Science.gov

Sample records for al concentration profiles

  1. Interdiffusion in Ni-rich, Ni-Cr-Al alloys at 1100 and 1200 C. I - Diffusion paths and microstructures. II - Diffusion coefficients and predicted concentration profiles

    NASA Technical Reports Server (NTRS)

    Nesbitt, J. A.; Heckel, R. W.

    1987-01-01

    Interdiffusion in Ni-rich Ni-Cr-Al alloys is investigated experimentally after annealing at 1100 and 1200 C using gamma/gamma, gamma/gamma+beta, gamma/gamma+gamma prime, and gamma/gamma+alpha diffusion couples. The amount and location of Kirkendall porosity suggests that Al diffuses more rapidly than Cr which diffuses more rapidly than Ni in the gamma phase of Ni-Cr-Al alloys. The location and extent of maxima and minima in the concentration profiles of the diffusion couples indicate that both cross-term diffusion coefficients are positive. Measurements are also presented of the ternary interdiffusion coefficients of the gamma phase in the Ni-Cr-Al system. It is shown that the interdiffusion coefficients can be accurately predicted by using a ternary finite-difference interdiffusion model.

  2. Concentration profiles near an activated enzyme.

    PubMed

    Park, Soohyung; Agmon, Noam

    2008-09-25

    When a resting enzyme is activated, substrate concentration profile evolves in its vicinity, ultimately tending to steady state. We use modern theories for many-body effects on diffusion-influenced reactions to derive approximate analytical expressions for the steady-state profile and the Laplace transform of the transient concentration profiles. These show excellent agreement with accurate many-particle Brownian-dynamics simulations for the Michaelis-Menten kinetics. The steady-state profile has a hyperbolic dependence on the distance of the substrate from the enzyme, albeit with a prefactor containing the complexity of the many-body effects. These are most conspicuous for the substrate concentration at the surface of the enzyme. It shows an interesting transition as a function of the enzyme turnover rate. When it is high, the contact concentration decays monotonically to steady state. However, for slow turnover it is nonmonotonic, showing a minimum due to reversible substrate binding, then a maximum due to diffusion of new substrate toward the enzyme, and finally decay to steady state. Under certain conditions one can obtain a good estimate for the critical value of the turnover rate constant at the transition.

  3. 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.

  4. Concentration profiles of tritium penetrated into concrete

    SciTech Connect

    Takata, H.; Furuichi, K.; Nishikawa, M.; Fukada, S.; Katayama, K.; Takeishi, T.; Kobayashi, K.; Hayashi, T.; Namba, H.

    2008-07-15

    Concentration profiles of tritium in cement paste, mortar and concrete were measured after exposure to tritiated water vapor for a given time. Tritium penetrated a distance of about 5 cm from the exposed surface during an exposure of 6 months. The model of tritium behavior in concrete materials reported by the present authors was developed in this study with the consideration of the effects of sand and aggregate on both the diffusion coefficient of tritiated water vapor and the isotope exchange capacity. Predictive calculations based on the tritium transport model were also carried out in some situations of tritium leakage. The results of the calculations show that a large amount of tritium will be trapped in the concrete walls, and the trapped tritium will be gradually released back to the tritium handling room over the time of months to years even after the decontamination of the room is completed. (authors)

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Activated sludge pilot plant: comparison between experimental and predicted concentration profiles using three different modelling approaches.

    PubMed

    Le Moullec, Y; Potier, O; Gentric, C; Leclerc, J P

    2011-05-01

    This paper presents an experimental and numerical study of an activated sludge channel pilot plant. Concentration profiles of oxygen, COD, NO(3) and NH(4) have been measured for several operating conditions. These profiles have been compared to the simulated ones with three different modelling approaches, namely a systemic approach, CFD and compartmental modelling. For these three approaches, the kinetics model was the ASM-1 model (Henze et al., 2001). The three approaches allowed a reasonable simulation of all the concentration profiles except for ammonium for which the simulations results were far from the experimental ones. The analysis of the results showed that the role of the kinetics model is of primary importance for the prediction of activated sludge reactors performance. The fact that existing kinetics parameters in the literature have been determined by parametric optimisation using a systemic model limits the reliability of the prediction of local concentrations and of the local design of activated sludge reactors. PMID:21489593

  12. Al-26 production profile and model comparisons in Canyon Diablo

    NASA Astrophysics Data System (ADS)

    Michlovich, E.; Elmore, D.; Vogt, S.; Lipschutz, M.; Masarik, J.; Reedy, R. C.

    1993-03-01

    The large preatmospheric size of the Canyon Diablo meteorite, a radius of about 15 m, makes it especially suitable for systematic studies of cosmogenic nuclide production rates of iron objects in a 2 pi geometry. To reconstruct the exposure history of the meteoroid, Heymann et al. investigated several fragments recovered from known geographic locations around the crater for their shock features and cosmogenic nobel gases. They applied the Signer-Nier noble gas production rate model to establish the preatmospheric depth of the specimens in the meteoroid. Cosmic ray exposure ages suggested a multi-episodic irradiation, with 170 or 540 Ma being inferred for most of the samples studied while two anomalous specimens indicated a possible third exposure age at 940 Ma. Be-10 and Cl-36 have been measured in a number of these same samples by accelerator mass spectrometry (AMS), with use being made of the preatmospheric depths determined in Heymann et al. to construct production profiles. The present study extends the cosmogenic radionuclide data to Al-26 and compares the results with both the production rate model of Reedy and Arnold and production rates determined from the cross sections used by the Reedy-Arnold model (for the major nuclear reactions making Al-26) in combination with differential fluxes calculated using the Los Alamos High Energy Transport (LAHET) Code System. Model calculations for Be-10 and Cl-36 have also been obtained.

  13. Al-26 production profile and model comparisons in Canyon Diablo

    NASA Technical Reports Server (NTRS)

    Michlovich, E.; Elmore, D.; Vogt, S.; Lipschutz, M.; Masarik, J.; Reedy, R. C.

    1993-01-01

    The large preatmospheric size of the Canyon Diablo meteorite, a radius of about 15 m, makes it especially suitable for systematic studies of cosmogenic nuclide production rates of iron objects in a 2 pi geometry. To reconstruct the exposure history of the meteoroid, Heymann et al. investigated several fragments recovered from known geographic locations around the crater for their shock features and cosmogenic nobel gases. They applied the Signer-Nier noble gas production rate model to establish the preatmospheric depth of the specimens in the meteoroid. Cosmic ray exposure ages suggested a multi-episodic irradiation, with 170 or 540 Ma being inferred for most of the samples studied while two anomalous specimens indicated a possible third exposure age at 940 Ma. Be-10 and Cl-36 have been measured in a number of these same samples by accelerator mass spectrometry (AMS), with use being made of the preatmospheric depths determined in Heymann et al. to construct production profiles. The present study extends the cosmogenic radionuclide data to Al-26 and compares the results with both the production rate model of Reedy and Arnold and production rates determined from the cross sections used by the Reedy-Arnold model (for the major nuclear reactions making Al-26) in combination with differential fluxes calculated using the Los Alamos High Energy Transport (LAHET) Code System. Model calculations for Be-10 and Cl-36 have also been obtained.

  14. [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

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Estimating upper ocean phosphate concentrations using ARGO float temperature profiles

    NASA Astrophysics Data System (ADS)

    Kamykowski, Daniel

    2008-11-01

    The ARGO free-drifting profiling float array, with >3125 floats deployed between 60°N and 60°S latitudes at about 3° resolution as of May 2008 and each float profiling through 2000 m every 10 days, provides a comprehensive four-dimensional view of temperature and salinity in the world ocean. The resulting dataset complements satellite-based sea surface temperature (SST) measurements and similarly will complement future satellite-based sea surface salinity measurements. Although plans exist to add biogeochemical sensors to future floats, cost and depth restrictions may limit comprehensive upgrades to a fraction of all floats deployed after 2008. Temperature-nutrient (TN) relationships provide a mechanism to estimate nutrient concentrations from temperature to supplement sparser nutrient concentration measurements potentially obtained using non-chemical approaches like ISUS-based nitrate. Both negative and positive aspects of applying a temperature-phosphate (TP) linear regression matrix with global coverage (70°N and 70°S) are examined. The TP linear regression matrix was derived by combining an existing 1° latitude and longitude table of phosphate depletion temperatures (PDT) or X-intercepts with representative TP linear regression slopes derived from the GEOSECS dataset. Temperatures from datasets with associated latitude and longitude coordinates and, in some cases, measured phosphate concentrations ([PO 4]) were matched with calculated TP linear regression slopes and Y-intercepts in the global matrix with 1° resolution using MSExcel Lookup worksheet functions to calculate TP-estimated [PO 4]. The mean deviation of TP-estimated [PO 4] <3.0 μM from measured [PO 4] is 0.18±0.18 μM at Hawaii (HOT) and 0.04±0.08 μM at Bermuda (BATS) time series stations and 0.28±0.27 μM over all considered World Ocean Circulation Experiment (WOCE) stations representing the different ocean basins. In general, TP-estimated [PO 4] represents measured [PO 4] more accurately

  2. Measurements of radon gas concentrations in dwellings of Al-Madinah Al-Munawarah province in Saudi Arabia.

    PubMed

    Mohamed, R I; Alfull, Z Z; Dawood, N D

    2014-01-01

    Indoor radon concentration levels in a large number of dwellings in Al-Madinah Al-Munawarah Province have been measured. Al-Madinah Al-Munawarah is in the western region of Saudi Arabia. It is the second holiest city in Islam after Mecca, because it is the burial place of the Islamic Prophet Muhammad. The city was divided into four regions: western (contains nine sites), eastern (contains six sites), northern (contains nine sites) and southern (contains five sites). Radon gas concentration was measured using the closed chamber technique employing 2×2 cm(2) sheets of CR-39 solid-state nuclear track detectors. The detectors were kept for a period of 5 to 6 months from September 2010 to February 2011 in order to expose to radon gas. The results of the survey in the western and eastern sites showed that the overall minimum, maximum and average radon concentration levels were 20±1.6, 27±3.2 and 21±2.5 Bq m(-3), respectively. The lowest average radon concentration (20±1.6 Bq m(-3)) was found in Al Anabes and Al Suqya in the western region and Bani Dhafar in the eastern region, while the highest average concentration (27±3.2 Bq m(-3)) was found in Teeyba in the western region and Al 'Aridh in the eastern region, with an average of 21±2.5 Bq m(-3) in the western and eastern sites of Al-Madinah Al-Munawarah. Also in the northern region, the minimum radon concentration was 20±1.6 Bq m(-3) in Oyun, while the maximum was 42±1.6 Bq m(-3) in Sayyed al Shuhadd and Hai Nasr. In the southern region, the minimum radon concentration was 25±2.6 Bq m(-3) at Hai Al Hejrah, while the maximum value was 37±2.6 Bq m(-3) at Al Awali and Dawadia. The average radon concentration was 26±2.5 Bq m(-3) for Al-Madinah Al-Munawarah (western, eastern, northern and southern regions). The corresponding annual effective dose E (mSv y(-1)) to public from (222)Rn and its progeny was estimated to be 0.66 mSv y(-1) as an average value for Al-Madinah Al-Munawarah. The authors concluded that all

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. Origin and concentration profile of chromium in a Greek aquifer.

    PubMed

    Dermatas, Dimitris; Mpouras, Thanasis; Chrysochoou, Maria; Panagiotakis, Iraklis; Vatseris, Christos; Linardos, Nikos; Theologou, Eleni; Boboti, Nefeli; Xenidis, Anthimos; Papassiopi, Nymphodora; Sakellariou, Lefki

    2015-01-01

    In this paper the origin and concentration of chromium (Cr) in an ophiolitic aquifer in Vergina, northern Greece were investigated. The study area has only agricultural activity so that industrial Cr contamination was precluded. Soil sampling included topsoil and drillcore samples collected down to 98 m depth. Groundwater samples were collected from three existing wells and a spring at the area and from different depths of the soil boring using the discrete sampling method. Mineralogical analysis of soils confirmed the presence of ultramafic minerals, including chrysotile and chromite. Soil elemental analysis showed significant concentration of total chromium (Crtot; max 12,000 mg/kg) and hexavalent chromium (Cr(VI); max 7.5mg/kg). Significant Crtot (91 μg/L) and Cr(VI) (64 μg/L) concentrations exceeding the drinking water limit of 50 μg/L were also detected in groundwater. In both the discrete soil and groundwater samples a decreasing trend of Cr(VI) concentration was observed with increasing depth, while Crtot increased. The increasing trend in Crtot is attributed to the increasing contribution of unweathered ultramafic minerals with depth, while the decreasing Cr(VI) may be related to the increasing soil pH that does not favor Cr(III) oxidation by Mn-oxides.

  9. 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...

  10. 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.

  11. Compilation of atmospheric gas concentration profiles from 0 to 50 km

    NASA Technical Reports Server (NTRS)

    Smith, M. A. H.

    1982-01-01

    A set of 52 atmospheric gas concentration profiles between 0 and 50 km was compiled as a convenient reference data set for calculation of atmospheric infrared absorption or emission signals and for initialization of iterative procedures for retrieval of gas concentrations from measured data. The distributions of volume mixing ratio as a function of altitude generally correspond to typical diurnally averaged, seasonally averaged Northern Hemisphere midlatitude gas concentration profiles. Profiles are given for all gases included in current infrared atmospheric absorption line parameter compilations, and for a number of additional important trace gases.

  12. Weighted exponential regression for characterizing radionuclide concentrations in soil depth profiles

    SciTech Connect

    C.P.Oertel; J.R.Giles

    2009-11-01

    Characterization of radionuclide concentrations in soil profiles requires accurate evaluation of the depth distribution of the concentrations as measured by gamma emissions. An ongoing study based on 137Cs activity has shown that such concentration data generally follow an exponential trend when the fraction of radioactivity below depth is plotted against the depth. The slope of the exponential regression fit is defined as alpha/rho, the depth profile parameter. A weighted exponential regression procedure has been developed to compute a mean ??? for a group of related soil samples. Regression results from different areas or from different time periods can be used to compare representative radionuclide concentrations for the specified groupings.

  13. 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

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

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

    NASA Astrophysics Data System (ADS)

    D'Costa, Vijay Richard; Yeo, Yee-Chia

    2015-02-01

    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 × 1019 cm-3 and 336 cm2V-1s-1, respectively, were obtained. A phosphorus diffusivity of ˜1.2 × 10-13 cm2/s was obtained. The mobility versus carrier concentration relationships obtained for the implanted samples are close to the empirical relationship for bulk Ge.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Speciation of aqueous mononuclear Al(III)-hydroxo and other Al(III) complexes at concentrations of geochemical relevance by aluminum-27 nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Faust, Bruce C.; Labiosa, William B.; Dai, K'o. H.; MacFall, Janet S.; Browne, Bryant A.; Ribeiro, Anthony A.; Richter, Daniel D.

    1995-07-01

    Aluminum-27 (27Al) nuclear magnetic resonance (NMR) spectroscopy was used to characterize Al(III)-hydroxo complexes, in aqueous solutions with total Al(III) concentrations of 1.0-10 μM, using a custom-built NMR probe, coil, and sample bottle with low background aluminum impurities. Published 27Al NMR spectroscopy studies have traditionally used total Al(III) concentrations that are generally outside the range of geochemical interest (total [ Al(III) l ≥ 1000 μM). In this study, lower Al(III) concentrations (≤ 10 μM) were used to more closely approximate natural conditions, while allowing the measurement of mononuclear Al(III) species by 27Al NMR spectroscopy. The sensitivity of the 27Al NMR spectroscopy system, as measured by the signal-to-noise ratio (S/N), is S/N= 5 for 1.0 μM Al(III) at pH 2.00 and S/N= 3 for 10 μM Al(III) at pH 5.20. This level of sensitivity is within the range of geochemically relevant Al(III) concentrations found in slightly acidic natural waters. Quantitative models are developed which link observations of NMR chemical shifts and linewidth ratios to the calculated equilibrium speciation of mononuclear Al(III) for 10 μM Al(III) solutions at pH values 2.00 to 5.20 (prepared by titrating acidic AI(III) solutions with pyridine). Linear-regression best fits of the models to the NMR data are used to determine the intrinsic chemical shifts and linewidths of individual mononuclear Al(III) species. The intrinsic chemical shift of each Al(III) species "i", δi (ppm), is (1) δAl3+ ≡ 0 for Al3+ (defined by convention), (2) δAl(OH)2+ = 3.5 (SE= 1.3, N = 10) for Al(OH)2+, (3) δAl(OH)2+ ≅ 3.7 (SE= 1.4, N = 10) for Al(OH)2+ , and (4) δAl(OH)4- = 79.9 (SE= 0.03, N = 4) for Al(OH)4-; where positive chemical shifts are "downfield," SE = standard error, and N =number of samples. A convention is delineated in which the linewidth of the Al(III) species/peak of interest is normalized with respect to that of a reference species (Al3+) under the

  6. Sol-gel production of Cu/Al co-doped zinc oxide: Effect of Al co-doping concentration on its structure and optoelectronic properties

    NASA Astrophysics Data System (ADS)

    Bu, Ian Yi-Yu

    2014-12-01

    Sol-gel deposition of ZnO:Cu:Al thin films were co-doped different Cu:Al ratio. The optoelectronic and structural properties of the resultant film were evaluated using scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy, photoluminescence spectroscopy and UV-VIS spectroscopy. It was found that the Al content leads to narrowing of the band gap and that excessive Al doping concentration greater than 5 at% degrade the film's properties.

  7. Deposition of aluminium in tissues of rabbits exposed to inhalation of low concentrations of Al2O3 dust.

    PubMed Central

    Röllin, H B; Theodorou, P; Kilroe-Smith, T A

    1991-01-01

    With strong evidence coming to light for the toxicity of aluminium (Al), especially to the brain, investigation into the effects of inhalation of low concentrations of Al dust in animal models has become important. This study follows up previous observations on the effects of Al on the concentrations of essential metals in serum of workers exposed to inhalation of low concentrations of Al dust, with a study of the concentrations of Al in tissues of rabbits exposed to Al dust at one twentieth of the threshold limit value (TLV). Even at this low concentration, the amount of Al in the brains of these animals was nearly two and a half times as high as that of the control animals. The concentrations in other tissues were similar to normal. At the same time, the concentrations of Al in the serum was only slightly raised, indicating that this variable is a poor marker for the effects of Al on the body. It is suggested that an extensive study is needed to determine a more correct TLV and health based permissible concentration for occupational exposure to Al. PMID:2064977

  8. Soil water effects on concentration profiles and variations of 222Rn in a vadose zone.

    PubMed

    Fukui, M

    1987-08-01

    Concentration profiles of 222Rn and their variations were studied to understand the vertical motion in the ground caused by fluctuations of meteorological parameters, such as precipitation, ground-water level and atmospheric pressure. A method of trapping 222Rn was developed to measure the concentration profiles by circulating and bubbling soil gas in porous cups into toluene. For locations where the water table is close to the surface, observations showed a peak concentration in the vertical profile of 222Rn at about a 40-cm depth and revealed that the concentration in soil gas decreases as soil moisture increases near the water table. Soil gas in a buried vessel also was circulated continuously to monitor 222Rn in the ground air near the surface using an ionization chamber. A rising of the water table following precipitation causes a burst of 222Rn concentration by upflow in the ground, though the concentration in the soil gas soon decreases with the intake of air above the surface due to increasing atmospheric pressure following precipitation. The concentration in soil gas again increases via the phenomenon accompanying the recovery of equilibrium in soil water between 222Rn and 226Ra.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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...

  14. Effects of steady-state and variable ozone concentration profiles on pulmonary function

    SciTech Connect

    Hazucha, M.J.; Folinsbee, L.J.; Seal, E. Jr. )

    1992-12-01

    Measurements of ambient ozone (O2) concentration during daylight hours have shown a spectrum of concentration profiles, from a relatively stable to a variable pattern usually reaching a peak level in the early afternoon. Several recent studies have suggested that in estimating exposure dose (O3 concentration [C] x exposure time [T] x ventilation [V]), O3 concentration needs to be weighted more heavily than either ventilation or duration of exposure in the estimates. In this study we tested the hypothesis that regardless of concentration pattern and exposure rate the same exposure dose of O3 will induce the same spirometric response. We exposed 23 healthy male volunteers (20 to 35 yr of age) for 8 h to air, 0.12 ppm O3 (steady-state), and a triangular exposure pattern (concentration increased steadily from zero to 0.24 ppm over the first 4 h and decreased back to zero by 8 h). During the first 30 min of each hour, subjects exercised for 30 min at minute ventilation (VE) approximately 40 L/min. The order of the exposures was randomized, and the exposures were separated by at least 7 days. The response patterns over the 8-h periods for spirometric variables in both O3 exposures were statistically different from air exposure changes and from each other. For FEV1 the p values were 0.017 between air and steady-state profile, 0.002 between air and triangular profile, and 0.037 between steady-state and triangular profiles. Although in the triangular pattern of exposure the maximal O3 concentration was reached at 4 h, the maximum FEV1 decrement (10.2%) was observed at 6 h of exposure.

  15. 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.

  16. Stratospheric HBr concentration profile obtained from far-infrared emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Nolt, I. G.; Ade, P. A. R.; Alboni, F.; Carli, B.; Carlotti, M.; Cortesi, U.; Epifani, M.; Griffin, M. J.; Hamilton, P. A.; Lee, C.; Lepri, G.; Mencaraglia, F.; Murray, A. G.; Park, J. H.; Park, K.; Raspollini, P.; Ridolfi, M.; Vanek, M. D.

    Hydrogen bromide (HBr) is the principal bromine sink species for the ozone loss chemistry induced by bromine-containing gases in the stratosphere. We report a 1994 balloon-based measurement of the daytime stratospheric HBr profile between 20 and 36.5 km altitude. The average concentration result of 1.31±0.39 parts per trillion in volume (pptv) and an analysis for the concentration versus altitude profile are consistent with previously reported measurements. These results strengthen the evidence for a significantly higher HBr concentration than that predicted by current photochemical models which, on the basis of recent kinetics results, do not include significant HBr production by the reaction branch, BrO + HO2 → HBr + O3.

  17. 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.

  18. Concentration profiles from lidar measurements in the presence of multiple scattering: the two-stream approximation

    SciTech Connect

    Ayoubi, I.S.; Nelson, P. )

    1989-10-01

    We consider the problem of obtaining, from monostatic lidar measurements, the concentration profile for a medium of known scattering properties. Invariant imbedding methods are applied to the two-stream approximation to the radiative transfer equation in one dimension, to obtain a nonlinear integrodifferential equation that takes account of multiple scattering events, and whose solution yields the desired profile. A discretization scheme for this equation is presented, along with results from using it to solve two sample problems. The stability of this inversion scheme in the face of noisy signals is also explored.

  19. 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.

  20. 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

  1. 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.

  2. 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.

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

    PubMed

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

    2010-05-01

    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 1h 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 microg/L, and the corresponding brevetoxin level of Florida red tide aerosol ranged between 21 and 39 ng/m(3). 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.

  4. 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

  5. Effects of Al concentration on microstructural characteristics and electrical properties of Al-doped ZnO thin films on Si substrates by atomic layer deposition.

    PubMed

    Lee, Ju Ho; Lee, Jae-Won; Hwang, Sooyeon; Kim, Sang Yun; Cho, Hyung Koun; Lee, Jeong Yong; Park, Jin-Seong

    2012-07-01

    Al-doped ZnO (AZO) thin films with various Al concentrations were synthesized on Si(001) substrates with native oxide layers by atomic layer deposition process. The effects of the Al concentration on the microstructural characteristics of the AZO thin films grown at 250 degrees C and the correlation between their microstructural characteristics and electrical properties of the AZO thin films were investigated by AFM, XRD, HRTEM and Hall measurements. The XRD and HRTEM results revealed that the crystallinity and electrical properties of the undoped ZnO thin films were enhanced by 2.48 at% Al doping. However, 12.62 at% Al doping induced the deterioration of their crystallinity and electrical properties due to the formation of nano-sized metallic Al clusters and randomly oriented ZnO-based nano-crystals. To enhance the electrical properties of the AZO thin films while maintaining their crystallinity and electrical properties, a moderate Al concentration has to be chosen under the solubility limit of Al in ZnO.

  6. The form of the profile of heterointerfaces in (311)Ga GaAs/AlAs structures

    SciTech Connect

    Gulyaev, D. V. Zhuravlev, K. S.

    2010-03-15

    The steady-state photoluminescence and kinetics of photoluminescence of the (100)-oriented and (311)Ga-oriented type II GaAs/AlAs superlattices are studied under the effect of the electric field of the surface acoustic wave. It is found that, in the (100)-oriented structures, the drop of intensity of steady-state photoluminescence and acceleration of photoluminescence kinetics are independent of the direction of the electric field of the surface acoustic wave with respect to crystallographic directions, while in the (311)Ga-oriented structures these effects are anisotropic. It is shown that all variations in the steady-state photoluminescence and in kinetics of photoluminescence of (100)-oriented and (311)Ga-oriented structures under the effect of the electric field of the acoustic wave are associated with transfer and capture by the nonradiative recombination centers of nonequilibrium charge carriers, which are initially localized in wide quantum wells formed by fluctuations of the thickness of the layers of the structures. From the obtained experimental data, the parameters of the profile of heterointerfaces of the (311)Ga GaAs/AlAs superlattices are determined. It is established that the lateral sizes of microgrooves in the [011] direction on the direct and inverse heterointerfaces of the (311)Ga superlattices exceed 3.2 nm, while the modulation of the thickness of the AlAs layers is from 0.8 to 1.2 nm.

  7. 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

  8. The global extrapolation of numerical methods for computing concentration profiles in percutaneous drug absorption.

    PubMed

    Twizell, E H

    1989-01-01

    A family of numerical methods is developed and analyzed for the numerical solution of the parabolic partial differential equation together with the associated initial and boundary conditions, which arise in a mathematical model of the transient stage of percutaneous drug absorption. Two global extrapolation procedures are described, the first in time only, the second in both space and time, for improving the accuracy of the computed concentration profiles. The behaviours of two members of the family of methods, before and after extrapolation, are examined by repeating a number of experiments reported in the literature. Modifications to the algorithms, which are necessary in computing concentration profiles after the ointment is removed at the steady state, are outlined.

  9. 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.

  10. Determining concentration depth profiles of thin foam films with neutral impact collision ion scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Ridings, Christiaan; Andersson, Gunther G.

    2010-11-01

    Equipment is developed to measure the concentration depth profiles in foam films with the vacuum based technique neutral impact collision ion scattering spectroscopy. Thin foam films have not previously been investigated using vacuum based techniques, hence specialized methods and equipment have been developed for generating and equilibrating of foam films under vacuum. A specialized film holder has been developed that encloses the foam film in a pressure cell. The pressure cell is air-tight except for apertures that allow for the entrance and exit of the ion beam to facilitate the analysis with the ion scattering technique. The cell is supplied with a reservoir of solvent which evaporates upon evacuating the main chamber. This causes the cell to be maintained at the vapor pressure of the solvent, thus minimizing further evaporation from the films. In order to investigate the effect of varying the pressure over the films, a hydrostatic pressure is applied to the foam films. Concentration depth profiles of the elements in a thin foam film made from a solution of glycerol and the cationic surfactant hexadecyltrimethylammonium bromide (C16TAB) were measured. The measured concentration depth profiles are used to compare the charge distribution in foam films with the charge distribution at the surface of a bulk solution. A greater charge separation was observed at the films' surface compared to the bulk surface, which implies a greater electrostatic force contribution to the stabilization of thin foam films.

  11. Analytical Expression for the NO Concentration Profile Following NONOate Decomposition in the Presence of Oxygen.

    PubMed

    Rong, Zimei; Ye, Zhihui

    2016-01-01

    We have derived an analytical expression for the time dependent NO concentration from NONOate donors in the presence of oxygen for the process of NO release from NO donors following autoxidation. This analytical solution incorporates the kinetics of the releases with the autoxidation and is used to fit the simulated NO concentration profile to the experimental data. This allows one to determine the NO release rate constant, k 1, the NO release stoichiometric coefficient, v NO, and the NO autoxidation reaction rate constant, k 2. This analytical solution also allows us to predict the real NO concentration released from NO donors under aerobic conditions, while v NO is reportedly two under aerobic conditions, it falls to lower values in the presence of oxygen. PMID:27526174

  12. Interaction of silver nanoparticles with proteins: a characteristic protein concentration dependent profile of SPR signal.

    PubMed

    Banerjee, Victor; Das, K P

    2013-11-01

    Silver nanoparticles are finding increasing applications in biological systems, for example as antimicrobial agents and potential candidates for control drug release systems. In all such applications, silver nanoparticles interact with proteins and other biomolecules. Hence, the study of such interactions is of considerable importance. While BSA has been extensively used as a model protein for the study of interaction with the silver nanoparticles, studies using other proteins are rather limited. The interaction of silver nanoparticles with light leads to collective oscillation of the conducting electrons giving rise to surface plasmon resonance (SPR). Here, we have studied the protein concentration dependence of the SPR band profiles for a number of proteins. We found that for all the proteins, with increase in concentration, the SPR band intensity initially decreased, reaching minima and then increased again leading to a characteristic "dip and rise" pattern. Minimum point of the pattern appeared to be related to the isoelectric point of the proteins. Detailed dynamic light scattering and transmission electron microscopy studies revealed that the consistency of SPR profile was dependent on the average particle size and state of association of the silver nanoparticles with the change in the protein concentration. Fluorescence spectroscopic studies showed the binding constants of the proteins with the silver nanoparticles were in the nano molar range with more than one nanoparticle binding to protein molecule. Structural studies demonstrate that protein retains its native-like structure on the nanoparticle surface unless the molar ratio of silver nanoparticles to protein exceeds 10. Our study reveals that nature of the protein concentration dependent profile of SPR signal is a general phenomena and mostly independent of the size and structure of the proteins.

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

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

    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 m2 and has 350 palm trees and the second farm is about 7000 m2 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/m3. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. Different shapes of impurity concentration profiles formed by long-range interstitial migration

    NASA Astrophysics Data System (ADS)

    Velichko, O. I.

    2016-09-01

    A model of interstitial impurity migration is proposed which explains the redistribution of ion-implanted boron in low-temperature annealing of nonamorphized silicon layers. It is supposed that nonequilibrium boron interstitials are generated either in the course of ion implantation or at the initial stage of thermal treatment and that they migrate inward and to the surface of a semiconductor in the basic stage of annealing. It is shown that the form of the “tail” in the boron profile with the logarithmic concentration axis changes from a straight line if the average lifetime of impurity interstitials is substantially shorter than the annealing duration to that bending upwards for increasing lifetime. The calculated impurity concentration profiles are in excellent agreement with the experimental data describing the redistribution of implanted boron for low-temperature annealing at 750∘C for 1h and at 800∘C for 35min. Simultaneously, the experimental phenomenon of incomplete electrical activation of boron atoms in the “tail” region is naturally explained.

  3. 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

  4. [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

  5. Antibiotic Abscess Penetration: Fosfomycin Levels Measured in Pus and Simulated Concentration-Time Profiles

    PubMed Central

    Sauermann, Robert; Karch, Rudolf; Langenberger, Herbert; Kettenbach, Joachim; Mayer-Helm, Bernhard; Petsch, Martina; Wagner, Claudia; Sautner, Thomas; Gattringer, Rainer; Karanikas, Georgios; Joukhadar, Christian

    2005-01-01

    The present study was performed to evaluate the ability of fosfomycin, a broad-spectrum antibiotic, to penetrate into abscess fluid. Twelve patients scheduled for surgical or computer tomography-guided abscess drainage received a single intravenous dose of 8 g of fosfomycin. The fosfomycin concentrations in plasma over time and in pus upon drainage were determined. A pharmacokinetic model was developed to estimate the concentration-time profile of fosfomycin in pus. Individual fosfomycin concentrations in abscess fluid at drainage varied substantially, ranging from below the limit of detection up to 168 mg/liter. The fosfomycin concentrations in pus of the study population correlated neither with plasma levels nor with the individual ratios of abscess surface area to volume. This finding was attributed to highly variable abscess permeability. The average concentration in pus was calculated to be 182 ± 64 mg/liter at steady state, exceeding the MIC50/90s of several bacterial species which are commonly involved in abscess formation, such as streptococci, staphylococci, and Escherichia coli. Hereby, the exceptionally long mean half-life of fosfomycin of 32 ± 39 h in abscess fluid may favor its antimicrobial effect because fosfomycin exerts time-dependent killing. After an initial loading dose of 10 to 12 g, fosfomycin should be administered at doses of 8 g three times per day to reach sufficient concentrations in abscess fluid and plasma. Applying this dosing regimen, fosfomycin levels in abscess fluid are expected to be effective after multiple doses in most patients. PMID:16251282

  6. 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.

  7. Effect of freezing rate and dendritic ice formation on concentration profiles of proteins frozen in cylindrical vessels.

    PubMed

    Rodrigues, Miguel A; Miller, Maria A; Glass, Matt A; Singh, Satish K; Johnston, Keith P

    2011-04-01

    The process of freezing protein solutions can perturb the conformation of the protein and potentially lead to aggregate formation during long-term storage in the frozen state. Radial macroscopic freeze concentration and temperature profiles for bovine serum albumin (BSA) solutions in small cylindrical stainless steel vessels were determined for various freezing rates. The measured concentrations of both BSA and immunoglobulin G2, as well as trehalose in sampled ice sections, increased by up to twofold to threefold toward the bottom and radial center for slow freezing rates produced in stagnant air freezers. The concentration and temperature profiles result in density gradients that transport solutes by convective flow. For faster external cooling by either forced convection of air or a liquid coolant, the increased freezing rate raised the ice front velocity resulting in enhanced dendritic ice growth. The ice trapped the solutes more effectively before they were removed from the ice front by diffusion and convection, resulting in more uniform solute concentration profiles. The dynamic temperature profiles from multiple radial thermocouples were consistent with the independently measured freeze concentration profiles. The ability to control the protein concentration profile in the frozen state offers the potential to improve stability of protein in long-term frozen storage.

  8. 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.

  9. 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

  10. Spatial profiles of potential, ion concentration and flux in short unipolar and bipolar nanopores.

    PubMed

    Tajparast, Mohammad; Virdi, Gautam; Glavinović, Mladen I

    2015-10-01

    During release of vesicular content the resistance of the fusion pore sometimes changes rapidly and repeatedly. However, it is not clear why the pore 'flickers'. Engineered nanopores often rectify, but how different factors influence the rectification requires clarification. To better understand the ionic 'causes' of pore conductivity and its changes we simulated ion transport through a short nanopore using Poisson-Nernst-Planck equations, coupling it to the transport of water using Navier-Stokes equations. We extracted the potential, concentration, and ion flux profiles. In uniformly charged nanopores the voltage bias determines which counter-ion flux dominates, and it is carried by the counter-ions of the highest concentration. In unipolar nanopores this simple rule breaks down. The dominant counter-ion in the charged half is from the adjacent compartment, but the bias determines what counter-ion flux is dominant--the same ion (regular bias), or a different and smaller (reverse bias), and this difference determines the level of rectification. In bipolar nanopores the dominant counter-ions in each half are from the adjacent compartments, and the total ion concentration dips in the middle near the wall. With regular bias the total ion concentration peaks in the pore center; the ions that carry the current through the nanopore start as counter-ions and their fluxes are large. With reverse bias the total concentration dips near the wall and in the center, both dominant ion fluxes through the nanopore start as co-ions and are very small, whereas those starting as counter-ions do not go through.

  11. 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.

  12. 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.

  13. Detailed arsenic concentration profiles at Si/SiO[sub 2] interfaces

    SciTech Connect

    Pei, Lirong; Duscher, Gerd; Steen, Christian; Pichler, Peter; Ryssel, Heiner; Napolitani, Enrico; De Salvador, Davide; Piro, Alberto Maria; Terrasi, Antonio; Severac, Fabrice; Cristiano, Filadelfo; Ravichandran, Karthik; Gupta, Naveen; Windl, Wolfgang

    2008-01-01

    The pile-up of arsenic at the Si/SiO2 interface after As implantation and annealing was investigated by high resolution Z-contrast imaging, electron energy-loss spectroscopy EELS, grazing incidence x-ray fluorescence spectroscopy GI-XRF, secondary ion mass spectrometry, x-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, as well as Hall mobility and four-point probe resistivity measurements. After properly taking into account their respective artifacts, the results of all methods are compatible with each other, with EELS and GI-XRF combined with etching providing similar spatial resolution on the nanometer scale for the dopant profile. The sheet concentration of the piled-up As at the interface was found to be 11015 cm 2 for an implanted dose of 11016 cm 2 with a maximum concentration of 10 at. %. The strain observed in the Z-contrast images also suggests a significant concentration of local distortions within 3 nm from the interface, which, however, do not seem to involve intrinsic point defects. 2008 American Institute of Physics.

  14. A neural network method for restoring the initial impurity concentration distribution from data of ion sputter depth profiling

    NASA Astrophysics Data System (ADS)

    Shyrokorad, D. V.; Kornich, G. V.

    2016-07-01

    A new approach to solving the problem of restoring the initial impurity concentration distribution from data of ion sputter depth profiling is proposed. The algorithm of impurity profile restoration is based on using an artificial neural network with the input signals representing surface concentrations of impurity determined at sequential moments of sputter depth profiling. The artificial neural network is trained for various depths and thicknesses of the impurity-containing layer and various values of parameters of the adopted model equation of diffusion-like ion mixing.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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...

  20. 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

  1. 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.

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

    PubMed

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

    2014-08-01

    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.

  3. 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.

  4. 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.

  5. Spectra and concentration profiles throughout the reaction of curing epoxy resins from near-infrared spectroscopy and multivariate curve resolution methods.

    PubMed

    Larrechi, M S; Rius, F X

    2004-01-01

    When applied to near-infrared (NIR) data, multivariate curve resolution methods, in particular alternating least squares (ALS), make it possible to calculate the concentration profiles and the spectra of all species involved in the reaction of curing epoxy resins. In this paper, the model reaction between phenyl glicidyl ether and aniline (2:1) was studied at 95 degrees C. A NIR spectrum was recorded every five minutes throughout the eight-hour reaction process. The data display rank deficiency. This problem was overcome by supplying additional information to the system in the form of known spectra of some reactants. The recovered spectra and concentration profiles satisfactorily reproduced the experimental data. In this way, 99.99% of the variance associated with the experimental matrix was reproduced. A value of 0.87% was obtained for lack of fit while the similarity coefficient r between the spectra recovered and the spectra corresponding to the three pure species involved in the reaction were PGE (r = 0.994), aniline (r = 0.994), and tertiary amine (r = 0.999). The maximum and minimum limits associated with the ALS solutions were calculated, which made it possible to limit to a considerable extent the ambiguity that is characteristic of these curve resolution methods.

  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. 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

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. GaAs, AlGaAs and InGaP Tunnel Junctions for Multi-Junction Solar Cells Under Concentration: Resistance Study

    SciTech Connect

    Wheeldon, Jeffrey F.; Valdivia, Christopher E.; Walker, Alex; Kolhatkar, Gitanja; Hall, Trevor J.; Hinzer, Karin; Masson, Denis; Riel, Bruno; Fafard, Simon; Jaouad, Abdelatif; Turala, Artur; Ares, Richard; Aimez, Vincent

    2010-10-14

    The following four TJ designs, AlGaAs/AlGaAs, GaAs/GaAs, AlGaAs/InGaP and AlGaAs/GaAs are studied to determine minimum doping concentration to achieve a resistance of <10{sup -4} {omega}{center_dot}cm{sup 2} and a peak tunneling current suitable for MJ solar cells up to 1500-suns concentration (operating current of 21 A/cm{sup 2}). Experimentally calibrated numerical models are used to determine how the resistance changes as a function of doping concentration. The AlGaAs/GaAs TJ design is determined to require the least doping concentration to achieve the specified resistance and peak tunneling current, followed by the GaAs/GaAs, and AlGaAs/AlGaAs TJ designs. The AlGaAs/InGaP TJ design can only achieve resistances >5x10{sup -4} {omega}cm{sup 2}.

  14. 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

  15. Effect of whey protein concentrate and sodium chloride concentrations on the odour profile of sous vide cooked whole-muscle beef from Argentina.

    PubMed

    Grigioni, G; Langman, L; Szerman, N; Irurueta, M; Vaudagna, S R

    2008-07-01

    Semitendinosus muscles added with whey protein concentrate (WPC) and sodium chloride (NaCl) were submitted to sous vide cooking. Four enhancement treatments and a control were tested: 0.875% WPC (w/w)+0.625% NaCl, 2.625% WPC+0.625% NaCl, 0.875% WPC+1.875% NaCl, 2.625% WPC+1.875% NaCl, and control (non-injected muscles). Odour analyses were carried out with an electronic nose (EN) system. EN data were evaluated applying Principal Component Analysis, Linear Discriminant Analysis and Partial Least Squares algorithm. EN was able to discriminate the odour profiles of cooked enhanced beef as a function of the amount of WPC added. No significant differences in odour profiles were observed regarding NaCl concentration. These results agreed with those obtained when odour profiles were analysed in WPC dispersions. The reported results support the applicability of EN methodology for analysing the impact of processing parameters on beef odour profiles. PMID:22062918

  16. Effect of whey protein concentrate and sodium chloride concentrations on the odour profile of sous vide cooked whole-muscle beef from Argentina.

    PubMed

    Grigioni, G; Langman, L; Szerman, N; Irurueta, M; Vaudagna, S R

    2008-07-01

    Semitendinosus muscles added with whey protein concentrate (WPC) and sodium chloride (NaCl) were submitted to sous vide cooking. Four enhancement treatments and a control were tested: 0.875% WPC (w/w)+0.625% NaCl, 2.625% WPC+0.625% NaCl, 0.875% WPC+1.875% NaCl, 2.625% WPC+1.875% NaCl, and control (non-injected muscles). Odour analyses were carried out with an electronic nose (EN) system. EN data were evaluated applying Principal Component Analysis, Linear Discriminant Analysis and Partial Least Squares algorithm. EN was able to discriminate the odour profiles of cooked enhanced beef as a function of the amount of WPC added. No significant differences in odour profiles were observed regarding NaCl concentration. These results agreed with those obtained when odour profiles were analysed in WPC dispersions. The reported results support the applicability of EN methodology for analysing the impact of processing parameters on beef odour profiles.

  17. 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.

  18. Glucose ameliorates the metabolic profile and mitochondrial function of platelet concentrates during storage in autologous plasma

    PubMed Central

    Amorini, Angela M.; Tuttobene, Michele; Tomasello, Flora M.; Biazzo, Filomena; Gullotta, Stefano; De Pinto, Vito; Lazzarino, Giuseppe; Tavazzi, Barbara

    2013-01-01

    Background It is essential that the quality of platelet metabolism and function remains high during storage in order to ensure the clinical effectiveness of a platelet transfusion. New storage conditions and additives are constantly evaluated in order to achieve this. Using glucose as a substrate is controversial because of its potential connection with increased lactate production and decreased pH, both parameters triggering the platelet lesion during storage. Materials and methods In this study, we analysed the morphological status and metabolic profile of platelets stored for various periods in autologous plasma enriched with increasing glucose concentrations (13.75, 27.5 and 55 mM). After 0, 2, 4, 6 and 8 days, high energy phosphates (ATP, GTP, ADP, AMP), oxypurines (hypoxanthine, xanthine, uric acid), lactate, pH, mitochondrial function, cell lysis and morphology, were evaluated. Results The data showed a significant dose-dependent improvement of the different parameters in platelets stored with increasing glucose, compared to what detected in controls. Interestingly, this phenomenon was more marked at the highest level of glucose tested and in the period of time generally used for platelet transfusion (0–6 days). Conclusion These results indicate that the addition of glucose during platelet storage ameliorates, in a dose-dependent manner, the biochemical parameters related to energy metabolism and mitochondrial function. Since there was no correspondence between glucose addition, lactate increase and pH decrease in our experiments, it is conceivable that platelet derangement during storage is not directly caused by glucose through an increase of anaerobic glycolysis, but rather to a loss of mitochondrial functions caused by reduced substrate availability. PMID:22682337

  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. 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.; Mcneely, J. B.; Barnett, A. M.

    1991-01-01

    The AstroPower self-supporting, transparent AlGaAs top solar cell can be stacked upon any well-developed bottom solar cell for improved system performance. This is an approach to improve the performance and scale of space photovoltaic power systems. Mechanically stacked tandem solar cell concentrator systems based on the AlGaAs top concentrator solar cell can provide near term efficiencies of 36 percent (AMO, 100x). Possible tandem stack efficiencies greater than 38 percent (100x, AMO) are feasible with a careful selection of materials. In a three solar cell stack, system efficiencies exceed 41 percent (100x, AMO). These device results demonstrate a practical solution for a state-of-the-art top solar cell for attachment to an existing, well-developed solar cell.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Persistent chlordane concentrations in long island sound sediment: Implications from chlordane, 210Pb, and 137Cs profiles

    USGS Publications Warehouse

    Yang, L.; Li, X.; Crusius, J.; Jans, U.; Melcer, M.E.; Zhang, P.

    2007-01-01

    Concentrations of chlordane, a banned termiticide and pesticide, were examined in recently collected surficial sediment (10 sites) and sediment cores (4 sites) in Long Island Sound (LIS).The highest chlordane concentrations were observed in western LIS, near highly urbanized areas. Chlordane concentrations did not decrease significantly in the past decade when compared to the data collected in 1996, consistent with the observation of near-constant chlordane levels in blue mussel tissues collected during the same time period. Chlordane concentrations in many of the sites exceeded levels above which harmful effects on sediment-dwelling organisms are expected to frequently occur. Chlordane concentrations in two of the four sediment cores showed a peak below the sediment surface, suggesting reduced chlordane inputs in recent years. The lack of a chlordane concentration maximum below the sediment surface in the other two cores, coupled with the lack of a well-defined 137Cs peak, indicated significant sediment mixing. Simulations of 137Cs and 210Pb profiles in sediment cores with a simple sediment-mixing model were used to constrain both the deposition rate and the bioturbation rate of the sediment. Simulations of the chlordane profiles indicated continued chlordane input to LIS long after chlordane was phased out in the U.S. Continued chlordane input and significant sediment mixing may have contributed to the persistent chlordane concentrations in surficial sediment, which poses long-term threats to benthic organisms in LIS.

  6. 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.

  7. 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

  8. Wetlands and Aquatic Processes: A Bed Sediment Sampler for Precise Depth Profiling of Contaminant Concentrations in Aquatic Environments

    SciTech Connect

    Quinn, Nigel W. T.; Clyde, John R.

    1997-11-01

    A bed sediment and detritus sampler has been dec eloped for use in aquatic environments, such as in canals, rivers or lakes, for determining precise depth profiles of contaminants, The device is superior to currently available commercial push-tube and piston samplers in its simplicity, ease of use and its ability to retrieve and extrude sample cores. The sampler has been used with success during the past 12 mo to determine a profile of bed sediment Se concentrations within an earth-lined canal, alternatively used for conveyance of agricultural drainage and wetland water supply.

  9. 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.

  10. 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

  11. Multiple stress-time profiles in a RDX/AP/Al/HTPB plastic bonded explosive

    NASA Astrophysics Data System (ADS)

    Sutherland, G. T.; Forbes, J. W.; Lemar, E. R.; Ashwell, K. D.; Baker, R. N.

    1994-07-01

    PBXN-111 samples were shocked using light-gas guns. Six experiments were instrumented with in situ manganin or ytterbium gauges. Two experiments were instrumented with a rear surface quartz gauge. A linear relationship between shock velocity and particle velocity was obtained for stresses to 42 kbar. These results are compared with those from a wedge test study. Experimental stress-time profiles suggest a low level reaction occurs behind the shock front for stresses above about 16 kbar.

  12. Two-dimensional spatial resolution of concentration profiles in catalytic reactors by planar laser-induced fluorescence: NO reduction over diesel oxidation catalysts.

    PubMed

    Zellner, Alexander; Suntz, Rainer; Deutschmann, Olaf

    2015-02-23

    Planar laser-induced fluorescence (PLIF) enables noninvasive in situ investigations of catalytic flow reactors. The method is based on the selective detection of two-dimensional absolute concentration maps of conversion-relevant species in the surrounding gas phase inside a catalytic channel. Exemplarily, the catalytic reduction of NO with hydrogen (2 NO+5 H2 →2 H2 O+2 NH3 ) is investigated over a Pt/Al2 O3 coated diesel oxidation catalyst by NO PLIF inside an optically accessible channel reactor. Quenching-corrected 2D concentration maps of the NO fluorescence above the catalytic surface are obtained under both, nonreactive and reactive conditions. The impact of varying feed concentration, temperature, and flow velocities on NO concentration profiles are investigated in steady state. The technique presented has a high potential for a better understanding of interactions of mass transfer and surface kinetics in heterogeneously catalyzed gas-phase reactions.

  13. GaAs/AlGaAs heterostructure point-contact concentrator cells

    NASA Technical Reports Server (NTRS)

    Gale, R. P.; Zavracky, P. M.; Mcclelland, R. W.; Fan, John C. C.

    1987-01-01

    Point-contact cells fabricated in silicon have recently achieved very high efficiencies. Applying this structure to GaAs is difficult as it requires both surface passivation of the GaAs and a film of GaAs with thickness less than 10 microns. The authors propose to overcome these difficulties by (1) using AlGaAs layers grown by OMCVD to act as front- and back-surface fields in order to confine the photogenerated minority carriers away from the surfaces, and (2) using the CLEFT technology to produce thin, separated films of this structure. It has been found that much of the necessary technologies have been developed and that the primary problem remaining to be solved is localized junction formation.

  14. 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.

  15. 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

  16. 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

  17. A rocket radiobeacon experiment on the electron concentration profile measurements in the bottomside of the ionosphere

    NASA Astrophysics Data System (ADS)

    Sinelnikov, V. M.; Lvova, G. P.; Guliaeva, T. L.; Pakhomov, S. V.; Glotov, A. P.

    The possibility of measuring the electron density profile in the height interval 70-110 km with a two-frequency coherent transmitter set mounted on a 'small' geophysical rocket of type M-100 is investigated. Results are presented of measurements using the phase Doppler method carried out at middle latitudes in May 1979 and February 1980. Good consistency of the profiles measured for the D and E regions of the ionosphere with those of IRI is not always obtained, even when the correct helio and geophysic conditions of the experiments are given for calculations with IRI.

  18. [Comparison of dissolution profile and plasma concentration-time profile of the thalidomide formulations made by Japanese, Mexican and British companies].

    PubMed

    Fujita, Yukiyoshi; Yamamoto, Koujirou; Aomori, Tohru; Murakami, Hirokazu; Horiuchi, Ryuya

    2008-10-01

    Thalidomide is an important advance in the treatment of multiple myeloma. In Japan thalidomide is now on the approval step for the treatment of multiple myeloma. The drug has some bothersome side effects such as defect of organogenesis, neuropathy, constipation and fatigue, but is likely more effective than standard chemotherapy and is changing multiple myeloma treatment. At this moment, Japanese patients must import the thalidomide preparations from Mexico, Britain and elsewhere, but after approval, they patients will be able to get the new Japanese thalidomide capsules. In order to determine appropriate amounts of Japanese thalidomide capsules in the treatment of multiple myeloma, we compared the dissolution profile and plasma thalidomide concentrations of Japanese and British capsules and Mexican tablets. The dissolution test was performed according to the Japanese and the United States Pharmacopoeia. The pharmacokinetic data for Japanese capsules were obtained from the clinical trial in Japanese subjects and compared with those data published for other formulations. The dissolution rate of the Japanese capsule was the fastest, followed by British and Mexican formulations. The pharmacokinetic profiles of Japanese and British capsules were similar, while the 100 mg Japanese thalidomide capsule demonstrated a 1.6-fold higher maximum plasma concentration than the 200 mg Mexican thalidomide tablet (1.7 vs. 1.1 microg/ml), greatly shortened t(max) (4.5 vs. 6.2 h), and the apparent half life was only one-third of the Mexican tablet (4.8 vs. 13.5 h). A comparison of the dissolution and the pharmacokinetic absorption profiles demonstrated a rank-order correlation. Physicians and pharmacists should be aware of the probable alteration in plasma thalidomide concentration when switching to the Japanese capsule, especially from the Mexican tablet, and should monitor clinical response carefully. PMID:18827465

  19. 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.

  20. Absolute OH concentration profiles measurements in high pressure counterflow flames by coupling LIF, PLIF, and absorption techniques

    NASA Astrophysics Data System (ADS)

    Matynia, A.; Idir, M.; Molet, J.; Roche, C.; de Persis, S.; Pillier, L.

    2012-08-01

    A high-pressure combustion chamber enclosing counterflow burners was set-up at ICARE-CNRS laboratory. It allows the stabilization of flat twin premixed flames at atmospheric and high pressure. In this study, lean and stoichiometric methane/air counterflow premixed flames were studied at various pressures (0.1 MPa to 0.7 MPa). Relative OH concentration profiles were measured by Laser Induced Fluorescence. Great care was attached to the determination of the fluorescence signal by taking into account the line broadening and deexcitation by quenching which both arise at high pressure. Subsequently, OH profiles were calibrated in concentration by laser absorption technique associated with planar laser induced fluorescence. Results are successfully compared with literature. The good quality of the results attests of the experimental set-up ability to allow the study of flame structure at high pressure.

  1. 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.

  2. 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.

  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. 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.

  5. Oxygen depth profiling by resonant backscattering and glow discharge optical emission spectroscopy of Ti-6Al-4V alloy oxidized by ion implantation and plasma based treatment

    NASA Astrophysics Data System (ADS)

    Nsengiyumva, S.; Topic, M.; Pichon, L.; Comrie, C. M.; Mtshali, C.

    2016-10-01

    Oxygen depth profiling by means of 16O(α,α)16O backscattering and glow discharge optical emission spectroscopy (GDOES) was investigated in two different sets of Ti-6Al-4V samples. The first set was made of Ti-6Al-4V samples implanted at room temperature and 550 °C with 50 and 150 keV O+ ions at fluences ranging from 1.5 × 1017 to 6.0 × 1017 ions/cm2. The second set consisted of Ti-6Al-4V samples treated at 550 °C for 7 h and 24 h under low pressure (8 Pa) oxygen, eventually with RF plasma activation. These results are part of a wider investigation on Ti-6Al-4V motivated by recent publications which have shown that an oxide layer can enhance hydrogen absorption and can then promote Ti-6Al-4V alloys as efficient hydrogen storage materials. The results obtained by the two characterization techniques were compared and discussed, enabling to adjust the dependence to the oxygen concentration of the sputtering rates to be used in the time-to-depth transformation required in GDOES analysis. Considering the low thickness of oxidized alloy, usual procedures employed in GDOES depth calculation were indeed not adapted. Once calibrated thanks to the resonant RBS, GDOES can then be easily employed as fast characterization of oxidized and/or hydrogenated surface of Ti-6Al-4V. The obtained results show that the oxygen content into the surface oxidized layer slightly increases in samples implanted at higher fluence and higher temperature. However the overall oxidized layer thickness (<200 nm) remains within the projected ion depth range and is not significantly increased by thermal diffusion at 550 °C. Taken into account the initial oxide layer, the incorporated oxygen quantity mainly corresponds to the implanted fluence but it can be slightly higher with 550 °C implantation, indicating a slight additional oxidation by residual oxygen or surface contamination. The oxygen penetrations and contents in samples oxidized by thermally activated diffusion treatments were more

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    The capacitance-voltage-temperature characteristics of nonintentionally doped In0.16Al0.84N/n+-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-Va 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 1018 cm-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-Va 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.

  7. 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.

  8. 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

  9. Reply to the comment by L.-O. Öhman on "speciation of aqueous mononuclear" Al(III)-hydroxo and other Al(III) complexes at concentrations of geochemical relevance by aluminum-27 nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Faust, Bruce C.; Labiosa, William B.; Dai, K'O. H.; MacFall, Janet S.; Browne, Bryant A.; Ribeiro, Anthony A.; Richter, Daniel D.

    1997-08-01

    To summarize, it is important to recognize that (1) the major objective of our GCA paper (Faust et al., 1995) was on the development of 27Al NMR spectroscopy for characterizing mononuclear Al (III) species at concentrations of geochemical relevance; (2) Öhman has only minor comments related to this major objective; and (3) these comments are rebutted above in section 1. We appreciate Öhman's suggestion to consider adsorption of Al(III) onto the Teflon NMR sample bottle. Indeed, a small but significant percentage of Al(III) was adsorbed to the surfaces of the Teflon NMR sample bottle under the conditions of our experiments, partially accounting for the decrease in total concentration of mononuclear Al(III) species that was detected by 27Al NMR spectroscopy. As noted above in section 1, since the 27Al NMR spectroscopic parameters are not affected by decreases in total concentration of mononuclear Al(III) species, this does not affect the interpretation of the 27Al NMR chemical shifts or linewidths.

  10. 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

  11. 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

  12. 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

  13. 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.

  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. 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.

  16. [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.

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. 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).

  2. 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.

  3. Effect of feeding linseed oil in diets differing in forage to concentrate ratio: 2. Milk lactone profile.

    PubMed

    Saliba, Leacady; Gervais, Rachel; Lebeuf, Yolaine; Vuillemard, Jean-Christophe; Fortin, Jacinthe; Chouinard, P Yvan

    2014-02-01

    Lactones are important contributors to the flavour and aroma of milk and dairy products. This study was conducted to evaluate the effects of dietary linseed oil (LO) and forage to concentrate ratio on milk lactone profile. Twenty four Holstein cows were used during a 4-week feeding trial in a randomised complete block design. Cows were fed diets containing 30% (LC) or 70% (HC) concentrate, and 0% (NLO) or 3% LO in a 2×2 factorial arrangement of treatments. Milk lactone profile was evaluated using the solid phase microextraction technique. The highest levels of δ-lactones (δ-6:0, δ-8:0, δ-10:0, and δ-12:0) were found with the LC/NLO diet. These concentrations were then decreased when cows received either a high level of concentrate or supplemental LO, but these effects were not additive (interaction of LO by concentrate, P<0·01). An interaction of LO by concentrate (P<0·01) was also noted on milk γ-12:0 for which the highest concentration was observed when supplementing LO in HC diet, while no effect was apparent when LO was added in LC diet. Moreover, feeding HC increased the level of γ-12:1 in milk as compared with LC, while LO had no effect on this γ-lactone. Finally, γ-12:2 was not detected in any of the milk samples studied. Organoleptic properties of milk were evaluated in a triangle test showing that a significant number of assessors perceived a difference between milk from cows fed LC/NLO as compared with milk from cows fed HC/LO. The sensory evaluation was completed by a ranking test where the intensities of fresh lactic, foreign and global flavours were not different between treatments. In conclusion, feeding LO in HC diet modified milk lactone profile with a shift toward more γ- and less δ-lactones as compared with LC diet not supplemented with LO. A difference was perceived in a triangle test between milk from these two treatments, but the sensory attributes responsible for this difference have not been identified in the current trial.

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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

  9. Loss of body weight and fat and improved lipid profiles in obese rats fed apple pomace or apple juice concentrate.

    PubMed

    Cho, Kyung-Dong; Han, Chan-Kyu; Lee, Bog-Hieu

    2013-09-01

    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.

  10. 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.

  11. Estimating regional methane emissions from agriculture using aircraft measurements of concentration profiles

    NASA Astrophysics Data System (ADS)

    Wratt, D. S.; Gimson, N. R.; Brailsford, G. W.; Lassey, K. R.; Bromley, A. M.; Bell, M. J.

    This paper describes a "top-down" approach for estimating regional surface fluxes of methane, and its application to a pastoral farming region in New Zealand. The approach is based on air sampling from aircraft and interpretation by mesoscale dispersion modelling. The goal is an independent cross-check for an agricultural region of "bottom-up" emission estimation methods like those used for inventory reporting under the United Nations Framework Convention on Climate Change (UNFCCC). The "top-down" strategy infers emissions over an agricultural region from differences between methane concentrations measured upwind and downwind of the region. The approach was trialed over the Manawatu agricultural region of New Zealand's North Island. As expected, measured concentration differences were largest at low wind speeds (2-3 m s -1 ). However, during these low wind conditions the concentration differences could not be reliably inverted to provide emission estimates, because of the complex variability in air flow caused by topography and land-sea temperature contrasts. Useful emission estimates were obtained during days with higher wind speed (about 8 m s -1), as the strong synoptic-scale flow then suppressed the development of complex local flows. The upwind-downwind concentration differences were smaller during these conditions of stronger flow, so that precision limits to concentration measurements became significant. Methane fluxes (in the range of 20-100 mg m -2 d -1) calculated under the stronger wind speed conditions were consistent with "bottom-up" estimates scaled from per-animal emission factors, enhancing confidence in the inventory-reporting methodology.

  12. Polycyclic aromatic hydrocarbons in urban street dust and surface soil: comparisons of concentration, profile, and source.

    PubMed

    Wang, De-Gao; Yang, Meng; Jia, Hong-Liang; Zhou, Lei; Li, Yi-Fan

    2009-02-01

    Street dust and surface soil samples in urban areas of Dalian, a coastal city in Liaoning Province, China, were collected and analyzed for 25 polycyclic aromatic hydrocarbons (PAHs). The concentrations, distribution, and sources of PAHs in dust and soil were determined. The concentrations of total PAHs in street dust ranged between 1890 and 17,070 ng/g (dry weight), with an average of 7460 ng/g, whereas the concentrations of total PAHs in surface soil varied greatly, from 650 to 28,900 ng/g, with a mean value of 6440 ng/g. Statistical paired t-test confirmed that total PAH concentrations have no significant difference between street dust and surface soil. Mean PAH concentrations in two type samples were much higher at industrial sites than at business/residential or garden sites. PAHs were dominated by higher molecular weight PAH (4- to 6-ring) homologues, which accounted for about 73% and 72% of total PAHs in street dust and surface soil, respectively. Principal component analysis was used in source apportionment of PAHs in dust and soil. Pyrogenic and petrogenic sources contributed 70% and 22.4% of total PAHs in street dusts, and fossil fuel (coal and petroleum) and biomass combustion accounted for 64.4% and 5.6% of total PAHs in pyrogenic sources, respectively. In surface soil, total PAHs were dominated by pyrogenic sources. The diagnostic ratios of benz[a]anthracene/chrysene confirmed that PAHs in street dust and surface soil of a Dalian urban zone might come mostly from the emission of local sources.

  13. 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

  14. 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.

  15. 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

  16. Methods for determining agent concentration profiles in agarose gel during convection-enhanced delivery.

    PubMed

    Sindhwani, Nikhil; Ivanchenko, Oleksandr; Lueshen, Eric; Prem, Komal; Linninger, Andreas A

    2011-03-01

    Convection-enhanced delivery (CED) is a promising technique to deliver large molecular weight drugs to the human brain for treatment of Parkinson's, Alzheimer's, or brain tumors. Researchers have used agarose gels to study mechanisms of agent transport in soft tissues like brain due to its similar mechanical and transport properties. However, inexpensive quantitative techniques to precisely measure achieved agent distribution in agarose gel phantoms during CED are missing. Such precise measurements of concentration distribution are needed to optimize drug delivery. An optical experimental method to accurately quantify agent concentration in agarose is presented. A novel geometry correction algorithm is used to determine real concentrations from observable light intensities captured by a digital camera. We demonstrate the technique in dye infusion experiments that provide cylindrical and spherical distributions when infusing with porous membrane and conventional single-port catheters, respectively. This optical method incorporates important parameters, such as optimum camera exposure, captured camera intensity calibration, and use of collimated light source for maximum precision. We compare experimental results with numerical solutions to the convection diffusion equation. The solutions of convection-diffusion equations in the cylindrical and spherical domains were found to match the experimental data obtained by geometry correction algorithm.

  17. 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

  18. Effects of a nonuniform vertical profile of chlorophyll concentration on remote-sensing reflectance of the ocean.

    PubMed

    Stramska, Malgorzata; Stramski, Dariusz

    2005-03-20

    Numerical simulations of radiative transfer were used to examine the effects of a nonuniform vertical profile of the inherent optical properties of the water column associated with the vertical profile of chlorophyll concentration, Chl(z), on the spectral remote-sensing reflectance, Rrs(gamma), of the ocean. Using the Gaussian function that describes the Chl(z) profile, we simulated a relatively broad range of open-ocean conditions characterized by the presence of a subsurface Chl maximum at depths greater than or equal to 20 m. The simulations for a vertically nonuniform Chl(z) were compared with reference simulations for a homogeneous ocean whose Chl was identical to the surface Chl of inhomogeneous cases. The range of values for the Gaussian parameters that produce significant differences in Rrs(gamma) (> 5%) was determined. For some vertical structures of Chl(z) considered, the magnitude of Rrs(gamma) and the blue-to-green band ratios of Rrs(gamma) differ significantly from the reference values of homogeneous ocean (> 70% in extreme cases of low surface chlorophyll of 0.02 mg m(-3) and shallow pigment maximum at 20 m). The differences are small or negligible when the nonuniform profiles are characterized by a surface Chl greater than 0.4 mg m(-3) or a depth of Chl maximum greater than 45 m (65 m in extremely clear waters with a surface Chl of 0.02 mg m(-3) or less). The comparison of modeling results with the current algorithm for retrieving the global distribution of chlorophyll from satellite imagery of ocean color suggests that strong effects of the subsurface chlorophyll maximum on reflectance at low surface chlorophyll concentrations can lead to a severalfold overestimation in the algorithm-derived surface chlorophyll. Examples of field data from the Sea of Japan and the north polar Atlantic Ocean are used to illustrate various nonuniform pigment profiles and their effect on the blue-to-green ratio of Rrs(gamma).

  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. 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

  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. Influence of nitrite and chloride concentrations on survival and hematological profiles of striped bass

    SciTech Connect

    Mazik, P.M.; Parker, N.C. ); Hinman, M.L.; Winkelmann, D.A.; Klaine, S.J.; Simco, B.A. )

    1991-03-01

    The 24-h median lethal concentration of nitrite (NO{sub 2}{sup {minus}}) for striped bass Morone saxatilis was 163 mg/L in static toxicity tests. Exogenous chloride ions increased the tolerance of the fish for NO{sub 2}{sup {minus}}; CaCl{sub 2} was more than twice as effective as NaCl. Plasma NO{sub 2}{sup {minus}}, cortisol, and methemoglobin were correlated positively with environmental NO{sub 2}{sup {minus}}. Plasma NO{sub 2}{sup {minus}} and methemoglobin were correlated negatively with environmental Cl{sup {minus}}, but cortisol was not reduced by the presence of environmental Cl{sup {minus}}. Striped bass maintained NO{sub 2}{sup {minus}} in the plasma (0-45 mg NO{sub 2}{sup {minus}}/L) at concentrations below those in the environment (0-250 mg NO{sub 2}{sup {minus}}/L). However, striped bass were sensitive to NO{sub 2}{sup {minus}} that entered the plasma; methemoglobin levels greater than 60% and plasma NO{sub 2}{sup {minus}} levels greater than 70 mg/L resulted in significant mortalities.

  3. 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).

  4. Measurement of Fuel Concentration Profile at Leading Edge of Lifted Flame with Acetone Laser-Induced Fluorescence

    NASA Astrophysics Data System (ADS)

    Hirota, Mitsutomo; Sekine, Kazushi; Hashimoto, Kouta; Saiki, Atsushi; Takahashi, Hidemi; Masuya, Goro

    This is a study of the leading-edge characteristics of a methane-air triple flame. Few experiment results are available for physical examination of such characteristics, so further experimental investigations are strongly needed to understand the stability mechanism in a mixture with a steep concentration gradient. To this end, we measured concentration profiles at the leading edge of a flame using acetone laser-induced fluorescence (acetone LIF). The results demonstrated that the lifted height of the flame changed when acetone was added to the mixture and correlated well with increased C2 radical behind the flame edge. However, the OH radical luminous intensity, measured with a spectroscope, did not change with addition of acetone. Moreover, the burning velocity obtained by the Bunsen-burner method remained constant when acetone was added to the mixture. Therefore, acetone had little influence on burning intensity. Acetone LIF can thus be employed to measure the local concentration gradient at the leading edge of a flame. The acetone LIF signals could be corrected to consider the thermal effect by using silicone oil vanishing-plane data. From the corrected acetone LIF data, the width between the lean and rich flammability limits (flammability limit width) in the flow upstream of the flame with a steep concentration gradient was clearly observed and could be quantitatively compared with the recent numerical results.

  5. Concentrations and composition profiles of benzotriazole UV stabilizers in municipal sewage sludge in China.

    PubMed

    Ruan, Ting; Liu, Runzeng; Fu, Qiang; Wang, Thanh; Wang, Yawei; Song, Shanjun; Wang, Pu; Teng, Man; Jiang, Guibin

    2012-02-21

    The environmental contamination and fate of benzotriazole UV stabilizers (BZTs) have received increasing attention due to their large production volume and wide usage in various consumer and industrial products. In the present work, 60 municipal sewage sludge samples from wastewater treatment plants (WWTPs) in 33 cities in China were collected to investigate the occurrence and distribution of 9 frequently used BZTs. The most dominant analogue was 2-[3,5-bis(1-methyl-1-phenylethyl)-2-hydroxyphenyl]benzotriazole (UV-234) at a median concentration of 116 ng/g (dry weight) and accounted on average for 27.2% of total BZTs. The abundance was successively followed by 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole (UV-329, average 24.3%), 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole (UV-326, average 22.2%), 2-(3,5-di-tert-amyl-2-hydroxyphenyl)benzotriazole (UV-328, average 17.7%), and 2-(2-hydroxy-5-methylphenyl)benzotriazole (UV-P, average 6.6%), with median concentrations of 66.8, 67.8, 57.3, and 20.6 ng/g, respectively. 5-Chloro-2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole (UV-327) and 2-(3-sec-butyl-5-tert-butyl-2-hydroxyphenyl)benzotriazole (UV-350) had low detection frequency, while 2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole (UV-320) and 2-(5-tert-butyl-2-hydroxyphenyl)benzotriazole (UV-PS) were not detectable in any sample. To our knowledge, this is the first study reporting the occurrence of UV-234, UV-329, and UV-350 in sewage sludge in China. Significant correlations were found among the BZT concentrations and also with a WWTP characteristic (daily treatment volume). Furthermore, results from degradation prediction and multimedia fate simulation based on a quantitative structure-property relationship (QSPR) model at screening level also implied that the commercial BZT chemicals and their plausible transformation products might be persistent in the environment.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Comparison of muscle fatty acid profiles and cholesterol concentrations of bison, beef cattle, elk, and chicken.

    PubMed

    Rule, D C; Broughton, K S; Shellito, S M; Maiorano, G

    2002-05-01

    The objective of this study was to compare fatty acid weight percentages and cholesterol concentrations of longissimus dorsi (LD), semitendinosus (ST), and supraspinatus (SS) muscles (n = 10 for each) of range bison (31 mo of age), feedlot-finished bison (18 mo of age), range beef cows (4 to 7 yr of age), feedlot steers (18 mo of age), free-ranging cow elk (3 to 5 yr of age), and chicken breast. Lipids were analyzed by capillary GLC. Total saturated fatty acids (SFA) were greater (P < 0.01) in range bison than in feedlot bison and were greater (P < 0.01) in SS of range beef cattle than in feedlot steers. Muscles of elk and range bison were similar (P > 0.05) in SAT. In LD, polyunsaturated fatty acids (PUFA) were highest (P < 0.01) for elk and range bison and lowest (P < 0.01) for feedlot steers within each muscle. Range bison and range beef cows had greater (P < 0.01) PUFA in LD and ST than feedlot bison or steers, respectively. Range-fed animals had higher (P < 0.01) n-3 fatty acids than feedlot-fed animals or chicken breast. Chicken breast n-6 fatty acids were greater (P < 0.01) than for muscles from bison, beef, or elk. Elk had higher (P < 0.01) n-6 fatty acids than bison or beef cattle; however, range-fed animals had higher (P < 0.01) n-6 fatty acids than feedlot-fed animals in ST. Conjugated linoleic acid (CLA, 18:2cis-9, trans-11) in LD was greatest (P < 0.01) for range beef cows (0.4%), and lowest for chicken breast and elk (mean = 0.1%). In ST, CLA was greatest (P < 0.01) for range and feedlot bison and range beef cows (mean = 0.4%) and lowest for elk and chicken breast (mean = 0.1%). Also, SS CLA was greatest (P < 0.01) for range beef cows (0.5%) and lowest for chicken breast (0.1%). Mean total fatty acid concentration (g/100 g tissue) for all muscles was highest (P < 0.01) for feedlot bison and feedlot cattle and lowest (P < 0.01) for range bison, range beef cows, elk, and chicken. Chicken breast cholesterol (mg/100 g tissue) was higher (P < 0.01) than LD

  11. 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

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. Quantification and fatty acid profiles of sulfolipids in two halophytes and a glycophyte grown under different salt concentrations.

    PubMed

    Ramani, Balasubramanian; Zorn, Holger; Papenbrock, Jutta

    2004-01-01

    This study was aimed at understanding the role of sulfolipids in salt tolerance mechanisms of the halophytes Aster tripolium L., Compositae, and Sesuvium portulacastrum L., Aizoaceae, and of the glycophyte Arabidopsis thaliana (L.) Heynh., Brassicaceae. In Aster and Sesuvium the sulfolipid contents increased significantly under salt stress conditions (517 mM or 864 mM). In Arabidopsis, changes in sulfolipid contents were not observed (NaCl up to 100 mM). The fatty acid profile of sulfoquinovosyldiacylglycerol (SQDG) in Aster was modified with increasing NaCl concentrations. LC-MS analyses of sulfolipids from Aster and Sesuvium revealed the presence of 18:3/18:3 and 16:0/18:3 molecules. Obviously, the function of sulfolipids during salt stress differs between halophytic species and between halophytes and glycophytes where sulfolipid accumulation was not observed. PMID:15666543

  17. Correlating particle deformation with water concentration profiles during latex film formation: reasons that softer latex films take longer to dry.

    PubMed

    Carter, Farai T; Kowalczyk, Radoslaw M; Millichamp, Ian; Chainey, Malcolm; Keddie, Joseph L

    2014-08-19

    During the past two decades, an improved understanding of the operative particle deformation mechanisms during latex film formation has been gained. For a particular colloidal dispersion, the Routh-Russel deformation maps predict the dominant mechanism for particle deformation under a particular set of conditions (evaporation rate, temperature, and initial film thickness). Although qualitative tests of the Routh-Russel model have been reported previously, a systematic study of the relationship between the film-formation conditions and the resulting water concentration profiles is lacking. Here, the water distributions during the film formation of a series of acrylic copolymer latexes with varying glass-transition temperatures, Tg (values of -22, -11, 4, and 19 °C), have been obtained using GARField nuclear magnetic resonance profiling. A significant reduction in the rate of water loss from the latex copolymer with the lowest Tg was found, which is explained by its relatively low polymer viscosity enabling the growth of a coalesced skin layer. The set of processing parameters where the drying first becomes impeded occurs at the boundary between the capillary deformation and the wet sintering regimes of the Routh-Russel model, which provides strong confirmation of the model's validity. An inverse correlation between the model's dimensionless control parameter and the dimensionless drying time is discovered, which is useful for the design of fast-drying waterborne films.

  18. 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

  19. Comparative study of Al(x)Ga(1-x)As/GaAs photocathodes with different aluminum concentrations by surface photovoltage spectroscopy.

    PubMed

    Jiao, GangCheng; Hu, Canglu; Liu, Jian; Qian, Yunsheng

    2015-10-01

    The influence of aluminum concentration in an Al(x)Ga(1-x)As window layer on the performance of Al(x)Ga(1-x)As/GaAs photocathodes was investigated. Three types of transmission-mode photocathode materials with different aluminum concentrations were designed for the comparative research. The surface photovoltage technique was applied to prepare samples. After the Cs-O activation process, spectral response curves of Al(x)Ga(1-x)As/GaAs photocathodes were obtained. Comparative studies show that a higher aluminum composition in the window layer is beneficial to improve the response of Al(x)Ga(1-x)As/GaAs photocathodes in the shortwave region. The surface photovoltage calculation formula of photocathode materials was put forward and used to obtain key performance parameters of Al(x)Ga(1-x)As/GaAs photocathodes by fitting calculations. Through calculations, the Al(x)Ga(1-x)As/GaAs interface recombination velocity, the minority carrier diffusion length of the window layer, and the emission layer were deduced, and there is a positive correlation between the aluminum composition in the window layer and the Al(x)Ga(1-x)As/GaAs interface recombination velocity, which is negative with the performance of photocathodes.

  20. 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

  1. 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

  2. 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.

  3. 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

    2015-09-14

    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.

  4. 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

  5. Depth-dependent Concentrations of Cosmogenic 10Be, 26Al, 36Cl, HEc, NEc, and ARc in the Old Woman Iron Meteorite

    NASA Astrophysics Data System (ADS)

    Lavielle, B.; Nishiizumi, K.; Marti, K.; Jeannot, J.-P.; Caffee, M. W.; Finkel, R. C.

    1995-09-01

    We report measurements of 1OBe7 26AI, 36CI, and of light noble gases in 6 samples of the type IIB Old Woman iron meteorite. The aim of this work is to study the depth dependence of the production rates of cosmogenic nuclides in iron meteorites. Old Woman is a large single mass of 2753 kg. Five samples have been taken from a slice of about 100 cm x 50 cm. One other sample was located roughly 40 cm above the center of the slice in a perpendicular direction. The distances between any two samples vary from 36.5 cm to 57.5 cm. Studies of cosmogenic nuclides in samples of known locations are very useful for the validation of models describing the production of cosmogenic nuclides in meteorites. Cosmogenic radionuclides were measured by accelerator mass spectrometry at Lawrence Livermore National Laboratory. Partial results have been reported earlier [1]. Concentrations of 4He, 21Ne and 38Ar in aliquots of the samples were determined by conventional mass spectrometry using an isotopic dilution method. The ratio 3He/4He appears to be almost constant with a value of 0.12 - ().13. This is about half the value generally observed in iron meteorites. Similar low ratios have been previously observed in some irons and in chondritic metal and reflect diffusion losses of 3H 12,31. The ratios 4He/38Ar, 4He/21Ne and 36Ar/38Ar are similar to those observed in iron meteorites indicating no significant losses of 4He. The measured ratio S = 4He/21Ne which represents one of the best indicators of shielding depth in iron meteorites, varies from 310 to 375 in samples from the slice. By using this as a shielding parameter, profiles were obtained for the different nuclides investigated in this work. Systematic decreases from the surface to the center of the meteorite are observed and the center of the meteoroid can be determined. As expected from nuclear systematics, the ratio 36Cl/36Ar is almost constant. The ratio 36Cl/10Be is relatively constant with a mean value of 4.7 indicating that the

  6. 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.

  7. Observation of a linear dependence of the frequency splitting between GaAs and AlAs optical surface phonons as a function of Al concentration in AlxGa1-xAs

    NASA Astrophysics Data System (ADS)

    Guyaux, J.-L.; Thiry, P. A.; Sporken, R.; Caudano, R.; Lambin, Ph.

    1993-08-01

    In this paper, we report on the high-resolution electron-energy-loss spectroscopy study of high-quality AlxGa1-xAs ternary alloys in the whole range of Al concentration, from x=0 to 1. The ternary alloys have been grown by molecular-beam epitaxy and analyzed in the same ultrahigh-vacuum (UHV) environment. For intermediate Al concentrations we observe two long-wavelength surface phonons which can be associated with the vibrations of Ga or Al atoms against As atoms, respectively. Precise values of the frequencies of these two modes versus the Al concentration are deduced from a semitheoretical fit of the spectra and compared with the theoretical model based on the coherent-potential approximation. The surface-phonon frequency splitting provides an alternative way of determining the aluminum concentration in such ternary alloys. The intensities of both losses are considered in the framework of the dielectric theory and some conclusions are drawn for the oscillator strengths of the two surface modes.

  8. 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.

  9. 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.

  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. Comparison of STOIC 1989 ground-based lidar, microwave spectrometer, and Dobson spectrophotometer Umkehr ozone profiles with ozone profiles from balloon-borne electrochemical concentration cell ozonesondes

    NASA Astrophysics Data System (ADS)

    Komhyr, W. D.; Connor, B. J.; McDermid, I. S.; McGee, T. J.; Parrish, A. D.; Margitan, J. J.

    1995-05-01

    Ground-based measurements of stratospheric ozone using a Jet Propulsion Laboratory (JPL) lidar, a NASA Goddard Space Flight Center (GSFC) lidar, a Millitech Corporation/NASA Langley Research Center (Millitech/LaRC) microwave spectrometer, and a NOAA Dobson ozone spectrophotometer were compared with in situ measurements made quasi-simultaneously with balloon-borne electrochemical concentration cell (ECC) ozonesondes during 10 days of the Stratospheric Ozone Intercomparison Campaign (STOIC). The campaign was conducted at Table Mountain Observatory, California, during the summer of 1989. ECC ozonesondes were flown by NOAA Climate Monitoring and Diagnostics Laboratory (CMDL) personnel as well as by personnel from the NASA Wallops Island Flight Facility (WFF). Within the altitude range of 20-32 km, ozone measurement precisions were estimated to be ±0.6 to ±1.2% for the JPL lidar, ±0.7% for the GSFC lidar, ±4% for the microwave spectrometer, and ±3% for the NOAA ECC ozonesonde instruments. These precisions decreased in the 32 to 38.6-km altitude range to ±1.3, ±1.5, and ±3% to ±10% for the JPL lidar, GSFC lidar, and the ECC sondes, respectively, but remained at ±4% for the microwave instrument. Ozone measurement accuracies in the 20 to 32 km altitude range were estimated to be ±1.2 to ±2.4% for the JPL lidar, ±1.4% for the GSFC lidar, ±6% for the microwave radiometer, and ±5% for the ECC ozonesondes. The accuracies decreased in the 32 to 38.6-km altitude range to ±2.6, ±3.0, ±7, and 1 ± 4% to -4 ± 10% for the JPL lidar, the GSFC lidar, the microwave spectrometer, and the ECC ozonesondes, respectively. While accuracy estimates for the ECC sondes were obtained by combining random and estimated bias errors, the accuracies for the lidar instruments were obtained by doubling the measurement precision figures, with the assumption that such doubling accounts for systematic errors. Within the altitude range of 20-36 km the mean ozone profiles produced by the

  12. 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.

    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.

  13. Urinary arsenic speciation profiles in mice subchronically exposed to low concentrations of sodium arsenate in drinking water.

    PubMed

    Wu, Huijie; Krishnamohan, Manonmanii; Lam, Paul Kwan Sing; Ng, Jack Chakmeng

    2011-09-01

    Arsenic is a proven human carcinogen. Although the mechanism of its carcinogenicity is still largely unknown, methylation is thought to have an important role to play in arsenic toxicity. In this study, urinary methylation profiles were investigated in female C57BL/6J black mice given drinking water containing 500 μg arsenate (As(V))/L, 250 μg As(V)/L, or 100 μg As(V)/L as sodium arsenate for 2 months. The concentrations of arsenic chosen reflected those in the drinking water often encountered in arsenic-endemic areas. Urine samples were collected from the mice at the end of the exposure period, and the arsenic species were analyzed by high performance liquid chromatography-inductively coupled plasma-mass spectrometry. All detectable arsenic species showed strong linear correlation with the administered dosage. The methylation patterns were similar in all three groups with a slight decrease of dimethylarsinic acid/As(V) ratio in the 500-μg/L group, which corresponded to the significantly higher arsenic retention in the tissue. The results indicate that urinary arsenic could be used as a good biomarker for internal dose and potential biological effects. Different doses of arsenic exposure could result in different degrees of methylation, excretion, and tissue retention, and this may contribute to the understanding of arsenic carcinogenicity.

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    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 overline{3} c - Pm overline{3} 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 overline{3} c - Immb( C2/ m) - I4/ mcm was detected.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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:

  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. 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.

  2. 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.

  3. 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.

  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.

    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.

  5. 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.

  6. 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

    2016-03-29

    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).

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

    PubMed Central

    Havas, Magda; Likens, Gene E.

    1985-01-01

    The effects of aluminum (Al) on sodium (Na) regulation by the freshwater crustacean Daphnia magna were determined. 22Na 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+) at pH 5.0, and reduced the rate of morbidity at pH 4.5. Both H+ and total Al concentrations interfered with Na regulation, although it was possible to distinguish between their respective effects by using 22Na. At pH 6.5, Al decreased 22Na influx (by 46%) and increased 22Na outflux (by 25%), which led to a net loss of Na. At pH 5.0, Al reduced 22Na influx (by 58%) but had no additional effect to that of H+ on 22Na outflux. At pH 4.5, 22Na influx was significantly inhibited (by 73%) compared with the reference pH 6.5 treatment even in the absence of Al. Aluminum decreased 22Na 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 22Na 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 22Na may be due to either increased membrane permeability or increased renal losses (or both). At pH 4.5, the reduced outflux of 22Na resembles the amelioration that occurs in the presence of elevated Ca concentrations. PMID:16593623

  8. Spatial density profile of electrons near the LaAlO{sub 3}/SrTiO{sub 3} heterointerface revealed by time-resolved photoluminescence spectroscopy

    SciTech Connect

    Yamada, Yasuhiro Kanemitsu, Yoshihiko; Sato, Hiroki K.; Hikita, Yasuyuki; Hwang, Harold Y.

    2014-04-14

    The depth profile of the electron density near the LaAlO{sub 3}/SrTiO{sub 3} heterointerface has been studied by means of time-resolved photoluminescence (PL) spectroscopy. A broad blue PL band is observed at 2.9 eV, originating from the two-carrier radiative recombination of interface-induced electrons and photoexcited holes. The PL lifetime of LaAlO{sub 3}/SrTiO{sub 3} heterointerface is dominated by the three-carrier Auger recombination of electrons and holes and is sensitive to electron density. We tuned the probing depth by changing the excitation photon energy and evaluated the carrier-density profile using the relation between the carrier density and the PL lifetime. Our non-contact probe method based on PL spectroscopy indicates that the carriers are confined within several nanometers in depth near the LaAlO{sub 3}/SrTiO{sub 3} heterostructures.

  9. 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.

  10. 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

  11. Key players in neurodegenerative disorders in focus-New insights into the proteomic profile of Alzheimer's disease, schizophrenia, ALS, and multiple sclerosis-24th HUPO BPP Workshop: September 29, 2015, Vancouver, Canada.

    PubMed

    Schrötter, Andreas; Park, Young Mok; Marcus, Katrin; Martins-de-Souza, Daniel; Nilsson, Peter; Magraoui, Fouzi El; Meyer, Helmut E; Grinberg, Lea T

    2016-04-01

    The HUPO Brain Proteome Project (HUPO BPP) held its 24th workshop in Vancouver, Canada, September 29, 2015. The focus of the autumn workshop was on new insights into the proteomic profile of Alzheimer's disease, schizophrenia, ALS and multiple sclerosis.

  12. A direct detection 1.6μm DIAL with three wavelengths for high accuracy measurements of vertical CO2 concentration and temperature profiles

    NASA Astrophysics Data System (ADS)

    Shibata, Yasukuni; Nagasawa, Chikao; Abo, Makoto

    2013-10-01

    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. Moreover, wind information is an important parameter for transport simulations and inverse estimation of surface CO2 flux. A differential absorption lidar (DIAL) is an attractive method for obtaining vertical CO2 profiles and we have developed an 1.6μm DIAL system to perform simultaneous measurements of CO2 concentration, atmospheric temperature profile and wind profile. The absorption cross sections of gas and air density depends on atmospheric temperature and pressure. Then precise temperature and pressure profiles are necessary for accurate CO2 mixing ratio measurement by DIAL. Laser beams of three wavelengths around a CO2 absorption line are transmitted alternately to the atmosphere for simultaneous measurements of CO2 concentration and temperature. The receiving optics include the near-infrared photomultiplier tube and a fiber Bragg grating (FBG) filter to detect a Doppler shift.

  13. 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.

  14. 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.

  15. 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.

  16. Free energy profiles of Al3+ and La3+ cation distribution in silica and soda silicate glasses

    SciTech Connect

    Corrales, Louis R.

    2005-03-01

    The factors that control the distribution of Al3+ and La3+ cations in silica and soda silicate glasses is examined by using molecular dynamics (MD) simulations. In particular, the response of the glass network to the presence of metal oxide is probed using liquid state theory that treats the glass network as a solvent and the metal cation as a solute. MD simulations are used to obtain the mean force of the solvent-solute and solute-solute interactions along a trajectory that is then used to obtain the potential of mean force. The resulting free energy is analyzed along the trajectory to determine the stable configurations of the cation pair. Details of determining the PMF for an Al cation pair in silica and silicate glass is presented. A comparison of these results with those previously calculated for a La cation pair in the same glass systems is given. The results reveal that there are distinct differences on how the network accommodates the two different size cations. It is found that the network wraps itself around the larger La cation very much like a solvent shell, whereas, the smaller Al cation is incorporated into the network backbone. In silica and soda silicate glasses clustering of the La ion pair to form La-O-La linkages is favored, in contrast, the glasses favor a separated state of the Al ion pair.

  17. Validation of the concentration profiles obtained from the near infrared/multivariate curve resolution monitoring of reactions of epoxy resins using high performance liquid chromatography as a reference method.

    PubMed

    Garrido, M; Larrechi, M S; Rius, F X

    2007-03-01

    This paper reports the validation of the results obtained by combining near infrared spectroscopy and multivariate curve resolution-alternating least squares (MCR-ALS) and using high performance liquid chromatography as a reference method, for the model reaction of phenylglycidylether (PGE) and aniline. The results are obtained as concentration profiles over the reaction time. The trueness of the proposed method has been evaluated in terms of lack of bias. The joint test for the intercept and the slope showed that there were no significant differences between the profiles calculated spectroscopically and the ones obtained experimentally by means of the chromatographic reference method at an overall level of confidence of 5%. The uncertainty of the results was estimated by using information derived from the process of assessment of trueness. Such operational aspects as the cost and availability of instrumentation and the length and cost of the analysis were evaluated. The method proposed is a good way of monitoring the reactions of epoxy resins, and it adequately shows how the species concentration varies over time.

  18. Hume-Rothery stabilization mechanism and e/a determination in MI-type Al-Mn, Al-Re, Al-Re-Si, Al-Cu-Fe-Si and Al-Cu-Ru-Si 1/1-1/1-1/1 approximants - a proposal for a new Hume-Rothery electron concentration rule

    NASA Astrophysics Data System (ADS)

    Mizutani, U.; Inukai, M.; Sato, H.; Zijlstra, E. S.

    2012-05-01

    Full-potential linearized augmented plane wave (FLAPW) band calculations with subsequent FLAPW-Fourier analyses have been performed for five MI-type Al-TM (transition metal)-based 1/1-1/1-1/1 approximants in order to elucidate the origin of a pseudogap from the point of view of the Fermi surface-Brillouin zone (FsBz) interactions. The square of the Fermi diameter ? is determined from the Hume-Rothery plot to be close to 50 without exception in units of ? , where ? is the lattice constant. The FsBz interactions involving several reciprocal lattice vectors are claimed to be responsible for constituting the pseudogap structure across E F. This is referred to as the multi-zone effect. Among them, the ? wave, in which the Fourier coefficients are most evenly and densely distributed across E F, is selected as the critical one satisfying the matching condition ? . The d-states-mediated-splitting appears to be absent in spite of substantial occupations of TM-d states in the valence band. All MI-type approximants studied are found to obey the Hume-Rothery stabilization mechanism. A new Hume-Rothery electron concentration rule linking the number of atoms per unit cell, e/uc, with a critical reciprocal lattice vector ? is found to hold well for structurally complex intermetallic compounds obeying the Hume-Rothery stabilization mechanism.

  19. Effect of zirconium concentration on high temperature cyclic oxidation behavior of Fe-15Cr-4Al at 1150/sup 0/C

    SciTech Connect

    Pandey, J.L.; Prakash, S.; Mehta, M.L.

    1988-01-01

    The effect of zirconium (0.2, 0.55, and 1 weight percent) additions to the base alloy, Fe-15Cr-4Al, on cyclic oxidation at 1150/sup 0/C in air was investigated. Each cycle consisted of 1h holding at temperature followed by half an hour air cooling and every alloy was subjected to 32 cycles. The cyclic oxidation was observed to depend on the zirconium concentration. The lowest zirconium concentration (0.2%) imparted the maximum oxidation resistance. For comparison purposes a similar study was carried out for an alloy containing 1% yttrium. This alloy showed the best resistance to cyclic oxidation. SEM, EDAX, and EPMA of the cross sections of oxidized samples were carried out. The formation of nodules was observed in the scale formed on alloys containing zirconium and yttrium. EDAX of the nodules revealed them to be iron rich with small concentrations of zirconium, chromium, and aluminum.

  20. 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

  1. Velocity and concentration profiles of saline and turbidity currents flowing in a straight channel under quasi-uniform conditions

    NASA Astrophysics Data System (ADS)

    Stagnaro, M.; Bolla Pittaluga, M.

    2013-11-01

    We present a series of detailed experimental observations of saline and turbidity currents flowing in a straight channel. Experiments are performed by continuously feeding the channel with a dense mixture until a quasi-steady configuration is obtained. The flume, 12 m long, is characterized by a concrete fixed bed with a uniform slope of 0.005. Longitudinal velocity profiles are measured in ten cross sections, one meter apart, employing an Ultrasound Doppler Velocimeter Profiler. We also measure the density of the mixture using a rake of siphons sampling at different heights from the bottom in order to obtain the vertical density distributions in a cross sections where the flow already attained a quasi-uniform configuration. We performed 27 experiments changing the flow discharge, the fractional excess density, the character of the current (saline or turbidity) and the roughness of the bed in order to observe the consequences of these variations on the vertical velocity profiles and on the overall characteristics of the flow. Dimensionless velocity profiles under quasi-uniform flow conditions were obtained by scaling longitudinal velocity with its depth averaged value and the vertical coordinate with the flow thickness. They turned out to be influenced by the Reynolds number of the flow, by the relative bed roughness, and by the presence of sediment in suspension. Unexpectedly the densimetric Froude number of the current turned out to have no influence on the dimensionless velocity profiles.

  2. Velocity and concentration profiles of saline and turbidity currents flowing in a straight channel under quasi-uniform conditions

    NASA Astrophysics Data System (ADS)

    Stagnaro, M.; Bolla Pittaluga, M.

    2014-03-01

    We present a series of detailed experimental observations of saline and turbidity currents flowing in a straight channel. Experiments are performed by continuously feeding the channel with a dense mixture until a quasi-steady configuration is obtained. The flume, 12 m long, is characterized by a concrete fixed bed with a uniform slope of 0.005. Longitudinal velocity profiles are measured in ten cross sections, 1 m apart, employing an ultrasound Doppler velocity profiler. We also measure the density of the mixture using a rake of siphons sampling at different heights from the bottom in order to obtain the vertical density distributions in a cross section where the flow already attained a quasi-uniform configuration. We performed 27 experiments changing the flow discharge, the fractional excess density, the character of the current (saline or turbidity) and the roughness of the bed in order to observe the consequences of these variations on the vertical velocity profiles and on the overall characteristics of the flow. Dimensionless velocity profiles under quasi-uniform flow conditions were obtained by scaling longitudinal velocity with its depth averaged value and the vertical coordinate with the flow thickness. They turned out to be influenced by the Reynolds number of the flow, by the relative bed roughness, and by the presence of sediment in suspension. Unexpectedly, the densimetric Froude number of the current turned out to have no influence on the dimensionless velocity profiles.

  3. 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.

  4. 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

  5. Using a two site-reactive model for simulating one century changes of Zn and Pb concentration profiles in soils affected by metallurgical fallout.

    PubMed

    Mallmann, Fábio Joel Kochem; dos Santos, Danilo Rheinheimer; Cambier, Philippe; Labanowski, Jérôme; Lamy, Isabelle; Santanna, Maria Alice; Tessier, Daniel; van Oort, Folkert

    2012-03-01

    Predicting the transfer of contaminants in soils is often hampered by lacking validation of mathematical models. Here, we applied Hydrus-2D software to three agricultural soils for simulating the 1900-2005 changes of zinc and lead concentration profiles derived from industrial atmospheric deposition, to validate the tested models with plausible assumptions on past metal inputs to reach the 2005 situation. The models were set with data from previous studies on the geochemical background, estimated temporal metal deposition, and the 2005 metal distributions. Different hypotheses of chemical reactions of metals with the soil solution were examined: 100% equilibrium or partial equilibrium, parameterized following kinetic chemical extractions. Finally, a two-site model with kinetic constant values adjusted at 1% of EDTA extraction parameters satisfactory predicted changes in metal concentration profiles for two arable soils. For a grassland soil however, this model showed limited applicability by ignoring the role of earthworm activity in metal incorporation.

  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.

  7. Observing mixed layer depth, nitrate and chlorophyll concentrations in the northwestern Mediterranean: A combined satellite and NO3 profiling floats experiment

    NASA Astrophysics Data System (ADS)

    D'Ortenzio, Fabrizio; Lavigne, Hélöise; Besson, Florent; Claustre, Hervé; Coppola, Laurent; Garcia, Nicole; Laës-Huon, Agathe; Le Reste, Serge; Malardé, Damien; Migon, Christophe; Morin, Pascal; Mortier, Laurent; Poteau, Antoine; Prieur, Louis; Raimbault, Patrick; Testor, Pierre

    2014-09-01

    Two profiling floats, equipped with nitrate concentration sensors were deployed in the northwestern Mediterranean from summer 2012 to summer 2013. Satellite ocean color data were extracted to evaluate surface chlorophyll concentration at float locations. Time series of mixed layer depths and nitrate and chlorophyll concentrations were analyzed to characterize the interplay between the physical-chemical and biological dynamics in the area. Deep convection (mixed layer depth > 1000 m) was observed in January-February, although high-nitrate surface concentrations could be already observed in December. Chlorophyll increase is observed since December, although high values were observed only in March. The early nitrate availability in subsurface layers, which is likely due to the permanent cyclonic circulation of the area, appears to drive the bloom onset. The additional nitrate supply associated to the deep convection events, although strengthening the overall nitrate uptake, seems decoupled of the December increase of chlorophyll.

  8. 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.

  9. A Concise Reference to (Projected) Sérsic R1/n Quantities, Including Concentration, Profile Slopes, Petrosian Indices, and Kron Magnitudes

    NASA Astrophysics Data System (ADS)

    Graham, Alister W.; Driver, Simon P.

    Given the growing use of Sérsic's (1963, 1968) R1/n model for describing the stellar distributions in galaxies, and the lack of any single reference that provides the various associated mathematical expressions, we have endeavoured to compile such a resource here. We present the standard intensity profile, and its various guises such as the luminosity, surface-brightness, and aperture-magnitude profile. Expressions to transform the effective surface brightness into the mean effective and central surface brightness are also given, as is the expression to transform between effective radii and exponential scale-lengths. We additionally provide expressions for deriving the `concentration' of an R1/n profile, and two useful equations for the logarithmic slope of the light-profile are given. Petrosian radii and fluxes are also derived for a range of Sérsic profiles and compared with the effective radii and total flux. Similarly, expressions to obtain Kron radii and fluxes are presented as a function of the Sérsic index n and the number of effective radii sampled. Illustrative figures are provided throughout. Finally, the core-Sérsic model, consisting of an inner power-law and an outer Sérsic function, is presented.

  10. 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

  11. 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

  12. 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.

  13. Use of principal component analysis to profile temporal and spatial variations of chlorinated solvent concentration in groundwater.

    PubMed

    Lucas, L; Jauzein, M

    2008-01-01

    This work aims at evaluating spatial distribution patterns of concentration variations for chlorinated solvents in groundwater, based on principal component analysis and geographic information system (GIS) tools. The study investigates long-time series of chlorinated solvent concentrations in groundwater measured for 18 contaminated industrial sites. The characterization of contaminant plumes and delineation of pollutant sources are essential for choosing appropriate monitoring and remediation strategies, as contaminated groundwaters are characterized by complex patterns of spatial and temporal concentration variability, with wide unpredictable fluctuations over time. The present work describes the results of a new exploratory statistical method called the Variability Index Method (VIM) applied to environmental data to assess the performance of using concentration variations as molecular tracers to reveal aquifer dynamics, industrial impacts, and point sources for contamination plumes. The application of this method provides a useful assessment of controls over contaminant concentration variations as well as support for remediation techniques.

  14. 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.

  15. 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.

  16. Clinico-pathological profile of acute promyelocytic leukaemia at Al-Amal Oncology-Haematology Centre, Qatar.

    PubMed

    Ibrahim, F A; Yassin, M A; El-Ayoubi, H R; Alhiji, I A; Albinali, A S; Almansour, S M; Qafoud, F M

    2010-09-01

    This cases series describes the profile of adult patients with acute promyelocytic leukaemia (APt) at a referral hospital in Qatar. Of 34 acute myeloid leukaemia (AML) cases diagnosed, 11(32%) were classified as APt. Disseminated intravascular coagulation was common at presentation (91%). Severe thrombocytopenia was seen in 73%, leukocytosis in 55% and severe anaemia in 45%. Only 2 patients were of the classic hypergranular type. In the remaining 9 patients, 3 morphological subtypes were recognized: microgranular variant (6 patients), hyperbasophilic (2 patients) and regular nuclear outline M3r (1 patient). Translocation t(15;17) was detected in 63% of cases. APL constitutes a high proportion of AML cases in Qatar, with considerable morphological heterogeneity and a oredominance of APL variants with unfavourable oresenting features. PMID:21218723

  17. Effects of elevated atmospheric CO2 concentration and temperature on the soil profile methane distribution and diffusion in rice-wheat rotation system.

    PubMed

    Yang, Bo; Chen, Zhaozhi; Zhang, Man; Zhang, Heng; Zhang, Xuhui; Pan, Genxing; Zou, Jianwen; Xiong, Zhengqin

    2015-06-01

    The aim of this experiment was to determine the impacts of climate change on soil profile concentrations and diffusion effluxes of methane in a rice-wheat annual rotation ecosystem in Southeastern China. We initiated a field experiment with four treatments: ambient conditions (CKs), CO2 concentration elevated to ~500 μmol/mol (FACE), temperature elevated by ca. 2°C (T) and combined elevation of CO2 concentration and temperature (FACE+T). A multilevel sampling probe was designed to collect the soil gas at four different depths, namely, 7 cm, 15 cm, 30 cm and 50 cm. Methane concentrations were higher during the rice season and decreased with depth, while lower during the wheat season and increased with depth. Compared to CK, mean methane concentration was increased by 42%, 57% and 71% under the FACE, FACE+T and T treatments, respectively, at the 7 cm depth during the rice season (p<0.05). Mean methane diffusion effluxes to the 7 cm depth were positive in the rice season and negative in the wheat season, resulting in the paddy field being a source and weak sink, respectively. Moreover, mean methane diffusion effluxes in the rice season were 0.94, 1.19 and 1.42 mg C/(m2·hr) in the FACE, FACE+T and T treatments, respectively, being clearly higher than that in the CK. The results indicated that elevated atmospheric CO2 concentration and temperature could significantly increase soil profile methane concentrations and their effluxes from a rice-wheat field annual rotation ecosystem (p<0.05).

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. Polychlorinated biphenyls (PCBs) in industrial and municipal effluents: concentrations, congener profiles, and partitioning onto particulates and organic carbon.

    PubMed

    Balasubramani, Aparna; Howell, Nathan L; Rifai, Hanadi S

    2014-03-01

    Wastewater effluent samples were collected in the summer of 2009 from 16 different locations which included municipal and industrial wastewater treatment plants and petrochemical industrial outfalls in the Houston area. The effluent samples were analyzed for all 209 polychlorinated biphenyls (PCBs) congeners using high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) using the USEPA method 1668A. The total PCBs (∑209) concentration in the dissolved medium ranged from 1.01 to 8.12 ng/L and ranged from 2.03 to 31.2 ng/L in the suspended medium. Lighter PCB congeners exhibited highest concentrations in the dissolved phase whereas, in the suspended phase, heavier PCBs exhibited the highest concentrations. The PCB homolog concentrations were dominated by monochlorobiphenyls through hexachlorobiphenyls, with dichlorobiphenyls exhibiting the highest concentration amongst them at most of the effluent outfalls, in the suspended phase. Both total suspended solids (TSS) and various organic carbon fractions played an important role in the distribution of the suspended fractions of PCBs in the effluents. The log Koc values determined in the effluents suggest that effluent PCB loads might have more risk and impact than what standard partitioning models predict.

  3. Refinement of the Cornell et al. Nucleic Acids Force Field Based on Reference Quantum Chemical Calculations of Glycosidic Torsion Profiles.

    PubMed

    Zgarbová, Marie; Otyepka, Michal; Sponer, Jiří; Mládek, Arnošt; Banáš, Pavel; Cheatham, Thomas E; Jurečka, Petr

    2011-09-13

    We report a reparameterization of the glycosidic torsion χ of the Cornell et al. AMBER force field for RNA, χ(OL). The parameters remove destabilization of the anti region found in the ff99 force field and thus prevent formation of spurious ladder-like structural distortions in RNA simulations. They also improve the description of the syn region and the syn-anti balance as well as enhance MD simulations of various RNA structures. Although χ(OL) can be combined with both ff99 and ff99bsc0, we recommend the latter. We do not recommend using χ(OL) for B-DNA because it does not improve upon ff99bsc0 for canonical structures. However, it might be useful in simulations of DNA molecules containing syn nucleotides. Our parametrization is based on high-level QM calculations and differs from conventional parametrization approaches in that it incorporates some previously neglected solvation-related effects (which appear to be essential for obtaining correct anti/high-anti balance). Our χ(OL) force field is compared with several previous glycosidic torsion parametrizations.

  4. A vertical profile of PM10 dust concentrations measured during a regional dust event identified by MODIS Terra, western Queensland, Australia

    NASA Astrophysics Data System (ADS)

    McGowan, Hamish A.; Clark, Andrew

    2008-03-01

    Accurate determination of the spatiotemporal properties of dust plumes and their dust concentrations is essential for calibration of satellite products and the initialization and validation of numerical models that simulate the physical properties and affects of dust events. In this paper, we present a 500 m vertical profile of PM10 dust concentrations measured during a regional dust event in western Queensland, Australia. PM10 dust concentrations within the haze were found to be >20 times background ambient values and decreased with height following an exponential function. We apply an over-land algorithm to MODIS Terra satellite images of the dust haze to enhance its visual appearance against the bright land surface and define its size. In conjunction with the measured attenuation of dust concentrations with height we calculate the PM10 dust load of the plume to be ~60% of that which would have been calculated assuming a constant dust concentration up to the dust ceiling height. Results extend previous findings from tower-based studies made close to the surface and confirm that atmospheric dust concentrations decrease rapidly with increasing height, thereby enabling more accurate calculation of atmospheric dust loads during synoptic-scale dust outbreaks.

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. An eccentric- and concentric-strength profile of shoulder external and internal rotator muscles in professional baseball pitchers.

    PubMed

    Sirota, S C; Malanga, G A; Eischen, J J; Laskowski, E R

    1997-01-01

    The purpose of this study was to establish a data base on the isokinetic eccentric muscular performance characteristics of external and internal rotator muscles in the shoulders of professional baseball pitchers. Concentric data are also included and compared with previously published concentric studies. Twenty-five professional baseball pitchers were evaluated with a Kin-Com isokinetic dynamometer. The subjects tested had a mean age of 23.5 years and a mean body weight of 199 pounds. Eccentric and concentric isokinetic tests were performed at 60 and 120 deg/sec. The testing protocol was standardized for each subject. Test results indicated no statistically significant difference in mean torque between throwing and nonthrowing shoulders for either external or internal rotator muscle groups. Eccentric strength was significantly greater than concentric strength for all muscle groups tested. The external-to-internal rotator muscle strength ratios were well above those previously published for high school through professional pitchers. Mean torque-to-lean body weight ratios were also included to establish a data base. This study establishes one of the first data bases for eccentric isokinetic muscle strength of shoulder rotator muscles in professional baseball pitchers. The data may help clinicians prevent and rehabilitate shoulder injuries in professional throwing athletes.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. Homeostasis and Cancer Symptom in Elemental Concentration Profiles of Hair Observed by Fluorescent X-ray Analysis with Synchrotron Radiation

    NASA Astrophysics Data System (ADS)

    Chikawa, Jun-ichi

    2004-08-01

    Hair samples of 37 donors including 12 patients of hepatocelluar carcinoma have been examined by fluorescent X-ray analysis using the SPring-8, which detected many kinds of trace elements in a single hair root. Homeostasis in concentrations of Ca, Fe, Cu, Zn and Sr was found to be in consistency with their concentrations measured for the serum in a healthy case. Unusual increases of [Cu] and/or [Fe] were observed for hair of the patients by disorder of the liver function to excrete these elements due to cancer. The unique behavior observed for [Ca] is discussed in relation to the "Calcium paradox", a phenomenon of increasing from the regulated Ca ion concentration in cytosol, which is caused by parathyroid hormone in the case of Ca deficiency due to many kinds of disease as well as insufficient intake and absorption of Ca. It is concluded that the analysis of hair is useful for screening serious diseases such as the cancer and osteoporosis.

  15. 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.

  16. PAPERS DEVOTED TO THE 250TH ANNIVERSARY OF THE MOSCOW STATE UNIVERSITY: Monte Carlo simulation of an optical coherence Doppler tomograph signal: the effect of the concentration of particles in a flow on the reconstructed velocity profile

    NASA Astrophysics Data System (ADS)

    Bykov, A. V.; Kirillin, M. Yu; Priezzhev, A. V.

    2005-02-01

    Model signals of an optical coherence Doppler tomograph (OCDT) are obtained by the Monte Carlo method from a flow of a light-scattering suspension of lipid vesicles (intralipid) at concentrations from 0.7% to 1.5% with an a priori specified parabolic velocity profile. The velocity profile parameters reconstructed from the OCDT signal and scattering orders of the photons contributing to the signal are studied as functions of the suspension concentration. It is shown that the maximum of the reconstructed velocity profile at high concentrations shifts with respect to the symmetry axis of the flow and its value decreases due to a greater contribution from multiply scattered photons.

  17. Polychlorinated biphenyl concentrations, congener profiles, and ratios in the fat tissue, eggs, and plasma of snapping turtles (Chelydra s. serpentina) from the Ohio Basin of Lake Erie, USA.

    PubMed

    Dabrowska, H; Fisher, S W; Estenik, J; Kidekhel, R; Stromberg, P

    2006-08-01

    Concentrations and profiles of polychlorinated biphenyls (PCBs) were determined in three tissues of adult snapping turtles (Chelydra serpentina serpentina) from six locations in the Ohio Basin of Lake Erie to characterize tissue variation and geographic trends. The locations included the Ohio Areas of Concern, i.e., the Ashtabula, Black, and Maumee Rivers; the Ottawa River near Toledo; and two reference sites. Mean total PCBs were greatest in turtles from the Ottawa River followed by the Maumee, Ashtabula, and Black Rivers. All three types of samples-fat tissue (FT), eggs, and plasma-showed the same geographic trend in PCB levels. On a wet-weight basis, mean concentrations ranged from 2,148 to 18,669 ng/g in FT, from 183 to 3,683 ng/g in eggs, and from 18 to 201 ng/g in plasma. Across all sites, total PCB concentrations between the tissues were significantly correlated (0.001 < p < 0.005; Pearson correlation coefficient (r ( P )) was between 0.720 and 0.954). Two distinctly different profiles with respect to relative congener and homologue concentrations were found among the sites. One that included four of the six sites examined was characterized by hexa-chlorobiphenyl (hexa-CB) dominance followed by hepta-CBs, with PCBs no. 138 + 163, 153 + 132 + 105, and 180 being the most abundant congeners. The second profile, specific for turtles from the Ottawa River, was different from the first in that tetra-CBs were the most abundant congeners followed by hexa-CBs. Analysis of variance (ANOVA) indicated significant intertissue differences in the PCB homologue profiles, i.e., FT had a higher percentage of hepta-, octa-, and nona-CBs compared with eggs and plasma, whereas eggs showed a higher percentage of hexa-CBs. At any listed location, FT, eggs, and plasma had the same congener profile. An intertissue distribution of lipid-normalized individual congener concentrations examined by regression analyses revealed significant egg-FT, egg-plasma, and FT-plasma relations for

  18. 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.

  19. Measurement of gas-liquid partition coefficient and headspace concentration profiles of perfume materials by solid-phase microextraction and capillary gas chromatography-mass spectrometry

    PubMed

    Liu; Wene

    2000-09-01

    An empirical model describing the relationship between the partition coefficients (K) of perfume materials in the solid-phase microextraction (SPME) fiber stationary phase and the Linearly Temperature Programmed Retention Index (LTPRI) is obtained. This is established using a mixture of eleven selected fragrance materials spiked in mineral oil at different concentration levels to simulate liquid laundry detergent matrices. Headspace concentrations of the materials are measured using both static headspace and SPME-gas chromatography analysis. The empirical model is tested by measuring the K values for fourteen perfume materials experimentally. Three of the calculated K values are within 2-19% of the measured K value, and the other eleven calculated K values are within 22-59%. This range of deviation is understandable because a diverse mixture was used to cover most chemical functionalities in order to make the model generally applicable. Better prediction accuracy is expected when a model is established using a specific category of compounds, such as hydrocarbons or aromatics. The use of this method to estimate distribution constants of fragrance materials in liquid matrices is demonstrated. The headspace SPME using the established relationship between the gas-liquid partition coefficient and the LTPRI is applied to measure the headspace concentration of fragrances. It is demonstrated that this approach can be used to monitor the headspace perfume profiles over consumer laundry and cleaning products. This method can provide high sample throughput, reproducibility, simplicity, and accuracy for many applications for screening major fragrance materials over consumer products. The approach demonstrated here can be used to translate headspace SPME results into true static headspace concentration profiles. This translation is critical for obtaining the gas-phase composition by correcting for the inherent differential partitioning of analytes into the fiber stationary

  20. 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

  1. 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.

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. Measurement of indium concentration profiles and segregation efficiencies from high-angle annular dark field-scanning transmission electron microscopy images.

    PubMed

    Mehrtens, Thorsten; Müller, Knut; Schowalter, Marco; Hu, Dongzhi; Schaadt, Daniel M; Rosenauer, Andreas

    2013-08-01

    We investigated segregation of indium in an InxGa1-xAs/GaAs heterostructure via high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM), where contrast strongly depends on the nuclear charges of the scattering atoms (Z-contrast). Indium concentration maps have been deduced from HAADF-STEM images by comparing normalized measured intensities with multislice simulations in the frozen lattice approach. Segregation coefficients were derived following the segregation model of Muraki et al.. This is demonstrated for HAADF-STEM images recorded in [100] and [110] zone-axes. Determined indium concentrations and segregation coefficients are compared with results from composition analysis by lattice fringe analysis (CELFA) measurements and energy-dispersive X-ray analysis (EDX).

  9. 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.

  10. 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.

  11. Predicting the oxidative lifetime of beta NiAl-Zr alloys

    NASA Technical Reports Server (NTRS)

    Nesbitt, J. A.; Vinarcik, E. J.

    1991-01-01

    Nickel aluminides containing 40 to 50 at. pct Al and 0.1 at. pct Zr were studied following cyclic oxidation at 1400 C. The selective oxidation of Al resulted in the formation of protective Al2O3 scales on each alloy composition. However, repeated cycling eventually resulted in the gradual formation of less-protective NiAl2O4, first appearing on the 40Al alloys followed at longer times on the 45Al alloys. The appearance of the NiAl2O4, signaling the end of the protective scale-forming capability of the alloy, was related to the presence of gamma-prime (Ni3Al) which formed as a result of the loss of Al from the sample. A diffusion model, based on finite-difference techniques, was developed to predict the protective life of beta Ni-Al alloys. This model predicts Ni and Al concentration profiles after various oxidation exposures. The model can predict the oxidative lifetime due to Al depletion when the Al concentration decreases to a critical concentration. Measured Al concentration profiles on two alloys after various oxidation exposures are compared to those predicted by the diffusion model. The time to the appearance of the NiAl2O4 and that predicted by the diffusion model are compared and discussed.

  12. Analysis of the temperature profile of ceramic composite materials exposed to combined conduction-radiation between concentric cylinders

    SciTech Connect

    Tremante, A.; Malpica, F.

    1998-04-01

    A numerical study is made of the thermal characteristics of semitransparent materials exposed to simultaneous conduction and radiation between concentric cylinders. For extremely high-temperature applications, where radiative transfer plays an important role, ceramic-matrix composites, considered as semitransparent materials, are being explored for potential use in turbine and compressor components, spacecraft structures, engine control systems and nuclear reactors. Through the use of a gray model and the two-flux method, specialized equations are developed that generate a system of nonlinear ordinary differential equations. To facilitate the solution of this system, an iterative strategy is adopted. In order to demonstrate the versatility and accuracy of the proposed methodology, the results of several numerical experiments are presented and compared with benchmark solutions.

  13. Ultratrace determination of arsenic in water samples by electrothermal atomic absorption spectrometry after pre-concentration with Mg-Al-Fe ternary layered double hydroxide nano-sorbent.

    PubMed

    Abdolmohammad-Zadeh, Hossein; Jouyban, Abolghasem; Amini, Roghayeh

    2013-11-15

    A selective solid phase extraction method, based on nano-structured Mg-Al-Fe(NO3(-)) ternary layered double hydroxide as a sorbent, is developed for the pre-concentration of ultra-trace levels of arsenic (As) prior to determination by electrothermal atomic absorption spectrometry. It is found that both As(III) and As(V) could be quantitatively retained on the sorbent within a wide pH range of 4-12. Accordingly, the presented method is applied to determination of total inorganic As in aqueous solutions. Maximum analytical signal of As is achieved when the pyrolysis and atomization temperatures are close to 900 °C and 2300 °C, respectively. Several variables affecting the extraction efficiency including pH, sample flow rate, amount of nano-sorbent, elution conditions and sample volume are optimized. Under the optimized conditions, the limit of detection (3Sb/m) and the relative standard deviation are 4.6 pg mL(-1) and 3.9%, respectively. The calibration graph is linear in the range of 15.0-650 pg mL(-1) with a correlation coefficient of 0.9979, sorption capacity and pre-concentration factor are 8.68 mg g(-1) and 300, respectively. The developed method is validated by the analysis of a standard reference material (SRM 1643e) and is successfully applied to the determination of ultra-trace amounts of As in different water samples.

  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. 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.

  16. 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

  17. Nonlinear predictive control for the concentrations profile regulation under unknown reaction disturbances in a fuel cell anode gas channel

    NASA Astrophysics Data System (ADS)

    Luna, Julio; Ocampo-Martinez, Carlos; Serra, Maria

    2015-05-01

    In this work, a nonlinear model predictive control (NMPC) strategy is proposed to regulate the concentrations of the different gas species inside a Proton Exchange Membrane Fuel Cell (PEMFC) anode gas channel. The purpose of the regulation relies on the rejection of the unmeasurable perturbations that affect the system: the hydrogen reaction and water transport terms. The model of the anode channel is derived from the discretisation of the partial differential equations that define the nonlinear dynamics of the system, taking into account spatial variations along the channel. Forward and backward discretisations of the distributed model are employed to take advantage of the boundary conditions of the problem. A linear observer is designed and implemented to perform output-feedback control of the plant. This information is fed to the controller to regulate the states towards their desired values. Simulation results are presented to show the performance of the proposed control method over a given case study. Different cost functions are compared and the one with minimum state-regulation error is identified. Suitable dynamic responses are obtained facing the different considered disturbances.

  18. Protein profile and alpha-lactalbumin concentration in the milk of standard and transgenic goats expressing recombinant human butyrylcholinesterase.

    PubMed

    Baldassarre, H; Schirm, M; Deslauriers, J; Turcotte, C; Bordignon, V

    2009-08-01

    The expression of recombinant proteins of pharmaceutical interest in the milk of transgenic farm animals can result in phenotypes exhibiting compromised lactation performance, as a result of the extraordinary demand placed on the mammary gland. In this study, we investigated differences in the protein composition of milk from control and transgenic goats expressing recombinant human butyrylcholinesterase. In Experiment 1, the milk was characterized by gel electrophoresis and liquid chromatography/mass spectrometry in order to identify protein bands that were uniquely visible in the transgenic milk and/or at differing band densities compared with controls. Differences in protein content were additionally evaluated by computer assisted band densitometry. Proteins identified in the transgenic milk only included serum proteins (i.e. complement component 3b, ceruloplasmin), a cytoskeleton protein (i.e. actin) and a stress-induced protein (94 kDA glucose-regulated protein). Proteins exhibiting evident differences in band density between the transgenic and control groups included immunoglobulins, serum albumin, beta-lactoglobulin and alpha-lactalbumin. These results were found to be indicative of compromised epithelial tight junctions, premature mammary cell death, and protein synthesis stress resulting from transgene expression. In Experiment 2, the concentration of alpha-lactalbumin was determined using the IDRing assay and was found to be significantly reduced on day 1 of lactation in transgenic goats (4.33 +/- 0.97 vs. 2.24 +/- 0.25 mg/ml, P < 0.01), but was not different from non-transgenic controls by day 30 (0.99 +/- 0.46 vs. 0.90 +/- 0.11 mg/ml, P > 0.05). We concluded that a decreased/delayed expression of the alpha-lactalbumin gene may be the cause for the delayed start of milk production observed in this herd of transgenic goats.

  19. 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

  20. 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

  1. 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

  2. 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

  3. [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

  4. [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).

  5. 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

  6. Bio-active engineered 50 nm silica nanoparticles with bone anabolic activity: therapeutic index, effective concentration, and cytotoxicity profile in vitro.

    PubMed

    Ha, Shin-Woo; Sikorski, James A; Weitzmann, M Neale; Beck, George R

    2014-04-01

    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

  7. Haemostatic profile of reconstituted blood in a proposed 1:1:1 ratio of packed red blood cells, platelet concentrate and four different plasma preparations.

    PubMed

    Ponschab, M; Schöchl, H; Gabriel, C; Süssner, S; Cadamuro, J; Haschke-Becher, E; Gratz, J; Zipperle, J; Redl, H; Schlimp, C J

    2015-05-01

    The concept of haemostatic resuscitation implies early and high-volume plasma transfusion. We investigated the haemostatic profile of reconstituted whole blood prepared in a 1:1:1 ratio of blood, platelets and plasma. This consisted of packed red blood cells, platelet concentrate and four different plasma variants: fresh frozen; solvent-detergent; lyophilised quarantine; and lyophilised methylene blue-inactivated plasma. Haematocrit, platelet count, endogenous thrombin potential and coagulation factor activity were significantly lower in reconstituted blood compared with citrated whole blood (p < 0.01). Except for lyophilised methylene blue-inactivated plasma, no substantial differences between plasma variants in coagulation factor activity, endogenous thrombin potential and standard coagulation tests were observed. After reconstitution, haematocrit and platelet counts were slightly above recommended transfusion triggers, most thromboelastometry (ROTEM(®)) parameters were within the normal range and fibrinogen concentrations were between 1.57 g.l(-1) and 1.91 g.l(-1). Reconstitution of whole blood in a 1:1:1 ratio resulted in significant dilution of haematocrit and platelet count, but values remained above limits recommended by transfusion guidelines. Fibrinogen concentrations of reconstituted whole blood were also significantly reduced, and these were below the threshold value for supplementation recommended by recent guidelines.

  8. 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.

    2016-10-01

    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.

  9. 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.

  10. 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.

  11. Metabolic Profiling and Flux Analysis of MEL-2 Human Embryonic Stem Cells during Exponential Growth at Physiological and Atmospheric Oxygen Concentrations

    PubMed Central

    Titmarsh, Drew; Krömer, Jens O.; Kao, Li-Pin; Nielsen, Lars; Wolvetang, Ernst; Cooper-White, Justin

    2014-01-01

    As human embryonic stem cells (hESCs) steadily progress towards regenerative medicine applications there is an increasing emphasis on the development of bioreactor platforms that enable expansion of these cells to clinically relevant numbers. Surprisingly little is known about the metabolic requirements of hESCs, precluding the rational design and optimisation of such platforms. In this study, we undertook an in-depth characterisation of MEL-2 hESC metabolic behaviour during the exponential growth phase, combining metabolic profiling and flux analysis tools at physiological (hypoxic) and atmospheric (normoxic) oxygen concentrations. To overcome variability in growth profiles and the problem of closing mass balances in a complex environment, we developed protocols to accurately measure uptake and production rates of metabolites, cell density, growth rate and biomass composition, and designed a metabolic flux analysis model for estimating internal rates. hESCs are commonly considered to be highly glycolytic with inactive or immature mitochondria, however, whilst the results of this study confirmed that glycolysis is indeed highly active, we show that at least in MEL-2 hESC, it is supported by the use of oxidative phosphorylation within the mitochondria utilising carbon sources, such as glutamine to maximise ATP production. Under both conditions, glycolysis was disconnected from the mitochondria with all of the glucose being converted to lactate. No difference in the growth rates of cells cultured under physiological or atmospheric oxygen concentrations was observed nor did this cause differences in fluxes through the majority of the internal metabolic pathways associated with biogenesis. These results suggest that hESCs display the conventional Warburg effect, with high aerobic activity despite high lactate production, challenging the idea of an anaerobic metabolism with low mitochondrial activity. The results of this study provide new insight that can be used in

  12. Metabolic profiling and flux analysis of MEL-2 human embryonic stem cells during exponential growth at physiological and atmospheric oxygen concentrations.

    PubMed

    Turner, Jennifer; Quek, Lake-Ee; Titmarsh, Drew; Krömer, Jens O; Kao, Li-Pin; Nielsen, Lars; Wolvetang, Ernst; Cooper-White, Justin

    2014-01-01

    As human embryonic stem cells (hESCs) steadily progress towards regenerative medicine applications there is an increasing emphasis on the development of bioreactor platforms that enable expansion of these cells to clinically relevant numbers. Surprisingly little is known about the metabolic requirements of hESCs, precluding the rational design and optimisation of such platforms. In this study, we undertook an in-depth characterisation of MEL-2 hESC metabolic behaviour during the exponential growth phase, combining metabolic profiling and flux analysis tools at physiological (hypoxic) and atmospheric (normoxic) oxygen concentrations. To overcome variability in growth profiles and the problem of closing mass balances in a complex environment, we developed protocols to accurately measure uptake and production rates of metabolites, cell density, growth rate and biomass composition, and designed a metabolic flux analysis model for estimating internal rates. hESCs are commonly considered to be highly glycolytic with inactive or immature mitochondria, however, whilst the results of this study confirmed that glycolysis is indeed highly active, we show that at least in MEL-2 hESC, it is supported by the use of oxidative phosphorylation within the mitochondria utilising carbon sources, such as glutamine to maximise ATP production. Under both conditions, glycolysis was disconnected from the mitochondria with all of the glucose being converted to lactate. No difference in the growth rates of cells cultured under physiological or atmospheric oxygen concentrations was observed nor did this cause differences in fluxes through the majority of the internal metabolic pathways associated with biogenesis. These results suggest that hESCs display the conventional Warburg effect, with high aerobic activity despite high lactate production, challenging the idea of an anaerobic metabolism with low mitochondrial activity. The results of this study provide new insight that can be used in

  13. 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.

  14. 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.

  15. The dynamic ocean biological pump: Insights from a global compilation of particulate organic carbon, CaCO3, and opal concentration profiles from the mesopelagic

    NASA Astrophysics Data System (ADS)

    Lam, Phoebe J.; Doney, Scott C.; Bishop, James K. B.

    2011-09-01

    We have compiled a global data set of 62 open ocean profiles of particulate organic carbon (POC), CaCO3, and opal concentrations collected by large volume in situ filtration in the upper 1000 m over the last 30 years. We define concentration-based metrics for the strength (POC concentration at depth) and efficiency (attenuation of POC with depth in the mesopelagic) of the biological pump. We show that the strength and efficiency of the biological pump are dynamic and are characterized by a regime of constant and high transfer efficiency at low to moderate surface POC and a bloom regime where the height of the bloom is characterized by a weak deep biological pump and low transfer efficiency. The variability in POC attenuation length scale manifests in a clear decoupling between the strength of the shallow biological pump (e.g., POC at the export depth) and the strength of the deep biological pump (POC at 500 m). We suggest that the paradigm of diatom-driven export production is driven by a too restrictive perspective on upper mesopelagic dynamics. Indeed, our full mesopelagic analysis suggests that large, blooming diatoms have low transfer efficiency and thus may not export substantially to depth; rather, our analysis suggests that ecosystems characterized by smaller cells and moderately high %CaCO3 have a high mesopelagic transfer efficiency and can have higher POC concentrations in the deep mesopelagic even with relatively low surface or near-surface POC. This has negative implications for the carbon sequestration prospects of deliberate iron fertilization.

  16. Effect of acetylation and succinylation on solubility profile, water absorption capacity, oil absorption capacity and emulsifying properties of mucuna bean (Mucuna pruriens) protein concentrate.

    PubMed

    Lawal, O S; Adebowale, K O

    2004-04-01

    Mucuna protein concentrate was acylated with succinic and acetic anhydride. The effects of acylation on solubility, water absorption capacity, oil absorption capacity and emulsifying properties were investigated. The pH-dependent solubility profile of unmodified mucuna protein concentrate (U-mpc) showed a decrease in solubility with decrease in pH and resolubilisation at pH values acidic to isoelectric pH (pH 4). Apart from pH 2, both acetylated mucuna protein concentrates (A-mpc) and succinylated mucuna protein concentrate (S-mpc) had improved solubility over the unmodified derivative. Acylation increased the water absorption capacity (WAC) at all levels of ionic strength (0.1-1.0 M). WAC of the protein samples increased with increase in ionic strength up to 0.2 M after which a decline occurred with increase in ionic strength from 0.4-1.0 M. When protein solutions were prepared in salts of various ions, increase in WAC followed the Hofmeister series in the order: NaSCN < NaClO4 < NaI < NaBr < NaCl < Na2SO. Acetylation improved the oil absorption capacity while the lipophilic tendency reduced the following succinylation. Emulsifying capacity increased with increase in concentration up to 2, 4 and 5% w/v for U-mpc, A-mpc and S-mpc, respectively, after which an increase in concentration reduced the emulsifying capacity. Both acetylation and succinylation significantly (P < 0.05) improved the emulsifying capacity at pH 4-10. Initial increase in ionic strength up to 0.4 M for U-mpc and 0.4 M for A-mpc and S-mpc increased the emulsion capacity progressively. Further increase in ionic strength reduced emulsion capacity (EC). Contrary to the effect of various salts on WAC, increase in EC generally follows the series Na2SO4 < NaCl < NaBr < NaI < NaClO4 < NaSCN. At all levels of ionic strength studied, S-mpc had a better emulsifying activity (EA) than both A-mpc and U-mpc. EA and emulsifying stability (ES) were pH-dependent. Maximum EA and ES were recorded at pH 10. ES of

  17. 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

  18. 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

  19. Effects of oligofructose on appetite profile, glucagon-like peptide 1 and peptide YY3-36 concentrations and energy intake.

    PubMed

    Verhoef, Sanne P M; Meyer, Diederick; Westerterp, Klaas R

    2011-12-01

    In rats, oligofructose has been shown to stimulate satiety hormone secretion, reduce energy intake and promote weight loss. The present study aimed to examine the effect of oligofructose supplementation on appetite profiles, satiety hormone concentrations and energy intake in human subjects. A total of thirty-one healthy subjects (ten men and twenty-one women) aged 28 (SEM 3) years with a BMI of 24·8 (SEM 0·3) kg/m(2) were included in a randomised double-blind, cross-over study. The subjects received 10 g oligofructose, 16 g oligofructose or 16 g placebo (maltodextrin) daily for 13 d, with a 2-week washout period between treatments. Appetite profile, active glucagon-like peptide 1 (GLP-1) and peptide YY3-36 (PYY) concentrations and energy intake were assessed on days 0 and 13 of the treatment period. Time × treatment interaction revealed a trend of reduction in energy intake over days 0-13 by oligofructose (P = 0·068). Energy intake was significantly reduced (11 %) over time on day 13 compared with day 0 with 16 g/d oligofructose (2801 (SEM 301) v. 3217 (SEM 320) kJ, P < 0·05). Moreover, energy intake was significantly lower with 16 g/d oligofructose compared with 10 g/d oligofructose on day 13 (2801 (SEM 301) v. 3177 (SEM 276) kJ, P < 0·05). Area under the curve (AUC) for GLP-1 on day 13 was significantly higher with 16 g/d oligofructose compared with 10 g/d oligofructose (45 (SEM 4) v. 41 (SEM 3) pmol/l × h, P < 0·05). In the morning until lunch, AUC(0-230 min) for PYY on day 13 was significantly higher with 16 g/d oligofructose compared with 10 g/d oligofructose and placebo (409 (SEM 35) v. 222 (SEM 19) and 211 (SEM 20) pg/ml × h, P < 0·01). In conclusion, 16 g/d and not 10 g/d oligofructose may be an effective dose to reduce energy intake, possibly supported by higher GLP-1 and PYY concentrations.

  20. 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.

  1. The effect of tick infestation on the serum concentrations of the cardiac biomarker troponin I, acid-base balance and haematobiochemical profiles in camels (Camelus dromedarius).

    PubMed

    Tharwat, Mohamed; Al-Sobayil, Fahd

    2014-01-01

    The aim of the present study was to evaluate the serum concentration of cardiac troponin I (cTnI) in camels with tick infestation as a marker of potential myocardial injury and its prognostication. The effects of acid-base and electrolyte balance and haematobiochemical profiles were also investigated. Twenty-three camels (Camelus dromedarius) with tick infestation and suffering from anorexia, incoordination of movement, unsteady gait, recumbency, opisthotonus, anaemia and reduced production were examined. Ticks were visible, deeply embedded in the skin over the whole body, especially under the neck and around the udder or testis. Of the camels, 15 recovered after treatment and 8 did not. Blood samples were collected from the diseased camels on the day of admission to our clinic. Blood samples were also collected from 12 healthy camels and were used as controls. The mean serum concentration of cTnI in the camels with tick infestation was 1.7 ± 1.6 ng/ml compared to 0.03 ± 0.02 ng/ml in the controls. The mean serum concentration of cTnI in those camels that recovered was 0.36 ± 0.53 ng/ml compared to 3.0 ± 1.1 ng/ml in the camels that did not. Venous blood gas alterations included an increase in partial pressure of carbon dioxide and decreases in partial pressure of oxygen and oxygen saturation. Haematological parameters involved decreases of red blood cells, haemoglobin and haematocrit and increases in the mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration. Biochemical parameters included significant elevations in the serum activity of aspartate aminotransferase, creatine kinase and alkaline phosphates. Other biochemical alterations observed were decreases in total protein and albumin and increases in globulin and glucose concentrations. In conclusion, the data of this study suggest the possibility of using cTnI as a biomarker for cardiac injury in camels with tick infestation and for the

  2. Influence of dietary copper concentrations on growth performance, serum lipid profiles, antioxidant defenses, and fur quality in growing-furring male blue foxes (Vulpes lagopus).

    PubMed

    Liu, Z; Wu, X; Zhang, T; Cui, H; Guo, J; Guo, Q; Gao, X; Yang, F

    2016-03-01

    A 75-d experiment was conducted to evaluate the influence of dietary Cu concentrations on growth performance, serum lipid profiles, antioxidant defenses, and fur quality in growing-furring male blue foxes. Seventy-five male blue foxes (5.78 ± 0.09 kg BW) were selected and randomly allocated to 1 of the following 5 dietary treatments: 1) control (basal diet without supplemental Cu; 7.78 mg Cu/kg), 2) 12.22 mg/kg supplemental Cu (Cu20), 3) 32.22 mg/kg supplemental Cu, 4) 72.22 mg/kg supplemental Cu (Cu80), and 5) 152.22 mg/kg supplemental Cu (Cu160). A dry feed that consisted of animal meals, soybean meal, extruded corn, and soybean oil was used as the basal diet and Cu was supplemented as reagent grade CuSO∙5HO. The results showed that Cu supplementation increased the ADG ( < 0.05) and fat digestibility ( < 0.01) and tended to improve G:F ( = 0.09). The ADFI, however, was not affected by dietary Cu ( > 0.10). Additionally, Cu supplementation linearly increased the concentration of fecal Cu, liver Cu, serum total protein, and albumin ( < 0.01). Foxes in the Cu160 group had higher serum Cu concentration than those in the control and Cu20 groups ( < 0.05). The concentration of serum cholesterol decreased with dietary Cu supplementation ( < 0.05). Serum high-density lipoprotein, on the contrary, tended to increase with Cu supplementation ( = 0.09). Copper supplementation increased the activity of glutathione peroxidase ( < 0.05) and tended to increase the activity of serum ceruloplasmin ( = 0.07). For fur quality, skin length in the Cu80 group was greater than that in the control and Cu20 groups. In addition, hair color tended to deepen with the increasing of dietary Cu concentrations ( = 0.08). In conclusion, this study demonstrates that Cu supplementation can promote growth and increase fat digestibility and fur length. Additionally, dietary Cu supplementation can enhance antioxidant capacity and reduce serum cholesterol in growing-furring blue foxes.

  3. Influence of dietary copper concentrations on growth performance, serum lipid profiles, antioxidant defenses, and fur quality in growing-furring male blue foxes (Vulpes lagopus).

    PubMed

    Liu, Z; Wu, X; Zhang, T; Cui, H; Guo, J; Guo, Q; Gao, X; Yang, F

    2016-03-01

    A 75-d experiment was conducted to evaluate the influence of dietary Cu concentrations on growth performance, serum lipid profiles, antioxidant defenses, and fur quality in growing-furring male blue foxes. Seventy-five male blue foxes (5.78 ± 0.09 kg BW) were selected and randomly allocated to 1 of the following 5 dietary treatments: 1) control (basal diet without supplemental Cu; 7.78 mg Cu/kg), 2) 12.22 mg/kg supplemental Cu (Cu20), 3) 32.22 mg/kg supplemental Cu, 4) 72.22 mg/kg supplemental Cu (Cu80), and 5) 152.22 mg/kg supplemental Cu (Cu160). A dry feed that consisted of animal meals, soybean meal, extruded corn, and soybean oil was used as the basal diet and Cu was supplemented as reagent grade CuSO∙5HO. The results showed that Cu supplementation increased the ADG ( < 0.05) and fat digestibility ( < 0.01) and tended to improve G:F ( = 0.09). The ADFI, however, was not affected by dietary Cu ( > 0.10). Additionally, Cu supplementation linearly increased the concentration of fecal Cu, liver Cu, serum total protein, and albumin ( < 0.01). Foxes in the Cu160 group had higher serum Cu concentration than those in the control and Cu20 groups ( < 0.05). The concentration of serum cholesterol decreased with dietary Cu supplementation ( < 0.05). Serum high-density lipoprotein, on the contrary, tended to increase with Cu supplementation ( = 0.09). Copper supplementation increased the activity of glutathione peroxidase ( < 0.05) and tended to increase the activity of serum ceruloplasmin ( = 0.07). For fur quality, skin length in the Cu80 group was greater than that in the control and Cu20 groups. In addition, hair color tended to deepen with the increasing of dietary Cu concentrations ( = 0.08). In conclusion, this study demonstrates that Cu supplementation can promote growth and increase fat digestibility and fur length. Additionally, dietary Cu supplementation can enhance antioxidant capacity and reduce serum cholesterol in growing-furring blue foxes. PMID:27065271

  4. Vertical profiles of H2O, H2SO4, and sulfuric acid concentration at 45-75 km on Venus

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, Vladimir A.

    2015-05-01

    A method developed by Krasnopolsky and Pollack (Krasnopolsky, V.A., Pollack, J.B. [1994]. Icarus 109, 58-78) to model vertical profiles of H2O and H2SO4 vapors and sulfuric acid concentration in the Venus cloud layer has been updated with improved thermodynamic parameters for H2O and H2SO4 and reduced photochemical production of sulfuric acid. The model is applied to the global-mean conditions and those at the low latitudes and at 60°. Variations in eddy diffusion near the lower cloud boundary are used to simulate variability in the cloud properties and abundances of H2O and H2SO4. The best version of the model for the global-mean condition results in a lower cloud boundary (LCB) at 47.5 km, H2SO4 peak abundance of 7.5 ppm at the LCB, and H2O mixing ratios of 7 ppm at 62 km and 3.5 ppm above 67 km. The model for low latitudes gives LCB at 48.5 km, the H2SO4 peak of 5 ppm, H2O of 8.5 ppm at 62 km and 3 ppm above 67 km. The model for 60° shows LCB at 46 km, the H2SO4 peak of 8.5 ppm, H2O of 9 ppm at 62 km and 4.5 ppm above 67 km. The calculated variability is induced by the proper changes in the production of sulfuric acid (by factors of 1.2 and 0.7 for the low latitudes and 60°, respectively) and reduction of eddy diffusion near 45 km relative to the value at 54 km by factors of 1.1, 3, and 4.5 for the low and middle (global-mean) latitudes and 60°, respectively. Concentration of sulfuric acid at the low and middle latitudes varies from ∼98% near 50 km to ∼80% at 60 km and then is almost constant at 79% at 70 km. Concentration at 60° is 98% at 50 km, 73% at 63 km, and 81% at 70 km. There is a reasonable agreement between the model results and observations except for the sulfuric acid concentration in the lower clouds. Variations of eddy diffusion in the lower cloud layer simulate variations in atmospheric dynamics and may induce strong variations in water vapor near the cloud tops. Variations in temperature may affect abundances of the H2O and H2SO4 vapors

  5. 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

  6. 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

  7. Lettuce (Lactuca sativa L.) leaf-proteome profiles after exposure to cylindrospermopsin and a microcystin-LR/cylindrospermopsin mixture: a concentration-dependent response.

    PubMed

    Freitas, Marisa; Campos, Alexandre; Azevedo, Joana; Barreiro, Aldo; Planchon, Sébastien; Renaut, Jenny; Vasconcelos, Vitor

    2015-02-01

    The intensification of agricultural productivity is an important challenge worldwide. However, environmental stressors can provide challenges to this intensification. The progressive occurrence of the cyanotoxins cylindrospermopsin (CYN) and microcystin-LR (MC-LR) as a potential consequence of eutrophication and climate change is of increasing concern in the agricultural sector because it has been reported that these cyanotoxins exert harmful effects in crop plants. A proteomic-based approach has been shown to be a suitable tool for the detection and identification of the primary responses of organisms exposed to cyanotoxins. The aim of this study was to compare the leaf-proteome profiles of lettuce plants exposed to environmentally relevant concentrations of CYN and a MC-LR/CYN mixture. Lettuce plants were exposed to 1, 10, and 100 μg/l CYN and a MC-LR/CYN mixture for five days. The proteins of lettuce leaves were separated by two-dimensional electrophoresis (2-DE), and those that were differentially abundant were then identified by matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF/TOF MS). The biological functions of the proteins that were most represented in both experiments were photosynthesis and carbon metabolism and stress/defense response. Proteins involved in protein synthesis and signal transduction were also highly observed in the MC-LR/CYN experiment. Although distinct protein abundance patterns were observed in both experiments, the effects appear to be concentration-dependent, and the effects of the mixture were clearly stronger than those of CYN alone. The obtained results highlight the putative tolerance of lettuce to CYN at concentrations up to 100 μg/l. Furthermore, the combination of CYN with MC-LR at low concentrations (1 μg/l) stimulated a significant increase in the fresh weight (fr. wt) of lettuce leaves and at the proteomic level resulted in the increase in abundance of a high number of proteins. In

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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 %.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. Study of the lipidemic profile of diabetic patients. Negative correlation of cholesterol levels of diabetes type I patients with serum amylase concentration.

    PubMed

    Eleftheriou, Phaedra; Tseka, Eros; Varaga, Evagelia; Nasiou, Margarita; Sampanis, Christos; Zografou, Ioanna; Oulorgia, Jensila; Damontsidou, Katerina; Zaimi, Terpsithea; Markou, Helen-Irene; Varsamidis, Kostantinos; Petrou, Christos; Limberaki, Eugenia; Ganou, Christina-Joulia

    2014-01-01

    Diabetes Mellitus type I (DM1) and II (DM2) share the common characteristic of high blood glucose concentration and the health complications resulting from uncontrolled hyperglycemia such as hyperlipidemia, cardiovascular problems, stroke, ketoacidosis, kidney failure and blindness but have different etiology. DM1 is practically an autoimmune disease. Genetic susceptibility together with environmental factors leads to disease development. The main characteristics of Diabetes type II (DM2) is insulin resistance in muscle and liver cells accompanied by loss of β-cell function. However, adipose tissue, gastro-intestinal tract, pancreatic a-cell activity, may be involved in disease development. In parallel to the impairment of endocrine pancreatic function, a reduction in exocrine function has also been observed in all types of Diabetes Mellitus. A decrease in amylase and lipase activity has been mentioned by many authors, although cases with elevated amylase have been referred. Most recently a trend for positive correlation between HDL cholesterol and amylase in Diabetes type II patients was shown. In the present study we evaluated the lipidemic profile and related factors such as cortisol, total serum antioxidant capacity (TAC) and amylase in patients suffering from diabetes type I and II. The relationship between different parameters was examined. Blood serum from 20 DM1 patients and 45 DM2 patients was used. Serum from 50 healthy individuals was used as control. Total cholesterol and triglycerides were measured using an enzymatic colorimetric method. Serum cortisol, auto-antibodies and anti-Neu5Gc antibodies were measured using immunoenzyme assays and TAC measurement was made using the ABTS method. Mean total cholesterol was 245.5mg/dL in Diabetes I patients and was significantly elevated compared to healthy individuals as well as Diabetes II patients (168.71±76.0mg/dL). The observed difference was statistically significant (P=0.0004). On the contrary

  20. 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.

  1. Effect of Fe2O3 concentration on the structure of the SiO2-Na2O-Al2O3-B2O3 glass system.

    PubMed

    Dantas, Noelio O; Ayta, Walter E F; Silva, Anielle C A; Cano, Nilo F; Silva, Sebastião W; Morais, Paulo C

    2011-10-15

    The structural properties of the glass matrix 40SiO(2)·30Na(2)O·1Al(2)O(3)·(29-x)B(2)O(3)·xFe(2)O(3) (mol%), 0.0≤x≤29.0 were studied by X-ray diffraction (XRD), differential thermal analysis (DTA) and Raman and infrared spectroscopy (FT-IR). XRD demonstrated Fe(3)O(4) crystal formation for Fe(2)O(3) concentrations of 29.0 mol%. DTA showed that glass transition and crystallization temperatures changed as a function of Fe(2)O(3) concentration and that these alterations were related to structural change in the glass system. Interesting aspects of Raman and FT-IR spectra were found, and this gives information about of the structure changes in Si-O-Si units of these glasses as a function of Fe(2)O(3) concentration.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Use of high-pressure CO2 for concentrating CrVI from electroplating wastewater by Mg-Al layered double hydroxide.

    PubMed

    Lv, Xiangying; Chen, Zhi; Wang, Yongjing; Huang, Feng; Lin, Zhang

    2013-11-13

    The desorption of Cr(VI) from Cr(VI)-adsorbed layered double hydroxide (Cr(VI)-LDH) and the recycling of LDH adsorbent are the bottlenecks that limit the practical application of LDH in treating Cr(VI)-containing industrial wastewater. Given the strong affinity of LDH for CO2, we studied desorption and enrichment of Cr(VI) from Cr(VI)-LDH as well as recycling of LDH in the presence of high-pressure CO2. Results showed that Cr(VI) solution with concentration of 500 mg/L could be enriched more than 20 times in each adsorption-desorption cycle. The regenerated LDH maintained the layer structure and the sheets as revealed by XRD and TEM patterns. FT-IR data showed CO2 formed HCO3(-) at high pressure. The transformation from CO2 to HCO3(-) followed by the anion-exchange with CrO4(2-) was the critical factor for Cr(VI) desorption and LDH regeneration. A pilot-scale experiment was carried out with 20 L Cr(VI)-containing electroplating wastewater. The concentration of the desorbed Cr(VI) solution could reach up to 10000 mg/L, which could be used in electroplating after appropriate adjustment. The main advantages of this method are high concentration of Cr(VI), direct reuse of enriched Cr(VI), and efficient regeneration of LDH adsorbent. This method showed promises in recycling Cr(VI) and regenerating LDH in treating industrial wastewater.

  8. Influence of different parameter profiles on the formation of aluminum back surface field (Al-BSF) using for HIT solar cell

    NASA Astrophysics Data System (ADS)

    Zeng, Xiangbin; Zeng, Yu; AL-Naser, Qusay Assim Hanna; Zhou, Chunlan; Zhang, Xiao; Chen, Qiankun; Yang, Yanyan; Liu, Luo

    2009-08-01

    The aluminum back surface field used in p-type substrate hetero-junction with intrinsic thin film (HIT) solar cell is studied in this paper. The enhancement of material quality and the decrease of wafer thickness will make it necessary to passivate the back surface. It simply states the principle and formation process of aluminum back surface field, and studies the evenness of back surface field because it is necessary for high efficiency solar cell. Screen-printing and rapid thermal annealing were used to make aluminum back surface field to gain low recombination on the backside of solar cells. In this experiment, we analyze Al-BSF formed by taking different times and temperatures in which the temperature varied in the range between 620°C and 940 °C step 80°C and the time varied from 60 seconds to 180 seconds with a step of 30 seconds. Minority carrier lifetime with the back surface field was measured by microwave photoconductive decay (μ-PCD) device, analyze and get the optimal parameters of forming Al-BSF and further improve conversion efficiency of silicon solar cell.

  9. 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.

  10. Interdiffusion in Diffusion Couples: U-Mo v. Al and Al-Si

    SciTech Connect

    D. D. Keiser, Jr.; E. Perez; B. Yao; Y. H. Sohn

    2009-11-01

    Interdiffusion and microstructural development in the U-Mo-Al system was examined using solid-tosolid diffusion couples consisting of U-7wt.%Mo, U-10wt.%Mo and U-12wt.%Mo vs. pure Al, annealed at 600°C for 24 hours. The influence of Si alloying addition (up to 5 wt.%) in Al on the interdiffusion microstructural development was also examined using solid-to-solid diffusion couples consisting of U-7wt.%Mo, U-10wt.%Mo and U-12wt.%Mo vs. pure Al, Al-2wt.%Si, and Al-5wt.%Si annealed at 550°C up to 20 hours. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron probe microanalysis (EPMA) were employed to examine the development of a very fine multiphase intermetallic layer. In ternary U-Mo-Al diffusion couples annealed at 600°C for 24 hours, interdiffusion microstructure varied of finely dispersed UAl3, UAl4, U6Mo4Al43, and UMo2Al20 phases while the average composition throughout the interdiffusion zone remained constant at approximately 80 at.% Al. Interdiffusion microstructure observed by SEM/TEM analyses and diffusion paths drawn from concentration profiles determined by EPMA appear to deviate from the assumption of “local thermodynamic equilibrium,” and suggest that interdiffusion occurs via supersaturated UAl4 followed by equilibrium transformation into UAl3, U6Mo4Al43, UAl4 and UMo2Al20 phases. Similar observation was made for U-Mo vs. Al diffusion couples annealed at 550°C. The addition of Si (up to 5 wt.%) in Al significantly reduced the thickness of the intermetallic layer by changing the constituent phases of the interdiffusion zone developed in U-Mo vs. Al-Si diffusion couples. Specifically, the formation of (U,Mo)(Al,Si)3 with relatively large solubility for Mo and Si, along with UMo2Al20 phases was observed along with disappearance of U6Mo4Al43 and UAl4 phases. Simplified understanding based on U-Al, U-Si, and Mo-Si binary phase diagrams is discussed in the light of the beneficial effect of Si alloying addition.

  11. Evaluating the validity and applicable domain of the toxic load model: impact of concentration vs. time profile on inhalation lethality of hydrogen cyanide.

    PubMed

    Sweeney, Lisa M; Sommerville, Douglas R; Channel, Stephen R; Sharits, Brian C; Gargas, Nathan M; Gut, Chester P

    2015-04-01

    The ten Berge model (or "toxic load" model) is often used to estimate the acute toxicity for varying combinations of inhaled concentration and duration. Expressed as C(n) × t = toxic load (TL), TLs are assumed constant for various combinations of concentration (C) and time (t). Experimental data in a recent acute inhalation study of rats exposed to time-varying concentrations of hydrogen cyanide (HCN) supported the validity of the toxic load model except under very brief, discontinuous, high concentration exposures. In the present investigation, experiments were conducted to extend the evaluation of the applicable domain of the model for acute lethality of HCN in the rat (cumulative exposure range of 2900-11,000 ppm min). The lethality of HCN over very short (< 5 min) durations of high concentrations did not conform to the toxic load model. A value of n=1.57 was determined for uninterrupted exposures ⩾ 5 min. For 30-min exposures, the presence or absence of a gap between two exposure pulses of different concentrations, the relative duration, relative height, and the ordering of the pulses (low then high, vs. high then low) did not appear to have a meaningful impact on the toxic load required for median lethality.

  12. 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

  13. 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.

  14. Interaction between differential gene expression profile and phenotype in bovine blastocysts originating from oocytes exposed to elevated non-esterified fatty acid concentrations.

    PubMed

    Van Hoeck, V; Rizos, D; Gutierrez-Adan, A; Pintelon, I; Jorssen, E; Dufort, I; Sirard, M A; Verlaet, A; Hermans, N; Bols, P E J; Leroy, J L M R

    2015-01-01

    Maternal metabolic disorders linked to lipolysis are major risk factors for reproductive failure. A notable feature of such disorders is increased non-esterified fatty acid (NEFA) concentrations in the blood, which are reflected in the ovarian follicular fluid. Elevated NEFA concentrations impact on the maturing oocyte and even alter subsequent embryo physiology. The aetiological mechanisms have not been fully elucidated. Therefore, in the present study, bovine in vitro maturing cumulus-oocyte complexes were exposed (24 h) to three different maturation treatments containing: (1) physiological (72 µM) NEFA concentrations (=control); (2) elevated (75 µM) stearic acid (SA) concentrations (=HIGH SA); and (3) elevated (425 µM) NEFA concentrations (=HIGH COMBI). Zygotes were fertilised and cultured following standard procedures. Transcriptomic analyses in resulting Day 7.5 blastocysts revealed that the major pathways affected are related to lipid and carbohydrate metabolism in HIGH COMBI embryos and to lipid metabolism and cell death in HIGH SA embryos. Furthermore, lower glutathione content and a reduced number of lipid droplets per cell were observed in HIGH SA-exposed oocytes and resulting morulae, respectively, compared with their HIGH COMBI-exposed counterparts. Vitrified embryos originating from HIGH SA-exposed oocytes tended to exhibit lower survival rates compared with controls. These data suggest possible mechanisms explaining why females across species suffering lipolytic disorders experience difficulties in conceiving.

  15. 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.

  16. 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.

  17. ALS Association

    MedlinePlus

    ... toward a world without ALS! Walk to Defeat ALS® Walk to Defeat ALS® draws people of all ... We need your help. I Will Advocate National ALS Registry The National ALS Registry is a congressionally ...

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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.

  3. Frequency and voltage dependence dielectric properties, ac electrical conductivity and electric modulus profiles in Al/Co3O4-PVA/p-Si structures

    NASA Astrophysics Data System (ADS)

    Bilkan, Çiğdem; Azizian-Kalandaragh, Yashar; Altındal, Şemsettin; Shokrani-Havigh, Roya

    2016-11-01

    In this research a simple microwave-assisted method have been used for preparation of cobalt oxide nanostructures. The as-prepared sample has been investigated by UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM). On the other hand, frequency and voltage dependence of both the real and imaginary parts of dielectric constants (ε‧, ε″) and electric modulus (M‧ and M″), loss tangent (tanδ), and ac electrical conductivity (σac) values of Al/Co3O4-PVA/p-Si structures were obtained in the wide range of frequency and voltage using capacitance (C) and conductance (G/ω) data at room temperature. The values of ε‧, ε″ and tanδ were found to decrease with increasing frequency almost for each applied bias voltage, but the changes in these parameters become more effective in the depletion region at low frequencies due to the charges at surface states and their relaxation time and polarization effect. While the value of σ is almost constant at low frequency, increases almost as exponentially at high frequency which are corresponding to σdc and σac, respectively. The M‧ and M″ have low values at low frequencies region and then an increase with frequency due to short-range mobility of charge carriers. While the value of M‧ increase with increasing frequency, the value of M″ shows two peak and the peaks positions shifts to higher frequency with increasing applied voltage due to the decrease of the polarization and Nss effects with increasing frequency.

  4. Investigation of diffusion in AlAs/GaAs distributed Bragg reflectors using HAADF STEM imaging

    NASA Astrophysics Data System (ADS)

    Schowalter, M.; Tewes, M.; Frank, K.; Imlau, R.; Rosenauer, A.; Lee, H. S.; Rastelli, A.; Schmidt, O. G.; Tavast, M.; Leinonen, T.; Guina, M.

    2011-11-01

    In this contribution we have studied the diffusion of Al in AlAs/GaAs distributed Bragg-reflectors using the high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) intensity. The measured intensity is normalized to the intensity of the incoming electron beam using a detector scan. The normalized intensity can be directly compared with a set of frozen lattice simulations yielding specimen thickness in regions with known composition or concentration in regions with known thickness. The thickness was evaluated both from GaAs and AlAs regions yielding that the specimen was about 15 nm thinner in AlAs regions due to oxidation. For the concentration evaluation the thickness was derived from GaAs regions and concentrations up to 1.2 were found due to the overestimated thickness. Concentration profiles were scaled down to 1.0 and fitted to the solution of Fick's laws.

  5. Impact of Mg concentration on energy-band-depth profile of Mg-doped InN epilayers analyzed by hard X-ray photoelectron spectroscopy

    SciTech Connect

    Imura, M.; Tsuda, S.; Nagata, T.; Takeda, H.; Liao, M. Y.; Koide, Y.; Yang, A. L.; Yamashita, Y.; Yoshikawa, H.; Kobayashi, K.; Kaneko, M.; Uematsu, N.; Wang, K.; Araki, T.; Nanishi, Y.

    2013-10-14

    The electronic structures of Mg-doped InN (Mg-InN) epilayers with the Mg concentration, [Mg], ranging from 1 × 10{sup 19} to 5 × 10{sup 19} cm{sup −3} were systematically investigated by soft and hard X-ray photoelectron spectroscopies. The angle-resolved results on the core-level and valence band photoelectron spectra as a function of [Mg] revealed that the energy band of Mg-InN showed downward bending due to the n{sup +} surface electron accumulation and p type layers formed in the bulk. With an increase in [Mg], the energy-band changed from monotonic to two-step n{sup +}p homojunction structures. The oxygen concentration rapidly increased at the middle-bulk region (∼4.5 to ∼7.5 nm) from the surface, which was one of the reasons of the transformation of two-step energy band.

  6. 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.

  7. Effects of corn silage particle size, supplemental hay, and forage-to-concentrate ratio on rumen pH, feed preference, and milk fat profile of dairy cattle.

    PubMed

    Kmicikewycz, A D; Harvatine, K J; Heinrichs, A J

    2015-07-01

    Two experiments (Exp.) were conducted to study effects of feeding long or short corn silage total mixed rations (TMR) on rumen pH, feed preference, and dairy cow performance and to determine the rate of recovery from grain-induced subacute ruminal acidosis (SARA). Both experiments utilized a crossover design with 12 lactating, multiparous, Holstein cows each (including 4 ruminally cannulated cows) and consisted of two 26-d periods. Each period consisted of 12d of adaptation followed by 14d of data collection. Each period was divided into 4 phases: adaptation, d 1 to 12; baseline, d 13 to 14; challenge, d 15 to 19; and recovery, d 20 to 26. Treatments in Exp. 1 were TMR based on corn silage with long (L) or short (ST) particle size in a 65:35 forage-to-concentrate (F:C) diet. Treatments in Exp. 2 were TMR based on corn silage with short (SH) or long (LH) particle size in a 65:35 F:C diet with 3.3% (DM basis) orchardgrass hay offered as a supplement to the diet. In both experiments, during the challenge phase cows received a 50:50 F:C diet to initiate SARA. Animals were housed individually, milked twice per day, and fed once per day for 10% refusal rate on an as-fed basis. Data were analyzed using PROC MIXED of SAS. Feeding L and LH diets increased acetate-to-propionate ratio in the rumen, which resulted in the maintenance of a ratio >2 from the start of the SARA challenge through recovery. In Exp. 1, feeding long corn silage TMR resulted in lower milk fat concentration on the third day of the challenge, whereas cows fed short corn silage TMR had lower milk fat concentration on the final day of the challenge compared with d 13. Providing supplemental hay to cows fed TMR based on long or short corn silage in Exp. 2 prevented acidosis when cows were challenged with a high-grain diet. Milk fat concentrations substantially decreased during the challenge phase in both diets supplemented with hay, but feeding LH did not lower milk fat concentrations until d 20 compared

  8. 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.

  9. Concentration and chemical-state profiles at heterogeneous interfaces with sub-nm accuracy from standing-wave ambient-pressure photoemission

    NASA Astrophysics Data System (ADS)

    Nemšák, Slavomír; Shavorskiy, Andrey; Karslioglu, Osman; Zegkinoglou, Ioannis; Rattanachata, Arunothai; Conlon, Catherine S.; Keqi, Armela; Greene, Peter K.; Burks, Edward C.; Salmassi, Farhad; Gullikson, Eric M.; Yang, See-Hun; Liu, Kai; Bluhm, Hendrik; Fadley, Charles S.

    2014-11-01

    Heterogeneous processes at solid/gas, liquid/gas and solid/liquid interfaces are ubiquitous in modern devices and technologies but often difficult to study quantitatively. Full characterization requires measuring the depth profiles of chemical composition and state with enhanced sensitivity to narrow interfacial regions of a few to several nm in extent over those originating from the bulk phases on either side of the interface. We show for a model system of NaOH and CsOH in an ~1-nm thick hydrated layer on α-Fe2O3 (haematite) that combining ambient-pressure X-ray photoelectron spectroscopy and standing-wave photoemission spectroscopy provides the spatial arrangement of the bulk and interface chemical species, as well as local potential energy variations, along the direction perpendicular to the interface with sub-nm accuracy. Standing-wave ambient-pressure photoemission spectroscopy is thus a very promising technique for measuring such important interfaces, with relevance to energy research, heterogeneous catalysis, electrochemistry, and atmospheric and environmental science.

  10. Effects of gaseous NH{sub 3} and SO{sub 2} on the concentration profiles of PCDD/F in flyash under post-combustion zone conditions

    SciTech Connect

    Hajizadeh, Yaghoub; Onwudili, Jude A.; Williams, Paul T.

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer Influence of NH{sub 3} and SO{sub 2} on 2378-PCDD/F in flyash and flue gases was investigated. Black-Right-Pointing-Pointer NH{sub 3} decreased the concentration of PCDD and PCDF by 34-75% in the flyash. Black-Right-Pointing-Pointer NH{sub 3} decreased the concentration of PCDD and PCDF by 21-40% from the flue gases. Black-Right-Pointing-Pointer SO{sub 2} led to 99% PCDD and 93% PCDF reductions in the flyash. Black-Right-Pointing-Pointer SO{sub 2} led to 89% PCDD and 76% PCDF reductions in the flue gases. - Abstract: The influence of gaseous ammonia and sulphur dioxide on the formation of 2378-substituted PCDD/F on a reference flyash from a municipal waste incinerator has been investigated using a laboratory scale fixed-bed reactor. The reference flyash samples (BCR-490) was reacted under a simulated flue gas stream at temperatures of 225 and 375 Degree-Sign C for 96 h. The experiments were carried out in two series: first with simulated flue gas alone, and then with injection of NH{sub 3} or SO{sub 2} gas into the flue gas just before the reactor inlet. It was found that the injection of gaseous ammonia into the flue gas could decrease the concentration of both PCDD and PCDF by 34-75% from the solid phase and by 21-40% from the gas phase. Converting the results to I-TEQ values, it could reduce the total I-TEQ values of PCDD and PCDF in the sum of the flyash and exhaust flue gas by 42-75% and 24-57% respectively. The application of SO{sub 2} led to 99% and 93% reductions in the PCDD and PCDF average congener concentrations, respectively in the solid phase. In the gas phase, the total reductions were 89% and 76% for PCDD and PCDF, respectively. Moreover, addition of SO{sub 2} reduced the total I-TEQ value of PCDD and PCDF in the flyash and exhaust flue gas together by 60-86% and 72-82% respectively. Sulphur dioxide was more effective than ammonia in suppressing PCDD/F formation in flyash under the conditions investigated.

  11. 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).

  12. 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%).

  13. Effects of oil pollution at Kuwait's greater Al-Burgan oil field on polycyclic aromatic hydrocarbon concentrations in the tissues of the desert lizard Acanthodactylus scutellatus and their ant prey.

    PubMed

    Al-Hashem, Mona A; Brain, Paul F; Omar, Samira A

    2007-11-01

    Using indicator species to monitor the effects of oil pollution was thought to be useful to assess whether local desert reptiles and their insect prey could fulfill such a role in an area damaged in the second Gulf War (1990). Polluted sites with apparently different degrees of contamination (namely tar mat, soot, and clear sites) located at Kuwait's Greater Al-Burgan oil field were compared with control areas outside this region in study conducted in 2002. Five Acanthodactylus scutellatus lizards from each study and control site were humanely killed and stored in a freezer at -20 degrees C until analysis. Ants from the same sites were also collected and treated in a similar manner. Lizard and ant whole body tissues were subjected to gas chromatography-mass spectrometry (GC-MS) to determine concentrations of petroleum hydrocarbons (HCs). The study concentrated on sixteen polycyclic aromatic hydrocarbons (PAHs), EPA priority pollutants used as indicators of petrogenic HC contamination. There were significantly different concentrations of total PAHs in lizards and ants among all four study sites. Of the 16 PAHs, phenanthrene, fluoranthene, and benzo[a]anthracene were present in both lizard and ant samples from the Greater Al-Burgan oil field sites irrespective of the apparent degree of pollution but were undetectable in materials from the control sites. The range of total PAHs in lizards was 26.5-301 ng g(-1) and it was 6.7-82.1 ng g(-1) in ants. Concentrations increased progressively along an expected contamination gradient. Total PAHs were detected in biota even in an area (clear site) that did not appear, virtually, to contain petroleum soil pollution which supports the value of indicator biota species. For all three sites where PAHs were found in biota, the ratio of total PAHs in ants to lizards was consistently 3.3-3.4. These data show that, although 12 years have passed since the Kuwait oil spill catastrophe, all sites are still contaminated with PAHs. Use of

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. Polybrominated diphenyl ethers in surface soils from e-waste recycling areas and industrial areas in South China: concentration levels, congener profile, and inventory.

    PubMed

    Gao, Shutao; Hong, Jianwen; Yu, Zhiqiang; Wang, Jingzhi; Yang, Guoyi; Sheng, Guoying; Fu, Jiamo

    2011-12-01

    Polybrominated diphenyl ethers (PBDEs) were determined in 60 surface soils from two e-waste recycling sites (Qingyuan and Guiyu, China) and their surrounding areas to assess the extent and influence of PBDEs from e-waste recycling sites on the surrounding areas. A total of 32 surface soils from industrial areas in South China were also investigated for comparison. The mean concentrations of total PBDEs in the e-waste recycling sites of Guiyu and Qingyuan were 2,909 and 3,230 ng/g dry weight, respectively, whereas the PBDE concentrations decreased dramatically (1-2 orders of magnitude) with increasing distance from the recycling site, suggesting that the e-waste recycling activities were the major source of PBDEs in the surrounding areas. Decabromodiphenyl ethers accounted for 77.0 to 85.8% of total PBDEs in e-waste recycling areas, whereas it accounted for 90.2% in industrial areas. Principal component analysis showed that the major source of PBDEs in e-waste recycling areas were a combination of penta-, octa-, and deca-BDE commercial formulations, whereas deca-BDE commercial formulations were the major source of PBDE congeners in industrial areas. The inventories of PBDEs gave preliminary estimates of 6.22 tons and 13.4 tons for the e-waste recycling areas and industrial areas. The results suggested that significantly higher PBDEs in the e-waste recycling sites have already affected surrounding areas negatively within a relatively large distance. Because of the environmental persistence, bioaccumulation, and toxicity of PBDEs, improving the recycling techniques employed at such facilities and developing e-waste management policies are necessary.

  20. 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.

  1. Aluminum and silicon diffusion in Fe-Cr-Al alloys

    SciTech Connect

    Heesemann, A.; Schmidtke, E.; Faupel, F.; Kolb-Telieps, A.; Kloewer, J.

    1999-02-05

    Foils of Fe-Cr-Al alloys containing about 20 wt% Cr, 5 wt% Al and additions of Si and reactive elements like Ce, La, Y, Hf, Zr or Ti are widely used as a substrate in metal-supported automotive catalytic converters. In the present paper the authors report on measurements of Al and Si diffusion in Fe-Cr-Al alloys. Due to a lack of suitable radiotracers concentration profiles were obtained by means of electron microprobe analysis. In connection with data evaluation they present numerical calculations assessing the accuracy of the Matano analysis and the thin-film solution of Fick`s 2nd law as function of the thickness of the initial diffusant layer. The results are of general interest, particularly for the evaluation of diffusion measurements involving industrial specimens with given geometry.

  2. Isothermal desulfation of pre-sulfated Pt-BaO/γ-Al2O3 lean NOx trap catalysts with H2: the effect of H2 concentration and the roles of CO2 and H2O

    SciTech Connect

    Kim, Do Heui; Kwak, Ja Hun; Szanyi, Janos; Peden, Charles HF

    2012-01-12

    The desulfation mechanisms of pre-sulfated Pt-BaO/{gamma}-Al{sub 2}O{sub 3} lean NOx trap catalysts were investigated under isothermal conditions (600 C) using H{sub 2} as the reductant. Sulfates were found to be reduced first with H{sub 2} to produce SO{sub 2}, followed by a reaction between SO{sub 2} and H{sub 2} to produce H{sub 2}S. Gas analysis during the rich pulse reveals that the sulfur removal efficiency is initially proportional to the H{sub 2} concentration. At constant H{sub 2} concentration the overall desulfation efficiency decreases in the order of H{sub 2}/CO{sub 2}/H{sub 2}O > H{sub 2}/CO{sub 2} > H{sub 2}/H{sub 2}O > H{sub 2}, as confirmed by XPS analysis of residual sulfur in the desulfated samples. H{sub 2}O limits the evolution of SO{sub 2} at an early stage of the rich pulse and enhances the production of H{sub 2}S in later stages of reduction. CO{sub 2} is involved in both the formation of COS and the production of H{sub 2}O (via the reverse water-gas shift reaction), therefore, resulting in an increased overall efficiency.

  3. 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 -- ...

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. 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.

  9. Relative concentration of Cry1A in maize leaves and cotton bolls with diverse chlorophyll content and corresponding larval development of fall armyworm (Lepidoptera: Noctuidae) and southwestern corn borer (Lepidoptera: Crambidae) on maize whorl leaf profiles.

    PubMed

    Abel, Craig A; Adamczyk, John J

    2004-10-01

    To manage insect resistance to transgenic crops that express insecticidal proteins from Bacillus thuringiensis (Bt) Berliner, the U.S. Environmental Protection Agency recommends a refuge-based insect resistance management strategy where a percentage of non-Bt (refuge) crop is grown in proximity to a Bt-expressing crop. An important requirement for this strategy is that the toxin exists at a high effective dose for control of the target pest(s), so that heterozygous individuals in the population do not reach adulthood. Factors that cause reduced levels of toxin in the plant are a threat to this strategy. We quantified Cry1Ab from different areas of the maize, Zea mays L., leaf. In general, the distal tip of the V7 maize leaf had a higher concentration of Cry1Ab compared with the middle section of the V7 leaf, and the middle section of the developing V9 leaf had the lowest concentration of Cry1Ab. When these sections of maize tissue were fed to fall armyworm, Spodoptera frugiperda (J.E. Smith), and southwestern corn borer, Diatraea grandiosella Dyar, there was not a reduction in development or an increase in mortality with tissue that had higher concentrations of toxin. Another study tested the relative concentration of Cry1Ab between the white-yellow, yellow-green, and green portions of the developing ninth leaf within the maize whorl. There were differences in Cry1Ab concentration among these leaf areas. The green tissue had the highest concentration of toxin followed by the yellow-green and white-yellow tissues. Correlations between concentration of Cry1Ab and 5-d fall armyworm larval weights among the three leaf color profiles were all significant and negative, i.e., decreased concentration of Cry1Ab in the leaf tissue resulted in increased 5-d larval weights. There was 100% mortality to the southwestern corn borer larvae fed Cry1Ab maize leaf tissue. Differences in the amount of Cry1Ab in the developing V9 leaf profiles did not alter the absolute susceptibility

  10. 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.

  11. 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

  12. Thermal stability of Al-Cu-Fe icosahedral alloys

    NASA Astrophysics Data System (ADS)

    Bessière, M.; Quivy, A.; Lefebvre, S.; Devaud-Rzepski, J.; Calvayrac, Y.

    1991-12-01

    A stable ideally quasiperiodic phase exists in a small range of concentration, close to the composition Al{62}Cu{25.5}Fe{12.5}. Reducing the iron content, or replacing small amounts of copper by aluminium, lead to icosahedral alloys which exhibit around 650 ^{circ}C structural transformations of unclear nature: in the X-ray powder diffraction pattern, the peak profiles become purely Lorentzian (Al{62.3}Cu{25.3}Fe{12.4}) or diffuse “side-bands” appear in the tails of the Bragg peaks (Al{63}Cu{24.5}Fe{12.5}). In the last case long annealing treatments eventually transform the Bragg peaks into diffuse peaks located at positions clearly off the ideal icosahedral symmetry. Small deviations from this composition range lead to Bragg peaks with shoulders whatever the heat-treatment may be; perfect icosahedral order is never obtained for these compositions (Al{63,25}Cu{24,5}Fe{12,25}, Al{64}Cu{24}Fe{12}, Al{63}Cu{25}Fe{12}). Une phase stable idéalement quasipériodique existe dans un petit domaine de concentration, au voisinage de la composition Al{62}Cu{25,5}Fe{12,5}. La diminution de la teneur en fer, ou le remplacement de faibles quantités de cuivre par de l'aluminium, conduisent à des alliages icosaédriques qui subissent vers 650 ^{circ}C des transformations structurales dont la nature n'est pas clairement identifiée: dans le diagramme de diffraction des rayons X sur poudre, les profils de raies deviennent purement Lorentziens (Al{62,3}Cu{25,3}Fe{12,4}) ou bien des raies diffuses apparaissent dans le pied des pics de Bragg (Al{63}Cu{24,5}Fe{12,5}). Dans ce dernier cas un long traitement de recuit transforme finalement les pics de Bragg en des pics diffus localisés à des positions clairement en dehors de celles correspondant à la symétrie icosaédrique idéale. De faibles écarts à ce domaine de compositions conduisent à des diagrammes de rayons X où les pics de Bragg sont épaulés quel que soit le traitement thermique ; l'ordre icosaédrique parfait n

  13. 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).

  14. 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

  15. 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.

  16. Elliptical concentrators.

    PubMed

    Garcia-Botella, Angel; Fernandez-Balbuena, Antonio Alvarez; Bernabeu, Eusebio

    2006-10-10

    Nonimaging optics is a field devoted to the design of optical components for applications such as solar concentration or illumination. In this field, many different techniques have been used to produce optical devices, including the use of reflective and refractive components or inverse engineering techniques. However, many of these optical components are based on translational symmetries, rotational symmetries, or free-form surfaces. We study a new family of nonimaging concentrators called elliptical concentrators. This new family of concentrators provides new capabilities and can have different configurations, either homofocal or nonhomofocal. Translational and rotational concentrators can be considered as particular cases of elliptical concentrators. PMID:17068595

  17. Tracer diffusion in pure and boron-doped Ni/sub 3/Al

    SciTech Connect

    Hoshino, K.; Rothman, S.J.; Averback, R.S.

    1988-05-01

    Diffusion of /sup 63/Ni has been measured in pure and boron-doped polycrystalline Ni/sub 3/Al intermetallic compounds as a function of temperature (692-1352/sup 0/C), Al concentration (24-26 at.%Al), and boron content (0-500 wt ppm). Volume and grain-boundary diffusion of /sup 60/Co and /sup 68/Ge have also been measured in pure Ni/sub 3/Al. Both conventional grinding and ion beam sputtering techniques have been used for the determination of the concentration profiles. The diffusivity of Ni,D*/sub Ni/ is independent of Al content above 1000/sup 0/C, indicating that antisite defects are prevailing on both sides of stoichiometry. However, D*/sub Ni/ shows a minimum at the stoichiometric composition below 1000/sup 0/C, and this trend becomes clearer with decreasing temperature. The diffusivities of /sup 60/Co and /sup 68/Ge are also independent of Al concentration in the temperature range between 880 and 1200/sup 0/C, but their grain-boundary diffusion depends on Al concentration. The addition of boron linearly increases D*/sub Ni/ above 1000/sup 0/C, but at lower temperatures, D*/sub Ni/ in off-stoichiometric compositions decreases to the value for stoichiometric Ni/sub 3/Al on the addition of 100 wt ppm boron, and then increases as above with the further additions of boron to -- 500 wt ppm. The present diffusion data suggest that a small concentration of vacancies, independent of temperature, is present on both sides of, and at, stoichiometry at low temperature.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Meteoric 10Be in soil profiles - A global meta-analysis

    USGS Publications Warehouse

    Graly, Joseph A.; Bierman, Paul R.; Reusser, Lucas J.; Pavich, Milan J.

    2010-01-01

    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.

  3. 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.

  4. 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

  5. SEMICONDUCTOR DEVICES: Influence of Ni Schottky contact thickness on two-dimensional electron-gas sheet carrier concentration of strained Al0.3Ga0.7N/GaN heterostructures

    NASA Astrophysics Data System (ADS)

    Jianzhi, Zhao; Zhaojun, Lin; Yuanjie, Lu; D, Corrigan Timothy; Lingguo, Meng; Yu, Zhang; Zhanguo, Wang; Hong, Chen

    2010-08-01

    Ni/Au Schottky contacts with thicknesses of either 50 Å/50 Å or 600 Å/2000 Å were deposited on strained Al0.3Ga0.7N/GaN heterostructures. Using the measured C-V curves and I-V characteristics at room temperature, the calculated density of the two-dimensional electron-gas (2DEG) of the 600 Å/2000 Å thick Ni/Au Schottky contact is about 9.13 × 1012 cm-2 and that of the 50 Å/50 Å. thick Ni/Au Schottky contact is only about 4.77 × 1012 cm-2. The saturated current increases from 60.88 to 86.34 mA at a bias of 20 V as the thickness of the Ni/Au Schottky contact increases from 50 Å/50 Å to 600 Å/2000 Å. By self-consistently solving Schrodinger's and Poisson's equations, the polarization charge sheet density of the two samples was calculated, and the calculated results show that the polarization in the AlGaN barrier layer for the thick Ni/Au Schottky contact is stronger than the thin one. Thus, we attribute the results to the increased biaxial tensile stress in the Al0.3 Ga0.7N barrier layer induced by the 600 Å/2000 Å thick Ni/Au Schottky contact.

  6. A carbon-14 depth profile in the L5 chondrite Knyahinya

    NASA Astrophysics Data System (ADS)

    Jull, A. J. T.; Donahue, D. J.; Reedy, R. C.; Masarik, J.

    1994-09-01

    We report on a series of measurements of C-14 in samples of the L-chondrite Knyahinya, as a function of depth. The results show C-14 concentrations ranging from 37 to 58 dpm/kg. These measurements are compared to the levels of Ne-21, Be-10 and noble-gas ratios in this meteorite reported by Graf et al (1990). We also compare the C-14 data to the expected profile based on two sets of model calculations. The behavior of this radioisotope with depth is similar to that expected from the models, and good agreement with the profiles of other nuclides is also observed.

  7. A carbon-14 depth profile in the L5 chondrite Knyahinya

    NASA Technical Reports Server (NTRS)

    Jull, A. J. T.; Donahue, D. J.; Reedy, R. C.; Masarik, J.

    1994-01-01

    We report on a series of measurements of C-14 in samples of the L-chondrite Knyahinya, as a function of depth. The results show C-14 concentrations ranging from 37 to 58 dpm/kg. These measurements are compared to the levels of Ne-21, Be-10 and noble-gas ratios in this meteorite reported by Graf et al (1990). We also compare the C-14 data to the expected profile based on two sets of model calculations. The behavior of this radioisotope with depth is similar to that expected from the models, and good agreement with the profiles of other nuclides is also observed.

  8. 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)

  9. 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)

  10. 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

  11. 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

  12. 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.

  13. 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)

  14. 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.

  15. Depth dependences of the ion bombardment induced roughness and of the interdiffusion coefficient for Si/Al multilayers

    NASA Astrophysics Data System (ADS)

    Wang, J. Y.; Zalar, A.; Mittemeijer, E. J.

    2004-01-01

    Depth dependences of the ion bombardment induced roughness and of the interdiffusion coefficient observed by Auger electron spectroscopical (AES) depth profiling of stationary as-deposited and annealed Si/Al multilayered specimens were evaluated by fitting calculated concentration-depth profiles to measured ones. The model used for calculation of the concentration-depth profile accounts for the instrumental smearing (interface broadening) upon AES depth profiling and, if relevant, interdiffusion. The instrumental smearing incorporates the effects of atomic mixing, roughness, escape depth of the Auger electrons, and preferential sputtering. The depth profile recorded from a stationary as-deposited Si/Al multilayered specimen was fitted by assuming, additionally, that the ion bombardment induced roughness increases with the sputter depth, keeping the other fitting parameters (including the inherent surface roughness) equal to the values determined for a rotating specimen. The roughness values determined by fitting to the measured depth profiles agree well with those determined directly by atomic force microscopy (AFM). Interdiffusion at the Si/Al interfaces was induced by annealing the specimens isothermally in an argon atmosphere at 120 °C for 240 min, 135 °C for 60 min, and 150 °C for 20 min. It was found that interdiffusion across interfaces near the surface of the multilayer is more pronounced than across interfaces in the deeper part of the layer. To account for this depth dependence of the extent of interdiffusion, calculated depth profiles for the annealed specimens were fitted to measured ones by assuming that diffusion annealing can be described as an additional "roughening" of the interfaces. As a result, values of the interdiffusion coefficient as a function of the depth beneath the surface were obtained. The depth dependence of the interdiffusion coefficient was discussed in terms of the microstructural development.

  16. Profile summary.

    PubMed

    2003-01-01

    All drugs appearing in the Adis Profile Summary table have been selected based on information contained in R&D Insight trade mark, a proprietary product of Adis International. The information in the profiles is gathered from the world's medical and scientific literature, at international conferences and symposia, and directly from the developing companies themselves. The emphasis of Drugs in R&D is on the clinical potential of new drugs, and selection of agents for inclusion is based on products in late-phase clinical development that have recently had a significant change in status.

  17. 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.

  18. 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.

  19. Stoichiometry dependence of potential screening at La ( 1 - δ ) Al ( 1 + δ ) O 3 / SrTiO 3 interfaces

    DOE PAGES

    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

  20. Ranking Profiles

    ERIC Educational Resources Information Center

    Van Der Werf, Martin

    2007-01-01

    This article presents the "U.S. News" ranking profiles of four colleges, namely: (1) Smith College; (2) Washington University in St. Louis; (3) Colorado State University at Fort Collins; and (4) Whitman College. Smith College was in the top 10 of the nation's liberal-arts colleges, or just outside it, almost since the "U.S. News" rankings began.…

  1. 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.

  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. 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

  4. 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.

  5. 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.

  6. Effect of concentrate supplementation on feed consumption, nutrient utilization and blood metabolite profile in captive spotted deer (Axis axis) fed oat (Avena sativa) and berseem (Trifolium alexandrinum) fodders based diet.

    PubMed

    Suresh, C; Das, A; Katole, Shrikant; Saini, Mohini; Swarup, D

    2013-03-01

    This experiment was conducted to determine the optimum level of a maize-soybean meal-wheat bran concentrate supplement fed to captive spotted deer fed an oat and berseem fodder-based diet. Twelve adult spotted deer [64-76 kg body weight (BW)] were distributed into three groups of four each and were housed individually. A diet consisting of 5 kg of oat fodder and 5.5 kg of berseem fodder was offered to each one of the experimental animals. The animal in group I received no supplementary concentrate, whereas, those in groups II and III received 0.5 and 1 kg of supplementary concentrate, respectively. A 60 days digestibility trial was conducted with a 5 days collection period on Days 55-59 of the trial. Blood samples were collected from all animals on Day 60 of the experiment. Average daily dry matter intake (DMI) was 1,224, 1,613, and 1,574 g/day in groups I, II, and III, respectively. Dry matter (DM) and organic matter (OM) intake was lowest (P < 0.01) in group I. Intake of P, Cu, and Zn was highest (P < 0.01) in group III, followed by groups II and I. Digestibility of neutral detergent fiber was highest (P < 0.05) in group II. Digestibility of OM and CP was lowest (P < 0.05) in group I. Digestibility of gross energy was highest (P < 0.01) in group III (74.9%), followed by groups II (69.3%) and I (66.2%). Digestible energy (DE) intake (kcal/kg BW(0.75) ) was highest (P < 0.01) in group III (195.4), followed by groups II (180.9) and I (129.8). Initial BW was 72.7, 72.5, and 71.0 kg, whereas, final BW was 71.0, 72.7, and 73.5 kg, in groups I, II and III, respectively. Average daily change in body mass was significantly (P < 0.01) different among the groups. The body mass was lost (-29.2 g/day), maintained (4.1 g/day) and gained (41.6 g/day) in groups I, II, and III, respectively. Blood glucose and cholesterol concentration was highest (P < 0.05) in group III, followed by groups II and I. Serum concentration of Cu and

  7. 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.

  8. Chemical trend of superconducting transition temperature in hole-doped delafossite of CuAlO2, AgAlO2 and AuAlO2

    NASA Astrophysics Data System (ADS)

    Nakanishi, Akitaka; Katayama-Yoshida, Hiroshi

    2012-12-01

    We have performed the first-principles calculations about the superconducting transition temperature Tc of hole-doped delafossite CuAlO2, AgAlO2 and AuAlO2. Calculated Tc are about 50 K (CuAlO2), 40 K (AgAlO2) and 3 K(AuAlO2) at maximum in the optimum hole-doping concentration. The low Tc of AuAlO2 is attributed to the weak electron-phonon interaction caused by the low covalency and heavy atomic mass.

  9. 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

  10. 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).

  11. 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

  12. Use of reverse-phase liquid chromatography, linked to tandem mass spectrometry, to profile the Calvin cycle and other metabolic intermediates in Arabidopsis rosettes at different carbon dioxide concentrations.

    PubMed

    Arrivault, Stéphanie; Guenther, Manuela; Ivakov, Alexander; Feil, Regina; Vosloh, Daniel; van Dongen, Joost T; Sulpice, Ronan; Stitt, Mark

    2009-09-01

    A platform using reverse-phase liquid chromatography coupled to tandem mass spectrometry was developed to measure 28 metabolites from photosynthetic metabolism. It was validated by comparison with authentic standards, with a requirement for distinct and clearly separated peaks, high sensitivity and repeatability in Arabidopsis rosette extracts. The recovery of authentic standards added to the plant material before extraction was 80-120%, demonstrating the reliability of the extraction and analytic procedures. Some metabolites could not be reliably measured, and were extracted and determined by other methods. Measurements of 37 metabolites in Arabidopsis rosettes after 15 min of illumination at different CO(2) concentrations showed that most Calvin cycle intermediates remain unaltered, or decrease only slightly (<30%), at compensation point CO(2), whereas dedicated metabolites in end-product synthesis pathways decrease strongly. The inhibition of end-product synthesis allows high levels of metabolites to be retained in the Calvin cycle to support a rapid cycle with photorespiration.

  13. 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.

  14. 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.

  15. An Overview of Concentrated Insulin Products.

    PubMed

    Painter, Nathan A; Sisson, Evan

    2016-08-01

    IN BRIEF This article provides a summary of the use of available concentrated insulins in the outpatient treatment of patients with diabetes. Concentrated insulins work through the same mechanisms as other insulin products. They vary from each other in concentrations and pharmacokinetic/pharmacodynamics profiles but are each similar to their U-100 concentration counterparts. Patient education is important to minimize errors and the risk of hypoglycemia when using these insulin formulations.

  16. Reaction layer growth and reaction heat of U-Mo/Al dispersion fuels using centrifugally atomized powders

    NASA Astrophysics Data System (ADS)

    Ryu, Ho Jin; Han, Young Soo; Park, Jong Man; Park, Soon Dal; Kim, Chang Kyu

    2003-09-01

    The growth behavior of reaction layers and heat generation during the reaction between U-Mo powders and the Al matrix in U-Mo/Al dispersion fuels were investigated. Annealing of 10 vol.% U-10Mo/Al dispersion fuels at temperatures from 500 to 550 °C was carried out for 10 min to 36 h to measure the growth rate and the activation energy for the growth of reaction layers. The concentration profiles of reaction layers between the U-10Mo vs. Al diffusion couples were measured and the integrated interdiffusion coefficients were calculated for the U and Al in the reaction layers. Heat generation of U-Mo/Al dispersion fuels with 10-50 vol.% of U-Mo fuel during the thermal cycle from room temperature to 700 °C was measured employing the differential scanning calorimetry. Exothermic heat from the reaction between U-Mo and the Al matrix is the largest when the volume fraction of U-Mo fuel is about 30 vol.%. The unreacted fraction in the U-Mo powders increases as the volume fraction of U-Mo fuel increases from 30 to 50 vol.%.

  17. 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.

  18. Specific natural isotope profile studied by isotope ratio mass spectrometry (SNIP-IRMS): (13)C/(12)C ratios of fructose, glucose, and sucrose for improved detection of sugar addition to pineapple juices and concentrates.

    PubMed

    González, J; Remaud, G; Jamin, E; Naulet, N; Martin, G G

    1999-06-01

    The delta(13)C values of fructose, glucose, and sucrose have been determined in authentic pineapple juices. The sugar fraction is separated from the organic acids by an anionic exchange process. Then the individual components (fructose, glucose, and sucrose) are isolated on a preparative HPLC device using a NH(2)-type column. It is demonstrated that no significant isotope fractionation occurs when close to 100% of material is recovered and when the hydrolysis of sucrose is avoided. The control of the recovery rates and of the sucrose hydrolysis rate after purification is recommended for a reliable interpretation of the results. Correlations between the delta(13)C values of fructose (delta(13)Cf), glucose (delta(13)Cg), and sucrose (delta(13)Csu) can be characterized by systematic differences between these values. For the set of measurements on authentic pineapple juices and concentrates, the mean and the standard deviation of the differences are delta(13)Cf - delta(13)Cg = -0.6 +/- 0.6 per thousand, delta(13)Cf - delta(13)Csu = -1.3 +/- 0. 6 per thousand, and delta(13)Cf - delta(13)Csu = -0.7 +/- 0.5 per thousand. The determinations of the (13)C content of fructose, glucose, and sucrose enable a refinement of the detection of added sugars in fruit juices, re-enforcing the SNIP-IRMS method. PMID:10794628

  19. 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

  20. 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.

  1. 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.

  2. Charge profile in thin layers of Al2O3

    NASA Astrophysics Data System (ADS)

    Kliem, H.; Schmidt, R.; Arlt, G.

    1982-03-01

    The distribution of trapped electrons with respect to space and energy in thin layers of aluminum oxide of MAOS (metal-aluminumoxide-siliconoxide-silicon) capacitors was studied by photoionization. The oxide layers were charged from the n-type silicon by high field injection in the dark. Afterwards it was possible to release more than 85% of the trapped carriers using photons with energies up to 4.2 eV. The measurements of both the flatband voltages and the discharge currents of several bands of photon energies yielded two parameters for the determination of the spatial distribution for the trapped electrons in each energy interval.

  3. 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…

  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. Thermodynamics and surface properties of liquid Al-Ga and Al-Ge alloys

    NASA Astrophysics Data System (ADS)

    Anusionwu, B. C.; Adebayo, G. A.; Madu, C. A.

    2009-11-01

    The surface properties of Al-Ga and Al-Ge liquid alloys have been theoretically investigated at a temperature of 1100 K and 1220 K respectively. For the Al-Ga system, the quasi chemical model for regular alloy and a model for phase segregating alloy systems were applied, while for the Al-Ge system the quasi chemical model for regular and compound forming binary alloys were applied. In the case of Al-Ga, the models for the regular alloys and that for the phase segregating alloys produced the same value of order energy and same values of thermodynamic and surface properties, while for the Al-Ge system, the model for the regular alloy reproduced better the thermodynamic properties of the alloy. The model for the compound forming systems showed a qualitative trend with the measured values of the thermodynamic properties of the Al-Ge alloy and suggests the presence of a weak complex of the form Al2Ge3. The surface concentrations for the alloys show that Ga manifests some level of surface segregation in Al-Ga liquid alloy while the surface concentration of Ge in Al-Ge liquid alloy showed a near Roultian behavior below 0.8 atomic fraction of Ge.

  6. 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)

  7. 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.

  8. 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.

  9. 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.

  10. Chemical profile of size-fractionated soils collected in a semiarid industrial area of Argentina

    NASA Astrophysics Data System (ADS)

    Morales Del Mastro, Anabella; Pereyra, Marcelo; Londonio, Agustín; Pereyra, Victoria; Rebagliati, Raúl Jiménez; Dawidowski, Laura; Gómez, Darío; Smichowski, Patricia

    2014-12-01

    A study was undertaken to assess the chemical profile of soil collected in Bahía Blanca (Argentina). In this industrial city, semiarid soils are affected by different industrial and agricultural activities, the presence of a saltpeter extraction facility, traffic and increasing urbanization. Sixteen soil samples (superficial and sub-superficial) were collected. Samples were sieved in two fractions (A < 37 μm, and 37 < B < 50 μm) before elemental analysis. Major, minor and trace elements namely, Al, As, Ba, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sb, Ti, V and Zn were determined by inductively coupled plasma optical emission spectrometry (ICP OES). Anions (Cl-, F-, SO42-) and cations (K+, Na+ and NH4+) were determined by high performance liquid chromatography (HPLC) after an aqueous extraction. As expected, crustal elements namely, Al, Ca, Fe, Mg and Ti exhibited the highest concentrations. Mean elemental concentration ranged from <0.3 μg g-1 (Sb) to 14.6 ± 0.6% (Ca). Ions concentrations in the soluble fraction measured at mg g-1 levels were in the order Cl- > Na+ ≅ SO42- > K+ > NO3-. Three indicators, namely, (i) coefficient of variation, (ii) coefficient of divergence and (iii) ratio of elemental concentration with respect to Ca were used to assess chemical, spatial and inter-profile variability. Chloride > Ca > Na+ > Mo > SO42-, dominated the variability indicating that these are key chemical markers for future assessment of crustal contribution to airborne particles in the area. The ratios Xi/Ca allowed discriminating the soil of the semi-arid region surrounding Bahía Blanca. The chemical profiles obtained in this study, particularly those of topsoil, will be a key input to characterize soil resuspension and its contribution to airborne particulate matter in a forthcoming receptor model analysis.

  11. Preparation and characterization of Ppy/Al 2O 3/Al used as a solid-state capacitor

    NASA Astrophysics Data System (ADS)

    Tsai, Ming-Liao; Chen, Pei-Jiun; Do, Jing-Shan

    The characteristics of a solid-state capacitor based on Ppy (polypyrrole)/Al 2O 3/Al prepared by the constant-current method are investigated. The surface composition of aluminum (Al) foil analyzed to by electron spectroscopy for chemical analysis (ESCA) is found to be AlO 2- when the native oxide on the Al foil is etched by 0.1 M NaOH. Three stages are defined from the relationship between the potential and the electrolysis time in simultaneously preparing the dielectric layer (Al 2O 3) and the conducting polymer (Ppy) on Al foil etched with 0.1 M NaOH. The experimental results indicate that only stage one, i.e. the formation of Al 2O 3, occurs in the preparation of Ppy/Al 2O 3/Al at a current density greater than 0.9 mA cm -2. A higher concentration of pyrrole enhances the nucleation of Ppy within the pores of Al 2O 3 such that the period of the first stage decrease and the second stage of the propagation of Ppy is increased. The leakage current of Ppy/Al 2O 3/Al rises from 0.009 to 0.405 μA cm -2 with increase in the concentration of pyrrole in preparing Ppy/Al 2O 3/Al from 0.05 to 0.15 M. Raising the cut-off potential for preparing Ppy/Al 2O 3/Al from 20 to 60 V increases the thickness of Al 2O 3 and lowers the capacity of Ppy/Al 2O 3/Al from 478.5 to 174.2 nF cm -2.

  12. Concentration gradient focusing and separation in a silica nanofluidic channel with a non-uniform electroosmotic flow.

    PubMed

    Hsu, Wei-Lun; Harvie, Dalton J E; Davidson, Malcolm R; Jeong, Helen; Goldys, Ewa M; Inglis, David W

    2014-09-21

    The simultaneous concentration gradient focusing and separation of proteins in a silica nanofluidic channel of various geometries is investigated experimentally and theoretically. Previous modelling of a similar device [Inglis et al., Angew. Chem. Int. Ed., 2011, 50, 7546] assumed a uniform velocity profile along the length of the nanochannel. Using detailed numerical analysis incorporating charge regulation and viscoelectric effects, we show that in reality the varying axial electric field and varying electric double layer thickness caused by the concentration gradient, induce a highly non-uniform velocity profile, fundamentally altering the protein trapping mechanism: the direction of the local electroosmotic flow reverses and two local vortices are formed near the centreline of the nanochannel at the low salt concentration end, enhancing trapping efficiency. Simulation results for yellow/red fluorescent protein R-PE concentration enhancement, peak focusing position and peak focusing width are in good agreement with experimental measurements, validating the model. The predicted separation of yellow/red (R-PE) from green (Dyl-Strep) fluorescent proteins mimics that from a previous experiment [Inglis et al., Angew. Chem. Int. Ed., 2011, 50, 7546] conducted in a slightly different geometry. The results will inform the design of new class of matrix-free particle focusing and separation devices. PMID:25027204

  13. 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.

  14. 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.

  15. AlN homoepitaxial growth on sublimation-AlN substrate by low-pressure HVPE

    NASA Astrophysics Data System (ADS)

    Nomura, Takuya; Okumura, Kenta; Miyake, Hideto; Hiramatsu, Kazumasa; Eryu, Osamu; Yamada, Yoichi

    2012-07-01

    Crack-free thick AlN layers with low impurity concentrations were grown on free-standing AlN substrates fabricated by a sublimation method. Cracks due to tensile stresses were generated in the overgrowth layer when using on-axis AlN (0 0 0 1) substrates, as indicated by Raman scattering spectroscopy. In contrast, cracks were not generated when using 5° off-angle AlN (0 0 0 1) substrates. High crystalline quality was indicated by X-ray rocking curve (XRC) analysis. The full width at half maximum (FWHM) values of the (0 0 0 2) and (1 0-1 0) diffractions were 277 and 306 arcsec, respectively. Secondary ion mass spectrometry (SIMS) measurements indicated that the Si and C impurity concentrations were reduced to half of those in the sublimation-grown AlN substrates.

  16. Highly strained AlAs-type interfaces in InAs/AlSb heterostructures

    NASA Astrophysics Data System (ADS)

    Vallet, M.; Claveau, Y.; Warot-Fonrose, B.; Gatel, C.; Nicolai, J.; Combe, N.; Magen, C.; Teissier, R.; Baranov, A. N.; Ponchet, A.

    2016-05-01

    Spontaneously formed Al-As type interfaces of the InAs/AlSb system grown by molecular beam epitaxy for quantum cascade lasers were investigated by atomic resolution scanning transmission electron microscopy. Experimental strain profiles were compared to those coming from a model structure. High negative out-of-plane strains with the same order of magnitude as perfect Al-As interfaces were observed. The effects of the geometrical phase analysis used for strain determination were evidenced and discussed in the case of abrupt and huge variations of both atomic composition and bond length as observed in these interfaces. Intensity profiles performed on the same images confirmed that changes of chemical composition are the source of high strain fields at interfaces. The results show that spontaneously assembled interfaces are not perfect but extend over 2 or 3 monolayers.

  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. 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...

  19. 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.

  20. High-dimensional entanglement concentration of twisted photon pairs High-dimensional entanglement concentration

    NASA Astrophysics Data System (ADS)

    Chen, L. X.; Wu, Q. P.

    2012-10-01

    Recently, Dada et al. reported on the experimental entanglement concentration and violation of generalized Bell inequalities with orbital angular momentum (OAM) [Nat. Phys. 7, 677 (2011)]. Here we demonstrate that the high-dimensional entanglement concentration can be performed in arbitrary OAM subspaces with selectivity. Instead of violating the generalized Bell inequalities, the working principle of present entanglement concentration is visualized by the biphoton OAM Klyshko picture, and its good performance is confirmed and quantified through the experimental Shannon dimensionalities after concentration.

  1. Odorant concentration differentiator for intermittent olfactory signals.

    PubMed

    Fujiwara, Terufumi; Kazawa, Tomoki; Sakurai, Takeshi; Fukushima, Ryota; Uchino, Keiro; Yamagata, Tomoko; Namiki, Shigehiro; Haupt, Stephan Shuichi; Kanzaki, Ryohei

    2014-12-10

    Animals need to discriminate differences in spatiotemporally distributed sensory signals in terms of quality as well as quantity for generating adaptive behavior. Olfactory signals characterized by odor identity and concentration are intermittently distributed in the environment. From these intervals of stimulation, animals process odorant concentration to localize partners or food sources. Although concentration-response characteristics in olfactory neurons have traditionally been investigated using single stimulus pulses, their behavior under intermittent stimulus regimens remains largely elusive. Using the silkmoth (Bombyx mori) pheromone processing system, a simple and behaviorally well-defined model for olfaction, we investigated the neuronal representation of odorant concentration upon intermittent stimulation in the naturally occurring range. To the first stimulus in a series, the responses of antennal lobe (AL) projection neurons (PNs) showed a concentration dependence as previously shown in many olfactory systems. However, PN response amplitudes dynamically changed upon exposure to intermittent stimuli of the same odorant concentration and settled to a constant, largely concentration-independent level. As a result, PN responses emphasized odorant concentration changes rather than encoding absolute concentration in pulse trains of stimuli. Olfactory receptor neurons did not contribute to this response transformation which was due to long-lasting inhibition affecting PNs in the AL. Simulations confirmed that inhibition also provides advantages when stimuli have naturalistic properties. The primary olfactory center thus functions as an odorant concentration differentiator to efficiently detect concentration changes, thereby improving odorant source orientation over a wide concentration range.

  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. 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.

  4. 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

  5. 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

  6. 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

  7. Surface Al doping of 4H-SiC via low temperature annealing

    NASA Astrophysics Data System (ADS)

    Park, Junbo; Kim, Ki-hwan; Park, Young-rak; Kim, Minki; Lee, Hyungseok; Jun, Chi-Hoon; Koo, Sangmo; Ko, Sang Choon

    2016-07-01

    We present a method of forming shallow p-doping on a 4H-SiC surface by depositing a thin Al layer (d = 5 nm) and then thermally annealing it at 1000 °C for 10 min. A secondary ion mass spectrometry analysis of the annealed Al/SiC sample reveals an Al concentration in excess of 1017 cm-3 up to a depth of d ≤ 250 nm. I-V measurements and CV characterizations of Ti-SiC Schottky barrier diodes (SBDs) fabricated on a n-type SiC epi-wafer indicate that the shallow Al doping increases the built-in potential of the junction and the barrier height by Δ V b i = 0.51 eV and Δ ϕ B = 0.26 eV , respectively. Assuming a rectangular doping profile, calculations of the built-in voltage shift and the Schottky barrier height indicate that partial dopant activation (activation ratio ˜2%) can induce the observed barrier height shift. The shallow doping method was then used to fabricate junction terminations in SBDs which increased the breakdown voltage and reduced the reverse leakage current. Technology CAD simulations of the SBD with and without doping verify that a reduction of peak electric field can explain the improvement of the breakdown voltage.

  8. Quantitatively Probing the Al Distribution in Zeolites

    SciTech Connect

    Vjunov, Aleksei; Fulton, John L.; Huthwelker, Thomas; Pin, Sonia; Mei, Donghai; Schenter, Gregory K.; Govind, Niranjan; Camaioni, Donald M.; Hu, Jian Z.; Lercher, Johannes A.

    2014-06-11

    The degree of substitution of Si4+ by Al3+ in the oxygen-terminated tetrahedra (Al T-sites) of zeolites determines the concentration of ion-exchange and Brønsted acid sites. As the location of the tetrahedra and the associated subtle variations in bond angles influence the acid strength, quantitative information about Al T-sites in the framework is critical to rationalize catalytic properties and to design new catalysts. A quantitative analysis is reported that uses a combination of extended X-ray absorption fine structure (EXAFS) analysis and 27Al MAS NMR spectroscopy supported by DFT-based molecular dynamics simulations. To discriminate individual Al atoms, sets of ab initio EXAFS spectra for various T-sites are generated from DFT-based molecular dynamics simulations allowing quantitative treatment of the EXAFS single- and multiple-photoelectron scattering processes out to 3-4 atom shells surrounding the Al absorption center. It is observed that identical zeolite types show dramatically different Al-distributions. A preference of Al for T-sites that are part of one or more 4-member rings in the framework over those T-sites that are part of only 5- and 6-member rings in the HBEA150 sample has been determined from a combination of these methods. This work was supported by the U. S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.

  9. The effect of exposure to aluminium on concentrations of essential metals in serum of foundry workers.

    PubMed Central

    Röllin, H B; Theodorou, P; Kilroe-Smith, T A

    1991-01-01

    The concentrations of aluminium (Al) in serum and urine of 33 volunteers exposed to inhalation of Al2O3 dust at a concentration in the air of less than 1 mg Al/m3 were measured. These were compared with results from 20 normal subjects not exposed. The concentrations of copper (Cu), zinc (Zn), and total iron (Fe) in serum were also measured. The Al concentration in serum was significantly raised in the subjects exposed to dust, but Al concentrations in urine showed no significant difference from controls. This suggests a possible change in distribution of metals in the body tissues due to the presence of Al, with incomplete excretion of Al in the urine. This redistribution was selective, as the serum concentrations of Cu were conclusively decreased whereas the serum concentrations of Zn were conclusively increased. The serum concentration of Fe did not change significantly. PMID:2025590

  10. 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°.

  11. Magnetism in Fe4Al13 and related FeAl intermetallics

    NASA Astrophysics Data System (ADS)

    Chi, Ji; Li, Yang; Gou, Weiping; Goruganti, V.; Rathnayaka, K. D. D.; Ross, Joseph H., Jr.

    2006-03-01

    We report the results of an experimental study of FeAl alloys, including Fe4Al13, FeAl2 and Fe2Al5. By using NMR, dc magnetic susceptibility, and specific heat, we found that Fe4Al13 and Fe2Al5 are non-magnetic with some dilute magnetic moments, while FeAl2 can be characterized as a concentrated local moment syst