), PM10 and PM2.5) have been measured over the first three metres from ground in a street canyon. Measurements were carried out using automated near real-time apparatus called the Kinetic Sequential Sampling (KSS) system. KSS system is essentially an electronically-controlled lift carrying a real-time particle monitor for sampling air sequentially, at different heights within the breathing zone, which includes all heights within the surface layer of a street canyon at which people may breathe. Data is automatically logged at the different receptor levels, for the determination of the average vertical concentration profile of airborne particulate matter. For measuring the airborne particle concentration, a Grimm Dust Monitor 1.104/5 was used. The recorded data also allows for time series analysis of airborne particulate matter concentration at different heights. Time series data and hourly-average vertical concentration profiles in the boundary layer of the confines of a street are thought to be mainly determined by traffic emissions and traffic associated processes. Hence the measured data were compared with results of a street canyon emission-dispersion model in time and space. This Street Level Air Quality (SLAQ) model employs the plume-box technique and includes modules for simulating vehicle-generated effects such as thermally- and mechanically-generated turbulence and resuspension of road dust. Environmental processes, such as turbulence resulting from surface sensible heat and the formation of sulphate aerosol from sulphur dioxide exhaust emissions, are taken into account. The paper presents an outline description of the measuring technique and model used, and a comparison of the measured and modelled data. PMID:10535122

  1. Profiles.

    ERIC Educational Resources Information Center

    School Arts, 1979

    1979-01-01

    Profiles seven Black, Native American, and Chicano artists and art teachers: Hale A. Woodruff, Allan Houser, Luis Jimenez, Betrand D. Phillips, James E. Pate, I, and Fernando Navarro. This article is part of a theme issue on multicultural art. (SJL)

  2. Direct Detection 1.6?m DIAL / Doppler Lidar for Measurements of CO2 Concentration and Wind Profiles (Invited)

    NASA Astrophysics Data System (ADS)

    Shibata, Y.; Nagasawa, C.; Abo, M.

    2013-12-01

    Knowledge of present carbon sources and sinks including their spatial distribution and their variation in time is one of the essential information for predicting future CO2 atmospheric concentration levels. Moreover, wind information is an important parameter for transport simulations and inverse estimation of surface CO2 flux. The differential absorption lidar (DIAL) and the Doppler wind lidar with the range resolution is expected to measure atmospheric CO2 profiles and wind profiles in the atmospheric boundary layer and lower troposphere from a ground platform. We have succeeded to develop a scanning 1.6 μm DIAL and incoherent Doppler lidar system for simultaneously measuring CO2 concentration and wind speed profiles. Our 1.6 μm DIAL system consists of the Optical Parametric Generator (OPG) transmitter that excited by the LD pumped Nd: YAG laser with high repetition rate (500 Hz) and the receiving optics that included the near-infrared photomultiplier tube with high quantum efficiency operating at the photon counting mode, a fiber Bragg grating (FBG) filter to detect a Doppler shift, and a 25 cm telescope [1] [2]. We had developed an optical parametric oscillator (OPO) system for 1.6 μm CO2 DIAL[3]. To achieve continuous tuning of the resonant OPO output without mode hopping, it is necessary to vary the OPO cavity length synchronously with the seed-frequency. On the other hand, the OPG does not require a cavity and instead rely on sufficient conversion efficiency to be obtained with a single pass through the crystal. The single-frequency oscillation of the OPG was achieved by injection seeding. The CO2-DIAL was operated with the range-height indicator (RHI) mode, and the 2-D measurement provided inhomogeneity in the boundary layer. Vertical CO2 concentration profiles and wind profiles were also measured simultaneously. The elevation angle was fixed at 52 deg and CO2 concentration profiles were obtained up to 1 km altitude with 200 m height resolution. Vertical

  3. Profiling Speech and Pausing in Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD)

    PubMed Central

    Yunusova, Yana; Graham, Naida L.; Shellikeri, Sanjana; Phuong, Kent; Kulkarni, Madhura; Rochon, Elizabeth; Tang-Wai, David F.; Chow, Tiffany W.; Black, Sandra E.; Zinman, Lorne H.; Green, Jordan R.

    2016-01-01

    Objective This study examines reading aloud in patients with amyotrophic lateral sclerosis (ALS) and those with frontotemporal dementia (FTD) in order to determine whether differences in patterns of speaking and pausing exist between patients with primary motor vs. primary cognitive-linguistic deficits, and in contrast to healthy controls. Design 136 participants were included in the study: 33 controls, 85 patients with ALS, and 18 patients with either the behavioural variant of FTD (FTD-BV) or progressive nonfluent aphasia (FTD-PNFA). Participants with ALS were further divided into 4 non-overlapping subgroups—mild, respiratory, bulbar (with oral-motor deficit) and bulbar-respiratory—based on the presence and severity of motor bulbar or respiratory signs. All participants read a passage aloud. Custom-made software was used to perform speech and pause analyses, and this provided measures of speaking and articulatory rates, duration of speech, and number and duration of pauses. These measures were statistically compared in different subgroups of patients. Results The results revealed clear differences between patient groups and healthy controls on the passage reading task. A speech-based motor function measure (i.e., articulatory rate) was able to distinguish patients with bulbar ALS or FTD-PNFA from those with respiratory ALS or FTD-BV. Distinguishing the disordered groups proved challenging based on the pausing measures. Conclusions and Relevance This study demonstrated the use of speech measures in the identification of those with an oral-motor deficit, and showed the usefulness of performing a relatively simple reading test to assess speech versus pause behaviors across the ALS—FTD disease continuum. The findings also suggest that motor speech assessment should be performed as part of the diagnostic workup for patients with FTD. PMID:26789001

  4. Transcriptome Profiling Following Neuronal and Glial Expression of ALS-Linked SOD1 in Drosophila

    PubMed Central

    Kumimoto, Emily L.; Fore, Taylor R.; Zhang, Bing

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) generally is a late-onset neurodegenerative disease. Mutations in the Cu/Zn superoxide dismutase 1 (SOD1) gene account for approximately 20% of familial ALS and 2% of all ALS cases. Although a number of hypotheses have been proposed to explain mutant SOD1 toxicity, the molecular mechanisms of the disease remain unclear. SOD1-linked ALS is thought to function in a non–cell-autonomous manner such that motoneurons are critical for the onset, and glia contribute to progression of the disease. Recently, it has been shown in Drosophila melanogaster that expression of human SOD1 in a subset of neuronal cells causes synaptic transmission defects, modified motor function, and altered sensitivity to compounds that induce oxidative stress. Here we used the Gal4-UAS (Upstream Activation Sequence) system to further characterize flies expressing wild-type Drosophila SOD1 (dSOD1) and the mutant human SOD1G85R (G85R) allele in motoneurons and glia. Cell-specific expression of both dSOD1 and G85R was found to influence lifespan, affect sensitivity to hydrogen peroxide, and alter lipid peroxidation levels. To better understand the genetic consequences of G85R expression in motoneurons and glia, we conducted microarray analysis of both young flies (5 days old) and old flies (45 days old) expressing G85R selectively in motoneurons or glia and concurrently in motoneurons and glia. Results from this microarray experiment identified candidate genes for further investigation and may help elucidate the individual and combined contributions of motoneurons and glia in ALS. PMID:23550139

  5. Estimating suspended solids concentrations from backscatter intensity measured by acoustic Doppler current profiler in San Francisco Bay, California

    USGS Publications Warehouse

    Gartner, J.W.

    2004-01-01

    The estimation of mass concentration of suspended solids is one of the properties needed to understand the characteristics of sediment transport in bays and estuaries. However, useful measurements or estimates of this property are often problematic when employing the usual methods of determination from collected water samples or optical sensors. Analysis of water samples tends to undersample the highly variable character of suspended solids, and optical sensors often become useless from biological fouling in highly productive regions. Acoustic sensors, such as acoustic Doppler current profilers that are now routinely used to measure water velocity, have been shown to hold promise as a means of quantitatively estimating suspended solids from acoustic backscatter intensity, a parameter used in velocity measurement. To further evaluate application of this technique using commercially available instruments, profiles of suspended solids concentrations are estimated from acoustic backscatter intensity recorded by 1200- and 2400-kHz broadband acoustic Doppler current profilers located at two sites in San Francisco Bay, California. ADCP backscatter intensity is calibrated using optical backscatterance data from an instrument located at a depth close to the ADCP transducers. In addition to losses from spherical spreading and water absorption, calculations of acoustic transmission losses account for attenuation from suspended sediment and correction for nonspherical spreading in the near field of the acoustic transducer. Acoustic estimates of suspended solids consisting of cohesive and noncohesive sediments are found to agree within about 8-10% (of the total range of concentration) to those values estimated by a second optical backscatterance sensor located at a depth further from the ADCP transducers. The success of this approach using commercially available Doppler profilers provides promise that this technique might be appropriate and useful under certain conditions in

  6. Effects of age, adipose percent, and reproduction on PCB concentrations and profiles in an extreme fasting North Pacific marine mammal.

    PubMed

    Peterson, Sarah H; Hassrick, Jason L; Lafontaine, Anne; Thomé, Jean-Pierre; Crocker, Daniel E; Debier, Cathy; Costa, Daniel P

    2014-01-01

    Persistent organic pollutants, including polychlorinated biphenyls (PCBs), are widely distributed and detectable far from anthropogenic sources. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometers to forage in coastal and open-ocean regions of the northeast Pacific Ocean and then return to land where they fast while breeding and molting. Our study examined potential effects of age, adipose percent, and the difference between the breeding and molting fasts on PCB concentrations and congener profiles in blubber and serum of northern elephant seal females. Between 2005 and 2007, we sampled blubber and blood from 58 seals before and after a foraging trip, which were then analyzed for PCBs. Age did not significantly affect total PCB concentrations; however, the proportion of PCB congeners with different numbers of chlorine atoms was significantly affected by age, especially in the outer blubber. Younger adult females had a significantly greater proportion of low-chlorinated PCBs (tri-, tetra-, and penta-CBs) than older females, with the opposite trend observed for hepta-CBs, indicating that an age-associated process such as parity (birth) may significantly affect congener profiles. The percent of adipose tissue had a significant relationship with inner blubber PCB concentrations, with the highest mean concentrations observed at the end of the molting fast. These results highlight the importance of sampling across the entire blubber layer when assessing contaminant levels in phocid seals and taking into account the adipose stores and reproductive status of an animal when conducting contaminant research. PMID:24755635

  7. Effects of Age, Adipose Percent, and Reproduction on PCB Concentrations and Profiles in an Extreme Fasting North Pacific Marine Mammal

    PubMed Central

    Peterson, Sarah H.; Hassrick, Jason L.; Lafontaine, Anne; Thomé, Jean-Pierre; Crocker, Daniel E.; Debier, Cathy; Costa, Daniel P.

    2014-01-01

    Persistent organic pollutants, including polychlorinated biphenyls (PCBs), are widely distributed and detectable far from anthropogenic sources. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometers to forage in coastal and open-ocean regions of the northeast Pacific Ocean and then return to land where they fast while breeding and molting. Our study examined potential effects of age, adipose percent, and the difference between the breeding and molting fasts on PCB concentrations and congener profiles in blubber and serum of northern elephant seal females. Between 2005 and 2007, we sampled blubber and blood from 58 seals before and after a foraging trip, which were then analyzed for PCBs. Age did not significantly affect total PCB concentrations; however, the proportion of PCB congeners with different numbers of chlorine atoms was significantly affected by age, especially in the outer blubber. Younger adult females had a significantly greater proportion of low-chlorinated PCBs (tri-, tetra-, and penta-CBs) than older females, with the opposite trend observed for hepta-CBs, indicating that an age-associated process such as parity (birth) may significantly affect congener profiles. The percent of adipose tissue had a significant relationship with inner blubber PCB concentrations, with the highest mean concentrations observed at the end of the molting fast. These results highlight the importance of sampling across the entire blubber layer when assessing contaminant levels in phocid seals and taking into account the adipose stores and reproductive status of an animal when conducting contaminant research. PMID:24755635

  8. Influence of pH and TOC concentration on Cu, Zn, Cd, and Al speciation in rivers.

    PubMed

    Gundersen, Pål; Steinnes, Eiliv

    2003-01-01

    Dissolved ( < approximately 4 nm, dialysis in situ), colloidal ( < 0.45 microm filtered, minus dissolved) and particulate (total, minus < 0.45 microm filtered) concentrations of Cu, Zn, Cd, (Al) in eight (three) mining polluted rivers were determined by atomic absorption spectrometry (flame and graphite furnace). The metal size distribution in the rivers was compared to pH, Ca concentration, alkalinity, conductivity, and total organic carbon (TOC). Data plots based on the present and other studies also yielded information about the interrelations between TOC, pH and metal adsorption in rivers and lakes. Less than 10% of Cu, Zn, and Cd were sorbed on particles or colloids in two rivers with average pH at 3.1 and 5.1, whereas 46%, 21%, and 21% of Cu, Zn, and Cd, respectively, occurred in sorbed form in six pH neutral rivers. In three pH neutral rivers, on average 55% of Al was in colloidal form, whereas the dissolved and particulate fractions were 21% and 23%, respectively. Our data combined with data from similar studies support conclusions from other research suggesting that the percent fraction of metals adsorbed on particles rises steeply from almost zero to nearly 100% within a narrow and element specific pH range. Changes in TOC concentration seem capable of shifting the pH to % metal absorption curves in the order of one pH unit. PMID:12502060

  9. Bias in determining aluminum concentrations: Comparison of digestion methods and implications on Al management.

    PubMed

    He, Y Thomas; Ziemkiewicz, Paul F

    2016-09-01

    Aluminum is an important aquatic contaminant due to its ubiquity, toxicity and low regulatory discharge limits. Aluminum is mobilized in mining related, acidic drainage and is commonly a regulated pollutant. However, while aquatic toxicity studies and toxicity criteria are based on dissolved aluminum(Ald), discharge levels are, for statutory reasons, based on total recoverable aluminum (Alt). The rationale for using total recoverable aluminum recognizes the potential for the release of exchangeable, toxic cations or dissolution of metastable metal flocs in the event the discharge enters an acidic receiving stream. The digestion methods used in determining total recoverable metals are not meant to dissolve aluminosilicate clay particles but we found that they do, resulting in positively biased total recoverable aluminum values. This study explored the interaction between total suspended solids (TSS) and total recoverable aluminum using three digestion methods to evaluate which method introduced the least bias. Using field collected water and sediment samples from two coal mine drainage sites in Central West Virginia, three total recoverable digestion methods (USEPA Method 200.7, M1; USGS In-Bottle method, M2; and a Modified In-Bottle method, M3) were used to determine total recoverable aluminum across a range of total suspended solids concentrations. Baseline simulation experiments were conducted at pH 2.5, 3.5, 4.5 and 5.5 at different total suspended solids concentrations. Results indicated that dissolved aluminum did not respond to increasing total suspended solids concentrations while determined total recoverable aluminum increased with total suspended solids, indicating varying degrees of clay dissolution and, thus bias in the total recoverable aluminum concentration. While all three digestion methods overestimated total recoverable aluminum, at the same total suspended solids concentration, total recoverable aluminum extracted by USEPA Method 200.7 (M1) was

  10. Composition profiling of GaAs/AlGaAs quantum dots grown by droplet epitaxy

    SciTech Connect

    Bocquel, J.; Koenraad, P. M.; Giddings, A. D.; Prosa, T. J.; Larson, D. J.; Mano, T.

    2014-10-13

    Droplet epitaxy (DE) is a growth method which can create III-V quantum dots (QDs) whose optoelectronic properties can be accurately controlled through the crystallisation conditions. In this work, GaAs/AlGaAs DE-QDs have been analyzed with the complimentary techniques of cross-sectional scanning tunneling microscopy and atom probe tomography. Structural details and a quantitative chemical analysis of QDs of different sizes are obtained. Most QDs were found to be pure GaAs, while a small proportion exhibited high intermixing caused by a local etching process. Large QDs with a high aspect ratio were observed to have an Al-rich crown above the GaAs QD. This structure is attributed to differences in mobility of the cations during the capping phase of the DE growth.

  11. Soil air carbon dioxide and nitrous oxide concentrations in profiles under tallgrass prairie and cultivation

    SciTech Connect

    Sotomayor, D.; Rice, C.W.

    1999-05-01

    Assessing the dynamics of gaseous production in soils is of interest because they are important sources and sinks of greenhouse gases. Changes in soil air carbon dioxide (CO{sub 2}) and nitrous oxide (N{sub 2}O) concentrations were studied in a Reading silt loam under prairie and cultivation. Concentrations were measured in situ over a 17-mo period to a depth of 3 m. Multilevel samples permitted collection of gases with subsequent measurement by gas chromatography in the laboratory. Soil air N{sub 2}O concentrations were near atmospheric levels for a majority of the study period in the prairie site but were significantly higher in the cultivated site. Annual mean N{sub 2}O concentrations were 0.403 and 1.09 {micro}L L{sup {minus}1} in the prairie and cultivated sites, respectively. Soil air CO{sub 2} annual mean concentrations were 1.56 {times} 10{sup 4} and 1.10 {times} 10{sup 4} {micro}L L{sup {minus}1} and ranged from 0.096 {times} 10{sup 4} to 6.45 {times} 10{sup 4} {micro}L L{sup {minus}1} and 0.087 {times} 10{sup 4} to 3.59 {times} 10{sup 4} {micro}L L{sup {minus}1} in the prairie and cultivated sites, respectively. Concentrations generally increased with depth, with maximum soil air N{sub 2}O and CO{sub 2} concentrations at 1.0 m in the prairie site and 0.5 m in the cultivated site. Nitrous oxide in the cultivated site and CO{sub 2} at both sites did not change markedly over winter months, but CO{sub 2} and N{sub 2}O concentrations reached maximums during the summer months and decreased as the year progressed. Although soil air concentrations peaked and decreased faster at shallower depths, deeper depths exhibited relative maximum concentrations for longer time periods.

  12. Radiation performance of AlGaAs concentrator cells and expected performance of cascade structures

    NASA Technical Reports Server (NTRS)

    Curtis, Henry B.; Swartz, Clifford K.; Hart, Russell E., Jr.

    1987-01-01

    Aluminum gallium arsenide, GaAs, silicon and InGaAs cells have been irradiated with 1 MeV electrons and 37 MeV protons. These cells are candidates for individual cells in a cascade structure. Data is presented for both electron and proton irradiation studies for one sun and a concentration level of 100X AMO. Results of calculations on the radiation resistance of cascade cell structures based on the individual cell data are also presented. Both series connected and separately connected structures are investigated.

  13. Clinical profile and treatment outcome of older (>75 years) patients with systemic AL amyloidosis

    PubMed Central

    Sachchithanantham, Sajitha; Offer, Mark; Venner, Christopher; Mahmood, Shameem A.; Foard, Darren; Rannigan, Lisa; Lane, Thirusha; Gillmore, Julian D.; Lachmann, Helen J.; Hawkins, Philip N.; Wechalekar, Ashutosh D.

    2015-01-01

    Systemic AL amyloidosis, a disease with improving outcomes using novel therapies, is increasingly recognized in the elderly but treatment and outcomes have not been systematically studied in this group of patients in whom comorbidities and frailty may compound morbidity and mortality. We report the outcomes of 295 patients with systemic AL amyloidosis ≥75 years seen at the UK National Amyloidosis Centre from 2005–2012. The median age was 78.5 years. The median overall survival was 20 months. Two hundred and thirty-eight patients received chemotherapy and 57 elected for supportive care only (overall survival – 24 and 8.4 months, respectively). On intention-to-treat analysis, 44% achieved a hematologic response including a very good partial response or better in 23%. The median overall survival was 6.2 years in patients achieving very good partial response or better at the 6-month landmark analysis and 1.5 years in non-responders. Factors independently indicating a poor prognosis were: cardiac involvement, performance status ≥2; systolic blood pressure <100 mmHg and, on landmark analysis, achieving less than a very good partial response. Treatment of systemic AL amyloidosis in the elderly is challenging. Deep clonal responses are associated with excellent survival and organ responses. Achieving a response to the first-line regimen appears particularly important as outcomes of non-responders are similar to those of untreated patients. Prospective trials with lower toxicity, outpatient treatment regimens are needed. PMID:26294730

  14. Interspecific differences in concentrations and congener profiles of chlorinated and brominated organic pollutants in three insectivorous bird species.

    PubMed

    Dauwe, Tom; Van den Steen, Evi; Jaspers, Veerle L B; Maes, Koen; Covaci, Adrian; Eens, Marcel

    2009-02-01

    We investigated the accumulation of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs) in eggs of three insectivorous bird species, the great tit (Parus major), the Northern lapwing (Vanellus vanellus) and the Mediterranean gull (Larus melanocephalus), near the harbour of Antwerp (Belgium). Our results show that lapwing eggs had the highest median concentrations of PCBs (4358 ng/g lw) and PBDEs (109 ng/g lw). Mediterranean gulls feed during breeding on ground-dwelling invertebrates on agricultural fields, which is reflected in higher OCP concentrations in eggs (1235 ng/g lw). Apart from differences in accumulation, also interspecific differences in contaminant profiles were investigated. Significant differences among species were found in the profile of PCBs, PBDEs and OCPs. These differences could be attributed to differences in diet, behaviour and metabolic capacity. Interestingly, the OCP profile in lapwing eggs deviated extremely from the two other species. In both great tit and Mediterranean gull eggs p,p'-DDE was by far the most important compound, whereas in lapwing eggs hexachlorobenzene, oxychlordane, trans-nonachlor and even p,p'-DDT were relatively more abundant than p,p'-DDE. The high p,p'-DDT/p,p'-DDE ratio has previously been described in lapwings, which suggests that low p,p'-DDE accumulation in eggs might be inherent for this species. PMID:18947874

  15. [Distribution characteristics of soil profile nitrous oxide concentration in paddy fields with different rice-upland crop rotation systems].

    PubMed

    Liu, Ping-li; Zhang, Xiao-lin; Xiong, Zheng-qin; Huang, Tai-qing; Ding, Min; Wang, Jin-yang

    2011-09-01

    To investigate the dynamic distribution patterns of nitrous oxide (N2O) in the soil profiles in paddy fields with different rice-upland crop rotation systems, a special soil gas collection device was adopted to monitor the dynamics of N2O at the soil depths 7, 15, 30, and 50 cm in the paddy fields under both flooding and drainage conditions. Two rotation systems were installed, i.e., wheat-single rice and oilseed rape-double rice, each with or without nitrogen (N) application. Comparing with the control, N application promoted the N2O production in the soil profiles significantly (P < 0.01), and there existed significant correlations in the N2O concentration among the four soil depths during the whole observation period (P < 0.01). In the growth seasons of winter wheat and oilseed rape under drainage condition and with or without N application, the N2O concentrations at the soil depths 30 cm and 50 cm were significantly higher than those at the soil depths 7 cm and 15 cm; whereas in the early rice growth season under flooding condition and without N application, the N2O concentrations at the soil depth 7 cm and 15 cm were significantly higher than those at the soil depths 30 cm and 50 cm (P < 0.05). No significant differences were observed in the N2O concentrations at the test soil depths among the other rice cropping treatments. The soil N2O concentrations in the treatments without N application peaked in the transitional period from the upland crops cropping to rice planting, while those in the treatments with N application peaked right after the second topdressing N of upland crops. Relatively high soil N2O concentrations were observed at the transitional period from the upland crops cropping to rice planting. PMID:22126049

  16. Concentrations and composition profiles of parabens in currency bills and paper products including sanitary wipes.

    PubMed

    Liao, Chunyang; Kannan, Kurunthachalam

    2014-03-15

    Parabens (alkyl esters of p-hydroxybenzoic acid) are widely used as antimicrobial preservatives in personal care products, pharmaceuticals, and foodstuffs. Although parabens have been reported to be used as antimicrobials in certain types of papers (e.g., wet sanitary or hygiene wipes), little is known about the occurrence of these compounds in paper products. In this study, we determined the concentrations of six paraben analogs, methyl (MeP), ethyl (EtP), propyl (PrP), butyl (BuP), benzyl (BzP), and heptyl parabens (HepP), in 253 paper products divided into 18 categories, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). At least one of the six parabens was detected in almost all (detection rate: 98%) paper samples, and the total concentrations (∑PBs; sum of six parabens) ranged from 1.85 to 3,220,000 ng/g (geometric mean (GM): 103; median: 55.1 ng/g). Sanitary wipes contained very high concentrations of ∑PBs (GM: 8300 ng/g). Paper currencies, tickets, business cards, food cartons, flyers, and newspapers contained notable concentrations of ∑PBs, and the GM concentrations in these paper categories were on the order of a few tens to thousands of nanograms per gram. One source of parabens in paper products is the use of these chemicals as antifungal agents. MeP and PrP were the predominant analogs, accounting for approximately 62% and 16% of the total concentrations of parabens, respectively. On the basis of measured concentrations and frequency of handling of paper products, we estimated the daily intake (EDI) of parabens through dermal absorption. The GM and 95th percentile EDI values were 6.31 and 2050 ng/day, respectively, for the general population. Among the paper categories analyzed, sanitary wipes contributed to the majority (>90%) of the exposures. PMID:24419282

  17. Tracking control of concentration profiles in a fed-batch bioreactor using a linear algebra methodology.

    PubMed

    Rómoli, Santiago; Serrano, Mario Emanuel; Ortiz, Oscar Alberto; Vega, Jorge Rubén; Eduardo Scaglia, Gustavo Juan

    2015-07-01

    Based on a linear algebra approach, this paper aims at developing a novel control law able to track reference profiles that were previously-determined in the literature. A main advantage of the proposed strategy is that the control actions are obtained by solving a system of linear equations. The optimal controller parameters are selected through Monte Carlo Randomized Algorithm in order to minimize a proposed cost index. The controller performance is evaluated through several tests, and compared with other controller reported in the literature. Finally, a Monte Carlo Randomized Algorithm is conducted to assess the performance of the proposed controller. PMID:25627329

  18. Capacitance behavior of InAlN Schottky diodes in presence of large concentrations of shallow and deep states related to oxygen

    SciTech Connect

    Py, M. A. Lugani, L.; Taniyasu, Y.; Carlin, J.-F.; Grandjean, N.

    2015-05-14

    The capacitance-voltage-temperature characteristics of nonintentionally doped In{sub 0.16}Al{sub 0.84 }N/n{sup +}-GaN Schottky diodes were measured at 1 MHz and in the 90–400 K range. They are discussed in the framework of existing theories, which properly treat the Poisson's equation, especially near the edge of the space-charge region, the so-called transition region. The concentration of a shallow donor and of a deep DX-like center, previously reported, is properly determined. The key parameter to discuss the temperature dependence of the capacitance is the ratio between the frequency of the small ac modulating signal and the temperature-dependent emission rate associated to each level. The capacitance-voltage C-V{sub a} curves were successfully fitted using a three parameters expression over the full range of temperatures. The concentration of both shallow and deep levels exceeds a few 10{sup 18} cm{sup −3}. Based on secondary ion mass spectrometry profiling, we assign both levels to the dominant oxygen impurity. This result supports our previous assignment of the shallow donor to a substitutional oxygen atom on a nitrogen site and the deep state to an O-related DX center, naturally explaining its high concentration. The sluggish kinetics at low temperatures, associated to the large concentration of deep levels located near the transition region, is illustrated by hysteresis loops in the C-V{sub a} curves below 270 K. Furthermore, the contribution of free carriers to the capacitance is revealed below 150 K, when both shallow and deep donors cannot respond anymore due to an emission rate lower than the 1 MHz modulating frequency. Finally, the presence of a highly doped thin surface barrier, as already reported in other III-nitrides, finds further support.

  19. Multisensor profiling of a concentric gravity wave event propagating from the troposphere to the ionosphere

    NASA Astrophysics Data System (ADS)

    Azeem, Irfan; Yue, Jia; Hoffmann, Lars; Miller, Steven D.; Straka, William C.; Crowley, Geoff

    2015-10-01

    In this paper, we present near-simultaneous observations of a gravity wave (GW) event in the stratosphere, mesosphere, and ionosphere over the South Central United States and track it from its convective source region in the troposphere to the ionosphere, where it appears as a traveling ionospheric disturbance (TID). On 4 April 2014 concentric GW ring patterns were seen at stratospheric heights in close proximity to a convective storm over North Texas in the Atmospheric Infrared Sounder data on board the NASA Aqua satellite. Concentric GWs of similar orientation and epicenter were also observed in mesospheric nightglow measurements of the Day/Night Band of the Visible/Infrared Imaging Radiometer Suite on the Suomi National Polar-orbiting Partnership satellite. Concentric TIDs were seen in total electron content data derived from ground-based GPS receivers distributed throughout the U.S. These new multisensor observations of TIDs and atmospheric GWs can provide a unique perspective on ionosphere-atmosphere coupling.

  20. Depth profiling of photothermal compound concentrations using phase sensitive optical coherence tomography

    PubMed Central

    Guan, Guangying; Reif, Roberto; Huang, Zhihong; Wang, Ruikang K.

    2011-01-01

    A model that describes the concentration of photothermal (light-to-heat converters) compounds as a function of depth in a turbid medium is developed. The system consists of a pump laser (808 nm modulated at 400 Hz), which heats a photothermal compound, and a phase sensitive spectral domain optical coherence tomography system, which detects the changes in the optical path length of the sample induced by the temperature increase. The model is theoretically derived and the coefficients are empirically determined using solid homogeneous gel phantoms. The model is validated by reconstructing the concentration of a photothermal compound in thick single and double layer solid phantoms. PMID:22191920

  1. Anomalous glass transition behavior of SBR-Al2O3 nanocomposites at small filler concentrations

    NASA Astrophysics Data System (ADS)

    Sushko, Rymma; Filimon, Marlena; Dannert, Rick; Elens, Patrick; Sanctuary, Roland; Baller, Jörg

    2014-10-01

    Elastomers filled with hard nanoparticles are of great technical importance for the rubber industry. In general, fillers improve mechanical properties of polymer materials, e.g. elastic moduli, tensile strength etc. The smaller the size of the particles, the larger is the interface where interactions between polymer molecules and fillers can generate new properties. Using temperature-modulated differential scanning calorimetry and dynamic mechanical analysis, we investigated the properties of pure styrene-butadiene rubber (SBR) and SBR/alumina nanoparticles. Beside a reinforcement effect seen in the complex elastic moduli, small amounts of nanoparticles of about 2 wt% interestingly lead to an acceleration of the relaxation modes responsible for the thermal glass transition. This leads to a minimum in the glass transition temperature as a function of nanoparticle content in the vicinity of this critical concentration. The frequency dependent elastic moduli are used to discuss the possible reduction of the entanglement of rubber molecules as one cause for this unexpected behavior.

  2. Loss of Body Weight and Fat and Improved Lipid Profiles in Obese Rats Fed Apple Pomace or Apple Juice Concentrate

    PubMed Central

    Cho, Kyung-Dong; Han, Chan-Kyu

    2013-01-01

    Abstract The purpose of this study was to investigate the influence of apple pomace (AP) and apple juice concentrate (AC) supplementation on body weight and fat loss as well as lipid metabolism in obese rats fed a high-fat diet. Diet-induced obese rats were assigned to three groups (n=8 for each group): high fat diet (HFD) control, HFD containing 10% (w/w) AP, and HFD containing 10% (w/w) AC. There was also a normal diet group (n=8). After 5 weeks, body weight gain, adipose tissue weight, serum and hepatic lipid profiles, liver morphology, and adipocyte size were measured. Body weight gain, white adipose tissue (WAT) weight, serum total cholesterol, low-density lipoprotein cholesterol and triglyceride concentrations, epididymal adipocyte size, and lesion scores were significantly lower and serum high-density lipoprotein cholesterol concentration and brown adipose tissue weights were significantly higher in the AP and AC groups compared with the HFD group. In addition, atherogenic indices in the AP and AC groups were significantly lower than in the HFD group. These results indicate that supplementing apple products such as AP and AC may help suppress body weight and WAT gain, as well as improve lipid profiles in diet-induced obese rats. PMID:23909905

  3. Dial Measurements of Free-Tropospheric Ozone Profiles in Huntsville, AL

    NASA Technical Reports Server (NTRS)

    Newchurch, Mike; Kuang, Shi; Burris, John; Johnson, Steve; Long, Stephanie

    2008-01-01

    A tropospheric ozone DIfferential Absorption Lidar (DIAL) system has been developed jointly by NASA and the University of Alabama at Huntsville (UAH). Two separated Nd:YAG pumped dye laser systems produce the laser pulses with wavelengths of 285 and 291 nm at 20 Hz frequency. The receiver is a Newtonian telescope with a 40 cm primary and a two-channel aft optics unit. The detection system currently uses photon counting to facilitate operations at the maximum achievable altitude. This lidar measures free-tropospheric ozone profiles between 4-10 km at Regional Atmospheric Profiling Laboratory for Discovery (RAPCD) in UAH campus (ASL 206 m) under both daytime and nighttime conditions. Frequent coincident ozonesonde flights and theoretical calculations provide evidence to indicate the retrieval accuracy ranges from approx.5% at 4 km to approx.60% at 10 km with 750-m vertical resolution and 30-minute integration. Three Hamamatsu 7400 PMTs and analog detection technique will be added on the current system to extend the measurement to approx.100 m above ground to monitor the PBL and lower tropospheric ozone variations.

  4. Phthalate metabolites in urine of Chinese young adults: Concentration, profile, exposure and cumulative risk assessment.

    PubMed

    Gao, Chong-Jing; Liu, Li-Yan; Ma, Wan-Li; Ren, Nan-Qi; Guo, Ying; Zhu, Ning-Zheng; Jiang, Ling; Li, Yi-Fan; Kannan, Kurunthachalam

    2016-02-01

    Phthalates are widely used in consumer products. People are frequently exposed to phthalates due to their applications in daily life. In this study, 14 phthalate metabolites were analyzed in 108 urine samples collected from Chinese young adults using high-performance liquid chromatography-tandem mass spectrometry. The total concentrations of 14 phthalate metabolites ranged from 71.3 to 2670 ng/mL, with the geometric mean concentration of 306 ng/mL. mBP and miBP were the two most abundant compounds, accounting for 48% of the total concentrations. Principal component analysis suggested two major sources of phthalates: one dominated by the DEHP metabolites and one by the group of mCPP, mBP and miBP metabolites. The estimated daily intakes of DMP, DEP, DBP, DiBP and DEHP were 1.68, 2.14, 4.12, 3.52 and 1.26-2.98 μg/kg-bw/day, respectively. In a sensitivity analysis, urinary concentration and body weight were the most influential variables for human exposure estimation. Furthermore, cumulative risk for hazard quotient (HQ) and hazard index (HI) were evaluated. Nearly half of Chinese young adults had high HI values exceeding the safe threshold. This is the first study on the occurrence and human exposure to urinary phthalate metabolites with Chinese young adults. PMID:26575634

  5. MRI profiles over very wide concentration ranges: application to swelling of a bentonite clay.

    PubMed

    Dvinskikh, S V; Szutkowski, K; Furó, I

    2009-06-01

    In MRI investigation of soils, clays, and rocks, mainly mobile water is detected, similarly to that in biological and medical samples. However, the spin relaxation properties of water in these materials and/or low water concentration may make it difficult to use standard MRI approaches. Despite these limitations, one can combine MRI techniques developed for solid and liquid states and use independent information on relaxation properties of water, interacting with the material of interest, to obtain true images of both water and material content. We present procedures for obtaining such true density maps and demonstrate their use for studying the swelling of bentonite clay by water. A constant time imaging protocol provides 1D mapping of the clay distribution in regions with clay concentration above 10 vol%. T(1) relaxation time imaging is employed to monitor the clay content down to 10(-3) vol%. Data provided by those two approaches are in good agreement in the overlapping range of concentrations. Covering five orders of magnitude of clay concentration, swelling of sodium-exchanged bentonite clays from pre-compacted pellets into a gel phase is followed in detail. PMID:19233697

  6. MRI profiles over very wide concentration ranges: Application to swelling of a bentonite clay

    NASA Astrophysics Data System (ADS)

    Dvinskikh, S. V.; Szutkowski, K.; Furó, I.

    2009-06-01

    In MRI investigation of soils, clays, and rocks, mainly mobile water is detected, similarly to that in biological and medical samples. However, the spin relaxation properties of water in these materials and/or low water concentration may make it difficult to use standard MRI approaches. Despite these limitations, one can combine MRI techniques developed for solid and liquid states and use independent information on relaxation properties of water, interacting with the material of interest, to obtain true images of both water and material content. We present procedures for obtaining such true density maps and demonstrate their use for studying the swelling of bentonite clay by water. A constant time imaging protocol provides 1D mapping of the clay distribution in regions with clay concentration above 10 vol%. T1 relaxation time imaging is employed to monitor the clay content down to 10 -3 vol%. Data provided by those two approaches are in good agreement in the overlapping range of concentrations. Covering five orders of magnitude of clay concentration, swelling of sodium-exchanged bentonite clays from pre-compacted pellets into a gel phase is followed in detail.

  7. Alkaloid Profiles, Concentration and Pools in Velvet Lupine (Lupinus leucophyllus) Over the Growing Season

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lupinus leucophyllus is one of many lupine species known to contain toxic and/or teratogenic alkaloids that can cause congenital birth defects. The concentrations of total alkaloids and the individual major alkaloids were measured in three different years from different plant parts over the phenolog...

  8. Effect of concentrate supplementation on performance, ovarian response, and some biochemical profile of Malpura ewes.

    PubMed

    Naqvi, S M K; Soren, N M; Karim, S A

    2011-06-01

    Effect of feed flushing on ovulation rate was investigated during the autumn seasons on 24 adult Malpura ewes (BW 34.8 ± 0.58 kg and age 4-7 years) equally divided into two groups. Ewes in G1 (group 1) were grazed 8-10 h daily on Cenchrus ciliaris pasture interspersed with seasonal shrub. In addition to grazing, concentrate was provided at 1.5% of BW to the animals in G2 (group 2) for a period of 35 days. Estrus was synchronized by a double injection schedule of PGF(2α) at 0 and 10 days of the experiment and detected by parading aproned rams at 6 h intervals. Blood samples were collected at weekly interval during the estrous cycle. A rumen fermentation study was conducted on day 23 of the experiment at 0 and 4 h post-concentrate feeding. Ovarian responses in terms of number of corpora lutea and large follicles was examined on all the ewes by laparoscopy after 3 to 6 days of each estrus and were found to be similar in both the groups. Hemoglobin and packed cell volume, total protein, albumin, and globulin were similar among the groups. Concentration of plasma glucose (12 and 22 days) was higher (P < 0.05) in G2 vis-à-vis control. Plasma urea was higher (P < 0.01) in the control than G2. Rumen liquor pH, concentration of total N, TCA-ppt N, NH(3)-N, and TVFA were significantly higher (P < 0.01) in G2 than the control. Thus, it can be concluded that concentrate supplementation in ewes prior to mating (flushing) did not enhance ovulation response during the autumn season. PMID:21287364

  9. Cytokine profile in cases with premature elevation of progesterone serum concentrations during ovarian stimulation.

    PubMed

    Nikolettos, N; Asimakopoulos, B; Köster, F; Schöpper, B; Schulz, Ch; Caglar, G S; Efthimiadou, A; Pagonopoulou, O; Diedrich, K; Al-Hasani, S

    2008-01-01

    The aim of this study was to investigate the concentrations of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), leptin, tumor necrosis factor-alpha, interleukin (IL)-1beta and IL-6, in cycles with a premature rise of serum progesterone. 25 intracytoplasmic sperm injection (ICSI) cycles with (Group 1) and 25 ICSI cycles without a premature progesterone elevation (Group 2) were included. The cut-off value of serum progesterone on the day of human chorionic gonadotropin (hCG) administration was 0.9 ng/ml. The indication for ICSI was male factor infertility exclusively. On the day of hCG injection, serum IL-6, VEGF and bFGF were significantly higher in Group 1 (7.7+/-24.5 pg/ml, 290.2+/-161.4 pg/ml and 15.7+/-8.2 ng/ml respectively) than in Group 2 (1.7+/-0.7 pg/ml, 175.2+/-92.1 pg/ml, and 9+/-1.6 ng/ml respectively). On the day of follicular puncture, serum cytokine concentrations were similar in the two groups. IL-6 intrafollicular concentrations were higher in Group 1 (14.7+/-20.7 pg/ml) than in Group 2 (9+/-9.3 pg/ml, p=0.031). There were no differences regarding the ICSI outcome. Patients with serum progesterone above 0.9 ng/ml, have elevated serum concentrations of IL-6, VEGF, and bFGF, as well as elevated intrafollicular concentrations of IL-6. The outcome of ICSI cycles is not associated with premature elevation of progesterone when the cut-off value is set at 0.9 ng/ml. PMID:17298206

  10. Lead fluxes, isotopic and concentration profiles in a peat deposit near a lead smelter (Príbram, Czech Republic).

    PubMed

    Mihaljevic, M; Zuna, M; Ettler, V; Sebek, O; Strnad, L; Goliás, V

    2006-12-15

    The content and the isotopic composition of lead (Pb) were studied in a peat deposit on the ridge of the Brdy Hills, in the vicinity of the Príbram metallurgical works, in the Czech Republic. Quadrupole ICP MS was employed to determine the elemental composition and (206)Pb/(207)Pb and (208)Pb/(206)Pb isotope ratios. The individual layers were dated using alpha spectrometric measurement of the (210)Pb activity. The historical time period covered by the studied cores reached back to the 18th century. The Pb concentration in the studied profiles varied from 10 to 550 mg kg(-1). The (206)Pb/(207)Pb ratio varied in the range from 1.154 to 1.194 in the individual parts of the profile. The metallurgy of the Pb ores ((206)Pb/(207)Pb approximately 1.16), lithogenic Pb ((206)Pb/(207)Pb approximately 1.2), metallurgical processing of automobile batteries ((206)Pb/(207)Pb approximately 1.17) and the combustion of coal ((206)Pb/(207)Pb approximately 1.17-1.19) yield isotopic signatures that determine the isotope compositions of the individual profiles. Deposition rates between 15 mg m(-2) year(-1) at the beginning of the 19th century and 320 mg m(-2) year(-1) in the 1980s were determined in the dated profiles. The increased deposition rates determined on the dated profiles correspond to the increasing production of Pb ores in the Príbram mining area at the turn of the 19th and 20th centuries. The maximum for metallurgical production corresponds to the highest deposition rates recorded in 1960s and 1970s. The current deposition rate of 5-89 mg m(-2) year(-1) Pb is related to erosion of contaminated soils and waste dumps. PMID:17081595

  11. Spontaneous polarization driven Mg concentration profile reconstruction in MgZnO/ZnO heterostructures

    SciTech Connect

    Imasaka, K.; Falson, J.; Kozuka, Y. Kawasaki, M.; Tsukazaki, A.

    2014-06-16

    Atomic reconstruction at the interface of MgZnO and ZnO in molecular beam epitaxy grown heterostructures is investigated. Using secondary ion mass spectroscopy, we experimentally find that Mg atomic reconstruction depends on the polarity of the interface; it is not observed in n-type interfaces (MgZnO on Zn-polar ZnO) owing to electron accumulation, while in p-type interfaces (ZnO on Zn-polar MgZnO), Mg drastically redistributes into the ZnO layer. Combined with self-consistent calculation of band profiles and carrier distributions, we reveal that the observed Mg reconstruction is not due to thermal diffusion but consequences in order to avoid hole accumulation. This tendency implies inherent significant asymmetry of energy scales of atomic and electronic reconstructions between n-type and p-type interfaces.

  12. Tracer concentration profiles measured in central London as part of the REPARTEE campaign

    NASA Astrophysics Data System (ADS)

    Martin, D.; Petersson, K. F.; White, I. R.; Henshaw, S. J.; Nickless, G.; Lovelock, A.; Barlow, J. F.; Dunbar, T.; Wood, C. R.; Shallcross, D. E.

    2009-11-01

    There have been relatively few tracer experiments carried out that have looked at vertical plume spread in urban areas. In this paper we present results from cyclic perfluorocarbon tracer experiments carried out in 2006 and 2007 in central London centred on the BT Tower as part of the REPARTEE (Regent's Park and Tower Environmental Experiment) campaign. The height of the tower gives a unique opportunity to study dispersion over a large vertical gradient. These gradients are then compared with classical Gaussian profiles of the relevant stability classes over a range of distances as well as interpretation of data with reference to both anemometry and LIDAR measurements made. Data are then compared with an operational model and contrasted with data taken in central London as part of the DAPPLE campaign looking at dosage compared with non-dimensionalised distance from source. Such analysis illustrates the feasibility of the use of these empirical correlations over these prescribed distances in central London.

  13. Tracer concentration profiles measured in central London as part of the REPARTEE campaign

    NASA Astrophysics Data System (ADS)

    Martin, D.; Petersson, K. F.; White, I. R.; Henshaw, S. J.; Nickless, G.; Lovelock, A.; Barlow, J. F.; Dunbar, T.; Wood, C. R.; Shallcross, D. E.

    2011-01-01

    There have been relatively few tracer experiments carried out that have looked at vertical plume spread in urban areas. In this paper we present results from two tracer (cyclic perfluorocarbon) experiments carried out in 2006 and 2007 in central London centred on the BT Tower as part of the REPARTEE (Regent's Park and Tower Environmental Experiment) campaign. The height of the tower gives a unique opportunity to study vertical dispersion profiles and transport times in central London. Vertical gradients are contrasted with the relevant Pasquill stability classes. Estimation of lateral advection and vertical mixing times are made and compared with previous measurements. Data are then compared with a simple operational dispersion model and contrasted with data taken in central London as part of the DAPPLE campaign. This correlates dosage with non-dimensionalised distance from source. Such analyses illustrate the feasibility of the use of these empirical correlations over these prescribed distances in central London.

  14. Concentrations and profiles of PCDD/Fs in sediments of major Polish rivers and the Gdansk Basin--Baltic Sea.

    PubMed

    Niemirycz, Elżbieta; Jankowska, Daria

    2011-10-01

    The present state of contamination of bottom sediments in southern part of the Baltic Sea with PCDD/Fs was compared to the findings made for the north-western and eastern Baltic Sea coastal areas of Finland, Sweden and Denmark. The extent of the study area--from marine the Gdańsk Basin, the lower Oder and Vistula Rivers up till Włocławek reservoir--allowed to obtain the sediment samples with diversified properties. Dioxin's concentrations in sediments examined in the Polish costal area allows us to evaluate this zone as relatively less contaminated. Higher dioxin concentration has been found in Wloclawek Dam Reservoir. Differences in congener patterns and temporal changes in marine sediment profiles were examined. The highest concentrations of tetra- and penta-congeners still remain in the surface layer of Gdansk Deep, whereas the decline in concentrations of these most toxic congeners, have been observed in the sediments from some other parts of the Baltic coast. Excess concentration of dioxins in sediments has a great impact on human being due to special ability of accumulation in the trophic chain as well as in water (fishes) and land (milk, meat). PMID:21917292

  15. Generation of arbitrary monotonic concentration profiles by a serial dilution microfluidic network composed of microchannels with a high fluidic-resistance ratio.

    PubMed

    Hattori, Koji; Sugiura, Shinji; Kanamori, Toshiyuki

    2009-06-21

    This paper reports a serial dilution microfluidic network composed of microchannels with a high fluidic-resistance ratio for generating linear concentration profiles as well as logarithmic concentration profiles spanning 3 and 6 orders of magnitude. The microfluidic networks were composed of thin fluidic-resistance microchannels with 160 to 730 microm(2) cross-sectional areas and thick diffusion-mixing microchannels with 3,600 to 17,000 microm(2) cross-sectional areas, and were fabricated from polydimethylsiloxane by multilayer photolithography and replica molding. We proposed a design algorithm of the microfluidic network for an arbitrary monotonic concentration profile by means of a hydrodynamic calculation. Because of the high fluidic-resistance ratio of the fluidic-resistance microchannels to the diffusion-mixing microchannels, appropriate geometry and dimensions of the fluidic-resistance microchannels allowed us to obtain desired concentration profiles. The fabricated microfluidic network was compact, occupying a 8 x 18 to 21.0 x 13.5 mm(2) area on the microchip. Both the linear and the logarithmic concentration profiles were successfully generated with the error less than 15% for the linear concentration profile, 22% and 35% for the logarithmic concentration profiles of 3 and 6 orders of magnitude, respectively. The generated linear concentration profiles of the small molecule, calcein, were independent of the flow rate within the range of 0.009 to 0.23 microL/min. The concentration profiles of the large molecules, dextrans, depended on the flow rate and molecular weight. The required residence time of large molecules in the diffusion-mixing microchannel was correlated with dimensionless diffusion time, Fick number, and was discussed based on the scaling law. These compact, stable serial dilution microfluidic networks are expected to be applied to various integrated on-chip analyses. PMID:19495461

  16. An Asia-specific source of dechlorane plus: concentration, isomer profiles, and other related compounds.

    PubMed

    Wang, De-Gao; Yang, Meng; Qi, Hong; Sverko, Ed; Ma, Wan-Li; Li, Yi-Fan; Alaee, Mehran; Reiner, Eric J; Shen, Li

    2010-09-01

    The distribution of dechloranes, a group of chlorinated flame retardants, were investigated in air, soil, and sediment around a newly discovered Dechlorane Plus (DP) production facility in China (Anpon). To date, the only known DP manufacturing plant is located in Niagara Falls, NY (OxyChem). Dechloranes including DP, Dechlorane (Mirex), and the recently discovered Dechlorane 602 (Dec 602) were detected in air, soil, and sediment, while Dechlorane 603 and Dechlorane 604 were below detection limit in all matrices. DP air concentrations near the facility ranged from 7737 to 26 734 pg m(-3), the greatest reported thus far. Soil concentrations in the same area for DP, Dechlorane, and Dec 602 were 1490+/-3580 ng g(-1), 81.6+/-96.5 ng g(-1), and 7.24+/-13.2 ng g(-1) dry weight, respectively. Interestingly, lower concentrations of DP (4.93+/-4.34 ng g(-1)), Dechlorane (30.2+/-19.9 ng g(-1)), and Dec 602 (2.14+/-2.23 ng g(-1)) were found in sediment from a nearby canal. Spatial trends of Dechlorane and Dec 602 in soil were similar to DP, implying that the DP manufacturing plant may also be a source of these other flame retardants. DP soil concentrations surrounding the facility decreased by an order of magnitude within 7.5 km. The syn-DP fractional abundance (fsyn) value (0.40) for the commercial DP product manufactured at Anpon was slightly higher than that (0.20-0.36) produced by OxyChem. The fsyn value in most air samples was largely similar to the Chinese commercial DP mixture, while most soil and sediment abundances were lower, suggesting a stereoselective depletion of syn-DP. PMID:20681512

  17. Response of pore water Al, Fe and S concentrations to waterlogging in a boreal acid sulphate soil.

    PubMed

    Virtanen, Seija; Simojoki, Asko; Hartikainen, Helinä; Yli-Halla, Markku

    2014-07-01

    Environmental hazards caused by acid sulphate (AS) soils are of worldwide concern. Among various mitigation measures, waterlogging has mainly been studied in subtropical and tropical conditions. To assess the environmental relevance of waterlogging as a mitigation option in boreal AS soils, we arranged a 2.5-year experiment with monolithic lysimeters to monitor changes in the soil redox potential, pH and the concentrations of aluminium (Al), iron (Fe) and sulphur (S) in pore water in response to low and high groundwater levels in four AS soil horizons. The monoliths consisted of acidic oxidized B horizons and a reduced C horizon containing sulphidic material. Eight lysimeters were cropped (reed canary grass, Phalaris arundinacea) and two were bare without a crop. Waterlogging was conducive to reduction reactions causing a slight rise in pH, a substantial increase in Fe (Fepw) and a decrease in Al (Alpw) in the pore water. The increase in Fepw was decisively higher in the cropped waterlogged lysimeters than in the bare ones, which was attributable to the microbiologically catalysed reductive dissolution of poorly ordered iron oxides and secondary minerals. In contrast to warmer climates, Fepw concentrations remained high throughout the experiment, indicating that the reduction was poised in the iron range, while sulphate was not reduced to sulphide. Therefore, the precipitation of iron sulphide was negligible in the environment with a low pH and abundant with poorly ordered Fe oxides. Increased Fe in pore water counteracts the positive effects of waterlogging, when water is flushed from fields to watercourses, where re-oxidation of Fe causes acidity and oxygen depletion. However, waterlogging prevented further oxidation of sulphidic materials and decreased Alpw to one-tenth of the initial concentrations, and even to one-hundredth of the levels in the low water table lysimeters. PMID:24704964

  18. Polybrominated diphenyl ethers in sediments from the Southern Yellow Sea: Concentration, composition profile, source identification and mass inventory.

    PubMed

    Wang, Guoguang; Peng, Jialin; Xu, Xiang; Zhang, Dahai; Li, Xianguo

    2016-02-01

    The Southern Yellow Sea (SYS) is believed to be influenced by the contaminants from mainland China and the Korean peninsula. Here we report the first record about concentrations of polybrominated diphenyl ethers (PBDEs) in the sediments of the SYS. The concentrations of ∑(7)PBDEs (BDE-28, 47, 99, 100, 153, 154, 183) and BDE-209 were 0.064-0.807 ng g(-1) (dry weight) and 0.067-1.961 ng g(-1) with a mean value of 0.245 ng g(-1) and 0.652 ng g(-1), respectively. These are distinctively low compared with the PBDE levels previously reported in other regions of the world. PBDE concentrations gradually increased from the coastal areas to the central mud area. BDE-209 was the dominant congener, accounting for 70.2-91.6% of the total PBDEs. Congener profiles of PBDEs were similar to those in sediments from the Bohai Sea (BS), Laizhou Bay and modern Yellow River, which might be a tentative indication that they shared similar sources. Principal component analysis (PCA) revealed that PBDEs in the SYS were mainly from continental runoff (69.0%) and atmospheric deposition (31.0%). Depth profile of PBDEs in a sediment core collected from the edge of the central mud area showed that concentration of BDE-209 rapidly increased in recent years, which is in accordance with the replacement in demand and consumption of Penta- and Octa-BDEs by the Deca-BDE. Compared with BS, East China Sea, Erie and Ontario, the SYS was a relatively weak sink of PBDEs (0.102-1.288 t yr(-1) for ∑(7)PBDEs and 0.107-3.129 t yr(-1) for BDE-209) in the world. PMID:26580721

  19. Concentrations and profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans in soils from Korea.

    PubMed

    Im, Sook Hyeon; Kannan, Kurunthachalam; Giesy, John P; Matsuda, Muneaki; Wakimoto, Tadaaki

    2002-09-01

    Soil samples were collected from Changwon and Masan Cities, Korea, and analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs). Nearly all tetra- through octachlorinated PCDDs/DFs including the 17 2,3,7,8-substituted PCDDs/DFs were detected in all samples. Total concentrations of PCDDs/DFs and of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TeCDD) equivalents (TEGs) in soils ranged from 35 to 121,400 pg/g, dry weight, and from 0.2 to 3720 pg of I-TEQ/g, respectively. On the basis of guidelines for TEQ concentrations established in Germany and the United States, 9 of 23 soil samples (39% of the total samples analyzed) could not be expected to pose human health hazards. The rest of 61% of soils need measures such as investigations of source identification, soil decontamination, and/or soil removal. Total concentrations of PCDDs/DFs were greater at or near four industrial sites, which are concerned with the steel industry, petrochemical-related industry, and industrial waste incineration, than other areas. This indicates the presence of potential source areas. Soil collected from a site 50 m from an open-burning industrial waste incinerator in an industrial complex was heavily contaminated, containing a total concentration of PCDDs/DFs of 121,400 pg/g, dry weight. PCDDs/DFs were also detected in soils from the top of a 200 m mountain indicating a wide dispersal of PCDDs/DFs by atmospheric transport from point source areas. The congener pattern and relative proportions of PCDFs in soils suggest that commercial PCB preparations such as Kanechlors may be one of the sources. The wide range of PCDD/DF isomers detected in soils from many locations also suggests a multitude of sources, in addition to commercial PCBs, such as incineration of industrial wastes such as car tires, scrap wires, plastics, papers, and emission of automobile exhaust. PMID:12322740

  20. Driving forces for metamorphic vein filling during bauxite dehydration: insights from Li and Al transfer illustrated by LIBS compositional profiles (Western Alps)

    NASA Astrophysics Data System (ADS)

    Verlaguet, Anne; Brunet, Fabrice; Goffé, Bruno; Menut, Denis; Findling, Nathaniel; Poinssot, Christophe

    2015-04-01

    this closed chemical system, mass transfer from rock to vein was achieved through the fluid, in a dissolution-transport-precipitation process. To investigate the modalities of mass transfer towards this second vein type, LIBS profiles were performed in the host-rock, taking Li concentration as a proxy for cookeite distribution. Cookeite is highly concentrated (45-65 vol%) in regularly spaced veins, and the LIBS profiles show that cookeite is evenly distributed in the host-rock comprised between two veins. The absence of diffusion profiles suggests that the characteristic diffusion distance for Li, Al and Si is greater than or equal to the distance separating two cookeite veins (2-4 cm). This is in agreement with characteristic diffusion lengths calculated from both grain boundary and pore fluid diffusion coefficients, for the estimated duration of the peak of metamorphism. Which driving forces are responsible for cookeite selective transfer towards veins? Chemical potential gradients between host-rock pores and veins may have developed in response to either (1) a stress difference: thermochemical calculations show that pressure-solution processes may affect preferentially cookeite and pyrophyllite; (2) a difference in interfacial energy, phyllosilicates showing very different morphologies in host-rocks (fibers) compared to veins (euhedral crystals); fluid-mineral interfacial energy may be maximal in the small host-rock pores, which can maintain higher cookeite solubility than large fluid-filled open spaces (i.e., veins).

  1. Discrimination among spawning concentrations of Lake Superior lake herring based on trace element profiles in sagittae

    USGS Publications Warehouse

    Bronte, Charles R.; Hesselberg, Robert J.; Shoesmith, John A.; Hoff, Michael H.

    1996-01-01

    Little is known about the stock structure of lake herring Coregonus artedi in Lake Superior, and recent increases in harvestable stock sizes has led to expanded exploitation in some areas. Research on marine teleosts has demonstrated that chemical differences in sagittal otoliths can be used for identification of fish stocks. We used plasma emission spectrophotometry to measure the concentrations of 10 trace elements in the sagittal otoliths from lake herring captured at eight spawning sites in Lake Superior and from Little Star Lake, an inland lake outside the Lake Superior basin. Discriminant function analysis indicated that elemental concentrations provided site-specific information but that considerable overlap existed among some locations, especially those in western Lake Superior. Correct classification rates varied from 12.0% to 86.1% and were generally higher for spawning locations from embayments in eastern Lake Superior and for the outgroup population from Little Star Lake. The results presented here demonstrate the potential usefulness of this technique for strictly freshwater species, especially those that live in highly oligotrophic waters such as Lake Superior.

  2. Neighborhood-Scale Spatial Models of Diesel Exhaust Concentration Profile Using 1-Nitropyrene and Other Nitroarenes.

    PubMed

    Schulte, Jill K; Fox, Julie R; Oron, Assaf P; Larson, Timothy V; Simpson, Christopher D; Paulsen, Michael; Beaudet, Nancy; Kaufman, Joel D; Magzamen, Sheryl

    2015-11-17

    With emerging evidence that diesel exhaust exposure poses distinct risks to human health, the need for fine-scale models of diesel exhaust pollutants is growing. We modeled the spatial distribution of several nitrated polycyclic aromatic hydrocarbons (NPAHs) to identify fine-scale gradients in diesel exhaust pollution in two Seattle, WA neighborhoods. Our modeling approach fused land-use regression, meteorological dispersion modeling, and pollutant monitoring from both fixed and mobile platforms. We applied these modeling techniques to concentrations of 1-nitropyrene (1-NP), a highly specific diesel exhaust marker, at the neighborhood scale. We developed models of two additional nitroarenes present in secondary organic aerosol: 2-nitropyrene and 2-nitrofluoranthene. Summer predictors of 1-NP, including distance to railroad, truck emissions, and mobile black carbon measurements, showed a greater specificity to diesel sources than predictors of other NPAHs. Winter sampling results did not yield stable models, likely due to regional mixing of pollutants in turbulent weather conditions. The model of summer 1-NP had an R(2) of 0.87 and cross-validated R(2) of 0.73. The synthesis of high-density sampling and hybrid modeling was successful in predicting diesel exhaust pollution at a very fine scale and identifying clear gradients in NPAH concentrations within urban neighborhoods. PMID:26501773

  3. Optimizing the Dopant and Carrier Concentration of Ca5Al2Sb6 for High Thermoelectric Efficiency.

    PubMed

    Yan, Yuli; Zhang, Guangbiao; Wang, Chao; Peng, Chengxiao; Zhang, Peihong; Wang, Yuanxu; Ren, Wei

    2016-01-01

    The effects of doping on the transport properties of Ca5Al2Sb6 are investigated using first-principles electronic structure methods and Boltzmann transport theory. The calculated results show that a maximum ZT value of 1.45 is achieved with an optimum carrier concentration at 1000 K. However, experimental studies have shown that the maximum ZT value is no more than 1 at 1000 K. By comparing the calculated Seebeck coefficient with experimental values, we find that the low dopant solubility in this material is not conductive to achieve the optimum carrier concentration, leading a smaller experimental value of the maximum ZT. Interestingly, the calculated dopant formation energies suggest that optimum carrier concentrations can be achieved when the dopants and Sb atoms have similar electronic configurations. Therefore, it might be possible to achieve a maximum ZT value of 1.45 at 1000 K with suitable dopants. These results provide a valuable theoretical guidance for the synthesis of high-performance bulk thermoelectric materials through dopants optimization. PMID:27406178

  4. Optimizing the Dopant and Carrier Concentration of Ca5Al2Sb6 for High Thermoelectric Efficiency

    PubMed Central

    Yan, Yuli; Zhang, Guangbiao; Wang, Chao; Peng, Chengxiao; Zhang, Peihong; Wang, Yuanxu; Ren, Wei

    2016-01-01

    The effects of doping on the transport properties of Ca5Al2Sb6 are investigated using first-principles electronic structure methods and Boltzmann transport theory. The calculated results show that a maximum ZT value of 1.45 is achieved with an optimum carrier concentration at 1000 K. However, experimental studies have shown that the maximum ZT value is no more than 1 at 1000 K. By comparing the calculated Seebeck coefficient with experimental values, we find that the low dopant solubility in this material is not conductive to achieve the optimum carrier concentration, leading a smaller experimental value of the maximum ZT. Interestingly, the calculated dopant formation energies suggest that optimum carrier concentrations can be achieved when the dopants and Sb atoms have similar electronic configurations. Therefore, it might be possible to achieve a maximum ZT value of 1.45 at 1000 K with suitable dopants. These results provide a valuable theoretical guidance for the synthesis of high-performance bulk thermoelectric materials through dopants optimization. PMID:27406178

  5. Optimizing the Dopant and Carrier Concentration of Ca5Al2Sb6 for High Thermoelectric Efficiency

    NASA Astrophysics Data System (ADS)

    Yan, Yuli; Zhang, Guangbiao; Wang, Chao; Peng, Chengxiao; Zhang, Peihong; Wang, Yuanxu; Ren, Wei

    2016-07-01

    The effects of doping on the transport properties of Ca5Al2Sb6 are investigated using first-principles electronic structure methods and Boltzmann transport theory. The calculated results show that a maximum ZT value of 1.45 is achieved with an optimum carrier concentration at 1000 K. However, experimental studies have shown that the maximum ZT value is no more than 1 at 1000 K. By comparing the calculated Seebeck coefficient with experimental values, we find that the low dopant solubility in this material is not conductive to achieve the optimum carrier concentration, leading a smaller experimental value of the maximum ZT. Interestingly, the calculated dopant formation energies suggest that optimum carrier concentrations can be achieved when the dopants and Sb atoms have similar electronic configurations. Therefore, it might be possible to achieve a maximum ZT value of 1.45 at 1000 K with suitable dopants. These results provide a valuable theoretical guidance for the synthesis of high-performance bulk thermoelectric materials through dopants optimization.

  6. Improved Dead Sea sinkhole site characterization at Ghor Al Haditha, Jordan, based on repeated shear wave reflection seismic profiling

    NASA Astrophysics Data System (ADS)

    Polom, Ulrich; Alrshdan, Hussam; Al-Halbouni, Djamil; Sawarieh, Ali; Dahm, Torsten; Krawczyk, CharLotte M.

    2016-04-01

    In October 2014 a high-resolution shallow shear wave reflection seismic survey was carried out at the Dead Sea sinkhole site Ghor Al Haditha, Jordan. It extended a survey undertaken in 2013, also in order to gather time-lapse profiles. In the framework of the DEad SEa Research Venue (DESERVE), a virtual institute of the Helmholtz Association and international partners, this investigation is part of a cross-disciplinary and cooperative international project of the Helmholtz Centers KIT, GFZ, and UFZ. At the investigation site, characterized by alluvial fan deposits, ongoing subsidence and sinkhole processes in the subsurface create massive reshaping of farming areas, including the destruction of housings, industrial sites, and infrastructure. The sinkhole hazard at the Dead Sea is significant, since similar processes are observed at several coastal segments of the Dead Sea. The new survey (in total 2.1 profile km) was targeted to improve the knowledge about the subsurface structures and to confine the results of the initial survey (1.8 km profile km), with respect to the presence or non-presence of a massive salt layer proposed at nearly 40 m depth. This salt layer is the central part of a widely established process hypothesis to generate shallow cavities by salt subrosion, which subsequently collapse to sinkholes at the surface. Results of the initial survey carried out in 2013 highlighted a new process hypothesis of subsurface mass transport by Dead Sea mud mobilization enclosed in the alluvial fan, so that an extended survey was undertaken in 2014. This, indeed, confirmed that there are no reflection seismic signal responses that would be expected to occur in the presence of a massive salt layer. Since evaluation of both hypothesis by new drilling could not be carried out due to safety reasons and permissions, it remained unclear which hypothesis is valid for the investigation site. However, we combined the 2013 and 2014 reflection seismic profiles and the

  7. A Model to Predicting the Evolution of Suspended Sediment Concentration Profiles and Bedforms Before, During, and After Storm Events

    NASA Astrophysics Data System (ADS)

    Nelson, T. R.; Voulgaris, G.; Warner, J. C.

    2008-12-01

    Ripples are dominant and vital features on the seabed. Previous studies have focused on equilibrium ripple characteristics. However, relict ripples generally dominate the seabed temporally. These ripples can retain the same dimensions of the active ripples or adjust due to brief periods of sediment mobility. This presentation focuses on the characterization and prediction of the temporal and spatial evolution of continuous and discontinuous 2D and 3D ripples during various degrees of bed mobilization and suspended sediment resuspension. Bedforms on the inner shelf were observed (October 2003 - March 2004) off Long Bay, South Carolina. During this period, waves propagated to the northwest with an average significant wave height of 0.57 m and period of 6.4 s. The site was composed of fine-medium sand (D50=177 microns). The geometry of the bedforms (wavelength, orientation, and plan-view shape) was determined using spectral and visual analysis of sonar images produced by an Imagenex rotating sonar system. Suspended sediment profiles were measured by an Aquatec Aquascat Acoustic Backscatter Sensor. This presentation focuses on the interaction of bedforms, suspended sediment concentration, and wave- current interactions. The bedform parameters were compared with a new 2D time dependent model to predict the evolution of the 2D ripple spectra under changing wave-current forcing and direction. Preliminary indications show the 2D model improves the prediction and evolution of the ripple plan view shape over current 1D models. The 2D model shows the development of ripples from flat bed, appearance of cross ripples and the evolution to a new dominant ripple orientation and wavelength, as well as modification due to slight changes in hydrodynamic forcing. Further investigation characterizes the behavior of suspended sediment profile models against the measured profile above linear transition, irregular, and cross ripples. The evolutionary steps of the bedform and suspended

  8. Interspecies comparison of chlorinated contaminant concentrations and profiles in wild terrestrial mammals from northwest Poland.

    PubMed

    Tomza-Marciniak, Agnieszka; Marciniak, Andrzej; Pilarczyk, Bogumiła; Prokulewicz, Agnieszka; Bąkowska, Małgorzata

    2014-05-01

    The aim of this study was to determine residual polychlorinated biphenyls (PCBs) and organochlorine pesticides in the adipose tissue of wild terrestrial mammals coming from the same area in northwest Poland and to compare the organochlorine content and profile between species. The study was performed on five mammalian species, including omnivores (badger, wild boar, raccoon dog) and herbivores (roe deer, red deer). The obtained results show that the levels of residues of most of the analyzed compounds were greater in omnivorous mammals than herbivorous mammals. We found differences in the pattern of accumulation of organochlorines. In the raccoon dog organochlorines accumulated in the following descending order: DDTs > PCBs > HCHs > endrin > dieldrin; in the badger, wild boar, and roe deer, the order was as follows: DDTs > HCHs > PCBs > endrin > dieldrin; and in red deer, the order was as follows: HCHs > DDTs > PCBs > endrin > dieldrin. PCB 153 was dominant in herbivores and in the wild boar, whereas in the raccoon dog it was lower than PCB 138 and in badger lower than PCB 180. These differences in the tested species may reflect differences in metabolic capacity and/or feeding habits and an uneven distribution of organochlorines in the area where the animals lived. Maximum residue levels (MRLs) were exceeded in single samples from animals whose meat and fat can be consumed by humans. The greatest number of cases where MRLs were exceeded was observed in the adipose tissue of the badger (HCHs, DDTs, endrin, non-dioxin-like PCBs) and the fewest in the adipose tissue of roe deer (only lindane). PMID:24430167

  9. A Comparison of HCHO and CHOCHO Concentrations and Profiles in Three North American Forests

    NASA Astrophysics Data System (ADS)

    Galloway, M. M.; Digangi, J. P.; Henry, S. B.; Kammrath, A.; Thurlow, M. E.; O'Brien, A.; Boyle, E.; Keutsch, F. N.; Bearpex Science Team; Cabinex Science Team; Beachon-Rocs Science Team

    2010-12-01

    The oxidation of volatile organic compounds (VOCs) is central to the production of tropospheric ozone smog and the formation of secondary organic aerosol (SOA). The oxidation of biogenic VOCs (BVOCs), such as isoprene and terpenes emitted from forests, can result in elevated ozone and aerosol concentrations in rural areas away from urban pollution. Formaldehyde (HCHO) and glyoxal (GLY) are among the most ubiquitous VOC oxidation intermediates and are therefore important tracers of VOC oxidation. It has also been suggested that glyoxal may be a significant source of SOA (Volkamer, 2005). Together, these compounds provide insight into both the rate of VOC oxidation and source of VOC precursors in an environment. Both compounds were measured simultaneously during three pristine forest field campaigns (BEARPEX 2009, CABINEX 2009, and BEACHON-ROCS 2010). We present a comparison of our results from these campaigns, focusing on HCHO/GLY ratios and correlations of HCHO and GLY with other species.

  10. The use of tunnel concentration profile data to determine the ratio of NO2/NOx directly emitted from vehicles

    NASA Astrophysics Data System (ADS)

    Yao, X.; Lau, N. T.; Chan, C. K.; Fang, M.

    2005-12-01

    Recently, it is reported that primary vehicular NO2/NOx ratio to be 10-30% and primary vehicular NO2 has raised much interest and concern in the control of NO2 in urban areas. In this study, primary vehicular NO2/NOx ratio in Hong Kong was investigated based on intensive long tunnel (3.7-4 km in length) experiments where concentration profiles of air pollutants along the entire lengths of the tunnels were obtained. Long tunnels were selected because of the inherent low O3 concentrations in the partially enclosed environment. In addition the concentrations of pollutants from vehicles are high. Thus, the NO2 measured inside long tunnels would be more representative of the primary NO2 emitted by vehicles and contribution due to atmospheric transformation would be limited. This dataset was supported by a long-term on-road air quality dataset (June 2002-August 2003). Both datasets were obtained using the Mobile Real-time Air Monitoring Platform (MAP). The primary on-road vehicular NO2/NOx ratio was less than 2%, detected in the mid sections of tunnels investigated, where O3 concentration was at a minimum. In sections of the tunnels (entrance and exit) where O3 concentrations were relatively high, the NO2/NOx ratio could be as high as 19%. Long-term (annual average) on-road air quality data in open air yielded NO2/NOx ratios up to 28%. Thus, it is apparent that directly emitted NO2 from vehicles is not significant in atmospheric NO2 concentration. A simple model was used to segregate the contribution of background NO2 and transformed NO2 measured in vehicle plumes.

  11. The effects of vehicle emissions and nucleation events on vertical particle concentration profiles around urban office buildings

    NASA Astrophysics Data System (ADS)

    Quang, T. N.; He, C.; Morawska, L.; Knibbs, L. D.; Falk, M.

    2012-01-01

    Despite its role in determining both indoor and outdoor human exposure to anthropogenic particles, there is limited information describing vertical profiles of particle concentrations in urban environments, especially for ultrafine particles. Furthermore, the results of the few studies performed have been inconsistent. As such this study aimed to assess the influence of vehicle emissions and nucleation formation on particle concentrations (PN and PM2.5) at different heights around three urban office buildings located next to busy roads in Brisbane, Australia, and place these results in the broader context of the existing literature. Two sets of instruments were used to simultaneously measure PN size distribution, PN and PM2.5 concentrations, respectively, for up to three weeks each at three office buildings. The results showed that both PN and PM2.5 concentrations around building envelope were influenced by vehicle emissions and new particle formation, and that they exhibited variability across the three different office buildings. During the nucleation event, PN concentrations increased (21-46%), while PM2.5 concentrations decreased (36-52%) with height at all three buildings. This study has shown an underappreciated role of nucleation in producing particles that can affect large numbers of people, due to the high density and occupancy of urban office buildings and the fact that the vast majority of people's time is spent indoors. These findings highlight important new information related to the previously overlooked role of particle formation in the urban atmosphere and its potential effects on selection of air intake locations and appropriate filter types when designing or upgrading mechanical ventilation systems in urban office buildings. The results also serve to better define particle behaviour and variability around building envelopes, which has implications for studies of both human exposure and particle dynamics.

  12. The developmental long trace profiler (DLTP) optimized for metrology of side-facing optics at the ALS

    NASA Astrophysics Data System (ADS)

    Lacey, Ian; Artemiev, Nikolay A.; Domning, Edward E.; McKinney, Wayne R.; Morrison, Gregory Y.; Morton, Simon A.; Smith, Brian V.; Yashchuk, Valeriy V.

    2014-09-01

    The autocollimator and moveable pentaprism based DLTP [NIM A 616 (2010) 212-223], a low-budget, NOM-like profiler at the Advanced Light Source (ALS), has been upgraded to provide fast, highly accurate surface slope metrology for long, side-facing, x-ray optics. This instrument arrangement decreases sensitivity to environmental conditions and removes the gravity effect on mirror shape. We provide design details of an affordable base tool, including clean-room environmental arrangements in the new ALS X-ray Optics Laboratory with advanced temperature stabilization and turbulence reduction, that yield measurements in under 8 hours with accuracy better than 30 nanoradians (rms) for super polished,190 mm flat optics, limited mainly by residual temporal instability of the experimental set-up. The upgraded DLTP has been calibrated for highly curved x-ray optics, allowing same day measurements of a 15 m ROC sphere with accuracy of better than 100 nanoradians (rms). The developed calibration procedure is discussed in detail. We propose this specific 15 m ROC sphere for use as a round-robin calibration test optic.

  13. Improved n-channel Ge gate stack performance using HfAlO high-k dielectric for various Al concentrations

    NASA Astrophysics Data System (ADS)

    Kothari, Shraddha; Joishi, Chandan; Ghosh, Sayantan; Biswas, Dipankar; Vaidya, Dhirendra; Ganguly, Swaroop; Lodha, Saurabh

    2016-07-01

    We demonstrate improved Ge n-channel gate stack performance versus HfO2 using HfAlO high-k dielectric for a wide (1.5–33%) range of Al% and post-high-k-deposition annealing (PDA) at 400 °C. Addition of Al to HfO2 is shown to mitigate degradation of the GeO2/Ge interface during PDA. HfAlO stacks with an equivalent oxide thickness (EOT) of 8 nm and large Al% exhibit improved transistor mobility (1.8 times higher) and midgap D it (2 times lower), whereas thin (1.9 nm) EOT HfAlO stacks show reduced gate leakage J g (by 10 times) and D it (by 1.5 times) and 1.6 times higher mobility for Al% as low as 1.5% at matched EOT.

  14. The Potential of The Synergy of Sunphotometer and Lidar Data to Validate Vertical Profiles of The Aerosol Mass Concentration Estimated by An Air Quality Model

    NASA Astrophysics Data System (ADS)

    Siomos, N.; Filioglou, M.; Poupkou, A.; Liora, N.; Dimopoulos, S.; Melas, D.; Chaikovsky, A.; Balis, D. S.

    2016-06-01

    Vertical profiles of the aerosol mass concentration derived by the Lidar/Radiometer Inversion Code (LIRIC), that uses combined sunphotometer and lidar data, were used in order to validate the aerosol mass concentration profiles estimated by the air quality model CAMx. Lidar and CIMEL measurements performed at the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki, Greece (40.5N, 22.9E) from the period 2013-2014 were used in this study.

  15. Concentration profiles and spatial distribution of perfluoroalkyl substances in an industrial center with condensed fluorochemical facilities.

    PubMed

    Shan, Guoqiang; Wei, Mingcui; Zhu, Lingyan; Liu, Zhengtao; Zhang, Yahui

    2014-08-15

    Jiangsu Hi-tech Fluorochemical Industry Park, China, is one of the largest fluorochemical industry centers in Asia and could be a point source of polyfluoroalkyl substances (PFASs) to the surrounding environment. Besides water, sediment and soil samples, tree leaves and bark were also collected to monitor airborne PFASs around the facilities. Perfluorooctanoic acid and short-chain perfluorocarboxylates including perfluorohexanoic acid and perfluoropentanoic acid were found predominantly in all the samples. The target ∑PFASs were distributed in the dissolved phase with a proportion of 96.5±2.9%. High concentrations of ∑PFASs (up to 12,700 ng/L in surface water) were found at sites near and within the wastewater treatment plant and the facilities. The ∑PFASs in the sediment/sludge were in the range of 3.33-324 ng/g dw. For the first time, tree samples were used for bio-monitoring airborne PFASs in the environment. The ∑PFASs in the tree leaf and bark samples were in the range of 10.0-276 and 6.76-120 ng/g dw, respectively. The spatial distribution of ∑PFASs in the tree leaves suggested that airborne PFASs could be transported from the center to the surrounding environment by prevailing wind. PMID:24867700

  16. Direct measurement of local dissolved oxygen concentration spatial profiles in a cell culture environment.

    PubMed

    Kagawa, Yuki; Matsuura, Katsuhisa; Shimizu, Tatsuya; Tsuneda, Satoshi

    2015-06-01

    Controlling local dissolved oxygen concentration (DO) in media is critical for cell or tissue cultures. Various biomaterials and culture methods have been developed to modulate DO. Direct measurement of local DO in cultures has not been validated as a method to test DO modulation. In the present study we developed a DO measurement system equipped with a Clark-type oxygen microelectrode manipulated with 1 μm precision in three-dimensional space to explore potential applications for tissue engineering. By determining the microelectrode tip position precisely against the bottom plane of culture dishes with rat or human cardiac cells in static monolayer culture, we successfully obtained spatial distributions of DO in the medium. Theoretical quantitative predictions fit the obtained data well. Based on analyses of the variance between samples, we found the data reflected "local" oxygen consumption in the vicinity of the microelectrode and the detection of temporal changes in oxygen consumption rates of cultured cells was limited by the diffusion rate of oxygen in the medium. This oxygen measuring system monitors local oxygen consumption and production with high spatial resolution, and can potentially be used with recently developed oxygen modulating biomaterials to design microenvironments and non-invasively monitor local DO dynamics during culture. PMID:25565074

  17. Rheological profiling of organogels prepared at critical gelling concentrations of natural waxes in a triacylglycerol solvent.

    PubMed

    Patel, Ashok R; Babaahmadi, Mehrnoosh; Lesaffer, Ans; Dewettinck, Koen

    2015-05-20

    The aim of this study was to use a detailed rheological characterization to gain new insights into the gelation behavior of natural waxes. To make a comprehensive case, six natural waxes (differing in the relative proportion of chemical components: hydrocarbons, fatty alcohols, fatty acids, and wax esters) were selected as organogelators to gel high-oleic sunflower oil. Flow and dynamic rheological properties of organogels prepared at critical gelling concentrations (Cg) of waxes were studied and compared using drag (stress ramp and steady flow) and oscillatory shear (stress and frequency sweeps) tests. Although, none of the organogels satisfied the rheological definition of a "strong gel" (G″/G' (ω) ≤ 0.1), on comparing the samples, the strongest gel (highest critical stress and dynamic, apparent, and static yield stresses) was obtained not with wax containing the highest proportion of wax esters alone (sunflower wax, SFW) but with wax containing wax esters along with a higher proportion of fatty alcohols (carnauba wax, CRW) although at a comparatively higher Cg (4%wt for latter compared to 0.5%wt for former). As expected, gel formation by waxes containing a high proportion of lower melting fatty acids (berry, BW, and fruit wax, FW) required a comparatively higher Cg (6 and 7%wt, respectively), and in addition, these gels showed the lowest values for plateau elastic modulus (G'LVR) and a prominent crossover point at higher frequency. The gelation temperatures (TG'=G″) for all the studied gels were lower than room temperature, except for SFW and CRW. The yielding-type behavior of gels was evident, with most gels showing strong shear sensitivity and a weak thixotropic recovery. The rheological behavior was combined with the results of thermal analysis and microstructure studies (optical, polarized, and cryo-scanning electron microscopy) to explain the gelation properties of these waxes. PMID:25932656

  18. Progesterone alters global transcription profiles at environmental concentrations in brain and ovary of female zebrafish (Danio rerio).

    PubMed

    Zucchi, Sara; Castiglioni, Sara; Fent, Karl

    2013-01-01

    Progesterone (P4) is a natural steroid hormone excreted by humans and animals. Noncomplete degradation in treatment plants result in levels in the ng/L range in surface waters. Very little is known of the effects on fish at such concentrations. Here we determine the global expression profile in the brain and ovary of female zebrafish exposed for 14 days to 3.5, 33 and 306 ng/L P4 to elucidate molecular effects. For validation selected transcripts were determined by RT-qPCR. In the brain, 54 and 255 transcripts were altered at 3.5 and 306 ng/L, respectively. Genes related to circadian rhythm (nr1d2b, per1b), cell cycle and reproduction (cdc20, ccnb1) were down-regulated. In the ovary, transcriptional changes occurred in 200, 84 and 196 genes at 3.5, 33 and 306 ng/L, respectively. The genes belong to different pathways including cardiac hypertrophy, cell cycle and its regulation. P4 slightly influenced oocyte maturation as revealed by histology of the ovaries. In the liver, vtg1 was down-regulated at all concentrations and VTG protein at 306 ng/L in the blood. The data show molecular effects and the modes of action of P4 at environmental concentrations. Ultimately they may translate to adverse effects on reproduction. PMID:24083816

  19. Effects of Eu concentration control on crystal growth and scintillation properties for Eu:LiSrAlF6 crystals

    NASA Astrophysics Data System (ADS)

    Suzuki, S.; Yokota, Y.; Yamaji, A.; Kurosawa, S.; Kamada, K.; Yoshikawa, A.

    2014-10-01

    Eu doped LiSrAlF6 (Eu:LiSAF) crystals with various Eu concentrations were grown by a micro-pulling-down (μ-PD) method and the effects of Eu concentration control on crystal growth and scintillation properties for Eu:LiSAF crystals were investigated as a neutron scintillator. As-grown Eu0.3%:LiSAF crystal had no visible inclusion while milky parts were observed in the crystals with higher Eu contents. The secondary phases with the chemical composition of EuF2 or EuF3 in the Eu:LiSAF matrix were observed for the crystals with high Eu contents while the secondary phase couldn’t be observed in the powder XRD patterns. In the radioluminescence spectra of Eu:LiSAF crystals under α-ray irradiation, emission peaks around 375 nm originated from 5d-4f transition of Eu2+ ion were observed. The light yields systematically increased with an increase of actual Eu contents in the crystals and the decay times were 1490-1620 ns.

  20. Conduction mechanisms in concentrated LiI-polyethylene oxide-Al{sub 2}O{sub 3}-based solid electrolytes

    SciTech Connect

    Golodnitsky, D.; Ardel, G.; Strauss, E.; Peled, E.; Lareah, Y.; Rosenberg, Y.

    1997-10-01

    The ionic conductivity of concentrated LiI-polyethylene oxide P(EO){sub n} high surface area oxide composite polymer electrolytes has been investigated. Two different Arrhenius dependences for concentrated composite polymer electrolytes (CPEs) have been identified. The first one is characterized by an inflection point at about 80 C, and the second, by a conductivity jump. The authors have suggested that in CPEs, where 3concentrated CPEs, which are defined as CSEs, is interfacial conduction. Differential scanning calorimetry, scanning electron microscopy, and X-ray data, presented here, are evidence supporting the view. The effects of several parameters including type and content of oxide matrix, Li salt to ethylene oxide ratio, copolymers, and solvents on polymer electrolyte conductivity (especially at T >T{sub k}orT{sub jump}) and on Ea have been studied (T{sub jump}=temperature of the conductivity jump). The addition of small quantities of ethylene carbonate, poly(methyl methacrylate), and polyacrylonitrile were found to be beneficial while poly(methyl acrylate), poly(butyl acrylate), and poly(vinylidene fluoride) additions made the polymer electrolyte stiffer and less conductive. MgO, Al{sub 2}O{sub 3}, and potassium aluminosilicate muscovite mica based CSEs have similar conductivity. Results clearly demonstrated the depression of CPE crystallinity by addition of fine Al{sub 2}O{sub 3} powder, ethylene carbonate, and poly(ethylene glycol) dimethyl ether, in agreement with the conductivity enhancement of the CPE.

  1. Induced Changes in the Amino Acid Profile of Biomphalaria alexandrina Molluscan Host to Schistosoma mansoni Using Sublethal Concentrations of Selected Plant Molluscicides

    NASA Astrophysics Data System (ADS)

    Sanad Soliman, Mahmoud; El-Ansary, Afaf

    Amino acid profiles of control and Solanum nigrum, Ambrosia maritima, Thymelaea hirsute, Sinapis arvensis, Peganum haramala and Callistemon lanceolatus-treated Biomphalaria alexandrina snails were investigated in a trial to correlate the amino acid profile of treated snails to their previously reported molluscicidal and biological effects. Amino acid profiles of the snails were greatly manipulated with the treatment of dry powdered sublethal concentrations of the six studied plant molluscicides. The disturbed amino acid profiles of treated snails were discussed in relation to the decrease in snail's egg laying capacity, reduction of their compatibility for the development of the schistosome larvae and cercarial penetration of mammalian skin.

  2. Concentrations of synthetic musk compounds in personal care and sanitation products and human exposure profiles through dermal application.

    PubMed

    Roosens, Laurence; Covaci, Adrian; Neels, Hugo

    2007-11-01

    Synthetic musks, such as 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN) and 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-gamma-2-benzopyran (HHCB), musk ketone (MK) and musk xylene (MX), are used as an alternative for natural musk. Due to their widespread use, these synthetic compounds turned up in different environmental compartments, such as wastewater, human and animal tissues. Yet, little is known about their distribution and occurrence in personal care and household products, information needed in order to evaluate the different human exposure routes. This paper gives an overview of the synthetic musk levels in six different product categories: body lotions, perfumes, deodorants, hair care products, shower products and sanitation products. Especially body lotions, perfumes and deodorants contained high levels of synthetic musks. Maximum concentrations of HHCB, AHTN, MX and MK were 22 mg g(-1), 8 mg g(-1), 26 microg g(-1) and 0.5 microg g(-1), respectively. By combining these results with the average usage of consumer products, low-, medium- and high-exposure profiles through dermal application could be estimated. HHCB was the highest contributor to the total amount of synthetic musks in every exposure profile (18-23 700 microg d(-1)). Exposure to MK and MX did not increase substantially (10-20-fold) between low- and high-exposure profiles, indicating that these compounds cover a less broad range. In comparison, exposure to HHCB and AHTN increased up to 10 000 fold between low- and high-exposure. PMID:17631381

  3. Fluorescence enhancement of dyes embedded in nanoparticles of Lu, Eu, Al, and Sc diketonates of different composition and concentration

    NASA Astrophysics Data System (ADS)

    Mironov, L. Yu.; Sveshnikova, E. B.; Ermolaev, V. L.

    2014-12-01

    We have studied the effect of central ions (Lu(III), Eu(III), Sc(III), and Al(III)), organic ligands (2-naphthoyltrifluoroacetone (NTA) and p-phenylbenzoyltrifluoroacetone (PhBTA)), and their concentration in a water-alcohol solution on the fluorescence of β-diketonate complexes formed and nanoparticles (NPs) generated by the self-assembly of these complexes. The fluorescence quenching of ligands of the complexes of nanoparticles because of the introduction of molecules of dyes, such as Nile Blue (NB), Lissamine Rhodamine RB-200 (RB), and Crystal Violet (CV), in these nanoparticles is investigated, and the NP-sensitization of the fluorescence of these dyes is explored. The dependence of the intensity of the NP-sensitized fluorescence of NB on its concentration in nanoparticles consisting of complexes that differ in composition and concentration is studied. By analyzing this dependence for the nanoparticles consisting of Sc(NTA)3, the size of the studied nanoparticles is evaluated. It is shown that the nature of this dependence is determined by a competition of two processes: the migration of the excitation energy over complexes to dyes and the migration of the excitation energy of dyes to impurities or dimer of dyes. The size of nanoparticles is compared to the estimated values of the exciton diffusion length and the critical radius of energy transfer from complexes to NB. An energy transfer of close to 100% from the nanoparticles formed of 10 μM of Sc(NTA)3 to 50 nM of NB molecules embedded therein is observed. The introduction of NB molecules into nanoparticles leads to a 200-fold increase in fluorescence intensity compared to their direct excitation in solution.

  4. Seasonal dynamics of soil CO2 efflux and soil profile CO2 concentrations in arboretum of Moscow botanical garden

    NASA Astrophysics Data System (ADS)

    Goncharova, Olga; Udovenko, Maria; Matyshak, Georgy

    2016-04-01

    To analyse and predict recent and future climate change on a global scale exchange processes of greenhouse gases - primarily carbon dioxide - over various ecosystems are of rising interest. In order to upscale land-use dependent sources and sinks of CO2, knowledge of the local variability of carbon fluxes is needed. Among terrestrial ecosystems, urban areas play an important role because most of anthropogenic emissions of carbon dioxide originate from these areas. On the other hand, urban soils have the potential to store large amounts of soil organic carbon and, thus, contribute to mitigating increases in atmospheric CO2 concentrations. Research objectives: 1) estimate the seasonal dynamics of carbon dioxide production (emission - closed chamber technique and profile concentration - soil air sampling tubes method) by soils of Moscow State University Botanical Garden Arboretum planted with Picea obovata and Pinus sylvestris, 1) identification the factors that control CO2 production. The study was conducted with 1-2 weeks intervals between October 2013 and November 2015 at two sites. Carbon dioxide soil surface efflux during the year ranged from 0 to 800 mgCO2/(m2hr). Efflux values above 0 mgCO2/(m2hr) was observed during the all cold period except for only 3 weeks. Soil CO2 concentration ranged from 1600-3000 ppm in upper 10-cm layer to 10000-40000 ppm at a depth of 60 cm. The maximum concentrations of CO2 were recorded in late winter and late summer. We associate it with high biological activity (both heterotrophic and autotrophic) during the summer, and with physical gas jamming in the winter. The high value of annual CO2 production of the studied soils is caused by high organic matter content, slightly alkaline reaction, good structure and texture of urban soils. Differences in soil CO2 production by spruce and pine urban forest soils (in the pine forest 1.5-2.0 times higher) are caused by urban soil profiles construction, but not temperature regimes. Seasonal

  5. Admittance–voltage profiling of Al{sub x}Ga{sub 1−x}N/GaN heterostructures: Frequency dependence of capacitance and conductance

    SciTech Connect

    Köhler, K.; Pletschen, W.; Godejohann, B.; Müller, S.; Menner, H. P.; Ambacher, O.

    2015-11-28

    Admittance–voltage profiling of Al{sub x}Ga{sub 1−x}N/GaN heterostructures was used to determine the frequency dependent capacitance and conductance of FET devices in the frequency range from 50 Hz to 1 MHz. The nominally undoped low pressure metal-organic vapor-phase epitaxy structures were grown with an Al-content of 30%. An additional 1 nm thick AlN interlayer was placed in one structure before the Al{sub 0.3}Ga{sub 0.7}N layer growth. For frequencies below 10{sup 8} Hz it is convenient to use equivalent circuits to represent electric or dielectric properties of a material, a method widely used, for example, in impedance spectroscopy. We want to emphasize the relation between frequency dependent admittance–voltage profiling and the corresponding equivalent circuits to the complex dielectric function. Debye and Drude models are used for the description of the frequency dependent admittance profiles in a range of depletion onset of the two-dimensional electron gas. Capacitance- and conductance-frequency profiles are fitted in the entire measured range by combining both models. Based on our results, we see contributions to the two-dimensional electron gas for our samples from surface states (80%) as well as from background doping in the Al{sub 0.3}Ga{sub 0.7}N barriers (20%). The specific resistance of the layers below the gate is above 10{sup 5} Ω cm for both samples and increases with increasing negative bias, i.e., the layers below the gate are essentially depleted. We propose that the resistance due to free charge carriers, determined by the Drude model, is located between gate and drain and, because of the AlN interlayer, the resistance is lowered by a factor of about 30 if compared to the sample without an AlN layer.

  6. Mathematical analysis of mural thrombogenesis. Concentration profiles of platelet-activating agents and effects of viscous shear flow.

    PubMed Central

    Folie, B J; McIntire, L V

    1989-01-01

    The concentration profiles of adenosine diphosphate (ADP), thromboxane A2 (TxA2), thrombin, and von Willebrand factor (vWF) released extracellularly from the platelet granules or produced metabolically on the platelet membrane during thrombus growth, were estimated using finite element simulation of blood flow over model thrombi of various shapes and dimensions. The wall fluxes of these platelet-activating agents were estimated for each model thrombus at three different wall shear rates (100 s-1, 800 s-1, and 1,500 s-1), employing experimental data on thrombus growth rates and sizes. For that purpose, whole human blood was perfused in a parallel-plate flow chamber coated with type l fibrillar human collagen, and the kinetic data collected and analyzed by an EPl-fluorescence video microscopy system and a digital image processor. It was found that thrombin concentrations were large enough to cause irreversible platelet aggregation. Although heparin significantly accelerated thrombin inhibition by antithrombin lll, the remaining thrombin levels were still significantly above the minimum threshold required for irreversible platelet aggregation. While ADP concentrations were large enough to cause irreversible platelet aggregation at low shear rates and for small aggregate sizes, TxA2 concentrations were only sufficient to induce platelet shape change over the entire range of wall shear rates and thrombi dimensions studied. Our results also indicated that the local concentration of vWF multimers released from the platelet alpha-granules could be sufficient to modulate platelet aggregation at low and intermediate wall shear rates (less than 1,000 s-1). The sizes of standing vortices formed adjacent to a growing aggregate and the embolizing stresses and the torque, acting at the aggregate surface, were also estimated in this simulation. It was found that standing vortices developed on both sides of the thrombus even at low wall shear rates. Their sizes increased with

  7. Maternal-to-fetal transfer and concentration profiles of PCB congeners for Steller sea lions (Eumetopias jubatus) from Hokkaido, Japan.

    PubMed

    Kubo, Keiko; Yamaguchi, Katsuyuki; Ishinazaka, Tsuyoshi; Yamada, Wakana; Hattori, Kaoru; Tanaka, Shunitz

    2014-01-15

    The concentrations of PCB congeners in the blubber and liver of mother Steller sea lions (Eumetopias jubatus; SSLs) and their fetuses from the coast of Hokkaido, Japan in 2008, 2010 and 2012 were analyzed by HRGC-HRMS, in order to elucidate PCB congener profiles and maternal-to-fetal transfer of PCBs in SSLs. ΣPCBs in the fetuses were 1400 ± 660 (the mean ± SD) ng/g-fat in the blubber and 570 ± 320 ng/g-fat in the liver, respectively. There was a concern that SSLs had been contaminated by PCBs during the fetal period. The concentrations of the major congeners in the blubber and liver were a correlation between the fetus and mother (blubber: r=0.9934, liver: r=0.9160; P ≦ 0.05). The results indicated that PCBs in the fetuses came from the mothers. #177 and #199 showed no correlations between the fetus and the mother in the blubber and liver. This indicated a selective capture by some natural protector such as the placenta. PMID:24269191

  8. Serum Adiponectin and Leptin Concentrations in Relation to Body Fat Distribution, Hematological Indices and Lipid Profile in Humans

    PubMed Central

    Lubkowska, Anna; Radecka, Aleksandra; Bryczkowska, Iwona; Rotter, Iwona; Laszczyńska, Maria; Dudzińska, Wioleta

    2015-01-01

    The purpose of the study was to evaluate the relationship between serum adiponectin and leptin concentrations and body composition, hematological indices and lipid profile parameters in adults. The study involved 95 volunteers (BMI from 23.3 to 53 kg/m2). Anthropometric parameters were measured: body weight and height, waist and hip circumference, waist-to-hip ratio, body fat mass (BMF), subcutaneous and visceral fat mass (SFM, VFM), lean body mass (LBM), skeletal muscle mass (SMM). In serum we determined adiponectin and leptin concentrations, extracellular hemoglobin, total bilirubin, as well as lipid metabolism (TCh, HDL-Ch, LDL-Ch, TG). Mean adipokine levels were significantly higher in women (p ≤ 0.01), adiponectin significantly negatively correlated with body height and weight, systolic blood pressure and absolute LBM and SMM values. The same relation was observed for erythroid system indicators and lipid indicators. A positive correlation was exceptionally found between adiponectin and HDL-Ch. LEP negatively correlated with some percentage rates (%LBM, %SMM). Only in women, we observed a positive correlation between LEP and body weight, BMI and WHR. Studies on ADPN and the ADPN/LEP ratio as a valuable complementary diagnostic element in the prediction and prevention of cardiovascular diseases need to be continued. PMID:26389928

  9. Relating Aerosol Profile and Column Measurements to Surface Concentrations: What Have We Learned from Discover-AQ?

    NASA Astrophysics Data System (ADS)

    Hoff, R. M.

    2014-12-01

    One research goal of the Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) mission was to determine sufficient column profile measurements to relate column integrated quantities such as Aerosol Optical Depth to surface concentrations. I will review the relationship between AOD and PM2.5 at the surface. DISCOVER-AQ in Baltimore, the San Joaquin Valley, Houston and Denver revealed quite different conditions for determining this relationship. In each case, the surface reflectivity made determination of aerosol optical depth challenging, but upward looking columns of aerosol optical depth from sunphotometers provided confirmation of the AOD results from space. In Baltimore, AOD fields reflected PM2.5 concentrations well. In California, however, the low boundary layer heights and dominance of nitrate and organic aerosols made the AOD fields less predictive of PM2.5. In California and Colorado, hydration of the aerosol varied dramatically with aerosol type (especially smoke and dust) and revealed that without an understanding of the degree of aerosol hydration with aerosol composition, the relationship between AOD and PM2.5 will continue to be a challenge. Model predictions in the Baltimore-Washington study are relatively disappointing in helping define the needed physics between the optical and microphysical properties. An overview of the measurements from DISCOVER-AQ which will help define the needed information in a more general case in the future will be given.

  10. Serum Adiponectin and Leptin Concentrations in Relation to Body Fat Distribution, Hematological Indices and Lipid Profile in Humans.

    PubMed

    Lubkowska, Anna; Radecka, Aleksandra; Bryczkowska, Iwona; Rotter, Iwona; Laszczyńska, Maria; Dudzińska, Wioleta

    2015-09-01

    The purpose of the study was to evaluate the relationship between serum adiponectin and leptin concentrations and body composition, hematological indices and lipid profile parameters in adults. The study involved 95 volunteers (BMI from 23.3 to 53 kg/m²). Anthropometric parameters were measured: body weight and height, waist and hip circumference, waist-to-hip ratio, body fat mass (BMF), subcutaneous and visceral fat mass (SFM, VFM), lean body mass (LBM), skeletal muscle mass (SMM). In serum we determined adiponectin and leptin concentrations, extracellular hemoglobin, total bilirubin, as well as lipid metabolism (TCh, HDL-Ch, LDL-Ch, TG). Mean adipokine levels were significantly higher in women (p ≤ 0.01), adiponectin significantly negatively correlated with body height and weight, systolic blood pressure and absolute LBM and SMM values. The same relation was observed for erythroid system indicators and lipid indicators. A positive correlation was exceptionally found between adiponectin and HDL-Ch. LEP negatively correlated with some percentage rates (%LBM, %SMM). Only in women, we observed a positive correlation between LEP and body weight, BMI and WHR. Studies on ADPN and the ADPN/LEP ratio as a valuable complementary diagnostic element in the prediction and prevention of cardiovascular diseases need to be continued. PMID:26389928

  11. Effects of dietary gossypol concentration on growth performance, blood profiles, and hepatic histopathology in meat ducks1

    PubMed Central

    Zeng, Q. F.; Yang, G. L.; Liu, G. N.; Wang, J. P.; Bai, S. P.; Ding, X. M.; Luo, Y. H.; Zhang, K. Y.

    2014-01-01

    The objective of this study was to determine the effects of gossypol from cottonseed meal (CSM) on growth performance, blood biochemical profiles, and liver histopathology of ducks. A total of 900 1-d-old ducks were randomly allocated to 5 treatments with 12 pens/treatment and 15 ducks/pen. The 5 experimental diets were formulated in such a way that 0% (a corn-soybean meal basal diet, diet 1), 25% (diet 2), 50% (diet 3), 75% (diet 4), and 100% (diet 5) of protein from soybean meal were replaced with that from CSM. All diets were formulated on a digestible amino acid basis. The experiment included 2 phases, the starter phase (1 to 3 wk) where the test diets contained graded levels of CSM and the growth phase (4 to 5 wk) where birds were fed a corn-soybean basal diet to examine the recovery of ducks after CSM withdrawal. Dietary CSM and gossypol linearly (P < 0.01) and quadratically (P < 0.01) decreased ADG and ADFI during d 1 to 14. The threshold of daily total gossypol (TG) and free gossypol (FG) intake based on ADG on d 1 to 7 and d 7 to 14 were 32.20 and 2.64 mg/d, and 92.12 and 9.62 mg/d, respectively. Serum alanine aminotransferase increased (P < 0.05) linearly with increasing level of gossypol in the diets (d 7), whereas aspartate aminotransferase increased (P < 0.05) linearly and quadratically (d 14). Serum albumin concentration decreased (P < 0.05) quadratically with increasing dietary CSM concentrations on d 21. The degree of damage to the liver increased markedly with increasing dietary CSM and gossypol content and the length of CSM and gossypol intake. On d 35, there was no difference on BW and blood profiles of ducks among all treatments. These results suggest that meat ducks’ dietary TG and FG concentration should be lower than 928.9 and 77.2 mg/kg, respectively, during d 1 to 21 of age and that a 2-wk withdrawal of diets containing gossypol should be considered. PMID:24902707

  12. Reconstructed chloride concentration profiles below the seabed in Hong Kong (China) and their implications for offshore groundwater resources

    NASA Astrophysics Data System (ADS)

    Jiao, Jiu Jimmy; Shi, Lei; Kuang, Xingxing; Lee, Chun Ming; Yim, Wyss W.-S.; Yang, Shouye

    2015-03-01

    Offshore hydrogeology has been much less studied compared to onshore hydrogeology. The marine Quaternary system in Hong Kong (China) consists of interlayers of aquitards and aquifers and was part of the Pearl River Delta when the sea level was low before the Holocene. Core samples from six offshore boreholes were collected to measure the chloride concentration in the system by adding deionized water. A method was proposed to convert the sediment chloride into that of the original pore water. A one-dimensional sedimentation-transport model was developed to simulate the historical conservative transport of the reconstructed pore-water chloride. The model integrates present knowledge of stratigraphy and the historical evolution of the geological system. The chloride concentration profiles show that the chloride decreases from an average of 13,800 mg/L in the first marine unit to an average of 5,620 mg/L in the first aquifer. At the bottom of one borehole, the concentration is only 1,420 mg/L. The numerical model shows that the vertical chloride distribution is due to diffusion-controlled downward migration of seawater. The second marine unit obstructs the downward migration, indicating its low permeability and good aquitard integrity. The relatively fresh or brackish water in deep aquifers protected by the aquitard has the potential to be used as drinking water following some treatment, or at least as raw water with much cheaper desalinization compared with using seawater. The methodology and findings in this study are instructional for other coastal areas with similar geology and history in the South China Sea.

  13. AlGaAs top solar cell for mechanical attachment in a multi-junction tandem concentrator solar cell stack

    NASA Technical Reports Server (NTRS)

    Dinetta, L. C.; Hannon, M. H.; Cummings, J. R.; Mcneeley, J. B.; Barnett, Allen M.

    1990-01-01

    Free-standing, transparent, tunable bandgap AlxGa1-xAs top solar cells have been fabricated for mechanical attachment in a four terminal tandem stack solar cell. Evaluation of the device results has demonstrated 1.80 eV top solar cells with efficiencies of 18 percent (100 X, and AM0) which would yield stack efficiencies of 31 percent (100 X, AM0) with a silicon bottom cell. When fully developed, the AlxGa1-xAs/Si mechanically-stacked two-junction solar cell concentrator system can provide efficiencies of 36 percent (AM0, 100 X). AlxGa1-xAs top solar cells with bandgaps from 1.66 eV to 2.08 eV have been fabricated. Liquid phase epitaxy (LPE) growth techniques have been used and LPE has been found to yield superior AlxGa1-xAs material when compared to molecular beam epitaxy and metal-organic chemical vapor deposition. It is projected that stack assembly technology will be readily applicable to any mechanically stacked multijunction (MSMJ) system. Development of a wide bandgap top solar cell is the only feasible method for obtaining stack efficiencies greater than 40 percent at AM0. System efficiencies of greater than 40 percent can be realized when the AlGaAs top solar cell is used in a three solar cell mechanical stack.

  14. Potentials and pitfalls of depth profile (10Be), burial isochron (26Al/10Be) and palaeomagnetic techniques for dating Early Pleistocene terrace deposits of the Moselle valley (Germany)

    NASA Astrophysics Data System (ADS)

    Rixhon, Gilles; Cordier, Stéphane; May, Simon Matthias; Kelterbaum, Daniel; Szemkus, Nina; Keulertz, Rebecca; Dunai, Tibor; Binnie, Steven; Hambach, Ulrich; Scheidt, Stephanie; Brueckner, Helmut

    2016-04-01

    Throughout the river network of the Rhenish Massif the so-called main terraces complex (MTC) forms the morphological transition between a wide upper palaeovalley and a deeply incised lower valley. The youngest level of this complex (YMT), directly located at the edge of the incised valley, represents a dominant geomorphic feature; it is often used as a reference level to identify the beginning of the main middle Pleistocene incision episode (Demoulin & Hallot, 2009). Although the main terraces are particularly well preserved in the lower Moselle valley, a questionable age of ca. 800 ka is assumed for the YMT, mainly based on the uncertain extrapolation of controversially interpreted palaeomagnetic data obtained in the Rhine valley. In this study, we applied terrestrial cosmogenic nuclide (TCN) dating (10Be/26Al) and palaeomagnetic dating to Moselle fluvial sediments of the MTC. To unravel the spatio-temporal characteristics of the Pleistocene evolution of the valley, several sites along the lower Moselle were sampled following two distinct TCN dating strategies: depth profiles where the original terrace (palaeo-) surface is well preserved and did not experience a major post-depositional burial (e.g., loess cover); and the isochron technique, where the sediment thickness exceeds 4.5-5 m. One terrace deposit was sampled for both approaches (reference site). In addition, palaeomagnetic sampling was systematically performed in each terrace sampled for TCN measurements. The TCN dating techniques show contrasting results for our reference site. Three main issues are observed for the depth profile method: (i) an inability of the modeled profile to constrain the 10Be concentration of the uppermost sample; (ii) an overestimated density value as model output; and (iii) a probable concentration steady state of the terrace deposits. By contrast, the isochron method yields a burial age estimate of 1.26 +0.29/-0.25 Ma, although one sample showed a depleted 26Al/10Be ratio

  15. Peat porewater chloride concentration profiles in the Everglades during wet/dry cycles from January 1996 to June 1998: Field measurements and theoretical analysis

    USGS Publications Warehouse

    Reddy, M.M.; Reddy, M.B.; Kipp, K.L.; Burman, A.; Schuster, P.; Rawlik, P.S., Jr.

    2008-01-01

    Water quality is a key aspect of the Everglades Restoration Project, the largest water reclamation and ecosystem management project proposed in the United States. Movement of nutrients and contaminants to and from Everglades peat porewater could have important consequences for Everglades water quality and ecosystem restoration activities. In a study of Everglades porewater, we observed complex, seasonally variable peat porewater chloride concentration profiles at several locations. Analyses and interpretation of these changing peat porewater chloride concentration profiles identifies processes controlling conservative solute movement at the peat-surface water interface, that is, solutes whose transport is minimally affected by chemical and biological reactions. We examine, with an advection-diffusion model, how alternating wet and dry climatic conditions in the Florida Everglades mediate movement of chloride between peat porewater and marsh surface water. Changing surface water-chloride concentrations alter gradients at the interface between peat and overlying water and hence alter chloride flux across that interface. Surface water chloride concentrations at two frequently monitored sites vary with marsh water depth, and a transfer function was developed to describe daily marsh surface water chloride concentration as a function of marsh water depth. Model results demonstrate that porewater chloride concentrations are driven by changing surface water chloride concentrations, and a sensitivity analysis suggests that inclusion of advective transport in the model improves the agreement between the calculated and the observed chloride concentration profiles. Copyright ?? 2007 John Wiley & Sons, Ltd.

  16. Use of an Oxygen-Insensitive Microscale Biosensor for Methane To Measure Methane Concentration Profiles in a Rice Paddy

    PubMed Central

    Damgaard, Lars R.; Revsbech, Niels Peter; Reichardt, Wolfgang

    1998-01-01

    An oxygen-insensitive microscale biosensor for methane was constructed by furnishing a previously described biosensor with an oxygen guard. The guard consisted of a glass capillary containing heterotrophic bacteria, which consumed oxygen diffusing through the tip membrane, thus preventing it from diffusing into the methane-sensing unit. Oxygen microprofiles were measured through the oxygen guard capillary, demonstrating the principle and limitations of the method. When the tip of the guard capillary was exposed to 100% oxygen at 21°C, heterotrophic oxygen consumption prevented oxygen from diffusing further than 170 μm into the capillary, whereas atmospheric levels of oxygen were consumed within 50 μm. The capacity of the oxygen guard for scavenging oxygen decreased with decreasing temperature, and atmospheric levels of oxygen caused oxygen penetration to 200 μm at 5°C. The sensors could be manufactured with tip diameters as small as 25 μm, and response times were about 1 min at room temperature. Pore water profiles of methane concentrations in a rice paddy soil were measured, and a strong correlation between the depths of oxygen penetration and methane appearance was observed as a function of the light regimen; this finding confirmed the role of microbenthic photosynthesis in limiting methane emissions from surfaces of waterlogged sediments and soils. PMID:16349527

  17. Boron concentration profiling by high angle annular dark field-scanning transmission electron microscopy in homoepitaxial δ-doped diamond layers

    SciTech Connect

    Araújo, D.; Alegre, M. P.; Piñero, J. C.; Fiori, A.; Bustarret, E.; Jomard, F.

    2013-07-22

    To develop further diamond related devices, the concentration and spatial location of dopants should be controlled down to the nanometer scale. Scanning transmission electron microscopy using the high angle annular dark field mode is shown to be sensitive to boron doping in diamond epilayers. An analytical procedure is described, whereby local boron concentrations above 10{sup 20} cm{sup −3} were quantitatively derived down to nanometer resolution from the signal dependence on thickness and boron content. Experimental boron local doping profiles measured on diamond p{sup −}/p{sup ++}/p{sup −} multilayers are compared to macroscopic profiles obtained by secondary ion mass spectrometry, avoiding reported artefacts.

  18. Comparing laboratory column test treatments with field profiles of fecal indicator bacteria and virus from concentrated source areas

    NASA Astrophysics Data System (ADS)

    Feighery, J.; Culligan, P.; Ferguson, A. S.; Mailloux, B. J.; McKay, L. D.; Ahmed, K.; Alam, M.; Huq, M.; Emch, M.; Serre, M. L.; Yunus, M.; van Geen, A.

    2010-12-01

    Fecal contamination of potable water supplies is prevalent throughout the developing world. In rural Bangladesh, groundwater contamination of shallow unconfined aquifers is attributed to the infiltration of fecal organisms from sewage ponds, sewage ditches and latrines. However, few studies conclusively link sources to wells at the scale required for microbial transport to occur. We present a combined field and laboratory investigation into the transport of the fecal indicator bacteria Escherichia coli (E. coli) and enteric viral indicator F+ RNA coliphage (MS-2) using drive point piezometers and extracted sediment cores. Fieldwork and coring took place in the Matlab Upazila, Bangladesh. Field measurements at the 100-cm scale were made using an array of three drive-point piezometers under highly contaminated ponds and canals over a 10-day period during the peak of the monsoon season. The profiles of E. coli detected under ponds and canals by a culture-based most probable number method were consistent with a first order filtration rate over the distances studied and filtration rates ranged from 1 - 8 m-1. In order to determine possible attachment mechanisms and the influence of sediment treatments applied in laboratory testing, duplicate column transport studies at the 10-cm scale were performed on intact cores processed immediately on-site, intact cores preserved by freezing, dried repacked sediment, acid-washed repacked sediment, and a uniform silica sand. Two ionic strengths (3.5 and 20 mM) were used to encompass the range of electrical conductivity typically found in the shallow portion of the aquifer. Columns were dissected and the attached E. coli quantified by section. Even at the solution chemistry less favorable for particle attachment (low ionic strength), filtration rates for the core tested on-site predict a transport distance of 0.5m for a 4-log unit reduction in E. coli concentration. Although the filtration rates found in the field study are lower

  19. Observation of vertcal CO2 concentration profiles in the lower-atmosphere using a compact direct detection 1.6 μm DIAL

    NASA Astrophysics Data System (ADS)

    Nagasawa, C.; Shibata, Y.; Abo, M.

    2015-12-01

    Knowledge of present carbon sources and sinks including their spatial profile and their variation in time is one of the essential informations for predicting future CO2 atmospheric concentration levels. Moewover, for the detailed analysis of forest carbon dynamics and CO2 fluxes of urban area, the CO2 concentration measurement techniques with high spatial and temporal resolution are required in the lower atmosphere. A differential absorption lidar (DIAL) is expected to measure atmospheric CO2 concentration profiles in the atmospheric boundary layer from a ground platform. We have succeeded to develop a compact direct detection 1.6 μm DIAL system for measuring CO2 concentration profiles in the lower atmosphere. This DIAL system consists of the optical parametric generator (OPG) transmitter that excited by the LD pumped Nd:YAG laser with high repetition rate and the receiving optics that included the near-infrared photomultiplier tube operating at the analog mode and the 25 cm telescope. We have succeeded in observing the daytime temporal change of vertical CO2 concentration profiles for the range from 0.25 to 2.5 km with integration time of 30 minutes and range resolution of 300 m. This compact direct detection CO2 DIAL is usefull for the estimation of CO2 flux. This work was financially supported by the System Development Program for Advanced Measurement and Analysis of the Japan Science and Technology Agency.

  20. Vertical distribution of chlorophyll a concentration and phytoplankton community composition from in situ fluorescence profiles: a first database for the global ocean

    NASA Astrophysics Data System (ADS)

    Sauzède, R.; Lavigne, H.; Claustre, H.; Uitz, J.; Schmechtig, C.; D'Ortenzio, F.; Guinet, C.; Pesant, S.

    2015-04-01

    In vivo chlorophyll a fluorescence is a proxy of chlorophyll a concentration, and is one of the most frequently measured biogeochemical properties in the ocean. Thousands of profiles are available from historical databases and the integration of fluorescence sensors to autonomous platforms led to a significant increase of chlorophyll fluorescence profile acquisition. To our knowledge, this important source of environmental data has not yet been included in global analyses. A total of 268 127 chlorophyll fluorescence profiles from several databases as well as published and unpublished individual sources were compiled. Following a robust quality control procedure detailed in the present paper, about 49 000 chlorophyll fluorescence profiles were converted in phytoplankton biomass (i.e. chlorophyll a concentration) and size-based community composition (i.e. microphytoplankton, nanophytoplankton and picophytoplankton), using a~method specifically developed to harmonize fluorescence profiles from diverse sources. The data span over five decades from 1958 to 2015, including observations from all major oceanic basins and all seasons, and depths ranging from surface to a median maximum sampling depth of around 700 m. Global maps of chlorophyll a concentration and phytoplankton community composition are presented here for the first time. Monthly climatologies were computed for three of Longhurst's ecological provinces in order to exemplify the potential use of the data product. Original data sets (raw fluorescence profiles) as well as calibrated profiles of phytoplankton biomass and community composition are available in open access at PANGAEA, Data Publisher for Earth and Environmental Science. Raw fluorescence profiles: http://doi.pangaea.de/10.1594/PANGAEA.844212 and Phytoplankton biomass and community composition: http://doi.pangaea.de/10.1594/PANGAEA.844485.

  1. Vertical distribution of chlorophyll a concentration and phytoplankton community composition from in situ fluorescence profiles: a first database for the global ocean

    NASA Astrophysics Data System (ADS)

    Sauzède, R.; Lavigne, H.; Claustre, H.; Uitz, J.; Schmechtig, C.; D'Ortenzio, F.; Guinet, C.; Pesant, S.

    2015-10-01

    In vivo chlorophyll a fluorescence is a proxy of chlorophyll a concentration, and is one of the most frequently measured biogeochemical properties in the ocean. Thousands of profiles are available from historical databases and the integration of fluorescence sensors to autonomous platforms has led to a significant increase of chlorophyll fluorescence profile acquisition. To our knowledge, this important source of environmental data has not yet been included in global analyses. A total of 268 127 chlorophyll fluorescence profiles from several databases as well as published and unpublished individual sources were compiled. Following a robust quality control procedure detailed in the present paper, about 49 000 chlorophyll fluorescence profiles were converted into phytoplankton biomass (i.e., chlorophyll a concentration) and size-based community composition (i.e., microphytoplankton, nanophytoplankton and picophytoplankton), using a method specifically developed to harmonize fluorescence profiles from diverse sources. The data span over 5 decades from 1958 to 2015, including observations from all major oceanic basins and all seasons, and depths ranging from the surface to a median maximum sampling depth of around 700 m. Global maps of chlorophyll a concentration and phytoplankton community composition are presented here for the first time. Monthly climatologies were computed for three of Longhurst's ecological provinces in order to exemplify the potential use of the data product. Original data sets (raw fluorescence profiles) as well as calibrated profiles of phytoplankton biomass and community composition are available on open access at PANGAEA, Data Publisher for Earth and Environmental Science. Raw fluorescence profiles: http://doi.pangaea.de/10.1594/PANGAEA.844212 and Phytoplankton biomass and community composition:

  2. TEMPORAL EVOLUTION OF SUB-NANOMETER COMPOSITIONAL PROFILES ACROSS THE GAMMA/GAMMA' INTERFACE IN A MODEL Ni-Al-Cr SUPERALLOY

    NASA Technical Reports Server (NTRS)

    Sudbrack, Chantal K.; Noebe, Ronald D.; Seidman, David N.

    2005-01-01

    Early-stage phase separation in a Ni-5.2 Al-14.2 Cr at.% superalloy, isothermally decomposing at 873 K, is investigated with atom-probe tomography. Sub-nanometer scale compositional profiles across the gamma/gamma'(L12) interfaces demonstrate that both the gamma-matrix and the gamma'-precipitate compositions evolve with time. Observed chemical gradients of Al depletion and Cr enrichment adjacent to the gamma'-precipitates are transient, consistent with well-established model predictions for diffusion-limited growth, and mark the first detailed observation of this phenomenon. Furthermore, it is shown that Cr atoms are kinetically trapped in the growing precipitates.

  3. Simultaneous determination of Si, Al and Na concentrations by particle induced gamma-ray emission and applications to reference materials and ceramic archaeological artifacts

    NASA Astrophysics Data System (ADS)

    Dasari, K. B.; Chhillar, S.; Acharya, R.; Ray, D. K.; Behera, A.; Lakshmana Das, N.; Pujari, P. K.

    2014-11-01

    A particle induced gamma ray emission (PIGE) method using 4 MeV proton beam was standardized for simultaneous determination of Si, Al and Na concentrations and has been applied for non-destructive analysis of several reference materials and archaeological clay pottery samples. Current normalized count rates of gamma-rays for the three elements listed above were obtained by an in situ method using Li as internal standard. The paper presents application of the in situ current normalized PIGE method for grouping study of 39 clay potteries, obtained from Rajasthan and Andhra Pradesh states of India. Grouping of artifacts was carried out using the ratios of SiO2 to Al2O3 concentrations, due to their non volatile nature. Powder samples and elemental standards in pellet forms (cellulose matrix) were irradiated using the 4 MeV proton beam (∼10 nA) from the 3 MV tandem accelerator at IOP Bhubaneswar, and assay of prompt gamma rays was carried out using a 60% relative efficiency HPGe detector coupled to MCA. The concentration ratio values of SiO2/Al2O3 indicated that pottery samples fell into two major groups, which are in good agreement with their collection areas. Reference materials from IAEA and NIST were analyzed for quantification of Si, Al and Na concentrations as a part of validation as well as application of PIGE method.

  4. COSIM: A Finite-Difference Computer Model to Predict Ternary Concentration Profiles Associated with Oxidation and Interdiffusion of Overlay-Coated Substrates

    NASA Technical Reports Server (NTRS)

    Nesbitt, James A.

    2000-01-01

    A finite-difference computer program (COSIM) has been written which models the one-dimensional, diffusional transport associated with high-temperature oxidation and interdiffusion of overlay-coated substrates. The program predicts concentration profiles for up to three elements in the coating and substrate after various oxidation exposures. Surface recession due to solute loss is also predicted. Ternary cross terms and concentration-dependent diffusion coefficients are taken into account. The program also incorporates a previously-developed oxide growth and spalling model to simulate either isothermal or cyclic oxidation exposures. In addition to predicting concentration profiles after various oxidation exposures, the program can also be used to predict coating fife based on a concentration dependent failure criterion (e.g., surface solute content drops to two percent). The computer code, written in an extension of FORTRAN 77, employs numerous subroutines to make the program flexible and easily modifiable to other coating oxidation problems.

  5. COSIM: A Finite-Difference Computer Model to Predict Ternary Concentration Profiles Associated With Oxidation and Interdiffusion of Overlay-Coated Substrates

    NASA Technical Reports Server (NTRS)

    Nesbitt, James A.

    2001-01-01

    A finite-difference computer program (COSIM) has been written which models the one-dimensional, diffusional transport associated with high-temperature oxidation and interdiffusion of overlay-coated substrates. The program predicts concentration profiles for up to three elements in the coating and substrate after various oxidation exposures. Surface recession due to solute loss is also predicted. Ternary cross terms and concentration-dependent diffusion coefficients are taken into account. The program also incorporates a previously-developed oxide growth and spalling model to simulate either isothermal or cyclic oxidation exposures. In addition to predicting concentration profiles after various oxidation exposures, the program can also be used to predict coating life based on a concentration dependent failure criterion (e.g., surface solute content drops to 2%). The computer code is written in FORTRAN and employs numerous subroutines to make the program flexible and easily modifiable to other coating oxidation problems.

  6. Influence of c-axis orientation and scandium concentration on infrared active modes of magnetron sputtered ScxAl1-xN thin films

    NASA Astrophysics Data System (ADS)

    Mayrhofer, P. M.; Eisenmenger-Sittner, C.; Euchner, H.; Bittner, A.; Schmid, U.

    2013-12-01

    Doping of wurtzite aluminium nitride (AlN) with scandium (Sc) significantly enhances the piezoelectric properties of AlN. ScxAl1-xN thin films with different Sc concentrations (x = 0 to 0.15) were deposited by DC reactive magnetron sputtering. Infrared (IR) absorbance spectroscopy was applied to investigate the Sc concentration dependent shift of the IR active modes E1(TO) and A1(TO). These results are compared to ab initio simulations, being in excellent agreement with the experimental findings. In addition, IR spectroscopy is established as an economical and fast method to distinguish between thin films with a high degree of c-axis orientation and those exhibiting mixed orientations.

  7. Effect of LiAlO{sub 2} nanoparticle filler concentration on the electrical properties of PEO–LiClO{sub 4} composite

    SciTech Connect

    Masoud, E.M.; El-Bellihi, A.-A.; Bayoumy, W.A.; Mousa, M.A.

    2013-03-15

    Highlights: ► Structural modification of nano LiAlO{sub 2} filler increased conductivity. ► Good ionic conductivity for (LiAlO{sub 2}){sub 1.5}(PEO){sub 11}(LiClO{sub 4}) at room temperature. ► Nano LiAlO{sub 2} filler enhanced both ion migration and orientation. ► High dielectric properties for (LiAlO{sub 2}){sub 1.5}(PEO){sub 11}(LiClO{sub 4}) at room temperature. - Abstract: Nano-composite polymer electrolytes are receiving attention as potential candidates to be used as electrolyte membranes in lithium polymer batteries and other devices. In this work, polyethylene oxide–LiClO{sub 4} based composite polymer electrolyte was prepared by solution casting method. The effect of LiAlO{sub 2} nanoparticle ceramic filler concentration on the structure and electrical conduction of the composite was studied. Nano-LiAlO{sub 2} was synthesized by sol–gel method. The samples were characterized using X-ray diffraction, Fourier Transmission-Infra Red, Differential Scanning Calorimetry, and tested by dielectric properties, Direct and Alternating current measurements as well as by impedance spectroscopy. All samples showed a behavior referring to an ionic conduction. Generally, the melting temperature of the polymer electrolyte decreased with filler concentration. Both thermal property and filler concentration influenced conductivity value. At room temperature, the highest ionic conductivity was 9.76 × 10{sup −5} ohm{sup −1} cm{sup −1} for sample with a composition of (LiAlO{sub 2}){sub 1.5}(polyethylene oxide){sub 11}(LiClO{sub 4}). All results were correlated and discussed.

  8. A comparison of measured and modeled suspended sediment concentration profiles during different types of meteorological events on the inner-shelf of Long Bay, South Carolina

    NASA Astrophysics Data System (ADS)

    Wren, P. A.; Ma, Y.

    2010-12-01

    An instrumented quadrapod was deployed on the inner-shelf of Long Bay, South Carolina at a depth of approximately 7 meters from July 2008 - December 2009. A multi-frequency Acoustic Backscatter Sensor (ABS) and a pulse-coherent Acoustic Doppler Current Profiler (PC-ADCP) were used to collect co-located long-term measurements of suspended sediment concentrations and high-resolution velocity profiles throughout the bottom boundary layer. To invert the acoustic backscatter voltage collected by the ABS, a semi-empirical backscattering theory (Thorne and Hanes, 2002) was first verified with sediment chamber measurements using local sediments. The verified theory was then employed to determine sediment grain size and suspended sediment concentrations. Additionally, to complement the field observations, two different 1-D bottom boundary layer models (Styles and Glenn, 2000 and Wiberg and Smith, 1983) were applied to estimate the bed shear stress, velocity and suspended sediment concentration profiles. Although both models are based on boundary layer theory (Smith,1977; Grant and Madsen, 1979), and require as inputs of wave and current velocities as well as characteristics of sea-bed sediment, they are distinct in some practical applications such as eddy-viscosity profile, ripple dimension estimation, model gridding, etc. Recorded waves, currents, and acoustic backscatter data revealed that nineteen sediment transport events occurred during the eighteen month study period, which resulted in an order of magnitude range of suspended sediment concentrations. Comparisons of sediment concentration profiles between the two 1-D models and the field measurements were conducted during several different types of sediment transport events. The events that were used for the comparisons included two types of frequently occurring frontal systems, as well a direct hit from Tropical Storm Hannah. During the selected events near-bottom orbital velocities ranged from 20 - 60 cm s-1 and

  9. Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis.

    PubMed

    Wilde, Markus; Ohno, Satoshi; Ogura, Shohei; Fukutani, Katsuyuki; Matsuzaki, Hiroyuki

    2016-01-01

    Nuclear reaction analysis (NRA) via the resonant (1)H((15)N,αγ)(12)C reaction is a highly effective method of depth profiling that quantitatively and non-destructively reveals the hydrogen density distribution at surfaces, at interfaces, and in the volume of solid materials with high depth resolution. The technique applies a (15)N ion beam of 6.385 MeV provided by an electrostatic accelerator and specifically detects the (1)H isotope in depths up to about 2 μm from the target surface. Surface H coverages are measured with a sensitivity in the order of ~10(13) cm(-2) (~1% of a typical atomic monolayer density) and H volume concentrations with a detection limit of ~10(18) cm(-3) (~100 at. ppm). The near-surface depth resolution is 2-5 nm for surface-normal (15)N ion incidence onto the target and can be enhanced to values below 1 nm for very flat targets by adopting a surface-grazing incidence geometry. The method is versatile and readily applied to any high vacuum compatible homogeneous material with a smooth surface (no pores). Electrically conductive targets usually tolerate the ion beam irradiation with negligible degradation. Hydrogen quantitation and correct depth analysis require knowledge of the elementary composition (besides hydrogen) and mass density of the target material. Especially in combination with ultra-high vacuum methods for in-situ target preparation and characterization, (1)H((15)N,αγ)(12)C NRA is ideally suited for hydrogen analysis at atomically controlled surfaces and nanostructured interfaces. We exemplarily demonstrate here the application of (15)N NRA at the MALT Tandem accelerator facility of the University of Tokyo to (1) quantitatively measure the surface coverage and the bulk concentration of hydrogen in the near-surface region of a H2 exposed Pd(110) single crystal, and (2) to determine the depth location and layer density of hydrogen near the interfaces of thin SiO2 films on Si(100). PMID:27077920

  10. Gene expression profiling for human iPS-derived motor neurons from sporadic ALS patients reveals a strong association between mitochondrial functions and neurodegeneration

    PubMed Central

    Alves, Chrystian J.; Dariolli, Rafael; Jorge, Frederico M.; Monteiro, Matheus R.; Maximino, Jessica R.; Martins, Roberto S.; Strauss, Bryan E.; Krieger, José E.; Callegaro, Dagoberto; Chadi, Gerson

    2015-01-01

    Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease that leads to widespread motor neuron death, general palsy and respiratory failure. The most prevalent sporadic ALS form is not genetically inherited. Attempts to translate therapeutic strategies have failed because the described mechanisms of disease are based on animal models carrying specific gene mutations and thus do not address sporadic ALS. In order to achieve a better approach to study the human disease, human induced pluripotent stem cell (hiPSC)-differentiated motor neurons were obtained from motor nerve fibroblasts of sporadic ALS and non-ALS subjects using the STEMCCA Cre-Excisable Constitutive Polycistronic Lentivirus system and submitted to microarray analyses using a whole human genome platform. DAVID analyses of differentially expressed genes identified molecular function and biological process-related genes through Gene Ontology. REVIGO highlighted the related functions mRNA and DNA binding, GTP binding, transcription (co)-repressor activity, lipoprotein receptor binding, synapse organization, intracellular transport, mitotic cell cycle and cell death. KEGG showed pathways associated with Parkinson's disease and oxidative phosphorylation, highlighting iron homeostasis, neurotrophic functions, endosomal trafficking and ERK signaling. The analysis of most dysregulated genes and those representative of the majority of categorized genes indicates a strong association between mitochondrial function and cellular processes possibly related to motor neuron degeneration. In conclusion, iPSC-derived motor neurons from motor nerve fibroblasts of sporadic ALS patients may recapitulate key mechanisms of neurodegeneration and may offer an opportunity for translational investigation of sporadic ALS. Large gene profiling of differentiated motor neurons from sporadic ALS patients highlights mitochondrial participation in the establishment of autonomous mechanisms associated with sporadic ALS

  11. Nature and reactivity of layered double hydroxides formed by coprecipitating Mg, Al and As(V): Effect of arsenic concentration, pH, and aging.

    PubMed

    Sommella, Alessia; Caporale, Antonio G; Denecke, Melissa A; Mangold, Stefan; Pigna, Massimo; Santoro, Anna; Terzano, Roberto; Violante, Antonio

    2015-12-30

    Arsenic (As) co-precipitation is one of the major processes controlling As solubility in soils and waters. When As is co-precipitated with Al and Mg, the possible formation of layered double hydroxides (LDHs) and other nanocomposites can stabilize As in their structures thus making this toxic element less available. We investigated the nature and reactivity of Mg-Al-arsenate [As(V)] co-precipitated LDHs formed in solution affected by As concentration, pH, and aging. At the beginning of the co-precipitation process, poorly crystalline LDH and non-crystalline Al(Mg)-oxides form. Prolonged aging of the samples promotes crystallization of LDHs, evidenced by an increase in As K XANES intensities and XRD peak intensities. During aging Al- and/or Mg-oxides are likely transformed by dissolution/re-precipitation processes into more crystalline but still defective LDHs. Surface area, chemical composition, reactivity of the precipitates, and anion exchange properties of As(V) in the co-precipitates are influenced by pH, aging, and As concentration. This study demonstrates that (i) As(V) retards or inhibits the formation and transformation of LDHs and (ii) more As(V) is removed from solution if co-precipitated with Mg and Al than by sorption onto well crystallized LDHs. PMID:26241870

  12. Effects of Substrate Surface Defects and Te Dopant Concentration on Crystalline Quality and Electrical Characteristics of AlGaAsSb Epitaxial Layers

    SciTech Connect

    H Ehsani; N Lewis; G Nichols; L Danielson; M Dashiell; Z Shellenbarger; C Wang

    2004-10-27

    Tellurium doped AlGaAsSb epitaxial layers were grown lattice-matched on GaSb substrates and lattice-mismatched on semi-insulating GaAs substrates by organometallic vapor phase epitaxy. Secondary ion mass spectroscopy and Hall data showed that the ratio of carrier concentration to Te concentration decreases from 40% to 5% when the Te concentration increases from 4.8 x 10{sup 17} cm{sup -3} to 1.3 x 10{sup 19} cm{sup -3}. Transmission electron microscopy (TEM) showed that the material with heavily doped Te generates a high density (about 10{sup 8} cm{sup 2}) of planar defects. Most of the Te-related defects originate at the GaSb buffer layer/AlGaAsSb epilayer interface. In addition, discrete precipitates were observed in the heavily doped AlGaAsSb layer. TEM imaging revealed amorphous defects (likely residual native oxides) along the GaSb substrate/GaSb buffer interface. High resolution TEM imaging revealed high quality growth beyond the GaSb-buffer/GaSb-substrate interfacial defects. The microstructural impact of GaSb-buffer/GaSb-substrate interface defects on the crystalline quality of AlGaAsSb layers is insignificant.

  13. Exploration of PBPK Model-Calculation of Drug Time Course in Tissue Using IV Bolus Drug Plasma Concentration-Time Profile and the Physiological Parameters of the Organ.

    PubMed

    Berezhkovskiy, Leonid M

    2016-08-01

    An uncommon innovative consideration of the well-stirred linear physiologically based pharmacokinetic model and the drug plasma concentration-time profile, which is measured in routine intravenous bolus pharmacokinetic study, was applied for the calculation of the drug time course in human tissues. This cannot be obtained in the in vivo pharmacokinetic study. The physiological parameters of the organ such as organ tissue volume, organ blood flow rate, and its vascular volume were used in the calculation. The considered method was applied to calculate the time course of midazolam, alprazolam, quinidine, and diclofenac in human organs or tissues. The suggested method might be applied for the prediction of drug concentration-time profile in tissues and consequently the drug concentration level in the targeted tissue, as well as the possible undesirable toxic levels in other tissues. PMID:27290628

  14. A comparative study on shock compression of nanocrystalline Al and Cu: Shock profiles and microscopic views of plasticity

    SciTech Connect

    Ma, Wen; Hou, Yong; Zhu, Wenjun

    2013-10-28

    Shock compressions of nanocrystalline (nc) metals Al and Cu with the same grain size and texture are studied by using molecular dynamics simulations. Results have revealed that the shock front of both Al and Cu can be divided into three stages: elastic, grain-boundary-mediated, and dislocation-mediated plastic deformation. The transition planes among these three stages are proven to be non-planar by two-dimensional shock response analysis, including local stress, shear, temperature, and atom configuration. The difference between shocked Al and Cu is that the rise rate of the elastic stage of Cu is slightly higher than that of Al, and that the shock-front width of Al is wider than Cu at the same loading conditions. For the plastic stage, the dislocation density of shocked Al is lower than Cu, and the contribution of grain-boundary-mediated plasticity to shock front and strain for nc Al is more pronounced than for nc Cu. These results are explained through intrinsic material properties and atomistic analysis of the plastic process. In the case of the shocked Al sample, partial dislocations, perfect dislocations, and twins are observed, but few evidence of perfect dislocations and twins are observed in the shocked Cu.

  15. Effect of Substrate Surface Defects and Te Dopant Concentration on Crystalline Quality and Electrical Characteristics of AlGaAsSb Epitaxial Layers

    SciTech Connect

    H Ehsani; N Lewis; G Nichols; L Danielson; M Dashiell; Z Shellenbarger; C Wang

    2006-01-04

    The influence of GaSb substrate surface defects such as native oxides on the crystalline quality of epitaxial layers was investigated using transmission electron microscopy (TEM). Cross sectional TEM imaging showed that there are discrete defects at the GaSb-substrate/epilayer interface. Secondary ion mass spectroscopy (SIMS) results revealed high oxygen concentration at the interface, indicating that the defects are likely oxides and presumed to be native oxides since other impurities were not detected. High resolution TEM micrographs showed that the subsequent growth of the epilayer continues beyond the defects without any additional defect generation or propagation. Tellurium doped AlGaAsSb epitaxial layers were grown lattice-matched on GaSb substrates and lattice-mismatched on semi-insulating GaAs substrates by organometallic vapor phase epitaxy. Secondary ion mass spectroscopy and Hall data showed that the ratio of carrier concentration to Te concentration decreases significantly when the carrier concentration increases from 2.5 x 10{sup 17} cm{sup -3} to 6.5 x 10{sup 17} cm{sup -3}. TEM imaging showed that the material with heavily doped Te generates a high density (about 10{sup 8} cm{sup 2}) of planar defects (stacking fault) located on (111) planes. Most of the Te-related defects originate at the GaSb buffer layer/AlGaAsSb epilayer interface. In addition, discrete precipitates were observed in the heavily doped AlGaAsSb layer.

  16. Evaluation of the Impact of AlRS Radiance and Profile Data Assimilation in Partly Cloudy Regions

    NASA Technical Reports Server (NTRS)

    Zavodsky, Bradely; Srikishen, Jayanthi; Jedlovec, Gary

    2013-01-01

    Parallel experiments using AIRS L1B and L2 retrieved profiles were run for 29 case study days for early Winter 2011. Forecasts over and downstream regions of low, opaque cloudy regions yield improved T and Z anomaly correlations when non-thinned set of profiles is assimilated instead of radiances. Initial results indicate that GSI does a good job on the whole of determining cloud-free radiances there are some areas coincident with areas of larger profile impact that are misrepresented (compared to MODIS) that may result in reduced analysis impact.

  17. Analysis of the co-deposition of Al2O3 particles with nickel by an electrolytic route: The influence of organic additives presence and Al2O3 concentration

    NASA Astrophysics Data System (ADS)

    Temam, H. B.; Temam, E. G.

    2016-04-01

    Alloy coatings were prepared by co-deposition of Al2O3 particles in Ni matrix on carbon steel substrate from nickel chloride bath in which metallic powders were held in suspension. The influence of metal powder amount in the bath on chemical composition, morphology, thickness, microhardness and corrosion behavior of obtained coatings, has been investigated. It was shown that the presence of Al2O3 particles in deposit greatly improves the hardness and the wear resistance of alloy coatings. Characterization by microanalysis (EDX) of the various deposits elaborated confirms that the rate of particles incorporated increases as the concentration of solid particles increasing. The results showed that the presence of organic additives in Ni-Al2O3 electrolyte deposition led to an increase in the hardness and corrosion resistance of the deposits.

  18. Remote sensing of temperature and concentration profiles of a gas jet by coupling infrared emission spectroscopy and LIDAR for characterization of aircraft engine exhaust

    NASA Astrophysics Data System (ADS)

    Offret, J.-P.; Lebedinsky, J.; Navello, L.; Pina, V.; Serio, B.; Bailly, Y.; Hervé, P.

    2015-05-01

    Temperature data play an important role in the combustion chamber since it determines both the efficiency and the rate of pollutants emission of engines. Air pollution problem concerns the emissions of gases such as CO, CO2, NO, NO2, SO2 and also aerosols, soot and volatile organic compounds. Flame combustion occurs in hostile environments where temperature and concentration profiles are often not easy to measure. In this study, a temperature and CO2 concentration profiles optical measurement method, suitable for combustion analysis, is discussed and presented. The proposed optical metrology method presents numerous advantages when compared to intrusive methods. The experimental setup comprises a passive radiative emission measurement method combined with an active laser-measurement method. The passive method is based on the use of gas emission spectroscopy. The experimental spectrometer device is coupled with an active method. The active method is used to investigate and correct complex flame profiles. This method similar to a LIDAR (Light Detection And Ranging) device is based on the measurement of Rayleigh scattering of a short laser pulse recorded using a high-speed streak camera. The whole experimental system of this new method is presented. Results obtained on a small-scale turbojet are shown and discussed in order to illustrate the potentials deliver by the sophisticated method. Both temperature and concentration profiles of the gas jet are presented and discussed.

  19. Concentration- and Temperature-Induced Phase Transitions in PrAlO3-SrTiO3 System.

    PubMed

    Vasylechko, Leonid; Stepchuk, Roman; Prots, Yuri; Rosner, Helge

    2016-12-01

    Single-phase mixed aluminates-titanates Pr1-x Sr x Al1-x Ti x O3 (x = 0.1, 0.2, 0.3, 0.5, 0.7) with rhombohedral perovskite structure were prepared by solid-state reaction technique at 1823-1873 K. Morphotropic rhombohedral-to-cubic phase transition in Pr1-x Sr x Al1-x Ti x O3 series is predicted to occur at x = 0.88. The temperature-induced structural phase transition R  [Formula: see text]  с - Pm [Formula: see text]  m in Pr0.5Sr0.5Al0.5Ti0.5O3, detected at 930 K by in situ high-temperature X-ray synchrotron powder diffraction, occurs at considerably lower temperature as the corresponding transformation in the parent compound PrAlO3 (1770 K). Such remarkable drop of the transition temperature is explained by gradual decrease of the perovskite structure deformation in the Pr1-x Sr x Al1-x Ti x O3 series with increasing Sr and Ti contents as a consequence of the increasing Goldschmidt tolerance factor. For Pr0.3Sr0.7Al0.3Ti0.7O3 phase, a sequence of the low-temperature phase transformation R  [Formula: see text]  с - Immb(C2/m) - I4/mcm was detected. PMID:26759353

  20. The determination of the chemical composition profile of the GaAs/AlGaAs heterostructures designed for quantum cascade lasers by means of synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Gaca, JarosŁaw; Wójcik, Marek; Bugajski, Maciej; Kosiel, Kamil

    2011-10-01

    The chemical composition profile of the GaAs/AlGaAs quantum cascade structures grown on (0 0 1) GaAs substrate by molecular beam epitaxy is studied by a synchrotron radiation high-resolution X-ray diffraction. The analysis is carried out for the whole structure as well for its parts. In order to determine some structural parameters, such as: the thickness and chemical composition of each layer making up the investigated structure, the profile of the interface between succeeding layers, and the preservation of the structure periodicity, the experimental X-ray diffraction profiles are compared with simulated ones calculated by means of Darwin dynamical theory of X-ray diffraction. It is shown that this method gives correct chemical composition profiles and allows for the evaluation of the deviations from the designed values of the structural parameters in most investigated cases. Limits of the method are discussed, especially by the determination of the chemical composition profile for thin heterostructures, such as those making active or injector regions.

  1. Reverse current pulse method to restore uniform concentration profiles in ion-selective membranes. Part I: Galvanostatic pulse methods with decreased cycle time

    PubMed Central

    Zook, Justin M.; Lindner, Ernő

    2009-01-01

    The applications of ion-selective electrodes (ISEs) have been broadened through the introduction of galvanostatic current pulse methods in potentiometric analysis. An important requirement in these applications is the restoration of the uniform equilibrium concentration profiles in the ISE membrane between each measurement. The simplest restoration method is zero current relaxation, in which the membrane relaxes under open-circuit conditions in a diffusion-controlled process. This paper presents a novel restoration method using a reverse current pulse. An analytic model for this restoration method is derived to predict the concentration profiles inside ISE membranes following galvanostatic current pulses. This model allows the calculation of the voltage transients as the membrane voltage relaxes back towards its zero-current equilibrium value. The predicted concentration profiles and voltage transients are confirmed using spectroelectrochemical microscopy (SpECM). The reverse current restoration method described in this paper reduces the voltage drift and voltage error by 10 to 100 times compared to the zero current restoration method. Therefore, this new method provides faster and more reproducible voltage measurements in most chronopotentiometric ISE applications, such as improving the detection limit and determining concentrations and diffusion coefficients of membrane species. One limitation of the reverse current restoration method is that it cannot be used in a few applications that require background electrolyte loaded membranes without excess of lipophilic cation exchanger. PMID:19459603

  2. An inverted AlGaAs/GaAs patterned-Ge tunnel junction cascade concentrator solar cell

    SciTech Connect

    Venkatasubramanian, R. )

    1993-01-01

    This report describes work to develop inverted-grown Al[sub 0.34]Ga[sub 0.66]As/GaAs cascades. Several significant developments are reported on as follows: (1) The AM1.5 1-sun total-area efficiency of the top Al[sub 0.34]Ga[sub 0.66]As cell for the cascade was improved from 11.3% to 13.2% (NREL measurement [total-area]). (2) The cycled'' organometallic vapor phase epitaxy growth (OMVPE) was studied in detail utilizing a combination of characterization techniques including Hall-data, photoluminescence, and secondary ion mass spectroscopy. (3) A technique called eutectic-metal-bonding (EMB) was developed by strain-free mounting of thin GaAs-AlGaAs films (based on lattice-matched growth on Ge substrates and selective plasma etching of Ge substrates) onto Si carrier substrates. Minority-carrier lifetime in an EMB GaAs double-heterostructure was measured as high as 103 nsec, the highest lifetime report for a freestanding GaAs thin film. (4) A thin-film, inverted-grown GaAs cell with a 1-sun AM1.5 active-area efficiency of 20.3% was obtained. This cell was eutectic-metal-bonded onto Si. (5) A thin-film inverted-grown, Al[sub 0.34]Ga[sub 0.66]As/GaAs cascade with AM1.5 efficiency of 19.9% and 21% at 1-sun and 7-suns, respectively, was obtained. This represents an important milestone in the development of an AlGaAs/GaAs cascade by OMVPE utilizing a tunnel interconnect and demonstrates a proof-of-concept for the inverted-growth approach.

  3. Effect of geometrical stress concentrators on the current-induced suppression of the serrated deformation in an aluminum-magnesium AlMg5 alloy

    NASA Astrophysics Data System (ADS)

    Shibkov, A. A.; Zolotov, A. E.; Zheltov, M. A.; Denisov, A. A.; Gasanov, M. F.; Kochegarov, S. S.

    2016-05-01

    The effect of an electric current on the band formation and the serrated deformation of planar specimens made of an aluminum-magnesium AlMg5 alloy and weakened by holes is experimentally studied. It is found that the concentration of elastic stress fields and the self-localized unstable plastic deformation field near a hole decreases the critical strain of appearance of the first stress drop and hinders the currentinduced suppression of band formation and the serrated Portevin-Le Chatelier deformation. These results are shown not to be related to the concentration of Joule heat near a hole.

  4. PUMA - a new mathematical model for the rapid calculation of steady-state concentration profiles in mixer-settler extraction, partitioning, and stripping contactors using the Purex process

    SciTech Connect

    Geldard, J.F.

    1986-11-01

    The mathematical basis for a computer code PUMA (Plutonium-Uranium-Matrix-Algorithm) is described. The code simulates steady-state concentration profiles of solvent extraction contactors used in the Purex process, directly without first generating the transient behavior. The computational times are reduced, with no loss of accuracy, by about tenfold over those required by codes that generate the steady-state profiles via transient state conditions. Previously developed codes that simulate the steady-state conditions directly are not applicable to partitioning contactors, whereas PUMA is applicable to all contactors in the Purex process. Since most difficulties are encountered with partitioning contactors when simulating steady-state profiles via transient state conditions, it is with these contactors that the greatest saving in computer times is achieved.

  5. Changes in /sup 22/Na influx and outflux in Daphnia magna (Straus) as a function of elevated Al concentrations in soft water at low pH

    SciTech Connect

    Havas, M.; Likens, G.E.

    1985-11-01

    The effects of aluminum on sodium regulation by the freshwater crustacean Daphnia magna were determined. /sup 22/Na influx and outflux experiments were conducted in soft water adjusted to pH 4.5, 5.0, and 6.5 (reference pH) with either ambient (0.02 mg/liter) or high (1.02 mg/liter) concentrations of total Al. The results indicate that Al toxicity was pH dependent. Aluminum increased the rate of morbidity of D. magna at pH 6.5, had no additional effect to those of hydrogen ions (H/sup +/) at pH 5.0, and reduced the rate of morbidity at pH 4.5. Both H/sup +/ and total Al concentrations interfered with Na regulation, although it was possible to distinguish between their respective effects by using /sup 22/Na. At pH 6.5, Al decreased /sup 22/Na influx (by 46%) and increased /sup 22/Na outflux (by 25%), which led to a net loss of Na. At pH 5.0, Al reduced /sup 22/Na influx (by 58%) but had not additional effect to that of H/sup +/ on /sup 22/Na outflux. At pH 4.5, /sup 22/Na influx was significantly inhibited (by 73%) compared with the reference pH 6.5 treatment even in the absence of Al. Aluminum decreased /sup 22/Na outflux (by 31%) at pH 4.5, which reduced the net loss of Na and temporarily prolonged survival of the daphnids. These results indicate that Al affects both /sup 22/Na influx and outflux in D. magna. The lower rate of Na uptake may involve a denaturation of the enzyme responsible for the active uptake of Na. At pH 6.5, the increased outflux of /sup 22/Na may be due to either increased membrane permeability or increased renal losses (or both). At pH 4.5, the reduced outflux of /sup 22/Na resembles the amelioration that occurs in the presence of elevated Ca concentrations.

  6. Vertically-resolved profiles of mass concentrations and particle backscatter coefficients of Asian dust plumes derived from lidar observations of silicon dioxide.

    PubMed

    Noh, Youngmin; Müller, Detlef; Shin, Sung-Kyun; Shin, Dongho; Kim, Young J

    2016-01-01

    This study presents a method to retrieve vertically-resolved profiles of dust mass concentrations by analyzing Raman lidar signals of silicon dioxide (quartz) at 546nm. The observed particle plumes consisted of mixtures of East Asian dust with anthropogenic pollution. Our method for the first time allows for extracting the contribution of the aerosol component "pure dust" contained in the aerosol type "polluted dust". We also propose a method that uses OPAC (Optical Properties of Aerosols and Clouds) and the mass concentrations profiles of dust in order to derive profiles of backscatter coefficients of pure dust in mixed dust/pollution plumes. The mass concentration of silicon dioxide (quartz) in the atmosphere can be estimated from the backscatter coefficient of quartz. The mass concentration of dust is estimated by the weight percentage (38-77%) of mineral quartz in Asian dust. The retrieved dust mass concentrations are classified into water soluble, nucleation, accumulation, mineral-transported and coarse mode according to OPAC. The mass mixing ratio of 0.018, 0.033, 0.747, 0.130 and 0.072, respectively, is used. Dust extinction coefficients at 550nm were calculated by using OPAC and prescribed number concentrations for each of the 5 components. Dust backscatter coefficients were calculated from the dust extinction coefficients on the basis of a lidar ratio of 45±3sr at 532nm. We present results of quartz-Raman measurements carried out on the campus of the Gwangju Institute of Science and Technology (35.10°N, 126.53°E) on 15, 16, and 21 March 2010. PMID:25937543

  7. A multiscale computational model of spatially resolved calcium cycling in cardiac myocytes: from detailed cleft dynamics to the whole cell concentration profiles

    PubMed Central

    Vierheller, Janine; Neubert, Wilhelm; Falcke, Martin; Gilbert, Stephen H.; Chamakuri, Nagaiah

    2015-01-01

    Mathematical modeling of excitation-contraction coupling (ECC) in ventricular cardiac myocytes is a multiscale problem, and it is therefore difficult to develop spatially detailed simulation tools. ECC involves gradients on the length scale of 100 nm in dyadic spaces and concentration profiles along the 100 μm of the whole cell, as well as the sub-millisecond time scale of local concentration changes and the change of lumenal Ca2+ content within tens of seconds. Our concept for a multiscale mathematical model of Ca2+ -induced Ca2+ release (CICR) and whole cardiomyocyte electrophysiology incorporates stochastic simulation of individual LC- and RyR-channels, spatially detailed concentration dynamics in dyadic clefts, rabbit membrane potential dynamics, and a system of partial differential equations for myoplasmic and lumenal free Ca2+ and Ca2+-binding molecules in the bulk of the cell. We developed a novel computational approach to resolve the concentration gradients from dyadic space to cell level by using a quasistatic approximation within the dyad and finite element methods for integrating the partial differential equations. We show whole cell Ca2+-concentration profiles using three previously published RyR-channel Markov schemes. PMID:26441674

  8. Concentration and speciation of antimony and arsenic in soil profiles around the world's largest antimony metallurgical area in China.

    PubMed

    Yang, Hailin; He, Mengchang; Wang, Xiangqin

    2015-02-01

    Mining and smelting activities contribute large amounts of heavy metal pollution to the environment. In this study, four 75- or 80-cm-deep soil profiles in the vicinity of the Xikuangshan Sb smelter were sampled and studied by combination of bulk chemical analysis, sequential extraction procedure, and speciation analysis of Sb and As, which are in order to assess the vertical mobility of metal/metalloid contaminants (Sb, As, Cd, and Hg). The heavy contamination in the soil profiles is mostly located in the uppermost soil layers enriched in organic matter (<40 cm) and exhibited downward migration in the soil profiles. Sb and As, being substantially bound in the exchangeable fractions by sequential extraction studies, showed significant mobility in the profiles. Sb(III), Sb(V), As(III), and As(V) were found in all of the soil samples, and certain methylated states of Sb (TMSb) and As (MMA, DMA) were also present in the lower layer soil samples. PMID:24969304

  9. A new perspective on the Fukushima releases brought by newly available air concentration observations (Tsuruta et al, 2014) and reliable meteorological fields

    NASA Astrophysics Data System (ADS)

    Saunier, Olivier; Mathieu, Anne; Sekiyama, Thomas; Kajino, Mizuo; Adachi, Kouji; Bocquet, Marc; Igarashi, Yasuhito; Didier, Damien

    2016-04-01

    In case of nuclear power plant accident, the assessment of the temporal evolution in the amount of radionuclides released (source term) is required to evaluate human health and environment impacts. It is with in mind that IRSN has developed an operational tool based on inverse modeling techniques to evaluate the source term of a radioactive release. If the release amount is sufficiently strong as for the Fukushima accident, dose rate observations are primarily used to assess the source term (Saunier et al. 2013). Secondly, air concentrations measurements can also be used when available. For minor release events, air concentrations measurements are used. Five years after the Fukushima accident, many estimations of the source term based on the use of observations in the environment have been published. There is not yet consensus on the magnitudes on the releases rates, mainly due to the high uncertainties on meteorological fields used to assess the source term. Within the framework of cooperation between IRSN and Meteorological Research Institute (MRI) of Japan Meteorological Agency (JMA), meteorological fields with higher spatial resolution (3 km) have been used (Sekiyama et al. 2013) to improve the simulation of the atmospheric dispersion from the Fukushima accident. Besides, new dataset of Cs137 atmospheric concentration obtained from the sampling tapes of the Suspended Particle Matter (SPM) monitoring network by the method of Tsuruta et al. (2014) are available. These data are very useful since several plumes, unknown until now, could be identified in addition with the two major plumes on March 15 and March 21. Therefore, the inverse modeling method has been applied to assess a new source term using Tsuruta air concentration measurements, dose rate measurements and meteorological fields provided by MRI. The simulations performed using this new inverted source term help enhance our knowledge about the Fukushima accident. Several releases events are better

  10. Concentration of trace elements, technogenic magnetic particles and charcoal in peat profiles as an evidence of thousands years of ore exploitation

    NASA Astrophysics Data System (ADS)

    Mendakiewicz, Maria; Magiera, Tadeusz; Szuszkiewicz, Marcin; Chróst, Leszek; Szopa, Sebastian

    2014-05-01

    The aim of the research is the geochemical and magnetic characteristic of peat bog profiles covered with a thin layer of fluvioglacial deposits appearing in the valley of the upper Brynica river (Upper Silesia, Poland). The research was supported with radiometric dating. The upper part of the Brynica basin has been the area of human activities since the Mesolithic through the Neolithic up to now, including intensive mining-smelting activities connected with the exploitation of Fe, Pb and Ag. In order to determine the geochemical composition a method of X-ray fluorescence (EDXRF) was used. The study revealed a high concentration of such chemical elements as Ag (at a depth of 15, 70, 80 and 95 cm), Cu (at a depth of 15 and 55 cm) as well as Pb and Sn (at a depth of 15 cm). The chemical pollution corresponds to the presence of technogenic magnetic particles (TMPs) in the peat bog profiles. The TMPs occur mainly in the form of iron and hydroxides of ferro- and ferrimagnetic properties and they come into existence during different high temperature technological processes. Their presence in the peat bog profiles as well as corresponding pollution together with charcoal suggest application of fire techniques to acquire metals from ore a few thousand years ago. MS2 Bartington meter with MS2B sensor was used to detect the TMPs and the age of the pollution was determined by the application of the radiocarbon method (C-14). The radiometric research was carried out in peat bog samples taken from the most polluted horizons and in charcoal particles separated from the profiles. The results of the dating indicate the highest concentration of pollution in peat bog profiles for the periods of 500 AD and 1200, 5500 as well as 9500 BC. The connection of geochemical and magnetic analyses used in the research appeared as an effective methods to detect and interpretation a trace evidence of human activities from a many thousand years in the past.

  11. Direct observation of solid-phase adsorbate concentration profile in powdered activated carbon particle to elucidate mechanism of high adsorption capacity on super-powdered activated carbon.

    PubMed

    Ando, Naoya; Matsui, Yoshihiko; Matsushita, Taku; Ohno, Koichi

    2011-01-01

    Decreasing the particle size of powdered activated carbon (PAC) by pulverization increases its adsorption capacities for natural organic matter (NOM) and polystyrene sulfonate (PSS, which is used as a model adsorbate). A shell adsorption mechanism in which NOM and PSS molecules do not completely penetrate the adsorbent particle and instead preferentially adsorb near the outer surface of the particle has been proposed as an explanation for this adsorption capacity increase. In this report, we present direct evidence to support the shell adsorption mechanism. PAC particles containing adsorbed PSS were sectioned with a focused ion beam, and the solid-phase PSS concentration profiles of the particle cross-sections were directly observed by means of field emission-scanning electron microscopy/energy-dispersive X-ray spectrometry (FE-SEM/EDXS). X-ray emission from sulfur, an index of PSS concentration, was higher in the shell region than in the inner region of the particles. The X-ray emission profile observed by EDXS did not agree completely with the solid-phase PSS concentration profile predicted by shell adsorption model analysis of the PSS isotherm data, but the observed and predicted profiles were not inconsistent when the analytical errors were considered. These EDXS results provide the first direct evidence that PSS is adsorbed mainly in the vicinity of the external surface of the PAC particles, and thus the results support the proposition that the increase in NOM and PSS adsorption capacity with decreasing particle size is due to the increase in external surface area on which the molecules can be adsorbed. PMID:20851447

  12. Soil concentrations and soil-air exchange of organochlorine pesticides along the Aba profile, east of the Tibetan Plateau, western China

    NASA Astrophysics Data System (ADS)

    Liu, Hongxia; Qi, Shihua; Yang, Dan; Hu, Ying; Li, Feng; Liu, Jia; Xing, Xinli

    2013-12-01

    Mianzhu—Aba profile, east of the Tibetan Plateau, was selected to study the occurrence of organochlorine pesticides (OCPs) along an altitudinal gradient. Dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs) and Aldrin, Dieldrin and Endrin (Drins) in surface soils were detected in winter (March) and summer (July). Soil concentrations (ng·g-1, dw) in winter and summer ranged as follws: DDTs, 0.37-179.16 and 0.32-42.57; HCHs, 0.14-10.76 and 0.55-32.71; Drins, N.D-3.99 and 0.02-6.93, respectively. Main soil OCPs were p, p'-DDT, p, p'-DDE, β-HCH and Drins, among which Drins were rarely reported in current literature of the Tibetan Plateau. Higher OCP concentrations in the profile were attributed close to the agricultural fields of the Sichuan Basin, current lindane and nondicofol DDTs inputs, and also long-range atmospheric transport from abroad. Soil OCP concentrations underwent obvious seasonal variation, with higher DDTs in winter and higher HCHs and Drins in summer. It may be caused by climatic conditions, summer monsoon type, and physico-chemical properties of such contaminants. Though "rest" phenomenon occurred in some sampling sites, HCHs and Drins showed an increasing trend with increasing altitude, while DDTs showed an evident decrease with increasing altitude. The altitudinal distributions of OCPs were all consistent with previous findings in other mountainous regions. A primary fugacity analysis on OCPs soil-air exchange indicated that the profile may be secondary sources for HCHs and Endrin. As with Aldrin, Dieldrin, and DDTs, the profile may be both secondary sources and sinks.

  13. Differences in the metabolite profiles of spinach (Spinacia oleracea L.) leaf in different concentrations of nitrate in the culture solution.

    PubMed

    Okazaki, Keiki; Oka, Norikuni; Shinano, Takuro; Osaki, Mitsuru; Takebe, Masako

    2008-02-01

    The nitrogen (N) status of a plant determines the composition of its major components (amino acids, proteins, carbohydrates and organic acids) and, directly or indirectly, affects the quality of agricultural products in terms of their calorific value and taste. Although these effects are guided by changes in metabolic pathways, no overall metabolic analysis has previously been conducted to demonstrate such effects. Here, metabolite profiling using gas chromatography-mass spectrometry (GC-MS) was used to evaluate the effect of N levels on spinach tissue, comparing two cultivars that differed in their ability to use N. Wide variation in N content was observed without any distinct inhibition of growth in either cultivar. Principal component analysis (PCA) and self-organizing mapping (SOM) were undertaken to describe changes in the metabolites of mature spinach leaves. In PCA, the first component accounted for 44.5% of the total variance, the scores of which was positively correlated with the plant's N content, and a close relationship between metabolite profiles and N status was observed. Both PCA and SOM revealed that metabolites could be broadly divided into two types, correlating either positively or negatively with plant N content. The simple and co-coordinated metabolic stream, containing both general and spinach-specific aspects of plant N content, will be useful in future research on such topics as the detection of environmental effects on spinach through comprehensive metabolic profiling. PMID:18089581

  14. Cardiovascular disease risk profile among young Saudi women of Al-Qassim, Saudi Arabia: A cross-sectional study

    PubMed Central

    Kalaf, Hassan; AlMesned, Abdulrahman; Soomro, Tark; Lasheen, Wael; Ewid, Mohamed; Al-Mohaimeed, Abdulrahman A

    2016-01-01

    Study Objective The aim of the study was to assess the level of risk for cardiovascular diseases (CVD) among young Saudi women living in Al-Qassim, Saudi Arabia. Methods As part of “The Heart Protection Campaign” in the Al-Qassim region, data were collected from Saudi women using questionnaires as well as objective measurement of height, weight, blood pressure, and blood glucose. Data were analyzed using descriptive statistics. Results Only 15% of the sample were free of risk factors, the majority had either one (57.5%) or two (20.8%) risk factors. Additionally, 6.7% were considered to be at high-risk with three or more risk factors. The most common risk factors were physical inactivity (74%) and overweight/obesity, (25%/29%). There was a significant increase in the number of risk factors across age groups. Women over the age of 30 were more likely to have a higher number of risk factors than the younger women (20–24 years). Conclusions Young women in Al-Qassim, Saudi Arabia have an unusually high risk for CVD. Since the number of risk factors increases substantially between the ages of 20 and 35, there is a need to develop prevention programs to lower the CVD risk through diet and exercise. PMID:27004055

  15. Radiation performance of AlGaAs and InGaAs concentrator cells and expected performance of cascade structures

    NASA Technical Reports Server (NTRS)

    Curtis, H. B.; Swartz, C. K.; Hart, R. E., Jr.

    1987-01-01

    Aluminum gallium arsenide, GaAs, silicon and InGaAs cells have been irradiated with 1-MeV electrons and 37-MeV protons. These cells are candidates for individual cells in a cascade structure. Data are presented for both electron and proton irradiation studies for one sun and a concentration level of 100X AM0. Results of calculations on the radiation resistance of cascade cell structures based on the individual cell data are also presented. Both series-connected and separately connected structures are investigated.

  16. Sorghum Germplasm Profiling to Assist Breeding and Gene Identification for Biofortification of Grain Mineral and Protein Concentrations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sorghum (Sorghum bicolor) is the world’s fifth most important grain crop, and is a widely consumed staple in subtropical semi-arid regions of Africa and Asia. Biofortification of sorghum by increasing mineral micronutrient (especially iron and zinc) and protein concentration is of widespread intere...

  17. Dissolved Oxygen Concentration Profiles in the Hyporheic Zone Through the Use of a High-Density Fiber Optic Measurement Network

    NASA Astrophysics Data System (ADS)

    Reeder, William Jeffrey; Quick, Annika; Farrell, Tiffany B.; Benner, Shawn G.; Feris, Kevin P.; Tonina, Daniele

    2015-04-01

    The majority of chemical reactions in riverine systems occur within the hyporheic zone (HZ). Hyporheic exchange, flow into and out of the hyporheic zone, represents a primary control over those reactions because the flow rate will determine the residence time and amount of chemical constituents in the HZ. Hyporheic flow can be conceptualized as discreet streamlines that collectively represent a broad distribution of residence times. Within this context, dissolved oxygen (DO) concentration becomes a primary indicator of the redox and biochemical state of the HZ including, for example, the fate of carbon, contaminant behavior, nutrient cycling, stream DO levels and nitrous oxide (N2O) production. River systems have been identified as a significant source of N2O emissions, contributing an estimated 10% of anthropogenically generated N2O. The primary biochemical transformations that lead to N2O production are nitrification (NH4+ to NO3-) and denitrification (NO3- to N2) reactions that are mediated by microbes living in the HZ. Current theory describes a process in which DO enters the stoss side of the HZ and is consumed by respiration and nitrification in the upstream, oxic portion of the streamlines leading to a progressive partitioning of the HZ from oxic to anoxic. This conceptualization, however, has not been well validated in a physical sense, due to inherent difficulties associated with measuring chemical concentrations in the HZ. To test current theory, we measured HZ DO concentrations, in a large-scale flume experiment, almost continuously for five months using a multiplexed optical network and a precision robotic surface probe system. We were able to measure DO at higher spatial and temporal resolution than has been previously demonstrated. These measurements, coupled with detailed numerical modeling of HZ flowlines, allowed us to map HZ DO concentrations spatially and over time. Our findings validate the models that describe the consumption of DO through

  18. Effects of brine concentration on lipid oxidation and fatty acids profile of hot smoked tuna ( Thunnus albacares ) stored at refrigerated temperature.

    PubMed

    Guizani, Nejib; Rahman, Mohammad Shafiur; Al-Ruzeiqi, Mohamed Hamad; Al-Sabahi, Jamal Nasser; Sureshchandran, Sithara

    2014-03-01

    This work evaluated the lipid oxidation and the changes in fatty acids in hot-smoked tuna (Thunnus albacares) as a function of brine concentration. Fresh, commercially harvested tuna fish samples were purchased from a local supermarket. The fish were first immersed for 30 min in a brine solution at 5, 10, or 15% sodium chloride concentration and were then smoked at 50 °C for 3 h followed by 1 h at 60 °C and 3 h at 105 °C. The fish were then dried for 17 h, cooled and stored at 4 °C. Oxidative rancidity was measured by the peroxide value (PV), and thiobarbituric acid number (TBA) and fatty acids profile by GC-MS. Oxidative rancidity increased with storage time. The PV and TBARS values were more pronounced for samples immersed in 10% brine solution during the first 27 days of storage, whereas the lowest increase was observed for samples treated with 15% salt. Fatty acid concentration exhibited changes after smoking, and this was varied with salt concentration. The palmitic acid and stearic acid, the two main saturated fatty acids in tuna, increased after smoking at all brine concentration, whereas the contents of oleic acid, eicosapentaenoic acid and docosahexaenoic acid decreased. In conclusion, 15% NaCl-treated tuna gave smoked product with less lipid oxidation and a fatty acid profile comparable to that for 5 and 10% NaCl-treated samples. PMID:24587535

  19. Effect of cerium addition on casting/chill interfacial heat flux and casting surface profile during solidification of Al-14%Si alloy

    NASA Astrophysics Data System (ADS)

    Vijeesh, V.; Prabhu, K. N.

    2016-03-01

    In the present investigation, Al-14 wt. % Si alloy was solidified against copper, brass and cast iron chills, to study the effect of Ce melt treatment on casting/chill interfacial heat flux transients and casting surface profile. The heat flux across the casting/chill interface was estimated using inverse modelling technique. On addition of 1.5% Ce, the peak heat flux increased by about 38%, 42% and 43% for copper, brass and cast iron chills respectively. The effect of Ce addition on casting surface texture was analyzed using a surface profilometer. The surface profile of the casting and the chill surfaces clearly indicated the formation of an air gap at the periphery of the casting. The arithmetic average value of the profile departure from the mean line (Ra) and arithmetical mean of the absolute departures of the waviness profile from the centre line (Wa) were found to decrease on Ce addition. The interfacial gap width formed for the unmodified and Ce treated casting surfaces at the periphery were found to be about 35µm and 13µm respectively. The enhancement in heat transfer on addition of Ce addition was attributed to the lowering of the surface tension of the liquid melt. The gap width at the interface was used to determine the variation of heat transfer coefficient (HTC) across the chill surface after the formation of stable solid shell. It was found that the HTC decreased along the radial direction for copper and brass chills and increased along radial direction for cast iron chills.

  20. Mineral content of grasses and grasslands of the Himalayan region: 1. Trace element distribution in soil profiles and their concentrations in surface soils

    SciTech Connect

    Singh, B.R.; Mishra, V.K.; Tripathi, B.R.

    1987-03-01

    Researchers analyzed soil samples, collected from naturally occurring grasslands of the Himalayan region, to investigate trace element distribution in soil profiles and their concentrations in surface soils, as well as to examine frequency and geographical distribution of low and high levels of trace elements. Both chemical and radiochemical analytical techniques were employed to determine the trace elements. This study was part of a research project on the evaluation of mineral content of natural grasslands and grasses and the relationship between the mineral contents in grasses and grasslands. Little or no variation in the content of total Zn, Mn, Cu, Cd, Ni, Pb, Co, and I from surface to subsurface horizons in the soil profiles was observed. However, the concentrations of extractable Zn, Mn, Cu, and B in the surface horizons were higher than in the subsurface horizons. The variations among the profiles were primarily related to the geological material from which the soils derived. Means and ranges of trace elements are given for particular locations and for the whole sample area. Concentrations of most of the trace elements varied greatly among sites at the same location and among locations. There were highly significant correlations between the contents of trace elements, especially total Zn and Mn, and extractable Zn, Fe, Ni, Co, B, and I, and the soil chemical properties, elevation, rainfall, and temperature. Rainfall and temperature showed negative correlations for almost all the trace elements. A number of the trace elements were interrelated in their geochemical origin. On the basis of the critical levels suggested for trace element deficiencies, proportions of the samples that may be considered deficient were about 28% for Zn, 50% for Mn, 20-30% for Cu, 4% for Fe, 56-87% for B, 77% for Mo, and 5-10% for Co.

  1. A Case Study on Observed and Simulated CO2 Concentration Profiles in Hefei based on Raman Lidar and GEOS-Chem Model

    NASA Astrophysics Data System (ADS)

    Wang, Yinan; Lü, Daren; Pan, Weilin; Yuan, Kee

    2016-06-01

    Observations of atmospheric CO2 concentration profiles provide significative constraints on the global/regional inversions of carbon sources and sinks. Anhui Institute of Optics and Fine Mechanics of Chinese Academy of Sciences developed a Raman Lidar system to detect the vertical distribution of atmospheric CO2. This paper compared the observations with the modeled results from a three-dimensional global chemistry transport model-GEOS-Chem, which showed a good agreement in the trend of change with lidar measurements. The case study indicated a potential for better simulating vertical distribution of atmospheric CO2 by combining with lidar measurements.

  2. Activity concentration and spatial distribution of radionuclides in marine sediments close to the estuary of Shatt al-Arab/Arvand Rud River, the Gulf.

    PubMed

    Patiris, D L; Tsabaris, C; Anagnostou, C L; Androulakaki, E G; Pappa, F K; Eleftheriou, G; Sgouros, G

    2016-06-01

    Tigris and Euphrates rivers both emerge in eastern Turkey and cross Syria and Iraq. They unite to Shatt al-Arab/Arvand Rud River and discharge in Arabic/Persian Gulf. The activity concentration of natural and anthropogenic radionuclides was measured during the August of 2011 in a number of surficial sediment samples collected from the seabed along an almost straight line beginning near the estuary mouth and extending seaward. The results exhibited low activity concentration levels and an almost homogeneous spatial distribution except locations where sediment of biogenic origin, poor in radionuclides, dilute their concentrations. Dose rates absorbed by reference marine biota were calculated by the ERICA Assessment Tool considering the contribution of 40 K. The results revealed a relatively low impact of 40 K mainly to species living in, on and close to the seabed. Also, statistical association of radionuclides with selected stable elements (Ca, Ba and Sr) did not indicate presence of by-products related with oil and gas exploitation and transportation activities. Moreover, a semi-empirical sedimentology model applied to reproduce seabed granulometric facies based entirely on radionuclides activity concentrations. PMID:26945883

  3. Quantitative determination of erosion rates in humid region using depth profiles of in situ-produced Be-10 and Al-26

    NASA Astrophysics Data System (ADS)

    Nakamura, A.; Yokoyama, Y.; Miyairi, Y.; Shiroya, K.; Matsuzaki, H.; Suzuki, A.

    2012-12-01

    Determination of erosion rates is important across a diverse range of disciplines in geology, geomorphology, and biogeochemistry (Granger and Riebe, 2007). Yet rates of long-term erosion have been difficult to quantify until recently. Measurements of in-situ produced terrestrial cosmogenic nuclides (TCN) allow us to understand earth surface process quantitatively (Goss and Phillips, 2001) and has been successfully used to provide erosion rates of bedrock in arid regions where negligible or small erosion process is being taken place (e.g. Cockburn et al., 1999). Environmental parameters such as mean annual precipitation have been used to explain erosion rate variability on a global scale (Bierman and Cafee, 2002). However, the relationship between erosion rates and precipitation is still under debate due in part to scarcity of data from higher mean annual precipitation regions. In addition, erosion rates deduced from drainage basins, which is the only method to quantify erosion rates in humid regions, are strongly affected by steepness of basin slope (Riebe et al., 2000). Therefore, different approach to determine the erosion rates in humid regions is required to corroborate findings from arid regions. Here we present depth profiles of in situ-produced 10Be and 26Al on hilltop sites of Japan. The contribution from unique characteristics of individual basin slope should be minimized since all sites are limited on top of the hill, allowing a direct comparison to studies of bedrock erosion rates in arid regions. The aims of this study are (1) to develop a model of TCN depth profiles, based on actually measured density in granitic saprolite, and (2) to assess climate control on erosion rates. These data indicate close linkage between earth surface process and climate. A discrepancy in the theoretical value is also observed from the depth profiles in Saga prefecture, Japan, which may support the potential of obtaining non-steady erosion process through glacial

  4. Update to modeling soil selenium concentrations in the shallow soil profile at Kesterson Reservoir Merced County, California

    SciTech Connect

    Wahl, C.; Benson, S.M.

    1996-01-01

    A mass balance model was developed to predict concentrations of water-extractable selenium in surface and subsurface soil by extrapolating the trend observed from 6 years of soil monitoring data collected at Kesterson Reservoir. Correlations between observed and calculated concentrations indicate that the major trends and year-to-year variations are well represented with the model. Results from this exercise were then used, under three climatic scenarios, to simulate the evolution of the soluble selenium inventory 25 years into the future. Based on these simulations, we expect that the availability of the soluble selenium inventory has most likely reached peak levels, and is now declining. However, year-to-year climatic variations may influence the rate of decline, and occasionally reverse this prevailing trend.

  5. Profile and relative concentrations of fatty acids in corn and soybean seeds from transgenic and isogenic crops.

    PubMed

    Jiménez, J J; Bernal, J L; Nozal, M J; Toribio, L; Bernal, J

    2009-10-23

    In this work 44 fatty acids, which were analyzed as methyl esters by GC/MS in scan mode, have been determined in genetically modified corn and soybean seeds. Their relative concentrations have been compared with those of isogenic lines grown in the same conditions. Studied compounds comprised saturated and unsaturated fatty acids, including cis/trans isomers and minor fatty acids. A classical soxhlet extraction and an accelerated solvent extraction have been assayed to extract the fatty compounds from seeds and the GC separation has been carried out on a biscyanopropylpolysiloxane chromatographic column. Soxhlet extraction was selected as the most convenient and applied to compare the samples. Specific compounds, which could denote the origin of the crop have not been observed, but for some sample pairs, significant differences have been found in relation to the percentage of certain acids; the highest differences for major acids were 4.1% in corn and 4.8% in soybean. The concentrations of long chain acids such as 24:0, 26:0 and 28:0 were higher in some isogenic lines whereas the concentrations of short chain acids such as 6:0, 8:0, 9:0, 10:0 and 12:0 were higher in their transgenic counterparts. PMID:19716136

  6. Soil concentration profiles and diffusion and emission of nitrous oxide influenced by the application of biochar in a rice-wheat annual rotation system.

    PubMed

    Zhou, Ziqiang; Xu, Xin; Bi, Zhichao; Li, Lu; Li, Bo; Xiong, Zhengqin

    2016-04-01

    Field experiments were carried out to determine biochar effects on nitrous oxide (N2O) concentration profiles, diffusion, and emissions in paddy soil under rice-wheat annual rotation in southeastern China. An in situ soil gas device was adapted to measure N2O concentrations at depths of 7, 15, 30, and 50 cm. Five treatments were installed as N0B0, N0B1, N1B0, N1B1, and N1B2 (B0, B1, and B2 designated as biochar at 0, 20, and 40 t ha(-1), respectively, while N0 and N1 as nitrogen at 0 and 250 kg N ha(-1) crop(-1), respectively). The results showed that N2O concentrations were higher in the 15 and 30 cm depths than other depths. With positive diffusive fluxes, the 7 cm in the rice season and 15 cm in the wheat season were main production sites. The surface N2O emissions and topsoil diffusive fluxes showed good agreement. N application strongly increased soil N2O profiles and surface emissions. Relative to N1B0, N1B1 decreased N2O concentration, surface emissions, and diffusive fluxes by 25.2, 31.8, and 26.5 %, respectively, while N1B2 decreased them averagely by 40.7, 43.2, and 44.2 %, correspondingly. Therefore, the gas gradient method is effective for estimating N2O emissions, and biochar can decrease N2O production when N was applied. PMID:26769480

  7. Profiling patterns of fecal 20-oxopregnane concentrations during ovarian cycles in free-ranging southern white rhinoceros (Ceratotherium simum simum).

    PubMed

    van der Goot, Annemieke Catharina; Martin, Graeme Bruce; Millar, Robert Peter; Paris, Monique Christina Johanna; Ganswindt, Andre

    2015-10-01

    Unlike their wild counterparts, many white rhinoceros females in captivity fail to reproduce successfully such that current captive populations are not self-sustaining. The causes of the problem are poorly understood. Variation in cycle length and long periods of acyclicity are characteristics of the majority of these non-reproducing females in captivity but it is unknown whether these characteristics are a feature of reproductively successful free-ranging females. This study therefore aimed to monitor cyclic activity in a wild population of southern white rhinoceros at Lapalala Wilderness, South Africa, by measuring the concentrations of immunoreactive fecal progestagen metabolites (fPM). Five adult females were tracked twice per week for 20 months and if located a fresh fecal sample was collected. Reproductive events and group structural dynamics were also recorded and subsequently correlated with the fPM data. The baseline concentration of fPM was 0.69±0.20μg/g DW while concentrations during pregnancy were 30-400-fold higher. The females exhibited estrous cycle lengths of 30.6±7.7 days and, based on fPM data, gestation length in one female was 502±3 days. Year-round monitoring showed no clear evidence of seasonality in ovarian activity. During cyclic luteal activity females were often seen in the presence of a dominant bull. One female stopped cycling after removal of the local dominant bull and luteal activity only returned after a new bull was introduced. This suggests that white rhinoceros females in the wild might need external stimuli from a male to ovulate. These findings indicate that the irregular cyclicity reported for white rhinoceros housed in zoos and animal parks may result from conditions in captivity and account for reduced fertility. PMID:26372226

  8. Elevated plasma and urinary concentrations of green tea catechins associated with improved plasma lipid profile in healthy Japanese women.

    PubMed

    Takechi, Ryusuke; Alfonso, Helman; Hiramatsu, Naoko; Ishisaka, Akari; Tanaka, Akira; Tan, La'Belle; Lee, Andy H

    2016-03-01

    This study investigated green tea catechins in plasma and urine and chronic disease biomarkers. We hypothesized that plasma and urinary concentration of green tea catechins are associated with cardiovascular disease and diabetes biomarkers. First void urine and fasting plasma samples were collected from 57 generally healthy females aged 38 to 73 years (mean, 52 ± 8 years) recruited in Himeji, Japan. The concentrations of plasma and urinary green tea catechins were determined by liquid chromatography coupled with mass tandem spectrometer. Low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglyceride, glucose, insulin, glycated hemoglobin, and C-reactive protein in plasma/serum samples were analyzed by a commercial diagnostic laboratory. Statistical associations were assessed using Spearman correlation coefficients. The results showed weak associations between plasma total catechin and triglyceride (r = -0.30) and LDL cholesterol (r = -0.28), whereas plasma (-)-epigallocatechin-3-gallate, (-)-epigallocatechin, (-)-epicatechin-3-gallate, and (-)-epicatechin exhibited weak to moderate associations with triglyceride or LDL cholesterol, but little associations with HDL cholesterol, body fat, and body mass index were evident. Urinary total catechin was weakly associated with triglyceride (r = -0.19) and LDL cholesterol (r = -0.15), whereas urinary (-)-epigallocatechin-3-gallate (r = -0.33), (-)-epigallocatechin (r = -0.23), and (-)-epicatechin-3-gallate (r = -0.33) had weak to moderate correlations with triglyceride and similarly with body fat and body mass index. Both plasma (r = -0.24) and urinary (r = -0.24) total catechin, as well as individual catechins, were weakly associated with glycated hemoglobin. Plasma total and individual catechins were weakly to moderately associated with C-reactive protein, but not the case for urinary catechins. In conclusion, we found weak to moderate associations between plasma and urinary green tea

  9. Depth profiles of temperature, specific conductance and oxygen concentration in Lake Powell, Arizona-Utah, 1992-95

    USGS Publications Warehouse

    Marzolf, G. Richard; Hart, Robert J.; Stephens, Doyle W.

    1998-01-01

    The depth distribution of temperature in lakes and reservoirs establishes vertical-density gradients that regulate the distribution of a wide array of chemical and biological features. In Lake Powell, the depth at which inflowing river water enters the reservoir is controlled by the water temperature of the river compared to the vertical-thermal structure of the reservoir in late spring and early summer. The measurements reported here document the longitudinal and vertical pattern of temperature, specific conductance, and oxygen concentration on several dates in 1992, 1994, and 1995.

  10. CO2 and CH4 Surface Flux, Soil Profile Concentrations, and Stable Isotope Composition, Barrow, Alaska, 2012-2013

    DOE Data Explorer

    Curtis, J.B.; Vaughn, L.S.; Torn, M.S.; Conrad, M.S.; Chafe, O.; Bill, M.

    2015-12-31

    In August-October 2012 and June-October 2013, co-located measurements were made of surface CH4 and CO2 flux, soil pore space concentrations and stable isotope compositions of CH4 and CO2, and subsurface temperature and soil moisture. Measurements were made in intensive study site 1 areas A, B, and C, and from the site 0 and AB transects, from high-centered, flat-centered, and low-centered polygons, from the center, edge, and trough of each polygon.

  11. Solar-flare implanted He-4/He-3 and solar-proton-produced NE and AR concentration profiles preserved in lunar rock 61016

    NASA Astrophysics Data System (ADS)

    Rao, M. N.; Garrison, D. H.; Bogard, D. D.; Reedy, R. C.

    1993-05-01

    Depth profiles for Ne-21, Ne-22, and Ar-38 isotopes from oriented lunar rock 61016 are reported. Concentration profiles of cosmogenic GCR+SCR (Galactic cosmic ray and solar cosmic ray-produced) isotopes are determined, quantitatively resolving neon and argon produced by energetic solar flares from that produced by Galactic cosmic rays. The SCR component is resolved from the GCR component as a function of shielding, and excellent agreement is found between experimental SCR production profiles for the isotopes and theoretically calculated values. A characteristic SW He-4/He-3 ratio of 3450 +/- 81, representing energies down to as few keV/amu. In slightly deeper samples an SRF He-4/He-3 ratio of 3450 +/- 725 is found for He particles with E larger than about 1 MeV/amu. These results indicate that the isotopic composition of SF He, averaged over the long term, is energy-dependent. An implanted Ne-20/Ne-22 ratio of 12.4 is measured in unetched samples, representing E greater than 1 MeV/amu, and a ratio of 11.6 is inferred in the samples, representing E larger than about 5 MeV/amu.

  12. Solar-flare implanted He-4/He-3 and solar-proton-produced Ne and Ar concentration profiles preserved in lunar rock 61016

    NASA Technical Reports Server (NTRS)

    Rao, M. N.; Garrison, D. H.; Bogard, D. D.; Reedy, R. C.

    1993-01-01

    Depth profiles for Ne-21, Ne-22, and Ar-38 isotopes from oriented lunar rock 61016 are reported. Concentration profiles of cosmogenic GCR+SCR (Galactic cosmic ray and solar cosmic ray-produced) isotopes are determined, quantitatively resolving neon and argon produced by energetic solar flares from that produced by Galactic cosmic rays. The SCR component is resolved from the GCR component as a function of shielding, and excellent agreement is found between experimental SCR production profiles for the isotopes and theoretically calculated values. A characteristic SW He-4/He-3 ratio of 3450 +/- 81, representing energies down to as few keV/amu. In slightly deeper samples an SRF He-4/He-3 ratio of 3450 +/- 725 is found for He particles with E larger than about 1 MeV/amu. These results indicate that the isotopic composition of SF He, averaged over the long term, is energy-dependent. An implanted Ne-20/Ne-22 ratio of 12.4 is measured in unetched samples, representing E greater than 1 MeV/amu, and a ratio of 11.6 is inferred in the samples, representing E larger than about 5 MeV/amu.

  13. Impact of exposure to low concentrations of nitric oxide on protein profile in murine and human pancreatic islet cells

    PubMed Central

    Tapia-Limonchi, Rafael; Díaz, Irene; Cahuana, Gladys M; Bautista, Mario; Martín, Franz; Soria, Bernat; Tejedo, Juan R; Bedoya, Francisco J

    2014-01-01

    Homeostatic levels of nitric oxide (NO) protect efficiently against apoptotic death in both human and rodent pancreatic β cells, but the protein profile of this action remains to be determined. We have applied a 2 dimensional LC-MS-MALDI-TOF/TOF-based analysis to study the impact of protective NO in rat insulin-producing RINm5F cell line and in mouse and human pancreatic islets (HPI) exposed to serum deprivation condition. 24 proteins in RINm5F and 22 in HPI were identified to undergo changes in at least one experimental condition. These include stress response mitochondrial proteins (UQCRC2, VDAC1, ATP5C1, ATP5A1) in RINm5F cells and stress response endoplasmic reticulum proteins (HSPA5, PDIA6, VCP, GANAB) in HPI. In addition, metabolic and structural proteins, oxidoreductases and chaperones related with protein metabolism are also regulated by NO treatment. Network analysis of differentially expressed proteins shows their interaction in glucocorticoid receptor and NRF2-mediated oxidative stress response pathways and eNOS signaling. The results indicate that exposure to exogenous NO counteracts the impact of serum deprivation on pancreatic β cell proteome. Species differences in the proteins involved are apparent. PMID:25658244

  14. Developments in the SediView Technique for the processing of ADCP backscatter data to extract suspended sediment concentration profiles in flocculated sediments

    NASA Astrophysics Data System (ADS)

    Taylor, Jon; Manning, Andrew; Crossouard, Neil

    2014-05-01

    From its appearance in the 1980's researchers have recognised the possibilities offered by Acoustic Doppler Current Profiler's (ADCP's) as a means of obtaining information on fluid motion and concentration profiles in both muddy and sandy environments. To date much research effort has been directed in using ADCP's to indirectly observe variations in sandy sediments in suspension using the intensity of the backscattered energy returned from an ADCP and indeed to applications involving mixed suspensions of Sandy and Silty sediments. Studies of naturally flocculating sediment suspensions have however been limited due to practical difficulties in obtaining measurements of floc properties and the incomplete understanding of the interaction taking place between high frequency sound waves and the flocculated particles whilst those that are available have tended to be based on academic studies utilising multi-frequency acoustic sensors rather than the more ubiquitous Acoustic Doppler profilers used in commercial marine monitoring applications and hence their findings are limited in their application. In response to the need to provide water column concentration estimates for engineering applications the Sediview™ method was developed as a means of analysing acoustic backscatter data collected using standard ADCP profilers by means of a robust field methodology supported by software tools and the approach been applied to datasets collected in estuarine and fluvial environments worldwide through it's application on dredging and maritime engineering projects. The poster describes the application of Sediview™ methodology to the application of determining sediment concentration estimates from flocculated sediments measured at a site located within the Turbidity Maximum Zone of the Thames Estuary, UK, and in particular the application of a dual frequency approach to the problem. The experimental investigations described focused on the Acoustic backscatter from ADCPs

  15. Constraining Dark Matter Halo Profiles and Galaxy Formation Models Using Spiral Arm Morphology. II. Dark and Stellar Mass Concentrations for 13 Nearby Face-on Galaxies

    NASA Astrophysics Data System (ADS)

    Seigar, Marc S.; Davis, Benjamin L.; Berrier, Joel; Kennefick, Daniel

    2014-11-01

    We investigate the use of spiral arm pitch angles as a probe of disk galaxy mass profiles. We confirm our previous result that spiral arm pitch angles (P) are well correlated with the rate of shear (S) in disk galaxy rotation curves. We use this correlation to argue that imaging data alone can provide a powerful probe of galactic mass distributions out to large look-back times. We then use a sample of 13 galaxies, with Spitzer 3.6 μm imaging data and observed Hα rotation curves, to demonstrate how an inferred shear rate coupled with a bulge-disk decomposition model and a Tully-Fisher-derived velocity normalization can be used to place constraints on a galaxy's baryon fraction and dark matter halo profile. Finally, we show that there appears to be a trend (albeit a weak correlation) between spiral arm pitch angle and halo concentration. We discuss implications for the suggested link between supermassive black hole (SMBH) mass and dark halo concentration, using pitch angle as a proxy for SMBH mass.

  16. Constraining dark matter halo profiles and galaxy formation models using spiral arm morphology. II. Dark and stellar mass concentrations for 13 nearby face-on galaxies

    SciTech Connect

    Seigar, Marc S.; Davis, Benjamin L.; Berrier, Joel; Kennefick, Daniel

    2014-11-01

    We investigate the use of spiral arm pitch angles as a probe of disk galaxy mass profiles. We confirm our previous result that spiral arm pitch angles (P) are well correlated with the rate of shear (S) in disk galaxy rotation curves. We use this correlation to argue that imaging data alone can provide a powerful probe of galactic mass distributions out to large look-back times. We then use a sample of 13 galaxies, with Spitzer 3.6 μm imaging data and observed Hα rotation curves, to demonstrate how an inferred shear rate coupled with a bulge-disk decomposition model and a Tully-Fisher-derived velocity normalization can be used to place constraints on a galaxy's baryon fraction and dark matter halo profile. Finally, we show that there appears to be a trend (albeit a weak correlation) between spiral arm pitch angle and halo concentration. We discuss implications for the suggested link between supermassive black hole (SMBH) mass and dark halo concentration, using pitch angle as a proxy for SMBH mass.

  17. Effect of oral mineral and energy supplementation on blood mineral concentrations, energetic and inflammatory profile, and milk yield in dairy cows affected with dystocia.

    PubMed

    Benzaquen, M; Galvão, K N; Coleman, A E; Santos, J E P; Goff, J P; Risco, C A

    2015-05-01

    The objectives of this study were to determine the effect of mineral/energy supplementation of dairy cows with dystocia on blood mineral concentrations, energetic and inflammatory profiles, and milk yield. Multiparous Holstein cows with dystocia were randomly assigned into two groups, (1) treated with a mineral/energy supplement (DME, n= 18) and (2) not treated (DNT, n= 22). A group of cows with normal parturition were randomly selected and were left untreated (NNT, n= 25). Cows in DME received an oral drench of 110 g of calcium and 400 g of propionate as calcium propionate plus 110 g potassium chloride and 150 g of magnesium sulfate administered within 6 h of calving and again 3 days post-partum. Compared to cows with a normal parturition, dystocic cows had decreased plasma calcium concentrations, increased plasma haptoglobin, decreased milk yield at 1 day post-partum, and tended to have increased rectal temperatures from 1 to 12 days post-partum. Compared with cows in DNT, those in DME had decreased plasma calcium concentrations and increased plasma magnesium concentrations 2 and 3 days post-partum, and a tendency for an increase in rectal temperature from 1 to 12 days post-partum. Dystocia is detrimental to calcium homeostasis post-partum, but mineral/energy supplementation as undertaken in this study is not recommended for use in cows with dystocia. PMID:25900193

  18. New procyanidin B3-human salivary protein complexes by mass spectrometry. Effect of salivary protein profile, tannin concentration, and time stability.

    PubMed

    Perez-Gregorio, Maria Rosa; Mateus, Nuno; De Freitas, Victor

    2014-10-15

    Several factors could influence the tannin-protein interaction such as the human salivary protein profile, the tannin tested, and the tannin/protein ratio. The goal of this study aims to study the effect of different salivas (A, B, and C) and different tannin concentrations (0.5 and 1 mg/mL) on the interaction process as well as the complex's stability over time. This study is focused on the identification of new procyanidin B3-human salivary protein complexes. Thus, 48 major B3-human salivary protein aggregates were identified regardless of the saliva and tannin concentration tested. A higher number of aggregates was found at lower tannin concentration. Moreover, the number of protein moieties involved in the aggregation process was higher when the tannin concentration was also higher. The selectivity of the different groups of proteins to bind tannin was also confirmed. It was also verified that the B3-human salivary protein complexes formed evolved over time. PMID:25248720

  19. In situ strain profiling of elastoplastic bending in Ti-6Al-4V alloy by synchrotron energy dispersive x-ray diffraction

    SciTech Connect

    Croft, M.; Shukla, V.; Akdogan, E. K.; Sadangi, R.; Ignatov, A.; Balarinni, L.; Tsakalakos, T.; Jisrawi, N.; Zhong, Z.; Horvath, K.

    2009-05-01

    Elastic and plastic strain evolution under four-point bending has been studied by synchrotron energy dispersive x-ray diffraction. Measured strain profiles across the specimen thickness showed an increasing linear elastic strain gradient under increasing four-point bending load up to approx2 kN. The bulk elastic modulus of Ti-6Al-4V was determined as 118 GPa. The onset of plastic deformation was found to set in at a total in-plane strain of approx0.008, both under tension and compression. Plastic deformation under bending is initiated in the vicinity of the surface and at a stress of 1100 MPa, and propagates inward, while a finite core region remains elastically deformed up to 3.67 kN loading. The onset of the plastic regime and the plastic regime itself has been verified by monitoring the line broadening of the (100) peak of alpha-Ti. The effective compression/tension stress-strain curve has been obtained from the scaling collapse of strain profile data taken at seven external load levels. A similar multiple load scaling collapse of the plastic strain variation has also been obtained. The level of precision in strain measurement reported herein was evaluated and found to be 1.5x10{sup -5} or better.

  20. Atomic-resolved depth profile of strain and cation intermixing around LaAlO3/SrTiO3 interfaces.

    PubMed

    Zaid, H; Berger, M H; Jalabert, D; Walls, M; Akrobetu, R; Fongkaew, I; Lambrecht, W R L; Goble, N J; Gao, X P A; Berger, P; Sehirlioglu, A

    2016-01-01

    Novel behavior has been observed at the interface of LaAlO3/SrTiO3 heterostructures such as two dimensional metallic conductivity, magnetic scattering and superconductivity. However, both the origins and quantification of such behavior have been complicated due to an interplay of mechanical, chemical and electronic factors. Here chemical and strain profiles near the interface of LaAlO3/SrTiO3 heterostructures are correlated. Conductive and insulating samples have been processed, with thicknesses respectively above and below the commonly admitted conductivity threshold. The intermixing and structural distortions within the crystal lattice have been quantitatively measured near the interface with a depth resolution of unit cell size. A strong link between intermixing and structural distortions at such interfaces is highlighted: intermixing was more pronounced in the hetero-couple with conductive interface, whereas in-plane compressive strains extended deeper within the substrate of the hetero-couple with the insulating interface. This allows a better understanding of the interface local mechanisms leading to the conductivity. PMID:27301609

  1. Atomic-resolved depth profile of strain and cation intermixing around LaAlO3/SrTiO3 interfaces

    PubMed Central

    Zaid, H.; Berger, M. H.; Jalabert, D.; Walls, M.; Akrobetu, R.; Fongkaew, I.; Lambrecht, W. R. L.; Goble, N. J.; Gao, X. P. A.; Berger, P.; Sehirlioglu, A.

    2016-01-01

    Novel behavior has been observed at the interface of LaAlO3/SrTiO3 heterostructures such as two dimensional metallic conductivity, magnetic scattering and superconductivity. However, both the origins and quantification of such behavior have been complicated due to an interplay of mechanical, chemical and electronic factors. Here chemical and strain profiles near the interface of LaAlO3/SrTiO3 heterostructures are correlated. Conductive and insulating samples have been processed, with thicknesses respectively above and below the commonly admitted conductivity threshold. The intermixing and structural distortions within the crystal lattice have been quantitatively measured near the interface with a depth resolution of unit cell size. A strong link between intermixing and structural distortions at such interfaces is highlighted: intermixing was more pronounced in the hetero-couple with conductive interface, whereas in-plane compressive strains extended deeper within the substrate of the hetero-couple with the insulating interface. This allows a better understanding of the interface local mechanisms leading to the conductivity. PMID:27301609

  2. Atomic-resolved depth profile of strain and cation intermixing around LaAlO3/SrTiO3 interfaces

    NASA Astrophysics Data System (ADS)

    Zaid, H.; Berger, M. H.; Jalabert, D.; Walls, M.; Akrobetu, R.; Fongkaew, I.; Lambrecht, W. R. L.; Goble, N. J.; Gao, X. P. A.; Berger, P.; Sehirlioglu, A.

    2016-06-01

    Novel behavior has been observed at the interface of LaAlO3/SrTiO3 heterostructures such as two dimensional metallic conductivity, magnetic scattering and superconductivity. However, both the origins and quantification of such behavior have been complicated due to an interplay of mechanical, chemical and electronic factors. Here chemical and strain profiles near the interface of LaAlO3/SrTiO3 heterostructures are correlated. Conductive and insulating samples have been processed, with thicknesses respectively above and below the commonly admitted conductivity threshold. The intermixing and structural distortions within the crystal lattice have been quantitatively measured near the interface with a depth resolution of unit cell size. A strong link between intermixing and structural distortions at such interfaces is highlighted: intermixing was more pronounced in the hetero-couple with conductive interface, whereas in-plane compressive strains extended deeper within the substrate of the hetero-couple with the insulating interface. This allows a better understanding of the interface local mechanisms leading to the conductivity.

  3. Further studies on the use of enzyme profiles to monitor residue accumulation in wildlife: Plasma enzymes in starlings fed graded concentrations of morsodren, DDE, Aroclor 1254, and malathion

    USGS Publications Warehouse

    Dieter, M.P.

    1975-01-01

    Wild-trapped starlings (Sturnus vulgaris) were fed concentrations of Morsodren (2, 4, and 8 ppm), DDE or Aroclor 1254 (5, 25, and 100 ppm), or malathion (8, 35, and 160 ppm) that were found to be sublethal in pen-reared Coturnix quail fed these amounts for 12 weeks. Plasma enzymes had to be measured earlier than planned in starlings fed Morsodren (at three weeks) or the organochlorine compounds (at seven weeks) because of unexpected, subsequent mortality. Variations in enzyme response were greater in wild than in pen-reared birds, but not enough to mask the toxicant-induced changes in enzyme activity. Cholinesterase activities decreased in birds fed Morsodren or malathion, and increased in those fed the organochlorine compounds. Lactate dehydrogenase activities increased two-fold in starlings fed Morsodren and two- to four-fold in those fed the organochlorine compounds, but only 50% in those fed malathion. Further examination of enzyme profiles showed that creatine kinase and aspartate aminotransferase activities increased two-to four-fold in birds fed Morsodren or the organochlorine compounds but not at all in those fed malathion. Thus the classes of environmental contaminants fed to starlings could be easily distinguished by these enzymatic parameters. Evaluation of enzymatic profiles appears to be a potentially valuable technique to monitor the presence of toxicants in wild populations, especially if used to complement standard chemical residue analyses. Here the residue analyses showed, after three weeks feeding, that mercury in the carcasses reflected the concentrations fed daily, whereas accumulation in the livers was two- to four-fold greater. After seven weeks feeding, liver residues of either organochlorine compound were about three-fold higher than the concentrations fed daily. However, four times as much DDE as Aroclor 1254 had accumulated in the carcasses.

  4. Milk yield, gross composition and fatty acid profile of dual-purpose Aosta Red Pied cows fed separate concentrate-forage versus total mixed ration.

    PubMed

    Renna, Manuela; Cornale, Paolo; Lussiana, Carola; Battaglini, Luca Maria; Turille, Germano; Mimosi, Antonio

    2014-01-01

    This study was designed to evaluate the effects of two feeding methods on milk yield, composition and fatty acid (FA) profile obtained from dual-purpose cattle. Twenty-four Aosta Red Pied cows beyond peak of lactation were assigned to two groups and fed hay and concentrates in the proportions 0.69 and 0.31 on a dry matter basis for 10 weeks. Concentrates were offered separately from forages 6 times a day (separate ration, SR) or as a total mixed ration (TMR). The feeding method did not significantly influence dry matter intake (16.8 vs. 16.9 kg/head/day for SR- and TMR-fed cows, respectively), milk yield (17.4 vs. 17.5 kg/head/day), milk fat, protein and lactose contents (36.4 vs. 35.2, 33.5 vs. 32.8, and 47.3 vs. 47.4 g/kg) and yields (607.9 vs. 613.4, 567.4 vs. 572.7 and 805.5 vs. 829.7 g/head/day). The overall milk FA profile was very similar between groups. Milk concentrations of FA used as indirect markers of rumen function (C18:2 t10c12, odd- and branched-chain FA) and the extent of ruminal biohydrogenation were comparable (P > 0.05) between SR- and TMR-fed cows, suggesting that ruminal pH did not vary considerably as a consequence of the feeding strategy applied. PMID:23841857

  5. Si concentration dependence of structural inhomogeneities in Si-doped Al{sub x}Ga{sub 1−x}N/Al{sub y}Ga{sub 1−y}N multiple quantum well structures (x = 0.6) and its relationship with internal quantum efficiency

    SciTech Connect

    Kurai, Satoshi Anai, Koji; Yamada, Yoichi; Miyake, Hideto; Hiramatsu, Kazumasa

    2014-12-21

    We investigated the distribution of luminescence in Si-doped Al{sub x}Ga{sub 1−x}N/Al{sub y}Ga{sub 1−y}N multiple quantum well (MQW) structures (x = 0.6) with different Si concentrations by cathodoluminescence (CL) mapping combined with scanning electron microscopy. The effects of surface morphology, dark spot density, and full width at half-maximum of spot CL spectra on internal quantum efficiency (IQE) were determined. A flat surface morphology and uniform CL map were observed for Si-doped AlGaN MQWs, in contrast to undoped AlGaN MQW and Si-doped AlGaN with relatively low Al content. The dark spot density in the Si-doped AlGaN MQWs increased exponentially as the Si concentration increased and did not explain the Si concentration dependence of IQE. In contrast, there was a clear correlation between the dark spot density and IQE of the AlGaN MQWs at a constant Si concentration. The emission energy distribution arising from the inhomogeneity of the relative Al content and the well layer thickness was estimated by monochromatic CL measurements, although there was almost no difference in the distribution for different Si concentrations. Therefore, the previously reported dependence of the defect complexes on Si concentration is reflected in the IQE of Si-doped AlGaN MQWs. Defect complexes composed of cation vacancies and impurities rather than dislocations and interfacial quality are the major contributor to the IQE of the Si-doped AlGaN MQWs with different Si concentrations.

  6. Determination of sulfuric acid concentration for anti-cavitation characteristics of Al alloy by two step anodizing process to forming nano porous.

    PubMed

    Lee, Seung-Jun; Kim, Seong-Kweon; Jeong, Jae-Yong; Kim, Seong-Jong

    2014-12-01

    Al alloy is a highly active metal but forms a protective oxide film having high corrosion resistance in atmosphere environment. However, the oxide film is not suitable for practical use, since the thickness of the film is not uniform and it is severly altered with formation conditions. This study focused on developing an aluminum anodizing layer having hardness, corrosion resistance and abrasion resistance equivalent to a commercial grade protective layer. Aluminum anodizing layer was produced by two-step aluminum anodizing oxide (AAO) process with different sulfuric acid concentrations, and the cavitation characteristics of the anodized coating layer was investigated. In hardness measurement, the anodized coating layer produced with 15 vol.% of sulfuric acid condition had the highest value of hardness but exhibited poor cavitation resistance due to being more brittle than those with other conditions. The 10 vol.% of sulfuric acid condition was thus considered to be the optimum condition as it had the lowest weight loss and damage depth. PMID:25971100

  7. Effects of caustic sodium concentration and molecular ratio of Na2O to Al2O3 on agglomeration in the precipitation process

    NASA Astrophysics Data System (ADS)

    Liu, Zhanwei; Chen, Wenmi; Li, Wangxing

    2010-11-01

    The supersaturation of sodium aluminate solution (liquor) is a prerequisite for agglomeration and the key factors that determine supersaturation of liquor are caustic sodium concentration (Nk) and molecular ratio of Na2O to Al2O3 (αk). In this paper, the effects of Nk and αk on the agglomeration process of seeded precipitation were studied. The results show that the Nk plays an important role in the agglomeration process. The supersaturation of liquor decreases with the increasing of Nk and so not only does the precipitation ratio of liquor decrease but also the particle size of agglomerate decreases. The supersaturation of liquor decreases with the increasing of αk and so the precipitation rate and depth of liquor decrease and thus the agglomeration of fine particles is weakened.

  8. The effect of sulfate on aluminum concentrations in natural waters: some stability relations in the system Al2O3-SO3-H2O at 298 K

    USGS Publications Warehouse

    Nordstrom, D.K.

    1982-01-01

    While gibbsite and kaolinite solubilities usually regulate aluminum concentrations in natural waters, the presence of sulfate can dramatically alter these solubilities under acidic conditions, where other, less soluble minerals can control the aqueous geochemistry of aluminum. The likely candidates include alunogen, Al2(SO4)3 ?? 17H2O, alunite, KAl3(SO4)2(OH)6, jurbanite, Al(SO4)(OH) ?? 5H2O, and basaluminite, Al4(SO4)(OH)10 ?? 5H2O. An examination of literature values shows that the log Ksp = -85.4 for alunite and log Ksp = -117.7 for basaluminite. In this report the log Ksp = -7.0 is estimated for alunogen and log Ksp = -17.8 is estimated for jurbanite. The solubility and stability relations among these four minerals and gibbsite are plotted as a function of pH and sulfate activity at 298 K. Alunogen is stable only at pH values too low for any natural waters (<0) and probably only forms as efflorescences from capillary films. Jurbanite is stable from pH < 0 up to the range of 3-5 depending on sulfate activity. Alunite is stable at higher pH values than jurbanite, up to 4-7 depending on sulfate activity. Above these pH limits gibbsite is the most stable phase. Basaluminite, although kinetically favored to precipitate, is metastable for all values of pH and sulfate activity. These equilibrium calculations predict that both sulfate and aluminum can be immobilized in acid waters by the precipitation of aluminum hydroxysulfate minerals. Considerable evidence supports the conclusion that the formation of insoluble aluminum hydroxy-sulfate minerals may be the cause of sulfate retention in soils and sediments, as suggested by Adams and Rawajfih (1977), instead of adsorption. ?? 1982.

  9. Concentration Profiling in Rat Tissue by High-Resolution Magic-Angle Spinning NMR Spectroscopy: Investigation of a Model Drug

    PubMed Central

    Lucas, Laura H.; Wilson, Sarah F.; Lunte, Craig E.; Larive, Cynthia K.

    2008-01-01

    The utility of high-resolution magic-angle spinning (HR-MAS) NMR for studying drug delivery in whole tissues was explored by dosing female Sprague–Dawley rats with topical or injectable benzoic acid (BA). In principle, HR-MAS NMR permits the detection of both intra- and extracellular compounds. This is an advantage over the previous detection of topically applied BA using microdialysis coupled to HPLC/UV as microdialysis samples only the extracellular space. Skin and muscle samples were analyzed by 1H HR-MAS NMR, and BA levels were determined using an external standard solution added to the sample rotor. One to two percent of the BA topical dose was detected in the muscle, showing that BA penetrated through the dermal and subcutaneous layers. Since BA was not detected in the muscle in the microdialysis studies, the NMR spectra revealed the intracellular localization of BA. The amount of BA detected in muscle after subcutaneous injection correlated with the distance from the dosing site. Overall, the results suggest that HR-MAS NMR can distinguish differences in the local concentration of BA varying with tissue type, dosage method, and tissue proximity to the dosing site. The results illustrate the potential of this technique for quantitative analysis of drug delivery and distribution and the challenges to be addressed as the method is refined. PMID:15859619

  10. Whole intact rapeseeds or sunflower oil in high-forage or high-concentrate diets affects milk yield, milk composition, and mammary gene expression profile in goats.

    PubMed

    Ollier, S; Leroux, C; de la Foye, A; Bernard, L; Rouel, J; Chilliard, Y

    2009-11-01

    This study aimed to ascertain the response of goat mammary metabolic pathways to concentrate and lipid feeding in relation to milk fatty acid (FA) composition and secretion. Sixteen midlactation multiparous goats received diets differing in forage-to-concentrate ratio [high forage (HF) 64:36, and low forage (LF) 43:57] supplemented or not with lipids [HF with 130 g/d of oil from whole intact rapeseeds (RS) and LF with 130 g/d of sunflower oil (SO)] in a 4 x 4 Latin square design. Milk yield, milk composition, FA profile, and FA secretion were measured, as well as the expression profiles of key genes in mammary metabolism and of 8,382 genes, using a bovine oligonucleotide microarray. After 3 wk of treatment, milk, lactose, and protein yields were lower with HF-RS than with the other diets, whereas treatment had no effect on milk protein content. Milk fat content was higher with the HF-RS and LF-SO diets than with the HF and LF diets, and SO supplementation increased milk fat yield compared with the LF diet. Decreasing the forage-to-concentrate ratio from 64:36 to 43:57 had a limited effect on goat milk FA concentrations and secretions. Supplementing the LF diet with SO changed almost all the FA concentrations, including decreases in medium-chain saturated FA and large increases in trans C18:1 and C18:2 isomers (particularly trans-11 C18:1 and cis-9, trans-11 conjugated linoleic acid), without significant changes in C18:0 and cis-9 C18:1, whereas supplementing the HF diet with RS led to a strong decrease in short- and medium-chain saturated FA and a very strong increase in C18:0 and cis-9 C18:1, without significant changes in trans C18:1 and conjugated linoleic acid. Despite the decreases in milk lactose and protein yields observed with HF-RS, and despite the decrease in milk medium-chain FA and the increase in C18 FA secretion with RS or SO supplementation, none of the dietary treatments had any effect on mammary mRNA expression of the key genes involved in lactose

  11. Effect of dietary sugar concentration and sunflower seed supplementation on lactation performance, ruminal fermentation, milk fatty acid profile, and blood metabolites of dairy cows.

    PubMed

    Razzaghi, A; Valizadeh, R; Naserian, A A; Mesgaran, M Danesh; Carpenter, A J; Ghaffari, M H

    2016-05-01

    Previous research has shown that both sunflower seed (SF) and sucrose (SC) supplementation can result in variation in milk fat concentration and composition, possibly due to altered fermentation patterns and biohydrogenation of fatty acids in the rumen. The objective of this study was to determine the effects of different sugar concentrations with or without SF supplementation on lactation performance, ruminal fermentation, and milk fatty acid profile in lactating dairy cows. Eight multiparous Holstein dairy cows (body weight=620±15kg, 60±10 d in milk, mean ± standard deviation) were randomly assigned to treatments in a replicated 4×4 Latin square design with a 2×2 factorial arrangement of treatments. Each 21-d period consisted of a 14-d diet adaptation period and 7-d collection period. Dairy cows were fed 1 of the following 4 diets: (1) no additional SC without SF supplementation (NSC-SF), (2) no additional SC with SF supplementation (NSC+SF), (3) SC without SF supplementation (SC-SF), and (4) SC with SF supplementation (SC+SF). The diets contained the same amount of forages (corn silage and alfalfa hay). Four isonitrogenous and isoenergetic diets were formulated by replacing corn grain with SC and SF and balanced using change in proportions of canola meal and sugar beet pulp. No interaction was detected between SC and SF supplementation with respect to dry matter intake, milk yield, and composition. A tendency was found for an interaction between inclusion of SC and SF on energy-corrected milk with the highest amount in the SC-SF diet. Ruminal pH and the molar proportion of acetate were affected by SC inclusion, with an increase related to the SC-SF diet. Diets containing SF decreased the concentrations of short-chain fatty acids (4:0 to 10:0) and medium-chain fatty acids (12:0 to 16:0) in milk fat. The addition of SC tended to decrease the concentration of total trans-18:1. These data provide evidence that exchanging SC for corn at 4% of dietary dry matter

  12. [Concentrations and Component Profiles PAHs in Surface Soils and Wheat Grains from the Cornfields Close to the Steel Smelting Industry in Handan, Hebei Province].

    PubMed

    Wu, Di; Wang, Yi-long; Liu, Wei-jian; Chen, Yuan-chen; Fu, Xiao-fang; Tao, Shu; Liu, Wen-xin

    2016-02-15

    In this study, paired surface soil and mature wheat grain samples were collected in the cornfields near the large Handan Steel Manufacturer; and the total concentrations and compositional profiles of the parent PAHs were measured, then the spatial distribution characteristics and correlation with total organic carbon fractions in soil were determined. Accordingly, a preliminary source identification was performed, and the association between PAHs in surface soil and wheat grain was briefly discussed. The median concentration of total PAHs in surface soils from the cornfields of Handan was 398.9 ng x g(-1) (ranged from 123.4 ng x g(-1) to 1626.4 ng x g(-1), where around 18% and 10% of all the studied soil samples were over the corresponding quality criteria for total PAHs and B [a] P in soils, respectively. The MMW and HMW species were the main components in the compositional profiles of surface soils. Based on the specific isomeric ratios of PAHs species, coal/biomass combustion and transportation fuel (tail gas) were the dominant mixed sources for the local PAHs emission. The fractions of surface soil TOC had significant positive correlations with the total PAHs and also with the individual components with different rings. In addition, the median concentration of total PAHs in wheat grains collected in the cornfields near the Handan Steel Manufacture was 27.0 ng x g(-1) (ranged from 19.0-34.0 ng x g(-1)). The levels in wheat grains were not high, and lower than the related hygienic standards of food proposed by EU and China. The LMW and MMW PAHs with 2 to 4 rings occupied a larger proportion, more than 84% of the total PAHs, which was largely different from the component profiles in surface soils. This situation suggested that the local sources of PAHs in wheat grains may originate not only from surface soil via root absorption and internal transportation, but also from ambient air through dry and wet deposition on the leaf surface (stoma). PMID:27363168

  13. Bio-active engineered 50 nm silica nanoparticles with bone anabolic activity: therapeutic index, effective concentration, and cytotoxicity profile in vitro

    PubMed Central

    Ha, Shin-Woo; Sikorski, James A.; Weitzmann, M. Neale; Beck, George R.

    2014-01-01

    Silica-based nanomaterials are generally considered to be excellent candidates for therapeutic applications particularly related to skeletal metabolism however the current data surrounding the safety of silica based nanomaterials is conflicting. This may be due to differences in size, shape, incorporation of composite materials, surface properties, as well as the presence of contaminants following synthesis. In this study we performed extensive in vitro safety profiling of ~50 nm spherical silica nanoparticles with OH-terminated or Polyethylene Glycol decorated surface, with and without a magnetic core, and synthesized by the Stöber method. Nineteen different cell lines representing all major organ types were used to investigate an in vitro lethal concentration (LC) and results revealed little toxicity in any cell type analyzed. To calculate an in vitro therapeutic index we quantified the effective concentration at 50% response (EC50) for nanoparticle-stimulated mineral deposition activity using primary bone marrow stromal cells (BMSCs). The EC50 for BMSCs was not substantially altered by surface or magnetic core. The calculated Inhibitory concentration 50% (IC50) for pre-osteoclasts was similar to the osteoblastic cells. These results demonstrate the pharmacological potential of certain silica-based nanomaterial formulations for use in treating bone diseases based on a favorable in vitro therapeutic index. PMID:24333519

  14. Growth of silicon-doped Al0.6Ga0.4N with low carbon concentration at high growth rate using high-flow-rate metal organic vapor phase epitaxy reactor

    NASA Astrophysics Data System (ADS)

    Ikenaga, Kazutada; Mishima, Akira; Yano, Yoshiki; Tabuchi, Toshiya; Matsumoto, Koh

    2016-05-01

    The relationship between the carbon concentration and electrical characteristics of silicon-doped AlGaN (Al > 0.5) was investigated using a high-flow-rate metal organic vapor phase epitaxy (MOVPE) reactor. The carbon concentration and electrical properties of AlGaN (Al > 0.5) were measured as a function of the growth rate, V/III ratio, and growth temperature. The growth rate of Al0.6Ga0.4N was linearly controlled up to 7.2 µm/h under a constant ammonia (NH3) flow rate. However, a decrease in V/III ratio resulted in an increase in carbon concentration to 8 × 1017 cm‑3. With increased growth temperature, the carbon concentration decreased to less than 2 × 1017 cm‑3 without showing any reduction in growth rate. As a result, n-type Al0.6Ga0.4N with a carrier concentration of 5.4 × 1018 cm‑3 and a resistivity of 2.2 × 10‑2 Ω·cm was obtained.

  15. Estimation of air concentrations and profiles for polychlorinated dibenzo-p-dioxins and dibenzofurans from calculated vegetation-air partition coefficients

    SciTech Connect

    Kjeller, L.O.; Rappe, C.; Jones, K.C.

    1995-12-31

    Air concentrations of vapor and particulate phase polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are predicted by use of calculated plant-air partition coefficients. The plant-air interaction is reduced to an octanol-air distribution at equilibrium. Partition coefficients are deduced from the fugacity approach and calculated from congener group average data of solubility, vapor pressure and octanol-water partition coefficient. Calculated partition coefficients were used for prediction of the PCDD/F levels and congener profile in air from archived herbage collected pre- and post-1940. Before 1940 the air had a fly ash or combustion derived PCDD/F composition. After 1940 Hp and OCDD/F are superimposed on the combustion pattern, reflection of their release from the extensive use of polychlorinated compounds, notably penta chlorophenol, but also related compounds.

  16. An overview on the use of backscattered sound for measuring suspended particle size and concentration profiles in non-cohesive inorganic sediment transport studies

    NASA Astrophysics Data System (ADS)

    Thorne, Peter D.; Hurther, David

    2014-02-01

    For over two decades, coastal marine scientists studying boundary layer sediment transport processes have been using, and developing, the application of sound for high temporal-spatial resolution measurements of suspended particle size and concentration profiles. To extract the suspended sediment parameters from the acoustic data requires an understanding of the interaction of sound with a suspension of sediments and an inversion methodology. This understanding is distributed around journals in a number of scientific fields and there is no single article that succinctly draws together the different components. In the present work the aim is to provide an overview on the acoustic approach to measuring suspended sediment parameters and assess its application in the study of non-cohesive inorganic suspended sediment transport processes.

  17. Calculating soil gas fluxes from gas concentration profiles: can we use standard DS models or should we use site-specific DS models?

    NASA Astrophysics Data System (ADS)

    Paulus, Sinikka; Jochheim, Hubert; Wirth, Stephan; Maier, Martin

    2015-04-01

    The apparent gas diffusion coefficient in soil (DS) is an important parameter describing soil aeration. It also links the profiles of soil gas concentration and soil gas flux using Fick's law. Soil gas diffusivity depends mainly on the structure of the pore system and the soil moisture status. There are several standard DS-models available that can easily be used for calculating DS. Another, more laborious option is to calibrate site specific DS models on soil core samples from the respective profile. We tested 4 standard DS models and a site-specific model and compared the resulting soil gas fluxes in two forest soils. Differences between the models were substantial. Another very important effect, however, is that standard DS models are usually derived from a single soil moisture measurement (device), that can result in an substantial offset in soil moisture estimation. The mean soil moisture content at a depth can be addressed more accurately by taking several soil cores. As a consequence, using standard DS models in combination with a single soil moisture measurement is less reliable than using site-specific models based on several soil samples.

  18. Use of high-resolution measurements for the retrieval of temperature and gas-concentration profiles from outgoing infrared spectra in the presence of cirrus clouds.

    PubMed

    Huang, Xianglei L; Yung, Yuk L; Margolis, Jack S

    2003-04-20

    We explore ways in which high-spectral-resolution measurements can aid in the retrieval of atmospheric temperature and gas-concentration profiles from outgoing infrared spectra when optically thin cirrus clouds are present. Simulated outgoing spectra that contain cirrus are fitted with spectra that do not contain cirrus, and the residuals are examined. For those lines with weighting functions that peak near the same altitude as the thin cirrus, unique features are observed in the residuals. These unique features are highly sensitive to the resolution of the instrumental line shape. For thin cirrus these residual features are narrow (< or = 0.1 cm(-1)), so high spectral resolution is required for unambiguous observation. The magnitudes of these unique features are larger than the noise of modern instruments. The sensitivities of these features to cloud height and cloud optical depth are also discussed. Our sensitivity studies show that, when the errors in the estimation of temperature profiles are not large, the dominant contribution to the residuals is the misinterpretation of cirrus. An analysis that focuses on information content is also presented. An understanding of the magnitude of the effect and of its dependence on spectral resolution as well as on spectral region is important for retrieving spacecraft data and for the design of future infrared instruments for forecasting weather and monitoring greenhouse gases. PMID:12716157

  19. Theoretical Treatment and Numerical Simulation of Potential and Concentration Profiles in Extremely Thin Non-Electroneutral Membranes Used for Ion-Selective Electrodes

    PubMed Central

    Morf, W. E.; Pretsch, E.; De Rooij, N. F.

    2010-01-01

    The applicability of extremely thin non-electroneutral membranes for ion-selective electrodes (ISEs) is investigated. A theoretical treatment of potential and concentration profiles in space-charge membranes of << 1 μm thickness is presented. The theory is based on the Nernst-Planck equation for ion fluxes, which reduces to Boltzmann’s formula at equilibrium, and on the Poisson relationship between space-charge density and electric field gradient. A general solution in integral form is obtained for the potential function and the corresponding ion profiles at equilibrium. A series of explicit sub-solutions is derived for particular cases. Membrane systems with up to three different ion species are discussed, including trapped ionic sites and co-extracted ions. Solid-contacted thin membranes (without formation of aqueous films at the inner interface) are shown to exhibit a sub-Nernstian response. The theoretical results are confirmed by numerical simulations using a simplified finite-difference procedure based on the Nernst-Planck-Poisson model, which are shown to be in excellent agreement. PMID:23255874

  20. Concentrations, profiles, and estimated human exposures for polychlorinated dibenzo-p-dioxins and dibenzofurans from electronic waste recycling facilities and a chemical industrial complex in Eastern China

    SciTech Connect

    Ma, J.; Kannan, K.; Cheng, J.; Horii, Y.; Wu, Q.; Wang, W.

    2008-11-15

    Electronic shredder waste and dust from e-waste facilities, and leaves and surface soil collected in the vicinity of a large scale e-waste recycling facility in Taizhou, Eastern China, were analyzed for total dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) including 2,3,7,8-substituted congeners. We also determined PCDD/Fs in surface agricultural soils from several provinces in China for comparison with soils from e-waste facilities. Concentrations of total PCDD/Fs were high in all of the matrices analyzed and ranged from 30.9 to 11,400 pg/g for shredder waste, 3460 to 9820 pg/g dry weight for leaves, 2560 to 148,000 pg/g dry weight for workshop-floor dust, and 854 to 10200 pg/g dry weight for soils. We also analyzed surface soils from a chemical industrial complex (a coke-oven plant, a coal-fired power plant, and a chlor-alkali plant) in Shanghai. Concentrations of total PCDD/Fs in surface soil from the chemical industrial complex were lower than the concentrations found in soils from e-waste recycling plants, but higher than the concentrations found in agricultural soils. Agricultural soils from six cities in China contained low levels of total PCDD/Fs. Profiles of dioxin toxic equivalents (TEQs) of 2,3,7,8-PCDD/Fs in soils from e-waste facilities in Taizhou differed from the profiles found in agricultural soils. The estimated daily intakes of TEQs of PCDD/Fs via soil/dust ingestion and dermal exposure were 2 orders of magnitude higher in people at e-waste recycling facilities than in people at the chemical industrial site, implying greater health risk for humans from dioxin exposures at e-waste recycling facilities. The calculated TEQ exposures for e-waste workers from dust and soil ingestion alone were 2-3 orders of magnitude greater than the exposures from soils in reference locations. 37 refs., 1 fig., 2 tabs.

  1. Influence of air-staging on the concentration profiles of NH{sub 3} and HCN in the combustion chamber of a CFB boiler burning coal

    SciTech Connect

    Kassman, H.; Karlsson, M.; Aamand, L.E.

    1999-07-01

    The characterization of the concentration profiles of NH{sub 3} and HCN are of great importance for increasing the knowledge of the formation and destruction pathways of NO and N{sub 2}O in a fluidized bed boiler. Further improvements of the sampling methods for the determination of both NH{sub 3} and HCN in the combustion chamber in full-scale CFB boilers are also needed. A gas-sampling probe connected to a Fourier Transform Infrared (FTIR) instrument and a gas-quenching (GQ) probe in which the sample is quenched directly in the probe tip by a circulating trapper solution were used. The FTIR technique is based on analysis of hot combustion gases, whereas the trapper solutions from the GQ probe were analyzed by means of wet chemistry. The tests were performed during coal combustion in a 12 MW CFB boiler, which was operated at three air-staging cases with the addition of limestone for sulfur capture. The concentration profiles of NH{sub 3} and HCN in the combustion chamber showed a different pattern concerning the influence of air-staging. The highest levels of NH{sub 3} were observed during reducing condition (severe air-staging), and the lowest were found under oxidizing conditions (no air-staging). The levels of HCN were much lower than those measured for NH{sub 3}. The highest levels of HCN were observed for reversed air-staging and severe air-staging showed almost no HCN. The potential reactors involving NH{sub 3} and HCN in the combustion chamber as well as the potential measurement errors in each sampling technique are discussed for the three air-staging cases.

  2. Concentration and relaxation depth profiles of InxGa1-xAs/GaAs and GaAs1-xPx/GaAs graded epitaxial films studied by x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Benediktovitch, A.; Ulyanenkov, A.; Rinaldi, F.; Saito, K.; Kaganer, V. M.

    2011-07-01

    A method is proposed to determine the concentration and relaxation depth profiles in graded epitaxial films from x-ray reciprocal space maps (RSMs). Various approximations in the kinematical x-ray diffraction from epitaxial films with the misfit dislocation density depth profile are developed. We show that a symmetric and an asymmetric RSM, or two asymmetric RSMs, contain enough information to obtain the concentration, relaxation, and lattice tilt depth profiles without any additional assumptions. The proposed approach is applied to InxGa1-xAs/GaAs and GaAs1-xPx/GaAs epitaxial graded films. The reconstructed concentration and dislocation density depth profiles are found to be in an agreement with the ones expected from the growth conditions.

  3. Influence of sodium dodecyl sulfate concentration on the photocatalytic activity and dielectric properties of intercalated sodium dodecyl sulfate into Zn–Cd–Al layered double hydroxide

    SciTech Connect

    Ahmed, Abdullah Ahmed Ali; Talib, Zainal Abidin; Hussein, Mohd Zobir

    2015-02-15

    Highlights: • Zn–Cd–Al–LDH–DS were synthesized with different SDS concentrations. • Photocatalytic activity of samples was improved by increasing SDS concentration. • Dielectric response of LDH can be described by anomalous low frequency dispersion. • The dc conductivity values were calculated for Zn–Cd–Al–LDH–DS samples. • ESR spectra exhibited the successful intercalation of DS molecule into LDH gallery. - Abstract: Sodium dodecyl sulfate (SDS) has been successfully intercalated into Zn–Cd–Al–LDH precursor with different SDS concentrations (0.2, 0.3, 0.4, 0.5 and 1 mol L{sup −1}) using the coprecipitation method at (Zn{sup 2+} + Cd{sup 2+})/Al{sup 3+} molar ratio of 13 and pH 8. The structural, morphological, texture and composition properties of the synthesized (Zn–Cd–Al–LDH–DS) nanostructure were investigated using powder X-ray diffraction (PXRD), scanning electron microscope (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR), respectively. The photocatalytic activity of these materials was developed by increasing the concentration of intercalated SDS. The absorbance spectra have been used to detect an anion in the LDH interlayer before and after the intercalation process, which confirmed the presence of the dodecyl sulfate (DS{sup −}) anion into LDH gallery after intercalation. The anomalous low frequency dispersion (ALFD) has been used to describe the dielectric response of Zn–Cd–Al–LDH–DS nanostructure using the second type of universal power law. At low frequency, the polarization effect of electrodes caused the rising in dielectric constant and loss values. An important result of the dielectric measurements is the calculated dc conductivity values, which are new in dielectric spectroscopy of LDH materials. An important result of the electron spin resonance (ESR) spectra exhibited the successful intercalation of DS molecule into LDH gallery. The g-factor value was affected by

  4. Sediment concentration profiles in bed-near-bed layers under unsteady flow and sediment conditions : a CT-Scanned flume investigation

    NASA Astrophysics Data System (ADS)

    Leclair, Suzanne; Long, Bernard

    2015-04-01

    This paper presents a case study from a CT-scan flume experiment on the variation in sediment transport (concentration) under transitional, initially high-regime (but decreasing), sub-critical flow with bed erosion or no net aggradation. The objective is to better understand sediment transport during unsteady flows such as during a wining flood. In particular, the effect of mud-aggregate transport on sediment concentration in the bed-near-bed continuum was addressed. CT-scans were taken during sediment transport, with plane beds or dunes being the bed state. The density material (water and/or sediment) in over 105 volumes (voxels, each approximately equivalent to a grain of 0.8 mm) were analysed. Computed Tomography technology provides high-resolution results, both in time and space, and allows recognition of subtle changes in the shape of relative sediment concentration profile with bed states. The migration and attrition of mud aggregates in this experiment increased the mean volume fraction sediment concentration in the bed-near-bed layer (lower 5% of the flow) by a factor of about 2, from an inital value of 0.12 up to 0.25, and back to 0.13 when the supply ended. Also, the presence of mud-aggregates in the preserved deposits (transported as bedload) increases bed porosity. This case study demonstrates the great potential of Computed Tomography in process-oriented, experimental sedimentology. The community would benefit from more collaborative research using this technology, including data sharing as suggested by initiatives such as the Sediment Experimentalists Network (http://workspace.earthcube.org/sen)

  5. Body Composition, Lipid Profile, Adipokine Concentration, and Antioxidant Capacity Changes during Interventions to Treat Overweight with Exercise Programme and Whole-Body Cryostimulation

    PubMed Central

    Lubkowska, Anna; Dudzińska, Wioleta; Bryczkowska, Iwona; Dołęgowska, Barbara

    2015-01-01

    The aim of this study was to determine the effect of six-month-long physical exercise programme with a two-time exposure to whole-body cryostimulation (WBC) in 20 sessions on antioxidant enzyme activities, lipid profile, and body composition changes in obese people (30 adult subjects; BMI = 30.39 ± 4.31 kg/m2). Blood samples were taken before the programme, one month following the exercise programme, before and after the first WBC treatment, six months following the exercise programme, after the second WBC treatment, and finally one month after the intervention. Six months of moderate aerobic activity combined with WBC did not change body mass or fat and lean body mass percentages, or circulating adiponectin, leptin, and resistin concentrations. In response to intervention a significant decrease in the level of low-density lipoprotein and triglycerides was observed, with a slight increase in high-density lipoprotein concentration. The nature of changes in the activity of respective antioxidant enzymes was not identical. After one month of increased physical activity, a significant decrease in superoxide dismutase, catalase, and glutathione reductase activities was observed (13%, 8%, and 70%, resp.). The SOD activity increased significantly after successive whole-body cryostimulation sessions. As regards catalase, a significant progressive decrease in its activity was observed. PMID:26171117

  6. Disruption of OsSULTR3;3 reduces phytate and phosphorus concentrations and alters the metabolite profile in rice grains.

    PubMed

    Zhao, Haijun; Frank, Thomas; Tan, Yuanyuan; Zhou, Chenguang; Jabnoune, Mehdi; Arpat, A Bulak; Cui, Hairui; Huang, Jianzhong; He, Zuhua; Poirier, Yves; Engel, Karl-Heinz; Shu, Qingyao

    2016-08-01

    Two low phytic acid (lpa) mutants have been developed previously with the aim to improve the nutritional value of rice (Oryza sativa) grains. In the present study, the impacts of lpa mutations on grain composition and underlying molecular mechanisms were investigated. Comparative compositional analyses and metabolite profiling demonstrated that concentrations of both phytic acid (PA) and total phosphorus (P) were significantly reduced in lpa brown rice, accompanied by changes in other metabolites and increased concentrations of nutritionally relevant compounds. The lpa mutations modified the expression of a number of genes involved in PA metabolism, as well as in sulfate and phosphate homeostasis and metabolism. Map-based cloning and complementation identified the underlying lpa gene to be OsSULTR3;3. The promoter of OsSULTR3;3 is highly active in the vascular bundles of leaves, stems and seeds, and its protein is localized in the endoplasmic reticulum. No activity of OsSULTR3;3 was revealed for the transport of phosphate, sulfate, inositol or inositol 1,4,5 triphosphate by heterologous expression in either yeast or Xenopus oocytes. The findings reveal that OsSULTR3;3 plays an important role in grain metabolism, pointing to a new route to generate value-added grains in rice and other cereal crops. PMID:27110682

  7. The Effects of Cd2+ Concentration on the Structure, Optical and Luminescence Properties of MgAl2O4:x% Cd2+ (0 < x ≤ 1.75) Nanophosphor Prepared by Sol-Gel Method

    NASA Astrophysics Data System (ADS)

    Motloung, S. V.; Dejene, F. B.; Sithole, M. E.; Koao, L. F.; Ntwaeaborwa, O. M.; Swart, H. C.; Motaung, T. E.

    2016-06-01

    Cadmium-doped magnesium aluminate (MgAl2O4:x% Cd2+) powders with different cadmium concentrations (0 < x ≤ 1.75) were prepared by the sol-gel method. Energy dispersive x-ray spectroscopy (EDS) analysis confirmed the presence of the expected elements (Mg, Al, O, and Cd). The x-ray diffraction (XRD) analysis revealed that the powders crystallized into the cubic spinel structure. Cd2+ doping influenced crystallinity of the powder samples. The crystallite size and particle morphology were not affected by variation in the Cd2+ concentration. Ultraviolet-visible spectroscopy (UV-vis) measurements revealed that the band gap of the MgAl2O4 was influenced by Cd2+ doping. Un-doped and Cd2+-doped MgAl2O4 nanophosphors exhibited violet emission at 392 nm. There was no evidence of the emission peak shift, which suggested that all emissions originated from the defects within the host material. Increasing the Cd2+ concentration up-to 0.88 mol.% lead to luminescence intensity enhancement, while further increase of Cd2+ concentration lead to concentration quenching. The critical energy transfer distance (R c) between the neighbouring donors and acceptors was found to be 5.21 Å, suggesting that the multipole-multipole interaction (M-MI) is the major cause of concentration quenching. Commission Internationale de l'Elcairage (CIE) colour coordinates confirmed non-tuneable violet emission with intensity dependent on the Cd2+ concentration.

  8. Diffusion Research in BCC Ti-Al-Mo Ternary Alloys

    NASA Astrophysics Data System (ADS)

    Chen, Yi; Tang, Bin; Xu, Guanglong; Wang, Chuanyun; Kou, Hongchao; Li, Jinshan; Cui, Yuwen

    2014-04-01

    Interdiffusion in Ti-Al-Mo β solid solution was investigated at 1523 K (1250 °C) by analyzing diffusion couples. From the concentration profiles analytically represented by error function expansion (ERFEX), the ternary interdiffusion coefficients and impurity diffusivity were extracted by the Whittle-Green and generalized Hall methods. A comparison of the diffusion in five Ti-Al-X (Co, Cr, Fe, Mo, and V) ternaries reveals Ti-Al-Mo is comparably like Ti-Al-(Cr, V) while Ti-Al-(Co, Fe) are predominantly of interstitial nature.

  9. Circulatory endotoxin concentration and cytokine profile in response to exertional-heat stress during a multi-stage ultra-marathon competition.

    PubMed

    Gill, Samantha K; Teixeira, Ana; Rama, Luis; Prestes, Jonato; Rosado, Fatima; Hankey, Joanne; Scheer, Volker; Hemmings, Krystal; Ansley-Robson, Paula; Costa, Ricardo J S

    2015-01-01

    Exertional-heat stress has the potential to disturb intestinal integrity, leading to enhanced permeability of enteric pathogenic micro-organisms and associated clinical manifestations. The study aimed to determine the circulatory endotoxin concentration and cytokine profile of ultra-endurance runners (UER, n=19) and a control group (CON, n=12) during a five stage 230km ultra-marathon (mean ± SD: 27h38min ± 3h55min) conducted in hot and dry environmental conditions (30ºC to 40ºC and 31% to 40% relative humidity). Body mass and tympanic temperature were measured, and venous blood samples were taken before (pre-stage) and immediately after (post-stage) each stage of the ultra-marathon for the analysis of gram-negative bacterial endotoxin, C-reactive protein, cytokine profile (IL-6, IL-1β, TNF-α, IFN-γ, IL-10, and IL- 1ra), and plasma osmolality. Gastrointestinal symptoms and perceptive thermal tolerance rating were also monitored throughout competition. Mean exercise-induced body mass loss over the five stages ranged 1.0% to 2.5%. Pre- and poststage plasma osmolality in UER ranged277 to 282mOsmol/kg and 286 to 297 mOsmol/kg, respectively. Pre-stage concentrations of endotoxin (peak: 21% at Stage 5), C-reactive protein (889% at Stage 3), IL-6 (152% at Stage 2), IL-1β (95% at Stage 5), TNF-α (168% at Stage 5), IFN-γ (102% at Stage 5),IL-10 (1271% at Stage 3), and IL-1ra (106% at Stage 5) increased as the ultra-marathon progressed in UER; while no changes in CON were observed (except for IL-1β, 71% at Stage 5). Pre- to post-stage increases were observed for endotoxin (peak: 22% at Stage 3), C-reactive protein (25% at Stage 1), IL-6 (238% at Stage 1), IL-1β (64% at Stage 1), TNF-α (101% at Stage 1), IFN-γ (39% at Stage 1), IL-10 (1100% at Stage 1), and IL-1ra(207% at Stage 1) concentrations in UER. Multi-stage ultra-marathon competition in the heat resulted in a modest circulatory endotoxaemia accompanied by a pronounced pro-inflammatory cytokinaemia by post

  10. Concentration-time profiles of gamma-hydroxybutyrate in blood after recreational doses are best described by zero-order rather than first-order kinetics.

    PubMed

    Jones, A W; Eklund, A; Kronstrand, R

    2009-01-01

    The recreational drug gamma-hydroxybutyrate (GHB) has a short plasma elimination half-life (t(1/2)) reported to be about 30-50 min. However, this represents a terminal half-life and therefore might not necessarily apply after large (abuse) doses are taken. Clinical studies with sodium oxybate (sodium salt of GHB) suggest that zero-order rather than first-order kinetics are more appropriate to describe post-peak concentration-time (C-T) profiles. We report the case of a 23-year-old male found unconscious by the police and a blood sample contained 100 mg/L GHB and 0.14 g% ethanol. On regaining consciousness the man admitted drinking alcohol about 6 h earlier but claimed that his drink must have been spiked with GHB. The police wanted to know how much GHB had been administered to account for the man's clinical condition. A back-calculation for 6 h, assuming a GHB half-life of 40 min, gives a very high concentration in blood of approximately 900 mg/L, which would probably have proven fatal. Back-calculating using zero-order kinetics and a proposed elimination rate of 18 mg/L per hour leads to a GHB concentration of 208 mg/L, which is much more realistic. Toxicologists should not arbitrarily apply the principles of first-order kinetics after abuse doses of drugs, when zero-order or saturation kinetics (Michaelis-Menten) are more appropriate. PMID:19653937

  11. Enhancement of two dimensional electron gas concentrations due to Si{sub 3}N{sub 4} passivation on Al{sub 0.3}Ga{sub 0.7}N/GaN heterostructure: strain and interface capacitance analysis

    SciTech Connect

    Dinara, Syed Mukulika Jana, Sanjay Kr.; Ghosh, Saptarsi; Mukhopadhyay, Partha; Kumar, Rahul; Chakraborty, Apurba; Biswas, Dhrubes; Bhattacharya, Sekhar

    2015-04-15

    Enhancement of two dimensional electron gas (2DEG) concentrations at Al{sub 0.3}Ga{sub 0.7}N/GaN hetero interface after a-Si{sub 3}N{sub 4} (SiN) passivation has been investigated from non-destructive High Resolution X-ray Diffraction (HRXRD) analysis, depletion depth and capacitance-voltage (C-V) profile measurement. The crystalline quality and strained in-plane lattice parameters of Al{sub 0.3}Ga{sub 0.7}N and GaN were evaluated from double axis (002) symmetric (ω-2θ) diffraction scan and double axis (105) asymmetric reciprocal space mapping (DA RSM) which revealed that the tensile strain of the Al{sub 0.3}Ga{sub 0.7}N layer increased by 15.6% after SiN passivation. In accordance with the predictions from theoretical solution of Schrödinger-Poisson’s equations, both electrochemical capacitance voltage (ECV) depletion depth profile and C-V characteristics analyses were performed which implied effective 9.5% increase in 2DEG carrier density after passivation. The enhancement of polarization charges results from increased tensile strain in the Al{sub 0.3}Ga{sub 0.7}N layer and also due to the decreased surface states at the interface of SiN/Al{sub 0.3}Ga{sub 0.7}N layer, effectively improving the carrier confinement at the interface.

  12. Concentration profiles, source apportionment and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in dumpsite soils from Agbogbloshie e-waste dismantling site, Accra, Ghana.

    PubMed

    Daso, Adegbenro P; Akortia, Eric; Okonkwo, Jonathan O

    2016-06-01

    The concentrations of eighteen (18) polycyclic aromatic hydrocarbons (PAHs), including the 16 USEPA's priority PAHs as well as two alkyl-substituted naphthalenes were determined in dumpsite soils collected from different sampling sites within the Agbogbloshie e-waste dismantling site in Accra, Ghana. Following their isolation with ultrasonic-assisted extraction technique, the concentrations of the PAHs were determined by gas chromatography mass spectrometry (GC-MS). Loss-on-ignition (LOI) method was employed for the determination of total organic carbon (TOC) of the soil samples. The mean Σ18PAHs obtained were 3006, 5627, 3046, 5555, and 7199 ng g(-1) dry weight (dw) for sampling sites A (mosque), B (dismantling site), C (residential house/police station), D (personal computer repairers' shop) and E (e-waste open burning area), respectively. In all cases, the prevalence of phenanthrene, fluoranthene and pyrene was generally observed across the sampling sites. In this study, PAHs with two to three rings and four to six rings exhibited strong positive correlations, whereas BbF and BkF showed weak positive and negative correlations with other PAHs investigated. With the exception of BbF and BkF, all the PAHs had moderate to strong positive correlations with the TOC. Benzo[a]pyrene equivalent (BaPeq) concentration is a useful indicator of the carcinogenic potency of environmental matrices and these ranged between 111 and 454 ng g(-1), which are generally below the 'safe' level of 600 ng g(-1) established for the protection of the environment and human health. Interestingly, the seven carcinogenic PAHs were the major contributors to the BaPeq concentrations accounting between 97.7 and 98.3 %. Despite the minimal risk to cancer via exposure to the investigated dumpsite soil as indicated in the present study, the prolonged exposure to these pollutants via various exposure pathways may result in increased risk to cancer over time. The application of several

  13. The effect of the concentration of citric acid and pH values on the preparation of MgAl{sub 2}O{sub 4} ultrafine powder by citrate sol-gel process

    SciTech Connect

    Zhang Haijun; Jia Xiaolin; Yan Yongjie; Liu Zhanjie; Yang Daoyuan; Li Zhenzhen

    2004-05-05

    Ultrafine MgAl{sub 2}O{sub 4} was synthesized by citrate sol-gel process. A model was presented to evaluate the concentration of species in a citric solution for preparing MgAl{sub 2}O{sub 4} ultrafine powder. The evaluated concentration of species can provide valuable information and help in selecting the optimal condition for preparation of MgAl{sub 2}O{sub 4} powder by citrate sol-gel process. The influence of molar ratio of cations, citric acid and pH on the formation of MgAl{sub 2}O{sub 4} was studied. The spinel precursor gel and the ultrafine MgAl{sub 2}O{sub 4} spinel were characterized by X-ray diffraction (XRD), differential thermal analysis, thermogravimetric (TG-DTA) and scanning electron microscope (SEM). The results show that the MgAl{sub 2}O{sub 4} spinel phase begins to form at 600 deg. C, and most of MgAl{sub 2}O{sub 4} crystals are spherical with a crystal size about 30-50 nm.

  14. Effect of L- or DL-methionine Supplementation on Nitrogen Retention, Serum Amino Acid Concentrations and Blood Metabolites Profile in Starter Pigs.

    PubMed

    Tian, Q Y; Zeng, Z K; Zhang, Y X; Long, S F; Piao, X S

    2016-05-01

    The objective of the current study was to evaluate the effect of supplementation of either L-methionine (L-Met) or DL-methionine (DL-Met) to diets of starter pigs on nitrogen (N) balance, metabolism, and serum amino acid profile. Eighteen crossbred (Duroc×Landrace×Yorkshire) barrows weighing 15.45±0.88 kg were randomly allotted to 1 of 3 diets with 6 pigs per treatment. The diets included a basal diet (Met-deficient diet) containing 0.24% standardized ileal digestibility Met with all other essential nutrients meeting the pig's requirements. The other two diets were produced by supplementing the basal diet with 0.12% DL-Met or L-Met. The experiment lasted for 18 days, consisting of a 13-day adaptation period to the diets followed by a 5-day experimental period. Pigs were fed ad libitum and free access to water throughout the experiment. Results showed that the supplementation of either L-Met or DL-Met improved N retention, and serum methionine concentration, and decreased N excretion compared with basal diet (p<0.01). The N retention of pigs fed diets supplemented with the same inclusion levels of DL-Met or L-Met were not different (p>0.05). In conclusion, on equimolar basis DL-Met and L-Met are equally bioavailable as Met sources for starter pigs. PMID:26954214

  15. Effects of adding a concentrated pomegranate-residue extract to the ration of lactating cows on in vivo digestibility and profile of rumen bacterial population.

    PubMed

    Jami, E; Shabtay, A; Nikbachat, M; Yosef, E; Miron, J; Mizrahi, I

    2012-10-01

    This study characterizes the effects of concentrated pomegranate-peel extract (CPE) addition to the TMR at levels of 1, 2, or 4% on voluntary intake, in vivo digestibility, milk yield and composition, and profile of rumen bacterial and archaeal populations in lactating Holstein cows. Supplementation of CPE significantly affected the abundance of methanogenic archaea and specific ruminal bacterial species related to cellulolytic activities and soluble sugar and lactic acid fermentation, as revealed by real-time PCR quantification. Furthermore, CPE supplementation had a significant dose-dependent effect on the whole ruminal bacterial community, as determined by automated ribosomal intergenic spacer analysis. These changes were accompanied by a significant increase in digestibility of dry matter, crude protein, and neutral detergent fiber, as well as milk and energy-corrected milk yields in cows fed the 4% CPE supplement. These results suggest that CPE supplementation significantly affects the rumen bacterial communities, which in turn may be related to a beneficial effect on dairy cow performance. PMID:22863105

  16. Expression Profiling-Based Identification of CO2-Responsive Genes Regulated by CCM1 Controlling a Carbon-Concentrating Mechanism in Chlamydomonas reinhardtii1

    PubMed Central

    Miura, Kenji; Yamano, Takashi; Yoshioka, Satoshi; Kohinata, Tsutomu; Inoue, Yoshihiro; Taniguchi, Fumiya; Asamizu, Erika; Nakamura, Yasukazu; Tabata, Satoshi; Yamato, Katsuyuki T.; Ohyama, Kanji; Fukuzawa, Hideya

    2004-01-01

    Photosynthetic acclimation to CO2-limiting stress is associated with control of genetic and physiological responses through a signal transduction pathway, followed by integrated monitoring of the environmental changes. Although several CO2-responsive genes have been previously isolated, genome-wide analysis has not been applied to the isolation of CO2-responsive genes that may function as part of a carbon-concentrating mechanism (CCM) in photosynthetic eukaryotes. By comparing expression profiles of cells grown under CO2-rich conditions with those of cells grown under CO2-limiting conditions using a cDNA membrane array containing 10,368 expressed sequence tags, 51 low-CO2 inducible genes and 32 genes repressed by low CO2 whose mRNA levels were changed more than 2.5-fold in Chlamydomonas reinhardtii Dangeard were detected. The fact that the induction of almost all low-CO2 inducible genes was impaired in the ccm1 mutant suggests that CCM1 is a master regulator of CCM through putative low-CO2 signal transduction pathways. Among low-CO2 inducible genes, two novel genes, LciA and LciB, were identified, which may be involved in inorganic carbon transport. Possible functions of low-CO2 inducible and/or CCM1-regulated genes are discussed in relation to the CCM. PMID:15235119

  17. Effect of L- or DL-methionine Supplementation on Nitrogen Retention, Serum Amino Acid Concentrations and Blood Metabolites Profile in Starter Pigs

    PubMed Central

    Tian, Q. Y.; Zeng, Z. K.; Zhang, Y. X.; Long, S. F.; Piao, X. S.

    2016-01-01

    The objective of the current study was to evaluate the effect of supplementation of either L-methionine (L-Met) or DL-methionine (DL-Met) to diets of starter pigs on nitrogen (N) balance, metabolism, and serum amino acid profile. Eighteen crossbred (Duroc×Landrace×Yorkshire) barrows weighing 15.45±0.88 kg were randomly allotted to 1 of 3 diets with 6 pigs per treatment. The diets included a basal diet (Met-deficient diet) containing 0.24% standardized ileal digestibility Met with all other essential nutrients meeting the pig’s requirements. The other two diets were produced by supplementing the basal diet with 0.12% DL-Met or L-Met. The experiment lasted for 18 days, consisting of a 13-day adaptation period to the diets followed by a 5-day experimental period. Pigs were fed ad libitum and free access to water throughout the experiment. Results showed that the supplementation of either L-Met or DL-Met improved N retention, and serum methionine concentration, and decreased N excretion compared with basal diet (p<0.01). The N retention of pigs fed diets supplemented with the same inclusion levels of DL-Met or L-Met were not different (p>0.05). In conclusion, on equimolar basis DL-Met and L-Met are equally bioavailable as Met sources for starter pigs. PMID:26954214

  18. Migration of cyclo-diBA from coatings into canned food: method of analysis, concentration determined in a survey and in silico hazard profiling.

    PubMed

    Biedermann, Sandra; Zurfluh, Michael; Grob, Koni; Vedani, Angelo; Brüschweiler, Beat J

    2013-08-01

    Cyclo-diBA, the cyclic product formed from bisphenol A and bisphenol A diglycidyl ether during production of epoxy resins, was measured in canned food using reversed phase HPLC with fluorescence detection. Half (9 of 17) of the samples of canned fish in oil collected in April 2010 contained cyclo-diBA with an average concentration of 1025 μg/kg and a maximum of 1980 μg/kg. In September 2012, cyclo-diBA was detectable (>25 μg/kg) in merely 13 from 44 such products; the average concentration in these was 807 μg/kg and the maximum now reached 2640 μg/kg. Fish in brine contained far less cyclo-diBA. The majority of the canned meat products contained cyclo-diBA at a mean concentration of 477 μg/kg and a maximum of 1050 μg/kg. All prepared meals, such as ravioli or soups, contained cyclo-diBA, with a mean at 287 μg/kg. In canned tomatoes, peas and other vegetables in water or fruits in syrup, no cyclo-diBA was detected (<25 μg/kg). Since no experimental toxicity data are available except for its cytotoxicity, an in silico hazard profiling was performed. Cyclo-diBA seems to be stable and of low reactivity. There is indication for considerable oral bioavailability and for the potential to accumulate in the human body. Cyclo-diBA can be metabolized into cyclic and acyclic compounds. Based on SAR assessment for cyclo-diBA and read-across from BADGE to linear cyclo-diBA metabolites, genotoxic effects are improbable. Specific binding of cyclo-diBA to nuclear receptors, such as ERβ, can be predicted, indicating a potential endocrine-disrupting potency. The limit by the EFSA guidelines of 50 μg/person/d for compounds shown not to be genotoxic as well as the TTC-based Cramer structural class III value of 90 μg/person/d could be exceeded several fold by high consumers of canned fish in oil with high brand loyalty. As a consequence, risk reduction measures were taken. PMID:23603005

  19. Milk Yield, Composition, and Fatty Acid Profile in Dairy Cows Fed a High-concentrate Diet Blended with Oil Mixtures Rich in Polyunsaturated Fatty Acids.

    PubMed

    Thanh, Lam Phuoc; Suksombat, Wisitiporn

    2015-06-01

    To evaluate the effects of feeding linseed oil or/and sunflower oil mixed with fish oil on milk yield, milk composition and fatty acid (FA) profiles of dairy cows fed a high-concentrate diet, 24 crossbred primiparous lactating dairy cows in early lactation were assigned to a completely randomized design experiment. All cows were fed a high-concentrate basal diet and 0.38 kg dry matter (DM) molasses per day. Treatments were composed of a basal diet without oil supplement (Control), or diets of (DM basis) 3% linseed and fish oils (1:1, w/w, LSO-FO), or 3% sunflower and fish oils (1:1, w/w, SFO-FO), or 3% mixture (1:1:1, w/w) of linseed, sunflower, and fish oils (MIX-O). The animals fed SFO-FO had a 13.12% decrease in total dry matter intake compared with the control diet (p<0.05). No significant change was detected for milk yield; however, the animals fed the diet supplemented with SFO-FO showed a depressed milk fat yield and concentration by 35.42% and 27.20%, respectively, compared to those fed the control diet (p<0.05). Milk c9, t11-conjugated linoleic acid (CLA) proportion increased by 198.11% in the LSO-FO group relative to the control group (p<0.01). Milk C18:3n-3 (ALA) proportion was enhanced by 227.27% supplementing with LSO-FO relative to the control group (p<0.01). The proportions of milk docosahexaenoic acid (DHA) were significantly increased (p<0.01) in the cows fed LSO-FO (0.38%) and MIX-O (0.23%) compared to the control group (0.01%). Dietary inclusion of LSO-FO mainly increased milk c9, t11-CLA, ALA, DHA, and n-3 polyunsaturated fatty acids (PUFA), whereas feeding MIX-O improved preformed FA and unsaturated fatty acids (UFA). While the lowest n-6/n-3 ratio was found in the LSO-FO, the decreased atherogenecity index (AI) and thrombogenicity index (TI) seemed to be more extent in the MIX-O. Therefore, to maximize milk c9, t11-CLA, ALA, DHA, and n-3 PUFA and to minimize milk n-6/n-3 ratio, AI and TI, an ideal supplement would appear to be either LSO-FO or

  20. Milk Yield, Composition, and Fatty Acid Profile in Dairy Cows Fed a High-concentrate Diet Blended with Oil Mixtures Rich in Polyunsaturated Fatty Acids

    PubMed Central

    Thanh, Lam Phuoc; Suksombat, Wisitiporn

    2015-01-01

    To evaluate the effects of feeding linseed oil or/and sunflower oil mixed with fish oil on milk yield, milk composition and fatty acid (FA) profiles of dairy cows fed a high-concentrate diet, 24 crossbred primiparous lactating dairy cows in early lactation were assigned to a completely randomized design experiment. All cows were fed a high-concentrate basal diet and 0.38 kg dry matter (DM) molasses per day. Treatments were composed of a basal diet without oil supplement (Control), or diets of (DM basis) 3% linseed and fish oils (1:1, w/w, LSO-FO), or 3% sunflower and fish oils (1:1, w/w, SFO-FO), or 3% mixture (1:1:1, w/w) of linseed, sunflower, and fish oils (MIX-O). The animals fed SFO-FO had a 13.12% decrease in total dry matter intake compared with the control diet (p<0.05). No significant change was detected for milk yield; however, the animals fed the diet supplemented with SFO-FO showed a depressed milk fat yield and concentration by 35.42% and 27.20%, respectively, compared to those fed the control diet (p<0.05). Milk c9, t11-conjugated linoleic acid (CLA) proportion increased by 198.11% in the LSO-FO group relative to the control group (p<0.01). Milk C18:3n-3 (ALA) proportion was enhanced by 227.27% supplementing with LSO-FO relative to the control group (p<0.01). The proportions of milk docosahexaenoic acid (DHA) were significantly increased (p<0.01) in the cows fed LSO-FO (0.38%) and MIX-O (0.23%) compared to the control group (0.01%). Dietary inclusion of LSO-FO mainly increased milk c9, t11-CLA, ALA, DHA, and n-3 polyunsaturated fatty acids (PUFA), whereas feeding MIX-O improved preformed FA and unsaturated fatty acids (UFA). While the lowest n-6/n-3 ratio was found in the LSO-FO, the decreased atherogenecity index (AI) and thrombogenicity index (TI) seemed to be more extent in the MIX-O. Therefore, to maximize milk c9, t11-CLA, ALA, DHA, and n-3 PUFA and to minimize milk n-6/n-3 ratio, AI and TI, an ideal supplement would appear to be either LSO-FO or

  1. Influence of c-axis orientation and scandium concentration on infrared active modes of magnetron sputtered Sc{sub x}Al{sub 1−x}N thin films

    SciTech Connect

    Mayrhofer, P. M.; Bittner, A.; Schmid, U.; Eisenmenger-Sittner, C.; Euchner, H.

    2013-12-16

    Doping of wurtzite aluminium nitride (AlN) with scandium (Sc) significantly enhances the piezoelectric properties of AlN. Sc{sub x}Al{sub 1−x}N thin films with different Sc concentrations (x = 0 to 0.15) were deposited by DC reactive magnetron sputtering. Infrared (IR) absorbance spectroscopy was applied to investigate the Sc concentration dependent shift of the IR active modes E{sub 1}(TO) and A{sub 1}(TO). These results are compared to ab initio simulations, being in excellent agreement with the experimental findings. In addition, IR spectroscopy is established as an economical and fast method to distinguish between thin films with a high degree of c-axis orientation and those exhibiting mixed orientations.

  2. Effect of the valence electron concentration on the bulk modulus and chemical bonding in Ta{sub 2}AC and Zr{sub 2}AC (A=Al, Si, and P)

    SciTech Connect

    Schneider, Jochen M.; Music, Denis; Sun Zhimei

    2005-03-15

    We have studied the effect of the valence electron concentration, on the bulk modulus and the chemical bonding in Ta{sub 2}AC and Zr{sub 2}AC (A=Al, Si, and P) by means of ab initio calculations. Our equilibrium volume and the hexagonal ratio (c/a) agree well (within 2.7% and 1.2%, respectively) with previously published experimental data for Ta{sub 2}AlC. The bulk moduli of both Ta{sub 2}AC and Zr{sub 2}AC increase as Al is substituted with Si and P by 13.1% and 20.1%, respectively. This can be understood since the substitution is associated with an increased valence electron concentration, resulting in band filling and an extensive increase in cohesion.

  3. Imprecision profiling.

    PubMed

    Sadler, William A

    2008-08-01

    * Imprecision profiles express precision characteristics of an assay over a range of concentration values. They can convert large quantities of potentially complex data into an easily interpreted graphical summary. * Imprecision profile estimation does not require precisely structured data. This implies that structured method evaluation data can be easily compared with, or merged with, less structured internal quality control (QC) data (or with data from any other source). * Although originally conceived for immunoassays, imprecision profiles could, in principle, be used as a summary method with any measurement system where precision varies with level of measurand. PMID:18852854

  4. Two different approaches for the prediction of in vivo plasma concentration-time profile from in vitro release data of once daily formulations of diltiazem hydrochloride.

    PubMed

    Bendas, Ehab R

    2009-09-01

    The aim of this study was to employ two different mathematical approaches: first, a convolution approach using computer software; second, a mathematical calculation exploiting Wagner-Nelson calculation to predict in vivo plasma concentration-time profile from the in vitro release study for the once daily formulations of a model drug diltiazem hydrochloride. The once daily extended release tablets (120 mg) were prepared by the wet granulation technique. Ethanol or ethanolic solutions of ethylcellulose (N22), were used as granulating agents along with hydrophilic matrix polymers like hydroxypropyl methylcellulose (HPMC) (K 15M). The granules showed satisfactory flow properties, compressibility, moisture content and drug content. All the tablet formulations showed acceptable properties and complied with pharmacopeial limits. The in vitro drug release study revealed that formula F7-T which contains drug: HPMC ratio 1:1 and 20 mg of ethylcellulose was able to sustain the drug release for 24 h and satisfied the USP dissolution limits. Fitting the in vitro drug release data to Korsmeyer-Peppas equation indicated that the mechanism of drug release could be zero-order. The capsule formulation F14-C which consists of drug: HPMC ratio 1:2, 12 mg of ethylcellulose and 20 mg of polyox 100 showed in vitro drug release similar to the tablet F7-T using the similarity factor (f 2). The mechanism of drug release could be coupled diffusion, and polymer matrix relaxation. The percent dissolved data from the two formulations were used as input function to predict the in vivo plasma data by the two approaches (Convolution by Kinetica software and Wagner-Nelson calculation). The two methods were validated by prediction of plasma data from in vitro release data of FDA approved 300 mg extended release capsule. Prediction errors were estimated for Cmax and area under the curve (AUC) to determine the validity of the methods. The percent prediction error for each parameter is not exceeding 15

  5. The effect of dopant concentration on properties of transparent conducting Al-doped ZnO thin films for efficient Cu2ZnSnS4 thin-film solar cells prepared by electrodeposition method

    NASA Astrophysics Data System (ADS)

    Mkawi, E. M.; Ibrahim, K.; Ali, M. K. M.; Farrukh, M. A.; Mohamed, A. S.

    2015-11-01

    Al-doped ZnO (AZO) thin films were potentiostatically deposited on indium tin oxide substrates. The influence of the doping level of the ZnO:Al films was investigated. The results of the X-ray diffraction and scanning electron microscopy analysis revealed that the structural properties of the AZO films were found polycrystalline with a hexagonal wurtzite-type structure along the (002) plane. The grain size of the AZO films was observed as approximately 3 μm in the film doping with 4 mol% ZnO:Al concentration. The thin films also exhibited an optical transmittance as high as 90 % in the wavelength range of 100-1,000 nm. The optical band gap increased from 3.33 to 3.45 eV. Based on the Hall studies, the lowest resistivity (4.78 × 10-3 Ω cm) was observed in the film doping with 3 mol% ZnO:Al concentration. The sheet resistant, carrier concentration and Hall mobility values were found as 10.78 Ω/ square, 9.03 × 1018 cm-3 and 22.01 cm2/v s, respectively, which showed improvements in the properties of AZO thin films. The ZnO:Al thin films were used as a buffer layer in thin-film solar cells with the structure of soda-lime glass/Mo/Cu2ZnSnS4/ZnS/ZnO/Al grid. The best solar cell efficiency was 2.3 % with V OC of 0.430 V, J SC of 8.24 mA cm-2 and FF of 68.1 %.

  6. An asymptotic expansion approach to the inverse radiative transfer problem. [to infer concentration profiles of the atmosphere from measurements made onboard a satellite

    NASA Technical Reports Server (NTRS)

    Gomberg, R. I.; Buglia, J. J.

    1979-01-01

    An iterative technique which recovers density profiles in a nonhomogeneous absorbing atmosphere is derived. The technique is based on the concept of factoring a function of the density profile into the product of a known term and a term which is not known, but whose power series expansion can be found. This series converges rapidly under a wide range of conditions. A demonstration example of simulated data from a high resolution infrared heterodyne instrument is inverted. For the examples studied, the technique is shown to be capable of extracting features of ozone profiles in the troposphere and to be particularly stable.

  7. Substitutional and Interstitial Diffusion in alpha2-Ti3Al(O)

    NASA Technical Reports Server (NTRS)

    Copland, Evan; Young, David J.; Gleeson, Brian; Jacobson, Nathan

    2007-01-01

    The reaction between Al2O3 and alpha2-Ti3Al was studied with a series of Al2O3/alpha2-Ti3Al multiphase diffusion couples annealed at 900, 1000 and 1100 C. The diffusion-paths were found to strongly depend on alpha2- Ti3Al(O) composition. For alloys with low oxygen concentrations the reaction involved the reduction of Al2O3, the formation of a gamma-TiAl reaction-layer and diffusion of Al and O into the alpha2-Ti3Al substrate. Measured concentration profiles across the interaction-zone showed "up-hill" diffusion of O in alpha2-Ti3Al(O) indicating a significant thermodynamic interaction between O and Al, Ti or both. Diffusion coefficients for the interstitial O in alpha2-Ti3Al(O) were determined independently from the interdiffusion of Ti and Al on the substitutional lattice. Diffusion coefficients are reported for alpha2-Ti3Al(O) as well as gamma-TiAl. Interpretation of the results were aided with the subsequent measurement of the activities of Al, Ti and O in alpha 2-Ti3Al(O) by Knudsen effusion-cell mass spectrometry.

  8. Probing channel temperature profiles in Al{sub x}Ga{sub 1−x}N/GaN high electron mobility transistors on 200 mm diameter Si(111) by optical spectroscopy

    SciTech Connect

    Kyaw, L. M.; Bera, L. K.; Dolmanan, S. B.; Tan, H. R.; Bhat, T. N.; Tripathy, S.; Liu, Y.; Bera, M. K.; Singh, S. P.; Chor, E. F.

    2014-08-18

    Using micro-Raman and photoluminescence (PL) techniques, the channel temperature profile is probed in Al{sub x}Ga{sub 1-x}N/GaN high electron mobility transistors (HEMTs) fabricated on a 200 mm diameter Si(111) substrate. In particular, RuO{sub x}-based gate is used due to the semitransparent nature to the optical excitation wavelengths, thus allowing much accurate thermal investigations underneath the gate. To determine the channel temperature profile in devices subjected to different electrical bias voltages, the GaN band-edge PL peak shift calibration with respect to temperature is used. PL analyses show a maximum channel temperature up to 435 K underneath the gate edge between gate and drain, where the estimated thermal resistance in such a HEMT structure is about 13.7 KmmW{sup −1} at a power dissipation of ∼10 W/mm. The temperature profiles from micro-Raman measurements are also addressed from the E{sub 2}-high optical phonon peak shift of GaN, and this method also probes the temperature-induced peak shifts of optical phonon from Si thus showing the nature of thermal characteristics at the AlN/Si substrate interface.

  9. Reduction in the concentration of cation vacancies by proper Si-doping in the well layers of high AlN mole fraction AlxGa1-xN multiple quantum wells grown by metalorganic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Chichibu, S. F.; Miyake, H.; Ishikawa, Y.; Furusawa, K.; Hiramatsu, K.

    2015-09-01

    Appropriate-amount Si-doping in the well layers significantly improved the luminescence efficiency of Al0.68Ga0.32N/Al0.77Ga0.23N multiple quantum wells. To understand the mechanisms, spatio-time-resolved cathodoluminescence measurements and self-consistent Schrödinger-Poisson calculations were carried out. The increase in the luminescence lifetime at room temperature, which reflects the decrease in the concentration of nonradiative recombination centers (NRCs), was correlated with increased terrace width of Si-doped wells. The results suggest the importance of H3SiNH2 doping-reactant formation that gives rise to enhanced decomposition of NH3 and provides wetting conditions by surface Si-N bonds, which reduce the total energy and concentration of NRCs composed of cation vacancies.

  10. An inverted AlGaAs/GaAs patterned-Ge tunnel junction cascade concentrator solar cell. Final subcontract report, 1 January 1991--31 August 1992

    SciTech Connect

    Venkatasubramanian, R.

    1993-01-01

    This report describes work to develop inverted-grown Al{sub 0.34}Ga{sub 0.66}As/GaAs cascades. Several significant developments are reported on as follows: (1) The AM1.5 1-sun total-area efficiency of the top Al{sub 0.34}Ga{sub 0.66}As cell for the cascade was improved from 11.3% to 13.2% (NREL measurement [total-area]). (2) The ``cycled`` organometallic vapor phase epitaxy growth (OMVPE) was studied in detail utilizing a combination of characterization techniques including Hall-data, photoluminescence, and secondary ion mass spectroscopy. (3) A technique called eutectic-metal-bonding (EMB) was developed by strain-free mounting of thin GaAs-AlGaAs films (based on lattice-matched growth on Ge substrates and selective plasma etching of Ge substrates) onto Si carrier substrates. Minority-carrier lifetime in an EMB GaAs double-heterostructure was measured as high as 103 nsec, the highest lifetime report for a freestanding GaAs thin film. (4) A thin-film, inverted-grown GaAs cell with a 1-sun AM1.5 active-area efficiency of 20.3% was obtained. This cell was eutectic-metal-bonded onto Si. (5) A thin-film inverted-grown, Al{sub 0.34}Ga{sub 0.66}As/GaAs cascade with AM1.5 efficiency of 19.9% and 21% at 1-sun and 7-suns, respectively, was obtained. This represents an important milestone in the development of an AlGaAs/GaAs cascade by OMVPE utilizing a tunnel interconnect and demonstrates a proof-of-concept for the inverted-growth approach.

  11. Influence of the Al concentration on the electronic properties of coupled and uncoupled AlxGa1-xAs/AlAs/AlyGa1-yAs double quantum wells

    NASA Astrophysics Data System (ADS)

    Armas, L. E. G.; da Silva, E. C. F.; Duarte, C. A.; Pagnossin, I. R.; Quivy, A. A.; Menezes, J. W.; Jacinto, C.; Seabra, A. C.; Gusev, G. M.

    2014-07-01

    Shubnikov-de Haas (SdH) and Hall measurements have been used to investigate the electron densities and mobilities in a pair of adjacent two-dimensional electron gases (2DEGs), which were confined in coupled and uncoupled AlxGa1-xAs/AlAs/AlyGa1-yAs double quantum wells (DQWs), as a function of front-gate voltage (Vg). The electron densities and mobilities of the first and second sub-bands were determined using the fast Fourier transform (FFT) in both coupled and uncoupled samples, named S1, S2 and S3, which have different aluminum (Al) content in each well. Sample S1 was illuminated in order to reach the coupled behavior. The electronic properties of the samples have been compared, showing that the electron density and mobility decrease with increasing Al content within the quantum wells (QWs). The last fact was attributed to the alloy scattering in the AlxGa1-xAs quantum well.

  12. Effects of sub-lethal concentrations of thyme and oregano essential oils, carvacrol, thymol, citral and trans-2-hexenal on membrane fatty acid composition and volatile molecule profile of Listeria monocytogenes, Escherichia coli and Salmonella enteritidis.

    PubMed

    Siroli, Lorenzo; Patrignani, Francesca; Gardini, Fausto; Lanciotti, Rosalba

    2015-09-01

    The aim of this work was to investigate the modifications of cell membrane fatty acid composition and volatile molecule profiles of Listeria monocytogenes, Salmonella enteritidis, Escherichia coli, during growth in the presence of different sub-lethal concentrations of thyme and oregano essential oils as well as carvacrol, thymol, trans-2-hexenal and citral. The results evidenced that the tested molecules induced noticeable modifications of membrane fatty acid profiles and volatile compounds produced during the growth. Although specific differences in relation to the species considered were identified, the tested compounds induced a marked increase of some membrane associated fatty acids, particularly unsaturated fatty acids, trans-isomers, and specific released free fatty acids. These findings can contribute to the comprehension of the stress response mechanisms used by different pathogenic microorganisms often involved in food-borne diseases in relation to the exposure to sub-lethal concentrations of natural antimicrobials. PMID:25842326

  13. Structural refinement, band-gap analysis and optical properties of GdAlO3 nanophosphors influenced by Dy3+ ion concentrations for white light emitting device applications

    NASA Astrophysics Data System (ADS)

    Jisha, P. K.; Naik, Ramachandra; Prashantha, S. C.; Nagaswarupa, H. P.; Nagabhushana, H.; Basavaraj, R. B.; Sharma, S. C.; Prasad, Daruka

    2016-04-01

    Nanosized GdAlO3 phosphors activated with Dy3+ were prepared by a combustion method. Synthesized phosphors were calcined at 1000 °C for 3 h in order to achieve crystallinity. Powder x-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis was used to characterize the prepared product. The orthorhombic phase was observed in the XRD pattern. The particle size of the samples was calculated as around 25 nm. The SEM images show an irregular shape of the prepared nanophosphor. Functional groups of the phosphors were examined by Fourier transform infrared (FTIR) spectroscopy. Photoluminescence (PL) properties of Dy3+ doped GdAlO3 for near-ultraviolet excitation (352 nm) were studied in order to investigate the possibility of its use in white light emitting device applications. Judd–Ofelt intensity parameters, radiative transition rate (A T) and radiative lifetimes (τ rad) were evaluated from the emission spectrum by adopting a standard procedure. The Commission International de l’Eclairage (CIE) color coordinates and correlated color temperature (CCT) are studied for the optimized phosphor. It is found that the color coordinates of Dy3+ doped GdAlO3 powders fall in the white region of the CIE diagram, and the average CCT value was found to be about 6276 K. Therefore, the present phosphor is highly useful for display applications.

  14. DESIGN ARTIFACTS IN EULERIAN REGIONAL AIR QUALITY MODELS: EVALUATION OF THE EFFECTS OF LAYER THICKNESS AND VERTICAL PROFILE CORRECTION ON SURFACE OZONE CONCENTRATIONS

    EPA Science Inventory

    Evaluation studies of the Regional Acid Deposition Model (RADM) results have revealed that there exists high bias of surface SO2 and O3 concentrations by the model, especially during nighttime hours. omparison of the RADM results with surface measurements of hourly ozone concentr...

  15. Al, Fe, and Si compounds in Tamm and Mehra-Jackson extracts from mucky-peaty-podzolic gley soil: Contents, reserves, and profile and particle-size distributions

    NASA Astrophysics Data System (ADS)

    Sokolova, T. A.; Tolpeshta, I. I.; Maksimova, Yu. G.

    2014-05-01

    Equal or comparable contents of Fe and Al extractable by Tamm and Mehra-Jackson solutions have been revealed in all the horizons of a loamy mucky-peaty-podzolic gley soil on binary deposits. The content of Si extractable by the Mehra-Jackson solution has exceeded that of oxalate-soluble Si by an order of magnitude. The distributions of Al in the Tamm solutions from the entire soil and its fractions of 1-5 and >5 μm are of accumulative type with a maximum in the mucky H horizon and a gradual decrease of the content with depth in relation with the analogous distribution of Al-organic complexes. The maximum content of oxalate-soluble Al in the clay fraction has been found in the eluvial ELg horizon, which can be due to the partial dissolution of Al hydroxide interlayers in soil chlorites. The distribution of Fe in the entire soil has two maximums, in the H horizon due to the accumulation of Fe-organic complexes and in the concretion-rich ELnn,g horizon due to the accumulation of Fe hydroxides. Depletion of oxalate-soluble Fe in the eluvial ELg horizon has been observed in all the fractions, which can be related to its mobilization and removal under strongly acidic conditions and the development of reductive processes, as well as the enrichment of the concretion-rich horizon with these compounds because of an increase in pH and the development of conditions favorable for water stagnation and Fe segregation.

  16. Determination of concentration profiles by elastic recoil detection with a ΔE-E gas telescope and high energy incident heavy ions

    NASA Astrophysics Data System (ADS)

    Stoquert, J. P.; Guillaume, G.; Hage-Ali, M.; Grob, J. J.; Ganter, C.; Siffert, P.

    1989-12-01

    The Elastic Recoil Detection (ERD) method has been used to determine the profile of a wide range of elements simultaneously in a thin layer (1μm) with a depth resolution of a few hundred Å and high sensitivity. Z separation is achieved by a ΔE(gas)-E(solid) telescope. Results for 127I (up to 240 MeV) incident ions used to profile thin films of dielectrics (SiOxNyHz), amorphous semiconductors (a-GaAs: H) and superconductors (YBaCuO, BiSrCaCuO) are reported. It has been considered previously that ERD is of interest for analysis of light elements. We show that high energy heavy incident ions extend the field of application of the ERD method to all elements with an approximately constant depth resolution and sensitivity.

  17. Circularly symmetric operation of a concentric-circle-grating, surface- emitting, AlGaAs/GaAs quantum-well semiconductor laser

    SciTech Connect

    Erdogan, T.; King, O.; Wicks, G.W.; Hall, D.G. ); Anderson, E.H. ); Rooks, M.J. )

    1992-04-20

    A surface-emitting semiconductor laser that utilizes a concentric-circle grating defined by electron-beam lithography is observed to oscillate in a circularly symmetric fashion. The laser emits a circularly symmetric beam with a total beam divergence of less than 1{degree}. Despite its broad-area geometry, the laser shows no evidence of filamentation. The laser maintains a relatively narrow wavelength spectrum approximately 1 A in width.

  18. Reduction in the concentration of cation vacancies by proper Si-doping in the well layers of high AlN mole fraction Al{sub x}Ga{sub 1–x}N multiple quantum wells grown by metalorganic vapor phase epitaxy

    SciTech Connect

    Chichibu, S. F. Ishikawa, Y.; Furusawa, K.; Miyake, H.; Hiramatsu, K.

    2015-09-21

    Appropriate-amount Si-doping in the well layers significantly improved the luminescence efficiency of Al{sub 0.68}Ga{sub 0.32}N/Al{sub 0.77}Ga{sub 0.23}N multiple quantum wells. To understand the mechanisms, spatio-time-resolved cathodoluminescence measurements and self-consistent Schrödinger-Poisson calculations were carried out. The increase in the luminescence lifetime at room temperature, which reflects the decrease in the concentration of nonradiative recombination centers (NRCs), was correlated with increased terrace width of Si-doped wells. The results suggest the importance of H{sub 3}SiNH{sub 2} doping-reactant formation that gives rise to enhanced decomposition of NH{sub 3} and provides wetting conditions by surface Si-N bonds, which reduce the total energy and concentration of NRCs composed of cation vacancies.

  19. Modeling degradation and failure of Ni-Cr-Al overlay coatings

    NASA Technical Reports Server (NTRS)

    Nesbitt, J. A.; Heckel, R. W.

    1984-01-01

    Degradation of a Ni-16Cr-25Al-0.06Zr overlay coating on a Ni-22Cr substrate was examined after oxidation accompanied by thermal cycling. Concentration/distance profiles were measured in the coating and substrate after various one-hour cycles at 1150 C. A numerical model was developed to simulate coating degradation by simultaneous oxidation and coating/substrate interdiffusion. The validity of the model was confirmed by comparison of predicted and measured concentration/distance profiles. The ability of the model to identify critical system parameters was demonstrated for the case of the initial Al and Cr content of the coating and substrate.

  20. Comparison of concentrations and profiles of polycyclic aromatic hydrocarbon metabolites in bile of fishes from offshore oil platforms and natural reefs along the California coast

    USGS Publications Warehouse

    Gale, Robert W.; Tanner, Michael J.; Love, Milton S.; Nishimoto, Mary M.; Schroeder, Donna M.

    2012-01-01

    To determine the environmental consequences of decommissioning offshore oil platforms on local and regional fish populations, contaminant loads in reproducing adults were investigated at seven platform sites and adjacent, natural sites. Specimens of three species (Pacific sanddab, Citharichthys sordidus; kelp rockfish, Sebastes atrovirens; and kelp bass, Paralabrax clathratus) residing at platforms and representing the regional background within the Santa Barbara Channel and within the San Pedro Basin were collected. Some of the most important contaminant classes related to oil operations are polycyclic aromatic hydrocarbons (PAHs) because of their potential toxicity and carcinogenicity. However, acute exposure cannot be related directly to PAH tissue concentrations because of rapid metabolism of the parent chemicals in fish; therefore, PAH metabolites in bile were measured, targeting free hydroxylated PAHs (OH-PAHs) liberated by enzymatic hydrolysis of the bound PAH glucuronides and sulfates. An ion-pairing method was developed for confirmatory analysis that targeted PAH glucuronides and sulfates. Concentrations of hydroxylated PAHs in all samples (76 fish from platforms and 64 fish from natural sites) were low, ranging from less than the limits of detection (5 to 120 nanograms per milliliter bile; 0.03 to 42 nanograms per milligram protein) to a maximum of 320 nanograms per milliliter bile (32 nanograms per milligram protein). A previously proposed dosimeter of PAH exposure in fish, 1-hydroxypyrene, was not detected at any platform site. Low concentrations of 1-hydroxypyrene were detected in 3 of 12 kelp rockfish collected from a natural reef site off Santa Barbara. The most prevalent OH-PAH, 2-hydroxyfluorene, was detected at low concentrations in seven fish of various species; of these, four were from two of the seven platform sites. The greatest concentrations of 2-hydroxyfluorene were found in three fish of various species from Platform Holly and were only

  1. Profiling the third-body wear damage produced in CoCr surfaces by bone cement, CoCr, and Ti6Al4V debris: a 10-cycle metal-on-metal simulator test.

    PubMed

    Halim, Thomas; Burgett, Michelle; Donaldson, Thomas K; Savisaar, Christina; Bowsher, John; Clarke, Ian C

    2014-07-01

    Particles of bone cement (polymethyl methacrylate), CoCr and Ti6Al4V were compared for their abrasion potential against CoCr substrates. This appears to be the first study utilizing CoCr and Ti6Al4V particulates to abrade CoCr bearings and the first study profiling the morphology of third-body abrasive wear scratches in a hip simulator. The 5 mg debris allotments (median size range 140-300 µm) were added to cups mounted both inverted and anatomically with metal-on-metal (MOM) bearings in a 10-cycle, hip simulator test. Surface abrasion was characterized by roughness indices and scratch profiles. Compared to third-body abrasion with metal debris, polymethyl methacrylate debris had minimal effect on the CoCr surfaces. In all, 10 cycles of abrasion with metal debris demonstrated that roughness indices (Ra, PV) increased approximately 20-fold from the unworn condition. The scratch profiles ranged 20-108 µm wide and 0.5-2.8 µm deep. The scratch aspect ratio (W/PV) averaged 0.03, and this very low ratio indicated that the 140 µm CoCr beads had plastically deformed to create wide but shallow scratches. There was no evidence of transfer of CoCr beads to CoCr bearings. The Ti64 particles produced similar scratch morphology with the same aspect ratio as the CoCr particulates. However, the titanium particulates also showed a unique ability to flatten and adhere to the CoCr, forming smears and islands of contaminating metal on the CoCr bearings. The morphology of scratches and metal transfer produced by these large metal particulates in the simulator appeared identical to those reported on retrieved metal-on-metal bearings. PMID:25062741

  2. Interdiffusion in the Mg-Al system and Intrinsic Diffusion in (Al3Mg2) Phase

    SciTech Connect

    Brennan, Sarah; Bermudez, Katrina; Kulkarni, Nagraj S; Sohn, Yong Ho

    2011-01-01

    Increasing use and development of lightweight Mg-alloys have led to the desire for more fundamental research in and understanding of Mg-based systems. As a strengthening component, Al is one of the most important and common alloying elements for Mg-alloys. In this study, solid-to-solid diffusion couple techniques were employed to examine the interdiffusion between pure Mg and Al. Diffusion anneals were carried out at 300 , 350 , and 400 C for 720, 360, and 240 hours, respectively. Optical and scanning electron microscopies (SEM) were employed to observe the formation of the intermetallics -Al12Mg17 and -Al3Mg2, but not -phase. Concentration profiles were determined using X-ray energy dispersive spectroscopy (XEDS). The growth constants and activation energies were determined for each intermetallic phase.

  3. Real-world automotive particulate matter and PAH emission factors and profile concentrations: Results from an urban tunnel experiment in Naples, Italy

    NASA Astrophysics Data System (ADS)

    Riccio, A.; Chianese, E.; Monaco, D.; Costagliola, M. A.; Perretta, G.; Prati, M. V.; Agrillo, G.; Esposito, A.; Gasbarra, D.; Shindler, L.; Brusasca, G.; Nanni, A.; Pozzi, C.; Magliulo, V.

    2016-09-01

    On-road particulate matter (PM) mass was measured during a sampling campaign in March of 2015 in the '4 giornate' tunnel in Naples, Italy. Two sets of samples were collected at both sides of the tunnel, each set representing the daily cycle at a 1 h time resolution. Distance-based - mass per kilometer - and fuel-based - mass per burned fuel - emission factors (EFs) were calculated using mass concentrations, traffic flow rates and wind speed as a function of fleet composition. Also, chemical analyses were performed for polycyclic aromatic hydrocarbons (PAHs). Due to the high traffic volume, particle mass concentration at the tunnel exit was always significantly elevated relative to entrance concentration; depending on the hour of the day, PM10 concentration ranged between 300 μg/m3, during the early afternoon, and 600 μg/m3 during rush hours at the tunnel exit. Correspondingly, PAHs achieved concentrations as high as 1450 ng/m3, and benzo(a)pyrene, a surely carcinogenic compound, achieved concentrations as high as 69 ng/m3, raising serious concerns in relation to population exposure close to this urban tunnel. Distance-based and fuel-based emission factors for CO2, PM10 and PAHs were estimated, but while the EF for CO2 was within the range of expected values, the present study found much higher EFs for particulate matter and PAHs. According to the national official statistics from ISPRA (the Italian Institute for the Protection and Research on Environment), derived from the COPERT database, we expected an EF for particulate matter of about 55 mg/km, but the EF estimated from measurements taken at both sides of the tunnel was about four times higher than that expected; also, benzo(a)pyrene achieved an average EF of 2.7 μg/km, about three times higher than that expected from the ISPRA database.

  4. Concentrations and profiles of bisphenol A and other bisphenol analogues in foodstuffs from the United States and their implications for human exposure.

    PubMed

    Liao, Chunyang; Kannan, Kurunthachalam

    2013-05-15

    As the concern over the safety of bisphenol A (BPA) continues to grow, this compound is gradually being replaced, in industrial applications, with compounds such as bisphenol F (BPF) and bisphenol S (BPS). Occurrence of bisphenols, including BPA and BPS, has been reported in paper products and in environmental matrices. Information on the occurrence of bisphenols, other than BPA, in foodstuffs, however, is scarce. In this study, several bisphenol analogues, including BPA, BPF, and BPS, were analyzed in foodstuffs (N = 267) collected from Albany, NY, USA, using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Foodstuffs were divided into nine categories of beverages, dairy products, fats and oils, fish and seafood, cereals, meat and meat products, fruits, vegetables, and "others". Bisphenols were found in the majority (75%) of the food samples, and the total concentrations of bisphenols (ΣBPs: sum of eight bisphenols) were in the range of below the limit of quantification (LOQ) to 1130 ng/g fresh weight, with an overall mean value of 4.38 ng/g. The highest overall mean concentration of ΣBPs was found in the "others" category, which included condiments (preserved, ready-to-serve foods). A sample of mustard (dressing) and ginger, placed in the category of vegetables, contained the highest concentrations of 1130 ng/g for bisphenol F (BPF) and 237 ng/g for bisphenol P (BPP). Concentrations of BPs in beverages (mean = 0.341 ng/g) and fruits (0.698 ng/g) were low. The predominant bisphenol analogues found in foodstuffs were BPA and BPF, which accounted for 42 and 17% of the total BP concentrations, respectively. Canned foods contained higher concentrations of individual and total bisphenols in comparison to foods sold in glass, paper, or plastic containers. On the basis of measured concentrations and daily ingestion rates of foods, the daily dietary intakes of bisphenols (calculated from the mean concentration) were estimated to be 243, 142

  5. Unexpected bismuth concentration profiles in metal-organic vapor phase epitaxy-grown Ga(As{sub 1−x}Bi{sub x})/GaAs superlattices revealed by Z-contrast scanning transmission electron microscopy imaging

    SciTech Connect

    Wood, A. W.; Babcock, S. E.; Guan, Y.; Forghani, K.; Anand, A.; Kuech, T. F.

    2015-03-01

    A set of GaAs{sub 1−x}Bi{sub x}/GaAs multilayer quantum-well structures was deposited by metal-organic vapor phase epitaxy at 390 °C and 420 °C. The precursor fluxes were introduced with the intent of growing discrete and compositionally uniform GaAs{sub 1−x}Bi{sub x} well and GaAs barrier layers in the epitaxial films. High-resolution high-angle annular-dark-field (or “Z-contrast”) scanning transmission electron microscopy imaging revealed concentration profiles that were periodic in the growth direction, but far more complicated in shape than the intended square wave. The observed composition profiles could explain various reports of physical properties measurements that suggest compositional inhomogeneity in GaAs{sub 1−x}Bi{sub x} alloys as they currently are grown.

  6. Characterisation of selected active agents regarding pKa values, solubility concentrations and pH profiles by SiriusT3.

    PubMed

    Schönherr, D; Wollatz, U; Haznar-Garbacz, D; Hanke, U; Box, K J; Taylor, R; Ruiz, R; Beato, S; Becker, D; Weitschies, W

    2015-05-01

    The aim of this work was to determine pKa values and solubility properties of 34active agents using the SiriusT3 apparatus. The selected drug substances belong to the groups of ACE-inhibitors, β-blockers, antidiabetics and lipid lowering substances. Experimentally obtained pKa and intrinsic solubility values were compared to calculated values (program ACD/ChemSketch) and pKa values to published data as well. Solubility-pH profiles were generated to visualise the substance solubility over the gastrointestinal pH range. The relationship between the solubility characteristic of a substance, its bioavailability and categorisation according to the Biopharmaceutics Classification System (BCS) was examined as well. The results showed a good agreement between experimentally obtained, calculated and published pKa values. The measured and calculated intrinsic solubility values indicated several major deviations. All solubility-pH profiles showed the expected shape and appearance for acids, bases or zwitterionic substances. The obtained results for the pKa and solubility measurements of the examined active agents may help to predict their physicochemical behaviour in vivo, and to understand the bioavailability of the substances according to their BCS categorisation. The easy and reproducible determination of pKa and solubility values makes the SiriusT3 apparatus a useful tool in early stages of drug and formulation development. PMID:25758123

  7. Effects of Ce3+ doping concentrations on microstructure and luminescent properties of Ce3+:Lu3Al5O12 (Ce:LuAG) transparent ceramics

    NASA Astrophysics Data System (ADS)

    Xu, Jian; Fan, Lingcong; Shi, Ying; Li, Junlang; Xie, Jianjun; Lei, Fang

    2014-10-01

    Ce3+ doping behaviour in range from 1.0 to 10.0 mol% on Ce:LuAG polycrystalline powders and ceramics was investigated in this paper. It was found that CeO2 would segregate as secondary phase from Ce:LuAG powders when the Ce3+ doping concentration reached to 5.0 mol% under the calcination of 1100 °C for 10 h in air. However, this “over-doped” phenomenon disappeared after the powders being densified into transparent ceramics by vacuum sintering. When the Ce3+ doping concentration was further increased into 10.0 mol%, the CeO2 segregation regions were observed in the corresponding Ce:LuAG ceramic with an elongated rod morphology. The drastic dropping of in-line optical transmittance of the 10.0 mol% Ce:LuAG ceramic demonstrated that the CeO2 secondary phase would form defects and/or electron traps at grain boundaries which embarrassed the energy transfer from host lattice to Ce3+ luminescent centers leading to its poor scintillation property.

  8. Impact of Luminal Fluid Volume on the Drug Absorption After Oral Administration: Analysis Based on In Vivo Drug Concentration-Time Profile in the Gastrointestinal Tract.

    PubMed

    Tanaka, Yusuke; Goto, Takanori; Kataoka, Makoto; Sakuma, Shinji; Yamashita, Shinji

    2015-09-01

    The objective of this study is to clarify the influence of fluid volume in the gastrointestinal (GI) tract on the oral drug absorption. In vivo rat luminal concentrations of FITC-dextran (FD-4), a nonabsorbable marker, and drugs (metoprolol and atenolol) after oral coadministration as solutions with different osmolarity were determined by direct sampling of residual water in each segment of the GI tract. The luminal FD-4 concentration after oral administration as hyposmotic solution was significantly higher than that after administration as isosmotic or hyperosmotic solution. As the change in FD-4 concentration reflects the change in the volume of luminal fluid, it indicated that the luminal volume was greatly influenced by osmolality of solution ingested orally. Then, fraction of drug absorbed (Fa) in these segments was calculated by comparing the area under the luminal concentration-time curve of FD-4 with those of drugs. Fa values of two model drugs in each GI segment decreased with increase in luminal fluid volume, and the impact of the fluid volume was marked for Fa of atenolol (a low permeable drug) than for that of metoprolol (a high permeable drug). These findings should be beneficial to assure the effectiveness and safety of oral drug therapy. PMID:25821198

  9. COMPARISON OF MODELED CONCENTRATION PROFILES USING SITE-SPECIFIC AND CONSTANT-CONDITION METEOROLOGICAL DATA FOR THE ISCLT AND PAL MODELS

    EPA Science Inventory

    Modeling atmospheric pollutant dispersion from ground-level area sources generally requires site-specific, or at least site-representative meteorological data. odels that predict annual-average concentrations as a function of radial distance and azimuthal direction accept data in...

  10. Modulation in Persistent Organic Pollutant Concentration and Profile by Prey Availability and Reproductive Status in Southern Resident Killer Whale Scat Samples.

    PubMed

    Lundin, Jessica I; Ylitalo, Gina M; Booth, Rebecca K; Anulacion, Bernadita; Hempelmann, Jennifer A; Parsons, Kim M; Giles, Deborah A; Seely, Elizabeth A; Hanson, M Bradley; Emmons, Candice K; Wasser, Samuel K

    2016-06-21

    Persistent organic pollutants (POPs), specifically PCBs, PBDEs, and DDTs, in the marine environment are well documented, however accumulation and mobilization patterns at the top of the food-web are poorly understood. This study broadens the understanding of POPs in the endangered Southern Resident killer whale population by addressing modulation by prey availability and reproductive status, along with endocrine disrupting effects. A total of 140 killer whale scat samples collected from 54 unique whales across a 4 year sampling period (2010-2013) were analyzed for concentrations of POPs. Toxicant measures were linked to pod, age, and birth order in genotyped individuals, prey abundance using open-source test fishery data, and pregnancy status based on hormone indices from the same sample. Toxicant concentrations were highest and had the greatest potential for toxicity when prey abundance was the lowest. In addition, these toxicants were likely from endogenous lipid stores. Bioaccumulation of POPs increased with age, with the exception of presumed nulliparous females. The exceptional pattern may be explained by females experiencing unobserved neonatal loss. Transfer of POPs through mobilization of endogenous lipid stores during lactation was highest for first-borns with diminished transfer to subsequent calves. Contrary to expectation, POP concentrations did not demonstrate an associated disruption of thyroid hormone, although this association may have been masked by impacts of prey abundance on thyroid hormone concentrations. The noninvasive method for measuring POP concentrations in killer whales through scat employed in this study may improve toxicant monitoring in the marine environment and promote conservation efforts. PMID:27186642

  11. Profiling of phytohormones in rice under elevated cadmium concentration levels by magnetic solid-phase extraction coupled with liquid chromatography tandem mass spectrometry.

    PubMed

    Cai, Bao-Dong; Yin, Jia; Hao, Yan-Hong; Li, Yu-Nan; Yuan, Bi-Feng; Feng, Yu-Qi

    2015-08-01

    Phytohormones, a collection of signal small molecules with various structures, regulate a series of physiological processes of plants. For instance, they regulate the growth and development, response to biotic and abiotic stresses. Quantification of trace endogenous phytohormones is essential to elucidate their molecular mechanisms in response to stresses. However, the structural and chemical diversity of phytohormones make it difficult to purify and enrich multiple phytohormones in one-step. In the current study, a method was developed to comprehensively profile phytohormones, including 8 cytokinins (CKs), indole-3-acetic acid (IAA), abscisic acid (ABA), jasmonic acid (JA) and 10 gibberellins (GAs) by Fe3O4@TiO2-based magnetic solid-phase extraction coupled with ultra-performance liquid chromatography-electrospray tandem mass spectrometry (Fe3O4@TiO2-based MSPE-UPLC-MS/MS). In the proposed method, the phytohormones in the acetonitrile extract of plant tissues were captured and purified by one-step MSPE using Fe3O4@TiO2 as a sorbent prior to UPLC-MS/MS analysis. The sensitivity, accuracy and reproducibility of the proposed analytical method were demonstrated to satisfy the profiling of multiple phytohormones in plant tissue. We then further used the Fe3O4@TiO2-based MSPE-UPLC-MS/MS method to explore the change of phytohormones in rice under Cd stress. The results showed that CKs, IAA, ABA, JA and biological active GAs all increased under Cd stress, suggesting that these phytohormones may take part in response to Cd stress. The study may promote the further understanding of the physiological functions of phytohormones in response to Cd stress. PMID:26141271

  12. Effect of Absorption Behavior of Solubilizers on Drug Dissolution in the Gastrointestinal Tract: Evaluation Based on In Vivo Luminal Concentration-Time Profile of Cilostazol, a Poorly Soluble Drug, and Solubilizers.

    PubMed

    Tanaka, Yusuke; Kubota, Atsuo; Matsuo, Akira; Kawakami, Ayaka; Kamizi, Hiroki; Mochigoe, Akane; Hiramachi, Takahiro; Kasaoka, Satoshi; Yoshikawa, Hiroshi; Nagata, Shunji

    2016-09-01

    The purpose of this study was to evaluate the effect of absorption behavior of solubilizers on drug dissolution in the gastrointestinal tract. After oral administration of FITC-dextran (FD-10), a nonabsorbable marker, and cilostazol (CZ), a low-solubility drug, with or without solubilizers (dimethyl sulfoxide [DMSO], and d-α-tocopherol polyethylene glycol 1000 succinate [TPGS]), the in vivo rat luminal concentrations of these compounds were determined by direct sampling of residual water in each segment of the gastrointestinal tract. DMSO was rapidly absorbed and not detected in the middle small intestine. Conversely, the TPGS concentration increased by 1.5- and 2-fold relative to the initial dose concentration in the middle and lower small intestine, respectively, owing to condensation. Then, normalized area under the luminal concentration-time curve of solid CZ was calculated from the luminal concentration-time profiles of FD-10 and solid CZ to evaluate in vivo dissolution behavior of CZ. The dissolution of CZ was marked when administered with TPGS compared with that when administered with DMSO, especially in the lower small intestine. This clearly indicates that absorbability of solubilizers is one of the important factors in determining the solubilizing effect. These findings may be beneficial to development of oral lipophilic drugs. PMID:27025982

  13. Fatty acid profile, carcass and meat quality traits of young Nellore bulls fed crude glycerin replacing energy sources in the concentrate.

    PubMed

    Lage, J F; Berchielli, T T; San Vito, E; Silva, R A; Ribeiro, A F; Reis, R A; Dallantonia, E E; Simonetti, L R; Delevatti, L M; Machado, M

    2014-03-01

    Carcass and meat quality traits of 60 Nellore young bulls fed diets without crude glycerin (CG); with CG replacing corn (CGc; 10% of dry matter - DM) in the concentrate; and with CG replacing soybean hull (CGsh; 10% of DM) in the concentrate were evaluated. Diets were evaluated at two concentrate levels (CLs). The CL did not affect cold carcass weight (CCW; P=0.6074), cold carcass dressing (CCD; P=0.9636), rib fat thickness (RFT; P=0.8696) and longissimus muscle area (LMA; P=0.7524). Animals fed diets with CGc or CGsh showed meat with greater deposition of monounsaturated fatty acid (MUFA; P=0.0022) and CLA (18:2 cis-9, trans-11) contents (P=0.0001) than animals fed diets without CG. The inclusion of 10% of CG in diets CGc or CGsh does not affect the carcass and meat quality traits; however, it increases the MUFA and CLA contents in beef, although these changes are very small in nutritional terms. PMID:24334035

  14. Markers of lutein and zeaxanthin status in two age groups of men and women: dietary intake, serum concentrations, lipid profile and macular pigment optical density

    PubMed Central

    2014-01-01

    Background & aims Lutein and zeaxanthin accumulate in retina (macular pigment). Their nutritional status can be assessed using dietary or biochemical markers and both have been associated with macular pigment optical density. We proposed to assess dietary and status markers of lutein and zeaxanthin in a group of healthy Spanish volunteers, considering the potential influence of age, gender and serum lipids to investigate the predictors of the macular pigment optical density. Methods Serum lutein and zeaxanthin concentrations, dietary intake and macular pigment optical density were determined in 108 healthy men and women (20–35 and 45–65 years), using high-performance liquid chromatography, 3-day food records and heterochromic flicker photometry, respectively. Mann–Whitney U-test, Spearman correlation coefficient and multivariate regression analysis were used for the statistical study. Results Serum concentrations and dietary intake of lutein plus zeaxanthin (p < 0.0001 and p = 0.001, respectively) were higher in older vs younger subjects, whereas macular pigment optical density was lower (p = 0.038). The highest correlation coefficients between intake and serum were for fruit and serum lutein (ρ = 0.452, p < 0.0001) and for fruit and lutein + zeaxanthin (ρ = 0.431, p < 0.0001) in the younger group. Macular pigment optical density correlated with serum xanthophylls (ρ = 0.223, p = 0.02) and fruit and vegetable intake (ρ = 0.350, p = 0.0002), showing highest correlations when lutein and zeaxanthin were expressed in relation to serum lipids in older subjects (ρ = 0.262, p = 0.006). Multivariate regression analysis identified age and serum lutein as major predictors of macular pigment optical density (total sample), and a coefficient of determination of 29.7% for the model including lutein + zeaxathin/cholesterol + triglycerides, sex and fruit + vegetables in the older group. Conclusions The

  15. Quantitative measurements of one-dimensional OH absolute concentration profiles in a methane/air flat flame by bi-directional laser-induced fluorescence

    NASA Astrophysics Data System (ADS)

    Yu, Xin; Yang, Zhen; Peng, Jiang-Bo; Zhang, Lei; Ma, Yu-Fei; Yang, Chao-Bo; Li, Xiao-Hui; Sun, Rui

    2015-11-01

    The one-dimensional (1D) spatial distributions of OH absolute concentration in methane/air laminar premixed flat flame under different equivalence ratios at atmospheric pressure are investigated by using bi-directional laser-induced fluorescence (LIF) detection scheme combined with the direct absorption spectroscopy. The effective peak absorption cross section and the average temperature at a height of 2 mm above the burner are obtained by exciting absorption on the Q1(8) rotational line in the A2Σ+ (ʋ‧ = 0) ← X2Π (ʋ″ = 0) at 309.240 nm. The measured values are 1.86×10-15 cm2 and 1719 K, respectively. Spatial filtering and frequency filtering methods of reducing noise are used to deal with the experimental data, and the smoothing effects are also compared using the two methods. The spatial distribution regularities of OH concentration are obtained with the equivalence ratios ranging from 0.8 to 1.3. The spatial resolution of the measured result is 84 μm. Finally, a comparison is made between the experimental result of this paper and other relevant study results. Project supported by the National Key Scientific Instrument and Equipment Development Projects of China (Grant No. 2012YQ040164), the National Natural Science Foundation of China (Grant Nos. 61275127 and 91441130), the China Postdoctoral Science Foundation (Grant No. 2014M560262), and the Postdoctoral Fellowship in Heilongjiang Province, China (Grant No. LBH-Z14074).

  16. Tropospheric Vertical Profiles of Aerosol Optical, Microphysical and Concentration Properties in the Frame of the Hygra-CD Campaign (Athens, Greece 2014): A Case Study of Long-Range Transport of Mixed Aerosols

    NASA Astrophysics Data System (ADS)

    Papayannis, Alexandros; Argyrouli, Athina; Müller, Detlef; Tsaknakis, Georgios; Kokkalis, Panayotis; Binietoglou, Ioannis; Kazadzis, Stelios; Solomos, Stavros; Amiridis, Vassilis

    2016-06-01

    Combined multi-wavelength aerosol Raman lidar and sun photometry measurements were performed during the HYGRA-CD campaign over Athens, Greece during May-June 2014. The retrieved aerosol optical properties (3 aerosol backscatter at 355-532-1064 nm and 2 aerosol extinction profiles at 355-532 nm) were used as input to an inversion code to retrieve the aerosol microphysical properties (effective radius reff and number concentration N) using regularization techniques. Additionally, the volume concentration profile was derived for fine particles using the LIRIC code. In this paper we selected a complex case study of long-range transport of mixed aerosols (biomass burning particles mixed with dust) arriving over Athens between 10-12 June 2014 in the 1.5-4 km height. Between 2-3 km height we measured mean lidar ratios (LR) ranging from 45 to 58 sr (at 355 and 532 nm), while the Ångström exponent (AE) aerosol extinction-related values (355nm/532nm) ranged between 0.8-1.3. The retrieved values of reff and N ranged from 0.19±0.07 to 0.22±0.07 μm and 460±230 to 2200±2800 cm-3, respectively. The aerosol linear depolarization ratio (δ) at 532 nm was lower than 5-7% (except for the Saharan dust cases, where δ~10-15%).

  17. An improved micro-method for the measurement of steroid profiles by APPI-LC-MS/MS and its use in assessing diurnal effects on steroid concentrations and optimizing the diagnosis and treatment of adrenal insufficiency and CAH.

    PubMed

    Stolze, Brian R; Gounden, Verena; Gu, Jianghong; Elliott, Elizabeth A; Masika, Likhona S; Abel, Brent S; Merke, Deborah P; Skarulis, Monica C; Soldin, Steven J

    2016-09-01

    Our goals were to (1) develop an improved micro-method usable for neonates for steroid profile measurements and a method to measure androsterone, a key steroid in the recently described androgen backdoor pathway together, with dehydroepiandrosterone and (2) to assess if dehydroepiandrosterone diurnal concentration fluctuations exist potentially necessitating strict adherence to time of blood sample draw and requirement of separate time-dependent reference intervals. Liquid chromatography-tandem mass spectrometry was performed with an atmospheric pressure photoionization source [1]. For each sample 50μL (100μL for the backdoor pathway) of serum was deproteinized by adding 75μL (150μL for the backdoor pathway) of acetonitrile containing the internal standards. After centrifugation, 75μL (150μL for the backdoor pathway) of supernatant was diluted with 250μL of water and injected onto a Poroshell 120 EC-C8 column (SB-C8 column for the backdoor pathway). Within-run coefficients of variation ranged from 2.4 to 10.4% and between-day coefficients of variation from 2.9 to 11.2%. Comparison studies yielded correlation coefficient between 0.97 and 1.00 with recoveries of 90% or greater. Our methods analyze a 9 steroid profile and an additional 2 steroid profile (backdoor pathway) with minimal sample volume (usable in neonates optimizing early diagnosis of endocrinopathies and genetic diseases). Low limits of quantitation make these methods ideal for steroid measurement in women and prepubertal children. As diurnal variations of dehydroepiandrosterone and other steroids [2] concentrations are clinically significant we recommend that separate reference intervals be developed for 8 am, 8 pm, and midnight sample draws. The use of this approach in improving the diagnosis of patients with adrenal insufficiency and congenital adrenal hyperplasia is discussed. PMID:26721696

  18. Translational profiling identifies a cascade of damage initiated in motor neurons and spreading to glia in mutant SOD1-mediated ALS

    PubMed Central

    Sun, Shuying; Sun, Ying; Ling, Shuo-Chien; Ferraiuolo, Laura; McAlonis-Downes, Melissa; Zou, Yiyang; Drenner, Kevin; Wang, Yin; Ditsworth, Dara; Tokunaga, Seiya; Kopelevich, Alex; Kaspar, Brian K.; Lagier-Tourenne, Clotilde; Cleveland, Don W.

    2015-01-01

    Ubiquitous expression of amyotrophic lateral sclerosis (ALS)-causing mutations in superoxide dismutase 1 (SOD1) provokes noncell autonomous paralytic disease. By combining ribosome affinity purification and high-throughput sequencing, a cascade of mutant SOD1-dependent, cell type-specific changes are now identified. Initial mutant-dependent damage is restricted to motor neurons and includes synapse and metabolic abnormalities, endoplasmic reticulum (ER) stress, and selective activation of the PRKR-like ER kinase (PERK) arm of the unfolded protein response. PERK activation correlates with what we identify as a naturally low level of ER chaperones in motor neurons. Early changes in astrocytes occur in genes that are involved in inflammation and metabolism and are targets of the peroxisome proliferator-activated receptor and liver X receptor transcription factors. Dysregulation of myelination and lipid signaling pathways and activation of ETS transcription factors occur in oligodendrocytes only after disease initiation. Thus, pathogenesis involves a temporal cascade of cell type-selective damage initiating in motor neurons, with subsequent damage within glia driving disease propagation. PMID:26621731

  19. A study of interdiffusion in beta + gamma/gamma + gamma prime Ni-Cr-Al. M.S. Thesis. Final Report

    NASA Technical Reports Server (NTRS)

    Carol, L. A.

    1985-01-01

    Ternary diffusion in the NiCrAl system at 1200 C was studied with beta + gamma/gamma + gamma prime infinite diffusion couples. Interdiffusion resulted in the formation of complex, multiphase diffusion zones. Concentration/distance profiles for Cr and Al in the phases present in the diffusion zone were measured after 200 hr. The Ni-rich portion of the NiCrAl phase diagram (1200 C) was also determined. From these data, bulk Cr and Al profiles were calculated and translated to diffusion paths on the ternary isotherm. Growth layer kinetics of the layers present in the diffusion zone were also measured.

  20. Retrieving the vertical distribution of chlorophyll a concentration and phytoplankton community composition from in situ fluorescence profiles: A method based on a neural network with potential for global-scale applications

    NASA Astrophysics Data System (ADS)

    Sauzède, R.; Claustre, H.; Jamet, C.; Uitz, J.; Ras, J.; Mignot, A.; D'Ortenzio, F.

    2015-01-01

    neural network-based method is developed to assess the vertical distribution of (1) chlorophyll a concentration ([Chl]) and (2) phytoplankton community size indices (i.e., microphytoplankton, nanophytoplankton, and picophytoplankton) from in situ vertical profiles of chlorophyll fluorescence. This method (FLAVOR for Fluorescence to Algal communities Vertical distribution in the Oceanic Realm) uses as input only the shape of the fluorescence profile associated with its acquisition date and geo-location. The neural network is trained and validated using a large database including 896 concomitant in situ vertical profiles of High-Performance Liquid Chromatography (HPLC) pigments and fluorescence. These profiles were collected during 22 oceanographic cruises representative of the global ocean in terms of trophic and oceanographic conditions, making our method applicable to most oceanic waters. FLAVOR is validated with respect to the retrieval of both [Chl] and phytoplankton size indices using an independent in situ data set and appears to be relatively robust spatially and temporally. To illustrate the potential of the method, we applied it to in situ measurements of the BATS (Bermuda Atlantic Time Series Study) site and produce monthly climatologies of [Chl] and associated phytoplankton size indices. The resulting climatologies appear very promising compared to climatologies based on available in situ HPLC data. With the increasing availability of spatially and temporally well-resolved data sets of chlorophyll fluorescence, one possible global-scale application of FLAVOR could be to develop 3-D and even 4-D climatologies of [Chl] and associated composition of phytoplankton communities. The Matlab and R codes of the proposed algorithm are provided as supporting information.

  1. Pulsatile characteristics of spontaneous growth hormone (GH) concentration profiles in boys evaluated by an ultrasensitive immunoradiometric assay: Evidence for ultradian periodicity of GH secretion

    SciTech Connect

    Goji, Katsumi )

    1993-03-01

    To investigate underlying ultradian periodicities in spontaneous circulating GH concentrations, blood samples were drawn from 15 normal short boys every 20 min over a 24-h period, and plasma GH concentrations were measured using an ultrasensitive immunoradiometric assay. The limit of detection for the GH assay was 0.01 [mu]g/L. The GH time series were analyzed using the Cluster program, Ultra program, cosinor analysis, and autocorrelation analysis. Plasma GH concentrations in 1,095 samples derived from 15 normal short boys were all within the detectable range of the assay and ranged from 0.07-52.2 [mu]g/L. Thirty-six percent of the GH values in the 1,095 samples from 15 normal short boys were below 1 [mu]g/L, and 82% of them occurred during the diurnal awakening period. Cluster analysis disclosed a total of 176 peaks in 15 normal short boys, with a mean [+-] SEM number of significant GH peaks of 12.1 [+-] 0.5/24 h. Twelve percent of the 176 peaks were below 1 [mu]g/L, and 95% of them occurred during the diurnal awakening period. In addition, Cluster analysis disclosed 161 interpulse intervals in total, with a mean [+-] SEM interval of 116.5 [+-] 4.3 min. The GH interpulse interval did not show a significant 24-h rhythm, whereas the GH peak height increased significantly at night. An independent discrete peak detection in program, Ultra, identified 12.6 [+-] 0.5 GH peaks/24 h. This result was in good agreement with that from analysis by the Cluster program (P = NS). Autocorrelation analysis revealed that GH time series were significantly autocorrelated in 9 of the 15 boys, with maximal autocorrelation coefficients at 115.5 min, on the average. The mean autocorrelation coefficient for a group of 15 normal short boys was significantly positive at a 100-min lag. These findings suggest that there could be a regularly occurring periodicity of approximately 100-120 min in the human GH time series. 18 refs., 4 figs., 1 tab.

  2. Laser ablation ICP-MS profiling and semiquantitative determination of trace element concentrations in desert tortoise shells: Documenting the uptake of elemental toxicants

    USGS Publications Warehouse

    Seltzer, M.D.; Berry, K.H.

    2005-01-01

    The outer keratin layer (scute) of desert tortoise shells consists of incrementally grown laminae in which various bioaccumulated trace elements are sequestered during scute deposition. Laser ablation ICP-MS examination of laminae in scutes of dead tortoises revealed patterns of trace elemental distribution from which the chronology of elemental uptake can be inferred. These patterns may be of pathologic significance in the case of elemental toxicants such as arsenic, which has been linked to both shell and respiratory diseases. Laser ablation transects, performed along the lateral surfaces of sectioned scutes, offered the most successful means of avoiding exogenous contamination that was present on the scute exterior. Semiquantitative determination of elemental concentrations was achieved using sulfur, a keratin matrix element, as an internal standard. The results presented here highlight the potential of laser ablation ICP-MS as a diagnostic tool for investigating toxic element uptake as it pertains to tortoise morbidity and mortality.

  3. Laser ablation ICP-MS profiling and semiquantitative determination of trace element concentrations in desert tortoise shells: documenting the uptake of elemental toxicants.

    PubMed

    Seltzer, Michaeld; Berry, Kristinh

    2005-03-01

    The outer keratin layer (scute) of desert tortoise shells consists of incrementally grown laminae in which various bioaccumulated trace elements are sequestered during scute deposition. Laser ablation ICP-MS examination of laminae in scutes of dead tortoises revealed patterns of trace elemental distribution from which the chronology of elemental uptake can be inferred. These patterns may be of pathologic significance in the case of elemental toxicants such as arsenic, which has been linked to both shell and respiratory diseases. Laser ablation transects, performed along the lateral surfaces of sectioned scutes, offered the most successful means of avoiding exogenous contamination that was present on the scute exterior. Semiquantitative determination of elemental concentrations was achieved using sulfur, a keratin matrix element, as an internal standard. The results presented here highlight the potential of laser ablation ICP-MS as a diagnostic tool for investigating toxic element uptake as it pertains to tortoise morbidity and mortality. PMID:15740773

  4. Concentration and depth profiles of elements in Si xN yH z/Si thin films produced by PECVD

    NASA Astrophysics Data System (ADS)

    Murillo, G.; Andrade, E.; Alonso, J. C.; Acosta, L.; Rocha, M. F.; Zavala, E. P.; Policroniades, R.

    2006-08-01

    Plasma enhanced chemical vapor deposition (PECVD) with SiH4/NH3 mixtures was used to produce silicon nitride thin films on silicon substrates. These types of films are commonly used as dielectrics in modern semiconductor technology; however, the incorporation of large amounts of hydrogen affects negatively their stability and electrical properties. Therefore, quantifications of the hydrogen content and chemical composition of these films are required. Forward elastic scattering using a 10 MeV 12C3+ beam was used to determine the thickness and stoichiometry of the films. Nuclear reaction analysis (NRA) using a 0.825 MeV deuterium beam was also applied to measure the low concentrations of oxygen and carbon in these films. The chemical structure of the silicon nitride layers was studied using infrared spectroscopy.

  5. Polychlorobenzenes and polychlorinated biphenyls in ash and soil from several industrial areas in North Vietnam: residue concentrations, profiles and risk assessment.

    PubMed

    Nguyen, Thi Hue; Nguyen, Thi Thu Thuy; Nguyen, Hoang Tung

    2016-04-01

    Polychlorinated benzenes (PCBzs) including penta- and hexachlorobenzene can be unintentionally formed from thermal processes in different industrial activities, and very little information is available on the contamination and emission characteristics of these new persistent organic pollutants from industries in Vietnam. In this study, contamination of PCBzs (including penta- and hexachlorobenzene, named PeCBz and HCB, respectively) and PCBs (including CB-28, 52, 101, 153, 138, 180) in fly ash, bottom ash and soil from combustion processes of waste incineration, metallurgy (steel making and zinc production) and cement production from several provinces in the Northern Vietnam, including Hai Duong, Hanoi, Bac Ninh, Hai Phong and Thai Nguyen, was preliminary investigated. The PCBzs concentrations in fly ash, bottom ash and soil ranged from 2.7 to 100 ng g(-1), from 2.7 to 159 ng g(-1) and from 0.28 to 33.9 ng g(-1), respectively. Relatively high residues of PeCBz in fly ash and bottom ash from municipal waste incinerators in some provinces from the Northern Vietnam were encountered. Total PCBs concentrations ranged from 18.0 to 8260 ng g(-1), from 1.0 to 10600 ng g(-1) and from 14.5 to 130 ng g(-1) for the fly ash, bottom ash and soil, respectively. Daily intakes of PeCBz, HCB and PCBs through soil ingestion and dermal exposure estimated for children ranged 0.33-9.93 (mean 3.14), 0.39-21.1 (mean 4.9) and 6.09-1530 ng/kg bw/day (mean 346), respectively; and these intakes were about 4.7-5.4 times higher than those estimated for adult. The intakes of PeCBz and HCB were relatively low, while those for PCBs exceeded WHO TDI for some samples. PMID:26049895

  6. Effects of aluminum oxide (Al2O3) nanoparticles on ECG, myocardial inflammatory cytokines, redox state, and connexin 43 and lipid profile in rats: possible cardioprotective effect of gallic acid.

    PubMed

    El-Hussainy, El-Hussainy M A; Hussein, Abdelaziz M; Abdel-Aziz, Azza; El-Mehasseb, Ibrahim

    2016-08-01

    The objectives of present study were to examine the effects of aluminum oxide (Al2O3) nanoparticles on myocardial functions, electrical activities, morphology, inflammation, redox state, and myocardial expression of connexin 43 (Cx43) and the effect of gallic acid (GA) on these effects in a rat animal model. Forty male albino rats were divided into 4 equal groups: the control (normal) group; the Al2O3 group, rats received Al2O3 (30 mg·kg(-1), i.p.) daily for 14 days; the nano-alumina group, rats received nano-alumina (30 mg·kg(-1), i.p.) daily for 14 days; and the nano-alumina + GA group, rats received GA (100 mg·kg(-1) orally once daily) for 14 days before nano-alumina administration. The results showed disturbed ECG variables and significant increases in serum levels of LDH, creatine phosphokinase (CPK), CK-MB, triglycerides (TGs), cholesterol and LDL, nitric oxide (NO), and TNF-α and myocardial concentrations of NO, TNF-α, and malondialdehyde (MDA), with significant decreases in serum HDL and myocardial GSH, SOD, catalase (CAT), and Cx43 expression in the nano-alumina group. Pretreatment with GA improved significantly all parameters except serum and myocardial NO. We concluded that chronic administration of Al2O3 NPs caused myocardial dysfunctions, and pretreatment with GA ameliorates myocardial injury induced by nano-alumina, probably through its hypolipidaemic, anti-inflammatory, and antioxidant effects and upregulation of Cx43 in heart. PMID:27191243

  7. Concentration profiling of minerals in iliac crest bone tissue of opium addicted humans using inductively coupled plasma and discriminant analysis techniques.

    PubMed

    Mani-Varnosfaderani, Ahmad; Jamshidi, Mahbobeh; Yeganeh, Ali; Mahmoudi, Mani

    2016-02-20

    Opium addiction is one of the main health problems in developing countries and induces serious defects on the human body. In this work, the concentrations of 32 minerals including alkaline, heavy and toxic metals have been determined in the iliac crest bone tissue of 22 opium addicted individuals using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The bone tissues of 30 humans with no physiological and metabolomic diseases were used as the control group. For subsequent analyses, the linear and quadratic discriminant analysis techniques have been used for classification of the data into "addicted" and "non-addicted" groups. Moreover, the counter-propagation artificial neural network (CPANN) has been used for clustering of the data. The results revealed that the CPANN is a robust model and thoroughly classifies the data. The area under the curve for the receiver operating characteristic curve for this model was more than 0.91. Investigation of the results revealed that the opium consumption causes a deficiency in the level of Calcium, Phosphate, Potassium and Sodium in iliac crest bone tissue. Moreover, this type of addiction induces an increment in the level of toxic and heavy metals such as Co, Cr, Mo and Ni in iliac crest tissue. The correlation analysis revealed that there were no significant dependencies between the age of the samples and the mineral content of their iliac crest, in this study. The results of this work suggest that the opium addicted individuals need thorough and restricted dietary and medical care programs after recovery phases, in order to have healthy bones. PMID:26717018

  8. Visualization of Steady-State Ionic Concentration Profiles Formed in Electrolytes during Li-Ion Battery Operation and Determination of Mass-Transport Properties by in Situ Magnetic Resonance Imaging.

    PubMed

    Krachkovskiy, Sergey A; Bazak, J David; Werhun, Peter; Balcom, Bruce J; Halalay, Ion C; Goward, Gillian R

    2016-06-29

    Accurate modeling of Li-ion batteries performance, particularly during the transient conditions experienced in automotive applications, requires knowledge of electrolyte transport properties (ionic conductivity κ, salt diffusivity D, and lithium ion transference number t(+)) over a wide range of salt concentrations and temperatures. While specific conductivity data can be easily obtained with modern computerized instrumentation, this is not the case for D and t(+). A combination of NMR and MRI techniques was used to solve the problem. The main advantage of such an approach over classical electrochemical methods is its ability to provide spatially resolved details regarding the chemical and dynamic features of charged species in solution, hence the ability to present a more accurate characterization of processes in an electrolyte under operational conditions. We demonstrate herein data on ion transport properties (D and t(+)) of concentrated LiPF6 solutions in a binary ethylene carbonate (EC)-dimethyl carbonate (DMC) 1:1 v/v solvent mixture, obtained by the proposed technique. The buildup of steady-state (time-invariant) ion concentration profiles during galvanostatic experiments with graphite-lithium metal cells containing the electrolyte was monitored by pure phase-encoding single point imaging MRI. We then derived the salt diffusivity and Li(+) transference number over the salt concentration range 0.78-1.27 M from a pseudo-3D combined PFG-NMR and MRI technique. The results obtained with our novel methodology agree with those obtained by electrochemical methods, but in contrast to them, the concentration dependences of salt diffusivity and Li(+) transference number were obtained simultaneously within the single in situ experiment. PMID:27250238

  9. Concentrator Systems

    NASA Astrophysics Data System (ADS)

    Luque-Heredia, Ignacio; Luque, Antonio

    2015-10-01

    The following sections are included: * Introduction * The early development of CPV * Concentrator solar cells * Optics for photovoltaic concentrators * Photovoltaic concentration modules * Tracking systems for photovoltaic concentration * High-concentration systems * Rating and performance * Cost considerations * Conclusions * References

  10. Concentration and relaxation depth profiles of In{sub x}Ga{sub 1-x}As/GaAs and GaAs{sub 1-x}P{sub x}/GaAs graded epitaxial films studied by x-ray diffraction

    SciTech Connect

    Benediktovitch, A.; Ulyanenkov, A.; Rinaldi, F.; Saito, K.; Kaganer, V. M.

    2011-07-15

    A method is proposed to determine the concentration and relaxation depth profiles in graded epitaxial films from x-ray reciprocal space maps (RSMs). Various approximations in the kinematical x-ray diffraction from epitaxial films with the misfit dislocation density depth profile are developed. We show that a symmetric and an asymmetric RSM, or two asymmetric RSMs, contain enough information to obtain the concentration, relaxation, and lattice tilt depth profiles without any additional assumptions. The proposed approach is applied to In{sub x}Ga{sub 1-x}As/GaAs and GaAs{sub 1-x}P{sub x}/GaAs epitaxial graded films. The reconstructed concentration and dislocation density depth profiles are found to be in an agreement with the ones expected from the growth conditions.

  11. Interdiffusion between the L1(2) trialuminides Al66Ti25Mn9 and Al67Ti25Cr8

    NASA Technical Reports Server (NTRS)

    Kumar, K. S.; Whittenberger, J. D.

    1992-01-01

    Concentration-distance profiles obtained from Al66Ti25Mn9/Al67Ti25Cr8 diffusion couples are used to determine the interdiffusion coeffients in the temperature range 1373-1073 K. The couples are treated as pseudobinaries, and the diffusion coefficients are determined using the Matano approach. The results are then used to compute the activation energies for diffusion, and a comparison is made with some existing data for the activation energy for creep of Al22Ti8Fe3.

  12. Interdiffusion in. beta. phase Cu--Al alloys

    SciTech Connect

    Romig, A.D. Jr.

    1983-06-01

    The diffusion behavior of ..beta.. phase Cu--Al has been studied at 800, 850, and 950 /sup 0/C using the experimental approach and analysis scheme of Kirkendall and Darken. Diffusion couples were made using the window frame technique and concentration profiles were determined by electron probe microanalysis. The chemical diffusion coefficient, D was found to be D = 0.65 exp(-42200/RT) cm/sup 2//s. The diffusivity was observed to be independent of composition over the range 11--13 wt. % Al. The self-diffusion coefficients D/sub Cu/ and D/sub Al/ were determined to be D/sub Al/ = 0.13 exp(-38900/RT) cm/sup 2//s and D/sub Cu/ = 2.2 exp(-43400/RT) cm/sup 2//s. All activation energies are in calories/mole.

  13. Capillarity Effect Controlled Precipitate Growth at the Grain Boundary of Long-Term Aging Al 5083 Alloy

    NASA Astrophysics Data System (ADS)

    Yi, Gaosong; Free, Michael L.; Zhu, Yakun; Derrick, Alexander T.

    2014-10-01

    A model was developed to predict thickness and continuity of β phase (Al3Mg2) formed at grain boundaries of long-term aged Al 5083 alloy. In this model, a variable collector plate mechanism was adopted at the early stage of aging, then, at about 1 month (), the model transitions to a constant collector plate mechanism. Two concentration profiles of Mg, one for a semi-infinite bulk at short diffusion distances and one for a finite slab at long diffusion distances ( of the grain size), were applied to this model for different aging times. Capillarity effects were used to determine the morphology of β phase at the grain boundary. Combining different collector plate mechanisms and Mg concentration profiles, the whole β phase growth process was divided into three stages (short-term Mg concentration profile-variable collector plate, short-term Mg concentration profile-constant collector plate, and long-term Mg concentration profile-constant collector plate). Finally, the model was solved numerically. Experimental results of β phase length and thickness were obtained using transmission electron microscopy (TEM) images of Al 5083 aged at 343 K (70 °C) for different thermal exposure times. Modeling results of β phase thickness and continuity agree well with experimental observations.

  14. Effects of Graded Levels of Chromium Methionine on Performance, Carcass Traits, Meat Quality, Fatty Acid Profiles of Fat, Tissue Chromium Concentrations, and Antioxidant Status in Growing-Finishing Pigs.

    PubMed

    Tian, Yao-Yao; Gong, Li-Min; Xue, Jian-Xiang; Cao, Jun; Zhang, Li-Ying

    2015-11-01

    A 97-day feeding trial was conducted to investigate the effects of dietary chromium methionine (CrMet) on performance, carcass traits, meat quality, fatty acid profiles of fat, tissue chromium concentrations, and antioxidant status in growing-finishing pigs. A total of 180 crossbred pigs with a mean initial body weight (BW) 30.18 ± 0.28 kg were allotted to 5 treatments with 6 replicates per treatment and 6 pigs per pen in a randomized complete block design based on BW and sex. Treatments were added with 0 (control), 100, 200, 400, and 800 μg/kg chromium as CrMet. Blood samples were obtained from the anterior vena cava on days 97. Carcass characteristics, pork quality, and tissue chromium concentration data were collected from one pig per pen. The results indicated that supplemental CrMet did not significantly affect growth performance, carcass traits, or meat amino acid profiles. Chromium at 100, 400, and 800 μg/kg decreased drip loss but increased shear force (P < 0.05). Pigs fed 100 or 400 μg/kg had a higher 24-h pH than the control (P < 0.05). While meat color, muscle moisture, crude protein, or crude fat were not affected by CrMet. Supplemental 800 μg/kg chromium reduced C18:0 levels in belly fat (P < 0.05), and chromium supplementation increased cis-9, trans 11-conjugated linoleic acid levels linearly (P < 0.05). Dietary CrMet supplementation increased serum, kidney, and muscle chromium contents (P < 0.05) but did not affect liver chromium contents. Besides, tissue chromium concentrations were increased linearly with increased chromium dosage (P < 0.05). Chromium at 400 μg/kg increased serum glutathione peroxidase activities (P < 0.05), and chromium at 800 μg/kg decreased serum total antioxidant capacity levels (P < 0.05). Nevertheless, liver and kidney antioxidant status were not significantly affected by CrMet. These results indicated that dietary supplementation CrMet did not significantly influence growth

  15. Impurity Diffusion Coefficients of Al and Zn in Mg Determined from Solid-to-Solid Diffusion Couples

    SciTech Connect

    Kammerer, Catherine; Kulkarni, Nagraj S; Warmack, Robert J Bruce; Perry, Kelly A; Belova, Irina; Murch, Prof. Graeme; Sohn, Yong Ho

    2013-08-01

    Increasing use and development of lightweight Mgalloys have led to the desire for more fundamental research in and understanding of Mg-based systems. As property enhancing components, Al and Zn are two of the most important and common alloying elements for Mg-alloys. We have investigated the concentration dependent interdiffusion of Al and Zn in Mg using diffusion couples of pure polycrystalline Mg mated to Mg solid solutions containing either <9 at.% Al or <3 at.% Zn. Concentration profiles were determined by electron micro-probe microanalysis of the diffusion zone. The interdiffusion coefficients were determined by the classical Boltzmann-Matano method within the Mg solid solution. As the concentration of Al or Zn approaches the dilute ends, we employ an analytical approach based on the Hall method to estimate the impurity diffusion coefficients. Results of Al and Zn impurity diffusion in Mg are reported and compared to published impurity diffusion coefficients typically determined by thin film techniques.

  16. ALS - resources

    MedlinePlus

    Resources - ALS ... The following organizations are good resources for information on amyotrophic lateral sclerosis : Muscular Dystrophy Association -- mda.org/disease/amyotrophic-lateral-sclerosis National Amyotrophic Lateral Sclerosis (ALS) Registry -- ...

  17. ALS Association

    MedlinePlus

    ... ALS. Find Out How Our Mission Leading the fight to treat and cure ALS through global research ... you participate, advocate, and donate, you advance the fight to find the cure and lead us toward ...

  18. Cloud Condensation Nuclei Profile Value-Added Product

    SciTech Connect

    McFarlane, S; Sivaraman, C; Ghan, S

    2012-10-08

    The cloud condensation nuclei (CCN) concentration at cloud base is the most relevant measure of the aerosol that influences droplet formation in clouds. Since the CCN concentration depends on supersaturation, a more general measure of the CCN concentration is the CCN spectrum (values at multiple supersaturations). The CCN spectrum is now measured at the surface at several fixed ARM sites and by the ARM Mobile Facility (AMF), but is not measured at the cloud base. Rather than rely on expensive aircraft measurements for all studies of aerosol effects on clouds, a way to project CCN measurements at the surface to cloud base is needed. Remote sensing of aerosol extinction provides information about the vertical profile of the aerosol, but cannot be directly related to the CCN concentration because the aerosol extinction is strongly influenced by humidification, particularly near cloud base. Ghan and Collins (2004) and Ghan et al. (2006) propose a method to remove the influence of humidification from the extinction profiles and tie the “dry extinction” retrieval to the surface CCN concentration, thus estimating the CCN profile. This methodology has been implemented as the CCN Profile (CCNPROF) value-added product (VAP).

  19. Al and Zn Impurity Diffusion in Binary and Ternary Magnesium Solid-Solutions

    SciTech Connect

    Kammerer, Catherine; Kulkarni, Nagraj S; Warmack, Robert J Bruce; Sohn, Yong Ho

    2014-01-01

    Magnesium alloys are considered for implementation into structural components where energy-efficiency and light-weighting are important. Two of the most common alloying elements in magnesium alloys are Aluminum and Zinc. The present work examines impurity diffusion coefficients of Al and Zn in Mg(Zn) and Mg(Al) binary solid solutions, respectively. Experimental investigation is carried out with ternary diffusion couples with polycrystalline alloys. Concentration profiles were measured by electron microprobe micro-analysis and the impurity diffusion coefficients were determined by the Hall Method. Results of Al and Zn impurity diffusion in Mg solid solutions are reported, and examined as a function of composition of Mg solid solution.

  20. Oxide formation on NbAl{sub 3} and TiAl due to ion implantation of {sup 18}O

    SciTech Connect

    Hanrahan, R.J. Jr.; Verink, E.D. Jr.; Withrow, S.P.; Ristolainen, E.O.

    1993-12-31

    Surface modification by ion implantation of {sup 18}O ions was investigated as a technique for altering the high-temperature oxidation of aluminide intermetallic compounds and related alloys. Specimens of NbAl{sub 3} and TiAl were implanted to a dose of 1 {times} 10{sup 18} ions/cm{sup 2} at 168 keV. Doses and accelerating energies were calculated to obtain near-stoichiometric concentrations of oxygen. Use of {sup 18}O allowed the implanted oxygen profiles to be measured using secondary ion mass spectroscopy (SIMS). The near surface oxides formed were studied using x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy. Specimens were also examined using x-ray diffraction and SEM. This paper presents results for specimens examined in the as-implanted state. The oxide formed due to implantation is a layer containing a mixture of Nb or Ti and amorphous Al oxides.

  1. Interdiffusion and Intrinsic Diffusion in the Mg-Al System

    SciTech Connect

    Brennan, Sarah; Bermudez, Katrina; Sohn, Yong Ho; Kulkarni, Nagraj S

    2012-01-01

    Solid-to-solid diffusion couples were assembled and annealed to examine the diffusion between pure Mg (99.96%) and Al (99.999%). Diffusion anneals were carried out at 300 , 350 , and 400 C for 720, 360, and 240 hours, respectively. Optical and scanning electron microscopes were utilized to identify the formation of the intermetallic phases, -Al12Mg17 and -Al3Mg2 and absence of the -phase in the diffusion couples. Thicknesses of the -Al12Mg17 and -Al3Mg2 phases were measured and the parabolic growth constants were calculated to determine the activation energies for the growth, 165 and 86 KJ/mole, respectively. Concentration profiles were determined with electron microprobe analysis using pure elemental standards. Composition-dependent interdiffusion coefficients in Mg-solid solution, -Al12Mg17 and - Al3Mg2 and Al-solid solutions were calculated based on the Boltzmann-Matano analysis. Average effective interdiffusion coefficients for each phase were also calculated, and the magnitude was the highest for the -Al3Mg2 phase, followed by -Al12Mg17, Al-solid solution and Mg-solid solution. Intrinsic diffusion coefficients based on Huemann s analysis (e.g., marker plane) were determined for the ~38 at.% Mg in the -Al3Mg2 phase. Activation energies and the pre-exponential factors for the inter- and intrinsic diffusion coefficients were calculated for the temperature range examined. The -Al3Mg2 phase was found to have the lowest activation energies for growth and interdiffusion among all four phases studied. At the marker location in the -Al3Mg2 phase, the intrinsic diffusion of Al was found to be faster than that of Mg. Extrapolations of the impurity diffusion coefficients in the terminal solid solutions were made and compared to the available self- and impurity diffusion data from literature. Thermodynamic factor, tracer diffusion coefficients and atomic mobilities at the marker plane composition were approximated using available literature values of Mg activity in the -Al

  2. The effects of the supplementation of Bacillus subtilis RX7 and B2A strains on the performance, blood profiles, intestinal Salmonella concentration, noxious gas emission, organ weight and breast meat quality of broiler challenged with Salmonella typhimurium.

    PubMed

    Park, J H; Kim, I H

    2015-04-01

    An experiment was conducted to evaluate the effects of B. subtilis RX7 and B. subtilis B2A on growth performance, blood profiles, intestinal Salmonella population, noxious gas emission, organ weight and breast meat quality of broilers under S. typhimurium challenge. A total of 120, one-day-old Ross 308 male broiler chicks were assigned to four dietary treatments, composed of six replications, with five birds per replication, for 10 day. The dietary treatment groups were negative control (NC; no antibiotic, no B. subtilis), positive control (PC; NC + 0.1% virginiamycin), B. subtilis RX7 (NC + 0.1% B. subtilis RX7 1.0 × 10(9) cfu/g) and B. subtilis B2A (NC + 0.1% B. subtilis 1.0 × 10(9) cfu/g). All birds were orally challenged with 2 ml suspension, containing 10(4) cfu/ml of S. typhimurium KCCM 40253. Results indicated that the body weight gain, feed intake and feed conversion did not differ, among all comparative treatments. Serum haptoglobin concentration was lower in Bacillus treatments (RX7 + B2A) than the NC treatment (p < 0.05). Intestinal and excreta Salmonella number, and excreta ammonia gas emission in the PC treatment or Bacillus treatments, was lower than the NC treatment (p < 0.05). Breast pH, colour and water-holding capacity were not affected by supplementation of B. subtilis RX7 and B2A. However, drip loss at 1 day post-slaughter from birds fed with B. subtilis RX7 and B2A decreased, compared with the positive control birds (p < 0.05). Relative gizzard weights of birds fed B. subtilis RX7 and B2A were significantly higher than the NC birds under S. typhimurium challenge. It is concluded from the results that B. subtilis RX7 and B2A increased the gizzard weight and decreased the intestinal and excreta Salmonella population and excreta ammonia gas, and drip loss of breast meat after being stored for 1 day, under stress caused by the S. typhimurium challenge. PMID:25244020

  3. Meteoric 10Be in soil profiles - A global meta-analysis

    NASA Astrophysics Data System (ADS)

    Graly, Joseph A.; Bierman, Paul R.; Reusser, Lucas J.; Pavich, Milan J.

    2010-12-01

    In order to assess current understanding of meteoric 10Be dynamics and distribution in terrestrial soils, we assembled a database of all published meteoric 10Be soil depth profiles, including 104 profiles from 27 studies in globally diverse locations, collectively containing 679 individual measurements. This allows for the systematic comparison of meteoric 10Be concentration to other soil characteristics and the comparison of profile depth distributions between geologic settings. Percent clay, 9Be, and dithionite-citrate extracted Al positively correlate to meteoric 10Be in more than half of the soils where they were measured, but the lack of significant correlation in other soils suggests that no one soil factor controls meteoric 10Be distribution with depth. Dithionite-citrate extracted Fe and cation exchange capacity are only weakly correlated to meteoric 10Be. Percent organic carbon and pH are not significantly related to meteoric 10Be concentration when all data are complied. The compilation shows that meteoric 10Be concentration is seldom uniform with depth in a soil profile. In young or rapidly eroding soils, maximum meteoric 10Be concentrations are typically found in the uppermost 20 cm. In older, more slowly eroding soils, the highest meteoric 10Be concentrations are found at depth, usually between 50 and 200 cm. We find that the highest measured meteoric 10Be concentration in a soil profile is an important metric, as both the value and the depth of the maximum meteoric 10Be concentration correlate with the total measured meteoric 10Be inventory of the soil profile. In order to refine the use of meteoric 10Be as an estimator of soil erosion rate, we compare near-surface meteoric 10Be concentrations to total meteoric 10Be soil inventories. These trends are used to calibrate models of meteoric 10Be loss by soil erosion. Erosion rates calculated using this method vary based on the assumed depth and timing of erosional events and on the reference data selected.

  4. Efficient calculation of general Voigt profiles

    NASA Astrophysics Data System (ADS)

    Cope, D.; Khoury, R.; Lovett, R. J.

    1988-02-01

    An accurate and efficient program is presented for the computation of OIL profiles, generalizations of the Voigt profile resulting from the one-interacting-level model of Ward et al. (1974). These profiles have speed dependent shift and width functions and have asymmetric shapes. The program contains an adjustable error control parameter and includes the Voigt profile as a special case, although the general nature of this program renders it slower than a specialized Voigt profile method. Results on accuracy and computation time are presented for a broad set of test parameters, and a comparison is made with previous work on the asymptotic behavior of general Voigt profiles.

  5. Thermal stability of porcine pepsin influenced by Al(III) ion: DSC study

    NASA Astrophysics Data System (ADS)

    Pavelkić, V. M.; Beljanski, M. V.; Antić, K. M.; Babić, M. M.; Brdarić, T. P.; Gopčević, K. R.

    2011-12-01

    Differential scanning calorimetry (DCS) has been used to determine thermodynamic profile of pepsin and the in vitro effect of Al(III) ions. Thermograms of pepsin unfolding in the presence and absence of aluminum were used to determine the binding constant, K L, in the pepsin-aluminium model system. The thermodynamic parameters were derived from DSC profiles at different ligand concentrations (1, 5 and 10 mM). The temperatures of thermal transitions ( T m), calorimetric (Δ H cal) and van't Hoff enthalpy (Δ H VH), Gibbs free energy, Δ(Δ G), of Al(III) binding to pepsin, as well as an average number of ligands bound to the native protein, were obtained from DSC profiles too. Temperature-dependent changes in the protein structure were also monitored by native PAGE electrophoresis. Increasing the temperature causes the decrease in electrophoretic mobility. Increase in concentration of Al(III) decelerate the migration of pepsin samples on concentration dependent manner. Analysis showed that ligand binding increases thermal stability of protein.

  6. Reconstructing the Growth History of Bubbles in Magma from Preserved Volatile Concentrations in Glass

    NASA Astrophysics Data System (ADS)

    McIntosh, I. M.; Llewellin, E. W.; Humphreys, M.; Larsen, J. F.; Blower, J. D.

    2010-12-01

    Volcanic eruptions are driven by the nucleation and growth of bubbles that are formed when volatile species (particularly water) exsolve from magma. Once nucleated, bubbles may continue to grow through a combination of diffusion of volatiles from the melt and decompressive expansion. The kinetics of bubble formation and growth exert a critical influence on eruption dynamics, particularly on the explosivity of the eruption; consequently, numerical models of volcanic eruptions are sensitive to the choice of bubble growth model. We present preliminary results of analyses of experimentally-decompressed phonolite and rhyolite samples, which provide data against which bubble growth models can be validated. Data interpretation is supported by numerical modelling of the growth of isolated and paired bubbles in three-dimensions. Previous numerical modelling of bubble growth has demonstrated the importance of the dynamic feedback between the concentration of water in the melt, its diffusivity, and the viscosity of the melt shell in which the bubble grows (e.g. Blower et al., 2001). Diffusion of water, therefore, not only alters the water concentration profile surrounding the bubble, but is itself modified by the resulting concentration profile. This concentration profile may be preserved when the magma is quenched to glass. We adapt the technique of Humphreys et al (2008) to extract sub-micron resolution water concentration data from backscatter SEM images of volcanic glasses by using greyscale variation as a proxy for water content. The profiles are calibrated using SEM-Raman and FTIR. We present preliminary two-dimensional maps of water concentration around isolated bubbles and bubble-pairs in synthetically hydrated and decompressed samples of volcanic glass. To support the interpretation of the data, we have developed a finite element model of bubble growth, which couples volatile diffusion with concentration dependent viscosity and melt hydrodynamics around the growing

  7. Peatlands as Dynamic Biogeochemical Ecotones: Elemental Concentrations, Stoichiometries and Accumulation in Peatland Soils of Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Moore, T. R.; Wang, M.; Talbot, J.; Riley, J. L.

    2015-12-01

    Peatlands act as biogeochemical interfaces between terrestrial and aquatic systems and are 'hotspots', particularly for carbon cycling and the accumulation of nutrients and other elements within the peat profile. This results in storage of substantial amounts of carbon, nutrients and metals, particularly in northern peatlands. Using a data base of over 400 peat profiles and 1700 individual peat samples from bog, fen and swamp sites in Ontario, Canada, we examine the profile concentrations of C, N, P, Ca, Mg, K, Hg, Pb, As, Cu, Mn, Zn, Fe and Al, and estimate the storage and accumulation of these elements. We show how these profiles, spatial patterns, stoichiometries and accumulation rates are controlled by biogeochemical processes and influenced by geochemical setting, hydrology, atmospheric input and pollution, and ecological and microbial transformations.

  8. Mg-doping transients during metalorganic vapor phase epitaxy of GaAs and AlGaInP

    NASA Astrophysics Data System (ADS)

    Kondo, Makoto; Anayama, Chikashi; Sekiguchi, Hiroshi; Tanahashi, Toshiyuki

    1994-08-01

    We studied magnesium-doping transients during metalorganic vapor phase epitaxy of GaAs and (Al(x)Ga(1-x))(0.5)In(0.5)P (0 less than or = x less than or = 0.7). We examined the transient of Mg concentration depth profile through epitaxial layers when Mg precursors are initially injected into the reactor (doping delay). We found that increasing the Al composition of epitaxial layers, i.e., increasing the mole fraction of Al precursors in the reactor, significantly reduces the Mg-doping delay. We obtained this result for both trimethylaluminum (TMAl) and triethylaluminum (TEAl). We quantitatively modeled this phenomenon based on the competitive adsorption of Mg and Al precursors on the internal surface of the reactor. Our model also explains that the Mg concentration in epitaxial layers increases either linearly or superlinearly with the Mg precursor input, depending on the length of the doping delay.

  9. Stimulated emission in AlGaN/AlGaN quantum wells with different Al content

    NASA Astrophysics Data System (ADS)

    Mickevičius, J.; Jurkevičius, J.; Kazlauskas, K.; Žukauskas, A.; Tamulaitis, G.; Shur, M. S.; Shatalov, M.; Yang, J.; Gaska, R.

    2012-02-01

    Stimulated emission (SE) is studied in AlGaN/AlGaN multiple quantum wells (MQWs) with different Al content grown on sapphire substrate. The spectra of spontaneous and stimulated emission and their transformations with increasing temperature as well as stimulated emission thresholds were measured in the temperature range from 8 to 300 K. Phonon-assisted band broadening in low-Al-content MQWs and double-scaled potential profile in high-Al-content MQWs were observed in the samples and linked with carrier localization conditions. The temperature dependence of the stimulated emission threshold was similar in the samples where the stimulated transitions occur between extended states and in the samples where the transitions occur in localized states. The stimulated emission threshold depends predominantly on the density of nonradiative recombination centers.

  10. Leadership Profiles.

    ERIC Educational Resources Information Center

    Teach, Beverly; And Others

    1994-01-01

    Presents profiles of two leaders in the field of educational media and technology: Carolyn Guss and Mendel Sherman, both retired professors from Indiana University's program in Information Systems Technology. (KRN)

  11. Pioneer Profile.

    ERIC Educational Resources Information Center

    Butcher, Channa Beth

    1987-01-01

    Profiles Herbert A. Sweet, founder and director of Acorn Farms Day Camp (Indiana) for 44 years. Includes reminiscences about the camp's program, staffing, food, World War II, affiliation with the American Camping Association, and camps/directors of today. (NEC)

  12. Concentrating Radioactivity

    ERIC Educational Resources Information Center

    Herrmann, Richard A.

    1974-01-01

    By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

  13. Improved tribological behavior of boron implanted Ti-6Al-4V

    SciTech Connect

    Baker, N.P.; Walter, K.C.; Nastasi, M.

    1998-03-01

    Boron implanted of Ti6Al4V has been conducted at combinations of 32 and 40 keV to supplement that done previously at 75 keV. Shallower boron depth profiles with higher B-concentrations in the Ti64 surface have been obtained by tailoring the combinations of ion energy and dose. This work used three different ion energy and dose combinations of 4 {times} 10{sup 17} B-at/cm{sup 2} at 40 keV plus 2 {times} 10{sup 17} B-at/cm{sup 2} at 32 keV, 4 {times} 10{sup 17} B-at/cm{sup 2} at 40 keV, and 4 {times} 10{sup 17} B-at/cm{sup 2} at 32 keV plus 2 {times} 10{sup 17} B-at/cm{sup 2} at 40 keV. Comparisons are made between Ti6Al4V with a shallow implanted boron depth profile, Ti6Al4V with a deeper boron depth profile and nitrogen implanted using a plasma source ion implantation process. It has been previously shown that while boron implanted Ti64 has a {approximately} 30% higher surface hardness than nitrogen implanted Ti64, the N-implantation reduced the wear coefficient of Ti64 by 25--120x, while B-implantation reduced the wear coefficient by 6.5x or less. The results show that no significant improvement is made in the wear resistance of boron implanted Ti6Al4V by increasing the concentration of boron at the surface from approximately 10% to 43%. Transmission electron microscopy (TEM) and selected area diffraction (SAD) indicated the formation of crystalline TiB in the implanted surface layer. Shallower depth profiles result in reductions of the Ti6Al4V wear coefficient by 6.5x or less which is the same result obtained earlier with the deeper boron depth profile. Surface hardness of Ti6Al4V with shallower boron depth profiles was improved approximately 10% compared to the results previously acquired with deeper boron depth profiles.

  14. Al Composites

    NASA Astrophysics Data System (ADS)

    Chandanayaka, Tharaka; Azarmi, Fardad

    2014-05-01

    In the present study, cold spraying technique was used to fabricate a metal matrix composite (MMC) that consists of Ni matrix and 20 vol.% Ni3Al particles at two different particle sizes as reinforcement. This study intends to investigate the effect of reinforcement particle size on microstructural and mechanical properties of cold sprayed MMCs. Two different Ni3Al powders with nominal particle size of -45 to +5 and +45 to 100 μm were used as reinforcement in this study. Cold sprayed Ni-Ni3Al samples were subjected to the microstructural observation and characterization prior to any mechanical testing. Then, samples were tested using nano-indentation, Knoop hardness, Vickers hardness, and Resonance frequency to evaluate their mechanical properties. No significant changes were observed in microstructural characteristics due to different particle sizes. The results obtained from a variety of mechanical testings indicated that the increasing reinforcement particle size resulted in the slight reduction of mechanical properties such as elastic modulus and hardness in cold sprayed MMCs. The mechanical interlock between deposited particles defines the bonding strength in cold sprayed samples. Small size particles have a higher velocity and impact resulting in stronger interlock between deformed particles.

  15. Total allowable concentrations of monomeric inorganic aluminum and hydrated aluminum silicates in drinking water.

    PubMed

    Willhite, Calvin C; Ball, Gwendolyn L; McLellan, Clifton J

    2012-05-01

    Maximum contaminant levels are used to control potential health hazards posed by chemicals in drinking water, but no primary national or international limits for aluminum (Al) have been adopted. Given the differences in toxicological profiles, the present evaluation derives total allowable concentrations for certain water-soluble inorganic Al compounds (including chloride, hydroxide, oxide, phosphate and sulfate) and for the hydrated Al silicates (including attapulgite, bentonite/montmorillonite, illite, kaolinite) in drinking water. The chemistry, toxicology and clinical experience with Al materials are extensive and depend upon the particular physical and chemical form. In general, the water solubility of the monomeric Al materials depends on pH and their water solubility and gastrointestinal bioavailability are much greater than that of the hydrated Al silicates. Other than Al-containing antacids and buffered aspirin, food is the primary source of Al exposure for most healthy people. Systemic uptake of Al after ingestion of the monomeric salts is somewhat greater from drinking water (0.28%) than from food (0.1%). Once absorbed, Al accumulates in bone, brain, liver and kidney, with bone as the major site for Al deposition in humans. Oral Al hydroxide is used routinely to bind phosphate salts in the gut to control hyperphosphatemia in people with compromised renal function. Signs of chronic Al toxicity in the musculoskeletal system include a vitamin D-resistant osteomalacia (deranged membranous bone formation characterized by accumulation of the osteoid matrix and reduced mineralization, reduced numbers of osteoblasts and osteoclasts, decreased lamellar and osteoid bands with elevated Al concentrations) presenting as bone pain and proximal myopathy. Aluminum-induced bone disease can progress to stress fractures of the ribs, femur, vertebrae, humerus and metatarsals. Serum Al ≥100 µg/L has a 75-88% positive predictive value for Al bone disease. Chronic Al

  16. Data Concentrator

    NASA Technical Reports Server (NTRS)

    Willett, Mike

    2015-01-01

    Orbital Research, Inc., developed, built, and tested three high-temperature components for use in the design of a data concentrator module in distributed turbine engine control. The concentrator receives analog and digital signals related to turbine engine control and communicates with a full authority digital engine control (FADEC) or high-level command processor. This data concentrator follows the Distributed Engine Controls Working Group (DECWG) roadmap for turbine engine distributed controls communication development that operates at temperatures at least up to 225 C. In Phase I, Orbital Research developed detailed specifications for each component needed for the system and defined the total system specifications. This entailed a combination of system design, compiling existing component specifications, laboratory testing, and simulation. The results showed the feasibility of the data concentrator. Phase II of this project focused on three key objectives. The first objective was to update the data concentrator design modifications from DECWG and prime contractors. Secondly, the project defined requirements for the three new high-temperature, application-specific integrated circuits (ASICs): one-time programmable (OTP), transient voltage suppression (TVS), and 3.3V. Finally, the project validated each design by testing over temperature and under load.

  17. AL Amyloidosis

    PubMed Central

    2012-01-01

    Definition of the disease AL amyloidosis results from extra-cellular deposition of fibril-forming monoclonal immunoglobulin (Ig) light chains (LC) (most commonly of lambda isotype) usually secreted by a small plasma cell clone. Most patients have evidence of isolated monoclonal gammopathy or smoldering myeloma, and the occurrence of AL amyloidosis in patients with symptomatic multiple myeloma or other B-cell lymphoproliferative disorders is unusual. The key event in the development of AL amyloidosis is the change in the secondary or tertiary structure of an abnormal monoclonal LC, which results in instable conformation. This conformational change is responsible for abnormal folding of the LC, rich in β leaves, which assemble into monomers that stack together to form amyloid fibrils. Epidemiology AL amyloidosis is the most common type of systemic amyloidois in developed countries with an estimated incidence of 9 cases/million inhabitant/year. The average age of diagnosed patients is 65 years and less than 10% of patients are under 50. Clinical description The clinical presentation is protean, because of the wide number of tissues or organs that may be affected. The most common presenting symptoms are asthenia and dyspnoea, which are poorly specific and may account for delayed diagnosis. Renal manifestations are the most frequent, affecting two thirds of patients at presentation. They are characterized by heavy proteinuria, with nephrotic syndrome and impaired renal function in half of the patients. Heart involvement, which is present at diagnosis in more than 50% of patients, leading to restrictive cardiopathy, is the most serious complication and engages prognosis. Diagnostic methods The diagnosis relies on pathological examination of an involved site showing Congo red-positive amyloid deposits, with typical apple-green birefringence under polarized light, that stain positive with an anti-LC antibody by immunohistochemistry and/or immunofluorescence. Due to the

  18. Profile video

    NASA Astrophysics Data System (ADS)

    Voglewede, Paul E.; Zampieron, Jeffrey

    2009-05-01

    For unattended persistent surveillance there is a need for a system which provides the following information: target classification, target quantity estimate, cargo presence and characterization, direction of travel, and action. Over highly bandwidth restricted links, such as Iridium, SATCOM or HF, the data rates of common techniques are too high, even after aggressive compression, to deliver the required intelligence in a timely, low power manner. We propose the following solution to this data rate problem: Profile Video. Profile video is a new technique which provides all of the required information in a very low data-rate package.

  19. Effect of adsorbed and substituted Al on Fe(II)-induced mineralization pathways of ferrihydrite

    NASA Astrophysics Data System (ADS)

    Hansel, C. M.; Learman, D. R.; Lentini, C. J.; Ekstrom, E. B.

    2011-08-01

    The poorly crystalline Fe(III) hydroxide ferrihydrite is considered one of the most important sinks for (in)organic contaminants and nutrients within soils, sediments, and waters. The ripening of ferrihydrite to more stable and hence less reactive phases such as goethite is catalyzed by surface reaction with aqueous Fe(II). While ferrihydrite within most natural environments contains high concentrations of adsorbed or co-precipitated cations (particularly Al), little is known regarding the impact of these cations on Fe(II)-induced transformation of ferrihydrite to secondary phases. Accordingly, we explored the extent, rates, and pathways of Fe(II)-induced secondary mineralization of Al-ferrihydrites by reacting aqueous Fe(II) (0.2 and 2.0 mM) with 2-line ferrihydrite containing a range of Al levels substituted within (6-24 mol% Al) or adsorbed on the surface (0.1-27% Γmax). Here, we show that regardless of the Fe(II) concentration, Al substituted within or adsorbed on ferrihydrite results in diminished secondary mineralization and preservation of ferrihydrite. In contrast to pure ferrihydrite, the concentration of Fe(II) may not in fact influence the mineralization products of Al-compromised ferrihydrites. Furthermore, the secondary mineral profiles upon Fe(II) reaction with ferrihydrite are not only a function of Al concentration but also the mode of Al incorporation. While Al substitution impedes lepidocrocite formation and magnetite nucleation, Al adsorption completely inhibits goethite formation and appears to have a lesser impact on magnetite nucleation. When normalized to total Al content associated with ferrihydrite, Al adsorption results in greater degree of ferrihydrite preservation relative to Al substitution. These findings provide insight into mechanisms that may be responsible for ferrihydrite preservation and low levels of secondary magnetite typically found in sedimentary environments. Considering the preponderance of cation substitution within and

  20. 10Be depth profile dating in the Swiss Midlands: deposition ages versus erosion

    NASA Astrophysics Data System (ADS)

    Wüthrich, Lorenz; Zech, Roland; Haghipour, Negar; Terrizzano, Carla; Christl, Marcus; Gnägi, Christian; Veit, Heinz; Ivy-Ochs, Susan

    2015-04-01

    During the Pleistocene, glaciers advanced repeatedly from the Alps into the Swiss Midlands. The exact extents and timing are still under debate, even for the last glacial advances. Decalcification depths, for example, increase from west to east in the western Swiss Midlands and have been interpreted to indicate that the Rhone glacier may have been less extensive during the global Last Glacial Maximum (LGM) at 20 ka than assumed so far [1]. In an attempt to provide more quantitative age control, we applied 10Be depth profile dating [2] on till at five locations in the western part of Switzerland. Two of them lie outside the assumed LGM extent of the Rhone glacier (Niederbuchsiten, St.Urban), two inside the extent of the LGM Rhone glacier (Steinhof, Deisswil) and one profile was taken from the Berne stade (LGM) of the Aare glacier [3]. All surface concentrations are relatively low and indicate massive erosion. Without constrains for age and erosion, depth profile dating yields ages between roughly 15 ka up to more than 1 Ma for the profiles in St. Urban, Niederbuchsiten and Deisswil whereas the profiles in Steinhof and Bern yields only last glacial ages. The wide range of possible exposure ages illustrates, that independent estimates for erosion would be needed to precisely determine the deposition ages of the investigated tills. However, at this point, we interpret the best model fits to our depth profile concentrations as tentative verification of the assumed LGM extent [3]. The spatial patterns of decalcification depths and soil development in the Swiss Midlands deserves further evaluation. [1] Bitterli et al. (2011) Geologischer Atlas der Schweiz, Blatt 1108, Swisstopo [2] Hidy et al. (2010) Geochem. Geophys. Geosyst. 11, doi:10.1029/2010GC003084 . [3] Bini et al. (2009) Switzerland during the Last Glacial Maximum, Swisstopo

  1. Si diffusion and intermixing in AlGaAs/GaAs structures using buried impurity sources

    SciTech Connect

    Beernink, K.J.; Thornton, R.L.; Anderson, G.B.; Emanuel, M.A.

    1995-05-08

    Si diffusion and impurity-induced layer intermixing from a buried impurity source have been studied by transmission electron microscopy and secondary ion mass spectroscopy of isolated, Si-doped GaAs layers in an undoped Al{sub 0.4}Ga{sub 0.6}As/GaAs superlattice and by photoluminescence measurements on Si-doped GaAs quantum wells with undoped Al{sub 0.4}Ga{sub 0.6}As barriers. In annealed samples, the Si profile suggests a Si diffusion process involving multiply ionized column III vacancies. The width of the resulting Si profile and the spatial extent and completeness of intermixing strongly depend on the initial Si concentration in the doped layer.

  2. Direct measurement of surface carbon concentrations for lunar soil breccias

    NASA Technical Reports Server (NTRS)

    Filleux, C.; Spear, R. H.; Tombrello, T. A.; Burnett, D. S.

    1978-01-01

    A nuclear reaction depth profiling technique previously described by Filleux et al. (1977) has been used to measure the depth distribution of C on grain surfaces for Apollo 11, 15, 16 and 17 soil breccias. The surface C concentration of all samples studied lies between 2 and 8 times 10 to the 15th atoms per sq cm, showing no correlation with the volume C, which varies over an order of magnitude. If the observed variation represents the presence of unexposed grains on the surfaces studied, these results indicate a steady state surface C concentration of 5 to 10 times 10 to the 15th atoms per sq cm, accumulated over a time scale short compared with that required for the formation of volume-related C and with the mean lifetime of grains at the lunar surface. About one-third to one-half of the total C in lunar soil seems to be surface-correlated.

  3. Elemental profiles and signatures of fugitive dusts from Chinese deserts.

    PubMed

    Zhang, Rong; Cao, Junji; Tang, Yanrong; Arimoto, Richard; Shen, Zhenxing; Wu, Feng; Han, Yongming; Wang, Gehui; Zhang, Jiaquan; Li, Guohui

    2014-02-15

    Elemental profiles were determined for size-separated fugitive dust particles produced from Chinese desert and gobi soils. Seventeen surface soil samples from six Chinese deserts were collected, composited, resuspended, and sampled through TSP, PM10, and PM2.5 inlets onto Teflon® filters, which were analyzed for twenty-six elements. Two major dust sources could be distinguished based on differences in crustal and enriched elements-the northwestern (NW) region (Taklimakan Desert, Xinjiang Gobi, and Anxinan Gobi) and northern (N) region (Ulan Buh Desert, Central Inner Mongolia Desert, and Erenhot Gobi). The N sources showed lower concentrations of mineral elements (Fe, K, Na, Ti, Mn, Cr, and Rb in PM10, and Fe, K, Ti, Mn, Co, and V in PM2.5) and higher levels of contaminants (S, Zn, Mo, Cu, Cr, Pb, Cd, and As) than the NW ones, especially in PM2.5. Enrichment factors for Cu, Cr, Zn, Pb, As, Mo, and Cd calculated relative to the upper continental crust showed enrichments of one to two orders-of-magnitude, and they were much higher for N sources than NW ones, implying stronger anthropogenic impacts in north China. Aerosol elemental concentrations during dust events at Horqin, Beijing, and Xi'an matched the mass percentages of mineral elements from their presumptive sources better than the alternative ones, validating the differences between the NW and N sources. Additionally, Na/S, Mg/S, Fe/Al, K/Al, Si/Fe, and Na/Al ratios were suggested to differentiate the two dust source regions. The elemental ratios of Ca/Al, K/Al, Fe/Al, and Ti/Fe in the source regions matched those in aerosols collected downwind, and they can be considered as possible source indicators. PMID:24361747

  4. Medical application of 26Al

    NASA Astrophysics Data System (ADS)

    Steinhausen, C.; Gerisch, P.; Heisinger, B.; Hohl, Ch.; Kislinger, G.; Korschinek, G.; Niedermayer, M.; Nolte, E.; Dumitru, M.; Alvarez-Brückmann, M.; Schneider, M.; Ittel, T. H.

    1996-06-01

    Accelerator mass spectrometry (AMS) measurements with 26Al as tracer were performed in order to study the aluminium metabolism and anomalies in the human body and in rats. In particular, the differences between healthy volunteers and patients with renal failure were investigated. The obtained data points of 26Al in blood and urine were described by an open compartment model with three peripheral compartments. It was found that the minimum of peripheral compartments needed to describe 26Al concentrations in blood and urine over a time period of three years is at least three.

  5. CEMS and DCEMS investigations of Al-implanted iron

    NASA Astrophysics Data System (ADS)

    Reuther, H.; Nikolov, O.; Kruijer, S.; Brand, R. A.; Keune, W.; Liljequist, D.; Weber, S.; Scherrer, S.

    1994-12-01

    α-Fe surfaces were implanted with a nominal dose of 5×1017 Al ions/cm2 at 50 keV and a current density of about 3.7 μA/cm2. Samples of different shapes and thicknesses have been used in order to test the influence of heat flow from specimen to target holder during implantation. Integral and energy differential (“depth-selective”)57Fe conversion electron Mössbauer spectroscopy (CEMS and DCEMS) were employed. The spectra indicated a magnetic phase characterised by a broad hyperfine field distribution P(B hf), a non-magnetic phase, and α-Fe. The relative intensity of the non-magnetic phase was enhanced if the thermal contact during implantation became worse. An energy dependence of DCEM spectra in the L-electron range was observed. Model calculations using L-electron weight functions and experimental concentration profiles obtained by secondary neutral mass spectroscopy (SNMS) yielded fair agreement between calculated and experimental phase signals. The results demonstrate that the non-magnetic Fe-Al alloy phase with high Al concentration is located closer to the surface than the magnetic alloy phase, which extends to much larger depth than expected.

  6. Patent profiles

    SciTech Connect

    Not Available

    1980-01-01

    This report presents profiles of US patents in the area of solar energy technology, and in the related areas of wind, geothermal and tide and wave energy. Each profile is divided into three parts. The first part identifies the area which is examined, lists the pertinent US Patent Classification(s), and graphically illustrates patent activity across a designated 10-year span. The second part tabulates the data upon which the graphs of the first part were based, provides a list of assignees for the period 1969 to 1978 both by the number of patents and alphabetically, and presents on alphabetical listing of inventors of unassigned patents. The third part updates the preceding material for the period January-October 1979. (SPH)

  7. Formation Mechanisms of Alloying Element Nitrides in Recrystallized and Deformed Ferritic Fe-Cr-Al Alloy

    NASA Astrophysics Data System (ADS)

    Akhlaghi, Maryam; Meka, Sai Ramudu; Jägle, Eric A.; Kurz, Silke J. B.; Bischoff, Ewald; Mittemeijer, Eric J.

    2016-07-01

    The effect of the initial microstructure (recrystallized or cold-rolled) on the nitride precipitation process upon gaseous nitriding of ternary Fe-4.3 at. pct Cr-8.1 at. pct Al alloy was investigated at 723 K (450 °C) employing X-ray diffraction (XRD) analyses, transmission electron microscopy (TEM), atom probe tomography (APT), and electron probe microanalysis (EPMA). In recrystallized Fe-Cr-Al specimens, one type of nitride develops: ternary, cubic, NaCl-type mixed Cr1-x Al x N. In cold-rolled Fe-Cr-Al specimens, precipitation of two types of nitrides occurs: ternary, cubic, NaCl-type mixed Cr1-x Al x N and binary, cubic, NaCl-type AlN. By theoretical analysis, it was shown that for the recrystallized specimens an energy barrier for the nucleation of mixed Cr1-x Al x N exists, whereas in the cold-rolled specimens no such energy barriers for the development of mixed Cr1-x Al x N and of binary, cubic AlN occur. The additional development of the cubic AlN in the cold-rolled microstructure could be ascribed to the preferred heterogeneous nucleation of cubic AlN on dislocations. The nitrogen concentration-depth profile of the cold-rolled specimen shows a stepped nature upon prolonged nitriding as a consequence of instantaneous nucleation of nitride upon arrival of nitrogen and nitride growth rate-limited by nitrogen transport through the thickening nitrided zone.

  8. Formation Mechanisms of Alloying Element Nitrides in Recrystallized and Deformed Ferritic Fe-Cr-Al Alloy

    NASA Astrophysics Data System (ADS)

    Akhlaghi, Maryam; Meka, Sai Ramudu; Jägle, Eric A.; Kurz, Silke J. B.; Bischoff, Ewald; Mittemeijer, Eric J.

    2016-09-01

    The effect of the initial microstructure (recrystallized or cold-rolled) on the nitride precipitation process upon gaseous nitriding of ternary Fe-4.3 at. pct Cr-8.1 at. pct Al alloy was investigated at 723 K (450 °C) employing X-ray diffraction (XRD) analyses, transmission electron microscopy (TEM), atom probe tomography (APT), and electron probe microanalysis (EPMA). In recrystallized Fe-Cr-Al specimens, one type of nitride develops: ternary, cubic, NaCl-type mixed Cr1- x Al x N. In cold-rolled Fe-Cr-Al specimens, precipitation of two types of nitrides occurs: ternary, cubic, NaCl-type mixed Cr1- x Al x N and binary, cubic, NaCl-type AlN. By theoretical analysis, it was shown that for the recrystallized specimens an energy barrier for the nucleation of mixed Cr1- x Al x N exists, whereas in the cold-rolled specimens no such energy barriers for the development of mixed Cr1- x Al x N and of binary, cubic AlN occur. The additional development of the cubic AlN in the cold-rolled microstructure could be ascribed to the preferred heterogeneous nucleation of cubic AlN on dislocations. The nitrogen concentration-depth profile of the cold-rolled specimen shows a stepped nature upon prolonged nitriding as a consequence of instantaneous nucleation of nitride upon arrival of nitrogen and nitride growth rate-limited by nitrogen transport through the thickening nitrided zone.

  9. Stoichiometry dependence of potential screening at La ( 1 - δ ) Al ( 1 + δ ) O 3 / SrTiO 3 interfaces

    DOE PAGESBeta

    Weiland, Conan; Sterbinsky, George E.; Rumaiz, Abdul K.; Hellberg, C. Stephen; Woicik, Joseph C.; Zhu, Shaobo; Schlom, Darrell G.

    2015-04-03

    Hard x-ray photoelectron spectroscopy (HAXPES) and variable kinetic energy x-ray photoelectron spectroscopy (VKE-XPS) analyses have been performed on ten-unit-cell-thick La(1-δ)Al(1+δ)O₃ films, with La:Al ratios of 1.1, 1.0, and 0.9, deposited on SrTiO₃. Only Al-rich films are known to have a conductive interface. VKE-XPS, coupled with maximum entropy analysis, shows significant differences in the compositional depth profile among the Al-rich, La-rich, and stoichiometric films: significant La enrichment at the interface is observed in the La-rich and stoichiometric films, while the Al-rich film shows little to no intermixing. Additionally, the La-rich and stoichiometric films show a high concentration of Al at themore » surface, which is not observed in the Al-rich film. HAXPES valence band (VB) analysis shows a broadening of the VB for the Al-rich sample relative to the stoichiometric and La-rich samples. This broadening is consistent with an electric field across the Al-rich film. These results are consistent with a defect-driven electronic reconstruction.« less

  10. Solar concentrator

    SciTech Connect

    Smyth, J.S.

    1982-06-08

    A solar concentrator having an open framework formed as a geodesic dome. A rotatable support axle extends substantially diametrically across the dome and has the opposite ends thereof supported on the framework. The support axle defines a first rotational axis which is oriented to extend substantially parallel with the earth's north-south axis. A support post is hingedly mounted on the support shaft substantially at the midpoint thereof for permitting angular displacement of the support post relative to the support shaft about a second rotational axis which is perpendicular to the first axis. A dishshaped reflector assembly is positioned within the interior of the framework and fixedly secured to the support post. First and second drives effect angular displacement of the reflector assembly about the first and second axes, respectively, to permit tracking of the solar position.

  11. MPI Profiling

    SciTech Connect

    Han, D K; Jones, T R

    2005-02-11

    The Message Passing Interface (MPI) is the de facto message-passing standard for massively parallel programs. It is often the case that application performance is a crucial factor, especially for solving grand challenge problems. While there have been many studies on the scalability of applications, there have not been many focusing on the specific types of MPI calls being made and their impact on application performance. Using a profiling tool called mpiP, a large spectrum of parallel scientific applications were surveyed and their performance results analyzed.

  12. Use of a Cumulative Exposure Index to Estimate the Impact of Tap Water Lead Concentration on Blood Lead Levels in 1- to 5-Year-Old Children (Montréal, Canada)

    PubMed Central

    Ngueta, Gerard; Abdous, Belkacem; Tardif, Robert; St-Laurent, Julie; Levallois, Patrick

    2015-01-01

    Background Drinking water is recognized as a source of lead (Pb) exposure. However, questions remain about the impact of chronic exposure to lead-contaminated water on internal dose. Objective Our goal was to estimate the relation between a cumulative water Pb exposure index (CWLEI) and blood Pb levels (BPb) in children 1–5 years of ages. Methods Between 10 September 2009 and 27 March 2010, individual characteristics and water consumption data were obtained from 298 children. Venous blood samples were collected (one per child) and a total of five 1-L samples of water per home were drawn from the kitchen tap. A second round of water collection was performed between 22 June 2011 and 6 September 2011 on a subsample of houses. Pb analyses used inductively coupled plasma mass spectroscopy. Multiple linear regressions were used to estimate the association between CWLEI and BPb. Results Each 1-unit increase in CWLEI multiplies the expected value of BPb by 1.10 (95% CI: 1.06, 1.15) after adjustment for confounders. Mean BPb was significantly higher in children in the upper third and fourth quartiles of CWLEI (0.7–1.9 and ≥ 1.9 μg/kg of body weight) compared with the first (< 0.2 μg/kg) after adjusting for confounders (19%; 95% CI: 0, 42% and 39%; 95% CI: 15, 67%, respectively). The trends analysis yielded a p-value < 0.0001 after adjusting for confounders suggesting a dose–response relationship between percentiles of CWLEI and BPb. Conclusions In children 1–5 years of age, BPb was significantly associated with water lead concentration with an increase starting at a cumulative lead exposure of ≥ 0.7 μg Pb/kg of body weight. In this age group, an increase of 1 μg/L in water lead would result in an increase of 35% of BPb after 150 days of exposure. Citation Ngueta G, Abdous B, Tardif R, St-Laurent J, Levallois P. 2016. Use of a cumulative exposure index to estimate the impact of tap water lead concentration on blood lead levels in 1- to 5-year-old children

  13. Fasting is not routinely required for determination of a lipid profile: clinical and laboratory implications including flagging at desirable concentration cut-points—a joint consensus statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine

    PubMed Central

    Nordestgaard, Børge G.; Langsted, Anne; Mora, Samia; Kolovou, Genovefa; Baum, Hannsjörg; Bruckert, Eric; Watts, Gerald F.; Sypniewska, Grazyna; Wiklund, Olov; Borén, Jan; Chapman, M. John; Cobbaert, Christa; Descamps, Olivier S.; von Eckardstein, Arnold; Kamstrup, Pia R.; Pulkki, Kari; Kronenberg, Florian; Remaley, Alan T.; Rifai, Nader; Ros, Emilio; Langlois, Michel

    2016-01-01

    Aims To critically evaluate the clinical implications of the use of non-fasting rather than fasting lipid profiles and to provide guidance for the laboratory reporting of abnormal non-fasting or fasting lipid profiles. Methods and results Extensive observational data, in which random non-fasting lipid profiles have been compared with those determined under fasting conditions, indicate that the maximal mean changes at 1–6 h after habitual meals are not clinically significant [+0.3 mmol/L (26 mg/dL) for triglycerides; −0.2 mmol/L (8 mg/dL) for total cholesterol; −0.2 mmol/L (8 mg/dL) for LDL cholesterol; +0.2 mmol/L (8 mg/dL) for calculated remnant cholesterol; −0.2 mmol/L (8 mg/dL) for calculated non-HDL cholesterol]; concentrations of HDL cholesterol, apolipoprotein A1, apolipoprotein B, and lipoprotein(a) are not affected by fasting/non-fasting status. In addition, non-fasting and fasting concentrations vary similarly over time and are comparable in the prediction of cardiovascular disease. To improve patient compliance with lipid testing, we therefore recommend the routine use of non-fasting lipid profiles, while fasting sampling may be considered when non-fasting triglycerides >5 mmol/L (440 mg/dL). For non-fasting samples, laboratory reports should flag abnormal concentrations as triglycerides ≥2 mmol/L (175 mg/dL), total cholesterol ≥5 mmol/L (190 mg/dL), LDL cholesterol ≥3 mmol/L (115 mg/dL), calculated remnant cholesterol ≥0.9 mmol/L (35 mg/dL), calculated non-HDL cholesterol ≥3.9 mmol/L (150 mg/dL), HDL cholesterol ≤1 mmol/L (40 mg/dL), apolipoprotein A1 ≤1.25 g/L (125 mg/dL), apolipoprotein B ≥1.0 g/L (100 mg/dL), and lipoprotein(a) ≥50 mg/dL (80th percentile); for fasting samples, abnormal concentrations correspond to triglycerides ≥1.7 mmol/L (150 mg/dL). Life-threatening concentrations require separate referral when triglycerides >10 mmol/L (880 mg/dL) for the risk of pancreatitis, LDL cholesterol >13 mmol/L (500 mg/dL) for

  14. A perspective on re-evaluating digoxin's role in the current management of patients with chronic systolic heart failure: targeting serum concentration to reduce hospitalization and improve safety profile.

    PubMed

    Adams, Kirkwood F; Ghali, Jalal K; Herbert Patterson, J; Stough, Wendy Gattis; Butler, Javed; Bauman, Jerry L; Ventura, Hector O; Sabbah, Hani; Mackowiak, John I; van Veldhuisen, Dirk J

    2014-05-01

    Digoxin improves exercise tolerance and reduces hospitalizations in patients with systolic heart failure, but its use has declined progressively for the past two decades. The Digitalis Investigation Group trial showed that digoxin reduced hospitalizations but had a neutral effect on total mortality. There was evidence that mortality caused by worsening heart failure was less, but there was also a signal suggesting an increase in other cardiac (presumed arrhythmic) death. Use of digoxin has declined substantially and recent guideline recommendations have significantly de-emphasized the importance of this drug in the management of heart failure. Two developments suggest that re-evaluation of the contemporary role of digoxin in the management of heart failure with reduced ejection fraction is warranted. First, heart failure remains progressive, characterized by chronic debility, exercise intolerance, and frequent and costly hospitalizations, despite evidence-based drug and device therapies that prolong survival. Health economics have made reducing hospitalizations in patients with heart failure a major priority. Second, a strong association has emerged between serum concentration and the safety and efficacy of digoxin, which indicates a change in our approach to dosing this agent is needed. Experimental and clinical results suggest that optimizing therapeutic benefit and avoiding harm means dosing to achieve low serum digoxin concentrations (0.5-0.9 ng/mL). Digoxin is an inexpensive agent and the totality of evidence indicates that it reduces hospitalizations and improves symptoms safely when dosed to achieve low serum concentrations. These findings suggest digoxin should have a more prominent therapeutic role in patients with heart failure and reduced ejection fraction. PMID:24574198

  15. Nano-scale simultaneous observation of Li-concentration profile and Ti-, O electronic structure changes in an all-solid-state Li-ion battery by spatially-resolved electron energy-loss spectroscopy

    NASA Astrophysics Data System (ADS)

    Yamamoto, Kazuo; Yoshida, Ryuji; Sato, Takeshi; Matsumoto, Hiroaki; Kurobe, Hisanori; Hamanaka, Tadashi; Kato, Takehisa; Iriyama, Yasutoshi; Hirayama, Tsukasa

    2014-11-01

    All-solid-state Li-ion batteries having incombustible solid electrolytes are expected to be promising candidates for safe next-generation energy storage devices that have a long lifetime and high energy density. However, it is essential to address the large resistance of Li-ion transfer at the electrode/solid-electrolyte interfaces. A new concept electrode that is formed in situ from the Li2O-Al2O3-TiO2-P2O5-based glass-ceramic solid electrolytes with Si and Ge doping (LASGTP) produces atomic scale connection at the interfaces, which provides extremely low interfacial resistance. However, the formation mechanism and the reason for the low resistance are still unclear. Here we applied spatially-resolved electron energy-loss spectroscopy in a transmission electron microscope mode (SR-TEM-EELS) to visualize the nanometer-scale Li distribution and its effects on the electronic structures of other important elements (Ti and O). Local electron diffraction showed that the in situ formed electrode was an amorphous phase caused by the Li insertion. Picometer-scale expansion of O-O distance due to the Li insertion was also visualized in the electrode. These electronic and crystal changes and gradual Li distribution contribute to the low resistance and stable battery cycles.

  16. Low-temperature laser assisted CBE-growth of AlGaAs

    NASA Astrophysics Data System (ADS)

    Jothilingam, R.; Farrell, T.; Joyce, T. B.; Goodhew, P. J.

    1998-06-01

    We report preliminary studies of low-temperature (335-400°C) chemical beam epitaxial (CBE) growth of Al xGa 1- xAs on GaAs(0 0 1) using triethylgallium (TEG), trimethylaminealane (TMAA) and thermally precracked Arsine (AsH 3) as precursors. We also report results of Ar + laser assisted chemical beam epitaxial growth over the same temperature range. The growth rate for both assisted and unassisted growth as a function of substrate temperature, laser power and precursor beam pressures was determined using laser reflectometry in which the Ar + laser was also used as the probe. In the nonlaser assisted growth Al incorporation is observed to be significantly higher than would be expected at the normal growth temperature of 500°C. With laser assistance the Al concentration, while higher than that at normal growth temperatures, is less than that without laser assistance and the growth rate is higher. These observations, which extended Abernathy's early results to higher nominal Al concentration, are discussed in terms of the relative enhancement of the decomposition of TEG and the alane during laser assistance. Using literature values of the refractive index of AlGaAs alloys at the growth temperature, laser reflectometry was used to monitor both composition and growth rate over a range of growth temperatures. Reflectometry data were compared with the results of Auger Electron Microscopy (AES) and Dektak stylus profiling.

  17. Profiling users in the UNIX os environment

    SciTech Connect

    Dao, V N P; Vemuri, R; Templeton, S J

    2000-09-29

    This paper presents results obtained by using a method of profiling a user based on the login host, the login time, the command set, and the command set execution time of the profiled user. It is assumed that the user is logging onto a UNIX host on a computer network. The paper concentrates on two areas: short-term and long-term profiling. In short-term profiling the focus is on profiling the user at a given session where user characteristics do not change much. In long-term profiling, the duration of observation is over a much longer period of time. The latter is more challenging because of a phenomenon called concept or profile drift. Profile drift occurs when a user logs onto a host for an extended period of time (over several sessions).

  18. Mechanisms of Chromate, Selenate, and Sulfate Adsorption on Al-Substituted Ferrihydrite: Implications for Ferrihydrite Surface Structure and Reactivity.

    PubMed

    Johnston, Chad P; Chrysochoou, Maria

    2016-04-01

    Ferrihydrite is a nanocrystalline Fe (hydr)oxide and important sink for environmental contaminants. Although Fe (hydr)oxides are rarely pure in natural systems, little is known about the effects of structural impurities such as Al on the surface properties and reactivity of ferrihydrite. In this study, we characterized the adsorption mechanisms of chromate, selenate, and sulfate on Al-substituted ferrihydrite (0, 6, 12, 18, and 24 mol % Al) using in situ attenuated total reflection Fourier transform infrared spectroscopy. Spectral data sets recorded as a function of pH were processed using a multivariate curve resolution technique to identify which types of surface species form and to generate their concentration profiles as a function of pH and Al content. Results show a significant increase in relative fraction of outer-sphere complexes for all three oxyanions with increasing Al substitution. In addition, the effect of Al substitution is found to be mechanism-specific in the case of chromate, with bidentate complexes disproportionately suppressed over monodentate complexes at higher Al contents. Overall, our findings have important implications for the fate of chromate, selenate, and sulfate in subsurface environments and offer new insight into the surface reactivity of Al-ferrihydrite. PMID:26900715

  19. Field methods for measuring concentrated flow erosion

    NASA Astrophysics Data System (ADS)

    Castillo, C.; Pérez, R.; James, M. R.; Quinton, J. N.; Taguas, E. V.; Gómez, J. A.

    2012-04-01

    Many studies have stressed the importance of gully erosion in the overall soil loss and sediment yield of agricultural catchments, for instance in recent years (Vandaele and Poesen, 1995; De Santisteban et al., 2006; Wu el al, 2008). Several techniques have been used for determining gully erosion in field studies. The conventional techniques involved the use of different devices (i.e. ruler, pole, tape, micro-topographic profilers, total station) to calculate rill and gully volumes through the determination of cross sectional areas and length of reaches (Casalí et al, 1999; Hessel and van Asch, 2003). Optical devices (i.e. laser profilemeters) have also been designed for the purpose of rapid and detailed assessment of cross sectional areas in gully networks (Giménez et al., 2009). These conventional 2d methods provide a simple and un-expensive approach for erosion evaluation, but are time consuming to carry out if a good accuracy is required. On the other hand, remote sensing techniques are being increasingly applied to gully erosion investigation such as aerial photography used for big-scale, long-term, investigations (e.g. Martínez-Casasnovas et al., 2004; Ionita, 2006), airborne and terrestrial LiDAR datasets for gully volume evaluation (James et al., 2007; Evans and Lindsay, 2010) and recently, major advances in 3D photo-reconstruction techniques (Welty et al. 2010, James et al., 2011). Despite its interest, few studies simultaneously compare the accuracies of the range of conventional and remote sensing techniques used, or define the most suitable method for a particular scale, given and time and cost constraints. That was the reason behind the International Workshop Innovations in the evaluation and measurement of rill and gully erosion, held in Cordoba in May 2011 and from which derive part of the materials presented in this abstract. The main aim of this work was to compare the accuracy and time requirements of traditional (2D) and recently developed

  20. Magnetism of Al-Mn quasicrystals

    SciTech Connect

    Liu, F.; Khanna, S.N.; Magaud, L.; Jena, P. ); de Coulon, V.; Reuse, F. ); Jaswal, S.S.; He, X. ); Cyrot-Lackman, F. )

    1993-07-01

    The effect of symmetry and concentration of Mn on the magnetism of Al-Mn quasicrystals has been investigated through self-consistent density-functional calculations using molecular clusters and supercell band-structure schemes. A single Mn atom surrounded by 54 Al atoms in an icosahedral or a cuboctahedral structure is found to be nonmagnetic. However, as the Mn concentration is increased, moments develop on Mn sites whose magnitude and coupling depend on their location.

  1. Evaluation of the tropospheric aerosol number concentrations simulated by two versions of the global model ECHAM5-HAM

    NASA Astrophysics Data System (ADS)

    Zhang, K.; Kazil, J.; Feichter, J.

    2009-04-01

    Since its first version developed by Stier et al. (2005), the global aerosol-climate model ECHAM5-HAM has gone through further development and updates. The changes in the model include (1) a new time integration scheme for the condensation of the sulfuric acid gas on existing particles, (2) a new aerosol nucleation scheme that takes into account the charged nucleation caused by cosmic rays, and (3) a parameterization scheme explicitly describing the conversion of aerosol particles to cloud nuclei. In this work, simulations performed with the old and new model versions are evaluated against some measurements reported in recent years. The focus is on the aerosol size distribution in the troposphere. Results show that modifications in the parameterizations have led to significant changes in the simulated aerosol concentrations. Vertical profiles of the total particle number concentration (diameter > 3nm) compiled by Clarke et al. (2002) suggest that, over the Pacific in the upper free troposphere, the tropics are associated with much higher concentrations than the mid-latitude regions. This feature is more reasonably reproduced by the new model version, mainly due to the improved results of the nucleation mode aerosols. In the lower levels (2-5 km above the Earth's surface), the number concentrations of the Aitken mode particles are overestimated compared to both the Pacific data given in Clarke et al. (2002) and the vertical profiles over Europe reported by Petzold et al. (2007). The physical and chemical processes that have led to these changes are identified by sensitivity tests. References: Clarke and Kapustin: A Pacific aerosol survey - part 1: a decade of data on production, transport, evolution and mixing in the troposphere, J. Atmos. Sci., 59, 363-382, 2002. Petzold et al.: Perturbation of the European free troposphere aerosol by North American forest fire plumes during the ICARTT-ITOP experiment in summer 2004, Atmos. Chem. Phys., 7, 5105-5127, 2007

  2. AlN/Fe/AlN nanostructures for magnetooptic magnetometry

    SciTech Connect

    Lišková-Jakubisová, E. Višňovský, Š.; Široký, P.; Hrabovský, D.; Pištora, J.

    2014-05-07

    AlN/Fe/AlN/Cu nanostructures with ultrathin Fe grown by sputtering on Si substrates are evaluated as probes for magnetooptical (MO) mapping of weak currents. They are considered for a laser wavelength of λ = 410 nm (3.02 eV) and operate at oblique light incidence angles, φ{sup (0)}, to enable detection of both in-plane and out-of-plane magnetization. Their performance is evaluated in terms of MO reflected wave electric field amplitudes. The maximal MO amplitudes in AlN/Fe/AlN/Cu are achieved by a proper choice of layer thicknesses. The nanostructures were characterized by MO polar Kerr effect at φ{sup (0)} ≈ 5° and longitudinal Kerr effect spectra (φ{sup (0)} = 45°) at photon energies between 1 and 5 eV. The nominal profiles were refined using a model-based analysis of the spectra. Closed form analytical expressions are provided, which are useful in the search for maximal MO amplitudes.

  3. High efficiency compound semiconductor concentrator photovoltaics

    NASA Technical Reports Server (NTRS)

    Borden, P.; Gregory, P.; Saxena, R.; Owen, R.; Moore, O.

    1980-01-01

    Special emphasis was given to the high yield pilot production of packaged AlGaAs/GaAs concentrator solar cells, using organometallic VPE for materials growth, the demonstration of a concentrator module using 12 of these cells which achieved 16.4 percent conversion efficiency at 50 C coolant inlet temperature, and the demonstration of a spectral splitting converter module that achieved in excess of 20 percent efficiency. This converter employed ten silicon and ten AlGaAs cells with a dichroic filter functioning as the beam splitter. A monolithic array of AlGaAs/GaAs solar cells is described.

  4. Estimation of background carrier concentration in fully depleted GaN films

    NASA Astrophysics Data System (ADS)

    Chandrasekar, Hareesh; Singh, Manikant; Raghavan, Srinivasan; Bhat, Navakanta

    2015-11-01

    Buffer leakage is an important parasitic loss mechanism in AlGaN/GaN high electron mobility transistors (HEMTs) and hence various methods are employed to grow semi-insulating buffer layers. Quantification of carrier concentration in such buffers using conventional capacitance based profiling techniques is challenging due to their fully depleted nature even at zero bias voltages. We provide a simple and effective model to extract carrier concentrations in fully depleted GaN films using capacitance-voltage (C-V) measurements. Extensive mercury probe C-V profiling has been performed on GaN films of differing thicknesses and doping levels in order to validate this model. Carrier concentrations as extracted from both the conventional C-V technique for partially depleted films having the same doping concentration, and Hall measurements show excellent agreement with those predicted by the proposed model thus establishing the utility of this technique. This model can be readily extended to estimate background carrier concentrations from the depletion region capacitances of HEMT structures and fully depleted films of any class of semiconductor materials.

  5. Methods for sperm concentration determination.

    PubMed

    Björndahl, Lars

    2013-01-01

    Proper assessment of the number of spermatozoa is essential not only as an initial step in every clinical infertility investigation [Björndahl et al (2010) A practical guide to basic laboratory andrology, 1st edn. Cambridge University Press, Cambridge] but also when attempting to establish the total sperm production in the testis [Amann (Hum Reprod 25:22-28, 2010); Amann (J Androl 30:626-641, 2009); Amann and Chapman (J Androl 30:642-649, 2009)]. Reliable methods combined with an understanding of the specific physiology involved as well as the main sources of errors related to the assessment of sperm concentration are critical for ensuring accurate concentration determination [Björndahl et al (2010) A practical guide to basic laboratory andrology, 1st edn. Cambridge University Press, Cambridge; World Health Organization (2010) WHO laboratory manual for the examination and processing of human semen. WHO, Geneva]. This chapter therefore focuses on these three aspects. PMID:22992898

  6. Atomistic Modeling of RuAl and (RuNi) Al Alloys

    NASA Technical Reports Server (NTRS)

    Gargano, Pablo; Mosca, Hugo; Bozzolo, Guillermo; Noebe, Ronald D.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    Atomistic modeling of RuAl and RuAlNi alloys, using the BFS (Bozzolo-Ferrante-Smith) method for alloys is performed. The lattice parameter and energy of formation of B2 RuAl as a function of stoichiometry and the lattice parameter of (Ru(sub 50-x)Ni(sub x)Al(sub 50)) alloys as a function of Ni concentration are computed. BFS based Monte Carlo simulations indicate that compositions close to Ru25Ni25Al50 are single phase with no obvious evidence of a miscibility gap and separation of the individual B2 phases.

  7. Al-doped ZnO nanocrystals

    NASA Astrophysics Data System (ADS)

    Kadam, Pratibha; Agashe, Chitra; Mahamuni, Shailaja

    2008-11-01

    Al3+-doped ZnO nanocrystals were differently obtained by wet chemical and an electrochemical route. An increase in forbidden gap due to change in crystal size and also due to Al3+ doping in ZnO is critically analyzed. The Moss-Burstein type shift in Al3+-doped ZnO nanocrystals provides an evidence of successful Al3+ doping in ZnO nanocrystals. The possibility of varying the carrier concentration in ZnO nanocrystals is the indirect implication of the present investigations.

  8. AlSb/InAs/AlSb quantum wells

    NASA Technical Reports Server (NTRS)

    Kroemer, Herbert

    1990-01-01

    Researchers studied the InAs/AlSb system recently, obtaining 12nm wide quantum wells with room temperature mobilities up to 28,000 cm(exp 2)/V center dot S and low-temperature mobilities up to 325,000 cm(exp 2)/V center dot S, both at high electron sheet concentrations in the 10(exp 12)/cm(exp 2) range (corresponding to volume concentrations in the 10(exp 18)/cm(exp 2) range). These wells were not intentionally doped; the combination of high carrier concentrations and high mobilities suggest that the electrons are due to not-intentional modulation doping by an unknown donor in the AlSb barriers, presumably a stoichiometric defect, like an antisite donor. Inasmuch as not intentionally doped bulk AlSb is semi-insulating, the donor must be a deep one, being ionized only by draining into the even deeper InAs quantum well. The excellent transport properties are confirmed by other observations, like excellent quantum Hall effect data, and the successful use of the quantum wells as superconductive weak links between Nb electrodes, with unprecendentedly high critical current densities. The system is promising for future field effect transistors (FETs), but many processing problems must first be solved. Although the researchers have achieved FETs, the results so far have not been competitive with GaAs FETs.

  9. Erbium-ion implantation into various crystallographic cuts of Al2O3

    NASA Astrophysics Data System (ADS)

    Nekvindova, P.; Mackova, A.; Malinsky, P.; Cajzl, J.; Svecova, B.; Oswald, J.; Wilhelm, R. A.

    2015-12-01

    This paper reports on the importance of crystallographic cuts with a different orientation on the luminescent properties and structural changes of Al2O3 implanted with Er+ ions at 190 keV and with a fluence of 1.0 × 1016 cm-2. Post-implantation annealing at 1000 °C in oxygen atmosphere was also done. The chemical compositions and erbium concentration-depth profiles of implanted layers were studied by Rutherford Backscattering Spectrometry (RBS) and compared to SRIM simulations. The same value of the maximum erbium concentration (up to 2 at.%) was observed at a depth of about 40 nm for all crystallographic cuts. The structural properties of the prepared layers were characterised by RBS/channelling. The relative amount of disordered atoms of 70-80% was observed in the prepared implanted layers and discussed for various cuts. It has been found that erbium is positioned randomly in the Al2O3 crystalline matrix, and no preferential positions appeared even after the annealing procedure. Erbium luminescence properties were measured in the wavelength range of 1440-1650 nm for all samples. As-implanted Al2O3 samples had a significant luminescence band at 1530 nm. The best luminescence was repeatedly observed in the <0 0 0 1> cut of Al2O3. The annealing procedure significantly improved the luminescent properties.

  10. Comparative study on interface and bulk charges in AlGaN/GaN metal-insulator-semiconductor heterostructures with Al2O3, AlN, and Al2O3/AlN laminated dielectrics

    NASA Astrophysics Data System (ADS)

    Zhu, Jie-Jie; Ma, Xiao-Hua; Chen, Wei-Wei; Hou, Bin; Xie, Yong; Hao, Yue

    2016-05-01

    In this paper, the interface and bulk charges in AlGaN/GaN metal-insulator-semiconductor (MIS) heterostructures with AlN, Al2O3, and Al2O3/AlN laminated dielectrics were studied. In situ plasma pretreatment resulted negligible interface trap states and voltage hysteresis. The fixed charge density at Al2O3/AlN (or Al2O3/barrier) interface was estimated to be 1.66 × 1013 cm-2 by using flat-band voltage shift, and the oxide bulk charge concentration was 2.86 × 1017 cm-3. The interface charge density at other interfaces were at the order of 1011 cm-2. Simulation results using the above charge density/concentration indicated that Al2O3/AlN interface fixed charges dominated the dielectric-related voltage shift in AlGaN/GaN MIS heterostructures, which caused a large voltage shift of -3 V with 10 nm Al2O3 thickness, while the flat-band voltage variety resulting from other types of charges was within 0.1 V.

  11. Profiling and Racial Profiling: An Interactive Exercise

    ERIC Educational Resources Information Center

    Semple, Philip

    2013-01-01

    Racial Profiling has been recognized as a serious problem that affects many segments of our society and is especially notable in law enforcement. Governments and police services have pronounced that racial profiling is not acceptable and will not be tolerated. They have gone to great lengths in trying to eradicate racial profiling through…

  12. Development of new measuring technique using sound velocity for CO2 concentration in Cameroonian volcanic lakes

    NASA Astrophysics Data System (ADS)

    Sanemasa, M.; Saiki, K.; Kaneko, K.; Ohba, T.; Kusakabe, M.; Tanyileke, G.; Hell, J.

    2012-12-01

    Nyos and Monoun were measured in March 2012, and CO2 concentration was calculated using the results of laboratory experiment. The CO2 concentration profiles by Sound Velocity Method were compared to estimated profile of 2012 by chemical analysis with correction using results of Kusakabe et al., 2008. The CO2 concentration profile estimated by Sound Velocity Method looks overestimated. This may be the effect of bicarbonate salt little existed in laboratory experiment. The change of sound velocity was evaluated as a linear function of CO2 and bicarbonate ion concentration by multiple regression analysis. Coefficient for the change of sound velocity of CO2 concentration in Lake Nyos agrees with the laboratory experiment within the precision of 10%. On the other hand, in Lake Monoun, the difference of coefficient is larger than 50%. In Lake Monoun, CO2 concentration may be estimated incorrectly because CO2/bicarbonate ratio seems to have changed. From these results, we concluded that Sound Velocity Method is useful to measure CO2 concentration quantitatively as far as the CO2/bicarbonate ratio does not change. The method is also applicable as an early diagnosis when the CO2 profile changes by a sudden CO2 injection to the lakes.

  13. Syphilis Profiles, 2012

    MedlinePlus

    ... STD on Facebook Data & Statistics Sexually Transmitted Diseases Syphilis Profiles, 2012 Recommend on Facebook Tweet Share Compartir ... Profiles The following profiles provide an overview of syphilis morbidity in each of the 50 states, the ...

  14. COMPENDEX Profiling Guide.

    ERIC Educational Resources Information Center

    Standera, Oldrich

    This manual provides instructions for completing the COMPENDEX (Computerized Engineering Index) Profile Submission Form used to prepare Current Information Selection (CIS) profiles. An annotated bibliography lists nine items useful in searching for proper profile words. (AB)

  15. The Influence of Tungsten on the Chemical Composition of a Temporally Evolving Nanostructure of a Model Ni-Al-Cr Superalloy

    NASA Technical Reports Server (NTRS)

    Sudbrack, Chantal K.; Isheim, Dieter; Noebe, Ronald D.; Jacobson, Nathan S.; Seidman, David N.

    2004-01-01

    The influence of W on the temporal evolution of gamma' precipitation toward equilibrium in a model Ni-Al-Cr alloy is investigated by three-dimensional atom-probe (3DAP) microscopy and transmission electron microscopy (TEM). We report on the alloys Ni-10 Al-8.5 Cr (at.%) and Ni-10 Al-8.5 Cr-2 W (at.%), which were aged isothermally in the gamma + gamma' two-phase field at 1073 K, for times ranging from 0.25 to 264 h. Spheroidal-shaped gamma' precipitates, 5-15 nm diameter, form during quenching from above the solvus temperature in both alloys at a high number density (approx. 10(exp 23/cu m). As gamma' precipitates grow with aging at 1073 K, a transition from spheriodal- to cuboidal-shaped precipitates is observed in both alloys. The elemental partitioning and spatially resolved concentration profiles across the gamma' precipitates are obtained as a function of aging time from three-dimensional atom-by-atom reconstructions. Proximity histogram concentration profiles of the quaternary alloy demonstrate that W concentration gradients exist in gamma' precipitates in the as-quenched and 0.25-h aging states, which disappear after 1 h of aging. The diffusion coefficient of W in gamma' is estimated to be 6.2 x 10(exp -20) sq m/s at 1073 K. The W addition decreases the coarsening rate constant, and leads to stronger partitioning of Al to gamma' and Cr to gamma.

  16. Grain boundary grooving of Al-bicrystals in the presence of a liquid Al-In alloy

    NASA Astrophysics Data System (ADS)

    Ratke, L.; Vogel, H. J.

    1987-02-01

    Grain boundary grooving of the Al bicrystal by diffusion of Al through an In-rich liquid was investigated at different temperatures below the monotectic. An instability of the groove profile is observed leading to a completely different groove profile than theoretically predicted by the theory of Mullins. The occurrence of this instability is explained by the existence of a second process disturbing the groove kinetics: grain boundary diffusion of In atoms into the bicrystal boundary.

  17. Solar Concentrator Advanced Development Program

    NASA Technical Reports Server (NTRS)

    Knasel, Don; Ehresman, Derik

    1989-01-01

    The Solar Concentrator Advanced Development Project has successfully designed, fabricated, and tested a full scale prototypical solar dynamic concentrator for space station applications. A Truss Hexagonal Panel reflector was selected as a viable solar concentrator concept to be used for space station applications. This concentrator utilizes a modular design approach and is flexible in attainable flux profiles and assembly techniques. The detailed design of the concentrator, which included structural, thermal and optical analysis, identified the feasibility of the design and specific technologies that were required to fabricate it. The needed surface accuracy of the reflectors surface was found to be very tight, within 5 mrad RMS slope error, and results in very close tolerances for fabrication. To meet the design requirements, a modular structure composed of hexagonal panels was used. The panels, made up of graphite epoxy box beams provided the strength, stiffness and dimensional stability needed. All initial project requirements were met or exceeded by hardware demonstration. Initial testing of structural repeatability of a seven panel portion of the concentrator was followed by assembly and testing of the full nineteen panel structure. The testing, which consisted of theodolite and optical measurements over an assembly-disassembly-reassembly cycle, demonstrated that the concentrator maintained the as-built contour and optical characteristics. The facet development effort within the project, which included developing the vapor deposited reflective facet, produced a viable design with demonstrated optical characteristics that are within the project goals.

  18. Geophysical implications of Io limb profile data

    NASA Astrophysics Data System (ADS)

    Nimmo, F.; Thomas, P. C.

    2013-12-01

    Limb profiles can be used both to determine a body's long-wavelength shape, and to infer its averaged elastic thickness [1]. Here we apply previously-developed techniques [1] to analyze Galileo limb profiles for Io [2], for comparison with control-point network analysis [3]. We determine Io's long-wavelength topography at spherical harmonic degrees 3 and 4. The amplitude of the topography is +/- 0.5 km, small compared to the degree-2 (tidal and rotational) shape. The l=4 components contain 4 times more power than l=3, consistent with tidal heating playing a role in producing topography [e.g. 4]. However, the topographic pattern is anti-symmetric about the equator, which is not expected from tidal models. Nor does the topography correlate with the global pattern of volcanoes and mountains [5]. The variation in limb profile roughness with wavelength can be used to infer an elastic thickness [1,6]. In the case of Io, despite local mountains, overall the topography is quite smooth. The highest-resolution limb profiles suggest an elastic thickness of about 50 km, higher than that of other outer solar system satellites [1]. This value is consistent with previous estimates based on the existence of mountains [7] and expectations of a thick, cold lid resulting from Io's heat loss being dominated by erupting melt [8]. [1] Nimmo et al. JGR 2011 [2] Thomas et al. Icarus 1998 [3] Oberst and Schuster JGR 2004 [4] Ross et al. Icarus 1990 [5] Kirchoff et al. EPSL 2011 [6] Araki et al. Science 2009 [7] Carr et al. Icarus 1998 [8] O'Reilly and Davies GRL 1981 Io long-wavelength topography, obtained from limb profile data and expanded from l=m=3 to l=m=4. Contour interval 0.1 km.

  19. Measurement of gradient index profile using deflectometry

    NASA Astrophysics Data System (ADS)

    Sekh, Md. Asraful; Biswas, Nisha Sood; Sarkar, Samir; Basuray, Amitabha

    2013-10-01

    The present paper reports a simple technique for measurement of one dimensional graded index (GRIN) profile using deflectometry. In this method the linear fringe pattern generated by a lateral shear interferometer using a Wollaston prism is made incident on the GRIN sample and the profile is measured from the deflection of the fringes. The method is simple and also gives a visual display of the GRIN profiles. Computation of the profile from the deflection of fringes is also simple. Measured data is compared with the theoretical ones obtained from the solution of the diffusion equation. Results are reported for negative refractive index profiles made by exchanging Na+ for Li+ ions in Na2O-Li2O-Al2O3-ZrO2-SiO2 glasses.

  20. New chemometric approach MCR-ALS to unmix EPR spectroscopic data from complex mixtures

    NASA Astrophysics Data System (ADS)

    Fadel, Maya Abou; de Juan, Anna; Touati, Nadia; Vezin, Hervé; Duponchel, Ludovic

    2014-11-01

    Electron paramagnetic resonance (EPR) spectra of mixtures are often difficult to interpret due to the superposition of spectral contribution of various species present in the complex materials. It is challenging to accurately identify the number of pure compounds present and to extract their pure spectra. In this study, the powerful chemometric method, multivariate curve resolution-alternating least squares (MCR-ALS), is applied to identify different paramagnetic centers. This method is used to simultaneously extract, with no prior knowledge, the pure spectra and the corresponding concentration profiles of all the compounds in the unknown and unresolved mixtures. The goal of our work is to apply, for the first time, this new chemometrics methodology, MCR-ALS, on EPR spectroscopic data in order to characterize a series of distinct but strongly overlapping spectra of various paramagnetic species.

  1. Plasma Efavirenz Concentrations Are Associated With Lipid and Glucose Concentrations

    PubMed Central

    Sinxadi, Phumla Zuleika; McIlleron, Helen Margaret; Dave, Joel Alex; Smith, Peter John; Levitt, Naomi Sharlene; Haas, David William; Maartens, Gary

    2016-01-01

    Abstract Efavirenz-based antiretroviral therapy (ART) has been associated with dyslipidemia and dysglycemia, risk factors for cardiovascular disease. However, the pathogenesis is not well understood. We characterized relationships between plasma efavirenz concentrations and lipid and glucose concentrations in HIV-infected South Africans. Participants on efavirenz-based ART were enrolled into a cross-sectional study. The oral glucose tolerance test was performed after an overnight fast, and plasma drawn for mid-dosing interval efavirenz, fasting total cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, and triglycerides concentrations. Among 106 participants (77 women), median age was 38 years, median CD4 + T-cell count was 322 cells/μL, median duration on ART was 18 months, and median (interquartile range) efavirenz concentration was 2.23 (1.66 to 4.10) μg/mL. On multivariable analyses (adjusting for age, sex, body mass index, and ART duration) doubling of efavirenz concentrations resulted in mean changes in mmol/L (95%CI) of: total cholesterol (0.40 [0.22 to 0.59]), LDL cholesterol (0.19 [0.04 to 0.30]), HDL cholesterol (0.14 [0.07 to 0.20]), triglycerides (0.17 [0.03 to 0.33]), fasting glucose (0.18 [0.03 to 0.33]), and 2-h glucose concentrations (0.33 [0.08 to 0.60]). Among 57 participants with CYP2B6 genotype data, associations between slow metabolizer genotypes and metabolic profiles were generally consistent with those for measured efavirenz concentrations. Higher plasma efavirenz concentrations are associated with higher plasma lipid and glucose concentrations. This may have implications for long-term cardiovascular complications of efavirenz-based ART, particularly among populations with high prevalence of CYP2B6 slow metabolizer genotypes. PMID:26765416

  2. Plasma Efavirenz Concentrations Are Associated With Lipid and Glucose Concentrations.

    PubMed

    Sinxadi, Phumla Zuleika; McIlleron, Helen Margaret; Dave, Joel Alex; Smith, Peter John; Levitt, Naomi Sharlene; Haas, David William; Maartens, Gary

    2016-01-01

    Efavirenz-based antiretroviral therapy (ART) has been associated with dyslipidemia and dysglycemia, risk factors for cardiovascular disease. However, the pathogenesis is not well understood. We characterized relationships between plasma efavirenz concentrations and lipid and glucose concentrations in HIV-infected South Africans.Participants on efavirenz-based ART were enrolled into a cross-sectional study. The oral glucose tolerance test was performed after an overnight fast, and plasma drawn for mid-dosing interval efavirenz, fasting total cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, and triglycerides concentrations.Among 106 participants (77 women), median age was 38 years, median CD4 + T-cell count was 322 cells/μL, median duration on ART was 18 months, and median (interquartile range) efavirenz concentration was 2.23 (1.66 to 4.10) μg/mL. On multivariable analyses (adjusting for age, sex, body mass index, and ART duration) doubling of efavirenz concentrations resulted in mean changes in mmol/L (95%CI) of: total cholesterol (0.40 [0.22 to 0.59]), LDL cholesterol (0.19 [0.04 to 0.30]), HDL cholesterol (0.14 [0.07 to 0.20]), triglycerides (0.17 [0.03 to 0.33]), fasting glucose (0.18 [0.03 to 0.33]), and 2-h glucose concentrations (0.33 [0.08 to 0.60]). Among 57 participants with CYP2B6 genotype data, associations between slow metabolizer genotypes and metabolic profiles were generally consistent with those for measured efavirenz concentrations.Higher plasma efavirenz concentrations are associated with higher plasma lipid and glucose concentrations. This may have implications for long-term cardiovascular complications of efavirenz-based ART, particularly among populations with high prevalence of CYP2B6 slow metabolizer genotypes. PMID:26765416

  3. CAN ABIOTIC (INORGANIC) PROCESSES ACCOUNT FOR HALOACETATE CONCENTRATION PROFILES?

    EPA Science Inventory

    Haloacetates comprise about 13% of the measurable halogenated organic matter in potable water supplies after chlorination. Some of these species have been linked with animal carcinogenesis and are regulated under the Stage 1 DBP Rule. However, it is known that post-disinfection p...

  4. Features of formation concentration profile in structured materials

    NASA Astrophysics Data System (ADS)

    Pavlenko, T. S.; Lisenkov, A. A.; Babinov, N. A.

    2016-01-01

    The paper presents analysis of dependence of the penetration depth of the implanted aluminium ions in structured titanium. Ion implantation was performed repetitively pulsed particle beam ion source "MEVVA-V.RU". In the interpretation of the observed patterns of energy accounted for heterogeneous composition of the beam vacuum-arc source, is represented by three components. Within the simulation found that in samples with relatively fine grains (ultrafine samples) largely contribute to diffusion processes, in particular radiation- induced diffusion in comparison with fine-grained samples.

  5. Biogenic flux of Al to sediment in the central equatorial Pacific Ocean: Evidence for increased productivity during glacial periods

    NASA Astrophysics Data System (ADS)

    Murray, R. W.; Leinen, M.; Isern, A. R.

    1993-10-01

    We examined the flux of Al to sediment accumulating beneath the zone of elevated productivity in the central equatorial Pacific Ocean, along a surface sediment transect at 135°W as well as downcore for a 650 kyr record at 1.3°N, 133.6°W. Across the surface transect, a pronounced, broadly equatorially symmetric increase in Al accumulation is observed, relative to Ti, with Al/Ti ratios reaching values 3-4 times that of potential detrital sources. The profile parallels biogenic accumulation and the modeled flux of particulate 234Th, suggesting rapid and preferential adsorptive removal of Al from seawater by settling biogenic particles. Normative calculations confirm that most Al is unsupported by the terrigenous fraction. The observed distributions are consistent with previous observations of the relative and absolute behavior of Al and Ti in seawater, and we can construct a reasonable mass balance between the amount of seawater-sourced Al retained in the sediment and the amount of seawater Al available in the overlying column. The close tie between Al/Ti and biogenic accumulation (as opposed to concentration) emphasizes that biogenic sedimentary Al/Ti responds to removal-transport phenomena and not bulk sediment composition. Thus, in these sediments dominated by the biogenic component, the bulk Al/Ti ratio reflects biogenic particle flux, and by extension, productivity of the overlying seawater. The downcore profile of Al/Ti at 1.3°N displays marked increases during glacial episodes, similar to that observed across the surface transect, from a background value near Al/Ti of average upper crust. The excursions in Al/Ti are stratigraphically coincident with maxima in both bulk and CaCO3 accumulation and the excess Al appears to not be preferentially affiliated with opaline or organic phases. Consistent with the similar behavioral removal of Al and 234Th, the latter of which responds to the total particle flux, the Al flux reflects carbonate accumulation only

  6. Suspended Solids Profiler Shop Test Report

    SciTech Connect

    STAEHR, T.W.

    2000-01-19

    The Suspended Solids Profiler (SSP) Instrument is planned to be installed in the AZ-101 tank to measure suspended solids concentrations during mixer pump testing. The SSP sensor uses a reflectance measurement principle to determine the suspended solids concentrations. The purpose of this test is to provide a documented means of verifying that the functional components of the SSP operate properly.

  7. Dynamic Concentration of Motors in Microtubule Arrays

    NASA Astrophysics Data System (ADS)

    Nédélec, François; Surrey, Thomas; Maggs, A. C.

    2001-04-01

    We present experimental and theoretical studies of the dynamics of molecular motors in microtubule arrays and asters. By solving a convection-diffusion equation we find that the density profile of motors in a two-dimensional aster is characterized by continuously varying exponents. Simulations are used to verify the assumptions of the continuum model. We observe the concentration profiles of kinesin moving in quasi-two-dimensional artificial asters by fluorescent microscopy and compare with our theoretical results.

  8. Solar concentrator with a toroidal relay module.

    PubMed

    Lin, Jhe-Syuan; Liang, Chao-Wen

    2015-10-01

    III-V multijunction solar cells require solar concentrators with a high concentration ratio to reduce per watt cost and to increase solar energy transforming efficiency. This paper discusses a novel solar concentrator design that features a high concentration ratio, high transfer efficiency, thin profile design, and a high solar acceptance angle. The optical design of the concentrator utilizes a toroidal relay module, which includes both the off-axis relay lens and field lens design in a single concentric toroidal lens shape. The optical design concept of the concentrator is discussed and the simulation results are shown. The given exemplary design has an aspect ratio of 0.24, a high averaged optical concentration ratio 1230×, a maximum efficiency of 76.8%, and the solar acceptance angle of ±0.9°. PMID:26479646

  9. Interdiffusion Behavior of Al-Rich Oxidation Resistant Coatings on Ferritic-Martensitic Alloys

    SciTech Connect

    Velraj, S.; Zhang, Ying; Hawkins, W. E.; Pint, Bruce A.

    2012-06-21

    We investigated interdiffusion of thin Al-rich coatings synthesized by chemical vapor deposition (CVD) and pack cementation on 9Cr ferritic–martensitic alloys in the temperature range of 650–700°C. The compositional changes after long-term exposures in laboratory air and air + 10 vol% H2O were examined experimentally. Interdiffusion was modeled by a modified coating oxidation and substrate interdiffusion model (COSIM) program. The modification enabled the program to directly input the concentration profiles of the as-deposited coating determined by electron probe microanalysis (EPMA). Reasonable agreement was achieved between the simulated and experimental Al profiles after exposures. Moreover, the model was also applied to predict coating lifetime at 650–700°C based on a minimum Al content (Cb) required at the coating surface to re-form protective oxide scale. In addition to a Cb value established from the failure of a thin CVD coating at 700°C, values reported for slurry aluminide coatings were also included in lifetime predictions.

  10. Exploitation of chemical profiles by conjugate variable analysis: application to the dating of a tropical ice core (Nevado Illimani, Bolivia)

    NASA Astrophysics Data System (ADS)

    Gay, M.; De Angelis, M.; Lacoume, J.-L.

    2013-06-01

    Ice core dating is a key parameter for the interpretation of the ice archives. However, the relationship between ice depth and age can generally not be easily established and requires to combine a large number of investigations and/or modeling effort. This paper presents a new approach of ice core dating based on conjugate variable (depth and spatial frequency) analysis of chemical profiles. The relationship between the depth of a given ice layer and the date it was deposited is determined using ion concentration depth profiles obtained along a one hundred-meters deep ice core recovered in the summit area of the Nevado Illimani (6350 m a.s.l.), located in the Eastern Bolivian Andes (16°37' S, 67°46' W). The results of Fourier conjugate analysis and wavelet tranforms are first compared. Both methods are applied to nitrate concentration depth profile. The resulting chronologies are checked by comparison with the multi-proxy year-by-year dating published by de Angelis et al. (2003) and with volcanic tie points, demonstrating the efficiency of Fourier conjugate analysis when tracking the natural variability of chemical proxies. The Fourier conjugate analysis is then applied to concentration depth profiles of seven other ions thus providing information on the suitability of each of them for dating studies of tropical Andean ice cores.

  11. Subtropical denudation rates of granitic regolith along a hill ridge in Longnan, SE China derived from cosmogenic nuclide depth-profiles

    NASA Astrophysics Data System (ADS)

    Cui, Li-Feng; Liu, Cong-Qiang; Xu, Sheng; Zhao, Zhi-Qi; Liu, Tao-Ze; Liu, Wen-Jing; Zhang, Zhuo-Jun

    2016-03-01

    The denudation rates of granitic regolith are essential to our understanding of the geomorphic changes and landscape evolution of a region and for soil resource management. We present denudation rates derived from four regolith profiles along a granitic slope in Longnan, southeastern China, using depth profiles of in-situ produced cosmogenic 10Be and 26Al. The concentration ranges of 10Be, 26Al, and 26Al/10Be ratio were 2.98 × 104-1.72 × 105 atoms/g, 2.18 × 105-1.12 × 106 atoms/g, and 6.07-7.50, respectively. Analysis of the results shows that the surface-lowering rates are 19 ± 3, 41 ± 4, 47 ± 4, 22 ± 3 m/Ma for the four profiles from the foot of the hill to the top along the hillslope. The mean denudation rate for the four profiles is ∼30 m/Ma. This rate is lower than that derived by other methods in nearby areas and also lower than the mean global denudation rate in basins deduced from 10Be levels in river sediment; this suggests an unevenness of the erosion process on a basin scale. The denudation rate at the ridge is twice that estimated for the summit and the foothill, indicating that the hillslope has not reached its steady state. Thus, the slopes below the ridge may become smoother and the ridge sharper in the long-term landscape evolution. The difference in topography may account for the variance among the profiles. In addition, bioturbation may have contributed to the lower concentration in the surface layer at the foot of the hill, producing a higher denudation rate than the average for the basin. The concentration of insoluble element Zr in the soil surface layer and fresh bedrock suggests that chemical weathering accounts for about one third of the denudation rate.

  12. Evaluating the adhesion of SU-8 thin films using an AlN/Si surface acoustic wave sensor

    NASA Astrophysics Data System (ADS)

    El Gowini, Mohamed M.; Moussa, Walied A.

    2015-03-01

    A new approach is developed for evaluating the adhesion of SU-8 thin films using a surface acoustic wave (SAW) sensor. The SAW sensor consists of a silicon (Si) substrate coated with a thin aluminum nitride (AlN) film and two sets of inter-digital electrodes (IDT) patterned on the AlN surface. Two sensor configurations are developed in order to evaluate the adhesion of SU-8. In the first configuration the SU-8 layer is patterned on top of a gold film that is deposited on the AlN surface. In the second configuration the gold film is coated with an omnicoat layer prior to patterning the SU-8 film. Omnicoat is an adhesion promoter for SU-8, which is used to increase its adhesion to gold. The frequency responses from both configurations are measured and the shift in the center frequency value is evaluated. The results illustrate that without omnicoat the center frequency shifts to a higher value indicating an increase in the wave velocity. This is because the poor adhesion of the SU-8 layer without omnicoat causes the wave to be more concentrated in the AlN/Si structure and AlN has a higher acoustic wave velocity in comparison to the SU-8 layer. In addition, four SAW sensors operating at four different center frequencies are developed to investigate the change in sensor sensitivity with the increase in center frequency. The results indicate that the sensor sensitivity increases proportionally to the increase in operating frequency. Finally, a theoretical model is developed to calculate the wave dispersion profile for the SU-8/AlN/Si configuration. The interface of the SU-8/AlN layers is modeled as a layer of mass-less springs with stiffness K(N m-3). The shifts in the wave dispersion profile at different levels of interface spring stiffness are compared to the experimental values to evaluate the adhesion of the SU-8 layer.

  13. REE chemistry and Sm-Nd systematics of late Archean weathering profiles in the Fortescue Group, Western Australia

    NASA Technical Reports Server (NTRS)

    MacFarlane, A. W.; Danielson, A.; Holland, H. D.; Jacobsen, S. B.

    1994-01-01

    Two weathering profiles, each consisting of an upper, sericite-rich zone and a lower, chlorite-rich zone, are preserved between flows of the Mt. Roe Basalt in the Fortescue Group, Hamersley Basin, Western Australia. REE concentrations in samples from these two profiles, which originally developed ca 2,760 Ma, show large variations depending on stratigraphic position. LREE abundances and (La/Yb)N are greatest at depths of 3-6 m below the paleosurface of the Mt. Roe #1 profile and are somewhat lower in samples above this level. The LREEs reach concentrations 6-9 times greater than in the underlying basalt, and thus appear to have been mobilized downward in the paleosol and concentrated in its middle part. LREE concentrations in the #2 profile show a similar distribution but with a sharp increase in all REE concentrations within 50 cm of the paleosurface. The distinction between the REE profiles in the two paleosols may be related to the difference in the overlying material. The #1 paleosol is overlain by a few meters of sediments and then by basalt, whereas the #2 paleosol is directly overlain by basalt. The LREEs appear to have been mobilized both during chemical weathering of the parental basalt and during later lower-greenschist-facies metamorphism and metasomatism of the paleosols. Remobilization of the REEs during the regional metamorphism of the Fortescue Group is confirmed by a whole-rock Sm-Nd reference isochron of Mt. Roe #1 samples with an age of 2,151 +/- 360 Ma. Variable initial 143Nd/144Nd values of unweathered basalt samples which may represent the paleosol protolith prevents a confident determination of the magnitude of LREE mobility. Both the initial mobilization of the REEs during weathering and the metasomatic remobilization appear to have taken place under redox conditions where Ce was present dominantly as Ce3+, because Ce anomalies are not developed within the sericite zone samples regardless of concentration. Europium anomalies in the

  14. REE chemistry and Sm-Nd systematics of late Archean weathering profiles in the Fortescue Group, Western Australia.

    PubMed

    MacFarlane, A W; Danielson, A; Holland, H D; Jacobsen, S B

    1994-04-01

    Two weathering profiles, each consisting of an upper, sericite-rich zone and a lower, chlorite-rich zone, are preserved between flows of the Mt. Roe Basalt in the Fortescue Group, Hamersley Basin, Western Australia. REE concentrations in samples from these two profiles, which originally developed ca 2,760 Ma, show large variations depending on stratigraphic position. LREE abundances and (La/Yb)N are greatest at depths of 3-6 m below the paleosurface of the Mt. Roe #1 profile and are somewhat lower in samples above this level. The LREEs reach concentrations 6-9 times greater than in the underlying basalt, and thus appear to have been mobilized downward in the paleosol and concentrated in its middle part. LREE concentrations in the #2 profile show a similar distribution but with a sharp increase in all REE concentrations within 50 cm of the paleosurface. The distinction between the REE profiles in the two paleosols may be related to the difference in the overlying material. The #1 paleosol is overlain by a few meters of sediments and then by basalt, whereas the #2 paleosol is directly overlain by basalt. The LREEs appear to have been mobilized both during chemical weathering of the parental basalt and during later lower-greenschist-facies metamorphism and metasomatism of the paleosols. Remobilization of the REEs during the regional metamorphism of the Fortescue Group is confirmed by a whole-rock Sm-Nd reference isochron of Mt. Roe #1 samples with an age of 2,151 +/- 360 Ma. Variable initial 143Nd/144Nd values of unweathered basalt samples which may represent the paleosol protolith prevents a confident determination of the magnitude of LREE mobility. Both the initial mobilization of the REEs during weathering and the metasomatic remobilization appear to have taken place under redox conditions where Ce was present dominantly as Ce3+, because Ce anomalies are not developed within the sericite zone samples regardless of concentration. Europium anomalies in the

  15. Changes of P, Ca, Al and Fe contents in fringe marshes along a pedogenic chronosequence in the Pearl River estuary, South China

    NASA Astrophysics Data System (ADS)

    Xiao, Rong; Bai, Junhong; Zhang, Honggang; Gao, Haifeng; Liu, Xinhui; Wilkes, Andreas

    2011-04-01

    Soil and plant samples were collected in four fringe marsh zones (i.e., A, B, C and D zones) along a pedogenic chronosequence in the Pearl River estuary in the Spring of 2009. Samples were subjected to a total digestion technique and analyzed for P, Ca, Al and Fe in order to study the changes of nutrient contents, storages in soils and their bioavailabilities to wetland plants (e.g. Cyperus malaccensis) in four zones. Results showed that soil Ca increased with depth along soil profiles, while P, Al and Fe generally kept constant in soil profiles in four zones. Al and Fe contents in the top 10 cm soils showed significant decreases from D to A zone, while a significant increase in Ca contents ( P<0.05). Significant increases along pedogenic chronosequence for P, Al and Fe at 30-40 cm soil horizons were also observed. Ca was mainly accumulated in plant aboveground parts; Al and Fe were accumulated in the belowground parts; while P was homogenously distributed among the tissues of C. malaccensis. C. malaccensis in D zone had lower Bio-concentration factors (BCFs) of P in the shoots and Al and Fe in the roots, and higher values of Ca in the shoots than those in older zones ( P<0.05). Compared to Al and Fe, both Ca and P had relatively higher translocation capacities for C. malaccensis, while only lower TFs for P and higher values for Al and Fe in D zone were observed than those in A and B zones ( P<0.05). Except for Al with no significant changes, the total BCFs for P and Fe showed an increasing trend with soil ages, while a decreasing trend for Ca. The total bio-storage factors (TBSFs) of P and Ca declined with the pedogenic time, whereas an increase for Fe. The results of this study can contribute to the wetland conservation and management in the Pearl River estuarine region.

  16. Density profiles of CDM microhalos and their implications for annihilation boost factors

    SciTech Connect

    Anderhalden, Donnino; Diemand, Juerg E-mail: diemand@physik.uzh.ch

    2013-04-01

    In a standard cold dark matter (CDM) cosmology, microhalos at the CDM cutoff scale are the first and smallest objects expected to form in the universe. Here we present results of high resolution simulations of three representative roughly Earth-mass microhalos in order to determine their inner density profile. We find that CDM microhalos in simulations without a cutoff in the power spectrum roughly follow the NFW density profile, just like the much larger CDM halos on galaxy and galaxy cluster scales. But having a cutoff in the initial power spectrum at a typical neutralino free streaming scale of 10{sup −7}M{sub s}un makes their inner density profiles considerably steeper, i.e. ρ∝r{sup −(1.3−1.4)}, in good agreement with the results from Ishiyama et al. (2010). An extrapolation of the halo and subhalo mass functions down to the cutoff scale indicates that microhalos are extremely abundant throughout the present day dark matter distribution and might contribute significantly to indirect dark matter detection signals. Assuming a transition from a NFW to a steeper inner profile (ρ∝r{sup −1.4}) two orders of magnitude above the cutoff scale, the total boost factor for a Milky Way sized dark matter halo increases from about 3.5 to 4. We further find that CDM microhalo concentrations are consistent with the Bullock et al. (2001) model and clearly rule out simplistic power law models for the mass dependence of concentrations and subhalo annihilation, which would erroneously lead to very large boost factors (a few hundred for galaxy halos and over 1000 for clusters)

  17. Cyclic Concentration Measurements for Characterizing Pulsating Flow

    SciTech Connect

    Bamberger, Judith A.

    2013-07-07

    Slurry mixed in vessels via pulse jet mixers has a periodic, rather than steady, concentration profile. Measurements of local concentration taken at the center of the tank at a range of elevations within the mixed region were analyzed to obtain a greater understanding of how the periodic pulse jet mixing cycle affects the local concentration. Data were obtained at the critical suspension velocity, when all solids are suspended at the end of the pulse. The data at a range of solids loadings are analyzed to observe the effect of solids concentration during the suspension and settling portions of the mixing cycle.

  18. Performance of Al-Rich Oxidation Resistant Coatings For Fe-Base Alloys

    SciTech Connect

    Pint, Bruce A

    2010-01-01

    Aluminum-rich coatings made by chemical vapor deposition and pack cementation on ferritic (e.g. Fe-9Cr-1Mo) and austenitic (Type 304L) substrates are being evaluated at 650-800 C. For oxidation testing, a humid air environment was used to quantify coating performance, as uncoated substrates experience rapid oxidation at these temperatures. A main goal of this work is to demonstrate the potential benefits and problems with alumina-forming coatings. The higher exposure temperatures were selected to accelerate the degradation of the coating by interdiffusion with the substrate. A general conclusion of this testing was that coatings with less Al and a ferritic Fe(Al) structure could be more durable than higher Al content aluminide coatings which have a large thermal expansion mismatch with these substrates. A lifetime model has been developed using diffusion and oxidation observations to predict coating performance as a function of temperature and initial coating composition. To test and improve the model, additional experiments are now being conducted to determine the effect of substrate composition (e.g. Cr content using Fe-12Cr and Fe-9Cr-2W substrates) and exposure temperature on the critical Al content for coating failure. Because of the unexpectedly low level of Al measured at coating failure ({approx}3.5at.% at 700 C), exposures of specimens with thick ({approx}200 {mu}m) high Al content coatings were stopped after 10kh at 800 C and 20kh at 700 C because extremely long times to failure were predicted. Post-exposure Al concentration profiles for these specimens were measured using electron microprobe.

  19. Performance of Al-rich Oxidation Resistant Coatings for Fe-Base Alloys

    SciTech Connect

    Pint, Bruce A; Zhang, Ying

    2011-01-01

    Aluminum-rich coatings made by chemical vapor deposition and pack cementation on ferritic (e.g. Fe-9Cr-1Mo) and austenitic (Type 304L) substrates are being evaluated at 650-800 C. For oxidation testing, a humid air environment was used to quantify coating performance, as uncoated substrates experience rapid oxidation at these temperatures. A main goal of this work is to demonstrate the potential benefits and problems with alumina-forming coatings. The higher exposure temperatures were selected to accelerate the degradation of the coating by interdiffusion with the substrate. A general conclusion of this testing was that coatings with less Al and a ferritic Fe(Al) structure could be more durable than higher Al content aluminide coatings which have a large thermal expansion mismatch with these substrates. A lifetime model has been developed using diffusion and oxidation observations to predict coating performance as a function of temperature and initial coating composition. To test and improve the model, additional experiments are now being conducted to determine the effect of substrate composition (e.g. Cr content using Fe-12Cr and Fe-9Cr-2W substrates) and exposure temperature on the critical Al content for coating failure. Because of the unexpectedly low level of Al measured at coating failure ({approx}3.5 at.% at 700 C), exposures of specimens with thick ({approx}200 {micro}m) high Al content coatings were stopped after 10kh at 800 C and 20kh at 700 C because extremely long times to failure were predicted. Post-exposure Al concentration profiles for these specimens were measured using electron microprobe.

  20. Performance of Al-Rich Oxidation Resistant Coatings for Fe-Base Alloys

    SciTech Connect

    Pint, Bruce A; Zhang, Ying

    2009-01-01

    Aluminum-rich coatings made by chemical vapor deposition and pack cementation on ferritic (e.g. Fe-9Cr-1Mo) and austenitic (Type 304L) substrates are bein