Chemical characteristics of submicron particles at the central Tibetan Plateau: insights from aerosol mass spectrometry

Science.gov (United States)

Xu, Jianzhong; Zhang, Qi; Shi, Jinsen; Ge, Xinlei; Xie, Conghui; Wang, Junfeng; Kang, Shichang; Zhang, Ruixiong; Wang, Yuhang

2018-01-01

Recent studies have revealed a significant influx of anthropogenic aerosol from South Asia to the Himalayas and Tibetan Plateau (TP) during pre-monsoon period. In order to characterize the chemical composition, sources, and transport processes of aerosol in this area, we carried out a field study during June 2015 by deploying a suite of online instruments including an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-AMS) and a multi-angle absorption photometer (MAAP) at Nam Co station (90°57' E, 30°46' N; 4730 m a.s.l.) at the central of the TP. The measurements were made at a period when the transition from pre-monsoon to monsoon occurred. The average ambient mass concentration of submicron particulate matter (PM1) over the whole campaign was ˜ 2.0 µg m-3, with organics accounting for 68 %, followed by sulfate (15 %), black carbon (8 %), ammonium (7 %), and nitrate (2 %). Relatively higher aerosol mass concentration episodes were observed during the pre-monsoon period, whereas persistently low aerosol concentrations were observed during the monsoon period. However, the chemical composition of aerosol during the higher aerosol concentration episodes in the pre-monsoon season was on a case-by-case basis, depending on the prevailing meteorological conditions and air mass transport routes. Most of the chemical species exhibited significant diurnal variations with higher values occurring during afternoon and lower values during early morning, whereas nitrate peaked during early morning in association with higher relative humidity and lower air temperature. Organic aerosol (OA), with an oxygen-to-carbon ratio (O / C) of 0.94, was more oxidized during the pre-monsoon period than during monsoon (average O / C ratio of 0.72), and an average O / C was 0.88 over the entire campaign period, suggesting overall highly oxygenated aerosol in the central TP. Positive matrix factorization of the high-resolution mass spectra of OA identified two oxygenated

Aerosols in the tropical and subtropical UT/LS: in-situ measurements of submicron particle abundance and volatility

Directory of Open Access Journals (Sweden)

S. Borrmann

2010-06-01

Full Text Available Processes occurring in the tropical upper troposphere (UT, the Tropical Transition Layer (TTL, and the lower stratosphere (LS are of importance for the global climate, for stratospheric dynamics and air chemistry, and for their influence on the global distribution of water vapour, trace gases and aerosols. In this contribution we present aerosol and trace gas (in-situ measurements from the tropical UT/LS over Southern Brazil, Northern Australia, and West Africa. The instruments were operated on board of the Russian high altitude research aircraft M-55 "Geophysica" and the DLR Falcon-20 during the campaigns TROCCINOX (Araçatuba, Brazil, February 2005, SCOUT-O3 (Darwin, Australia, December 2005, and SCOUT-AMMA (Ouagadougou, Burkina Faso, August 2006. The data cover submicron particle number densities and volatility from the COndensation PArticle counting System (COPAS, as well as relevant trace gases like N₂O, ozone, and CO. We use these trace gas measurements to place the aerosol data into a broader atmospheric context. Also a juxtaposition of the submicron particle data with previous measurements over Costa Rica and other tropical locations between 1999 and 2007 (NASA DC-8 and NASA WB-57F is provided. The submicron particle number densities, as a function of altitude, were found to be remarkably constant in the tropical UT/LS altitude band for the two decades after 1987. Thus, a parameterisation suitable for models can be extracted from these measurements. Compared to the average levels in the period between 1987 and 2007 a slight increase of particle abundances was found for 2005/2006 at altitudes with potential temperatures, Θ, above 430 K. The origins of this increase are unknown except for increases measured during SCOUT-AMMA. Here the eruption of the Soufrière Hills volcano in the Caribbean caused elevated particle mixing ratios. The vertical profiles from Northern hemispheric mid-latitudes between 1999 and 2006 also are

Chemical Characterization of Submicron Aerosol Particles in São Paulo, Brazil

Science.gov (United States)

Ferreira De Brito, J.; Rizzo, L. V.; Godoy, J.; Godoy, M. L.; de Assunção, J. V.; Alves, N. D.; Artaxo, P.

2013-12-01

Megacities, large urban conglomerates with a population of 10 million or more inhabitants, are increasingly receiving attention as strong pollution hotspots with significant global impact. The emissions from such large centers in both the developed and developing parts of the world are strongly impacted by the transportation sector. The São Paulo Metropolitan Area (SPMA), located in the Southeast of Brazil, is a megacity with a population of 18 million people and 7 million vehicles, many of which fuelled by a considerably amount of anhydrous ethanol. Such fleet is considered a unique case of large scale biofuel usage worldwide. Despite the large impact on human health and atmospheric chemistry/dynamics, many uncertainties are found in terms of gas and particulate matter emissions from vehicles and their atmospheric reactivity, e.g. secondary organic aerosol formation. In order to better understand aerosol life cycle on such environment, a suite of instruments for gas and particulate matter characterization has been deployed in two sampling sites within the SPMA, including an Aerosol Chemical Speciation Monitor (ACSM). The instrumentation was deployed at the rooftop of a 45m high building in the University of São Paulo during winter/spring 2012. The site is located roughly 6km downwind of the city center with little influence from local sources. The second site is located in a downtown area, sampling at the top floor of the Public Health Faculty, approximately 10m above ground. The instrumentation was deployed at the Downtown site during summer/fall 2013. The average non-refractory submicron aerosol concentration at the University site was 6.7 μg m-3, being organics the most abundant specie (70%), followed by NO3 (12%), NH4 (8%), SO4 (8%) and Chl (2%). At the Downtown site, average aerosol concentration was 15.1 μg m-3, with Organics composing 65% of the mass, followed by NH4 (12%), NO3 (11%), SO4 (11%) and Chl (1%). The analysis of specific fragmentation

Development and scintigraphic evaluation of submicron sized dry powder inhalation formulation of fluticasone propionate in healthy human volunteers

International Nuclear Information System (INIS)

Ali, Sultana S.; Ahmad, F.J.; Khar, R.K.; Rathore, V.P.; Ali, Rashid; Rawat, H.S.; Chopra, M.K.; Mittal, G.; Bhatnagar, A.

2010-01-01

Full text: Objective of the present study concerns formulation and evaluation of submicron sized dry powder inhalation formulation of Fluticasone propionate for the treatment of bronchial asthma, COPD and a new life saving treatment option in restrictive lung diseases such as Interstitial Lung Disease (ILD), toxic and non-cardiogenic pulmonary inflammations or pulmonary edema, which have no effective treatment presently. Materials and Methods: The submicron sized particles were prepared by precipitation method using acetone as solvent and water as antisolvent. Poloxamer F127 was used as stabilizer. Both submicronized and micronized particles were characterized using FTIR, XRD, DSC, SEM and TEM. The mass median aerodynamic diameter (MMAD) of the submicronized and micronized API was calculated using Andersen cascade impactor. The prepared particles and micronized Active Pharmaceutical Ingredient (API) were radiolabeled with 99m Tc. Size3 HPMC capsules were filled with the 12.5 mg radiolabeled blend (100μg Fluticasone propionate and 12.4mg inhalable lactose) and given to healthy volunteers to assess the comparative pulmonary deposition. Results: The prepared formulation has shown better lung deposition as compared to micronized API. The MMAD of submicronized particles was in the range of 1 - 5 μm while the MMAD of micronized API was in the range of 5 - 15μm. Conclusion: The developed submicron sized dry powder inhalation formulation has better lung deposition as compared to micron sized API and it will become a better treatment option for the bronchial asthma, COPD and ILDs

Volatility measurement of atmospheric submicron aerosols in an urban atmosphere in southern China

Directory of Open Access Journals (Sweden)

L.-M. Cao

2018-02-01

Full Text Available Aerosol pollution has been a very serious environmental problem in China for many years. The volatility of aerosols can affect the distribution of compounds in the gas and aerosol phases, the atmospheric fates of the corresponding components, and the measurement of the concentration of aerosols. Compared to the characterization of chemical composition, few studies have focused on the volatility of aerosols in China. In this study, a thermodenuder aerosol mass spectrometer (TD-AMS system was deployed to study the volatility of non-refractory submicron particulate matter (PM1 species during winter in Shenzhen. To our knowledge, this paper is the first report of the volatilities of aerosol chemical components based on a TD-AMS system in China. The average PM1 mass concentration during the experiment was 42.7±20.1 µg m−3, with organic aerosol (OA being the most abundant component (43.2 % of the total mass. The volatility of chemical species measured by the AMS varied, with nitrate showing the highest volatility, with a mass fraction remaining (MFR of 0.57 at 50 °C. Organics showed semi-volatile characteristics (the MFR was 0.88 at 50 °C, and the volatility had a relatively linear correlation with the TD temperature (from the ambient temperature to 200 °C, with an evaporation rate of 0.45 % °C−1. Five subtypes of OA were resolved from total OA using positive matrix factorization (PMF for data obtained under both ambient temperature and high temperatures through the TD, including a hydrocarbon-like OA (HOA, accounting for 13.5 %, a cooking OA (COA, 20.6 %, a biomass-burning OA (BBOA, 8.9 %, and two oxygenated OAs (OOAs: a less-oxidized OOA (LO-OOA, 39.1 % and a more-oxidized OOA (MO-OOA, 17.9 %. Different OA factors presented different volatilities, and the volatility sequence of the OA factors at 50 °C was HOA (MFR of 0.56  >  LO-OOA (0.70  >  COA (0.85  ≈  BBOA (0.87�

Chemical characteristics of submicron particles at the central Tibetan Plateau: insights from aerosol mass spectrometry

Directory of Open Access Journals (Sweden)

J. Xu

2018-01-01

Full Text Available Recent studies have revealed a significant influx of anthropogenic aerosol from South Asia to the Himalayas and Tibetan Plateau (TP during pre-monsoon period. In order to characterize the chemical composition, sources, and transport processes of aerosol in this area, we carried out a field study during June 2015 by deploying a suite of online instruments including an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-AMS and a multi-angle absorption photometer (MAAP at Nam Co station (90°57′ E, 30°46′ N; 4730 m a.s.l. at the central of the TP. The measurements were made at a period when the transition from pre-monsoon to monsoon occurred. The average ambient mass concentration of submicron particulate matter (PM1 over the whole campaign was  ∼  2.0 µg m−3, with organics accounting for 68 %, followed by sulfate (15 %, black carbon (8 %, ammonium (7 %, and nitrate (2 %. Relatively higher aerosol mass concentration episodes were observed during the pre-monsoon period, whereas persistently low aerosol concentrations were observed during the monsoon period. However, the chemical composition of aerosol during the higher aerosol concentration episodes in the pre-monsoon season was on a case-by-case basis, depending on the prevailing meteorological conditions and air mass transport routes. Most of the chemical species exhibited significant diurnal variations with higher values occurring during afternoon and lower values during early morning, whereas nitrate peaked during early morning in association with higher relative humidity and lower air temperature. Organic aerosol (OA, with an oxygen-to-carbon ratio (O ∕ C of 0.94, was more oxidized during the pre-monsoon period than during monsoon (average O ∕ C ratio of 0.72, and an average O ∕ C was 0.88 over the entire campaign period, suggesting overall highly oxygenated aerosol in the central TP. Positive matrix factorization of the

Long-term Chemical Characterization of Submicron Aerosol Particles in the Amazon Forest - ATTO Station

Science.gov (United States)

Carbone, S.; Brito, J.; Rizzo, L. V.; Holanda, B. A.; Cirino, G. G.; Saturno, J.; Krüger, M. L.; Pöhlker, C.; Ng, N. L.; Xu, L.; Andreae, M. O.; Artaxo, P.

2015-12-01

The study of the chemical composition of aerosol particles in the Amazon forest represents a step forward to understand the strong coupling between the atmosphere and the forest. For this reason submicron aerosol particles were investigated in the Amazon forest, where biogenic and anthropogenic aerosol particles coexist at the different seasons (wet/dry). The measurements were performed at the ATTO station, which is located about 150 km northeast of Manaus. At ATTO station the Aerosol chemical speciation monitor (ACSM, Aerodyne) and the Multiangle absorption photometer (MAAP, Thermo 5012) have been operated continuously from March 2014 to July 2015. In this study, long-term measurements (near-real-time, ~30 minutes) of PM1 chemical composition were investigated for the first time in this environment.The wet season presented lower concentrations than the dry season (~5 times). In terms of chemical composition, both seasons were dominated by organics (75 and 63%) followed by sulfate (11 and 13%). Nitrate presented different ratio values between the mass-to-charges 30 to 46 (main nitrate fragments) suggesting the presence of nitrate as inorganic and organic nitrate during both seasons. The results indicated that about 75% of the nitrate signal was from organic nitrate during the dry season. In addition, several episodes with elevated amount of chloride, likely in the form of sea-salt from the Atlantic Ocean, were observed during the wet season. During those episodes, chloride comprised up to 7% of the PM1. During the dry season, chloride was also observed; however, with different volatility, which suggested that Chloride was present in different form and source. Moreover, the constant presence of sulfate and BC during the wet season might be related to biomass burning emissions from Africa. BC concentration was 2.5 times higher during the dry season. Further characterization of the organic fraction was accomplished with the positive matrix factorization (PMF), which

Modelling size and structure of nanoparticles formed from drying of submicron solution aerosols

International Nuclear Information System (INIS)

Bandyopadhyay, Arpan A.; Pawar, Amol A.; Venkataraman, Chandra; Mehra, Anurag

2015-01-01

Drying of submicron solution aerosols, under controlled conditions, has been explored to prepare nanoparticles for drug delivery applications. A computational model of solution drop evaporation is developed to study the evolution of solute gradients inside the drop and predict the size and shell thickness of precipitating nanoparticles. The model considers evaporation as a two-stage process involving droplet shrinkage and shell growth. It was corroborated that droplet evaporation rate controls the solute distribution within a droplet and the resulting particle structure (solid or shell type). At higher gas temperatures, rapid build-up of solute near drop surface from high evaporation rates results in early attainment of critical supersaturation solubility and a steeper solute gradient, which favours formation of larger, shell-type particles. At lower gas temperatures, formation of smaller, solid nanoparticles is indicated. The computed size and shell thickness are in good agreement with experimentally prepared lipid nanoparticles. This study indicates that solid or shell structure of precipitated nanoparticles is strongly affected by evaporation rate, while initial solute concentration in the precursor solution and atomized droplet size affect shell thickness. For the gas temperatures considered, evaporative cooling leads to droplet temperature below the melting point of the lipid solute. Thus, we conclude that control over nanoparticle size and structure, of thermolabile precursor materials suitable for drug delivery, can be achieved by controlling evaporation rates, through selection of aerosol processing conditions

Modelling size and structure of nanoparticles formed from drying of submicron solution aerosols

Energy Technology Data Exchange (ETDEWEB)

Bandyopadhyay, Arpan A.; Pawar, Amol A.; Venkataraman, Chandra; Mehra, Anurag, E-mail: mehra@iitb.ac.in [Indian Institute of Technology Bombay, Department of Chemical Engineering (India)

2015-01-15

Drying of submicron solution aerosols, under controlled conditions, has been explored to prepare nanoparticles for drug delivery applications. A computational model of solution drop evaporation is developed to study the evolution of solute gradients inside the drop and predict the size and shell thickness of precipitating nanoparticles. The model considers evaporation as a two-stage process involving droplet shrinkage and shell growth. It was corroborated that droplet evaporation rate controls the solute distribution within a droplet and the resulting particle structure (solid or shell type). At higher gas temperatures, rapid build-up of solute near drop surface from high evaporation rates results in early attainment of critical supersaturation solubility and a steeper solute gradient, which favours formation of larger, shell-type particles. At lower gas temperatures, formation of smaller, solid nanoparticles is indicated. The computed size and shell thickness are in good agreement with experimentally prepared lipid nanoparticles. This study indicates that solid or shell structure of precipitated nanoparticles is strongly affected by evaporation rate, while initial solute concentration in the precursor solution and atomized droplet size affect shell thickness. For the gas temperatures considered, evaporative cooling leads to droplet temperature below the melting point of the lipid solute. Thus, we conclude that control over nanoparticle size and structure, of thermolabile precursor materials suitable for drug delivery, can be achieved by controlling evaporation rates, through selection of aerosol processing conditions.

Sources and Characterization of Submicron Aerosols in a Rural Forest During the PROPHET-AMOS 2016 Campaign

Science.gov (United States)

Bui, A. T.; Wallace, H. W., IV; Alvarez, S. L.; Erickson, M.; Alwe, H. D.; May, N.; Cook, R.; Connor, M.; Slade, J. H., Jr.; Shi, Q.; Kavassalis, S.; Tyndall, G. S.; Shepson, P. B.; Pratt, K.; Ault, A. P.; Millet, D. B.; Murphy, J. G.; Usenko, S.; Sheesley, R. J.; Flynn, J. H., III; Griffin, R. J.; Wang, W.

2017-12-01

Forests are a rich source of biogenic volatile organic compounds (BVOCs). Oxidation of BVOCs can result in the formation of secondary organic aerosol (SOA) and in the presence of NOx (NO+NO2) produce organic nitrate-containing particles. However, the distribution of both BVOCs and oxidants can be dramatically altered by the physical barriers provided by a forest canopy. Global models currently neglect the effect of these canopies on SOA formation in forested regions. In this work, we characterize non-refractory submicron aerosol (NR-PM1) using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) during the 2016 Program on Oxidants: Photochemistry, Emissions, and Transport-Atmospheric Measurements of Oxidants in Summer (PROPHET-AMOS) campaign. This site is located in a rural forest in northern Michigan and features a tower that allowed for both above and below canopy measurements. Our results indicate that organic aerosols (OA) account for a substantial portion of the NR-PM1 measured at this site. Organic nitrate aerosol can contribute up to 18% of the total OA and an average of 75% of the total measured nitrate aerosol. Episodes of above- and below-canopy NR-PM1 concentration differences indicate that above-canopy OA concentrations can be up to 40% greater than below-canopy, which represents an increase of up to 1.5 µg/m3. Organic fragment ions such as CxHy, CxHyOz, and CxHyO1 contribute to enhanced above-canopy OA concentrations. Positive matrix factorization analysis of the high-resolution OA mass spectra identified three SOA factors: low volatility oxygenated OA (LVOOA), isoprene-derived OOA (ISOOA), and oxygenated organic aerosol. Analysis of air mass backward trajectories and correlations with external data indicate that LVOOA correlates well with sulfate and aged, urban-influenced air masses, whereas ISOOA correlates well with isoprene SOA tracers and air masses originating from semi-remote areas. Our results indicate that the OA at this

Combustion aerosols from potassium-containing fuels

Energy Technology Data Exchange (ETDEWEB)

Balzer Nielsen, Lars

1999-12-31

The scope of the work presented in this thesis is the formation and evolution of aerosol particles in the submicron range during combustion processes, in particular where biomass is used alone or co-fired with coal. An introduction to the formation processes of fly ash in general and submicron aerosol in particular during combustion is presented, along with some known problems related to combustion of biomass for power generation. The work falls in two parts. The first is the design of a laboratory setup for investigation of homogeneous nucleation and particle dynamics at high temperature. The central unit of the setup is a laminar flow aerosol condenser (LFAC), which essentially is a 173 cm long tubular furnace with an externally cooled wall. A mathematical model is presented which describes the formation and evolution of the aerosol in the LFAC, where the rate of formation of new nuclei is calculated using the so-called classical theory. The model includes mass and energy conservation equations and an expression for the description of particle growth by diffusion. The resulting set of nonlinear second-order partial differential equations are solved numerically using the method of orthogonal collocation. The model is implemented in the FORTRAN code MONAERO. The second part of this thesis describes a comprehensive investigation of submicron aerosol formation during co-firing of coal and straw carried out at a 380 MW{sub Th} pulverized coal unit at Studstrup Power Plant, Aarhus. Three types of coal are used, and total boiler load and straw input is varied systematically. Straw contains large amounts of potassium, which is released during combustion. Submicron aerosol is sampled between the two banks of the economizer at a flue gas temperature of 350 deg. C using a novel ejector probe. The aerosol is characterized using the SMPS system and a Berner-type low pressure impactor. The chemical composition of the particles collected in the impactor is determined using

Combustion aerosols from potassium-containing fuels

International Nuclear Information System (INIS)

Balzer Nielsen, Lars

1998-01-01

The scope of the work presented in this thesis is the formation and evolution of aerosol particles in the submicron range during combustion processes, in particular where biomass is used alone or co-fired with coal. An introduction to the formation processes of fly ash in general and submicron aerosol in particular during combustion is presented, along with some known problems related to combustion of biomass for power generation. The work falls in two parts. The first is the design of a laboratory setup for investigation of homogeneous nucleation and particle dynamics at high temperature. The central unit of the setup is a laminar flow aerosol condenser (LFAC), which essentially is a 173 cm long tubular furnace with an externally cooled wall. A mathematical model is presented which describes the formation and evolution of the aerosol in the LFAC, where the rate of formation of new nuclei is calculated using the so-called classical theory. The model includes mass and energy conservation equations and an expression for the description of particle growth by diffusion. The resulting set of nonlinear second-order partial differential equations are solved numerically using the method of orthogonal collocation. The model is implemented in the FORTRAN code MONAERO. The second part of this thesis describes a comprehensive investigation of submicron aerosol formation during co-firing of coal and straw carried out at a 380 MW Th pulverized coal unit at Studstrup Power Plant, Aarhus. Three types of coal are used, and total boiler load and straw input is varied systematically. Straw contains large amounts of potassium, which is released during combustion. Submicron aerosol is sampled between the two banks of the economizer at a flue gas temperature of 350 deg. C using a novel ejector probe. The aerosol is characterized using the SMPS system and a Berner-type low pressure impactor. The chemical composition of the particles collected in the impactor is determined using chemical

Combustion aerosols from potassium-containing fuels

Energy Technology Data Exchange (ETDEWEB)

Balzer Nielsen, Lars

1998-12-31

The scope of the work presented in this thesis is the formation and evolution of aerosol particles in the submicron range during combustion processes, in particular where biomass is used alone or co-fired with coal. An introduction to the formation processes of fly ash in general and submicron aerosol in particular during combustion is presented, along with some known problems related to combustion of biomass for power generation. The work falls in two parts. The first is the design of a laboratory setup for investigation of homogeneous nucleation and particle dynamics at high temperature. The central unit of the setup is a laminar flow aerosol condenser (LFAC), which essentially is a 173 cm long tubular furnace with an externally cooled wall. A mathematical model is presented which describes the formation and evolution of the aerosol in the LFAC, where the rate of formation of new nuclei is calculated using the so-called classical theory. The model includes mass and energy conservation equations and an expression for the description of particle growth by diffusion. The resulting set of nonlinear second-order partial differential equations are solved numerically using the method of orthogonal collocation. The model is implemented in the FORTRAN code MONAERO. The second part of this thesis describes a comprehensive investigation of submicron aerosol formation during co-firing of coal and straw carried out at a 380 MW{sub Th} pulverized coal unit at Studstrup Power Plant, Aarhus. Three types of coal are used, and total boiler load and straw input is varied systematically. Straw contains large amounts of potassium, which is released during combustion. Submicron aerosol is sampled between the two banks of the economizer at a flue gas temperature of 350 deg. C using a novel ejector probe. The aerosol is characterized using the SMPS system and a Berner-type low pressure impactor. The chemical composition of the particles collected in the impactor is determined using

Aerosol Chemical Speciation Monitor (ACSM) Instrument Handbook

Energy Technology Data Exchange (ETDEWEB)

Watson, Thomas B. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2017-08-15

The Aerodyne Aerosol Chemical Speciation Monitor (ACSM) measures particle mass loading and chemical composition in real time for non-refractory sub-micron aerosol particles. The ACSM is designed for long-term unattended deployment and routine monitoring applications.

Number Size Distributions and Seasonality of Submicron Particles in Europe 2008–2009

Czech Academy of Sciences Publication Activity Database

Asmi, A.; Wiedensohler, A.; Laj, P.; Fjaeraa, A.-M.; Sellegri, K.; Birmili, W.; Weingartner, E.; Baltensperger, U.; Ždímal, Vladimír; Zíková, Naděžda; Putaud, J.-P.; Marioni, A.; Tunved, P.; Hansson, H.-C.; Fiebig, M.; Kivekäs, N.; Lihavainen, H.; Asmi, E.; Ulevicius, V.; Aalto, P.P.; Swietlicki, E.; Kristensson, E.; Mihalopoulos, N.; Kalivitis, N.; Kalapov, I.; Kiss, G.; de Leeuw, G.; Henzig, B.; Harrison, R. M.; Beddows, D.; O´Dowd, C.; Jennings, S.G.; Flentje, H.; Weinhold, K.; Meinhardt, F.; Ries, L.; Kulmala, M.

2011-01-01

Roč. 11, - (2011), s. 5505-5538 ISSN 1680-7316 EU Projects: European Commission(XE) RII3-CT-2006-026140; European Commission(XE) 36833; European Commission(IT) Ev-K2-CNR Grant - others:AFCE(FI) 1118615 Program:FP6 Institutional research plan: CEZ:AV0Z40720504 Keywords : aerosol particle number * aerosol concentrations * european submicron Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.520, year: 2011

AIP1OGREN: Aerosol Observing Station Intensive Properties Value-Added Product

Energy Technology Data Exchange (ETDEWEB)

Koontz, Annette [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Flynn, Connor [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2017-09-15

The aip1ogren value-added product (VAP) computes several aerosol intensive properties. It requires as input calibrated, corrected, aerosol extensive properties (scattering and absorption coefficients, primarily) from the Aerosol Observing Station (AOS). Aerosol extensive properties depend on both the nature of the aerosol and the amount of the aerosol. We compute several properties as relationships between the various extensive properties. These intensive properties are independent of aerosol amount and instead relate to intrinsic properties of the aerosol itself. Along with the original extensive properties we report aerosol single-scattering albedo, hemispheric backscatter fraction, asymmetry parameter, and Ångström exponent for scattering and absorption with one-minute averaging. An hourly averaged file is produced from the 1-minute files that includes all extensive and intensive properties as well as submicron scattering and submicron absorption fractions. Finally, in both the minutely and hourly files the aerosol radiative forcing efficiency is provided.

The attachment of radon daughters to submicron aerosol particles

International Nuclear Information System (INIS)

Grenier, M.G.; Bigu, J.

1984-04-01

A study of the effects of aerosol concentration, aerosol size distribution and relative humidity on the Working Level and the radon daughter concentration was conducted in a 3000 L radon environmental chamber. Typical values of the aerosol concentration varied in the 1 x 10 3 particles/cm 3 to 4.5 x 10 5 particles/cm 3 range. Various size distributions of aerosols that have mean diffusional aerodynamic diameters of .025 μm, .045 μm and .090 μm were tested. A good correlation was found between the Working Level and the aerosol concentration as well as the relative humidity. Most of the activity seems to be associated with particles of diameter between .05 μm and .2 μm. The results presented here are in agreement with work done by other investigators in the health physics field

Aerosol filtration with metallic fibrous filters

International Nuclear Information System (INIS)

Klein, M.; Goossens, W.R.A.

1983-01-01

The filtration efficiency of stainless steel fibrous filters (BEKIPOR porous mats and sintered webs) is determined using submicronic monodisperse polystyrene aerosols. Lasers spectrometers are used for the aerosol measurements. The parameters varied are the fiber diameter, the number of layers, the aerosol diameter and the superficial velocity. Two selected types of filters are tested with polydisperse methylene blue aerosols to determine the effect of bed loading on the filter performance and to test washing techniques for the regeneration of the filter

Black carbon aerosol mixing state, organic aerosols and aerosol optical properties over the UK

Science.gov (United States)

McMeeking, G. R.; Morgan, W. T.; Flynn, M.; Highwood, E. J.; Turnbull, K.; Haywood, J.; Coe, H.

2011-05-01

Black carbon (BC) aerosols absorb sunlight thereby leading to a positive radiative forcing and a warming of climate and can also impact human health through their impact on the respiratory system. The state of mixing of BC with other aerosol species, particularly the degree of internal/external mixing, has been highlighted as a major uncertainty in assessing its radiative forcing and hence its climate impact, but few in situ observations of mixing state exist. We present airborne single particle soot photometer (SP2) measurements of refractory BC (rBC) mass concentrations and mixing state coupled with aerosol composition and optical properties measured in urban plumes and regional pollution over the UK. All data were obtained using instrumentation flown on the UK's BAe-146-301 large Atmospheric Research Aircraft (ARA) operated by the Facility for Airborne Atmospheric Measurements (FAAM). We measured sub-micron aerosol composition using an aerosol mass spectrometer (AMS) and used positive matrix factorization to separate hydrocarbon-like (HOA) and oxygenated organic aerosols (OOA). We found a higher number fraction of thickly coated rBC particles in air masses with large OOA relative to HOA, higher ozone-to-nitrogen oxides (NOx) ratios and large concentrations of total sub-micron aerosol mass relative to rBC mass concentrations. The more ozone- and OOA-rich air masses were associated with transport from continental Europe, while plumes from UK cities had higher HOA and NOx and fewer thickly coated rBC particles. We did not observe any significant change in the rBC mass absorption efficiency calculated from rBC mass and light absorption coefficients measured by a particle soot absorption photometer despite observing significant changes in aerosol composition and rBC mixing state. The contributions of light scattering and absorption to total extinction (quantified by the single scattering albedo; SSA) did change for different air masses, with lower SSA observed in

Seasonal characterization of submicron aerosol chemical composition and organic aerosol sources in the southeastern United States: Atlanta, Georgia,and Look Rock, Tennessee

Directory of Open Access Journals (Sweden)

S. H. Budisulistiorini

2016-04-01

Full Text Available A year-long near-real-time characterization of non-refractory submicron aerosol (NR-PM1 was conducted at an urban (Atlanta, Georgia, in 2012 and rural (Look Rock, Tennessee, in 2013 site in the southeastern US using the Aerodyne Aerosol Chemical Speciation Monitor (ACSM collocated with established air-monitoring network measurements. Seasonal variations in organic aerosol (OA and inorganic aerosol species are attributed to meteorological conditions as well as anthropogenic and biogenic emissions in this region. The highest concentrations of NR-PM1 were observed during winter and fall seasons at the urban site and during spring and summer at the rural site. Across all seasons and at both sites, NR-PM1 was composed largely of OA (up to 76 % and sulfate (up to 31 %. Six distinct OA sources were resolved by positive matrix factorization applied to the ACSM organic mass spectral data collected from the two sites over the 1 year of near-continuous measurements at each site: hydrocarbon-like OA (HOA, biomass burning OA (BBOA, semi-volatile oxygenated OA (SV-OOA, low-volatility oxygenated OA (LV-OOA, isoprene-derived epoxydiols (IEPOX OA (IEPOX-OA and 91Fac (a factor dominated by a distinct ion at m∕z 91 fragment ion previously observed in biogenic influenced areas. LV-OOA was observed throughout the year at both sites and contributed up to 66 % of total OA mass. HOA was observed during the entire year only at the urban site (on average 21 % of OA mass. BBOA (15–33 % of OA mass was observed during winter and fall, likely dominated by local residential wood burning emission. Although SV-OOA contributes quite significantly ( ∼  27 %, it was observed only at the urban site during colder seasons. IEPOX-OA was a major component (27–41 % of OA at both sites, particularly in spring and summer. An ion fragment at m∕z 75 is well correlated with the m∕z 82 ion associated with the aerosol mass spectrum of IEPOX

Black carbon aerosol mixing state, organic aerosols and aerosol optical properties over the United Kingdom

Science.gov (United States)

McMeeking, G. R.; Morgan, W. T.; Flynn, M.; Highwood, E. J.; Turnbull, K.; Haywood, J.; Coe, H.

2011-09-01

Black carbon (BC) aerosols absorb sunlight thereby leading to a positive radiative forcing and a warming of climate and can also impact human health through their impact on the respiratory system. The state of mixing of BC with other aerosol species, particularly the degree of internal/external mixing, has been highlighted as a major uncertainty in assessing its radiative forcing and hence its climate impact, but few in situ observations of mixing state exist. We present airborne single particle soot photometer (SP2) measurements of refractory BC (rBC) mass concentrations and mixing state coupled with aerosol composition and optical properties measured in urban plumes and regional pollution over the United Kingdom. All data were obtained using instrumentation flown on the UK's BAe-146-301 large Atmospheric Research Aircraft (ARA) operated by the Facility for Airborne Atmospheric Measurements (FAAM). We measured sub-micron aerosol composition using an aerosol mass spectrometer (AMS) and used positive matrix factorization to separate hydrocarbon-like (HOA) and oxygenated organic aerosols (OOA). We found a higher number fraction of thickly coated rBC particles in air masses with large OOA relative to HOA, higher ozone-to-nitrogen oxides (NOx) ratios and large concentrations of total sub-micron aerosol mass relative to rBC mass concentrations. The more ozone- and OOA-rich air masses were associated with transport from continental Europe, while plumes from UK cities had higher HOA and NOx and fewer thickly coated rBC particles. We did not observe any significant change in the rBC mass absorption efficiency calculated from rBC mass and light absorption coefficients measured by a particle soot absorption photometer despite observing significant changes in aerosol composition and rBC mixing state. The contributions of light scattering and absorption to total extinction (quantified by the single scattering albedo; SSA) did change for different air masses, with lower SSA

Black carbon aerosol mixing state, organic aerosols and aerosol optical properties over the United Kingdom

Directory of Open Access Journals (Sweden)

G. R. McMeeking

2011-09-01

Full Text Available Black carbon (BC aerosols absorb sunlight thereby leading to a positive radiative forcing and a warming of climate and can also impact human health through their impact on the respiratory system. The state of mixing of BC with other aerosol species, particularly the degree of internal/external mixing, has been highlighted as a major uncertainty in assessing its radiative forcing and hence its climate impact, but few in situ observations of mixing state exist. We present airborne single particle soot photometer (SP2 measurements of refractory BC (rBC mass concentrations and mixing state coupled with aerosol composition and optical properties measured in urban plumes and regional pollution over the United Kingdom. All data were obtained using instrumentation flown on the UK's BAe-146-301 large Atmospheric Research Aircraft (ARA operated by the Facility for Airborne Atmospheric Measurements (FAAM. We measured sub-micron aerosol composition using an aerosol mass spectrometer (AMS and used positive matrix factorization to separate hydrocarbon-like (HOA and oxygenated organic aerosols (OOA. We found a higher number fraction of thickly coated rBC particles in air masses with large OOA relative to HOA, higher ozone-to-nitrogen oxides (NO_x ratios and large concentrations of total sub-micron aerosol mass relative to rBC mass concentrations. The more ozone- and OOA-rich air masses were associated with transport from continental Europe, while plumes from UK cities had higher HOA and NO_x and fewer thickly coated rBC particles. We did not observe any significant change in the rBC mass absorption efficiency calculated from rBC mass and light absorption coefficients measured by a particle soot absorption photometer despite observing significant changes in aerosol composition and rBC mixing state. The contributions of light scattering and absorption to total extinction (quantified by the single scattering albedo; SSA did change for

Airborne measurement of submicron aerosol number concentration and CCN activity in and around the Korean Peninsula and their comparison to ground measurement in Seoul

Science.gov (United States)

Park, M.; Kim, N.; Yum, S. S.

2016-12-01

Aerosols exert impact not only on human health and visibility but also on climate change directly by scattering or absorbing solar radiation and indirectly by acting as cloud condensation nuclei (CCN) and thus altering cloud radiative and microphysical properties. Aerosol indirect effects on climate has been known to have large uncertainty because of insufficient measurement data on aerosol and CCN activity distribution. Submicron aerosol number concentration (NCN, TSI CPC) and CCN number concentration (NCCN, DMT CCNC) were measured on board the NASA DC-8 research aircraft and at a ground site at Olympic Park in Seoul from May 2nd to June 10th, 2016. CCNC on the airborne platform was operated with the fixed internal supersaturation of 0.6% and CCNC at the ground site was operated with the five different supersaturations (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%). The NASA DC-8 conducted 20 research flights (about 150 hours) in and around the Korean Peninsula and the ground measurement at Olympic Park was continuously made during the measurement period. Both airborne and ground measurements showed spatially and temporally varied aerosol number concentration and CCN activity. Aerosol number concentration in the boundary layer measured on airborne platform was highly affected by pollution sources on the ground. The average diurnal distribution of ground aerosol number concentration showed distinct peaks are located at about 0800, 1500, and 2000. The middle peak indicates that new particle formation events frequently occurred during the measurement period. CCN activation ratio at 0.6% supersaturation (NCCN/NCN) of the airborne measurement ranged from 0.1 to 0.9, indicating that aerosol properties in and around the Korean Peninsula varied so much (e. g. size, hygroscopicity). Comprehensive analysis results will be shown at the conference.

Seasonal Variations of High Time-Resolved Chemical Compositions, Sources and Evolution for Atmospheric Submicron Aerosols in the Megacity of Beijing

Science.gov (United States)

Hu, Min; Hu, Wei; Hu, Weiwei; Zheng, Jing; Guo, Song; Wu, Yusheng; Lu, Sihua; Zeng, Limin

2016-04-01

This study aims to investigate aerosol secondary formation and aging process in the megacity of Beijing. Seasonal intensive campaigns were conducted from March 2012 to March 2013 at an urban site located at the campus of Peking University (116.31° E, 37.99° N). An Aerodyne high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS) and other relevant instrumentations for gaseous and particulate pollutants were deployed. The average submicron aerosol (PM1) mass concentrations were 45.1 ± 45.8, 37.5 ± 31.0, 41.3 ± 42.7 and 81.7 ± 72.4 μg m-3 in spring, summer, autumn and winter, respectively. Organic matter was the most abundant component, accounting for 31%, 33%, 44% and 36% in PM1 correspondingly, followed by sulfate and nitrate. Distinct seasonal and diurnal patterns of the components of PM1 tracking primary sources (e.g., BC and HOA) and secondary formation (e.g., sulfate, nitrate, ammonium, LV-OOA and SV-OOA) were significantly influenced by primary emissions and mesoscale meteorology. Combining positive matrix factorization (PMF) analysis with the mass spectrometry of organics measured by AMS, the contributions of primary and secondary sources to submicron organic aerosols (OA) were apportioned. In spring and summer, the primary sources were hydrocarbon-like OA (HOA) and cooking OA (COA), and the secondary components were low volatility (LV-OOA) and semi-volatile oxygenated OA (SV-OOA). In winter biomass burning OA (BBOA) was also resolved. In autumn, four factors were resolved, that is, OOA, HOA, COA and BBOA. In general, OOA (sum of LV-OOA and SV-OOA) was important in OA in four seasons, accounting for about 63%, 70%, 47% and 50%, respectively. SV-OOA dominated OA in summer (44%) due to the fresh secondary formation from strong photochemical oxidations; whereas, LV-OOA was dominant in OA in winter (33%), maybe because the transported air masses were more aged in heavily polluted days. The POA (sum of HOA, COA and BBOA) in OA was dominant in

Chemical composition and characteristics of ambient aerosols and rainwater residues during Indian summer monsoon: Insight from aerosol mass spectrometry

Science.gov (United States)

Chakraborty, Abhishek; Gupta, Tarun; Tripathi, Sachchida N.

2016-07-01

Real time composition of non-refractory submicron aerosol (NR-PM1) is measured via Aerosol mass spectrometer (AMS) for the first time during Indian summer monsoon at Kanpur, a polluted urban location located at the heart of Indo Gangetic Plain (IGP). Submicron aerosols are found to be dominated by organics followed by nitrate. Source apportionment of organic aerosols (OA) via positive matrix factorization (PMF) revealed several types of secondary/oxidized and primary organic aerosols. On average, OA are completely dominated by oxidized OA with a very little contribution from biomass burning OA. During rain events, PM1 concentration is decreased almost by 60%, but its composition remains nearly the same. Oxidized OA showed slightly more decrease than primary OAs, probably due to their higher hygroscopicity. The presence of organo nitrates (ON) is also detected in ambient aerosols. Apart from real-time sampling, collected fog and rainwater samples were also analyzed via AMS in offline mode and in the ICP-OES (Inductively coupled plasma - Optical emission spectrometry) for elements. The presence of sea salt, organo nitrates and sulfates has been observed. Rainwater residues are also dominated by organics but their O/C ratios are 15-20% lower than the observed values for ambient OA. Alkali metals such as Ca, Na, K are found to be most abundant in the rainwater followed by Zn. Rainwater residues are also found to be much less oxidized than the aerosols present inside the fog water, indicating presence of less oxidized organics. These findings indicate that rain can act as an effective scavenger of different types of pollutants even for submicron particle range. Rainwater residues also contain organo sulfates which indicate that some portion of the dissolved aerosols has undergone aqueous processing, possibly inside the cloud. Highly oxidized and possibly hygroscopic OA during monsoon period compared to other seasons (winter, post monsoon), indicates that they can act

Physical properties of aerosols at Maitri, Antarctica

Indian Academy of Sciences (India)

Measurements of the submicron aerosol size distribution made at the Indian Antarctic station, Maitri (70° 45′S, 11° 44′E) from January 10th to February 24th, 1997, are reported. Total aerosol concentrations normally range from 800 to 1200 particles cm-3 which are typical values for the coastal stations at Antarctica in ...

Submicron aerosol organic functional groups, ions, and water content at the Centreville SEARCH site (Alabama), during SOAS campaign

Science.gov (United States)

Ruggeri, G.; Ergin, G.; Modini, R. L.; Takahama, S.

2013-12-01

The SOAS campaign was conducted from June 1 to July 15 of 2013 in order to understand the relationship between biogenic and anthropogenic emissions in the South East US1,2. In this study, the organic and inorganic composition of submicron aerosol in the Centreville SEARCH site was measured by Fourier Transform Infrared Spectroscopy (FTIR) and the Ambient Ion Monitor (AIM; URG Corporation), whereas the aerosol water content was measured with a Dry Ambient Aerosol Size Spectrometer (DAASS)3. Organic functional group analysis was performed on PM1 aerosol selected by cyclone and collected on teflon filters with a time resolution of 4-12 hours, using one inlet heated to 50 °C and the other operated either at ambient temperature or 70 °C 4. The AIM measured both condensed and gas phase composition with a time resolution of 1 hour, providing partitioning behavior of inorganic species such as NH3/NH4+, HNO3/NO3-. These measurements collectively permit calculation of pure-component vapor pressures of candidate organic compounds and activity coefficients of interacting components in the condensed phase, using models such as SIMPOL.15, E-AIM6, and AIOMFAC7. From these results, the water content of the aerosol is predicted, and a comparison between modeled and measured partitioning of inorganic compounds and water vapor are discussed, in addition to organic aerosol volatility prediction based on functional group analysis. [1]- Goldstein, A.H., et al., Biogenic carbon and anthropogenic pollutants combine to form a cooling haze over the southeastern United States. Proceedings of the National Academy of Sciences of the United States of America, 2009. 106(22), 8835-8840. [2]- Carlton, A.G., Turpin, B.J., 2013. Particle partitioning potential of organic compounds is highest in the Eastern US and driven by anthropogenic water. Atmospheric Chemistry and Physics Discussions 13, 12743-12770. [3]- Khlystov, A., Stanier, C.O., Takahama, S., Pandis, S.N., 2005. Water content of ambient

Theoretical studies on aerosol agglomeration processes

Energy Technology Data Exchange (ETDEWEB)

Lehtinen, K.E.J. [VTT Energy, Espoo (Finland). Energy Use

1997-12-31

In this thesis, theoretical modeling of certain aerosol systems has been presented. At first, the aerosol general dynamic equation is introduced, along with a discretization routine for its numerical solution. Of the various possible phenomena affecting aerosol behaviour, this work is mostly focused on aerosol agglomeration. The fundamentals of aerosol agglomeration theory are thus briefly reviewed. The two practical applications of agglomeration studied in this thesis are flue gas cleaning using an electrical agglomerator and nanomaterial synthesis with a free jet reactor. In an electrical agglomerator the aerosol particles are charged and brought into an alternating electric field. The aim is to remove submicron particles from flue gases by collisions with larger particles before conventional gas cleaning devices that have a clear penetration window in the problematic 0.1-1{mu}m size range. A mathematical model was constructed to find out the effects of the different system parameters on the agglomerator`s performance. A crucial part of this task was finding out the collision efficiencies of particles of varying size and charge. The original idea was to use unipolar charging of the particles, and a laboratory scale apparatus was constructed for this purpose. Both theory and experiments clearly show that significant removal of submicron particles can not be achieved by such an arrangement. The theoretical analysis further shows that if the submicron particles and the large collector particles were charged with opposite polarity, significant removal of the submicron particles could be obtained. The second application of agglomeration considered in this thesis is predicting/controlling nanoparticle size in the gas-to-particle aerosol route to material synthesis. In a typical material reactor, a precursor vapor reacts to form molecules of the desired material. In a cooling environment, a particulate phase forms, the dynamics of which are determined by the rates of

Theoretical studies on aerosol agglomeration processes

Energy Technology Data Exchange (ETDEWEB)

Lehtinen, K E.J. [VTT Energy, Espoo (Finland). Energy Use

1998-12-31

In this thesis, theoretical modeling of certain aerosol systems has been presented. At first, the aerosol general dynamic equation is introduced, along with a discretization routine for its numerical solution. Of the various possible phenomena affecting aerosol behaviour, this work is mostly focused on aerosol agglomeration. The fundamentals of aerosol agglomeration theory are thus briefly reviewed. The two practical applications of agglomeration studied in this thesis are flue gas cleaning using an electrical agglomerator and nanomaterial synthesis with a free jet reactor. In an electrical agglomerator the aerosol particles are charged and brought into an alternating electric field. The aim is to remove submicron particles from flue gases by collisions with larger particles before conventional gas cleaning devices that have a clear penetration window in the problematic 0.1-1{mu}m size range. A mathematical model was constructed to find out the effects of the different system parameters on the agglomerator`s performance. A crucial part of this task was finding out the collision efficiencies of particles of varying size and charge. The original idea was to use unipolar charging of the particles, and a laboratory scale apparatus was constructed for this purpose. Both theory and experiments clearly show that significant removal of submicron particles can not be achieved by such an arrangement. The theoretical analysis further shows that if the submicron particles and the large collector particles were charged with opposite polarity, significant removal of the submicron particles could be obtained. The second application of agglomeration considered in this thesis is predicting/controlling nanoparticle size in the gas-to-particle aerosol route to material synthesis. In a typical material reactor, a precursor vapor reacts to form molecules of the desired material. In a cooling environment, a particulate phase forms, the dynamics of which are determined by the rates of

Springtime variations of organic and inorganic constituents in submicron aerosols (PM1.0) from Cape Hedo, Okinawa

Science.gov (United States)

Kunwar, Bhagawati; Torii, K.; Zhu, Chunmao; Fu, Pingqing; Kawamura, Kimitaka

2016-04-01

During the spring season with enhanced Asian outflow, we collected submicron aerosol (PM1.0) samples at Cape Hedo, Okinawa Island in the western North Pacific Rim. We analyzed the filter samples for diacids, oxoacids, pyruvic acid, α-dicarbonyls and fatty acids to better understand the sources and atmospheric processes in the outflow regions of Asian pollutants. Molecular distributions of diacids show a predominance of oxalic acid (C2) followed by malonic (C3) and succinic (C4) acids. Total diacids strongly correlated with secondary source tracers such as SO42- (r = 0.87), NH4+ (0.90) and methanesulfonate (MSA-) (0.84), suggesting that diacids are secondarily formed from their precursor compounds. We also found good correlations among C2, organic carbon (OC) and elemental carbon (EC) in the Okinawa aerosols, suggesting that diacids are mainly derived from anthropogenic sources. However, a weak correlation of diacids with levoglucosan, a biomass burning tracer, suggests that biomass buring is not the main source of diacids, rather diacids are secondarily formed by photochemical oxidation of organic precursors derived from fossil fuel combustion. We found a strong correlation (r = 0.98) between inorganic nitrogen (NO3-N + NH4-N) and total nitrogen (TN), to which organic nitrogen (ON) contributed 23%. Fatty acids were characterized by even carbon number predominance, suggesting that they are derived from biogenic sources. The higher abundances of short chain fatty acids (C20) further suggest that fatty acids are largely derived from marine phytoplankton during spring bloom.

Highly time-resolved chemical characterization of atmospheric submicron particles during 2008 Beijing Olympic Games using an Aerodyne High-Resolution Aerosol Mass Spectrometer

Directory of Open Access Journals (Sweden)

X.-F. Huang

2010-09-01

Full Text Available As part of Campaigns of Air Quality Research in Beijing and Surrounding Region-2008 (CAREBeijing-2008, an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS was deployed in urban Beijing to characterize submicron aerosol particles during the time of 2008 Beijing Olympic Games and Paralympic Games (24 July to 20 September 2008. The campaign mean PM₁ mass concentration was 63.1 ± 39.8 μg m⁻³; the mean composition consisted of organics (37.9%, sulfate (26.7%, ammonium (15.9%, nitrate (15.8%, black carbon (3.1%, and chloride (0.87%. The average size distributions of the species (except BC were all dominated by an accumulation mode peaking at about 600 nm in vacuum aerodynamic diameter, and organics was characterized by an additional smaller mode extending below 100 nm. Positive Matrix Factorization (PMF analysis of the high resolution organic mass spectral dataset differentiated the organic aerosol into four components, i.e., hydrocarbon-like (HOA, cooking-related (COA, and two oxygenated organic aerosols (OOA-1 and OOA-2, which on average accounted for 18.1, 24.4, 33.7 and 23.7% of the total organic mass, respectively. The HOA was identified to be closely associated with primary combustion sources, while the COA mass spectrum and diurnal pattern showed similar characteristics to that measured for cooking emissions. The OOA components correspond to aged secondary organic aerosol. Although the two OOA components have similar elemental (O/C, H/C compositions, they display differences in mass spectra and time series which appear to correlate with the different source regions sampled during the campaign. Back trajectory clustering analysis indicated that the southerly air flows were associated with the highest PM₁ pollution during the campaign. Aerosol particles in southern airmasses were especially rich in inorganic and oxidized organic species. Aerosol particles in northern airmasses

Highly time-resolved chemical characterization of atmospheric submicron particles during 2008 Beijing Olympic Games using an Aerodyne High-Resolution Aerosol Mass Spectrometer

Science.gov (United States)

Huang, X.-F.; He, L.-Y.; Hu, M.; Canagaratna, M. R.; Sun, Y.; Zhang, Q.; Zhu, T.; Xue, L.; Zeng, L.-W.; Liu, X.-G.; Zhang, Y.-H.; Jayne, J. T.; Ng, N. L.; Worsnop, D. R.

2010-09-01

As part of Campaigns of Air Quality Research in Beijing and Surrounding Region-2008 (CAREBeijing-2008), an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed in urban Beijing to characterize submicron aerosol particles during the time of 2008 Beijing Olympic Games and Paralympic Games (24 July to 20 September 2008). The campaign mean PM1 mass concentration was 63.1 ± 39.8 μg m-3; the mean composition consisted of organics (37.9%), sulfate (26.7%), ammonium (15.9%), nitrate (15.8%), black carbon (3.1%), and chloride (0.87%). The average size distributions of the species (except BC) were all dominated by an accumulation mode peaking at about 600 nm in vacuum aerodynamic diameter, and organics was characterized by an additional smaller mode extending below 100 nm. Positive Matrix Factorization (PMF) analysis of the high resolution organic mass spectral dataset differentiated the organic aerosol into four components, i.e., hydrocarbon-like (HOA), cooking-related (COA), and two oxygenated organic aerosols (OOA-1 and OOA-2), which on average accounted for 18.1, 24.4, 33.7 and 23.7% of the total organic mass, respectively. The HOA was identified to be closely associated with primary combustion sources, while the COA mass spectrum and diurnal pattern showed similar characteristics to that measured for cooking emissions. The OOA components correspond to aged secondary organic aerosol. Although the two OOA components have similar elemental (O/C, H/C) compositions, they display differences in mass spectra and time series which appear to correlate with the different source regions sampled during the campaign. Back trajectory clustering analysis indicated that the southerly air flows were associated with the highest PM1 pollution during the campaign. Aerosol particles in southern airmasses were especially rich in inorganic and oxidized organic species. Aerosol particles in northern airmasses contained a large fraction of primary HOA

Characteristics and direct radiative effect of mid-latitude continental aerosols: the ARM case

Directory of Open Access Journals (Sweden)

M. G. Iziomon

2003-01-01

Full Text Available A multi-year field measurement analysis of the characteristics and direct radiative effect of aerosols at the Southern Great Plains (SGP central facility of the Atmospheric Radiation Measurement (ARM Program is presented. Inter-annual mean and standard deviation of submicrometer scattering fraction (at 550 nm and Ångström exponent å (450 nm, 700 nm at the mid-latitude continental site are indicative of the scattering dominance of fine mode aerosol particles, being 0.84±0.03 and 2.25±0.09, respectively. We attribute the diurnal variation of submicron aerosol concentration to coagulation, photochemistry and the evolution of the boundary layer. Precipitation does not seem to play a role in the observed afternoon maximum in aerosol concentration. Submicron aerosol mass at the site peaks in the summer (12.1±6.7mg m-3, with the summer value being twice that in the winter. Of the chemically analyzed ionic components (which exclude carbonaceous aerosols, SO4= and NH4+ constitute the dominant species at the SGP seasonally, contributing 23-30% and 9-12% of the submicron aerosol mass, respectively. Although a minor species, there is a notable rise in NO3- mass fraction in winter. We contrast the optical properties of dust and smoke haze. The single scattering albedo w0 shows the most remarkable distinction between the two aerosol constituents. We also present aircraft measurements of vertical profiles of aerosol optical properties at the site. Annually, the lowest 1.2 km contributes 70% to the column total light scattering coefficient. Column-averaged and surface annual mean values of hemispheric backscatter fraction (at 550 nm, w0 (at 550 nm and å (450 nm, 700 nm agree to within 5% in 2001. Aerosols produce a net cooling (most pronounced in the spring at the ARM site

Generation and characterization of cyclosporine aerosols for administration by inhalation

International Nuclear Information System (INIS)

Hoover, M.D.; Muggenburg, B.A.; Snipes, M.B.; Wolff, R.K.; Yeh, H.C.; Griffith, B.P.; Burckart, G.J.; Mauderly, J.L.

1988-01-01

A method was developed for generating aerosols of the immunosuppressive agent cyclosporine and a gamma-emitting radiolabel ( 99m Tc) for administration by inhalation. Cyclosporine was dissolved in ethyl alcohol (EtOH) and nebulized with a Love- lace nebulizer operated with 50 psi compressed air. For a cyclosporine concentration of 25 mg/mL, the particle size of the aerosol was 0.7 μm activity median aerodynamic diameter (AMAD), with 1.8 geometric standard deviation (GSD). The clear solution of EtOH and cyclosporine became a cloudy suspension when a limited amount of saline solution containing a 99m Tc radiolabel was added. This occurred because cyclosporine is hydrophobic. If saline concentrations as high as 6% in EtOH by volume were used, a gummy residue formed in the nebulizer and the particle aerodynamic diameter became unacceptably large (4.7 μm). When the saline concentration was only 3 % (the minimum radiolabel volume needed for gamma camera studies of lung deposition), the suspensions of cyclosporine could be nebulized to give a particle size of 2.2 μm AMAD with 2.1 GSD. The radiolabel was uniformly distributed with the spherical cyclosporine particles. Concentrations and particle size distributions remained constant over 1-h generation periods. These aerosols have been used in inhalation studies with Beagle dogs. (author)

Aerosol chemical composition at Cabauw, the Netherlands as observed in two intensive periods in May 2008 and March 2009

NARCIS (Netherlands)

Mensah, A.A.; Holzinger, R.; Otjes, R.; Trimborn, A.; Mentel, T.F.; Brink, H. ten; Henzing, B.; Kiendler-Scharr, A.

2012-01-01

Observations of aerosol chemical composition in Cabauw, the Netherlands, are presented for two intensive measurement periods in May 2008 and March 2009. Sub-micron aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS) and is compared to observations from aerosol

The effect of changes in humidity on the size of submicron aerosols

International Nuclear Information System (INIS)

Phillips, C.R.; Khan, A.

1987-06-01

The effect of humidity on inhaled aerosols in the respiratory tract is to cause an increase in particle size of up to several times if the aerosol particle is hygroscopic. The presence of ionizing radiation and air ions (for example, from uranium and radon/thoron) increases the tendency of water vapour to nucleate. The desposition of particles in the lung is enhanced by high charge density (>10 charges/particle). Radon has been reported to play an important role in the formation of sulphate and nitrate particles in the atmosphere. A detailed overview of the effect of humidity on aerosols is presented in the present work. Results of experimental measurements made on NaCl (hygroscopic) and kerosene combustion (hydrophobic) aerosols under ambient and humid conditions are reported. Initial aerosol conditions were 20 degrees C and 35% R.H. Final aerosol conditions were maintained at 37 degrees C and 100% R.H. in order to simulate the conditions inside the respiratory tract. An average growth factor of 1.9 ± 0.4 (standard deviation) was observed for the NaCl aerosol and 1.3 ± 0.2 (standard deviation) for the kerosene aerosol. For the activity size distribution, however, the NaCl aerosols were observed to grow by an average factor of only 1.2 ± 0.1 (standard deviation) whereas the kerosene aerosols grew by a factor of 1.3 ± 0.2 (standard deviation)

Long-term real-time chemical characterization of submicron aerosols at Montsec (southern Pyrenees, 1570 m a.s.l.)

Science.gov (United States)

Ripoll, A.; Minguillón, M. C.; Pey, J.; Jimenez, J. L.; Day, D. A.; Sosedova, Y.; Canonaco, F.; Prévôt, A. S. H.; Querol, X.; Alastuey, A.

2015-03-01

Real-time measurements of inorganic (sulfate, nitrate, ammonium, chloride and black carbon (BC)) and organic submicron aerosols (particles with an aerodynamic diameter of less than 1 μm) from a continental background site (Montsec, MSC, 1570 m a.s.l.) in the western Mediterranean Basin (WMB) were conducted for 10 months (July 2011-April 2012). An aerosol chemical speciation monitor (ACSM) was co-located with other online and offline PM1 measurements. Analyses of the hourly, diurnal, and seasonal variations are presented here, for the first time, for this region. Seasonal trends in PM1 components are attributed to variations in evolution of the planetary boundary layer (PBL) height, air mass origin, and meteorological conditions. In summer, the higher temperature and solar radiation increases convection, enhancing the growth of the PBL and the transport of anthropogenic pollutants towards high altitude sites. Furthermore, the regional recirculation of air masses over the WMB creates a continuous increase in the background concentrations of PM1 components and causes the formation of reservoir layers at relatively high altitudes. The combination of all these atmospheric processes results in a high variability of PM1 components, with poorly defined daily patterns, except for the organic aerosols (OA). OA was mostly composed (up to 90%) of oxygenated organic aerosol (OOA), split in two types: semivolatile (SV-OOA) and low-volatility (LV-OOA), the rest being hydrocarbon-like OA (HOA). The marked diurnal cycles of OA components regardless of the air mass origin indicates that they are not only associated with anthropogenic and long-range-transported secondary OA (SOA) but also with recently produced biogenic SOA. Very different conditions drive the aerosol phenomenology in winter at MSC. The thermal inversions and the lower vertical development of the PBL leave MSC in the free troposphere most of the day, being affected by PBL air masses only after midday, when the

Chemical composition, sources, and aging process of submicron aerosols in Beijing: Contrast between summer and winter

Science.gov (United States)

Hu, Weiwei; Hu, Min; Hu, Wei; Jimenez, Jose L.; Yuan, Bin; Chen, Wentai; Wang, Ming; Wu, Yusheng; Chen, Chen; Wang, Zhibin; Peng, Jianfei; Zeng, Limin; Shao, Min

2016-02-01

To investigate the seasonal characteristics of submicron aerosol (PM1) in Beijing urban areas, a high-resolution time-of-flight aerosol-mass-spectrometer (HR-ToF-AMS) was utilized at an urban site in summer (August to September 2011) and winter (November to December 2010), coupled with multiple state of the art online instruments. The average mass concentrations of PM1 (60-84 µg m-3) and its chemical compositions in different campaigns of Beijing were relatively consistent in recent years. In summer, the daily variations of PM1 mass concentrations were stable and repeatable. Eighty-two percent of the PM1 mass concentration on average was composed of secondary species, where 62% is secondary inorganic aerosol and 20% secondary organic aerosol (SOA). In winter, PM1 mass concentrations changed dramatically because of the different meteorological conditions. The high average fraction (58%) of primary species in PM1 including primary organic aerosol (POA), black carbon, and chloride indicates primary emissions usually played a more important role in the winter. However, aqueous chemistry resulting in efficient secondary formation during occasional periods with high relative humidity may also contribute substantially to haze in winter. Results of past OA source apportionment studies in Beijing show 45-67% of OA in summer and 22-50% of OA in winter can be composed of SOA. Based on the source apportionment results, we found 45% POA in winter and 61% POA in summer are from nonfossil sources, contributed by cooking OA in both seasons and biomass burning OA (BBOA) in winter. Cooking OA, accounting for 13-24% of OA, is an important nonfossil carbon source in all years of Beijing and should not be neglected. The fossil sources of POA include hydrocarbon-like OA from vehicle emissions in both seasons and coal combustion OA (CCOA) in winter. The CCOA and BBOA were the two main contributors (57% of OA) for the highest OA concentrations (>100 µg m-3) in winter. The POA

Aerosol volatility in a boreal forest environment

Science.gov (United States)

Häkkinen, S. A. K.; ńijälä, M.; Lehtipalo, K.; Junninen, H.; Virkkula, A.; Worsnop, D. R.; Kulmala, M.; Petäjä, T.; Riipinen, I.

2012-04-01

Climate and health effects of atmospheric aerosols are determined by their properties such as their chemical composition. Aerosol chemical composition can be studied indirectly by measuring volatility of aerosol particles. The volatility of submicron aerosol particles (20-500 nm) was studied in a boreal forest site at SMEAR II (Station for Measuring Ecosystem-Atmosphere Relations II) station (Vesala et al., 1998) in Hyytiälä, Finland, during 01/2008-05/2010. The instrument used for the measurements was VDMPS (Volatility Differential Mobility Particle Sizer), which consists of two separate instruments: DMPS (Differential Mobility Particle Sizer, Aalto et al., 2001) and TD (Thermodenuder, Wehner et al., 2002). Aerosol evaporation was examined by heating the aerosol and comparing the total aerosol mass before and after heating. In the VDMPS system ambient aerosol sample was heated up to temperatures ranging from 80 °C to 280 °C. The higher the heating temperature was the more aerosol material was evaporated. There was a non-volatile residual present in aerosol particles when heated up to 280 °C. This residual explained (20±8)% of the total aerosol mass. Aerosol non-volatile mass fraction was highest during winter and smallest during summer months. The role of black carbon in the observed non-volatile residual was determined. Black carbon explained 40 to 90% of the non-volatile mass. Especially during colder seasons noticeable amount of non-volatile material, something else than black carbon, was observed. According to Kalberer et al. (2004) some atmospheric organic species can form polymers that have high evaporation temperatures. Also low-volatile organic salts may contribute to the non-volatile aerosol (Smith et al., 2010). Aerosol mass composition measured directly with AMS (Aerosol Mass Spectrometer, Jayne et al., 2000) was analyzed in order to examine the properties of the non-volatile material (other than black carbon). The AMS measurements were performed

Real-Time Measurement of Electronic Cigarette Aerosol Size Distribution and Metals Content Analysis.

Science.gov (United States)

Mikheev, Vladimir B; Brinkman, Marielle C; Granville, Courtney A; Gordon, Sydney M; Clark, Pamela I

2016-09-01

Electronic cigarette (e-cigarette) use is increasing worldwide and is highest among both daily and nondaily smokers. E-cigarettes are perceived as a healthier alternative to combustible tobacco products, but their health risk factors have not yet been established, and one of them is lack of data on aerosol size generated by e-cigarettes. We applied a real-time, high-resolution aerosol differential mobility spectrometer to monitor the evolution of aerosol size and concentration during puff development. Particles generated by e-cigarettes were immediately delivered for analysis with minimal dilution and therefore with minimal sample distortion, which is critically important given the highly dynamic aerosol/vapor mixture inherent to e-cigarette emissions. E-cigarette aerosols normally exhibit a bimodal particle size distribution: nanoparticles (11-25nm count median diameter) and submicron particles (96-175nm count median diameter). Each mode has comparable number concentrations (10(7)-10(8) particles/cm(3)). "Dry puff" tests conducted with no e-cigarette liquid (e-liquid) present in the e-cigarette tank demonstrated that under these conditions only nanoparticles were generated. Analysis of the bulk aerosol collected on the filter showed that e-cigarette emissions contained a variety of metals. E-cigarette aerosol size distribution is different from that of combustible tobacco smoke. E-cigarettes generate high concentrations of nanoparticles and their chemical content requires further investigation. Despite the small mass of nanoparticles, their toxicological impact could be significant. Toxic chemicals that are attached to the small nanoparticles may have greater adverse health effects than when attached to larger submicron particles. The e-cigarette aerosol size distribution is different from that of combustible tobacco smoke and typically exhibits a bimodal behavior with comparable number concentrations of nanoparticles and submicron particles. While vaping the e

Enhancing non-refractory aerosol apportionment from an urban industrial site through receptor modeling of complete high time-resolution aerosol mass spectra

Science.gov (United States)

McGuire, M. L.; Chang, R. Y.-W.; Slowik, J. G.; Jeong, C.-H.; Healy, R. M.; Lu, G.; Mihele, C.; Abbatt, J. P. D.; Brook, J. R.; Evans, G. J.

2014-08-01

Receptor modeling was performed on quadrupole unit mass resolution aerosol mass spectrometer (Q-AMS) sub-micron particulate matter (PM) chemical speciation measurements from Windsor, Ontario, an industrial city situated across the Detroit River from Detroit, Michigan. Aerosol and trace gas measurements were collected on board Environment Canada's Canadian Regional and Urban Investigation System for Environmental Research (CRUISER) mobile laboratory. Positive matrix factorization (PMF) was performed on the AMS full particle-phase mass spectrum (PMFFull MS) encompassing both organic and inorganic components. This approach compared to the more common method of analyzing only the organic mass spectra (PMFOrg MS). PMF of the full mass spectrum revealed that variability in the non-refractory sub-micron aerosol concentration and composition was best explained by six factors: an amine-containing factor (Amine); an ammonium sulfate- and oxygenated organic aerosol-containing factor (Sulfate-OA); an ammonium nitrate- and oxygenated organic aerosol-containing factor (Nitrate-OA); an ammonium chloride-containing factor (Chloride); a hydrocarbon-like organic aerosol (HOA) factor; and a moderately oxygenated organic aerosol factor (OOA). PMF of the organic mass spectrum revealed three factors of similar composition to some of those revealed through PMFFull MS: Amine, HOA and OOA. Including both the inorganic and organic mass proved to be a beneficial approach to analyzing the unit mass resolution AMS data for several reasons. First, it provided a method for potentially calculating more accurate sub-micron PM mass concentrations, particularly when unusual factors are present, in this case the Amine factor. As this method does not rely on a priori knowledge of chemical species, it circumvents the need for any adjustments to the traditional AMS species fragmentation patterns to account for atypical species, and can thus lead to more complete factor profiles. It is expected that this

Enhancing non-refractory aerosol apportionment from an urban industrial site through receptor modelling of complete high time-resolution aerosol mass spectra

Science.gov (United States)

McGuire, M. L.; Chang, R. Y.-W.; Slowik, J. G.; Jeong, C.-H.; Healy, R. M.; Lu, G.; Mihele, C.; Abbatt, J. P. D.; Brook, J. R.; Evans, G. J.

2014-02-01

Receptor modelling was performed on quadrupole unit mass resolution aerosol mass spectrometer (Q-AMS) sub-micron particulate matter (PM) chemical speciation measurements from Windsor, Ontario, an industrial city situated across the Detroit River from Detroit, Michigan. Aerosol and trace gas measurements were collected on board Environment Canada's CRUISER mobile laboratory. Positive matrix factorization (PMF) was performed on the AMS full particle-phase mass spectrum (PMFFull MS) encompassing both organic and inorganic components. This approach was compared to the more common method of analysing only the organic mass spectra (PMFOrg MS). PMF of the full mass spectrum revealed that variability in the non-refractory sub-micron aerosol concentration and composition was best explained by six factors: an amine-containing factor (Amine); an ammonium sulphate and oxygenated organic aerosol containing factor (Sulphate-OA); an ammonium nitrate and oxygenated organic aerosol containing factor (Nitrate-OA); an ammonium chloride containing factor (Chloride); a hydrocarbon-like organic aerosol (HOA) factor; and a moderately oxygenated organic aerosol factor (OOA). PMF of the organic mass spectrum revealed three factors of similar composition to some of those revealed through PMFFull MS: Amine, HOA and OOA. Including both the inorganic and organic mass proved to be a beneficial approach to analysing the unit mass resolution AMS data for several reasons. First, it provided a method for potentially calculating more accurate sub-micron PM mass concentrations, particularly when unusual factors are present, in this case, an Amine factor. As this method does not rely on a priori knowledge of chemical species, it circumvents the need for any adjustments to the traditional AMS species fragmentation patterns to account for atypical species, and can thus lead to more complete factor profiles. It is expected that this method would be even more useful for HR-ToF-AMS data, due to the ability

Insights into characteristics, sources, and evolution of submicron aerosols during harvest seasons in the Yangtze River delta region, China

Science.gov (United States)

Zhang, Y. J.; Tang, L. L.; Wang, Z.; Yu, H. X.; Sun, Y. L.; Liu, D.; Qin, W.; Canonaco, F.; Prévôt, A. S. H.; Zhang, H. L.; Zhou, H. C.

2015-02-01

Atmospheric submicron particulate matter (PM1) is one of the most significant pollution components in China. Despite its current popularity in the studies of aerosol chemistry, the characteristics, sources and evolution of atmospheric PM1 species are still poorly understood in China, particularly for the two harvest seasons, namely, the summer wheat harvest and autumn rice harvest. An Aerodyne Aerosol Chemical Speciation Monitor (ACSM) was deployed for online monitoring of PM1 components during summer and autumn harvest seasons in urban Nanjing, in the Yangtze River delta (YRD) region of China. PM1 components were shown to be dominated by organic aerosol (OA, 39 and 41%) and nitrate (23 and 20%) during the harvest seasons (the summer and autumn harvest). Positive matrix factorization (PMF) analysis of the ACSM OA mass spectra resolved four OA factors: hydrocarbon-like mixed with cooking-related OA (HOA + COA), fresh biomass-burning OA (BBOA), oxidized biomass-burning-influenced OA (OOA-BB), and highly oxidized OA (OOA); in particular the oxidized BBOA contributes ~80% of the total BBOA loadings. Both fresh and oxidized BBOA exhibited apparent diurnal cycles with peak concentration at night, when the high ambient relative humidity and low temperature facilitated the partitioning of semi-volatile organic species into the particle phase. The fresh BBOA concentrations for the harvests are estimated as BBOA = 15.1 × (m/z 60-0.26% × OA), where m/z (mass-to-charge ratio) 60 is a marker for levoglucosan-like species. The (BBOA + OOA-BB)/ΔCO, (ΔCO is the CO minus background CO), decreases as a function of f44 (fraction of m/z 44 in OA signal), which might indicate that BBOA was oxidized to less volatile OOA, e.g., more aged and low volatility OOA (LV-OOA) during the aging process. Analysis of air mass back trajectories indicates that the high BB pollutant concentrations are linked to the air masses from the western (summer harvest) and southern (autumn harvest) areas.

Aircraft-based Observations and Modeling of Wintertime Submicron Aerosol Composition over the Northeastern U.S.

Science.gov (United States)

Shah, V.; Jaegle, L.; Schroder, J. C.; Campuzano-Jost, P.; Jimenez, J. L.; Guo, H.; Sullivan, A.; Weber, R. J.; Green, J. R.; Fiddler, M.; Bililign, S.; Lopez-Hilfiker, F.; Lee, B. H.; Thornton, J. A.

2017-12-01

Submicron aerosol particles (PM1) remain a major air pollution concern in the urban areas of northeastern U.S. While SO2 and NOx emission controls have been effective at reducing summertime PM1 concentrations, this has not been the case for wintertime sulfate and nitrate concentrations, suggesting a nonlinear response during winter. During winter, organic aerosol (OA) is also an important contributor to PM1 mass despite low biogenic emissions, suggesting the presence of important urban sources. We use aircraft-based observations collected during the Wintertime INvestigation of Transport, Emissions and Reactivity (WINTER) campaign (Feb-March 2015), together with the GEOS-Chem chemical transport model, to investigate the sources and chemical processes governing wintertime PM1 over the northeastern U.S. The mean observed concentration of PM1 between the surface and 1 km was 4 μg m-3, about 30% of which was composed of sulfate, 20% nitrate, 10% ammonium, and 40% OA. The model reproduces the observed sulfate, nitrate and ammonium concentrations after updates to HNO3 production and loss, SO2 oxidation, and NH3 emissions. We find that 65% of the sulfate formation occurs in the aqueous phase, and 55% of nitrate formation through N2O5 hydrolysis, highlighting the importance of multiphase and heterogeneous processes during winter. Aqueous-phase sulfate production and the gas-particle partitioning of nitrate and ammonium are affected by atmospheric acidity, which in turn depends on the concentration of these species. We examine these couplings with GEOS-Chem, and assess the response of wintertime PM1 concentrations to further emission reductions based on the U.S. EPA projections for the year 2023. For OA, we find that the standard GEOS-Chem simulation underestimates the observed concentrations, but a simple parameterization developed from previous summer field campaigns is able to reproduce the observations and the contribution of primary and secondary OA. We find that

Soft ionization of thermally evaporated hypergolic ionic liquid aerosols

Energy Technology Data Exchange (ETDEWEB)

University of California; ERC, Incorporated, Edwards Air Force Base; Air Force Research Laboratory, Edwards Air Force Base; National Synchrotron Radiation Research Center (NSRRC); Institute of Chemistry, Hebrew University; Koh, Christine J.; Liu, Chen-Lin; Harmon, Christopher W.; Strasser, Daniel; Golan, Amir; Kostko, Oleg; Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; Leone, Stephen R.

2011-07-19

Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N?]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca?]), are generated by vaporizing ionic liquid submicron aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N?]ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~;;0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid submicron aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally ?cooler? source of isolated intact ion pairs in the gas phase compared to effusive sources.

Two years of near real-time chemical composition of submicron aerosols in the region of Paris using an Aerosol Chemical Speciation Monitor (ACSM) and a multi-wavelength Aethalometer

Science.gov (United States)

Petit, J.-E.; Favez, O.; Sciare, J.; Crenn, V.; Sarda-Estève, R.; Bonnaire, N.; Močnik, G.; Dupont, J.-C.; Haeffelin, M.; Leoz-Garziandia, E.

2015-03-01

Aerosol mass spectrometer (AMS) measurements have been successfully used towards a better understanding of non-refractory submicron (PM1) aerosol chemical properties based on short-term campaigns. The recently developed Aerosol Chemical Speciation Monitor (ACSM) has been designed to deliver quite similar artifact-free chemical information but for low cost, and to perform robust monitoring over long-term periods. When deployed in parallel with real-time black carbon (BC) measurements, the combined data set allows for a quasi-comprehensive description of the whole PM1 fraction in near real time. Here we present 2-year long ACSM and BC data sets, between mid-2011 and mid-2013, obtained at the French atmospheric SIRTA supersite that is representative of background PM levels of the region of Paris. This large data set shows intense and time-limited (a few hours) pollution events observed during wintertime in the region of Paris, pointing to local carbonaceous emissions (mainly combustion sources). A non-parametric wind regression analysis was performed on this 2-year data set for the major PM1 constituents (organic matter, nitrate, sulfate and source apportioned BC) and ammonia in order to better refine their geographical origins and assess local/regional/advected contributions whose information is mandatory for efficient mitigation strategies. While ammonium sulfate typically shows a clear advected pattern, ammonium nitrate partially displays a similar feature, but, less expectedly, it also exhibits a significant contribution of regional and local emissions. The contribution of regional background organic aerosols (OA) is significant in spring and summer, while a more pronounced local origin is evidenced during wintertime, whose pattern is also observed for BC originating from domestic wood burning. Using time-resolved ACSM and BC information, seasonally differentiated weekly diurnal profiles of these constituents were investigated and helped to identify the main

Preliminary characterization of submicron secondary aerosol in the amazon forest - ATTO station

Science.gov (United States)

Carbone, S.; Ferreira De Brito, J.; Andreae, M. O.; Pöhlker, C.; Chi, X.; Saturno, J.; Barbosa, H. M.; Artaxo, P.

2014-12-01

Biogenic secondary organic aerosol particles are investigated in the Amazon in the context of the GoAmazon Project. The forest naturally emits a large number of gaseous compounds; they are called the volatile organic compounds (VOCs). They are emitted through processes that are not totally understood. Part of those gaseous compounds are converted into aerosol particles, which affect the biogeochemical cycles, the radiation balance, the mechanisms involving cloud formation and evolution, among few other important effects. In this study the aerosol life-cycle is investigated at the ATTO station, which is located about 150 km northeast of Manaus, with emphasis on the natural organic component and its impacts in the ecosystem. To achieve these objectives physical and chemical aerosol properties have been investigated, such as the chemical composition with aerosol chemical speciation monitor (ACSM), nanoparticle size distribution (using the SMPS - Scanning Mobility Particle Sizer), optical properties with measurements of scattering and absorption (using nephelometers and aethalometers). Those instruments have been operating continuously since February 2014 together with trace gases (O3, CO2, CO, SO2 and NOx) analyzers and additional meteorological instruments. On average PM1 (the sum of black carbon, organic and inorganic ions) totalized 1.0±0.3 μg m-3, where the organic fraction was dominant (75%). During the beginning of the dry season (July/August) the organic aerosol presented a moderate oxygenated character with the oxygen to carbon ratio (O:C) of 0.7. In the wet season some episodes containing significant amount of chloride and backward wind trajectories suggest aerosol contribution from the Atlantic Ocean. A more comprehensive analysis will include an investigation of the different oxidized fractions of the organic aerosol and optical properties.

Radiolabeled antibodies in cancer. Oncology Overview

International Nuclear Information System (INIS)

1984-11-01

Oncology Overviews are a service of the International Cancer Research Data Bank (ICRDB) Program of the National Cancer Institute, intended to facilitate and promote the exchange of information between cancer scientists by keeping them aware of literature related to their research being published by other laboratories through the world. Each Oncology Overview represents a survey of the literature associated with a selected area of cancer research. It contains abstracts of articles which have been selected and organized by researchers associated with the field. Contents: Radiolabeled antibodies--labeling and imaging techniques; Radiolabeled antibodies--carcinoembryonic antigen; Radiolabeled antibodies--alpha-fetoprotein; Radiolabeled antibodies--human chorionic gonadotropin; Radiolabeled antibodies--ferritin; Radiolabeled antibodies--imaging of colorectal tumors; Radiolabeled antibodies--imaging of malignant melanoma; Radiolabeled antibodies--imaging of urogenital tumors; Radiolabeled antibodies--imaging of thyroid tumors; Radiolabeled antibodies--other clinical studies; Radiolabeled antibodies--selected preclinical studies; Radiolabeled antibodies--reviews

Chemical characterization and source apportionment of submicron aerosols measured in Senegal during the 2015 SHADOW campaign

Science.gov (United States)

Rivellini, Laura-Hélèna; Chiapello, Isabelle; Tison, Emmanuel; Fourmentin, Marc; Féron, Anaïs; Diallo, Aboubacry; N'Diaye, Thierno; Goloub, Philippe; Canonaco, Francesco; Prévôt, André Stephan Henry; Riffault, Véronique

2017-09-01

The present study offers the first chemical characterization of the submicron (PM1) fraction in western Africa at a high time resolution, thanks to collocated measurements of nonrefractory (NR) species with an Aerosol Chemical Speciation Monitor (ACSM), black carbon and iron concentrations derived from absorption coefficient measurements with a 7-wavelength Aethalometer, and total PM1 determined by a TEOM-FDMS (tapered element oscillating microbalance-filtered dynamic measurement system) for mass closure. The field campaign was carried out over 3 months (March to June 2015) as part of the SHADOW (SaHAran Dust Over West Africa) project at a coastal site located in the outskirts of the city of Mbour, Senegal. With an averaged mass concentration of 5.4 µg m-3, levels of NR PM1 in Mbour were 3 to 10 times lower than those generally measured in urban and suburban polluted environments. Nonetheless the first half of the observation period was marked by intense but short pollution events (NR PM1 concentrations higher than 15 µg m-3), sea breeze phenomena and Saharan desert dust outbreaks (PM10 up to 900 µg m-3). During the second half of the campaign, the sampling site was mainly under the influence of marine air masses. The air masses on days under continental and sea breeze influences were dominated by organics (36-40 %), whereas sulfate particles were predominant (40 %) for days under oceanic influence. Overall, measurements showed that about three-quarters of the total PM1 were explained by NR PM1, BC (black carbon) and Fe (a proxy for dust) concentrations, leaving approximately one-quarter for other refractory species. A mean value of 4.6 % for the Fe / PM1 ratio was obtained. Source apportionment of the organic fraction, using positive matrix factorization (PMF), highlighted the impact of local combustion sources, such as traffic and residential activities, which contribute on average to 52 % of the total organic fraction. A new organic aerosol (OA) source

SECONDARY ORGANIC AEROSOL FORMATION FROM THE OXIDATION OF AROMATIC HYDROCARBONS IN THE PRESENCE OF DRY SUBMICRON AMMONIUM SULFATE AEROSOL

Science.gov (United States)

A laboratory study was conducted to examine formation of secondary organic aerosols. A smog chamber system was developed for studying gas-aerosol interactions in a dynamic flow reactor. These experiments were conducted to investigate the fate of gas and aerosol phase compounds ...

Nasal deposition of ciclesonide nasal aerosol and mometasone aqueous nasal spray in allergic rhinitis patients.

Science.gov (United States)

Emanuel, Ivor A; Blaiss, Michael S; Meltzer, Eli O; Evans, Philip; Connor, Alyson

2014-01-01

Sensory attributes of intranasal corticosteroids, such as rundown to the back of the throat, may influence patient treatment preferences. This study compares the nasal deposition and nasal retention of a radiolabeled solution of ciclesonide nasal aerosol (CIC-hydrofluoroalkane [HFA]) with a radiolabeled suspension of mometasone furoate monohydrate aqueous nasal spray (MFNS) in subjects with either perennial allergic rhinitis (AR) or seasonal AR. In this open-label, single-dose, randomized, crossover scintigraphy study, 14 subjects with symptomatic AR received a single dose of radiolabeled 74-μg CIC-HFA (37 μg/spray, 1 spray/each nostril) via a nasal metered-dose inhaler or a single dose of radiolabeled 200-μg MFNS (50 μg/spray, 2 sprays/each nostril), with a minimum 5-day washout period between treatments. Initial deposition (2 minutes postdose) of radiolabeled CIC-HFA and MFNS in the nasal cavity, nasopharynx, and on nasal wipes, and retention of radioactivity in the nasal cavity and nasal run-out on nasal wipes at 2, 4, 6, 8, and 10 minutes postdose were quantified with scintigraphy. At 2 and 10 minutes postdose, deposition of radiolabeled CIC-HFA was significantly higher in the nasal cavity versus radiolabeled MFNS (99.42% versus 86.50% at 2 minutes, p = 0.0046; and 81.10% versus 54.31% at 10 minutes, p Deposition of radioactivity on nasal wipes was significantly higher with MFNS versus CIC-HFA at all five time points, and posterior losses of radiolabeled formulation were significantly higher with MFNS at 6, 8, and 10 minutes postdose. In this scintigraphic study, significantly higher nasal deposition and retention of radiolabeled aerosol CIC-HFA were observed versus radiolabeled aqueous MFNS in subjects with AR.

Seasonal variations in high time-resolved chemical compositions, sources, and evolution of atmospheric submicron aerosols in the megacity Beijing

Science.gov (United States)

Hu, Wei; Hu, Min; Hu, Wei-Wei; Zheng, Jing; Chen, Chen; Wu, Yusheng; Guo, Song

2017-08-01

A severe regional haze problem in the megacity Beijing and surrounding areas, caused by fast formation and growth of fine particles, has attracted much attention in recent years. In order to investigate the secondary formation and aging process of urban aerosols, four intensive campaigns were conducted in four seasons between March 2012 and March 2013 at an urban site in Beijing (116.31° E, 37.99° N). An Aerodyne high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS) was deployed to measure non-refractory chemical components of submicron particulate matter (NR-PM1). The average mass concentrations of PM1 (NR-PM1+black carbon) were 45.1 ± 45.8, 37.5 ± 31.0, 41.3 ± 42.7, and 81.7 ± 72.4 µg m-3 in spring, summer, autumn, and winter, respectively. Organic aerosol (OA) was the most abundant component in PM1, accounting for 31, 33, 44, and 36 % seasonally, and secondary inorganic aerosol (SNA, sum of sulfate, nitrate, and ammonium) accounted for 59, 57, 43, and 55 % of PM1 correspondingly. Based on the application of positive matrix factorization (PMF), the sources of OA were obtained, including the primary ones of hydrocarbon-like (HOA), cooking (COA), biomass burning OA (BBOA) and coal combustion OA (CCOA), and secondary component oxygenated OA (OOA). OOA, which can be split into more-oxidized (MO-OOA) and less-oxidized OOA (LO-OOA), accounted for 49, 69, 47, and 50 % in four seasons, respectively. Totally, the fraction of secondary components (OOA+SNA) contributed about 60-80 % to PM1, suggesting that secondary formation played an important role in the PM pollution in Beijing, and primary sources were also non-negligible. The evolution process of OA in different seasons was investigated with multiple metrics and tools. The average carbon oxidation states and other metrics show that the oxidation state of OA was the highest in summer, probably due to both strong photochemical and aqueous-phase oxidations. It was indicated by the good correlations

Fourteen months of on-line measurements of the non-refractory submicron aerosol at the Jungfraujoch (3580 m a.s.l.) - chemical composition, origins and organic aerosol sources

Science.gov (United States)

Fröhlich, R.; Cubison, M. J.; Slowik, J. G.; Bukowiecki, N.; Canonaco, F.; Croteau, P. L.; Gysel, M.; Henne, S.; Herrmann, E.; Jayne, J. T.; Steinbacher, M.; Worsnop, D. R.; Baltensperger, U.; Prévôt, A. S. H.

2015-10-01

Chemically resolved (organic, nitrate, sulfate, ammonium) data of non-refractory submicron (NR-PM1) aerosol from the first long-term deployment (27 July 2012 to 02 October 2013) of a time-of-flight aerosol chemical speciation monitor (ToF-ACSM) at the Swiss high-altitude site Jungfraujoch (JFJ; 3580 m a.s.l.) are presented. Besides total mass loadings, diurnal variations and relative species contributions during the different meteorological seasons, geographical origin and sources of organic aerosol (OA) are discussed. Backward transport simulations show that the highest (especially sulfate) concentrations of NR-PM1 were measured in air masses advected to the station from regions south of the JFJ, while lowest concentrations were seen from western regions. OA source apportionment for each season was performed using the Source Finder (SoFi) interface for the multilinear engine (ME-2). OA was dominated in all seasons by oxygenated OA (OOA, 71-88 %), with lesser contributions from local tourism-related activities (7-12 %) and hydrocarbon-like OA related to regional vertical transport (3-9 %). In summer the OOA can be separated into a background low-volatility OA (LV-OOA I, possibly associated with long-range transport) and a slightly less oxidised low-volatility OA (LV-OOA II) associated with regional vertical transport. Wood burning-related OA associated with regional transport was detected during the whole winter 2012/2013 and during rare events in summer 2013, in the latter case attributed to small-scale transport for the surrounding valleys. Additionally, the data were divided into periods with free tropospheric (FT) conditions and periods with planetary boundary layer (PBL) influence, enabling the assessment of the composition for each. Most nitrate and part of the OA are injected from the regional PBL, while sulfate is mainly produced in the FT. The south/north gradient of sulfate is also pronounced in FT air masses (sulfate mass fraction from the south: 45

Submicron superconducting structures

International Nuclear Information System (INIS)

Golovashkin, A.I.; Lykov, A.N.

1986-01-01

An overview of works concerning superconducting structures of submicron dimensions and a system of such structures is given. It is noted that usage of the above structures in superconducting microelectronics permits, first, to increase the element packing density, to decrease the signal transmission time, capacity, power dissipated in high-frequency applications. Secondly, negligible coherence length in transition metals, their alloys and high-temperature compounds also restrict the dimensions of superconducting weak couplings when the 'classical' Josephson effect is displayed. The most effective methods for production of submicron superconducting structures are the following: lithography, double scribering. Recently the systems of superconducting submicron elements are extensively studied. It is shown that such systems can be phased by magnetic field

Spatiotemporal Variation in Composition of Submicron Particles in Santiago Metropolitan Region, Chile

Directory of Open Access Journals (Sweden)

Matías Tagle

2018-05-01

Full Text Available The chemical composition of submicron particles (aerodynamic diameter Da < 1.0 μm was investigated at three locations in the Santiago Metropolitan Region (SMR, Chile. Measurements campaigns were conducted in winter and spring 2016, at representative sites of a rural, urban, and urban receptor environment. Instrumentation consisted of an optical analyzer to determine Black Carbon (BC and the Aerosol Chemical Speciation Monitor (ACSM to measure concentrations of particulate chloride (Cl−, nitrate (NO3-, sulfate (SO42-, ammonium (NH4+, and non-refractory carbonaceous species (organics. Complementary data, such as ozone concentration and meteorological parameters were obtained from the public air quality network. Results showed that in both the winter and spring seasons the organics predominated in the mass of submicron particles. This fraction was followed in decreasing order by NO3-, NH4+, BC, SO42-, and Cl−. The highest average organics concentrations were measured in winter at the urban (32.2 μg m−3 and urban receptor sites (20.1 μg m−3. In winter, average concentrations of both NO3- and NH4+ were higher at the urban receptor site (12.3 and 4.5 μg m−3, respectively when compared to the urban site (6.4 and 3.1 μg m−3, respectively. In general, all the measured species were present in higher concentrations during winter, excepting SO42-, which was the only one that increased during spring. The transition toward spring was also associated with an acidification of the aerosol at the rural and urban receptor site, while at the urban site the aerosol was observed alkaline. The highest average ozone concentration during both the winter and spring seasons were recorded at the urban receptor site (7.2 and 24.0 ppb, respectively. The study reports data showing that the atmosphere in the SMR has a considerable load of particulate organic compounds, NO3- and NH4+, which are in higher concentrations at urban sites during the winter season

Rural continental aerosol properties and processes observed during the Hohenpeissenberg Aerosol Characterization Experiment (HAZE2002

Directory of Open Access Journals (Sweden)

N. Hock

2008-02-01

Full Text Available Detailed investigations of the chemical and microphysical properties of rural continental aerosols were performed during the HAZE2002 experiment, which was conducted in May 2002 at the Meteorological Observatory Hohenpeissenberg (DWD in Southern Germany.

Online measurements included: Size-resolved chemical composition of submicron particles; total particle number concentrations and size distributions over the diameter range of 3 nm to 9 μm; gas-phase concentration of monoterpenes, CO, O₃, OH, and H₂SO₄. Filter sampling and offline analytical techniques were used to determine: Fine particle mass (PM2.5, organic, elemental and total carbon in PM2.5 (OC2.5, EC2.5, TC2.5, and selected organic compounds (dicarboxylic acids, polycyclic aromatic hydrocarbons, proteins.

Overall, the non-refractory components of submicron particles detected by aerosol mass spectrometry (PM1, 6.6±5.4 μg m⁻³, arithmetic mean and standard deviation accounted for ~62% of PM2.5 determined by filter gravimetry (10.6±4.7 μg m⁻³. The relative proportions of non-refractory submicron particle components were: (23±39% ammonium nitrate, (27±23% ammonium sulfate, and (50±40% organics (OM1. OM1 was closely correlated with PM1 (r²=0.9 indicating a near-constant ratio of non-refractory organics and inorganics.

The average ratio of OM1 to OC2.5 was 2.1±1.4, indicating a high proportion of heteroelements in the organic fraction of the sampled rural aerosol. This is consistent with the high ratio of oxygenated organic aerosol (OOA over hydrocarbon-like organic aerosol (HOA inferred from the AMS results (4:1, and also with the high abundance of proteins (~3% indicating a high proportion of primary biological material (~30% in PM2.5. This finding was confirmed by low abundance of PAHs (<1 ng m⁻³ and EC (<1 μg m⁻³ in PM2.5 and detection of several

Secondary aerosols from power plant effluents: delivery and in vivo detection systems

International Nuclear Information System (INIS)

Parks, N.J.; Raabe, O.G.; Bradley, E.; Raub, J.

1976-01-01

An experimental system is described for the generation of radiolabeled monodisperse aerosols, which are physico-chemically analogous to aerosols produced as secondary products of gaseous fossil fuel power plant emissions of SO 2 and NO 2 . The experimental system for inhalation exposure of non-human primates to these particles and the in vivo determination of systemic distribution and target organs is discussed

Seasonal variations in high time-resolved chemical compositions, sources, and evolution of atmospheric submicron aerosols in the megacity Beijing

Directory of Open Access Journals (Sweden)

W. Hu

2017-08-01

Full Text Available A severe regional haze problem in the megacity Beijing and surrounding areas, caused by fast formation and growth of fine particles, has attracted much attention in recent years. In order to investigate the secondary formation and aging process of urban aerosols, four intensive campaigns were conducted in four seasons between March 2012 and March 2013 at an urban site in Beijing (116.31° E, 37.99° N. An Aerodyne high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS was deployed to measure non-refractory chemical components of submicron particulate matter (NR-PM1. The average mass concentrations of PM1 (NR-PM1+black carbon were 45.1 ± 45.8, 37.5 ± 31.0, 41.3 ± 42.7, and 81.7 ± 72.4 µg m−3 in spring, summer, autumn, and winter, respectively. Organic aerosol (OA was the most abundant component in PM1, accounting for 31, 33, 44, and 36 % seasonally, and secondary inorganic aerosol (SNA, sum of sulfate, nitrate, and ammonium accounted for 59, 57, 43, and 55 % of PM1 correspondingly. Based on the application of positive matrix factorization (PMF, the sources of OA were obtained, including the primary ones of hydrocarbon-like (HOA, cooking (COA, biomass burning OA (BBOA and coal combustion OA (CCOA, and secondary component oxygenated OA (OOA. OOA, which can be split into more-oxidized (MO-OOA and less-oxidized OOA (LO-OOA, accounted for 49, 69, 47, and 50 % in four seasons, respectively. Totally, the fraction of secondary components (OOA+SNA contributed about 60–80 % to PM1, suggesting that secondary formation played an important role in the PM pollution in Beijing, and primary sources were also non-negligible. The evolution process of OA in different seasons was investigated with multiple metrics and tools. The average carbon oxidation states and other metrics show that the oxidation state of OA was the highest in summer, probably due to both strong photochemical and aqueous-phase oxidations

Natural and Anthropogenic Influences on Atmospheric Aerosol Variability

Energy Technology Data Exchange (ETDEWEB)

Asmi, A.

2012-07-01

Aerosol particles are everywhere in the atmosphere. They are a key factor in many important processes in the atmosphere, including cloud formation, scattering of incoming solar radiation and air chemistry. The aerosol particles have relatively short lifetimes in lower atmosphere, typically from days to weeks, and thus they have a high spatial and temporal variability. This thesis concentrates on the extent and reasons of sub-micron aerosol particle variability in the lower atmosphere, using both global atmospheric models and analysis of observational data. Aerosol number size distributions in the lower atmosphere are affected strongly by the new particle formation. Perhaps more importantly, a strong influence new particle formation is also evident in the cloud condensation nuclei (CCN) concentrations, suggesting a major role of the sulphuric acid driven new particle formation in the climate system. In this thesis, the sub-micron aerosol number size distributions in the European regional background air were characterized for the first time from consistent, homogenized and comparable datasets. Some recent studies have suggested that differences in aerosol emissions between weekdays could also affect the weather via aerosol-cloud interactions. In this thesis, the weekday-to-weekday variation of CCN sized aerosol number concentrations in Europe were found to be much smaller than expected from earlier studies, based on particle mass measurements. This result suggests that a lack of week-day variability in meteorology is not necessarily a sign of weak aerosol-cloud interactions. An analysis of statistically significant trends in past decades of measured aerosol number concentrations from Europe, North America, Pacific islands and Antarctica generally show decreases in concentrations. The analysis of these changes show that a potential explanation for the decreasing trends is the general reduction of anthropogenic emissions, especially SO{sub 2}, although a combination of

On the contribution of organics to the North East Atlantic aerosol number concentration

International Nuclear Information System (INIS)

Bialek, Jakub; Dall’Osto, Manuel; Monahan, Ciaran; O’Dowd, Colin; Beddows, David

2012-01-01

k-means statistical-cluster analysis of submicron aerosol size distributions is combined with coincident humidity tandem differential mobility analyser data, leading to five unique aerosol categories for hygroscopic growth factors (HGFs): low sea-salt background marine, high sea-salt background marine, coastal nucleation, open ocean nucleation and anthropogenically influenced scenarios. When considering only marine conditions, and generic aerosol species associated with this environment (e.g. non-sea-salt sulfate, sea-salt, partly soluble organic matter and water insoluble organic matter), the two-year annual average contribution to aerosol number concentration from the different generic species was made up as follows: 46% (30–54%) of partially modified ammonium sulfate particles; 23% (11–40%) of partially modified sea-salt; and the remaining 31% (25–35%) contribution attributed to two distinct organic species as evidenced by different, but low, HGFs. The analysis reveals that on annual timescales, ∼30% of the submicron marine aerosol number concentration is sourced from predominantly organic aerosol while 60% of the anthropogenic aerosol number is predominantly organic. Coastal nucleation events show the highest contribution of the lowest HGF mode (1.19), although this contribution is more likely to be influenced by inorganic iodine oxides. While organic mass internally mixed with inorganic salts will lower the activation potential of these mixed aerosol types, thereby potentially reducing the concentration of cloud condensation nuclei (CCN), pure organic water soluble particles are still likely to be activated into cloud droplets, thereby increasing the concentration of CCN. A combination of dynamics and aerosol concentrations will determine which effect will prevail under given conditions. (letter)

Diurnal cycling of urban aerosols under different weather regimes

Science.gov (United States)

Gregorič, Asta; Drinovec, Luka; Močnik, Griša; Remškar, Maja; Vaupotič, Janja; Stanič, Samo

2016-04-01

A one month measurement campaign was performed in summer 2014 in Ljubljana, the capital of Slovenia (population 280,000), aiming to study temporal and spatial distribution of urban aerosols and the mixing state of primary and secondary aerosols. Two background locations were chosen for this purpose, the first one in the city center (urban background - KIS) and the second one in the suburban background (Brezovica). Simultaneous measurements of black carbon (BC) and particle number size distribution of submicron aerosols (PM1) were conducted at both locations. In the summer season emission from traffic related sources is expected to be the main local contribution to BC concentration. Concentrations of aerosol species and gaseous pollutants within the planetary boundary layer are controlled by the balance between emission sources of primary aerosols and gases, production of secondary aerosols, chemical reactions of precursor gases under solar radiation and the rate of dilution by mixing within the planetary boundary layer (PBL) as well as with tropospheric air. Only local emission sources contribute to BC concentration during the stable PBL with low mixing layer height, whereas during the time of fully mixed PBL, regionally transported BC and other aerosols can contribute to the surface measurements. The study describes the diurnal behaviour of the submicron aerosol at the urban and suburban background location under different weather regimes. Particles in three size modes - nucleation (humidity, wind speed and direction), diurnal profile differs for sunny, cloudy and rainy days. Nucleation mode particles were found to be subjected to lower daily variation and only slightly influenced by weather, as opposed to Aitken and accumulation mode particles. The highest correlation between BC and particle number concentration is observed during stable atmospheric conditions in the night and morning hours and is attributed to different particle size modes, depending on the

OCEANFILMS-2: Representing coadsorption of saccharides in marine films and potential impacts on modeled marine aerosol chemistry

Energy Technology Data Exchange (ETDEWEB)

Burrows, Susannah M. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Gobrogge, Eric [Department of Chemistry and Biochemistry, Montana State University, Bozeman Montana USA; Fu, Li [Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland Washington USA; Link, Katie [Department of Chemistry and Biochemistry, Montana State University, Bozeman Montana USA; Elliott, Scott M. [Climate, Ocean, and Sea Ice Modelling Group, Los Alamos National Laboratory, Los Alamos New Mexico USA; Wang, Hongfei [Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland Washington USA; Walker, Rob [Department of Chemistry and Biochemistry, Montana State University, Bozeman Montana USA

2016-08-10

Here we show that the addition of chemical interactions of soluble polysaccharides with a surfactant monolayer improves agreement of modeled sea spray chemistry with observed marine aerosol chemistry. In particular, the fraction of hydroxyl functional groups in modeled sea spray organic matter is increased, improving agreement with FTIR observations of marine aerosol composition. The overall organic fraction of submicron sea spray also increases, allowing organic mass fractions in the range 0.5 – 0.7 for submicron sea spray particles over highly active phytoplankton blooms. We show results from Sum Frequency Generation (SFG) experiments that support the modeling approach, by demonstrating that soluble polysaccharides can strongly adsorb to a lipid monolayer via columbic interactions under appropriate conditions.

Submicron X-ray diffraction

International Nuclear Information System (INIS)

MacDowell, Alastair; Celestre, Richard; Tamura, Nobumichi; Spolenak, Ralph; Valek, Bryan; Brown, Walter; Bravman, John; Padmore, Howard; Batterman, Boris; Patel, Jamshed

2000-01-01

At the Advanced Light Source in Berkeley the authors have instrumented a beam line that is devoted exclusively to x-ray micro diffraction problems. By micro diffraction they mean those classes of problems in Physics and Materials Science that require x-ray beam sizes in the sub-micron range. The instrument is for instance, capable of probing a sub-micron size volume inside micron sized aluminum metal grains buried under a silicon dioxide insulating layer. The resulting Laue pattern is collected on a large area CCD detector and automatically indexed to yield the grain orientation and deviatoric (distortional) strain tensor of this sub-micron volume. A four-crystal monochromator is then inserted into the beam, which allows monochromatic light to illuminate the same part of the sample. Measurement of diffracted photon energy allows for the determination of d spacings. The combination of white and monochromatic beam measurements allow for the determination of the total strain/stress tensor (6 components) inside each sub-micron sized illuminated volume of the sample

Radiolabelled sucralfate compositions

International Nuclear Information System (INIS)

Vasquez, T.E.; Bridges, R.L.; Braunstein, P.; Jansholt, A.

1984-01-01

A novel radiopharmaceutical composition comprising an aqueous solution or suspension containing a radiolabelled sucralfate or sucralfate derivative or precursor is claimed. The composition is effective for in vivo scintigraphic imaging of the gastrointestinal muscosal areas in humans. The sucralfate is combined with a radiolabelled albumin or other protein or protein derivative under acidic conditions

Production and characterization of submicron hematite (α−Fe{sub 2}O{sub 3}) particles by ultrasonic spray pyrolysis method

Energy Technology Data Exchange (ETDEWEB)

Kırcı, Burak; Ebin, Burçak; Gürmen, Sebahattin [Department of Metallurgical and Materials Engineering, Istanbul Technical University Istanbul (Turkey)

2013-12-16

The ultrasonic spray pyrolysis (USP) method has been used to prepare submicron hematite (α−Fe{sub 2}O{sub 3}) particles using two different industrial pickling solutions of iron chloride (41 g/L FeCl{sub 2} and 54 g/L FeCl{sub 3}) Particles were obtained by thermal decomposition of generated aerosols from precursor solutions using 1.7 MHz ultrasonic atomizer. Reaction temperature was set up at 800 °C and aerosol droplets were carried into the heated zone by 0.7 L/min air flow rate. X-Ray Diffraction (XRD) studies were used to determine the crystal structure and crystallite size of the particles. Results indicate that patterns correspond to hematite phase with rhombohedral crystal structure (space group: R3c). The crystallite sizes of particles prepared from FeCl{sub 2} and FeCl{sub 3} solutions that were calculated from Scherrer equation are 59 and 33 nm, respectively. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) investigations give detailed information about particle size, morphology and composition. SEM micrographs show that hematite nanoparticles aggregate and formed spherical secondary particles in submicron range.

Aerosol Chemical Composition and its Effects on Cloud-Aerosol Interactions during the 2007 CHAPS Experiment

Science.gov (United States)

Lee, Y.; Alexander, L.; Newburn, M.; Jayne, J.; Hubbe, J.; Springston, S.; Senum, G.; Andrews, B.; Ogren, J.; Kleinman, L.; Daum, P.; Berg, L.; Berkowitz, C.

2007-12-01

Chemical composition of submicron aerosol particles was determined using an Aerodyne Time-of-Flight Aerosol Mass Spectrometer (AMS) outfitted on the DOE G-1 aircraft during the Cumulus Humilis Aerosol Processing Study (CHAPS) conducted in Oklahoma City area in June 2007. The primary objective of CHAPS was to investigate the effects of urban emissions on cloud aerosol interactions as a function of processing of the emissions. Aerosol composition was typically determined at three different altitudes: below, in, and above cloud, in both upwind and downwind regions of the urban area. Aerosols were sampled from an isokinetic inlet with an upper size cut-off of ~1.5 micrometer. During cloud passages, the AMS also sampled particles that were dried from cloud droplets collected using a counter-flow virtual impactor (CVI) sampler. The aerosol mass concentrations were typically below 10 microgram per cubic meter, and were dominated by organics and sulfate. Ammonium was often less than required for complete neutralization of sulfate. Aerosol nitrate levels were very low. We noted that nitrate levels were significantly enhanced in cloud droplets compared to aerosols, most likely resulting from dissolution of gaseous nitric acid. Organic to sulfate ratios appeared to be lower in cloud droplets than in aerosols, suggesting cloud condensation nuclei properties of aerosol particles might be affected by loading and nature of the organic components in aerosols. In-cloud formation of sulfate was considered unimportant because of the very low SO2 concentration in the region. A detailed examination of the sources of the aerosol organic components (based on hydrocarbons determined using a proton transfer reaction mass spectrometer) and their effects on cloud formation as a function of atmospheric processing (based on the degree of oxidation of the organic components) will be presented.

On the sources of submicron aerosol particles in savannah: implications for climate and air quality

Energy Technology Data Exchange (ETDEWEB)

Vakkari, V.

2013-11-01

Aerosol is defined as solid or liquid particles suspended in a gas lighter than the particles, which means that the atmosphere we live in is an aerosol in itself. Although aerosol particles are only a trace component of the atmosphere they affect our lives in several ways. The aerosol particles can cause adverse health effects and deteriorate visibility, but they affect also the Earth s climate directly by scattering and absorbing solar radiation and indirectly by modulating the properties of the clouds. Anthropogenic aerosol particles have a net cooling effect on the climate, but the uncertainty in the amount of cooling is presently as large as the heating effect of carbon dioxide. To reduce the uncertainty in the aerosol climate effects, spatially representative reference data of high quality are needed for the global climate models. To be able to capture the diurnal and seasonal variability the data have to be collected continuously over time periods that cover at least one full seasonal cycle. Until recently such data have been nearly non-existing for continental Africa and hence one aim of this work was to establish a permanent measurement station measuring the key aerosol particle properties in a continental location in southern Africa. In close collaboration with the North-West University in South Africa this aim has now been achieved at the Welgegund measurement station. The other aims of this work were to determine the aerosol particle concentrations including their seasonal and diurnal variation and to study the most important aerosol particle sources in continental southern Africa. In this thesis the aerosol size distribution and its seasonal and diurnal variation is reported for different environments ranging from a clean rural background to an anthropogenically heavily influenced mining region in continental southern Africa. Atmospheric regional scale new particle formation has been observed at a world record high frequency and it dominates the diurnal

The capture of submicron particles by collector plates - Wind-tunnel investigations

International Nuclear Information System (INIS)

Gauthier, Daniel

1971-01-01

The deposition of submicron particles on collector plates parallel to the flow was studied experimentally in a wind-tunnel. The validity of a theoretical model based on brownian diffusion was investigated and its Inadequacies tested. The aerosol sample consisted of uranine particles (mean geometrical radius: about 0. 1 μm). The average flow speeds varied from 1 to 10 m/s and the length of the collector plates between 1 and 10 cm. Results showed that capture was mainly due to diffusion and was in good agreement with the theoretical model; however a noticeable deposit of particles on the front part of the collector edge was observed. Sedimentation was insignificant in almost all the cases. (author) [fr

One year online chemical speciation of submicron particulate matter (PM1) sampled at a French industrial and coastal site

Science.gov (United States)

Zhang, Shouwen; Riffault, Véronique; Dusanter, Sébastien; Augustin, Patrick; Fourmentin, Marc; Delbarre, Hervé

2015-04-01

The harbor of Dunkirk (Northern France) is surrounded by different industrial plants (metallurgy, petrochemistry, food processing, power plant, etc.), which emit gaseous and particulate pollutants such as Volatile Organic Compounds (VOCs), oxides of nitrogen (NOx) and sulfur (SO2), and submicron particles (PM1). These emissions are poorly characterized and their impact on neighboring urban areas has yet to be assessed. Studies are particularly needed in this type of complex environments to get a better understanding of PM1sources, especially from the industrial sector, their temporal variability, and their transformation. Several instruments, capable of real-time measurements (temporal resolution ≤ 30 min), were deployed at a site located downwind from the industrial area of Dunkirk for a one-year duration (July 2013-September 2014). An Aerosol Chemical Speciation Monitor (ACSM) and an Aethalometer monitored the main chemical species in the non-refractory submicron particles and black carbon, respectively. Concomitant measurements of trace gases and wind speed and direction were also performed. This dataset was analyzed considering four wind sectors, characteristics of marine, industrial, industrial-urban, and urban influences, and the different seasons. We will present a descriptive analysis of PM1, showing strong variations of ambient concentrations, as well as evidences of SO2 to SO4 gas-particle conversion when industrial plumes reached the monitoring site. The organic fraction measured by ACSM (37% of the total mass on average) was analyzed using a source-receptor model based on Positive Matrix Factorization (PMF) to identify chemical signatures of main emission sources and to quantify the contribution of each source to the PM1 budget given the wind sector. Four main factors were identified: hydrocarbon organic aerosol (HOA), oxygenated organic aerosol (OOA), biomass burning organic aerosol (BBOA) and cooking-like organic aerosol (COA). Overall, the total PM

Laser direct writing using submicron-diameter fibers.

Science.gov (United States)

Tian, Feng; Yang, Guoguang; Bai, Jian; Xu, Jianfeng; Hou, Changlun; Liang, Yiyong; Wang, Kaiwei

2009-10-26

In this paper, a novel direct writing technique using submicron-diameter fibers is presented. The submicron-diameter fiber probe serves as a tightly confined point source and it adopts micro touch mode in the process of writing. The energy distribution of direct writing model is analyzed by Three-Dimension Finite-Difference Time-Domain method. Experiments demonstrate that submicron-diameter fiber direct writing has some advantages: simple process, 350-nm-resolution (lower than 442-nm-wavelength), large writing area, and controllable width of lines. In addition, by altering writing direction of lines, complex submicron patterns can be fabricated.

Aerosol effects in radiation transfer

International Nuclear Information System (INIS)

Binenko, V.I.; Harshvardhan, H.

1993-01-01

The radiative properties and effects of aerosols are assessed for the following aerosol sources: relatively clean background aerosol, dust storms and dust outbreaks, anthropogenic pollution, and polluted cloud layers. Studies show it is the submicron aerosol fraction that plays a dominant radiative role in the atmosphere. The radiative effect of the aerosol depends not only on its loading but also on the underlying surface albedo and on solar zenith angle. It is only with highly reflecting surfaces such as Arctic ice that aerosols have a warming effect. Radiometric, microphysical, mineral composition, and refractive index measurements are presented for dust and in particular for the Saharan aerosol layer (SAL). Short-wave radiative heating of the atmosphere is caused by the SAL and is due mainly to absorption. However, the SAL does not contribute significantly to the long-wave thermal radiation budget. Field program studies of the radiative effects of aerosols are described. Anthropogenic aerosols deplete the incoming solar radiation. A case field study for a regional Ukrainian center is discussed. The urban aerosol causes a cooling of metropolitan centers, compared with outlying areas, during the day, which is followed by a warming trend at night. In another study, an increase in turbidity by a factor of 3 due to increased industrialization for Mexico City is noted, together with a drop in atmospheric transmission by 10% over a 50-year period. Numerous studies are cited that demonstrate that anthropogenic aerosols affect both the microphysical and radiative properties of clouds, which in turn affect regional climate. Particles acting as cloud nuclei are considered to have the greatest indirect effect on cloud absorptivity of short-wave radiation. Satellite observations show that low-level stratus clouds contaminated by ship exhaust at sea lead to an increase in cloud albedo

Methods to obtain radiolabelled monocrotaline

International Nuclear Information System (INIS)

Lame, M.W.; Morin, D.; Wilson, D.W.; Segall, H.J.

1996-01-01

Crotalaria spectabilis, a plant found in many areas of the world is associated with the pyrrolizidine alkaloid monocrotaline. Monocrotaline when injected subcutaneously in Sprague Dawley rats has been utilized for years to create a condition known to mimic pulmonary hypertension in humans. We attempted to determine the optimum conditions for the biosynthesis of radiolabelled monocrotaline. Our work describes the plant growth conditions and the time periods associated with the production of radiolabelled monocrotaline. In addition, the incorporation of 14 CO 2 or [2,3- 3 H]-putrescine dihydrochloride and the specific activity plus the amount(s) of recovered radiolabelled monocrotaline are discussed. We conclude that the most efficient and cost effective method for the biosynthesis of radiolabelled monocrotaline is still the utilization of 14 CO 2 . (author)

Radiolabelled cellular blood elements

International Nuclear Information System (INIS)

Sinzinger, H.

1990-01-01

This book reports on radiolabelled cellular blood elements, covering new advances made during the past several years, in particular the use of Tc-99 as a tracer for blood elements. Coverage extends to several radiolabelled monoclonal antibodies that are specific for blood components and may label blood elements in vivo

Methods to obtain radiolabelled monocrotaline

Energy Technology Data Exchange (ETDEWEB)

Lame, M.W.; Morin, D.; Wilson, D.W.; Segall, H.J. [University of California, Davis, CA (United States)

1996-12-01

Crotalaria spectabilis, a plant found in many areas of the world is associated with the pyrrolizidine alkaloid monocrotaline. Monocrotaline when injected subcutaneously in Sprague Dawley rats has been utilized for years to create a condition known to mimic pulmonary hypertension in humans. We attempted to determine the optimum conditions for the biosynthesis of radiolabelled monocrotaline. Our work describes the plant growth conditions and the time periods associated with the production of radiolabelled monocrotaline. In addition, the incorporation of {sup 14}CO{sub 2} or [2,3-{sup 3}H]-putrescine dihydrochloride and the specific activity plus the amount(s) of recovered radiolabelled monocrotaline are discussed. We conclude that the most efficient and cost effective method for the biosynthesis of radiolabelled monocrotaline is still the utilization of {sup 14}CO{sub 2}. (author).

Sources and atmospheric processing of organic aerosol in the Mediterranean: insights from aerosol mass spectrometer factor analysis

Directory of Open Access Journals (Sweden)

L. Hildebrandt

2011-12-01

Full Text Available Atmospheric particles were measured in the late winter (25 February–26 March 2009 at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2009. A quadrupole aerosol mass spectrometer (Q-AMS was employed to quantify the size-resolved chemical composition of non-refractory submicron aerosol, and a thermodenuder was used to analyze the organic aerosol (OA volatility. Complementary measurements included particle size distributions from a scanning mobility particle sizer, inorganic and organic particle composition from filter analysis, air ion concentrations, O₃, NO_x and NO_y concentrations, and meteorological measurements. Factor analysis was performed on the OA mass spectra, and the variability in OA composition could best be explained with three OA components. The oxygenated organic aerosol (OOA was similar in composition and volatility to the summertime OA previously measured at this site and may represent an effective endpoint in particle-phase oxidation of organics. The two other OA components, one associated with amines (Amine-OA and the other probably associated with the burning of olive branches (OB-OA, had very low volatility but were less oxygenated. Hydrocarbon-like organic aerosol (HOA was not detected. The absence of OB-OA and Amine-OA in the summer data may be due to lower emissions and/or photochemical conversion of these components to OOA.

Photothermal spectroscopy of aerosols

International Nuclear Information System (INIS)

Campillo, A.J.; Lin, H.B.

1981-04-01

In situ aerosol absorption spectroscopy was performed using two novel photothermal detection schemes. The first, based on a photorefractive effect and coherent detection, called phase fluctuation optical heterodyne (PFLOH) spectroscopy, could, depending on the geometry employed, yield particle specific or particle and gas absorption data. Single particles of graphite as small as 1 μm were detected in the particle specific mode. In another geometrical configuration, the total absorption (both gas and particle) of submicron sized aerosols of ammonium sulfate particles in equilibrium with gaseous ammonia and water vapor were measured at varying CO 2 laser frequencies. The specific absorption coefficient for the sulfate ion was measured to be 0.5 m 2 /g at 1087 cm -1 . The absorption coefficient sensitivity of this scheme was less than or equal to 10 -8 cm -1 . The second scheme is a hybrid visible Mie scattering scheme incorporating photothermal modulation. Particle specific data on ammonium sulfate droplets were obtained. For chemically identical species, the relative absorption spectrum versus laser frequency can be obtained for polydisperse aerosol distributions directly from the data without the need for complex inverse scattering calculations

Microphysical and chemical characteristics of near-water aerosol over White and Kara Seas

Science.gov (United States)

Terpugova, S. A.; Polkin, V. V.; Panchenko, M. V.; Golobokova, L. P.; Kozlov, V. S.; Shmargunov, V. P.; Shevchenko, V. P.; Lisitzin, A. P.

2009-04-01

The results are presented of five-year-long (2003-2007) study of the spatial - temporal variability of the near-water aerosol in the water area of White and Kara Seas (55, 64, 71 and 80-th cruises of RV "Professor Shtockman"; 53 and 54-th cruises of RV "Akademik Mstislav Keldysh"). Measurements of aerosol microphysical characteristics were carried out by means of the automated mobile aerosol complex consisting of nephelometer, photoelectric counter and aethalometer. The aerosol disperse composition was studied with photoelectric counter in 256 size intervals from 0.4 to 10 m. About 1500 series of measurements were carried out in White Sea, and about 1400 series in Kara Sea. Chemical characteristics of aerosol were determined from samples collected on aerosol filters (92 samples were collected in White Sea and 48 in Kara Sea). The ion composition was determined under laboratory conditions. The H+, Na+, K+, Ca2+, Mg2+, NH4+, Cl-, NO3-, HCO3-, SO42- ions were under examination. Comparing aerosol characteristics of two seas, one can note that the mean values of the aerosol content parameters in Kara Sea are less than in White Sea. The ratio of the aerosol mass concentration are from 2 (Yamal Peninsula, northern part of Novaya Zemlya) to 9 times (Blagopoluchia Bay, Ob' Gulf). The differences in the concentration of black carbon vary from 3 (Yamal Peninsula) to 17 times (Blagopoluchia Bay). The differences in the aerosol number concentration NA are not so big. The values NA near Kara Gate, Yamal Peninsula and northern part of Novaya Zemlya are practically the same as in White Sea. The concentration NA at Ob' gulf is one order of magnitude less than in White sea. The obtained aerosol volume size distributions were approximated by the sums of two fractions, submicron and coarse, with lognormal size distributions. The mean volume size distribution of submicron fraction in White Sea is approximated by the distribution with the variance of the radius logarithm s=0.6 and modal

In vitro evaluation of radio-labeled aerosol delivery via a variable-flow infant CPAP system.

Science.gov (United States)

Farney, Kimberly D; Kuehne, Brandon T; Gibson, Laurie A; Nelin, Leif D; Shepherd, Edward G

2014-03-01

Nasal CPAP is widely used in neonatal ICUs. Aerosolized medications such as inhaled steroids and β agonists are commonly administered in-line through nasal CPAP, especially to infants with bronchopulmonary dysplasia. We hypothesized that aerosol delivery to the lungs via variable-flow nasal CPAP in an in vitro model would be unreliable, and that the delivery would depend on the position of the aerosol generator within the nasal CPAP circuit. We used a system that employed a test lung placed in a plastic jar and subjected to negative pressure. Simulated inspiration effort was measured with a heated-wire anemometer. We used technetium-99m-labeled diethylene triamine penta-acetic acid as our aerosol. The nebulizer was placed either close to the humidifier or close to the nasal prongs in the circuit, and patient effort was simulated with a minute ventilation of 0.4 L/min. Relative aerosol delivery to the infant test lung with the nebulizer close to the humidifier was extremely low (0.3 ± 0.4%), whereas placing the nebulizer close to the nasal prongs resulted in significantly (P CPAP was negligible in this in vitro setup; however, such delivery was significantly improved by locating the aerosol generator closer to the nasal CPAP interface.

Radiolabeled derivatives of folic acid

International Nuclear Information System (INIS)

1980-01-01

Derivatives of folic acid are described, in which the α-carboxyl group is substituted with an amino compound having an aromatic or heterocyclic ring substituent which is capable of being radiolabelled. Particularly mentioned as a radiolabel is 125 I. (author)

99mTc-DTPA aerosol for same-day post-perfusion ventilation imaging: Results of a multicentre study

International Nuclear Information System (INIS)

Koehn, H.; Koenig, B.; Bachmayr, S.; Markt, B.; Eber, O.; Lind, P.; Galvan, G.; Rettenbacher, L.; Holm, C.; Ogris, E.

1993-01-01

A multicentre study was performed in an attempt to evaluate a submicronic technetium-99m diethylene triamine penta-acetic acid aerosol generated by a newly developed delivery system, the aerosol production equipment (APE nebulizer), for same-day post-perfusion ventilation imaging in patients with clinically suspected pulmonary embolism. Quantitative comparison between the DTPA aerosol and krypton gas demonstrated a close correlation with respect to regional pulmonary distribution of activity and peripheral lung penetration (n=14, r=0.94, P 99m Tc-labelled DTPA aerosol is well suited for fast same-day post-perfusion ventilation imaging in patients with clinical suspicion of pulmonary embolism. (orig.)

Submicron aerosol distributions and CCN activity measured in and around the Korean Peninsula during KORUS-AQ

Science.gov (United States)

Park, M.; Kim, N.; Yum, S. S.; Thornhill, K. L., II; Anderson, B. E.; Kim, D. S.; Kim, H. J.; Jeon, H. E.; Park, Y. S.; Lee, S. B.

2017-12-01

KORUS-AQ is a field campaign aimed at investigating formation of ozone and aerosol and interactions between chemistry, transport and various sources in the Korean Peninsula which is the region affected both by long-range transport and local emission. Aerosol number concentration and size distribution, and CCN number concentration were measured on board the NASA DC-8 research aircraft and at a ground site at Olympic Park in Seoul, capital city of Korea during the KORUS-AQ campaign (May 2nd to June 10th, 2017). There were 20 flights during the KORUS-AQ campaign and total flight time was about 150 hours. CCN counter (CCNC) on the airborne platform was operated at the fixed internal supersaturation of 0.6% and CCNC at the ground site was operated at five different supersaturations (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%). Aerosol hygroscopic parameter κ was also estimated from CCN number concentration and aerosol size distribution. Airborne measurements showed a large spatio-temporal variation of aerosol number concentration and CCN activity in and around the Korean peninsula, and the ground measurements also showed a large temporal variation. The campaign period can be classified into long-range transport dominant cases, local emission dominant cases due to stagnant air mass, and others. Aerosol number concentration in the Korean Peninsula measured in stagnant air mass period was higher than those in long-range transport period, but CCN number concentration showed an opposite tendency. Both aerosol and CCN number concentrations over the Yellow Sea in local emission period were slightly higher than those in long-range transport period. Since CCN activity is different depending on time and space, our focus is on understanding how CCN activity and aerosol hygroscopicity vary with the source of aerosol. Comprehensive analysis results will be shown at the conference.

Sensitivity of depositions to the size and hygroscopicity of Cs-bearing aerosols released by the Fukushima Nuclear Accident

Energy Technology Data Exchange (ETDEWEB)

Kajino, Mizuo [Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052 (Japan); RIKEN Advanced Institute for Computational Science, 7-1-26 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan); Adachi, Kouji; Sekiyama, Tsuyoshi T.; Zaizen, Yuji; Igarashi, Yasuhito [Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052 (Japan)

2014-07-01

We recently revealed that the micro-physical properties of aerosols carrying the radioactive Cs released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) at an early stage (March 14-15, 2011) of the accident could be very different from what we assumed previously: super-micron and non-hygroscopic at the early stage, whereas sub-micron and hygroscopic afterwards (at least later than March 20-22). In the study, two sensitivity simulations with the two different aerosol micro-physical properties were conducted using a regional scale meteorology- chemical transport model (NHM-Chem). The impact of the difference was quite significant. 17% (10-3%) of the radioactive Cs fell onto the ground by dry (wet) deposition processes, and the rest was deposited into the ocean or was transported out of the model domain, which is central and northern part of the main land of Japan under the assumption that Cs-bearing aerosols are non-hygroscopic and super-micron. On the other hand, 5.7% (11.3%) fell onto the ground by dry (wet) deposition, for the cases under the assumption that the Cs-bearing aerosols are hygroscopic and sub-micron. For the accurate simulation of the deposition of radionuclides, knowledge of the aerosol micro-physical properties is essential as well as the accuracy of the simulated wind fields and precipitation patterns. (authors)

Aged organic aerosol in the Eastern Mediterranean: the Finokalia Aerosol Measurement Experiment – 2008

Directory of Open Access Journals (Sweden)

L. Hildebrandt

2010-05-01

Full Text Available Aged organic aerosol (OA was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2008 (FAME-2008, which was part of the EUCAARI intensive campaign of May 2008. The site at Finokalia is influenced by air masses from different source regions, including long-range transport of pollution from continental Europe. A quadrupole aerosol mass spectrometer (Q-AMS was employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM₁, and to estimate the extent of oxidation of the organic aerosol. Factor analysis was used to gain insights into the processes and sources affecting the OA composition. The particles were internally mixed and liquid. The largest fraction of the dry NR-PM₁ sampled was ammonium sulfate and ammonium bisulfate, followed by organics and a small amount of nitrate. The variability in OA composition could be explained with two factors of oxygenated organic aerosol (OOA with differing extents of oxidation but similar volatility. Hydrocarbon-like organic aerosol (HOA was not detected. There was no statistically significant diurnal variation in the bulk composition of NR-PM₁ such as total sulfate or total organic aerosol concentrations. However, the OA composition exhibited statistically significant diurnal variation with more oxidized OA in the afternoon. The organic aerosol was highly oxidized, regardless of the source region. Total OA concentrations also varied little with source region, suggesting that local sources had only a small effect on OA concentrations measured at Finokalia. The aerosol was transported for about one day before arriving at the site, corresponding to an OH exposure of approximately 4×10¹¹ molecules cm⁻³ s. The constant extent of oxidation suggests that atmospheric aging results in a highly oxidized OA at these OH exposures, regardless of the aerosol source.

Primary and secondary aerosols in Beijing in winter: sources, variations and processes

Science.gov (United States)

Sun, Yele; Du, Wei; Fu, Pingqing; Wang, Qingqing; Li, Jie; Ge, Xinlei; Zhang, Qi; Zhu, Chunmao; Ren, Lujie; Xu, Weiqi; Zhao, Jian; Han, Tingting; Worsnop, Douglas R.; Wang, Zifa

2016-07-01

Winter has the worst air pollution of the year in the megacity of Beijing. Despite extensive winter studies in recent years, our knowledge of the sources, formation mechanisms and evolution of aerosol particles is not complete. Here we have a comprehensive characterization of the sources, variations and processes of submicron aerosols that were measured by an Aerodyne high-resolution aerosol mass spectrometer from 17 December 2013 to 17 January 2014 along with offline filter analysis by gas chromatography/mass spectrometry. Our results suggest that submicron aerosols composition was generally similar across the winter of different years and was mainly composed of organics (60 %), sulfate (15 %) and nitrate (11 %). Positive matrix factorization of high- and unit-mass resolution spectra identified four primary organic aerosol (POA) factors from traffic, cooking, biomass burning (BBOA) and coal combustion (CCOA) emissions as well as two secondary OA (SOA) factors. POA dominated OA, on average accounting for 56 %, with CCOA being the largest contributor (20 %). Both CCOA and BBOA showed distinct polycyclic aromatic hydrocarbons (PAHs) spectral signatures, indicating that PAHs in winter were mainly from coal combustion (66 %) and biomass burning emissions (18 %). BBOA was highly correlated with levoglucosan, a tracer compound for biomass burning (r2 = 0.93), and made a considerable contribution to OA in winter (9 %). An aqueous-phase-processed SOA (aq-OOA) that was strongly correlated with particle liquid water content, sulfate and S-containing ions (e.g. CH2SO2+) was identified. On average aq-OOA contributed 12 % to the total OA and played a dominant role in increasing oxidation degrees of OA at high RH levels (> 50 %). Our results illustrate that aqueous-phase processing can enhance SOA production and oxidation states of OA as well in winter. Further episode analyses highlighted the significant impacts of meteorological parameters on aerosol composition, size

Primary and secondary aerosols in Beijing in winter: sources, variations and processes

Directory of Open Access Journals (Sweden)

Y. Sun

2016-07-01

Full Text Available Winter has the worst air pollution of the year in the megacity of Beijing. Despite extensive winter studies in recent years, our knowledge of the sources, formation mechanisms and evolution of aerosol particles is not complete. Here we have a comprehensive characterization of the sources, variations and processes of submicron aerosols that were measured by an Aerodyne high-resolution aerosol mass spectrometer from 17 December 2013 to 17 January 2014 along with offline filter analysis by gas chromatography/mass spectrometry. Our results suggest that submicron aerosols composition was generally similar across the winter of different years and was mainly composed of organics (60 %, sulfate (15 % and nitrate (11 %. Positive matrix factorization of high- and unit-mass resolution spectra identified four primary organic aerosol (POA factors from traffic, cooking, biomass burning (BBOA and coal combustion (CCOA emissions as well as two secondary OA (SOA factors. POA dominated OA, on average accounting for 56 %, with CCOA being the largest contributor (20 %. Both CCOA and BBOA showed distinct polycyclic aromatic hydrocarbons (PAHs spectral signatures, indicating that PAHs in winter were mainly from coal combustion (66 % and biomass burning emissions (18 %. BBOA was highly correlated with levoglucosan, a tracer compound for biomass burning (r2 = 0.93, and made a considerable contribution to OA in winter (9 %. An aqueous-phase-processed SOA (aq-OOA that was strongly correlated with particle liquid water content, sulfate and S-containing ions (e.g. CH2SO2+ was identified. On average aq-OOA contributed 12 % to the total OA and played a dominant role in increasing oxidation degrees of OA at high RH levels (> 50 %. Our results illustrate that aqueous-phase processing can enhance SOA production and oxidation states of OA as well in winter. Further episode analyses highlighted the significant impacts of meteorological parameters on

Clouds and aerosols in Puerto Rico - a new evaluation

Science.gov (United States)

Allan, J. D.; Baumgardner, D.; Raga, G. B.; Mayol-Bracero, O. L.; Morales-García, F.; García-García, F.; Montero-Martínez, G.; Borrmann, S.; Schneider, J.; Mertes, S.; Walter, S.; Gysel, M.; Dusek, U.; Frank, G. P.; Krämer, M.

2008-03-01

The influence of aerosols, both natural and anthropogenic, remains a major area of uncertainty when predicting the properties and behaviour of clouds and their influence on climate. In an attempt to better understand warm cloud formation in a tropical marine environment, a period of intensive measurements took place in December 2004 in Puerto Rico, using some of the latest developments in online instrumentation such as aerosol mass spectrometers, cloud condensation nuclei counters and a hygroscopicity tandem differential mobility analyser. Simultaneous online measurements of aerosol size distributions, composition, hygroscopicity and optical properties were made near the lighthouse of Cape San Juan in the north-eastern corner of the island and at the top of East Peak mountain (1040 m a.s.l.), the two sites separated by 17 km. Additional measurements of the cloud droplet residual and interstitial aerosol properties were made at the mountain site, accompanied by measurements of cloud droplet size distributions, liquid water content and the chemical composition of cloud and rain water samples. Both aerosol composition and cloud properties were found to be sensitive to wind sector. Air from the east-northeast (ENE) was mostly free of anthropogenic influences, the submicron fraction being mainly composed of non-sea salt sulphate, while that from the east-southeast (ESE) was found to be moderately influenced by populated islands upwind, adding smaller (residual particles and concentrations of cloudwater nitrate, sulphate and insoluble material increased during polluted conditions. Previous studies in Puerto Rico had reported the presence of a significant non-anthropogenic organic fraction in the aerosols measured and concluded that this was a factor controlling the in situ cloud properties. However, this was not observed in our case. In contrast to the 1.00±0.14 μg m-3 of organic carbon measured in 1992 and 1995, the organic matter measured in the current study of 0

Experiments probing the influence of air exchange rates on secondary organic aerosols derived from indoor chemistry

DEFF Research Database (Denmark)

Weschler, Charles J.; Shields, H.C.

2003-01-01

Reactions between ozone and terpenes have been shown to increase the concentrations of submicron particles in indoor settings. The present study was designed to examine the influence of air exchange rates on the concentrations of these secondary organic aerosols as well as on the evolution...

Submicron particle mass concentrations and sources in the Amazonian wet season (AMAZE-08)

Energy Technology Data Exchange (ETDEWEB)

Chen, Q.; Farmer, D. K.; Rizzo, L. V.; Pauliqueivis, T.; Kuwata, Mikinori; Karl, Thomas G.; Guenther, Alex B.; Allan, James D.; Coe, H.; Andreae, M. O.; Poeschl, U.; Jiminez, J. L.; Artaxo, Paulo; Martin, Scot T.

2015-01-01

Real-time mass spectra of non-refractory component of submicron aerosol particles were recorded in a tropical rainforest in the central Amazon basin during the wet season of 2008, as a part of the Amazonian Aerosol Characterization Experiment (AMAZE-08). Organic components accounted on average for more than 80% of the non-refractory submicron particle mass concentrations during the period of measurements. Ammonium was present in sufficient quantities to halfway neutralize sulfate. In this acidic, isoprene-dominated, low-NOx environment the high-resolution mass spectra as well as mass closures with ion chromatography measurements did not provide evidence for significant contributions of organosulfate species, at least at concentrations above uncertainty levels. Positive-matrix factorization of the time series of particle mass spectra identified four statistical factors to account for the variance of the signal intensities of the organic constituents: a factor HOA having a hydrocarbon-like signature and identified as regional emissions of primary organic material, a factor OOA-1 associated with fresh production of secondary organic material by a mechanism of BVOC oxidation followed by gas-to-particle conversion, a factor OOA-2 consistent with reactive uptake of isoprene oxidation products, especially epoxydiols by acidic particles, and a factor OOA-3 associated with long range transport and atmospheric aging. The OOA-1, -2, and -3 factors had progressively more oxidized signatures. Diameter-resolved mass spectral markers also suggested enhanced reactive uptake of isoprene oxidation products to the accumulation mode for the OOA-2 factor, and such size partitioning can be indicative of in-cloud process. The campaign-average factor loadings were in a ratio of 1.1:1.0 for the OOA-1 compared to the OOA-2 pathway, suggesting the comparable importance of gas-phase compared to particle-phase (including cloud waters) production pathways of secondary organic material during

Rapid Measurements of Aerosol Size Distribution and Hygroscopic Growth via Image Processing with a Fast Integrated Mobility Spectrometer (FIMS)

Science.gov (United States)

Wang, Y.; Pinterich, T.; Spielman, S. R.; Hering, S. V.; Wang, J.

2017-12-01

Aerosol size distribution and hygroscopicity are among key parameters in determining the impact of atmospheric aerosols on global radiation and climate change. In situ submicron aerosol size distribution measurements commonly involve a scanning mobility particle sizer (SMPS). The SMPS scanning time is in the scale of minutes, which is often too slow to capture the variation of aerosol size distribution, such as for aerosols formed via nucleation processes or measurements onboard research aircraft. To solve this problem, a Fast Integrated Mobility Spectrometer (FIMS) based on image processing was developed for rapid measurements of aerosol size distributions from 10 to 500 nm. The FIMS consists of a parallel plate classifier, a condenser, and a CCD detector array. Inside the classifier an electric field separates charged aerosols based on electrical mobilities. Upon exiting the classifier, the aerosols pass through a three stage growth channel (Pinterich et al. 2017; Spielman et al. 2017), where aerosols as small as 7 nm are enlarged to above 1 μm through water or heptanol condensation. Finally, the grown aerosols are illuminated by a laser sheet and imaged onto a CCD array. The images provide both aerosol concentration and position, which directly relate to the aerosol size distribution. By this simultaneous measurement of aerosols with different sizes, the FIMS provides aerosol size spectra nearly 100 times faster than the SMPS. Recent deployment onboard research aircraft demonstrated that the FIMS is capable of measuring aerosol size distributions in 1s (Figure), thereby offering a great advantage in applications requiring high time resolution (Wang et al. 2016). In addition, the coupling of the FIMS with other conventional aerosol instruments provides orders of magnitude more rapid characterization of aerosol optical and microphysical properties. For example, the combination of a differential mobility analyzer, a relative humidity control unit, and a FIMS was

Experiments probing the influence of air exchange rates on secondary organic aerosols derived from indoor chemistry

DEFF Research Database (Denmark)

Weschler, Charles J.; Shields, H.C.

2003-01-01

Reactions between ozone and terpenes have been shown to increase the concentrations of submicron particles in indoor settings. The present study was designed to examine the influence of air exchange rates on the concentrations of these secondary organic aerosols as well as on the evolution of the...

Photoacoustics of single laser-trapped nanodroplets for the direct observation of nanofocusing in aerosol photokinetics

Science.gov (United States)

Cremer, Johannes W.; Thaler, Klemens M.; Haisch, Christoph; Signorell, Ruth

2016-03-01

Photochemistry taking place in atmospheric aerosol droplets has a significant impact on the Earth's climate. Nanofocusing of electromagnetic radiation inside aerosols plays a crucial role in their absorption behaviour, since the radiation flux inside the droplet strongly affects the activation rate of photochemically active species. However, size-dependent nanofocusing effects in the photokinetics of small aerosols have escaped direct observation due to the inability to measure absorption signatures from single droplets. Here we show that photoacoustic measurements on optically trapped single nanodroplets provide a direct, broadly applicable method to measure absorption with attolitre sensitivity. We demonstrate for a model aerosol that the photolysis is accelerated by an order of magnitude in the sub-micron to micron size range, compared with larger droplets. The versatility of our technique promises broad applicability to absorption studies of aerosol particles, such as atmospheric aerosols where quantitative photokinetic data are critical for climate predictions.

Aerosol composition and sources during the Chinese Spring Festival: fireworks, secondary aerosol, and holiday effects

Science.gov (United States)

Jiang, Q.; Sun, Y. L.; Wang, Z.; Yin, Y.

2015-06-01

Aerosol particles were characterized by an Aerodyne aerosol chemical speciation monitor along with various collocated instruments in Beijing, China, to investigate the role of fireworks (FW) and secondary aerosol in particulate pollution during the Chinese Spring Festival of 2013. Three FW events, exerting significant and short-term impacts on fine particles (PM2.5), were observed on the days of Lunar New Year, Lunar Fifth Day, and Lantern Festival. The FW were shown to have a large impact on non-refractory potassium, chloride, sulfate, and organics in submicron aerosol (PM1), of which FW organics appeared to be emitted mainly in secondary, with its mass spectrum resembling that of secondary organic aerosol (SOA). Pollution events (PEs) and clean periods (CPs) alternated routinely throughout the study. Secondary particulate matter (SPM = SOA + sulfate + nitrate + ammonium) dominated the total PM1 mass on average, accounting for 63-82% during nine PEs in this study. The elevated contributions of secondary species during PEs resulted in a higher mass extinction efficiency of PM1 (6.4 m2 g-1) than during CPs (4.4 m2 g-1). The Chinese Spring Festival also provides a unique opportunity to study the impact of reduced anthropogenic emissions on aerosol chemistry in the city. Primary species showed ubiquitous reductions during the holiday period with the largest reduction being in cooking organic aerosol (OA; 69%), in nitrogen monoxide (54%), and in coal combustion OA (28%). Secondary sulfate, however, remained only slightly changed, and the SOA and the total PM2.5 even slightly increased. Our results have significant implications for controlling local primary source emissions during PEs, e.g., cooking and traffic activities. Controlling these factors might have a limited effect on improving air quality in the megacity of Beijing, due to the dominance of SPM from regional transport in aerosol particle composition.

Ultrahigh-strength submicron-sized metallic glass wires

International Nuclear Information System (INIS)

Wang, Y.B.; Lee, C.C.; Yi, J.; An, X.H.; Pan, M.X.; Xie, K.Y.; Liao, X.Z.; Cairney, J.M.; Ringer, S.P.; Wang, W.H.

2014-01-01

In situ deformation experiments were performed in a transmission electron microscope to investigate the mechanical properties of submicron-sized Pd 40 Cu 30 Ni 10 P 20 metallic glass (MG) wires. Results show that the submicron-sized MG wires exhibit intrinsic ultrahigh tensile strength of ∼2.8 GPa, which is nearly twice as high as that in their bulk counterpart, and ∼5% elastic strain approaching the elastic limits. The tensile strength, engineering strain at failure and deformation mode of the submicron-sized MG wires depend on the diameter of the wires

Seasonal variations of ultra-fine and submicron aerosols in Taipei, Taiwan: implications for particle formation processes in a subtropical urban area

Directory of Open Access Journals (Sweden)

H. C. Cheung

2016-02-01

Full Text Available The aim of this study is to investigate the seasonal variations in the physicochemical properties of atmospheric ultra-fine particles (UFPs, d ≤ 100 nm and submicron particles (PM1, d ≤ 1 µm in an east Asian urban area, which are hypothesized to be affected by the interchange of summer and winter monsoons. An observation experiment was conducted at TARO (Taipei Aerosol and Radiation Observatory, an urban aerosol station in Taipei, Taiwan, from October 2012 to August 2013. The measurements included the mass concentration and chemical composition of UFPs and PM1, as well as the particle number concentration (PNC and the particle number size distribution (PSD with size range of 4–736 nm. The results indicated that the mass concentration of PM1 was elevated during cold seasons with a peak level of 18.5 µg m−3 in spring, whereas the highest concentration of UFPs was measured in summertime with a mean of 1.64 µg m−3. Moreover, chemical analysis revealed that the UFPs and PM1 were characterized by distinct composition; UFPs were composed mostly of organics, whereas ammonium and sulfate were the major constituents of PM1. The seasonal median of total PNCs ranged from 13.9  ×  103 cm−3 in autumn to 19.4  ×  103 cm−3 in spring. Median concentrations for respective size distribution modes peaked in different seasons. The nucleation-mode PNC (N4 − 25 peaked at 11.6  ×  103 cm−3 in winter, whereas the Aitken-mode (N25 − 100 and accumulation-mode (N100 − 736 PNC exhibited summer maxima at 6.0  ×  103 and 3.1  ×  103 cm−3, respectively. The change in PSD during summertime was attributed to the enhancement in the photochemical production of condensable organic matter that, in turn, contributed to the growth of aerosol particles in the atmosphere. In addition, clear photochemical production of particles was observed, mostly in the summer season

Overview and preliminary results of the Surface Ocean Aerosol Production (SOAP campaign

Directory of Open Access Journals (Sweden)

C. S. Law

2017-11-01

, contaminant markers and a common aerosol inlet facilitated multi-sensor measurement of uncontaminated air. Aerosol characterization identified variable Aitken mode and consistent submicron-sized accumulation and coarse modes. Submicron aerosol mass was dominated by secondary particles containing ammonium sulfate/bisulfate under light winds, with an increase in sea salt under higher wind speeds. MBL measurements and chamber experiments identified a significant organic component in primary and secondary aerosols. Comparison of SOAP aerosol number and size distributions reveals an underprediction in GLOMAP (GLObal Model of Aerosol Processes-mode aerosol number in clean marine air masses, suggesting a missing marine aerosol source in the model. The SOAP data will be further examined for evidence of nucleation events and also to identify relationships between MBL composition and surface ocean biogeochemistry that may provide potential proxies for aerosol precursors and production.

Submicron Emulsions and Their Applications in Oral Delivery.

Science.gov (United States)

Mundada, Veenu; Patel, Mitali; Sawant, Krutika

2016-01-01

A "submicron emulsion" is an isotropic mixture of drug, lipids, and surfactants, usually with hydrophilic cosolvents and with droplet diameters ranging from 10 to 500 nm. Submicron emulsions are of increasing interest in medicine due to their kinetic stability, high solubilizing capacity, and tiny globule size. Because of these properties, they have been applied in various fields, such as personal care, cosmetics, health care, pharmaceuticals, and agrochemicals. Submicron emulsions are by far the most advanced nanoparticulate systems for the systemic delivery of biologically active agents for controlled drug delivery and targeting. They are designed mainly for pharmaceutical formulations suitable for various routes of administration like parenteral, ocular, transdermal, and oral. This review article describes the marked potential of submicron emulsions for oral drug delivery owing to their numerous advantages like reduced first pass metabolism, inhibition of P-glycoprotein efflux system, and enhanced absorption via intestinal lymphatic pathway. To overcome the limitations of liquid dosage forms, submicron emulsions can be formulated into solid dosage forms such as solid self-emulsifying systems. This article covers various types of submicron emulsions like microemulsion, nanoemulsion, and self-emulsifying drug delivery system (SEDDS), and their potential pharmaceutical applications in oral delivery with emphasis on their advantages, limitations, and advancements.

Photoacoustic measurements of photokinetics in single optically trapped aerosol droplets

Science.gov (United States)

Covert, Paul; Cremer, Johannes; Signorell, Ruth; Thaler, Klemens; Haisch, Christoph

2017-04-01

It is well established that interaction of light with atmospheric aerosols has a large impact on the Earth's climate. However, uncertainties in the magnitude of this impact remain large, due in part to broad distributions of aerosol size, composition, and chemical reactivity. In this context, photoacoustic spectroscopy is commonly used to measure light absorption by aerosols. Here, we present photoacoustic measurements of single, optically-trapped nanodroplets to reveal droplet size-depencies of photochemical and physical processes. Theoretical considerations have pointed to a size-dependence in the magnitude and phase of the photoacoustic response from aerosol droplets. This dependence is thought to originate from heat transfer processes that are slow compared to the acoustic excitation frequency. In the case of a model aerosol, our measurements of single particle absorption cross-section versus droplet size confirm these theoretical predictions. In a related study, using the same model aerosol, we also demonstrate a droplet size-dependence of photochemical reaction rates [1]. Within sub-micron sized particles, photolysis rates were observed to be an order of magnitude greater than those observed in larger droplets. [1] J. W. Cremer, K. M. Thaler, C. Haisch, and R. Signorell. Photoacoustics of single laser-trapped nanodroplets for the direct observation of nanofocusing in aerosol photokinetics. Nat. Commun., 7:10941, 2016.

Fog and Cloud Induced Aerosol Modification Observed by AERONET

Science.gov (United States)

Eck, T. F.; Holben, B. N.; Reid, J. S.; Giles, D. M.; Rivas, M. A.; Singh, R. P.; Tripathi, S. N.; Bruegge, C. J.; Platnick, S. E.; Arnold, G. T.;

Simultaneous aerosol size distribution and turbidity measurements over St. Louis during METROMEX 1975

International Nuclear Information System (INIS)

Laulainen, N.S.; Alkezweeny, A.J.; Thorp, J.M.

1978-01-01

An experiment designed to measure aerosol size distributions and turbidity simultaneously over a metropolitan area is described. The particle volume size distributions measured in the city plume are found to be bimodal, with the total particle volume in the fine or submicron mode decreasing dramatically above the inversion. Aerosol extinction coefficients derived from sunphotometer optical depth measurements at four wavelengths are compared to those calculated from the measured size distributions using Mie theory with several different particle refractive indices. The accuracy of the experimental method for determining the aerosol extinction coefficient prevented any meaningful choice of the real part of particle refractive index between 1.5--1.6 and an imaginary part between 0 and -0.1i. Improvements to this type of experiment are discussed

Chemical composition, sources and evolution processes of aerosol at an urban site in Yangtze River Delta, China during wintertime

Science.gov (United States)

Zhang, Yunjiang; Tang, Lili; Yu, Hongxia; Wang, Zhuang; Sun, Yele; Qin, Wei; Chen, Wentai; Chen, Changhong; Ding, Aijun; Wu, Jing; Ge, Shun; Chen, Cheng; Zhou, Hong-cang

2015-12-01

To investigate the composition, sources and evolution processes of submicron aerosol during wintertime, a field experiment was conducted during December 1-31, 2013 in urban Nanjing, a megacity in Yangtze River Delta of China. Non-refractory submicron aerosol (NR-PM1) species were measured with an Aerodyne Aerosol Chemical Speciation Monitor. NR-PM1 is dominated by secondary inorganic aerosol (55%) and organic aerosol (OA, 42%) during haze periods. Six OA components were identified by positive matrix factorization of the OA mass spectra. The hydrocarbon-like OA and cooking-related OA represent the local traffic and cooking sources, respectively. A highly oxidized factor related to biomass burning OA accounted for 15% of the total OA mass during haze periods. Three types of oxygenated OA (OOA), i.e., a less-oxidized OOA (LO-OOA), a more-oxidized OOA (MO-OOA), and a low-volatility OOA (LV-OOA), were identified. LO-OOA is likely associated with fresh urban secondary OA. MO-OOA likely represents photochemical products showing a similar diurnal cycle to nitrate with a pronounced noon peak. LV-OOA appears to be a more oxidized factor with a pronounced noon peak. The OA composition is dominated by secondary species, especially during haze events. LO-OOA, MO-OOA and LV-OOA on average account for 11%, (18%), 24% (21%) and 23% (18%) of the total OA mass for the haze (clean) periods respectively. Analysis of meteorological influence suggested that regional transport from the northern and southeastern areas of the city is responsible for large secondary and low-volatility aerosol formation.

Ultrasonic-resonator-combined apparatus for purifying nuclear aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Hou, Suxia; Zhang, Quanhu; Li, Sufen; Chen, Chen; Su, Xianghua [Xi' an Hi-Tech Institute, Xi' an (China)

2017-12-15

The radiation hazards of radionuclides in the air arising from the storage room of nuclear devices to the operators cannot be ignored. A new ultrasonic-resonator-combined method for purifying nuclear aerosol particles is introduced. To remove particles with diameters smaller than 0.3 μm, an ultrasonic chamber is induced to agglomerate these submicron particles. An apparatus which is used to purify the nuclear aerosol particles is described in the article. The apparatus consists of four main parts: two filtering systems, an ultrasonic chamber and a high-pressure electrostatic precipitator system. Finally, experimental results demonstrated the effectiveness of the implementation of the ultrasonic resonators. The feasibility of the method is proven by its application to the data analysis of the experiments.

Aerosol comparisons between sunphotometry / sky radiometry and the GEOS-Chem model

Science.gov (United States)

Chaubey, J. P.; Hesaraki, S.; O'Neill, N. T.; Saha, A.; Martin, R.; Lesins, G. B.; Abboud, I.

2014-12-01

Comparisons of aerosol optical depth (AOD), spectral AOD parameters and microphysical parameters derived from AEROCAN / AERONET sunphotometer / sky radiometer data acquired over Canada were compared with GEOS-Chem (Geos5,v9-01-03) estimations. The Canadian sites were selected so as to encompass a representative variety of different aerosol types ranging from fine mode (submicron) pollution and smoke aerosols, coarse mode (supermicron) dust, fine and coarse mode marine aerosols, volcanic (fine mode) sulfates and volcanic (coarse mode) ash, etc). A particular focus was placed on comparisons at remote Canadian sites with a further focus on Arctic sites. The analysis included meteorological-scale event comparisons as well as seasonal and yearly comparisons on a climatological scale. The investigations were given a further aerosol type context by comparing optical retrievals of fine and coarse mode AOD with the AODs of the different aerosol types predicted by GEOS-Chem. The effects of temporal and spectral cloud screening of the sunphotometer data on the quality and robustness of these comparisons was the object of an important supporting investigation. The results of this study will be presented for a 3 year period from 2009 to 2011.

Aerosol Optical Properties Measured Onboard the Ronald H. Brown During ACE Asia as a Function of Aerosol Chemical Composition and Source Region

Science.gov (United States)

Quinn, P. K.; Coffman, D. J.; Bates, T. S.; Welton, E. J.; Covert, D. S.; Miller, T. L.; Johnson, J. E.; Maria, S.; Russell, L.; Arimoto, R.

2004-01-01

During the ACE Asia intensive field campaign conducted in the spring of 2001 aerosol properties were measured onboard the R/V Ronald H. Brown to study the effects of the Asian aerosol on atmospheric chemistry and climate in downwind regions. Aerosol properties measured in the marine boundary layer included chemical composition; number size distribution; and light scattering, hemispheric backscattering, and absorption coefficients. In addition, optical depth and vertical profiles of aerosol 180 deg backscatter were measured. Aerosol within the ACE Asia study region was found to be a complex mixture resulting from marine, pollution, volcanic, and dust sources. Presented here as a function of air mass source region are the mass fractions of the dominant aerosol chemical components, the fraction of the scattering measured at the surface due to each component, mass scattering efficiencies of the individual components, aerosol scattering and absorption coefficients, single scattering albedo, Angstrom exponents, optical depth, and vertical profiles of aerosol extinction. All results except aerosol optical depth and the vertical profiles of aerosol extinction are reported at a relative humidity of 55 +/- 5%. An over-determined data set was collected so that measured and calculated aerosol properties could be compared, internal consistency in the data set could be assessed, and sources of uncertainty could be identified. By taking into account non-sphericity of the dust aerosol, calculated and measured aerosol mass and scattering coefficients agreed within overall experimental uncertainties. Differences between measured and calculated aerosol absorption coefficients were not within reasonable uncertainty limits, however, and may indicate the inability of Mie theory and the assumption of internally mixed homogeneous spheres to predict absorption by the ACE Asia aerosol. Mass scattering efficiencies of non-sea salt sulfate aerosol, sea salt, submicron particulate organic

Radiolabeled peptides: experimental and clinical applications

International Nuclear Information System (INIS)

Thakur, M.L.; Pallela, V.R.

1998-01-01

Radiolabeled receptor specific biomolecules hold unlimited potential in nuclear medicine. During the past few years much attention has been drawn to the development radiolabeled peptides for a variety of diagnostic applications, as well as for therapy of malignant tumors. Although only one peptide, In-111-DTPA-(D)-Phe 1 -octreotide, is available commercially for oncologic imaging, many more have been examined in humans with hematological disorders, and the early results appear to be promising. Impetus generated by these results have prompted investigators to label peptides with such radionuclides as Tc-99m, I-123, F-18, Cu-64, and Y-90. This review is intended to highlight the qualities of peptides, summarize the clinical results, and address some important issues associated with radiolabeling of highly potent peptides. While doing so, various methods of radiolabeling have been described, and their strengths and weaknesses have also been discussed. (author)

A new physically-based quantification of marine isoprene and primary organic aerosol emissions

Directory of Open Access Journals (Sweden)

N. Meskhidze

2009-07-01

Full Text Available The global marine sources of organic carbon (OC are estimated here using a physically-based parameterization for the emission of marine isoprene and primary organic matter. The marine isoprene emission model incorporates new physical parameters such as light sensitivity of phytoplankton isoprene production and dynamic euphotic depth to simulate hourly marine isoprene emissions totaling 0.92 Tg C yr⁻¹. Sensitivity studies using different schemes for the euphotic zone depth and ocean phytoplankton speciation produce the upper and the lower range of marine-isoprene emissions of 0.31 to 1.09 Tg C yr⁻¹, respectively. Established relationships between sea spray fractionation of water-insoluble organic carbon (WIOC and chlorophyll-a concentration are used to estimate the total primary sources of marine sub- and super-micron OC of 2.9 and 19.4 Tg C yr⁻¹, respectively. The consistent spatial and temporal resolution of the two emission types allow us, for the first time, to explore the relative contributions of sub- and super-micron organic matter and marine isoprene-derived secondary organic aerosol (SOA to the total OC fraction of marine aerosol. Using a fixed 3% mass yield for the conversion of isoprene to SOA, our emission simulations show minor (<0.2% contribution of marine isoprene to the total marine source of OC on a global scale. However, our model calculations also indicate that over the tropical oceanic regions (30° S to 30° N, marine isoprene SOA may contribute over 30% of the total monthly-averaged sub-micron OC fraction of marine aerosol. The estimated contribution of marine isoprene SOA to hourly-averaged sub-micron marine OC emission is even higher, approaching 50% over the vast regions of the oceans during the midday hours when isoprene emissions are highest. As it is widely believed that sub-micron OC has the potential to influence the cloud droplet activation of marine aerosols, our

Measurements of aerosol fluxes to Speulder forest using a micrometeorological technique

DEFF Research Database (Denmark)

Gallagher, M.W.; Beswick, K.M.; Duyzer, J.

1997-01-01

It has often been stated that micrometeorological and throughfall measurements of dry deposition differ by an order of magnitude with the results being highly variable and difficult to interpret or reconcile. We present measurements by the eddy correlation method of sub-micron aerosol deposition...... to a forest and show that they are large, typically 1 cm s(-1) or more. We compare the measurements with literature values obtained by throughfall and related techniques. The results, rather than being irreconcilable, show a clear and consistent behaviour in deposition velocity across the aerosol size...... spectrum, despite the very different techniques involved. There would appear to be a contradiction with previously assumed model predictions of aerosol deposition Velocity to forests and rough vegetated surfaces particularly for particles in the size range 0.1-1.0 mu m where collection efficiencies appear...

Biomass burning and its effects on fine aerosol acidity, water content and nitrogen partitioning

Science.gov (United States)

Bougiatioti, Aikaterini; Nenes, Athanasios; Paraskevopoulou, Despina; Fourtziou, Luciana; Stavroulas, Iasonas; Liakakou, Eleni; Myriokefalitakis, Stelios; Daskalakis, Nikos; Weber, Rodney; Kanakidou, Maria; Gerasopoulos, Evangelos; Mihalopoulos, Nikolaos

2017-04-01

Aerosol acidity is an important property that drives the partitioning of semi-volatile species, the formation of secondary particulate matter and metal and nutrient solubility. Aerosol acidity varies considerably between aerosol types, RH, temperature, the degree of atmospheric chemical aging and may also change during transport. Among aerosol different sources, sea salt and dust have been well studied and their impact on aerosol acidity and water uptake is more or less understood. Biomass burning (BB) on the other hand, despite its significance as a source in a regional and global scale, is much less understood. Currently, there is no practical and accurate enough method, to directly measure the pH of in-situ aerosol. The combination of thermodynamic models, with targeted experimental observations can provide reliable predictions of aerosol particle water and pH, using as input the concentration of gas/aerosol species, temperature (T), and relative humidity (RH). As such an example, ISORROPIA-II (Fountoukis and Nenes, 2007) has been used for the thermodynamic analysis of measurements conducted in downtown Athens during winter 2013, in order to evaluate the effect of BB on aerosol water and acidity. Biomass burning, especially during night time, was found to contribute significantly to the increased organics concentrations, but as well to the BC component associated with wood burning, particulate nitrates, chloride, and potassium. These increased concentrations were found to impact on fine aerosol water, with Winorg having an average concentration of 11±14 μg m-3 and Worg 12±19 μg m-3 with the organic component constituting almost 38% of the total calculated submicron water. When investigating the fine aerosol acidity it was derived that aerosol was generally acidic, with average pH during strong BB influence of 2.8±0.5, value similar to the pH observed for regional aerosol influenced by important biomass burning episodes at the remote background site of

Contrasting organic aerosol particles from boreal and tropical forests during HUMPPA-COPEC-2010 and AMAZE-08 using coherent vibrational spectroscopy

Directory of Open Access Journals (Sweden)

C. J. Ebben

2011-10-01

Full Text Available We present the vibrational sum frequency generation spectra of organic particles collected in a boreal forest in Finland and a tropical forest in Brazil. These spectra are compared to those of secondary organic material produced in the Harvard Environmental Chamber. By comparing coherent vibrational spectra of a variety of terpene and olefin reference compounds, along with the secondary organic material synthesized in the environmental chamber, we show that submicron aerosol particles sampled in Southern Finland during HUMPPA-COPEC-2010 are composed to a large degree of material similar in chemical composition to synthetic α-pinene-derived material. For material collected in Brazil as part of AMAZE-08, the organic component is found to be chemically complex in the coarse mode but highly uniform in the fine mode. When combined with histogram analyses of the isoprene and monoterpene abundance recorded during the HUMPPA-COPEC-2010 and AMAZE-08 campaigns, the findings presented here indicate that if air is rich in monoterpenes, submicron-sized secondary aerosol particles that form under normal OH and O₃ concentration levels can be described in terms of their hydrocarbon content as being similar to α-pinene-derived model secondary organic aerosol particles. If the isoprene concentration dominates the chemical composition of organic compounds in forest air, then the hydrocarbon component of secondary organic material in the submicron size range is not simply well-represented by that of isoprene-derived model secondary organic aerosol particles but is more complex. Throughout the climate-relevant size range of the fine mode, however, we find that the chemical composition of the secondary organic particle material from such air is invariant with size, suggesting that the particle growth does not change the chemical composition of the hydrocarbon component of the particles in a significant way.

Relating hygroscopicity and composition of organic aerosol particulate matter

CERN Document Server

Duplissy, J; Prevot, A S H; Barmpadimos, I; Jimenez, J L; Gysel, M; Worsnop, D R; Aiken, A C; Tritscher, T; Canagaratna, M R; Collins, D R; Alfarra, M R; Metzger, A; Tomlinson, J; DeCarlo, P F; Weingartner, E; Baltensperger, U

2011-01-01

A hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopicity) of secondary organic aerosol (SOA) formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS), and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal (f(44)). m/z 44 is due mostly to the ion fragment CO(2)(+) for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfrau-joch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation b...

Real-Time Characterization of Aerosol Particle Composition above the Urban Canopy in Beijing: Insights into the Interactions between the Atmospheric Boundary Layer and Aerosol Chemistry.

Science.gov (United States)

Sun, Yele; Du, Wei; Wang, Qingqing; Zhang, Qi; Chen, Chen; Chen, Yong; Chen, Zhenyi; Fu, Pingqing; Wang, Zifa; Gao, Zhiqiu; Worsnop, Douglas R

2015-10-06

Despite extensive efforts into the characterization of air pollution during the past decade, real-time characterization of aerosol particle composition above the urban canopy in the megacity Beijing has never been performed to date. Here we conducted the first simultaneous real-time measurements of aerosol composition at two different heights at the same location in urban Beijing from December 19, 2013 to January 2, 2014. The nonrefractory submicron aerosol (NR-PM1) species were measured in situ by a high-resolution aerosol mass spectrometer at near-ground level and an aerosol chemical speciation monitor at 260 m on a 325 m meteorological tower in Beijing. Secondary aerosol showed similar temporal variations between ground level and 260 m, whereas much weaker correlations were found for the primary aerosol. The diurnal evolution of the ratios and correlations of aerosol species between 260 m and the ground level further illustrated a complex interaction between vertical mixing processes and local source emissions on aerosol chemistry in the atmospheric boundary layer. As a result, the aerosol compositions at the two heights were substantially different. Organic aerosol (OA), mainly composed of primary OA (62%), at the ground level showed a higher contribution to NR-PM1 (65%) than at 260 m (54%), whereas a higher concentration and contribution (15%) of nitrate was observed at 260 m, probably due to the favorable gas-particle partitioning under lower temperature conditions. In addition, two different boundary layer structures were observed, each interacting differently with the evolution processes of aerosol chemistry.

Quantification of the carbonaceous matter origin in submicron marine aerosol particles by dual carbon isotope analysis

Science.gov (United States)

Ceburnis, D.; Garbaras, A.; Szidat, S.; Rinaldi, M.; Fahrni, S.; Perron, N.; Wacker, L.; Leinert, S.; Remeikis, V.; Facchini, M. C.; Prevot, A. S. H.; Jennings, S. G.; O'Dowd, C. D.

2011-01-01

Dual carbon isotope analysis has been performed for the first time demonstrating a potential in organic matter apportionment between three principal sources: marine, terrestrial (non-fossil) and fossil fuel due to unique isotopic signatures. The results presented here, utilising combinations of dual carbon isotope analysis, provides a conclusive evidence of a dominant biogenic organic fraction to organic aerosol over biologically active oceans. In particular, the NE Atlantic, which is also subjected to notable anthropogenic influences via pollution transport processes, was found to contain 80% organic aerosol matter of biogenic origin directly linked to plankton emissions. The remaining carbonaceous aerosol was of fossil-fuel origin. By contrast, for polluted air advecting out from Europe into the NE Atlantic, the source apportionment is 30% marine biogenic, 40% fossil fuel, and 30% continental non-fossil fuel. The dominant marine organic aerosol source in the atmosphere has significant implications for climate change feedback processes.

Aerosol spectral optical depths and size characteristics at a coastal industriallocation in India - effect of synoptic and mesoscale weather

Directory of Open Access Journals (Sweden)

K. Niranjan

2004-06-01

Full Text Available The aerosol spectral optical depths at ten discrete channels in the visible and near IR bands, obtained from a ground-based passive multi-wavelength solar radiometer at a coastal industrial location, Visakhapatnam, on the east coast of India, are used to study the response of the aerosol optical properties and size distributions to the changes in atmospheric humidity, wind speed and direction. It is observed that during high humidity conditions, the spectral optical depths show about 30% higher growth factors, and the size distributions show the generation of a typical new mode around 0.4 microns. The surface wind speed and direction also indicate the formation of new particles when the humid marine air mass interacts with the industrial air mass. This is interpreted in terms of new particle formation and subsequent particle growth by condensation and self-coagulation. The results obtained on the surface-size segregated aerosol mass distribution from a co-located Quartz Crystal Microbalance during different humidity conditions also show a large mass increase in the sub-micron size range with an increase in atmospheric humidity, indicating new particle formation at the sub-micron size range.

Properties of submicron particles in Atmospheric Brown Clouds

Science.gov (United States)

Adushkin, V. V.; Chen, B. B.; Dubovskoi, A. N.; Friedrich, F.; Pernik, L. M.; Popel, S. I.; Weidler, P. G.

2010-05-01

The Atmospheric Brown Clouds (ABC) is an important problem of this century. Investigations of last years and satellite data show that the ABC (or brown gas, smog, fog) cover extensive territories including the whole continents and oceans. The brown gas consists of a mixture of particles of anthropogenic sulfates, nitrates, organic origin, black carbon, dust, ashes, and also natural aerosols such as sea salt and mineral dust. The brown color is a result of absorption and scattering of solar radiation by the anthropogenic black carbon, ashes, the particles of salt dust, and nitrogen dioxide. The investigation of the ABC is a fundamental problem for prevention of degradation of the environment. At present in the CIS in-situ investigations of the ABC are carried out on Lidar Station Teplokluchenka (Kyrgyz Republic). Here, we present the results of experimental investigation of submicron (nanoscale) particles originating from the ABC and the properties of the particles. Samples of dust precipitating from the ABC were obtained at the area of Lidar Station Teplokluchenka as well as scientific station of the Russian Academy of Sciences near Bishkek. The data for determination of the grain composition were obtained with the aid of the scanning electron microscopes JEOL 6460 LV and Philips XL 30 FEG. Analysis of the properties of the particles was performed by means of the X-ray diffraction using diffractometer Siemens D5000. The images of the grains were mapped. The investigation allows us to get (after the image processing) the grain composition within the dust particle size range of 60 nm to 700 μm. Distributions of nano- and microscale particles in sizes were constructed using Rozin-Rammler coordinates. Analysis of the distributions shows that the ABC contain submicron (nanoscale) particles; 2) at higher altitudes the concentration of the submicron (nanoscale) particles in the ABC is higher than at lower altitudes. The chemical compositions of the particles are shown to

Aerosol emissions from prescribed fires in the United States: A synthesis of laboratory and aircraft measurements

Science.gov (United States)

A. A. May; G. R. McMeeking; T. Lee; J. W. Taylor; J. S. Craven; I. Burling; A. P. Sullivan; S. Akagi; J. L. Collett; M. Flynn; H. Coe; S. P. Urbanski; J. H. Seinfeld; R. J. Yokelson; S. M. Kreidenweis

2014-01-01

Aerosol emissions from prescribed fires can affect air quality on regional scales. Accurate representation of these emissions in models requires information regarding the amount and composition of the emitted species. We measured a suite of submicron particulate matter species in young plumes emitted from prescribed fires (chaparral and montane ecosystems in California...

Seasonal dependence of aerosol processing in urban Philadelphia

Science.gov (United States)

Avery, A. M.; Waring, M. S.; DeCarlo, P. F.

2017-12-01

Urban aerosols pose an important threat to human health due to the conflation of emissions and concentrated population exposed. Winter and summer aerosol and trace gas measurements were taken in downtown Philadelphia in 2016. Measurements included aerosol composition and size with an Aerodyne Aerosol Mass Spectrometer (AMS), particle size distributions with an SMPS, and an aethalometer. Trace gas measurements of O3, NO, CH4, CO, and CO2 were taken concurrently. Sampling in seasonal extremes provided contrast in aerosol and trace gas composition, aerosol processing, and emission factors. Inorganic aerosol components contributed approximately 60% of the submicron aerosol mass, while summertime aerosol composition was roughly 70% organic matter. Positive Matrix Factorization (PMF) on the organic aerosol (OA) matrix revealed three factors in common in each season, including an oxygenated organic aerosol (OOA) factor with different temporal behavior in each season. In summertime, OOA varied diurnally with ozone and daytime temperature, but in the wintertime, it was anti-correlated with ozone and temperature, and instead trended with calculated liquid water, indicating a seasonally-dependent processing of organic aerosol in Philadelphia's urban environment. Due to the inorganic dominant winter aerosol, liquid water much higher (2.65 μg/m3) in winter than in summer (1.54 μg/m3). Diurnally varying concentrations of background gas phase species (CH4, CO2) were higher in winter and varied less as a result of boundary layer conditions; ozone was also higher in background in winter than summer. Winter stagnation events with low windspeed showed large buildup of trace gases CH4, CO, CO2, and NO. Traffic related aerosol was also elevated with black carbon and hydrocarbon-like OA (HOA) plumes of each at 3-5 times higher than the winter the average value for each. Winter ratios of HOA to black carbon were significantly higher in the winter than the summer due to lower

Sources and composition of submicron organic mass in marine aerosol particles

Science.gov (United States)

Frossard, Amanda A.; Russell, Lynn M.; Burrows, Susannah M.; Elliott, Scott M.; Bates, Timothy S.; Quinn, Patricia K.

2014-11-01

The sources and composition of atmospheric marine aerosol particles (aMA) have been investigated with a range of physical and chemical measurements from open-ocean research cruises. This study uses the characteristic functional group composition (from Fourier transform infrared spectroscopy) of aMA from five ocean regions to show the following: (i) The organic functional group composition of aMA that can be identified as mainly atmospheric primary marine (ocean derived) aerosol particles (aPMA) is 65 ± 12% hydroxyl, 21 ± 9% alkane, 6 ± 6% amine, and 7 ± 8% carboxylic acid functional groups. Contributions from photochemical reactions add carboxylic acid groups (15%-25%), shipping effluent in seawater and ship emissions add additional alkane groups (up to 70%), and coastal or continental emissions mix in alkane and carboxylic acid groups. (ii) The organic composition of aPMA is nearly identical to model-generated primary marine aerosol particles from bubbled seawater (gPMA, which has 55 ± 14% hydroxyl, 32 ± 14% alkane, and 13 ± 3% amine functional groups), indicating that its overall functional group composition is the direct consequence of the organic constituents of the seawater source. (iii) While the seawater organic functional group composition was nearly invariant across all three ocean regions studied and the ratio of organic carbon to sodium (OC/Na+) in the gPMA remained nearly constant over a broad range of chlorophyll a concentrations, the gPMA alkane group fraction appeared to increase with chlorophyll a concentrations (r = 0.66). gPMA from productive seawater had a larger fraction of alkane functional groups (42 ± 9%) compared to gPMA from nonproductive seawater (22 ± 10%), perhaps due to the presence of surfactants in productive seawater that stabilize the bubble film and lead to preferential drainage of the more soluble (lower alkane group fraction) organic components. gPMA has a hydroxyl group absorption peak location characteristic of

Phenomenological study of aerosol dry deposition in urban area: surface properties, turbulence and local meteorology influences

International Nuclear Information System (INIS)

Roupsard, P.

2013-01-01

Aerosol dry deposition is not much known for urban areas due to the lack of data. Knowledge on this phenomenon is necessary to understand pollutant fluxes in cities and to estimate inhabitant exposition to ionizing radiation of radioactive aerosols. A data providing could enable to enhance dry deposition models for these areas. An original experimental approach is performed to study submicron aerosol dry deposition on urban surfaces. Wind tunnel coupled to in situ experiments give results to study different physical phenomenon governing dry deposition. Dry deposition velocities are measured using aerosol tracers. These data are associated to turbulent and meteorological measured conditions. This database permits to classify the principal physical phenomenon for each experiment type. Finally, different phenomenon must be considered for chronic and acute exposition of urban surfaces to atmospheric particles. (author)

Eddy covariance measurements with high-resolution time-of-flight aerosol mass spectrometry: a new approach to chemically resolved aerosol fluxes

Directory of Open Access Journals (Sweden)

D. K. Farmer

2011-06-01

Full Text Available Although laboratory studies show that biogenic volatile organic compounds (VOCs yield substantial secondary organic aerosol (SOA, production of biogenic SOA as indicated by upward fluxes has not been conclusively observed over forests. Further, while aerosols are known to deposit to surfaces, few techniques exist to provide chemically-resolved particle deposition fluxes. To better constrain aerosol sources and sinks, we have developed a new technique to directly measure fluxes of chemically-resolved submicron aerosols using the high-resolution time-of-flight aerosol mass spectrometer (HR-AMS in a new, fast eddy covariance mode. This approach takes advantage of the instrument's ability to quantitatively identify both organic and inorganic components, including ammonium, sulphate and nitrate, at a temporal resolution of several Hz. The new approach has been successfully deployed over a temperate ponderosa pine plantation in California during the BEARPEX-2007 campaign, providing both total and chemically resolved non-refractory (NR PM₁ fluxes. Average deposition velocities for total NR-PM₁ aerosol at noon were 2.05 ± 0.04 mm s⁻¹. Using a high resolution measurement of the NH₂⁺ and NH₃⁺ fragments, we demonstrate the first eddy covariance flux measurements of particulate ammonium, which show a noon-time deposition velocity of 1.9 ± 0.7 mm s⁻¹ and are dominated by deposition of ammonium sulphate.

Dynamic-chemistry-aerosol modelling interaction: the ESCOMPTE 2001 experiment; Modelisation de l'interaction dynamique- chimie - aerosol: campagne ESCOMPTE 2001

Energy Technology Data Exchange (ETDEWEB)

Cousin, F

2004-09-01

After most pollution studies independently devoted to gases and aerosols, there now appears an urgent need to consider their interactions. In this view, an aerosol module has been implemented in the Meso-NH-C model to simulate two IOPs documented during the ESCOMPTE campaign which took place in the Marseille/Fos-Berre region in June-July 2001. First, modelled dynamic parameters (winds, temperatures, boundary layer thickness) and gaseous chemistry have been validated with measurements issued from the exhaustive ESCOMPTE database. Sensitivity analysis have also been performed using different gaseous emission inventories at various resolution. These simulations have illustrated the deep impact of both synoptic and local dynamics on observed ozone concentrations on June 24 (IOP2b) in the ESCOMPTE domain. Afterwards, the ORISAM aerosol module has been introduced into the Meso-NH-C model. Dynamics, gaseous chemistry and aerosol processes have thus been coupled on-line. The particulate pollution episode on June 24 (IOP2b) has been characterised through a satisfactory comparison, specially from sub-micron particles, between modelling and measurements at different representative stations in the domain. This study, with validation of the particulate emission inventory has also highlighted the need for future improvements, such as further characterisation of organic and inorganic aerosol species and consideration of coarse particles. Aerosol impact on gaseous chemistry has been preliminary approached in view of future development and modification to be given to the Meso-NH-C model. (author)

Nanocrystalline functional materials and nanocomposites synthesis through aerosol routes

Directory of Open Access Journals (Sweden)

Milošević Olivera B.

2003-01-01

Full Text Available This paper represents the results of the design of functional nanocrystalline powders and nanocomposites using chemical reactions in aerosols. The process involves ultrasonic aerosol formation (mist generators with the resonant frequencies of 800 kHz, 1.7 and 2.5 MHz from precursor salt solutions and control over the aerosol decomposition in a high-temperature tubular flow reactor. During decomposition, the aerosol droplets undergo evaporation/drying, precipitation and thermolysis in a single-step process. Consequently, spherical, solid, agglomerate-free submicronic particles are obtained. The particle morphology, revealed as a composite structure consisting of primary crystallites smaller than 20 nm was analysed by several methods (XRD, DSC/DTA, SEM, TEM and discussed in terms of precursor chemistry and process parameters. Following the initial attempts, a more detailed aspect of nanocrystalline particle synthesis was demonstrated for the case of nanocomposites based on ZnO-MeO (MeO=Bi Cr+, suitable for electronic applications, as well as an yttrium-aluminum base complex system, suitable for phosphorus applications. The results imply that parts of the material structure responsible for different functional behaviour appear through in situ aerosol synthesis by processes of intraparticle agglomeration, reaction and sintering in the last synthesis stage.

Radiolabeled antibody imaging

International Nuclear Information System (INIS)

Wahl, R.L.

1987-01-01

Radiolabeled antibodies, in particular monoclonal antibodies, offer the potential for the specific nuclear imaging of malignant and benign diseases in man. If this imaging potential is realized, they may also have a large role in cancer treatment. This paper reviews: (1) what monoclonal antibodies are and how they differ from polyclonal antibodies, (2) how they are produced and radiolabeled, (3) the results of preclinical and clinical trials in cancer imaging, including the utility of SPECT and antibody fragments, (4) the role of antibodies in the diagnosis of benign diseases, (5) alternate routes of antibody delivery, (6) the role of these agents in therapy, and (7) whether this technology ''revolutionizes'' the practice of nuclear radiology, or has a more limited complementary role in the imaging department

Influences of in-cloud aerosol scavenging parameterizations on aerosol concentrations and wet deposition in ECHAM5-HAM

Directory of Open Access Journals (Sweden)

B. Croft

2010-02-01

, mid-troposphere ²¹⁰Pb vertical profiles, and the geographic distribution of aerosol optical depth is found for the new diagnostic scavenging scheme compared to the prescribed scavenging fraction scheme of the standard ECHAM5-HAM. The diagnostic and prognostic schemes represent the variability of scavenged fractions particularly for submicron size aerosols, and for mixed and ice phase clouds, and are recommended in preference to the prescribed scavenging fractions method.

A review: radiolabeled synthesis of pesticides

International Nuclear Information System (INIS)

Li Juying; Han Ailiang; Wang Haiyan; Wang Wei; Ye Qingfu

2010-01-01

Isotope tracer technique has been widely applied in studies of metabolism, mode action, fate and environmental behavior of pesticides. In such studies, the key point is to obtain suitable radiolabelled compounds. However, the radiotracers, especially the labelled pesticides which are novel compounds with complex structures and longer synthesis routes, are usually unavailable from domestic and /or foreign markets. Therefore, it is essential to explore the synthesis methods of radiolabelled pesticides, which are quite different from the conventional nonradiosynthesis, and are requested to obtain higher yield. This article is a review on current status of choosing the available radionuclide and labelled position, the main synthesis methods and problems in the process of preparing radiolabelled pesticides. (authors)

Quantitative imaging with radiolabeled monoclonal antibodies

International Nuclear Information System (INIS)

Moldofsky, P.J.; Hammond, N.D.

1988-01-01

The ability to image tumor by using radiolabeled monoclonal antibody products has been widely demonstrated. The questions of safety and efficacy remain open and require further experience, but at least in some clinical situations radioimmunoimaging has provided clinically useful information. Imaging tumor with radiolabeled monoclonal and polyclonal antibodies has been widely reported, and several summaries have recently appeared. For extensive review of recent clinical imaging the reader is referred to these excellent sources. Having demonstrated the possibility of imaging tumor with radiolabeled antibody, the question now apparent is: will the imaging modality provide information new and different from the already available with established techniques in computed tomography, magnetic resonance imaging, and standard nuclear medicine?

High summertime aerosol organic functional group concentrations from marine and seabird sources at Ross Island, Antarctica, during AWARE

Directory of Open Access Journals (Sweden)

J. Liu

2018-06-01

Full Text Available Observations of the organic components of the natural aerosol are scarce in Antarctica, which limits our understanding of natural aerosols and their connection to seasonal and spatial patterns of cloud albedo in the region. From November 2015 to December 2016, the ARM West Antarctic Radiation Experiment (AWARE measured submicron aerosol properties near McMurdo Station at the southern tip of Ross Island. Submicron organic mass (OM, particle number, and cloud condensation nuclei concentrations were higher in summer than other seasons. The measurements included a range of compositions and concentrations that likely reflected both local anthropogenic emissions and natural background sources. We isolated the natural organic components by separating a natural factor and a local combustion factor. The natural OM was 150 times higher in summer than in winter. The local anthropogenic emissions were not hygroscopic and had little contribution to the CCN concentrations. Natural sources that included marine sea spray and seabird emissions contributed 56 % OM in summer but only 3 % in winter. The natural OM had high hydroxyl group fraction (55 %, 6 % alkane, and 6 % amine group mass, consistent with marine organic composition. In addition, the Fourier transform infrared (FTIR spectra showed the natural sources of organic aerosol were characterized by amide group absorption, which may be from seabird populations. Carboxylic acid group contributions were high in summer and associated with natural sources, likely forming by secondary reactions.

Recent developments in monoclonal antibody radiolabeling techniques

International Nuclear Information System (INIS)

Srivastava, S.C.; Mease, R.C.

1989-01-01

Monoclonal antibodies (MAbs) have shown the potential to serve as selective carriers of radionuclides to specific in vivo antigens. Accordingly, there has been an intense surge of research activity in an effort to develop and evaluate MAb-based radiopharmaceuticals for tumor imaging (radioimmunoscintigraphy) and therapy (radioimmunotherapy), as well as for diagnosing nonmalignant diseases. A number of problems have recently been identified, related to the MAbs themselves and to radiolabeling techniques, that comprise both the selectivity and the specificity of the in vivo distribution of radiolabeled MAbs. This paper will address some of these issues and primarily discuss recent developments in the techniques for radiolabeling monoclonal antibodies that may help resolve problems related to the poor in vivo stability of the radiolabel and may thus produce improved biodistribution. Even though many issues are identical with therapeutic radionuclides, the discussion will focus mainly on radioimmunoscintigraphic labels. 78 refs., 6 tabs

Recent developments in monoclonal antibody radiolabeling techniques

Energy Technology Data Exchange (ETDEWEB)

Srivastava, S.C.; Mease, R.C.

1989-01-01

Monoclonal antibodies (MAbs) have shown the potential to serve as selective carriers of radionuclides to specific in vivo antigens. Accordingly, there has been an intense surge of research activity in an effort to develop and evaluate MAb-based radiopharmaceuticals for tumor imaging (radioimmunoscintigraphy) and therapy (radioimmunotherapy), as well as for diagnosing nonmalignant diseases. A number of problems have recently been identified, related to the MAbs themselves and to radiolabeling techniques, that comprise both the selectivity and the specificity of the in vivo distribution of radiolabeled MAbs. This paper will address some of these issues and primarily discuss recent developments in the techniques for radiolabeling monoclonal antibodies that may help resolve problems related to the poor in vivo stability of the radiolabel and may thus produce improved biodistribution. Even though many issues are identical with therapeutic radionuclides, the discussion will focus mainly on radioimmunoscintigraphic labels. 78 refs., 6 tabs.

Ambient Aerosol in Southeast Asia: High Resolution Aerosol Mass Spectrometer Measurements Over Oil Palm (Elaeis guineensis)

Science.gov (United States)

Phillips, G.; Dimarco, C.; Misztal, P.; Nemitz, E.; Farmer, D.; Kimmel, J.; Jimenez, J.

2008-12-01

The emission of organic compounds in the troposphere is important factor in the formation of secondary organic aerosol (SOA). A very large proportion of organic material emitted globally is estimated to arise from biogenic sources, with almost half coming from tropical and sub-tropical forests. Preliminary analyses of leave cuvette emission studies suggest that oil palm (Elaeis guineensis) is a significantly larger source of isoprene than tropical forest. Much larger sources of isoprene over oil palm allied with a larger anthropogenic component of local emissions contrast greatly with the remote tropical forest environment and therefore the character of SOA formed may differ significantly. These issues, allied with the high price of palm oil on international markets leading to increased use of land for oil palm production, could give rise to rapidly changing chemical and aerosol regimes in the tropics. It is therefore important to understand the current emissions and composition of organic aerosol over all important land-uses in the tropical environment. This in turn will lead to a greater understanding of the present, and to an improvement in predictive capacity for the future system. To help address these issues, a high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) was deployed in the Sabahmas (PPB OIL) oil palm plantation near Lahad Datu, in Eastern Sabah, as part of the field component of the Aerosol Coupling in the Earth System (ACES) project, part of the UK NERC APPRAISE program. This project was allied closely with measurements made of similar chemical species and aerosol components at a forest site in the Danum Valley as part of the UK Oxidant and Particle Photochemical Processes above a Southeast Asian tropical rainforest (OP3) project. Measurements of submicron non- refractory aerosol composition are presented along with some preliminary analysis of chemically resolved aerosol fluxes made with a new eddy covariance system, based on the

Where and What Is Pristine Marine Aerosol?

Science.gov (United States)

Russell, L. M.; Frossard, A. A.; Long, M. S.; Burrows, S. M.; Elliott, S.; Bates, T. S.; Quinn, P.

2014-12-01

, 48:v-x, doi10.1080/02786826.2013.879979, 2014a. Frossard, A.A., L.M. Russell, M.S. Long, S.M. Burrows, S.M. Elliot, T.S. Bates, and P.K. Quinn, "Sources and Composition of Submicron Organic Mass in Marine Aerosol Particles," Journal of Geophysical Research - Atmospheres, submitted 2014b.

Quantification of the carbonaceous matter origin in submicron marine aerosol by 13C and 14C isotope analysis

Directory of Open Access Journals (Sweden)

M. Ramonet

2011-08-01

Full Text Available Dual carbon isotope analysis of marine aerosol samples has been performed for the first time demonstrating a potential in organic matter apportionment between three principal sources: marine, terrestrial (non-fossil and fossil fuel due to unique isotopic signatures. The results presented here, utilising combinations of dual carbon isotope analysis, provides conclusive evidence of a dominant biogenic organic fraction to organic aerosol over biologically active oceans. In particular, the NE Atlantic, which is also subjected to notable anthropogenic influences via pollution transport processes, was found to contain 80 % organic aerosol matter of biogenic origin directly linked to plankton emissions. The remaining carbonaceous aerosol was of terrestrial origin. By contrast, for polluted air advected out from Europe into the NE Atlantic, the source apportionment is 30 % marine biogenic, 40 % fossil fuel, and 30 % continental non-fossil fuel. The dominant marine organic aerosol source in the atmosphere has significant implications for climate change feedback processes.

Quantification of the carbonaceous matter origin in submicron marine aerosol by 13C and 14C isotope analysis

Science.gov (United States)

Ceburnis, D.; Garbaras, A.; Szidat, S.; Rinaldi, M.; Fahrni, S.; Perron, N.; Wacker, L.; Leinert, S.; Remeikis, V.; Facchini, M. C.; Prevot, A. S. H.; Jennings, S. G.; Ramonet, M.; O'Dowd, C. D.

2011-08-01

Dual carbon isotope analysis of marine aerosol samples has been performed for the first time demonstrating a potential in organic matter apportionment between three principal sources: marine, terrestrial (non-fossil) and fossil fuel due to unique isotopic signatures. The results presented here, utilising combinations of dual carbon isotope analysis, provides conclusive evidence of a dominant biogenic organic fraction to organic aerosol over biologically active oceans. In particular, the NE Atlantic, which is also subjected to notable anthropogenic influences via pollution transport processes, was found to contain 80 % organic aerosol matter of biogenic origin directly linked to plankton emissions. The remaining carbonaceous aerosol was of terrestrial origin. By contrast, for polluted air advected out from Europe into the NE Atlantic, the source apportionment is 30 % marine biogenic, 40 % fossil fuel, and 30 % continental non-fossil fuel. The dominant marine organic aerosol source in the atmosphere has significant implications for climate change feedback processes.

Global distribution and climate forcing of marine organic aerosol: 1. Model improvements and evaluation

Directory of Open Access Journals (Sweden)

N. Meskhidze

2011-11-01

Full Text Available Marine organic aerosol emissions have been implemented and evaluated within the National Center of Atmospheric Research (NCAR's Community Atmosphere Model (CAM5 with the Pacific Northwest National Laboratory's 7-mode Modal Aerosol Module (MAM-7. Emissions of marine primary organic aerosols (POA, phytoplankton-produced isoprene- and monoterpenes-derived secondary organic aerosols (SOA and methane sulfonate (MS⁻ are shown to affect surface concentrations of organic aerosols in remote marine regions. Global emissions of submicron marine POA is estimated to be 7.9 and 9.4 Tg yr⁻¹, for the Gantt et al. (2011 and Vignati et al. (2010 emission parameterizations, respectively. Marine sources of SOA and particulate MS⁻ (containing both sulfur and carbon atoms contribute an additional 0.2 and 5.1 Tg yr⁻¹, respectively. Widespread areas over productive waters of the Northern Atlantic, Northern Pacific, and the Southern Ocean show marine-source submicron organic aerosol surface concentrations of 100 ng m⁻³, with values up to 400 ng m⁻³ over biologically productive areas. Comparison of long-term surface observations of water insoluble organic matter (WIOM with POA concentrations from the two emission parameterizations shows that despite revealed discrepancies (often more than a factor of 2, both Gantt et al. (2011 and Vignati et al. (2010 formulations are able to capture the magnitude of marine organic aerosol concentrations, with the Gantt et al. (2011 parameterization attaining better seasonality. Model simulations show that the mixing state of the marine POA can impact the surface number concentration of cloud condensation nuclei (CCN. The largest increases (up to 20% in CCN (at a supersaturation (S of 0.2% number concentration are obtained over biologically productive ocean waters when marine organic aerosol is assumed to be externally mixed with sea-salt. Assuming

Dynamic-chemistry-aerosol modelling interaction: the ESCOMPTE 2001 experiment

International Nuclear Information System (INIS)

Cousin, F.

2004-09-01

After most pollution studies independently devoted to gases and aerosols, there now appears an urgent need to consider their interactions. In this view, an aerosol module has been implemented in the Meso-NH-C model to simulate two IOPs documented during the ESCOMPTE campaign which took place in the Marseille/Fos-Berre region in June-July 2001. First, modelled dynamic parameters (winds, temperatures, boundary layer thickness) and gaseous chemistry have been validated with measurements issued from the exhaustive ESCOMPTE database. Sensitivity analysis have also been performed using different gaseous emission inventories at various resolution. These simulations have illustrated the deep impact of both synoptic and local dynamics on observed ozone concentrations on June 24 (IOP2b) in the ESCOMPTE domain. Afterwards, the ORISAM aerosol module has been introduced into the Meso-NH-C model. Dynamics, gaseous chemistry and aerosol processes have thus been coupled on-line. The particulate pollution episode on June 24 (IOP2b) has been characterised through a satisfactory comparison, specially from sub-micron particles, between modelling and measurements at different representative stations in the domain. This study, with validation of the particulate emission inventory has also highlighted the need for future improvements, such as further characterisation of organic and inorganic aerosol species and consideration of coarse particles. Aerosol impact on gaseous chemistry has been preliminary approached in view of future development and modification to be given to the Meso-NH-C model. (author)

Ground-based aerosol characterization during the South American Biomass Burning Analysis (SAMBBA field experiment

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J. Brito

2014-11-01

Full Text Available This paper investigates the physical and chemical characteristics of aerosols at ground level at a site heavily impacted by biomass burning. The site is located near Porto Velho, Rondônia, in the southwestern part of the Brazilian Amazon rainforest, and was selected for the deployment of a large suite of instruments, among them an Aerosol Chemical Speciation Monitor. Our measurements were made during the South American Biomass Burning Analysis (SAMBBA field experiment, which consisted of a combination of aircraft and ground-based measurements over Brazil, aimed to investigate the impacts of biomass burning emissions on climate, air quality, and numerical weather prediction over South America. The campaign took place during the dry season and the transition to the wet season in September/October 2012. During most of the campaign, the site was impacted by regional biomass burning pollution (average CO mixing ratio of 0.6 ppm, occasionally superimposed by intense (up to 2 ppm of CO, freshly emitted biomass burning plumes. Aerosol number concentrations ranged from ~1000 cm−3 to peaks of up to 35 000 cm−3 (during biomass burning (BB events, corresponding to an average submicron mass mean concentrations of 13.7 μg m−3 and peak concentrations close to 100 μg m−3. Organic aerosol strongly dominated the submicron non-refractory composition, with an average concentration of 11.4 μg m−3. The inorganic species, NH4, SO4, NO3, and Cl, were observed, on average, at concentrations of 0.44, 0.34, 0.19, and 0.01 μg m−3, respectively. Equivalent black carbon (BCe ranged from 0.2 to 5.5 μg m−3, with an average concentration of 1.3 μg m−3. During BB peaks, organics accounted for over 90% of total mass (submicron non-refractory plus BCe, among the highest values described in the literature. We examined the ageing of biomass burning organic aerosol (BBOA using the changes in the H : C and O : C ratios, and found that throughout most of the

Coarse mode aerosols in the High Arctic

Science.gov (United States)

Baibakov, K.; O'Neill, N. T.; Chaubey, J. P.; Saha, A.; Duck, T. J.; Eloranta, E. W.

2014-12-01

Fine mode (submicron) aerosols in the Arctic have received a fair amount of scientific attention in terms of smoke intrusions during the polar summer and Arctic haze pollution during the polar winter. Relatively little is known about coarse mode (supermicron) aerosols, notably dust, volcanic ash and sea salt. Asian dust is a regular springtime event whose optical and radiative forcing effects have been fairly well documented at the lower latitudes over North America but rarely reported for the Arctic. Volcanic ash, whose socio-economic importance has grown dramatically since the fear of its effects on aircraft engines resulted in the virtual shutdown of European civil aviation in the spring of 2010 has rarely been reported in the Arctic in spite of the likely probability that ash from Iceland and the Aleutian Islands makes its way into the Arctic and possibly the high Arctic. Little is known about Arctic sea salt aerosols and we are not aware of any literature on the optical measurement of these aerosols. In this work we present preliminary results of the combined sunphotometry-lidar analysis at two High Arctic stations in North America: PEARL (80°N, 86°W) for 2007-2011 and Barrow (71°N,156°W) for 2011-2014. The multi-years datasets were analyzed to single out potential coarse mode incursions and study their optical characteristics. In particular, CIMEL sunphotometers provided coarse mode optical depths as well as information on particle size and refractive index. Lidar measurements from High Spectral Resolution lidars (AHSRL at PEARL and NSHSRL at Barrow) yielded vertically resolved aerosol profiles and gave an indication of particle shape and size from the depolarization ratio and color ratio profiles. Additionally, we employed supplementary analyses of HYSPLIT backtrajectories, OMI aerosol index, and NAAPS (Navy Aerosol Analysis and Prediction System) outputs to study the spatial context of given events.

Atmospheric residence times of continental aerosols

International Nuclear Information System (INIS)

Balkanski, Y.J.

1991-01-01

The global atmospheric distributions of Rn-222 are simulated with a three-dimensional model of atmospheric transport based on the meteorology of the NASA Goddard Institute for Space Studies (GISS) general circulation model. The short-lived radioactive gas Rn-222 (half-life = 3.8d) is emitted almost exclusively from land, at a relatively uniform rate; hence it is an excellent tracer of continental influences. Lead-210 is produced by decay of Rn-222 and immediately condenses to preexisting aerosol surfaces. It provides an excellent measure of aerosol residence times in the atmosphere because its source is accurately defined by the Rn-222 distribution. Results from the three-dimensional model are compared to measurements of Rn-222 and Pb-210 atmospheric concentrations to evaluate model's long-range transport over oceanic regions and to study the deposition mechanisms of atmospheric aerosols. Model results for Rn-222 are used to examine the long-range transport of continental air over two selected oceanic regions, the subantarctic Indian Ocean and the North Pacific. It is shown that the fast transport of air from southern Africa causes substantial continental pollution at southern mid-latitudes, a region usually regarded as pristine. Air over the North Pacific is heavily impacted by continental influences year round, but the altitude at which the transport occurs varies seasonally. Observations of aerosols at island sites, which are commonly used as diagnostics of continental influences, may be misleading because they do not account for influences at high altitude and because aerosols are efficiently scavenged by deposition during transport. The study of Pb-210 focuses on defining the residence times of submicron aerosols in the troposphere. Scavenging in wet convective updrafts is found to provide the dominant sink on a global scale

Research of the arid aerosol carrying out with a help of a set of sodars

International Nuclear Information System (INIS)

Valery, K; Igor, G

2008-01-01

Study of spatial and vertical distribution of vertical wind velocity was carried out in the 'Har-Gzyr 2007' field program in the 'Black Sands' region, Russia, with the help of four sodars. Continuous (about half an hour) and stable anabatic motions of the air were revealed for altitudes 10m to 800m over the area of some square kilometres. The measured vertical speed reached 2m/s. Permanent and quick transfer of sub-micron aerosol particles from the surface layer to the troposphere can be explained by this phenomenon. The scheme is proposed to design a mass balance equation to calculate aerosol concentration in the upper layers of the ABL

Overview of aerosol properties associated with air masses sampled by the ATR-42 during the EUCAARI campaign (2008

Directory of Open Access Journals (Sweden)

S. Crumeyrolle

2013-05-01

Full Text Available Within the frame of the European Aerosol Cloud Climate and Air Quality Interactions (EUCAARI project, the Météo-France aircraft ATR-42 performed 22 research flights over central Europe and the North Sea during the intensive observation period in May 2008. For the campaign, the ATR-42 was equipped to study the aerosol physical, chemical, hygroscopic and optical properties, as well as cloud microphysics. For the 22 research flights, retroplume analyses along the flight tracks were performed with FLEXPART in order to classify air masses into five sectors of origin, allowing for a qualitative evaluation of emission influence on the respective air parcel. This study shows that the extensive aerosol parameters (aerosol mass and number concentrations show vertical decreasing gradients and in some air masses maximum mass concentrations (mainly organics in an intermediate layer (1–3 km. The observed mass concentrations (in the boundary layer (BL: between 10 and 30 μg m−3; lower free troposphere (LFT: 0.8 and 14 μg m−3 are high especially in comparison with the 2015 European norms for PM2.5 (25 μg m−3 and with previous airborne studies performed over England (Morgan et al., 2009; McMeeking et al., 2012. Particle number size distributions show a larger fraction of particles in the accumulation size range in the LFT compared to BL. The chemical composition of submicron aerosol particles is dominated by organics in the BL, while ammonium sulphate dominates the submicron aerosols in the LFT, especially in the aerosol particles originated from north-eastern Europe (~ 80%, also experiencing nucleation events along the transport. As a consequence, first the particle CCN acting ability, shown by the CCN/CN ratio, and second the average values of the scattering cross sections of optically active particles (i.e. scattering coefficient divided by the optical active particle concentration are increased in the LFT compared to BL.

Effects of Ocean Ecosystem on Marine Aerosol-Cloud Interaction

Directory of Open Access Journals (Sweden)

Nicholas Meskhidze

2010-01-01

Full Text Available Using satellite data for the surface ocean, aerosol optical depth (AOD, and cloud microphysical parameters, we show that statistically significant positive correlations exist between ocean ecosystem productivity, the abundance of submicron aerosols, and cloud microphysical properties over different parts of the remote oceans. The correlation coefficient for remotely sensed surface chlorophyll a concentration ([Chl-a] and liquid cloud effective radii over productive areas of the oceans varies between −0.2 and −0.6. Special attention is given to identifying (and addressing problems from correlation analysis used in the previous studies that can lead to erroneous conclusions. A new approach (using the difference between retrieved AOD and predicted sea salt aerosol optical depth, AODdiff is developed to explore causal links between ocean physical and biological systems and the abundance of cloud condensation nuclei (CCN in the remote marine atmosphere. We have found that over multiple time periods, 550 nm AODdiff (sensitive to accumulation mode aerosol, which is the prime contributor to CCN correlates well with [Chl-a] over the productive waters of the Southern Ocean. Since [Chl-a] can be used as a proxy of ocean biological productivity, our analysis demonstrates the role of ocean ecology in contributing CCN, thus shaping the microphysical properties of low-level marine clouds.

Preparation and biodistribution of radiolabeled fullerene C60 nanocrystals

International Nuclear Information System (INIS)

Nikolic, Nadezda; Vranjes-Duric, Sanja; Jankovic, Drina; Dokic, Divna; Mirkovic, Marija; Bibic, Natasa; Trajkovic, Vladimir

2009-01-01

The present study describes for the first time a procedure for the radiolabeling of fullerene (C 60 ) nanocrystals (nanoC 60 ) with Na 125 I, as well as the biodistribution of radiolabeled nanoC 60 ( 125 I-nanoC 60 ). The solvent exchange method with tetrahydrofuran was used to make colloidal water suspensions of radiolabeled nanoC 60 particles. The radiolabeling procedure with the addition of Na 125 I to tetrahydrofuran during dissolution of C 60 gave a higher radiochemical yield of radiolabeled nanoC 60 particles in comparison to the second option, in which Na 125 I was added after C 60 was dissolved. Using photon correlation spectroscopy and transmission electron microscopy, 125 I-nanoC 60 particles were found to have a crystalline structure and a mean diameter of 200-250 nm. The 125 I-nanoC 60 had a particularly high affinity for human serum albumin, displaying 95% binding efficiency after 1 h. Biodistribution studies of 125 I-nanoC 60 in rats indicated significant differences in tissue accumulation of 125 I-nanoC 60 and the radioactive tracer Na 125 I. The higher accumulation of radiolabeled nanoC 60 was observed in liver and spleen, while accumulation in thyroid, stomach, lungs and intestines was significantly lower in comparison to Na 125 I. In addition to being useful for testing the biological distribution of nanoC 60 , the described radiolabeling procedure might have possible applications in cancer radiotherapy.

Experimental determination of submicron aerosol dry deposition velocity onto rural canopies: influence of aerosol size, of micro meteorological parameters and of the substrate

International Nuclear Information System (INIS)

Damay, P.

2010-04-01

To evaluate the impact of accidental or chronic pollutant releases on ecosystems, we must study the dry deposition of aerosols in rural areas. The lack of experimental data on the dry deposition velocity of particle sizes below 1 μm over rural environments leads to uncertainties regarding models and differences between them, which exceed one order of magnitude. The aim of this study is to develop a method, especially using an Electrical Low Pressure Impactor (Outdoor ELPIDEKATI) to determine aerosol dry deposition velocities (Vd) over rural areas through experimental measurements. This method is based on eddy covariance flux calculation and spectral analysis correction. Dry deposition velocities were obtained for atmospheric aerosols sizing from 7 nm to 2 μm, in the South-West of France on a flat terrain under varied meteorological conditions and varied substrates (maize, grass and earth). Vd was analysed as a function of the particle diameters, and the impact of micro meteorological parameters was studied. (author)

An in situ cell to study phase transitions in individual aerosol particles on a substrate using scanning transmission x-ray microspectroscopy

International Nuclear Information System (INIS)

Huthwelker, T.; Zelenay, V.; Birrer, M.; Krepelova, A.; Raabe, J.; Ammann, M.; Tzvetkov, G.; Vernooij, M. G. C.

2010-01-01

A new in situ cell to study phase transitions and chemical processes on individual aerosol particles in the x-ray transmission microscope at the PolLux beamline of the Swiss light source has been built. The cell is machined from stainless steel and aluminum components and is designed to be used in the standard mount of the microscope without need of complicated rearrangements of the microscope. The cell consists of two parts, a back part which contains connections for the gas supply, heating, cooling devices, and temperature measurement. The second part is a removable clip, which hosts the sample. This clip can be easily exchanged and brought into a sampling unit for aerosol particles. Currently, the cell can be operated at temperatures ranging from -40 to +50 deg. C. The function of the cell is demonstrated using two systems of submicron size: inorganic sodium bromide aerosols and soot originating from a diesel passenger car. For the sodium bromide we demonstrate how phase transitions can be studied in these systems and that O1s spectra from aqueous sodium bromide solution can be taken from submicron sized particles. For the case of soot, we demonstrate that the uptake of water onto individual soot particles can be studied.

New characteristics of submicron aerosols and factor analysis of combined organic and inorganic aerosol mass spectra during winter in Beijing

Science.gov (United States)

Zhang, J. K.; Ji, D. S.; Liu, Z. R.; Hu, B.; Wang, L. L.; Huang, X. J.; Wang, Y. S.

2015-07-01

In recent years, an increasing amount of attention has been paid to heavy haze pollution in Beijing, China. In addition to Beijing's population of approximately 20 million and its 5 million vehicles, nearby cities and provinces are host to hundreds of heavily polluting industries. In this study, a comparison between observations in January 2013 and January 2014 showed that non-refractory PM1 (NR-PM1) pollution was weaker in January 2014, which was primarily caused by variations in meteorological conditions. For the first time, positive matrix factorization (PMF) was applied to the merged high-resolution mass spectra of organic and inorganic aerosols from aerosol mass spectrometer measurements in Beijing, and the sources and evolution of NR-PM1 in January 2014 were investigated. The two factors, NO3-OA1 and NO3-OA2, were primarily composed of ammonium nitrate, and each showed a different degree of oxidation and diurnal variation. The organic fraction of SO4-OA showed the highest degree of oxidation of all PMF factors. The hydrocarbon-like organic aerosol (OA) and cooking OA factors contained negligible amounts of inorganic species. The coal combustion OA factor contained a high contribution from chloride in its mass spectrum. The NR-PM1 composition showed significant variations in January 2014, in which the contribution of nitrate clearly increased during heavy pollution events. The most effective way to control fine particle pollution in Beijing is through joint prevention and control measures at the regional level, rather than a focus on an individual city, especially for severe haze events.

Ambient Aerosols in the Southern Hemisphere on Ascension Island during the LASIC Campaign: Biomass Burning Season versus Near Pristine Background Conditions

Science.gov (United States)

Aiken, A. C.; Springston, S. R.; Watson, T. B.; Sedlacek, A. J., III; Zuidema, P.; Adebiyi, A. A.; Uin, J.; Kuang, C.; Flynn, C. J.

2017-12-01

Ascension Island is located 8 degrees South of the Equator and 15 degrees West Longitude in the middle of the South Atlantic Ocean, at least 1000 miles from any major shoreline and closest to the continent of Africa. While low Southern Hemisphere background aerosol and trace gas measurements are observed most of the year, that picture changes during the South African Biomass Burning (BB) season. BB emissions are a large source of carbon to the atmosphere via particles and gas phase species and with a potential rise in drought and extreme events in the future, these numbers are expected to increase. From approximately June-October every year, the plume of South African BB emissions, the largest BB source in the world, are advected West and are known to impact both the boundary layer and free troposphere at Ascension Island (Zuidema et al., 2016). During the U.S. DOE ARM field campaign, Layered Atlantic Smoke Interactions with Clouds (LASIC), aerosol and trace gas measurements were collected continuously from June 2016 through October 2017 over a 1.5 year period. Two BB seasons are contrasted with the near pristine background conditions during the campaign from the ARM Aerosol Mobile Facility 1 (AMF1) and Mobile Aerosol Observing System (MAOS). Numerous direct in situ aerosol and trace gas measurements are presented, e.g. black carbon (BC), carbon monoxide (CO), PM1 and PM10 aerosol absorption and scattering, submicron non-refractory chemical composition (Organics, Sulfate, Nitrate, Ammonium, Chloride), etc. Aerosol and trace gas signatures are investigated along with backtrajectories to identify sources. Carbonaceous aerosols emitted with gas-phase CO are used to determine particulate emission ratios along with intrinsic and extrinsic aerosol properties. BC mass concentrations reach 1 µg m-3 during multiday plumes and exceed 25% of the total aerosol submicron mass concentration. Organic Aerosol (OA) to BC Ratios of 2.4 in the plume are much higher than previously

Submicron particulate organic matter in the urban atmosphere: a new method for real-time measurement, molecular-level characterization and source apportionment

Science.gov (United States)

Müller, Markus; Eichler, Philipp; D'Anna, Barbara; Tan, Wen; Wisthaler, Armin

2017-04-01

We used a novel chemical analytical method for measuring submicron particulate organic matter in the atmosphere of three European cities (Innsbruck, Lyon, Valencia). Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) was used in combination with the "chemical analysis of aerosol online" (CHARON) inlet for detecting particulate organic compounds on-line (i.e. without filter pre-collection), in real-time (1-min time resolution), at ng m-3 concentrations, with molecular-level resolution (i.e. obtaining molecular weight and elemental composition information). The CHARON-PTR-ToF-MS system monitored molecular tracers associated with different particle sources including levoglucosan from biomass combustion, PAHs from vehicular traffic, nicotine from cigarette smoking, and monoterpene oxidation products secondarily formed from biogenic emissions. The tracer information was used for interpreting positive matrix factorization (PMF) data which allowed us to apportion the sources of submicron particulate organic matter in the different urban environments. This work was funded through the PIMMS ITN, which was supported by the European Commission's 7th Framework Programme under grant agreement number 287382.

Development of Radiolabeled compounds using reactor-produced radionuclides

International Nuclear Information System (INIS)

Choi, Sun Ju; Park, K. B.; Park, S. H.

2007-06-01

To establish a robust technology for radiopharmaceutical development, we focused on the configuration of fundamental development of radiolabeled compounds for radioimmunotherapy and drug delivery as well as the development of bifunctional chelating agents and radiolabeling methods for the radiopharmaceuticals with highly specific activity to deliver sufficient number of radionuclides to the target site. In this project, we aim to improve the quality of life and the public welfare by fostering the medical application of radioisotopes for the effective treatment of malignant diseases and by developing efficient radiolabeling methods of specific bio-active materials with radioisotopes and new candidates for radiopharmaceutical application. We have established the procedure for the preparation of radiolabeled antibody and biotin with radioisotopes such as 166 Ho, 131 I, 90 Y and 111 In for tumour targeting. In the future, these technologies will be applicable to development of radioimmunotherapeutic drug. The combination treatment of radioisotope with anti-cancer agents or chemotherapeutic agents may produce a synergistic static effects in the tumour and this synergism would be exerted via gene level through the activation of a cell death pathway. The combination therapy may be very beneficial for cancer treatment and this can overcome not only the hazards of unnecessary exposure to high radiation level during therapy, but also the tendency for drug resistance caused by chemotherapy. To develop new drug delivery system suitable for CT imaging agent, a chitosan derivative and radiolabed Folate-targeted polymer with 131 I were synthesized. We also carried out the development of DTPA derivatives for CT imaging agent, radiolabeled precursor, and established a highly efficient radiolabeling methodology with lanthanide nuclide. In order to develop neuroreceptor targeting compounds, we synthesized WAY-100635 compound and 99m Tc(CO) 3 precursor from Chrysamine G derivatives

Chemical, physical, and optical evolution of biomass burning aerosols: a case study

Science.gov (United States)

Adler, G.; Flores, J. M.; Abo Riziq, A.; Borrmann, S.; Rudich, Y.

2011-02-01

In-situ chemical composition measurements of ambient aerosols have been used for characterizing the evolution of submicron aerosols from a large anthropogenic biomass burning (BB) event in Israel. A high resolution Time of Flight Aerosol Mass Spectrometer (HR-RES-TOF-AMS) was used to follow the chemical evolution of BB aerosols during a night-long, extensive nationwide wood burning event and during the following day. While these types of extensive BB events are not common in this region, burning of agricultural waste is a common practice. The aging process of the BB aerosols was followed through their chemical, physical and optical properties. Mass spectrometric analysis of the aerosol organic component showed that aerosol aging is characterized by shifting from less oxidized fresh BB aerosols to more oxidized aerosols. Evidence for aerosol aging during the day following the BB event was indicated by an increase in the organic mass, its oxidation state, the total aerosol concentration, and a shift in the modal particle diameter. The effective broadband refractive index (EBRI) was derived using a white light optical particle counter (WELAS). The average EBRI for a mixed population of aerosols dominated by open fires was m = 1.53(±0.03) + 0.07i(±0.03), during the smoldering phase of the fires we found the EBRI to be m = 1.54(±0.01) + 0.04i(±0.01) compared to m = 1.49(±0.01) + 0.02i(±0.01) of the aged aerosols during the following day. This change indicates a decrease in the overall aerosol absorption and scattering. Elevated levels of particulate Polycyclic Aromatic Hydrocarbons (PAHs) were detected during the entire event, which suggest possible implications for human health during such extensive event.

Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice

Directory of Open Access Journals (Sweden)

R. S. Humphries

2016-02-01

Full Text Available Better characterisation of aerosol processes in pristine, natural environments, such as Antarctica, have recently been shown to lead to the largest reduction in uncertainties in our understanding of radiative forcing. Our understanding of aerosols in the Antarctic region is currently based on measurements that are often limited to boundary layer air masses at spatially sparse coastal and continental research stations, with only a handful of studies in the vast sea-ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the icebreaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3 concentrations exhibited a five-fold increase moving across the polar front, with mean polar cell concentrations of 1130 cm−3 – higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low-pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air masses quickly from the free troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea-ice boundary layer air masses travelled equatorward into the low-albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei which, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and their transport pathways described here, could help reduce the discrepancy currently present between

Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice

Science.gov (United States)

Humphries, R. S.; Klekociuk, A. R.; Schofield, R.; Keywood, M.; Ward, J.; Wilson, S. R.

2016-02-01

Better characterisation of aerosol processes in pristine, natural environments, such as Antarctica, have recently been shown to lead to the largest reduction in uncertainties in our understanding of radiative forcing. Our understanding of aerosols in the Antarctic region is currently based on measurements that are often limited to boundary layer air masses at spatially sparse coastal and continental research stations, with only a handful of studies in the vast sea-ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the icebreaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3) concentrations exhibited a five-fold increase moving across the polar front, with mean polar cell concentrations of 1130 cm-3 - higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low-pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air masses quickly from the free troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea-ice boundary layer air masses travelled equatorward into the low-albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei which, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and their transport pathways described here, could help reduce the discrepancy currently present between simulations and observations of

Targeting of human glioma xenografts in vivo utilizing radiolabeled antibodies

International Nuclear Information System (INIS)

Williams, J.A.; Wessels, B.W.; Wharam, M.D.; Order, S.E.; Wanek, P.M.; Poggenburg, J.K.; Klein, J.L.

1990-01-01

Radiolabeled antibodies provide a potential basis for selective radiotherapy of human gliomas. We have measured tumor targeting by radiolabeled monoclonal and polyclonal antibodies directed against neuroectodermal and tumor-associated antigens in nude mice bearing human glioma xenografts. Monoclonal P96.5, a mouse IgG2a immunoglobulin, defines an epitope of a human melanoma cell surface protein, and specifically binds the U-251 human glioma as measured by immunoperoxidase histochemistry. 111In-radiolabeled P96.5 specifically targets the U-251 human glioma xenograft and yields 87.0 microCuries (microCi) of tumor activity per gram per 100 microCi injected activity compared to 4.5 microCi following administration of radiolabeled irrelevant monoclonal antibody. Calculations of targeting ratios demonstrate deposited dose to be 11.6 times greater with radiolabeled P96.5 administration compared to irrelevant monoclonal antibody. The proportion of tumor dose found in normal organs is less than 10%, further supporting specific targeting of the human glioma xenograft by this antibody. Monoclonal antibody ZME018, which defines a second melanoma-associated antigen, and polyclonal rabbit antiferritin, which defines a tumor-associated antigen, demonstrate positive immunoperoxidase staining of the tumor, but comparatively decreased targeting. When compared to the 111In-radiolabeled antibody, 90Y-radiolabeled P96.5 demonstrates comparable tumor targeting and percentages of tumor dose found in normal organs. To test the therapeutic potential of 90Y-radiolabeled P96.5, tumors and normal sites were implanted with miniature thermoluminescent dosimeters (TLD). Seven days following administration of 100 microCi 90Y-radiolabeled P96.5, average absorbed doses of 3770, 980, 353, and 274 cGy were observed in tumor, liver, contralateral control site, and total body, respectively

Creation of device for monitoring of inhalation exposure doses in 'Ukryttia' object conditions considering submicron aerosols

International Nuclear Information System (INIS)

Melenevskij, A.Eh.; Kravchuk, T.A.; Ushakov, I.A.

2003-01-01

In the conditions of air enriched with Short-Lived Aerosols (SLA), the examinations of created device ASMA sampler were conducted in order to define its ability of educing rougher fractions from aspirated aerosol compositions. It is shown that in airflow velocity intervals from 100 to 140 m/s aerodynamic diameter of an effluent fraction varies from 0.9 to 0.7 microns. The algorithm of measurement result processing of aspirated filter strata activity is described.Using the numerical modeling, the efficiency of offered procedure of relative measurements is demonstrated

Micromagnetic simulations of submicron cobalt dots

International Nuclear Information System (INIS)

Parker, G. J.; Cerjan, C.

2000-01-01

Numerical simulations of submicron Co extruded elliptical dots were performed to illustrate the relative importance of different physical parameters on the switching behavior in the easy direction. Shape, size, magnetic moment magnitude, and the magnitude and distribution of the crystalline anisotropicity were varied. The simulation represents magnetostatic, exchange, and crystalline anisotropicity fields on a structured mesh using finite difference techniques. The smooth boundary of the dots is accurately represented by use of the embedded curve boundary method. Agreement with experimental hysteresis measurements of submicron dot arrays is obtained when an appropriate angular distribution of the grain anisotropicity axes is invoked. (c) 2000 American Institute of Physics

Investigating organic aerosol loading in the remote marine environment

Directory of Open Access Journals (Sweden)

K. Lapina

2011-09-01

Full Text Available Aerosol loading in the marine environment is investigated using aerosol composition measurements from several research ship campaigns (ICEALOT, MAP, RHaMBLe, VOCALS and OOMPH, observations of total AOD column from satellite (MODIS and ship-based instruments (Maritime Aerosol Network, MAN, and a global chemical transport model (GEOS-Chem. This work represents the most comprehensive evaluation of oceanic OM emission inventories to date, by employing aerosol composition measurements obtained from campaigns with wide spatial and temporal coverage. The model underestimates AOD over the remote ocean on average by 0.02 (21 %, compared to satellite observations, but provides an unbiased simulation of ground-based Maritime Aerosol Network (MAN observations. Comparison with cruise data demonstrates that the GEOS-Chem simulation of marine sulfate, with the mean observed values ranging between 0.22 μg m⁻³ and 1.34 μg m⁻³, is generally unbiased, however surface organic matter (OM concentrations, with the mean observed concentrations between 0.07 μg m⁻³ and 0.77 μg m⁻³, are underestimated by a factor of 2–5 for the standard model run. Addition of a sub-micron marine OM source of approximately 9 TgC yr⁻¹ brings the model into agreement with the ship-based measurements, however this additional OM source does not explain the model underestimate of marine AOD. The model underestimate of marine AOD is therefore likely the result of a combination of satellite retrieval bias and a missing marine aerosol source (which exhibits a different spatial pattern than existing aerosol in the model.

AIRWAY RETENTION OF MATERIALS OF DIFFERENT SOLUBILITY FOLLOWING LOCAL INTRABRONCHIAL DEPOSITION IN DOGS

Science.gov (United States)

We used a gamma camera to monitor the retention and clearance of radiolabeled human serum albumin (HSA), a water-soluble material with molecular weight of 66,000 Daltons, and radiolabeled sulfur colloid (SC), an insoluble submicron (0.22 microm) particle, following localized depo...

Radiolabelled monoclonal antibodies: magic bullets for colorectal carcinoma

International Nuclear Information System (INIS)

Slade, Linda

1997-01-01

Radiolabelled monoclonal antibodies (MoAbs) have been heralded as highly specific detection agents for many types of tumours. However, because of the many problems that have been associated with the use of these agents, their development and successes did not meet expectations. This paper discusses the use of radiolabelled MoAbs in the diagnosis and staging of colorectal cancer, the type of antibodies and radionuclides investigated over the past thirty years, and the advantages and disadvantages of each. An attempt is made to define the role of radioimmunoscintigraphy (RIS) in the investigation and management of patients with colorectal cancer. It appears that this technique can improve tumour detection, especially when used in conjunction with other imaging modalities. High sensitivities and specificities have been found using radio-labelled MoAbs for investigation of colorectal carcinoma. However, the author estimates there are a number of areas that require further research and improvement before naming radiolabelled MoAbs as 'magic bullets' for colorectal cancer. 8 refs., 3 tabs

Radiolabeled antibodies and RGD-peptides for the treatment of ovarian cancer.

NARCIS (Netherlands)

Janssen, M.L.H.

2004-01-01

In this thesis, preclinical studies on new treatment modalities for ovarian cancer are descibed, applying radiolabeled antibodies and radiolabeled RGD-peptides. In chapter 2 a study is described comparing the therapeutic efficacy of the antibody HMFG1 radiolabeled with several beta-emitting

Preparation of radiolabeled bioactive asbestos fibers

Energy Technology Data Exchange (ETDEWEB)

Tewson, T J; Francsechini, M P; Scheule, R K; Holian, A [Texas Univ., Houston, TX (USA). Health Science Center

1991-01-01

We have developed an efficient procedure to radiolabel asbestos fibers while retaining the bioactivity of the fibers. The fibers are labeled with {sup 68}Ge. The {sup 68}Ge decays into {sup 68}Ga, which then can be detected by its characteristic positron emission. Both chrysotile and crocidolite asbestos, a serpentine and an amphibole, respectively, were radiolabeled successfully. Mild reaction conditions and short reaction times were found under which {similar to}90% of the added {sup 68}Ge and {sup 68}Ga bound to the fibers. The radiolabel was retained even after washing the fibers extensively with physiologic buffers. The effects of the labeling on the bioactivity of the fibers were evaluated in an in vitro assay using guinea pig alveolar macrophages as a target cell. Labeled chrysotile fibers were found to retain >95% of their ability to stimulate these cells. The labeling procedure described in this study should be useful in preparing labeled fibers to investigate both in vitro and in vivo phenomena. (author).

Microfluidic radiolabeling of biomolecules with PET radiometals

International Nuclear Information System (INIS)

Zeng Dexing; Desai, Amit V.; Ranganathan, David; Wheeler, Tobias D.; Kenis, Paul J.A.; Reichert, David E.

2013-01-01

Introduction: A robust, versatile and compact microreactor has been designed, fabricated and tested for the labeling of bifunctional chelate conjugated biomolecules (BFC-BM) with PET radiometals. Methods: The developed microreactor was used to radiolabel a chelate, either 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) or 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) that had been conjugated to cyclo(Arg-Gly-Asp-DPhe-Lys) peptide, with both 64 Cu and 68 Ga respectively. The microreactor radiolabeling conditions were optimized by varying temperature, concentration and residence time. Results: Direct comparisons between the microreactor approach and conventional methods showed improved labeling yields and increased reproducibility with the microreactor under identical labeling conditions, due to enhanced mass and heat transfer at the microscale. More importantly, over 90% radiolabeling yields (incorporation of radiometal) were achieved with a 1:1 stoichiometry of bifunctional chelate biomolecule conjugate (BFC-BM) to radiometal in the microreactor, which potentially obviates extensive chromatographic purification that is typically required to remove the large excess of unlabeled biomolecule in radioligands prepared using conventional methods. Moreover, higher yields for radiolabeling of DOTA-functionalized BSA protein (Bovine Serum Albumin) were observed with 64 Cu/ 68 Ga using the microreactor, which demonstrates the ability to label both small and large molecules. Conclusions: A robust, reliable, compact microreactor capable of chelating radiometals with common chelates has been developed and validated. Based on our radiolabeling results, the reported microfluidic approach overall outperforms conventional radiosynthetic methods, and is a promising technology for the radiometal labeling of commonly utilized BFC-BM in aqueous solutions.

Clouds and aerosols in Puerto Rico ─ a new evaluation

Directory of Open Access Journals (Sweden)

U. Dusek

2008-03-01

Full Text Available The influence of aerosols, both natural and anthropogenic, remains a major area of uncertainty when predicting the properties and behaviour of clouds and their influence on climate. In an attempt to better understand warm cloud formation in a tropical marine environment, a period of intensive measurements took place in December 2004 in Puerto Rico, using some of the latest developments in online instrumentation such as aerosol mass spectrometers, cloud condensation nuclei counters and a hygroscopicity tandem differential mobility analyser. Simultaneous online measurements of aerosol size distributions, composition, hygroscopicity and optical properties were made near the lighthouse of Cape San Juan in the north-eastern corner of the island and at the top of East Peak mountain (1040 m a.s.l., the two sites separated by 17 km. Additional measurements of the cloud droplet residual and interstitial aerosol properties were made at the mountain site, accompanied by measurements of cloud droplet size distributions, liquid water content and the chemical composition of cloud and rain water samples. Both aerosol composition and cloud properties were found to be sensitive to wind sector. Air from the east-northeast (ENE was mostly free of anthropogenic influences, the submicron fraction being mainly composed of non-sea salt sulphate, while that from the east-southeast (ESE was found to be moderately influenced by populated islands upwind, adding smaller (<100 nm, externally mixed, carbonaceous particles to the aerosol that increased the number concentrations by over a factor of 3. This change in composition was also accompanied with a reduction in the measured hygroscopicity and fractional cloud activation potential of the aerosol. At the mountain site, the average cloud droplet concentrations increased from 193 to 519 cm−3, median volume diameter decreased from 20 to 14 μm and the liquid water content increased from 0.24 to 0.31 g m−3 when the winds

Complementary online aerosol mass spectrometry and offline FT-IR spectroscopy measurements: Prospects and challenges for the analysis of anthropogenic aerosol particle emissions

Science.gov (United States)

Faber, Peter; Drewnick, Frank; Bierl, Reinhard; Borrmann, Stephan

2017-10-01

The aerosol mass spectrometer (AMS) is well established in investigating highly time-resolved dynamics of submicron aerosol chemical composition including organic aerosol (OA). However, interpretation of mass spectra on molecular level is limited due to strong fragmentation of organic substances and potential reactions inside the AMS ion chamber. Results from complementary filter-based FT-IR absorption measurements were used to explain features in high-resolution AMS mass spectra of different types of OA (e.g. cooking OA, cigarette smoking OA, wood burning OA). Using this approach some AMS fragment ions were validated in this study as appropriate and rather specific markers for a certain class of organic compounds for all particle types under investigation. These markers can therefore be used to get deeper insights in the chemical composition of OA based on AMS mass spectra in upcoming studies. However, the specificity of other fragment ions such as C2H4O2+ (m/z 60.02114) remains ambiguous. In such cases, complementary FT-IR measurements allow the interpretation of highly time-resolved AMS mass spectra at the level of molecular functional groups. Furthermore, this study discusses the challenges in reducing inorganic interferences (e.g. from water and ammonium salts) in FT-IR spectra of atmospheric aerosols to decrease spectral uncertainties for better comparisons and, thus, to get more robust results.

Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea-ice

Science.gov (United States)

Humphries, R. S.; Klekociuk, A. R.; Schofield, R.; Keywood, M.; Ward, J.; Wilson, S. R.

2015-10-01

The effect of aerosols on clouds and their radiative properties is one of the largest uncertainties in our understanding of radiative forcing. A recent study has concluded that better characterisation of pristine, natural aerosol processes leads to the largest reduction in these uncertainties. Antarctica, being far from anthropogenic activities, is an ideal location for the study of natural aerosol processes. Aerosol measurements in Antarctica are often limited to boundary layer air-masses at spatially sparse coastal and continental research stations, with only a handful of studies in the sea ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the ice-breaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3) concentrations exhibited a five-fold increase moving across the Polar Front, with mean Polar Cell concentrations of 1130 cm-3 - higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air-masses quickly from the free-troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea ice boundary layer air-masses travelled equator-ward into the low albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei where, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and

Cavity cooling of an optically levitated submicron particle

Science.gov (United States)

Kiesel, Nikolai; Blaser, Florian; Delić, Uroš; Grass, David; Kaltenbaek, Rainer; Aspelmeyer, Markus

2013-01-01

The coupling of a levitated submicron particle and an optical cavity field promises access to a unique parameter regime both for macroscopic quantum experiments and for high-precision force sensing. We report a demonstration of such controlled interactions by cavity cooling the center-of-mass motion of an optically trapped submicron particle. This paves the way for a light–matter interface that can enable room-temperature quantum experiments with mesoscopic mechanical systems. PMID:23940352

System for exposing animals to radiolabeled diesel exhaust

International Nuclear Information System (INIS)

Lopez, J.A.; Wolf, I.; Wolff, R.K.; Sun, J.D.; Mokler, B.V.

1981-01-01

One approach to determining the deposition and fate of inhaled diesel particles is the conduct of inhalation exposure studies with radiolabeled diesel fuel. A system was designed, constructed and tested for the simultaneous exposure of animals to radiolabeled diesel exhaust and collection of large quantities of radiolabeled diesel exhaust particles from a single cylinder diesel engine. The system performance was characterized and evaluated over a range of operating conditions: 0 to 1800 watts of engine load, 1000 to 2500 rpm and dilution air rates of 1:2 and 1:10. The exposure system met required design and operating criteria for safety, portability, space and flexibility

Role of organic aerosols in CCN activation and closure over a rural background site in Western Ghats, India

Science.gov (United States)

Singla, V.; Mukherjee, S.; Safai, P. D.; Meena, G. S.; Dani, K. K.; Pandithurai, G.

2017-06-01

The cloud condensation nuclei (CCN) closure study was performed to exemplify the effect of aerosol chemical composition on the CCN activity of aerosols at Mahabaleshwar, a high altitude background site in the Western Ghats, India. For this, collocated aerosol, CCN, Elemental Carbon (EC), Organic Carbon (OC), sub-micron aerosol chemical speciation for the period from 3rd June to 19th June 2015 was used. The chemical composition of non-refractory particulate matter (theory on the basis of measured aerosol particle number size distribution, size independent NR-PM1 chemical composition and calculated hygroscopicity. The CCN closure study was evaluated for 3 scenarios, B-I (all soluble inorganics), B-IO (all soluble organics and inorganics) and B-IOOA (all soluble inorganic and soluble oxygenated organic aerosol, OOA). OOA component was derived from the positive matrix factorization (PMF) analysis of organic aerosol mass spectra. Considering the bulk composition as internal mixture, CCN closure study was underestimated by 16-39% for B-I and overestimated by 47-62% for B-IO. The CCN closure result was appreciably improved for B-IOOA where the knowledge of OOA fraction was introduced and uncertainty reduced to within 8-10%.

Enhancement of the aerosol direct radiative effect by semi-volatile aerosol components: airborne measurements in North-Western Europe

Directory of Open Access Journals (Sweden)

W. T. Morgan

2010-09-01

Full Text Available A case study of atmospheric aerosol measurements exploring the impact of the vertical distribution of aerosol chemical composition upon the radiative budget in North-Western Europe is presented. Sub-micron aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS on both an airborne platform and a ground-based site at Cabauw in the Netherlands. The examined period in May 2008 was characterised by enhanced pollution loadings in North-Western Europe and was dominated by ammonium nitrate and Organic Matter (OM. Both ammonium nitrate and OM were observed to increase with altitude in the atmospheric boundary layer. This is primarily attributed to partitioning of semi-volatile gas phase species to the particle phase at reduced temperature and enhanced relative humidity. Increased ammonium nitrate concentrations in particular were found to strongly increase the ambient scattering potential of the aerosol burden, which was a consequence of the large amount of associated water as well as the enhanced mass. During particularly polluted conditions, increases in aerosol optical depth of 50–100% were estimated to occur due to the observed increase in secondary aerosol mass and associated water uptake. Furthermore, the single scattering albedo was also shown to increase with height in the boundary layer. These enhancements combined to increase the negative direct aerosol radiative forcing by close to a factor of two at the median percentile level. Such increases have major ramifications for regional climate predictions as semi-volatile components are often not included in aerosol models.

The results presented here provide an ideal opportunity to test regional and global representations of both the aerosol vertical distribution and subsequent impacts in North-Western Europe. North-Western Europe can be viewed as an analogue for the possible future air quality over other polluted regions of the Northern Hemisphere, where

Nasopharyngeal deposition and retention of an insoluble aerosol in rats

Energy Technology Data Exchange (ETDEWEB)

Calamosca, M.; Pagano, P. (ENEA, Bologna (Italy))

1991-01-01

Forty-four female Sprague-Dawley rats were exposed, nose-only, to a 0.67 {mu}m CMAD radiolabelled Carnauba wax aerosol. The animals were sacrificed immediately after a given exposure to determine the rapid nasopharyngeal clearance rate. Clearance times were 12, 20, 30 and 44 min and 1, 2, 4, 8, 190, 357, and 549 h. Aerosol amounts remaining in the nasopharynx as a function of time were fitted to a two term exponential decay equation of the form: R(t)=Aexp(-K{sub 1}t) +Bexp(-K{sub 2}t) where the constants were found to be A=0.156{+-}0.007, K{sub 1}=3.2{+-}0.3 h{sup -1}, B=0.011{+-} 0.003, and K{sub 2}=0.008{+-} 0.010h{sup -1}. The relative deposition in the nasal region was found to be 20{+-}5%. (author).

Recent advances in understanding secondary organic aerosol: Implications for global climate forcing: Advances in Secondary Organic Aerosol

Energy Technology Data Exchange (ETDEWEB)

Shrivastava, Manish [Pacific Northwest National Laboratory, Richland Washington USA; Cappa, Christopher D. [Department of Civil and Environmental Engineering, University of California, Davis California USA; Fan, Jiwen [Pacific Northwest National Laboratory, Richland Washington USA; Goldstein, Allen H. [Department of Environmental Science, Policy and Management and Department of Civil and Environmental Engineering, University of California, Berkeley California USA; Guenther, Alex B. [Department of Earth System Science, University of California, Irvine California USA; Jimenez, Jose L. [Cooperative Institute for Research in Environmental Sciences and Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder Colorado USA; Kuang, Chongai [Brookhaven National Laboratory, Upton New York USA; Laskin, Alexander [Pacific Northwest National Laboratory, Richland Washington USA; Martin, Scot T. [School of Engineering and Applied Sciences and Department of Earth and Planetary Sciences, Harvard University, Cambridge Massachusetts USA; Ng, Nga Lee [School of Chemical and Biomolecular Engineering and School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta Georgia USA; Petaja, Tuukka [Department of Physics, University of Helsinki, Helsinki Finland; Pierce, Jeffrey R. [Department of Atmospheric Science, Colorado State University, Fort Collins Colorado USA; Rasch, Philip J. [Pacific Northwest National Laboratory, Richland Washington USA; Roldin, Pontus [Department of Physics, Lund University, Lund Sweden; Seinfeld, John H. [Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena California USA; Shilling, John [Pacific Northwest National Laboratory, Richland Washington USA; Smith, James N. [Department of Earth System Science, University of California, Irvine California USA; Thornton, Joel A. [Department of Atmospheric Sciences, University of Washington, Seattle Washington USA; Volkamer, Rainer [Cooperative Institute for Research in Environmental Sciences and Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder Colorado USA; Wang, Jian [Brookhaven National Laboratory, Upton New York USA; Worsnop, Douglas R. [Aerodyne Research, Inc., Billerica Massachusetts USA; Zaveri, Rahul A. [Pacific Northwest National Laboratory, Richland Washington USA; Zelenyuk, Alla [Pacific Northwest National Laboratory, Richland Washington USA; Zhang, Qi [Department of Environmental Toxicology, University of California, Davis California USA

2017-06-01

Anthropogenic emissions and land-use changes have modified atmospheric aerosol concentrations and size distributions over time. Understanding pre-industrial conditions and changes in organic aerosol due to anthropogenic activities is important because these features 1) influence estimates of aerosol radiative forcing and 2) can confound estimates of the historical response of climate to increases in greenhouse gases (e.g. the ‘climate sensitivity’). Secondary organic aerosol (SOA), formed in the atmosphere by oxidation of organic gases, represents a major fraction of global submicron-sized atmospheric organic aerosol. Over the past decade, significant advances in understanding SOA properties and formation mechanisms have occurred through a combination of laboratory and field measurements, yet current climate models typically do not comprehensively include all important SOA-relevant processes. Therefore, major gaps exist at present between current measurement-based knowledge on the one hand and model implementation of organic aerosols on the other. The critical review herein summarizes some of the important developments in understanding SOA formation that could potentially have large impacts on our understanding of aerosol radiative forcing and climate. We highlight the importance of some recently discovered processes and properties that influence the growth of SOA particles to sizes relevant for clouds and radiative forcing, including: formation of extremely low-volatility organics in the gas-phase; isoprene epoxydiols (IEPOX) multi-phase chemistry; particle-phase oligomerization; and physical properties such as viscosity. In addition, this review also highlights some of the important processes that involve interactions between natural biogenic emissions and anthropogenic emissions, such as the role of sulfate and oxides of nitrogen (NOx) on SOA formation from biogenic volatile organic compounds. Studies that relate the observed evolution of organic aerosol

Influence of biomass burning on mixing state of sub-micron aerosol particles in the North China Plain

Science.gov (United States)

Kecorius, Simonas; Ma, Nan; Teich, Monique; van Pinxteren, Dominik; Zhang, Shenglan; Gröβ, Johannes; Spindler, Gerald; Müller, Konrad; Iinuma, Yoshiteru; Hu, Min; Herrmann, Hartmut; Wiedensohler, Alfred

2017-09-01

Particulate emissions from crop residue burning decrease the air quality as well as influence aerosol radiative properties on a regional scale. The North China Plain (NCP) is known for the large scale biomass burning (BB) of field residues, which often results in heavy haze pollution episodes across the region. We have been able to capture a unique BB episode during the international CAREBeijing-NCP intensive field campaign in Wangdu in the NCP (38.6°N, 115.2°E) from June to July 2014. It was found that aerosol particles originating from this BB event showed a significantly different mixing state compared with clean and non-BB pollution episodes. BB originated particles showed a narrower probability density function (PDF) of shrink factor (SF). And the maximum was found at shrink factor of 0.6, which is higher than in other episodes. The non-volatile particle number fraction during the BB episode decreased to 3% and was the lowest measured value compared to all other predefined episodes. To evaluate the influence of particle mixing state on aerosol single scattering albedo (SSA), SSA at different RHs was simulated using the measured aerosol physical-chemical properties. The differences between the calculated SSA for biomass burning, clean and pollution episodes are significant, meaning that the variation of SSA in different pollution conditions needs to be considered in the evaluation of aerosol direct radiative effects in the NCP. And the calculated SSA was found to be quite sensitive on the mixing state of BC, especially at low-RH condition. The simulated SSA was also compared with the measured values. For all the three predefined episodes, the measured SSA are very close to the calculated ones with assumed mixing states of homogeneously internal and core-shell internal mixing, indicating that both of the conception models are appropriate for the calculation of ambient SSA in the NCP.

Isolating and identifying atmospheric ice-nucleating aerosols: a new technique

Science.gov (United States)

Kreidenweis, S. M.; Chen, Y.; Rogers, D. C.; DeMott, P. J.

Laboratory studies examined two key aspects of the performance of a continuous-flow diffusion chamber (CFD) instrument that detects ice nuclei (IN) concentrations in air samples: separating IN from non-IN, and collecting IN aerosols to determine chemical composition. In the first study, submicron AgI IN particles were mixed in a sample stream with submicron non-IN salt particles, and the sample stream was processed in the CFD at -19°C and 23% supersaturation with respect to ice. Examination of the residual particles from crystals nucleated in the CFD confirmed that only AgI particles served as IN in the mixed stream. The second study applied this technique to separate and analyze IN and non-IN particles in a natural air sample. Energy-dispersive X-ray analyses (EDS) of the elemental composition of selected particles from the IN and non-IN fractions in ambient air showed chemical differences: Si and Ca were present in both, but S, Fe and K were also detected in the non-IN fraction.

Microfluidic radiolabeling of biomolecules with PET radiometals.

Science.gov (United States)

Zeng, Dexing; Desai, Amit V; Ranganathan, David; Wheeler, Tobias D; Kenis, Paul J A; Reichert, David E

2013-01-01

A robust, versatile and compact microreactor has been designed, fabricated and tested for the labeling of bifunctional chelate conjugated biomolecules (BFC-BM) with PET radiometals. The developed microreactor was used to radiolabel a chelate, either 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) or 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) that had been conjugated to cyclo(Arg-Gly-Asp-DPhe-Lys) peptide, with both ⁶⁴Cu and ⁶⁸Ga respectively. The microreactor radiolabeling conditions were optimized by varying temperature, concentration and residence time. Direct comparisons between the microreactor approach and conventional methods showed improved labeling yields and increased reproducibility with the microreactor under identical labeling conditions, due to enhanced mass and heat transfer at the microscale. More importantly, over 90% radiolabeling yields (incorporation of radiometal) were achieved with a 1:1 stoichiometry of bifunctional chelate biomolecule conjugate (BFC-BM) to radiometal in the microreactor, which potentially obviates extensive chromatographic purification that is typically required to remove the large excess of unlabeled biomolecule in radioligands prepared using conventional methods. Moreover, higher yields for radiolabeling of DOTA-functionalized BSA protein (Bovine Serum Albumin) were observed with ⁶⁴Cu/⁶⁸Ga using the microreactor, which demonstrates the ability to label both small and large molecules. A robust, reliable, compact microreactor capable of chelating radiometals with common chelates has been developed and validated. Based on our radiolabeling results, the reported microfluidic approach overall outperforms conventional radiosynthetic methods, and is a promising technology for the radiometal labeling of commonly utilized BFC-BM in aqueous solutions. Copyright © 2013 Elsevier Inc. All rights reserved.

Stable Carbon Fractionation In Size Segregated Aerosol Particles Produced By Controlled Biomass Burning

Science.gov (United States)

Masalaite, Agne; Garbaras, Andrius; Garbariene, Inga; Ceburnis, Darius; Martuzevicius, Dainius; Puida, Egidijus; Kvietkus, Kestutis; Remeikis, Vidmantas

2014-05-01

Biomass burning is the largest source of primary fine fraction carbonaceous particles and the second largest source of trace gases in the global atmosphere with a strong effect not only on the regional scale but also in areas distant from the source . Many studies have often assumed no significant carbon isotope fractionation occurring between black carbon and the original vegetation during combustion. However, other studies suggested that stable carbon isotope ratios of char or BC may not reliably reflect carbon isotopic signatures of the source vegetation. Overall, the apparently conflicting results throughout the literature regarding the observed fractionation suggest that combustion conditions may be responsible for the observed effects. The purpose of the present study was to gather more quantitative information on carbonaceous aerosols produced in controlled biomass burning, thereby having a potential impact on interpreting ambient atmospheric observations. Seven different biomass fuel types were burned under controlled conditions to determine the effect of the biomass type on the emitted particulate matter mass and stable carbon isotope composition of bulk and size segregated particles. Size segregated aerosol particles were collected using the total suspended particle (TSP) sampler and a micro-orifice uniform deposit impactor (MOUDI). The results demonstrated that particle emissions were dominated by the submicron particles in all biomass types. However, significant differences in emissions of submicron particles and their dominant sizes were found between different biomass fuels. The largest negative fractionation was obtained for the wood pellet fuel type while the largest positive isotopic fractionation was observed during the buckwheat shells combustion. The carbon isotope composition of MOUDI samples compared very well with isotope composition of TSP samples indicating consistency of the results. The measurements of the stable carbon isotope ratio in

A program to operate the TSI electrical aerosol analyser using an IBM-PC microcomputer - technical background

International Nuclear Information System (INIS)

Horton, K.D.; Mitchell, J.P.; Snelling, K.W.

1988-02-01

A program has been written to enable the TSI Electrical Aerosol Analyser (EAA model 3030) to be operated using an IBM-PC microcomputer. Although much of the program is based on the software supplied by TSI Inc to collect and process data from the EAA, it incorporates numerous improvements including the option to operate the EAA automatically via a TSI Differential Mobility Particle Sizer interface. When compiled, the program enables the data reduction which takes into account the significant cross-channel sensitivity of the EAA, to be performed in about 30 seconds making it possible to use the EAA to monitor rapid changes in the behaviour of sub-micron aerosol particles. (author)

Evolution of Asian aerosols during transpacific transport in INTEX-B

Energy Technology Data Exchange (ETDEWEB)

Dunlea, E. J.; DeCarlo, Peter; Aiken, Allison; Kimmel, Joel; Peltier, R. E.; Weber, R. J.; Tomlinson, Jason M.; Collins, Donald R.; Shinozuka, Yohei; McNaughton, C. S.; Howell, S. G.; Clarke, A. D.; Emmons, L.; Apel, Eric; Pfister, G. G.; van Donkelaar, A.; Martin, R. V.; Millet, D. B.; Heald, C. L.; Jimenez, J. L.

2009-10-01

Measurements of aerosol composition were made with an Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) on board the NSF/NCAR C-130 aircraft as part of the Intercontinental Chemical Transport Experiment Phase B 5 (INTEX-B) field campaign over the Eastern Pacific Ocean. The HR-ToF-AMS measurements of non-refractory submicron aerosol mass are shown to compare well with other aerosol instrumentation in the INTEX-B field study. Two case studies are described for pollution layers transported across the Pacific from the Asian continent, intercepted 3–4 days and 7–10 days downwind of Asia, respectively. Aerosol chemistry is shown to 10 be a robust tracer for air masses originating in Asia, specifically the presence of sulfate dominated aerosol is a distinguishing feature of Asian pollution layers that have been transported to the Eastern Pacific. We examine the time scales of processing for sulfate and organic aerosol in the atmosphere and show that our observations confirm a conceptual model for transpacific transport from Asia proposed by Brock et al. (2004). 15 Our observations of both sulfate and organic aerosol in aged Asian pollution layers are consistent with fast formation near the Asian continent, followed by washout during lofting and subsequent transformation during transport across the Pacific. Our observations are the first atmospheric measurements to indicate that although secondary organic aerosol (SOA) formation from pollution happens on the timescale of one day, 20 the oxidation of organic aerosol continues at longer timescales in the atmosphere. Comparisons with chemical transport models of data from the entire campaign reveal an under-prediction of SOA mass in the MOZART model, but much smaller discrepancies with the GEOS-Chem model than found in previous studies over the Western Pacific. No evidence is found to support a previous hypothesis for significant secondary 25 organic aerosol formation in the free troposphere.

Measurement and analysis of the concentration and size distribution of aerosols in a copper mine

International Nuclear Information System (INIS)

Li Dehong; Zhuo Weihai; Huang Gang; Su Xu; Sun Quanfu

2008-01-01

Objective: To explore the general characteristics of the concentration and size distribution of aerosols in a mine. Methods: In different areas of a non-uranium mine, the particle number and mass concentration of aerosols were surveyed with a condensation particle counter and a personal aerosol monitor, respectively, and the size distribution of aerosols larger than 1 μm in size was estimated according to the size- selective measurements of mass concentrations. The size distribution of submicron aerosols was evaluated based on the method of screen diffusion battery (SOB), and the measurements were performed in both inside and outside of a control room. Results: The mass concentration of inhaled particles (PM10) was averaged to be 0.42 mg/m 3 in the whole mine, and it varied with different working areas and significantly affected with human activities. In the mine, particles lager than 1 μm in size widely distributed, while the particles less than 5 nm in size were seldom observed. Conclusions: The characteristics of aerosol significantly change with different working areas, human activities and Antilation condition in mine. The dose contribution from inhaled radioactive particles larger than 1 μm in size should be considered in mine. (authors)

On the sub-micron aerosol size distribution in a coastal-rural site at El Arenosillo Station (SW – Spain

Directory of Open Access Journals (Sweden)

M. Sorribas

2011-11-01

Full Text Available This study focuses on the analysis of the sub-micron aerosol characteristics at El Arenosillo Station, a rural and coastal environment in South-western Spain between 1 August 2004 and 31 July 2006 (594 days. The mean total concentration (N_T was 8660 cm⁻³ and the mean concentrations in the nucleation (N_NUC, Aitken (N_AIT and accumulation (N_ACC particle size ranges were 2830 cm⁻³, 4110 cm⁻³ and 1720 cm⁻³, respectively. Median size distribution was characterised by a single-modal fit, with a geometric diameter, median number concentration and geometric standard deviation of 60 nm, 5390 cm⁻³ and 2.31, respectively. Characterisation of primary emissions, secondary particle formation, changes to meteorology and long-term transport has been necessary to understand the seasonal and annual variability of the total and modal particle concentration. Number concentrations exhibited a diurnal pattern with maximum concentrations around noon. This was governed by the concentrations of the nucleation and Aitken modes during the warm seasons and only by the nucleation mode during the cold seasons. Similar monthly mean total concentrations were observed throughout the year due to a clear inverse variation between the monthly mean N_NUC and N_ACC. It was related to the impact of desert dust and continental air masses on the monthly mean particle levels. These air masses were associated with high values of N_ACC which suppressed the new particle formation (decreasing N_NUC. Each day was classified according to a land breeze flow or a synoptic pattern influence. The median size distribution for desert dust and continental aerosol was dominated by the Aitken and accumulation modes, and marine air masses were dominated by the nucleation and Aitken modes. Particles

Investigations into the penetration and pressure drop of HEPA filter media during loading with submicron particle aerosols at high concentrations

International Nuclear Information System (INIS)

Leibold, H; Wilhelm, J.G.

1991-01-01

High Efficiency Particulate Air (HEPA) filters are typically employed in particle removal and retention within the air cleaning systems of clean rooms in the pharmaceutical, nuclear and semiconductor industries for dust concentrations of some μg/m 3 . Their extremely high removal efficiencies for submicron particles make them attractive candidates in complying with increasingly lower emission limits for industrial processes that involve dust concentrations of up to several g/m 3 . Cost-effective operation under such conditions requires the filter units to be recleanable. The recleanability of HEPA filter media depends not only on the operating conditions during the cleaning process but also on the filtration conditions during particle loading. The structure and location of the particles captured by the glass fiber matrix greatly affect the degree to which they can be subsequently dislodged and removed from the filter medium. Changes in filtration efficiency with service time for various particle diameters in the critical submicron size range, as well as the effects of filtration velocity on the increase in pressure drop, are important criteria with regard to recleaning HEPA filter units. Of special significance for the recleanability of HEPA filter media is knowledge of how operating conditions affect dust cake formation. (author)

Biodistribution of radiolabeled lymphocytes

International Nuclear Information System (INIS)

Fawwaz, R.A.; Oluwole, S.; Wang, T.S.; Kuromoto, N.; Iga, C.; Hardy, M.A.; Alderson, P.O.

1985-01-01

Factors that might affect the biodistribution and clinical utility of radiolabeled lymphocytes were evaluated in experimental animals. Indium-111 (In-111) labeled lymphocytes obtained from peripheral blood, lymph node, or spleen were found in significant amounts in the lymphoid tissues of Lewis rats as early as 3 hours after infusion. A progressive increase in nodal activity with concomitant fall of activity in other organs followed, indicating active recirculation of the lymphocytes. In vitro irradiation of the In-111 labeled lymphocytes resulted in no detectable lymphocyte recirculation and/or reduced localization in lymphoid tissue. Splenectomized animals and those sensitized to an organ allograft before cell infusion showed increased activity in their bone marrow. These results suggest that the source of the injected cells, cell irradiation dose level and host sensitization should be considered when radiolabeled lymphocytes are being prepared for use in clinical diagnosis and therapy

Positron Emission Tomography Imaging Using Radiolabeled Inorganic Nanomaterials

Science.gov (United States)

Sun, Xiaolian; Cai, Weibo; Chen, Xiaoyuan

2015-01-01

CONSPECTUS Positron emission tomography (PET) is a radionuclide imaging technology that plays an important role in preclinical and clinical research. With administration of a small amount of radiotracer, PET imaging can provide a noninvasive, highly sensitive, and quantitative readout of its organ/tissue targeting efficiency and pharmacokinetics. Various radiotracers have been designed to target specific molecular events. Compared with antibodies, proteins, peptides, and other biologically relevant molecules, nanoparticles represent a new frontier in molecular imaging probe design, enabling the attachment of different imaging modalities, targeting ligands, and therapeutic payloads in a single vector. We introduce the radiolabeled nanoparticle platforms that we and others have developed. Due to the fundamental differences in the various nanoparticles and radioisotopes, most radiolabeling methods are designed case-by-case. We focus on some general rules about selecting appropriate isotopes for given types of nanoparticles, as well as adjusting the labeling strategies according to specific applications. We classified these radiolabeling methods into four categories: (1) complexation reaction of radiometal ions with chelators via coordination chemistry; (2) direct bombardment of nanoparticles via hadronic projectiles; (3) synthesis of nanoparticles using a mixture of radioactive and nonradioactive precursors; (4) chelator-free postsynthetic radiolabeling. Method 1 is generally applicable to different nanomaterials as long as the surface chemistry is well-designed. However, the addition of chelators brings concerns of possible changes to the physicochemical properties of nanomaterials and detachment of the radiometal. Methods 2 and 3 have improved radiochemical stability. The applications are, however, limited by the possible damage to the nanocomponent caused by the proton beams (method 2) and harsh synthetic conditions (method 3). Method 4 is still in its infancy

Atmospheric Residence Times of Continental Aerosols.

Science.gov (United States)

Balkanski, Yves Jacques

The global atmospheric distributions of ^{222}Rn and ^{210 }Pb are simulated with a three-dimensional model of atmospheric transport based on the meteorology of the NASA GISS^1>=neral circulation model. The short-lived radioactive gas ^ {222}Rn (half-life = 3.8d) is emitted almost exclusively from land, at a relatively uniform rate; hence it is an excellent tracer of continental influences. Lead -210 is produced by decay of ^{222} Rn and immediately condenses to preexisting aerosol surfaces. It provides an excellent measure of aerosol residence times in the atmosphere because its source is accurately defined by the ^{222} Rn distribution. Results from the three-dimensional model are compared to measurements of ^ {222}Rn and ^{210 }Pb atmospheric concentrations to evaluate model's long-range transport over oceanic regions and to study the deposition mechanisms of atmospheric aerosols. Model results for ^{222} Rn are used to examine the long-range transport of continental air over two selected oceanic regions, the subantartic Indian Ocean and the North Pacific. It is shown that fast transport of air from southern Africa causes substantial continental pollution at southern mid-latitudes, a region usually regarded as pristine. Air over the North Pacific is heavily impacted by continental influences year round, but the altitude at which the transport occurs varies seasonally. Observations of aerosols at island sites, which are commonly used as diagnostics of continental influences, may be misleading because they do not account for influences at high altitude and because aerosols are efficiently scavenged by deposition during transport. The study of ^{210}Pb focuses on defining the residence times of submicron aerosols in the troposphere. Scavenging in wet convective updrafts is found to provide the dominant sink on a global scale. The globally averaged residence time for ^{210 }Pb-containing aerosols in the troposphere is 7 days. The average increase in residence time

The Pasadena Aerosol Characterization Observatory (PACO: chemical and physical analysis of the Western Los Angeles basin aerosol

Directory of Open Access Journals (Sweden)

S. P. Hersey

2011-08-01

Full Text Available The Pasadena Aerosol Characterization Observatory (PACO represents the first major aerosol characterization experiment centered in the Western/Central Los Angeles Basin. The sampling site, located on the campus of the California Institute of Technology in Pasadena, was positioned to sample a continuous afternoon influx of transported urban aerosol with a photochemical age of 1–2 h and generally free from major local contributions. Sampling spanned 5 months during the summer of 2009, which were broken into 3 regimes on the basis of distinct meteorological conditions. Regime I was characterized by a series of low pressure systems, resulting in high humidity and rainy periods with clean conditions. Regime II typified early summer meteorology, with significant morning marine layers and warm, sunny afternoons. Regime III was characterized by hot, dry conditions with little marine layer influence. Regardless of regime, organic aerosol (OA is the most significant constituent of nonrefractory submicron Los Angeles aerosol (42, 43, and 55 % of total submicron mass in regimes I, II, and III, respectively. The overall oxidation state remains relatively constant on timescales of days to weeks (O:C = 0.44 ± 0.08, 0.55 ± 0.05, and 0.48 ± 0.08 during regimes I, II, and III, respectively, with no difference in O:C between morning and afternoon periods. Periods characterized by significant morning marine layer influence followed by photochemically favorable afternoons displayed significantly higher aerosol mass and O:C ratio, suggesting that aqueous processes may be important in the generation of secondary aerosol and oxidized organic aerosol (OOA in Los Angeles. Online analysis of water soluble organic carbon (WSOC indicates that water soluble organic mass (WSOM reaches maxima near 14:00–15:00 local time (LT, but the percentage of AMS organic mass contributed by WSOM remains relatively constant throughout the day. Sulfate and nitrate reside predominantly

Radiolabelled RGD peptides for imaging and therapy

Energy Technology Data Exchange (ETDEWEB)

Gaertner, F.C.; Schwaiger, M.; Beer, A.J. [Technische Universitaet Muenchen, Department of Nuclear Medicine, Klinikum rechts der Isar, Munich (Germany); Kessler, H. [Technische Universitaet Muenchen, Institute for Advanced Study and Center of Integrated Protein Science, Department of Chemistry, Garching (Germany); King Abdulaziz University, Chemistry Department, Faculty of Science, Jeddah (Saudi Arabia); Wester, H.-J. [Institute for Pharmaceutical Radiochemistry, Garching (Germany)

2012-02-15

Imaging of angiogenesis has become increasingly important with the rising use of targeted antiangiogenic therapies like bevacizumab (Avastin). Non-invasive assessment of angiogenic activity is in this respect interesting, e.g. for response assessment of such targeted antiangiogenic therapies. One promising approach of angiogenesis imaging is imaging of specific molecular markers of the angiogenic cascade like the integrin {alpha}{sub v}{beta}{sub 3}. For molecular imaging of integrin expression, the use of radiolabelled peptides is still the only approach that has been successfully translated into the clinic. In this review we will summarize the current data on imaging of {alpha}{sub v}{beta}{sub 3} expression using radiolabelled RGD peptides with a focus on tracers already in clinical use. A perspective will be presented on the future clinical use of radiolabelled RGD peptides including an outlook on potential applications for radionuclide therapy. (orig.)

A Novel Submicron Emulsion System Loaded with Doxorubicin Overcome Multi-Drug Resistance in MCF-7/ADR Cells.

Science.gov (United States)

Zhou, W P; Hua, H Y; Sun, P C; Zhao, Y X

2015-01-01

The purpose of the present study was to develop the Solutol HS15-based doxorubicin submicron emulsion with good stability and overcoming multi-drug resistance. In this study, we prepared doxorubicin submicron emulsion, and examined the stability after autoclaving, the in vitro cytotoxic activity, the intracellular accumulation and apoptpsis of doxorubicin submicron emulsion in MCF-7/ADR cells. The physicochemical properties of doxorubicin submicron emulsion were not significantly affected after autoclaving. The doxorubicin submicron emulsion significantly increased the intracellular accumulation of doxorubicin submicron emulsion and enhanced cytotoxic activity and apoptotic effects of doxorubicin. These results may be correlated to doxorubicin submicron emulsion inhibitory effects on efflux pumps through the progressive release of intracellular free Solutol HS15 from doxorubicin submicron emulsion. Furthermore, these in vitro results suggest that the Solutol HS15-based submicron emulsion may be a potentially useful drug delivery system to circumvent multi-drug resistance of tumor cells.

Composition and method for stabilizing radiolabelled compounds using thiocarbonylated diethylenetriamines

International Nuclear Information System (INIS)

Tzodikov, N.R.

1984-01-01

Radiolabelled compounds, such as amino acids, nucleosides, vitamins and drugs, are stabilised against radiolytic decomposition by adding a solution of a thiocarbonylated diethylenetriamine to a solution of the radiolabelled compound. (author)

GENERATION, TRANSPORT AND DEPOSITION OF TUNGSTEN-OXIDE AEROSOLS AT 1000 C IN FLOWING AIR-STEAM MIXTURES.

Energy Technology Data Exchange (ETDEWEB)

GREENE,G.A.; FINFROCK,C.C.

2001-10-01

Experiments were conducted to measure the rates of oxidation and vaporization of pure tungsten rods in flowing air, steam and air-steam mixtures in laminar flow. Also measured were the downstream transport of tungsten-oxide condensation aerosols and their region of deposition, including plateout in the superheated flow tube, rainout in the condenser and ambient discharge which was collected on an array of sub-micron aerosol filters. The nominal conditions of the tests, with the exception of the first two tests, were tungsten temperatures of 1000 C, gas mixture temperatures of 200 C and wall temperatures of 150 C to 200 C. It was observed that the tungsten oxidation rates were greatest in all air and least in all steam, generally decreasing non-linearly with increasing steam mole fraction. The tungsten oxidation rates in all air were more than five times greater than the tungsten oxidation rates in all steam. The tungsten vaporization rate was zero in all air and increased with increasing steam mole fraction. The vaporization rate became maximum at a steam mole fraction of 0.85 and decreased thereafter as the steam mole fraction was increased to unity. The tungsten-oxide was transported downstream as condensation aerosols, initially flowing upwards from the tungsten rod through an 18-inch long, one-inch diameter quartz tube, around a 3.5-inch radius, 90{sup o} bend and laterally through a 24-inch horizontal run. The entire length of the quartz glass flow path was heated by electrical resistance clamshell heaters whose temperatures were individually controlled and measured. The tungsten-oxide plateout in the quartz tube was collected, nearly all of which was deposited at the end of the heated zone near the entrance to the condenser which was cold. The tungsten-oxide which rained out in the condenser as the steam condensed was collected with the condensate and weighed after being dried. The aerosol smoke which escaped the condenser was collected on the sub-micron

Aerosol measurements on a metal waste volume reduction study

International Nuclear Information System (INIS)

Sehmel, G.A.; Schwendiman, L.C.; Lloyd, F.A.; Hodgson, W.H.

1975-09-01

Particulates generated in an experiment in which stainless steel scrap was melted by the exothermic reaction between silicon and oxygen were sampled. The objective of the sampling was to characterize the particles in the off-gas stream and to determine the total weight of particles airborne. The objective was only partially achieved since the mass of airborne particles was so large that full-flow sampling was possible only for a short period. The particles were analyzed and found to contain Si, Al, Na, and Ba, with Si representing the greatest component. The aerosol was characterized by being typically condensed fume with primary particles of submicron sizes

Imaging thrombus with radiolabelled monoclonal antibody to platelets

Energy Technology Data Exchange (ETDEWEB)

Peters, A.M.; Lavender, J.P.; Needham, S.G.; Loutfi, I.; Snook, D.; Epenetos, A.A.; Lumley, P.; Keery, R.J.; Hogg, N.

1986-12-13

A study was conducted evaluating a method of imaging thrombus with platelets radiolabelled with a /sup 111/In labelled monoclonal antibody, P256, directed to the platelet surface glycoprotein complex IIb/IIIa. when the number of receptors occupied by P256 was less than 3% of the total available on the platelet surface, platelet function was undisturbed. P256 was radiolabelled with /sup 111/In using diethylenetriaminepenta-acetic acid, which achieved a specific activity of 185 MBq (5 mCi)/mg. No impairment of immunoreactivity was detected at this specific activity. Platelets were labelled with radiolabelled monoclonal antibody in vitro in two patients at a receptor occupancy of 6% and in vivo in six patients at a receptor occupancy of 1%. In vivo recovery and biodistribution kinetics suggested that after in vitro labelling platelets were minimally activated. The /sup 111/In kinetics recorded after intravenous P256 suggested rapid and efficient radiolabelling of platelets and gave no indication of platelet activation. Of the six patients who received intravenous P256, three had documented thrombus, two of whom gave positive results on P256 platelet scintigraphy. The third had chronic deep venous thrombosis and was scintigraphically negative.

Factor analysis of combined organic and inorganic aerosol mass spectra from high resolution aerosol mass spectrometer measurements

Directory of Open Access Journals (Sweden)

Y. L. Sun

2012-09-01

Full Text Available Positive matrix factorization (PMF was applied to the merged high resolution mass spectra of organic and inorganic aerosols from aerosol mass spectrometer (AMS measurements to investigate the sources and evolution processes of submicron aerosols in New York City in summer 2009. This new approach is able to study the distribution of organic and inorganic species in different types of aerosols, the acidity of organic aerosol (OA factors, and the fragment ion patterns related to photochemical processing. In this study, PMF analysis of the unified AMS spectral matrix resolved 8 factors. The hydrocarbon-like OA (HOA and cooking OA (COA factors contain negligible amounts of inorganic species. The two factors that are primarily ammonium sulfate (SO₄-OA and ammonium nitrate (NO₃-OA, respectively, are overall neutralized. Among all OA factors the organic fraction of SO₄-OA shows the highest degree of oxidation (O/C = 0.69. Two semi-volatile oxygenated OA (OOA factors, i.e., a less oxidized (LO-OOA and a more oxidized (MO-OOA, were also identified. MO-OOA represents local photochemical products with a diurnal profile exhibiting a pronounced noon peak, consistent with those of formaldehyde (HCHO and O_x(= O₃ + NO₂. The NO⁺/NO₂⁺ ion ratio in MO-OOA is much higher than that in NO₃-OA and in pure ammonium nitrate, indicating the formation of organic nitrates. The nitrogen-enriched OA (NOA factor contains ~25% of acidic inorganic salts, suggesting the formation of secondary OA via acid-base reactions of amines. The size distributions of OA factors derived from the size-resolved mass spectra show distinct diurnal evolving behaviors but overall a progressing evolution from smaller to larger particle mode as the oxidation degree of OA increases. Our results demonstrate that PMF analysis of the unified aerosol mass spectral matrix which contains both

Characterization of aerosol chemical composition with aerosol mass spectrometry in Central Europe: an overview

Directory of Open Access Journals (Sweden)

V. A. Lanz

2010-11-01

Full Text Available Real-time measurements of non-refractory submicron aerosols (NR-PM₁ were conducted within the greater Alpine region (Switzerland, Germany, Austria, France and Liechtenstein during several week-long field campaigns in 2002–2009. This region represents one of the most important economic and recreational spaces in Europe. A large variety of sites was covered including urban backgrounds, motorways, rural, remote, and high-alpine stations, and also mobile on-road measurements were performed. Inorganic and organic aerosol (OA fractions were determined by means of aerosol mass spectrometry (AMS. The data originating from 13 different field campaigns and the combined data have been utilized for providing an improved temporal and spatial data coverage.

The average mass concentration of NR-PM₁ for the different campaigns typically ranged between 10 and 30 μg m⁻³. Overall, the organic portion was most abundant, ranging from 36% to 81% of NR-PM₁. Other main constituents comprised ammonium (5–15%, nitrate (8–36%, sulfate (3–26%, and chloride (0–5%. These latter anions were, on average, fully neutralized by ammonium. As a major result, time of the year (winter vs. summer and location of the site (Alpine valleys vs. Plateau could largely explain the variability in aerosol chemical composition for the different campaigns and were found to be better descriptors for aerosol composition than the type of site (urban, rural etc.. Thus, a reassessment of classifications of measurements sites might be considered in the future, possibly also for other regions of the world.

The OA data was further analyzed using positive matrix factorization (PMF and the multi-linear engine ME (factor analysis separating the total OA into its underlying components, such as oxygenated (mostly secondary organic aerosol (OOA, hydrocarbon-like and freshly emitted organic aerosol (HOA, as well as OA from biomass

Aerosol and NOx emission factors and submicron particle number size distributions in two road tunnels with different traffic regimes

Directory of Open Access Journals (Sweden)

D. Imhof

2006-01-01

Full Text Available Measurements of aerosol particle number size distributions (18–700 nm, mass concentrations (PM2.5 and PM10 and NOx were performed in the Plabutsch tunnel, Austria, and in the Kingsway tunnel, United Kingdom. These two tunnels show different characteristics regarding the roadway gradient, the composition of the vehicle fleet and the traffic frequency. The submicron particle size distributions contained a soot mode in the diameter range D=80–100 nm and a nucleation mode in the range of D=20–40 nm. In the Kingsway tunnel with a significantly lower particle number and volume concentration level than in the Plabutsch tunnel, a clear diurnal variation of nucleation and soot mode particles correlated to the traffic density was observed. In the Plabutsch tunnel, soot mode particles also revealed a diurnal variation, whereas no substantial variation was found for the nucleation mode particles. During the night a higher number concentration of nucleation mode particles were measured than soot mode particles and vice versa during the day. In this tunnel with very high soot emissions during daytime due to the heavy-duty vehicle (HDV share of 18% and another 40% of diesel driven light-duty vehicles (LDV semivolatile species condense on the pre-existing soot surface area rather than forming new particles by homogeneous nucleation. With the low concentration of soot mode particles in the Kingsway tunnel, also the nucleation mode particles exhibit a diurnal variation. From the measured parameters real-world traffic emission factors were estimated for the whole vehicle fleet as well as differentiated into the two categories LDV and HDV. In the particle size range D=18–700 nm, each vehicle of the mixed fleet emits (1.50±0.08×1014 particles km-1 (Plabutsch and (1.26±0.10×1014 particles km-1 (Kingsway, while particle volume emission factors of 0.209±0.008 cm3 km-1 and 0.036±0.004 cm3 km-1, respectively, were obtained. PM1 emission factors of 104±4 mg

NATO Advanced Study Institute on Physics of Submicron Semiconductor Devices

CERN Document Server

Ferry, David; Jacoboni, C

1988-01-01

The papers contained in the volume represent lectures delivered as a 1983 NATO ASI, held at Urbino, Italy. The lecture series was designed to identify the key submicron and ultrasubmicron device physics, transport, materials and contact issues. Nonequilibrium transport, quantum transport, interfacial and size constraints issues were also highlighted. The ASI was supported by NATO and the European Research Office. H. L. Grubin D. K. Ferry C. Jacoboni v CONTENTS MODELLING OF SUB-MICRON DEVICES.................. .......... 1 E. Constant BOLTZMANN TRANSPORT EQUATION... ... ...... .................... 33 K. Hess TRANSPORT AND MATERIAL CONSIDERATIONS FOR SUBMICRON DEVICES. . .. . . . . .. . . . .. . .. . .... ... .. . . . .. . . . .. . . . . . . . . . . 45 H. L. Grubin EPITAXIAL GROWTH FOR SUB MICRON STRUCTURES.................. 179 C. E. C. Wood INSULATOR/SEMICONDUCTOR INTERFACES.......................... 195 C. W. Wilms en THEORY OF THE ELECTRONIC STRUCTURE OF SEMICONDUCTOR SURFACES AND INTERFACES...................

Bloch-Wave Engineered Submicron Diameter Micropillars with Quality Factors Exceeding 10,000

DEFF Research Database (Denmark)

Hofling, S.; Lermer, M.; Gregersen, Niels

2011-01-01

Adiabatic design submicron diameter quantum-dot micropillars have been designed and implemented for cavity quantum electrodynamics experiments. Ultra-high experimental quality factors (>10,000) are obtained for submicron diameters and strong light-matter interaction is observed....

Hygroscopic behavior of atmospheric aerosols containing nitrate salts and water-soluble organic acids

Science.gov (United States)

Jing, Bo; Wang, Zhen; Tan, Fang; Guo, Yucong; Tong, Shengrui; Wang, Weigang; Zhang, Yunhong; Ge, Maofa

2018-04-01

While nitrate salts have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrate salts remain uncertain. The hygroscopic behaviors of nitrate salt aerosols (NH4NO3, NaNO3, Ca(NO3)2) and their internal mixtures with water-soluble organic acids were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA). The nitrate salt / organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate salt particles show continuous water uptake with increasing relative humidity (RH), the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components, the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-salt-containing aerosols in the atmospheric environment.

Hygroscopic behavior of atmospheric aerosols containing nitrate salts and water-soluble organic acids

Directory of Open Access Journals (Sweden)

B. Jing

2018-04-01

Full Text Available While nitrate salts have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrate salts remain uncertain. The hygroscopic behaviors of nitrate salt aerosols (NH4NO3, NaNO3, Ca(NO32 and their internal mixtures with water-soluble organic acids were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA. The nitrate salt ∕ organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate salt particles show continuous water uptake with increasing relative humidity (RH, the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components, the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-salt-containing aerosols in the atmospheric environment.

Comparison of sources of submicron particle number concentrations measured at two sites in Rochester, NY.

Science.gov (United States)

Kasumba, John; Hopke, Philip K; Chalupa, David C; Utell, Mark J

2009-09-01

Sources contributing to the submicron particles (100-470 nm) measured between January 2002 and December 2007 at two different New York State Department of Environmental Conservation (NYS DEC) sites in Rochester, NY were identified and apportioned using a bilinear receptor model, positive matrix factorization (PMF). Measurements of aerosol size distributions and number concentrations for particles in the size range of 10-500 nm have been made since December 2001 to date in Rochester. The measurements are being made using a scanning mobility particle sizer (SMPS) consisting of a DMA and a CPC (TSI models 3071 and 3010, respectively). From December 2001 to March 2004, particle measurements were made at the NYS DEC site in downtown Rochester, but it was moved to the eastside of Rochester in May 2004. Each measurement period was divided into three seasons i.e., winter (December, January, and February), summer (June, July, and August), and the transitional periods (March, April, May, September, October, and November) so as to avoid experimental uncertainty resulting from too large season-to-season variability in ambient temperature and solar photon intensity that would lead to unstable/non-stationary size distributions. Therefore, the seasons were analyzed independently for possible sources. Ten sources were identified at both sites and these include traffic, nucleation, residential/commercial heating, industrial emissions, secondary nitrate, ozone- rich secondary aerosol, secondary sulfate, regionally transported aerosol, and a mixed source of nucleation and traffic. These results show that the measured total outdoor particle number concentrations in Rochester generally vary with similar temporal patterns, suggesting that the central monitoring site data can be used to estimate outdoor exposure in other parts of the city.

Radiolabeled amino acids : Basic aspects and clinical applications in oncology

NARCIS (Netherlands)

Jager, PL; Vaalburg, W; Pruim, J; de Vries, EGE; Langen, KJ; Piers, DA

As the applications of metabolic imaging are expanding, radiolabeled amino acids may gain increased clinical interest, This review first describes the basic aspects of amino acid metabolism, then continues with basic aspects of radiolabeled amino acids, and finally describes clinical applications,

Portable diffusion battery. It's application to measuring aerosol size characteristics

International Nuclear Information System (INIS)

Sinclair, D.

1972-01-01

A miniature portable cluster-tube diffusion battery for measurement of the size and size distribution of submicron aerosols (1-100 nm) is described. A series of commercially available Collimated Holes Structures are mounted in sleeves with O-rings so that aerosol penetration can be measured at a number of outlets along the series. The CHS are stainless-steel discs of several different diameters and thicknesses, containing a large number of nearly circular holes. The actual length of the apparatus is about 2 ft but the equivalent length is 3.25 mi. Calculated curves of penetration versus particle size are used to evaluate size distribution and show that the equivalent size frequently reported from one measurement with a rectangular diffusion battery is practically meaningless. The value depends as much on the characteristics and mode of the operation of the diffusion battery as on the aerosol; the longer the battery and the lower the air flow, the greater the equivalent size will appear to be. Graphical plots of the cumulative size distribution of room aerosol and silver aerosol are illustrated for large battery and miniature battery measurements and appear to be in close agreement. Measurements on radon daughters in uranium mines with the miniature batteries show activity median diameters from 0.1 to 0.17 micron, with standard deviations from 2 to 4. Two similar measurements made in the laboratory on room air tagged with about 50 pCi/l radon daughters show activity median diameters of 0.15 and 0.17 micron, with geometric standard deviations of 2.2 and 2.6, respectively

Characterization and source apportionment of organic aerosol at 260 m on a meteorological tower in Beijing, China

Science.gov (United States)

Zhou, Wei; Wang, Qingqing; Zhao, Xiujuan; Xu, Weiqi; Chen, Chen; Du, Wei; Zhao, Jian; Canonaco, Francesco; Prévôt, André S. H.; Fu, Pingqing; Wang, Zifa; Worsnop, Douglas R.; Sun, Yele

2018-03-01

Despite extensive efforts toward the characterization of submicron aerosols at ground level in the megacity of Beijing, our understanding of aerosol sources and processes at high altitudes remains low. Here we conducted a 3-month real-time measurement of non-refractory submicron aerosol (NR-PM1) species at a height of 260 m from 10 October 2014 to 18 January 2015 using an aerosol chemical speciation monitor. Our results showed a significant change in aerosol composition from the non-heating period (NHP) to the heating period (HP). Organics and chloride showed clear increases during HP due to coal combustion emissions, while nitrate showed substantial decreases from 28 to 15-18 %. We also found that NR-PM1 species in the heating season can have average mass differences of 30-44 % under similar emission sources yet different meteorological conditions. Multi-linear engine 2 (ME-2) using three primary organic aerosol (OA) factors as constraints, i.e., fossil-fuel-related OA (FFOA) dominantly from coal combustion emissions, cooking OA (COA), and biomass burning OA (BBOA) resolved from ground high-resolution aerosol mass spectrometer measurements, was applied to OA mass spectra of ACSM. Two types of secondary OA (SOA) that were well correlated with nitrate and chloride-CO, respectively, were identified. SOA played a dominant role in OA during all periods at 260 m although the contributions were decreased from 72 % during NHP to 58-64 % during HP. The SOA composition also changed significantly from NHP to HP. While the contribution of oxygenated OA (OOA) was decreased from 56-63 to 32-40 %, less oxidized OOA (LO-OOA) showed a large increase from 9-16 to 24-26 %. COA contributed a considerable fraction of OA at high altitude, and the contribution was relatively similar across different periods (10-13 %). In contrast, FFOA showed a large increase during HP due to the influences of coal combustion emissions. We also observed very different OA composition between ground level

Imaging thrombus with radiolabelled monoclonal antibody to platelets

International Nuclear Information System (INIS)

Loutfi, I.; Peters, A.M.; Lavender, J.P.; Epenetos, A.A.

1988-01-01

Indium-111-hydroxyquinoline labelled platelets, though useful in the detection of thrombus, have not gained widespread use owing to the time and technical skill required for their preparation. A study was therefore conducted evaluating a new method of imaging thrombus with platelets radiolabelled with a 111 In labelled monoclonal antibody, P 256 , directed to the platelet surface glycoprotein complex IIb/IIIa. When the number of receptors occupied by P 256 was less than 3% of the total available on the platelet surface platelet function, as assessed by platelet aggregometry, was undisturbed. P 256 was radiolabelled with 111 In using diethylenetriaminepenta-acetic acid, which achieved a specific activity of 185 MBq (5 mCi)/mg. No impairment of immunoreactivity was detected at this specific activity. Platelets were labelled with radiolabelled monoclonal antibody in vitro in two patients at a receptor occupancy of 6% and in vivo - that is, by direct intravenous injection of P 256 - in six patients at a receptor occupancy of 1%. In vivo recovery and biodistribution kinetics suggested that after in vitro labelling platelets were minimally activated. The 111 In kinetics recorded after intravenous P 256 suggested rapid and efficient radiolabelling of platelets and gave no indication of platelet activation. Of the six patients who received intravenous P 256 , three had documented thrombus, tow of whom gave positive results on P 256 platelet scintigraphy. The third subject had chromic deep venous thrombosis and was scintigraphically negative. Imaging thrombus using a radiolabelled monoclonal antibody directed to platelets appears to offer great potential as a simple, non-invasive approach to the diagnosis of thrombosis. 3 refs. (Author)

Aerosol particles in the Mexican East Pacific Part I: processing and vertical redistribution by clouds

Directory of Open Access Journals (Sweden)

D. Baumgardner

2005-01-01

Full Text Available Airborne measurements of aerosol particle size distributions were made in the Mexican Intertropical Convergence Zone. The volume concentrations of submicron and super micron particles at cloud base were compared with those in near-cloud regions over a range of altitudes. Of 78 near-cloud regions analyzed, 68% and 45% had enhanced volumes of submicron particles and supermicron particles, respectively. In addition, 35% of these regions had supermicron particles removed, presumably by precipitation. In 61% of the cases the enhancement in volume occurred over the size range from 0.1 to 50 μm whereas only submicron volumes were enhanced in 35% of the cases. In regions near clouds that were formed in air of maritime origin the frequency of volume enhancement decreased with increasing altitude and was twice as frequent on the dissipating side of clouds compared to the growing side. No such differences were found in the regions near clouds formed in air originating from the land. The frequency and average magnitude of volume enhancement are in qualitative and quantitative agreement with previous observational and theoretical studies that relate enhancements in particle mass to the uptake by cloud droplets of SO2 accompanied by additional growth by droplet coalescence.

A new technique for radiolabelling of humic substances

International Nuclear Information System (INIS)

Franke, K.; Patt, J.T.; Patt, M.; Kupsch, H.; Steinbach, J.

2004-01-01

A new method of radiolabelling of humic substances (HS) in the aqueous phase has been developed. Radiolabelling with the short-lived positron-emitter 18 F was carried out via diazonium coupling to electron-rich aromatic residues of the humic substances. Labelling yields of up to 75% were obtained after optimization of the synthetic procedure. Introductory experimental steps were performed for testing the labelling stability of the humic substances with ultrafiltration, electrophoretic and chromatographic methods. (orig.)

Radiolabelled peptides for oncological diagnosis

Energy Technology Data Exchange (ETDEWEB)

Laverman, Peter; Boerman, Otto C.; Oyen, Wim J.G. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Sosabowski, Jane K. [Queen Mary University of London, Centre for Molecular Oncology, Barts Cancer Institute, London (United Kingdom)

2012-02-15

Radiolabelled receptor-binding peptides targeting receptors (over)expressed on tumour cells are widely under investigation for tumour diagnosis and therapy. The concept of using radiolabelled receptor-binding peptides to target receptor-expressing tissues in vivo has stimulated a large body of research in nuclear medicine. The {sup 111}In-labelled somatostatin analogue octreotide (OctreoScan trademark) is the most successful radiopeptide for tumour imaging, and was the first to be approved for diagnostic use. Based on the success of these studies, other receptor-targeting peptides such as cholecystokinin/gastrin analogues, glucagon-like peptide-1, bombesin (BN), chemokine receptor CXCR4 targeting peptides, and RGD peptides are currently under development or undergoing clinical trials. In this review, we discuss some of these peptides and their analogues, with regard to their potential for radionuclide imaging of tumours. (orig.)

Size-specific composition of aerosols in the El Chichon volcanic cloud

Science.gov (United States)

Woods, D. C.; Chuan, R. L.

1983-01-01

A NASA U-2 research aircraft flew sampling missions in April, May, July, November, and December 1982 aimed at obtaining in situ data in the stratospheric cloud produced from the March-April 1982 El Chichon eruptions. Post flight analyses provided information on the aerosol composition and morphology. The particles ranged in size from smaller than 0.05 m to larger than 20 m diameter and were quite complex in composition. In the April, May, and July samples the aerosol mass was dominated by magmatic and lithic particles larger than about 3 m. The submicron particles consisted largely of sulfuric acid. Halite particles, believed to be related to a salt dome beneath El Chichon, were collected in the stratosphere in April and May. On the July 23 flight, copper-zinc oxide particles were collected. In July, November, and December, in addition to the volcanic ash and acid particles, carbon-rich particles smaller than about 0.1 m aerodynamic diameter were abundant.

Chitosan Microspheres as Radiolabeled Delivery Devices

International Nuclear Information System (INIS)

Permtermsin, Chalermsin; Ngamprayad, Tippanan; Phumkhem, Sudkanung; Srinuttrakul, Wannee; Kewsuwan, Prartana

2007-08-01

Full text: This study optimized conditions for preparing, characterizing, radiolabeled of chitosan microspheres and the biodistribution of 99mTc-Chitosan microspheres after intravenous administration. Particle size distribution of the microspheres was determined by light scattering. Zeta potential was studied by dynamic light scattering and electrophoresis technique. Biodistribution studies were performed by radiolabeling using 99mTc. The results shown that geometric mean diameter of the microspheres was found to be 77.26?1.96 ?m. Microsphere surface charge of chitosan microspheres was positive charge and zeta potential was 25.80 ? 0.46 mV. The labeling efficiency for this condition was more than 95% and under this condition was stable for at least 6 h. Radioactivity

A new technique for radiolabelling of humic substances

Energy Technology Data Exchange (ETDEWEB)

Franke, K.; Patt, J.T.; Patt, M.; Kupsch, H.; Steinbach, J. [Inst. of Interdisciplinary Isotope Research, Leipzig (Germany)

2004-07-01

A new method of radiolabelling of humic substances (HS) in the aqueous phase has been developed. Radiolabelling with the short-lived positron-emitter {sup 18}F was carried out via diazonium coupling to electron-rich aromatic residues of the humic substances. Labelling yields of up to 75% were obtained after optimization of the synthetic procedure. Introductory experimental steps were performed for testing the labelling stability of the humic substances with ultrafiltration, electrophoretic and chromatographic methods. (orig.)

The inhalation of insoluble iron oxide particles in the sub-micron ranges. Part II - Plutonium-237 labelled aerosols

International Nuclear Information System (INIS)

Waite, D.A.; Ramsden, D.

1971-10-01

The results of a series of inhalation studies using iron oxide particles in the size range 0.1 to 0.3 um (count median diameter) are described. In this series the aerosols were labelled with plutonium 237. In vivo detection, excretion analysis and crude location studies were obtainable and the results compared to the earlier studies using chromium 51 labelled aerosols. Plutonium 237 can be considered as a simulator for plutonium 239 and attempts are made to extrapolate the results to the problem of the estimation of plutonium 239 in the human lung. (author)

Radiolabeling Silica-Based Nanoparticles via Coordination Chemistry: Basic Principles, Strategies, and Applications.

Science.gov (United States)

Ni, Dalong; Jiang, Dawei; Ehlerding, Emily B; Huang, Peng; Cai, Weibo

2018-03-20

As one of the most biocompatible and well-tolerated inorganic nanomaterials, silica-based nanoparticles (SiNPs) have received extensive attention over the last several decades. Recently, positron emission tomography (PET) imaging of radiolabeled SiNPs has provided a highly sensitive, noninvasive, and quantitative readout of the organ/tissue distribution, pharmacokinetics, and tumor targeting efficiency in vivo, which can greatly expedite the clinical translation of these promising NPs. Encouraged by the successful PET imaging of patients with metastatic melanoma using 124 I-labeled ultrasmall SiNPs (known as Cornell dots or C dots) and their approval as an Investigational New Drug (IND) by the United States Food and Drug Administration, different radioisotopes ( 64 Cu, 89 Zr, 18 F, 68 Ga, 124 I, etc.) have been reported to radiolabel a wide variety of SiNPs-based nanostructures, including dense silica (dSiO 2 ), mesoporous silica (MSN), biodegradable mesoporous silica (bMSN), and hollow mesoporous silica nanoparticles (HMSN). With in-depth knowledge of coordination chemistry, abundant silanol groups (-Si-O-) on the silica surface or inside mesoporous channels not only can be directly used for chelator-free radiolabeling but also can be readily modified with the right chelators for chelator-based labeling. However, integrating these labeling strategies for constructing stably radiolabeled SiNPs with high efficiency has proven difficult because of the complexity of the involved key parameters, such as the choice of radioisotopes and chelators, nanostructures, and radiolabeling strategy. In this Account, we present an overview of recent progress in the development of radiolabeled SiNPs for cancer theranostics in the hope of speeding up their biomedical applications and potential translation into the clinic. We first introduce the basic principles and mechanisms for radiolabeling SiNPs via coordination chemistry, including general rules of selecting proper

An introduction to deep submicron CMOS for vertex applications

CERN Document Server

Campbell, M; Cantatore, E; Faccio, F; Heijne, Erik H M; Jarron, P; Santiard, Jean-Claude; Snoeys, W; Wyllie, K

2001-01-01

Microelectronics has become a key enabling technology in the development of tracking detectors for High Energy Physics. Deep submicron CMOS is likely to be extensively used in all future tracking systems. Radiation tolerance in the Mrad region has been achieved and complete readout chips comprising many millions of transistors now exist. The choice of technology is dictated by market forces but the adoption of deep submicron CMOS for tracking applications still poses some challenges. The techniques used are reviewed and some of the future challenges are discussed.

Localization of tumors by radiolabelled antibodies

International Nuclear Information System (INIS)

Hansen, H.J.; Primus, F.J.

1975-01-01

A method of utilizing radiolabelled antibodies to carcinoembryonic antigens for determining the site of tumors which produce or are associated with carcinoembryonic antigen is disclosed. 3 claims, no drawings

Cost-effectiveness of Low-dose Submicron Diclofenac Compared With Generic Diclofenac.

Science.gov (United States)

Mladsi, Deirdre; Ronquest, Naoko; Odom, Dawn; Miles, LaStella; Saag, Kenneth

2016-11-01

NSAIDs are commonly prescribed for the treatment of pain and inflammation. Despite the effectiveness of NSAIDs, concerns exist regarding their tolerability. Worldwide health authorities, including the European Medicines Agency, Health Canada, and the US Food and Drug Administration, have advised that NSAIDs be prescribed at the lowest effective dosage and for the shortest duration. Effective lowering of NSAID dosage without compromising pain relief has been demonstrated in randomized, controlled trials of the recently approved NSAID lower-dose submicron diclofenac. Building on previously published work from an independently published systematic review and meta-analysis, a linear dose-toxicity relationship between diclofenac dose and serious gastrointestinal (GI) events was recently demonstrated, indicating that reductions in adverse events (AEs) may be seen even with modest dose reductions in many patients. The objective of the present study was to estimate the potential reduction in risk for NSAID dose-related AEs, corresponding savings in health care costs, and the incremental cost-effectiveness of submicron diclofenac compared with generic diclofenac in the United States. Our decision-analytic cost-effectiveness model considered a subset of potential AEs that may be avoided by lowering NSAID dosage. To estimate the expected reductions in upper GI bleeding/perforation and major cardiovascular events with submicron diclofenac, our model used prediction equations estimated by meta-regressions using data from systematic literature reviews. Utilities, lifetime costs, and health outcomes associated with AEs were estimated using data from the literature. The face validity of the model structure and inputs was confirmed by clinical experts in the United States. Results were evaluated in 1-way and probabilistic sensitivity analyses. The model predicted that submicron diclofenac versus generic diclofenac could reduce the occurrence of modeled GI events (by 18

Aerosol particle measurements at three stationary sites in the megacity of Paris during summer 2009: meteorology and air mass origin dominate aerosol particle composition and size distribution

Directory of Open Access Journals (Sweden)

F. Freutel

2013-01-01

Full Text Available During July 2009, a one-month measurement campaign was performed in the megacity of Paris. Amongst other measurement platforms, three stationary sites distributed over an area of 40 km in diameter in the greater Paris region enabled a detailed characterization of the aerosol particle and gas phase. Simulation results from the FLEXPART dispersion model were used to distinguish between different types of air masses sampled. It was found that the origin of air masses had a large influence on measured mass concentrations of the secondary species particulate sulphate, nitrate, ammonium, and oxygenated organic aerosol measured with the Aerodyne aerosol mass spectrometer in the submicron particle size range: particularly high concentrations of these species (about 4 μg m⁻³, 2 μg m⁻³, 2 μg m⁻³, and 7 μg m⁻³, respectively were measured when aged material was advected from continental Europe, while for air masses originating from the Atlantic, much lower mass concentrations of these species were observed (about 1 μg m⁻³, 0.2 μg m⁻³, 0.4 μg m⁻³, and 1–3 μg m⁻³, respectively. For the primary emission tracers hydrocarbon-like organic aerosol, black carbon, and NO_x it was found that apart from diurnal source strength variations and proximity to emission sources, local meteorology had the largest influence on measured concentrations, with higher wind speeds leading to larger dilution and therefore smaller measured concentrations. Also the shape of particle size distributions was affected by wind speed and air mass origin. Quasi-Lagrangian measurements performed under connected flow conditions between the three stationary sites were used to estimate the influence of the Paris emission plume onto its surroundings, which was found to be rather small. Rough estimates for the impact of the Paris emission plume on the suburban areas can be

Scanning SQUID susceptometers with sub-micron spatial resolution

Energy Technology Data Exchange (ETDEWEB)

Kirtley, John R., E-mail: jkirtley@stanford.edu; Rosenberg, Aaron J.; Palmstrom, Johanna C.; Holland, Connor M.; Moler, Kathryn A. [Department of Applied Physics, Stanford University, Stanford, California 94305-4045 (United States); Paulius, Lisa [Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008-5252 (United States); Spanton, Eric M. [Department of Physics, Stanford University, Stanford, California 94305-4045 (United States); Schiessl, Daniel [Attocube Systems AG, Königinstraße 11A, 80539 Munich (Germany); Jermain, Colin L.; Gibbons, Jonathan [Department of Physics, Cornell University, Cornell, Ithaca, New York 14853 (United States); Fung, Y.-K.K.; Gibson, Gerald W. [IBM Research Division, T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Huber, Martin E. [Department of Physics, University of Colorado Denver, Denver, Colorado 80217-3364 (United States); Ralph, Daniel C. [Department of Physics, Cornell University, Cornell, Ithaca, New York 14853 (United States); Kavli Institute at Cornell, Ithaca, New York 14853 (United States); Ketchen, Mark B. [OcteVue, Hadley, Massachusetts 01035 (United States)

2016-09-15

Superconducting QUantum Interference Device (SQUID) microscopy has excellent magnetic field sensitivity, but suffers from modest spatial resolution when compared with other scanning probes. This spatial resolution is determined by both the size of the field sensitive area and the spacing between this area and the sample surface. In this paper we describe scanning SQUID susceptometers that achieve sub-micron spatial resolution while retaining a white noise floor flux sensitivity of ≈2μΦ{sub 0}/Hz{sup 1/2}. This high spatial resolution is accomplished by deep sub-micron feature sizes, well shielded pickup loops fabricated using a planarized process, and a deep etch step that minimizes the spacing between the sample surface and the SQUID pickup loop. We describe the design, modeling, fabrication, and testing of these sensors. Although sub-micron spatial resolution has been achieved previously in scanning SQUID sensors, our sensors not only achieve high spatial resolution but also have integrated modulation coils for flux feedback, integrated field coils for susceptibility measurements, and batch processing. They are therefore a generally applicable tool for imaging sample magnetization, currents, and susceptibilities with higher spatial resolution than previous susceptometers.

Scanning SQUID susceptometers with sub-micron spatial resolution

International Nuclear Information System (INIS)

Kirtley, John R.; Rosenberg, Aaron J.; Palmstrom, Johanna C.; Holland, Connor M.; Moler, Kathryn A.; Paulius, Lisa; Spanton, Eric M.; Schiessl, Daniel; Jermain, Colin L.; Gibbons, Jonathan; Fung, Y.-K.K.; Gibson, Gerald W.; Huber, Martin E.; Ralph, Daniel C.; Ketchen, Mark B.

2016-01-01

Superconducting QUantum Interference Device (SQUID) microscopy has excellent magnetic field sensitivity, but suffers from modest spatial resolution when compared with other scanning probes. This spatial resolution is determined by both the size of the field sensitive area and the spacing between this area and the sample surface. In this paper we describe scanning SQUID susceptometers that achieve sub-micron spatial resolution while retaining a white noise floor flux sensitivity of ≈2μΦ_0/Hz"1"/"2. This high spatial resolution is accomplished by deep sub-micron feature sizes, well shielded pickup loops fabricated using a planarized process, and a deep etch step that minimizes the spacing between the sample surface and the SQUID pickup loop. We describe the design, modeling, fabrication, and testing of these sensors. Although sub-micron spatial resolution has been achieved previously in scanning SQUID sensors, our sensors not only achieve high spatial resolution but also have integrated modulation coils for flux feedback, integrated field coils for susceptibility measurements, and batch processing. They are therefore a generally applicable tool for imaging sample magnetization, currents, and susceptibilities with higher spatial resolution than previous susceptometers.

Submicron Resolution Spectral-Domain Optical Coherence Tomography

KAUST Repository

Alarousu, Erkki; Jabbour, Ghassan

2013-01-01

Apparatuses and systems for submicron resolution spectral-domain optical coherence tomography (OCT) are disclosed. The system may use white light sources having wavelengths within 400-1000 nanometers, and achieve resolution below 1 .mu

In vitro incorporation of radiolabeled cholesteryl esters into high and low density lipoproteins

International Nuclear Information System (INIS)

Terpstra, A.H.; Nicolosi, R.J.; Herbert, P.N.

1989-01-01

We have developed and validated a method for in vitro incorporation of radiolabeled cholesteryl esters into low density (LDL) and high density lipoproteins (HDL). Radiolabeled cholesteryl esters dissolved in absolute ethanol were mixed with LDL or HDL in the presence of lipoprotein-deficient serum (LPDS) as a source of core lipid transfer activity. The efficiency of incorporation was dependent on: (a) the core lipid transfer activity and quantity of LPDS, (b) the mass of added radiolabeled cholesteryl esters, (c) the length of incubation, and (d) the amount of acceptor lipoprotein cholesterol. The tracer incorporation was documented by repeat density gradient ultracentrifugation, agarose gel electrophoresis, and precipitation with heparin-MnCl2. The radiolabeling conditions did not affect the following properties of the lipoproteins: (1) chemical composition, (2) electrophoretic mobility on agarose gels, (3) hydrated density, (4) distribution of apoproteins on SDS gels, (5) plasma clearance rates, and (6) immunoprecipitability of HDL apoproteins A-I and A-II. Rat HDL containing radiolabeled cholesteryl esters incorporated in vitro had plasma disappearance rates identical to HDL radiolabeled in vivo

Chemical composition, sources and secondary processes of aerosols in Baoji city of northwest China

Science.gov (United States)

Wang, Y. C.; Huang, R.-J.; Ni, H. Y.; Chen, Y.; Wang, Q. Y.; Li, G. H.; Tie, X. X.; Shen, Z. X.; Huang, Y.; Liu, S. X.; Dong, W. M.; Xue, P.; Fröhlich, R.; Canonaco, F.; Elser, M.; Daellenbach, K. R.; Bozzetti, C.; El Haddad, I.; Prévôt, A. S. H.; Canagaratna, M. R.; Worsnop, D. R.; Cao, J. J.

2017-06-01

Particulate air pollution is a severe environmental problem in China, affecting visibility, air quality, climate and human health. However, previous studies focus mainly on large cities such as Beijing, Shanghai, and Guangzhou. In this study, an Aerodyne Aerosol Chemical Speciation Monitor was deployed in Baoji, a middle size inland city in northwest China from 26 February to 27 March 2014. The non-refractory submicron aerosol (NR-PM1) was dominated by organics (55%), followed by sulfate (16%), nitrate (15%), ammonium (11%) and chloride (3%). A source apportionment of the organic aerosol (OA) was performed with the Sofi (Source Finder) interface of ME-2 (Multilinear Engine), and six main sources/factors were identified and classified as hydrocarbon-like OA (HOA), cooking OA (COA), biomass burning OA (BBOA), coal combustion OA (CCOA), less oxidized oxygenated OA (LO-OOA) and more oxidized oxygenated OA (MO-OOA), which contributed 20%, 14%, 13%, 9%, 23% and 21% of total OA, respectively. The contribution of secondary components shows increasing trends from clean days to polluted days, indicating the importance of secondary aerosol formation processes in driving particulate air pollution. The formation of LO-OOA and MO-OOA is mainly driven by photochemical reactions, but significantly influenced by aqueous-phase chemistry during periods of low atmospheric oxidative capacity.

New surface radiolabeling schemes of super paramagnetic iron oxide nanoparticles (SPIONs) for biodistribution studies.

Science.gov (United States)

Nallathamby, Prakash D; Mortensen, Ninell P; Palko, Heather A; Malfatti, Mike; Smith, Catherine; Sonnett, James; Doktycz, Mitchel J; Gu, Baohua; Roeder, Ryan K; Wang, Wei; Retterer, Scott T

2015-04-21

Nanomaterial based drug delivery systems allow for the independent tuning of the surface chemical and physical properties that affect their biodistribution in vivo and the therapeutic payloads that they are intended to deliver. Additionally, the added therapeutic and diagnostic value of their inherent material properties often provides extra functionality. Iron based nanomaterials with their magnetic properties and easily tailorable surface chemistry are of particular interest as model systems. In this study the core radius of the iron oxide nanoparticles (NPs) was 14.08 ± 3.92 nm while the hydrodynamic radius of the NPs, as determined by Dynamic Light Scattering (DLS), was between 90-110 nm. In this study, different approaches were explored to create radiolabeled NPs that are stable in solution. The NPs were functionalized with polycarboxylate or polyamine surface functional groups. Polycarboxylate functionalized NPs had a zeta potential of -35 mV and polyamine functionalized NPs had a zeta potential of +40 mV. The polycarboxylate functionalized NPs were chosen for in vivo biodistribution studies and hence were radiolabeled with (14)C, with a final activity of 0.097 nCi mg(-1) of NPs. In chronic studies, the biodistribution profile is tracked using low level radiolabeled proxies of the nanoparticles of interest. Conventionally, these radiolabeled proxies are chemically similar but not chemically identical to the non-radiolabeled NPs of interest. This study is novel as different approaches were explored to create radiolabeled NPs that are stable, possess a hydrodynamic radius of <100 nm and most importantly they exhibit an identical surface chemical functionality as their non-radiolabeled counterparts. Identical chemical functionality of the radiolabeled probes to the non-radiolabeled probes was an important consideration to generate statistically similar biodistribution data sets using multiple imaging and detection techniques. The radiolabeling approach

Characteristics of Aerosol Transport from Asia to the West Coast of North America

Science.gov (United States)

Brock, C. A.; Bahreini, R.; Middlebrook, A. M.; Atlas, E. L.; Blake, D. R.; Brioude, J.; Cooper, O. R.; de Gouw, J. A.; Holloway, J. S.; Lack, D. A.; Langridge, J. M.; Meinardi, S.; Nowak, J. B.; Peischl, J.; Perring, A.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Schwarz, J. P.; Spackman, J. R.; Trainer, M.; Trytko, J.; Warneke, C.

2010-12-01

During the CalNex field program of May and June 2010, the NOAA WP-3D aircraft observed several layers of enhanced trace gas mixing ratios and aerosol concentrations at altitudes ranging from 1 to 4 km over southern and central California. The submicron aerosol composition within these layers was dominated by partially neutralized sulfate, while nitrate, organic matter and black carbon were only minor constituents. The particle layers were associated with trace gases, such as benzene and sulfur dioxide, consistent with anthropogenic fossil fuel emissions, and were not associated with enhancements of the biomass burning tracer acetonitrile. The particle size distribution was dominated by a single accumulation mode that is characteristic of a well aged aerosol. Transport modeling indicates an Asian source for these layers of pollution. Dew point temperatures within the layers were less than -15 degrees Celsius, indicating desiccation by precipitation during transport. Taken together, these observations are consistent with those from earlier studies in which was diagnosed the removal of primary and organic particles by precipitation scavenging during uplift from the polluted Asian boundary layer into the free troposphere. Oxidation of residual sulfur dioxide that remained following transport through the cloud system may have resulted in the observed sulfate-rich aerosol. The repeated observation of such layers suggests that wet scavenging frequently modifies the chemical and optical characteristics of aerosols emitted in urban regions in Asia and transported in the free troposphere across the Pacific.

Use of metallic glasses for fabrication of structures with submicron dimensions

Science.gov (United States)

Wiley, John D.; Perepezko, John H.

1986-01-01

Patterned structures of submicron dimension formed of supported or unsupported amorphous metals having submicron feature sizes characterized by etching behavior sufficient to allow delineation of sharp edges and smooth flat flanks, resistance to time-dependent dimensional changes caused by creep, flow, in-diffusion of unwanted impurities, out-diffusion of constituent atoms, void formation, grain growth or phase separation and resistance to phase transformations or compound formation.

Organic functional groups in the submicron aerosol at 82.5° N, 62.5° W from 2012 to 2014

Science.gov (United States)

Leaitch, W. Richard; Russell, Lynn M.; Liu, Jun; Kolonjari, Felicia; Toom, Desiree; Huang, Lin; Sharma, Sangeeta; Chivulescu, Alina; Veber, Dan; Zhang, Wendy

2018-03-01

The first multi-year contributions from organic functional groups to the Arctic submicron aerosol are documented using 126 weekly-integrated samples collected from April 2012 to October 2014 at the Alert Observatory (82.45° N, 62.51° W). Results from the particle transport model FLEXPART, linear regressions among the organic and inorganic components and positive matrix factorization (PMF) enable associations of organic aerosol components with source types and regions. Lower organic mass (OM) concentrations but higher ratios of OM to non-sea-salt sulfate mass concentrations (nss-SO4=) accompany smaller particles during the summer (JJA). Conversely, higher OM but lower OM / nss-SO4= accompany larger particles during winter-spring. OM ranges from 7 to 460 ng m-3, and the study average is 129 ng m-3. The monthly maximum in OM occurs during May, 1 month after the peak in nss-SO4= and 2 months after that of elemental carbon (EC). Winter (DJF), spring (MAM), summer and fall (SON) values of OM / nss-SO4= are 26, 28, 107 and 39 %, respectively, and overall about 40 % of the weekly variability in the OM is associated with nss-SO4=. Respective study-averaged concentrations of alkane, alcohol, acid, amine and carbonyl groups are 57, 24, 23, 15 and 11 ng m-3, representing 42, 22, 18, 14 and 5 % of the OM, respectively. Carbonyl groups, detected mostly during spring, may have a connection with snow chemistry. The seasonally highest O / C occurs during winter (0.85) and the lowest O / C is during spring (0.51); increases in O / C are largely due to increases in alcohol groups. During winter, more than 50 % of the alcohol groups are associated with primary marine emissions, consistent with Shaw et al. (2010) and Frossard et al. (2011). A secondary marine connection, rather than a primary source, is suggested for the highest and most persistent O / C observed during the coolest and cleanest summer (2013), when alcohol and acid groups made up 63 % of the OM. A secondary marine

Composition of Radioactive Aerosols in the Shelter Construction of the Chernobyl Nuclear Power Plant in 2000-2015

Science.gov (United States)

Ogorodnikov, B. I.

2018-06-01

The results of the physicochemical studies of radioactive aerosols inside and outside the Shelter construction at the Arch construction stage of the Chernobyl Nuclear Power Plant (ChNPP) in 2000-2015 were presented. The dominant isotopes were shown to be cesium, strontium, americium, plutonium, and uranium. They are carried by disperse particles of 2-7 μm. In subreactor rooms, in particular, 012/7, the composition of aerosols is affected by the erosion of the fuel-containing mass formed in 1986. Submicron cesium carrier aerosols appear as a result of evaporation and condensation during fires and welding works. Radiocesium is a well-soluble component of aerosols, while plutonium isotopes are not readily soluble components. In several rooms, the contents of radon, thoron, and their daughter products exceeded the permissible values. In April-June 2011, the intake of radionuclides from the accident at the Japanese Fukushima-1 NPP, which had AMAD of 0.5 μm, was detected and tracked using Petryanov multilayer filters. The productivity of filtration units under the dusty conditions in the exclusion zone of ChNPP and in fogs and haze was investigated. Hydrophilic prefilters with 7-10 μm fibers were recommended.

Aerosol composition and sources in the central Arctic Ocean during ASCOS

Science.gov (United States)

Chang, R. Y.-W.; Leck, C.; Graus, M.; Müller, M.; Paatero, J.; Burkhart, J. F.; Stohl, A.; Orr, L. H.; Hayden, K.; Li, S.-M.; Hansel, A.; Tjernström, M.; Leaitch, W. R.; Abbatt, J. P. D.

2011-10-01

Measurements of submicron aerosol chemical composition were made over the central Arctic Ocean from 5 August to 8 September 2008 as a part of the Arctic Summer Cloud Ocean Study (ASCOS) using an aerosol mass spectrometer (AMS). The median levels of sulphate and organics for the entire study were 0.051 and 0.055 μ g m-3, respectively. Positive matrix factorisation was performed on the entire mass spectral time series and this enabled marine biogenic and continental sources of particles to be separated. These factors accounted for 33% and 36% of the sampled ambient aerosol mass, respectively, and they were both predominantly composed of sulphate, with 47% of the sulphate apportioned to marine biogenic sources and 48% to continental sources, by mass. Within the marine biogenic factor, the ratio of methane sulphonate to sulphate was 0.25 ± 0.02, consistent with values reported in the literature. The organic component of the continental factor was more oxidised than that of the marine biogenic factor, suggesting that it had a longer photochemical lifetime than the organics in the marine biogenic factor. The remaining ambient aerosol mass was apportioned to an organic-rich factor that could have arisen from a combination of marine and continental sources. In particular, given that the factor does not correlate with common tracers of continental influence, we cannot rule out that the organic factor arises from a primary marine source.

Penetration of sub-micron aerosol droplets in composite cylindrical filtration elements

International Nuclear Information System (INIS)

Geurts, Bernard J.; Pratte, Pascal; Stolz, Steffen; Stabbert, Regina; Poux, Valerie; Nordlund, Markus; Winkelmann, Christoph

2011-01-01

Advection-diffusion transport of aerosol droplets in composite cylindrical filtration elements is analyzed and compared to experimental data. The penetration, characterizing the fraction of droplets that passes through the pores of a filtration element, is quantified for a range of flow rates. The advection-diffusion transport in a laminar Poiseuille flow is treated numerically for slender pores using a finite difference approach in cylindrical coordinates. The algebraic dependence of the penetration on the Peclet number as predicted theoretically, is confirmed by experimental findings at a variety of aspect ratios of the cylindrical pores. The effective penetration associated with a composite filtration element consisting of a set of parallel cylindrical pores is derived. The overall penetration of heterogeneous composite filtration elements shows an algebraic dependence to the fourth power on the radii of the individual pores that are contained. This gives rise to strong variations in the overall penetration in cases with uneven distributions of pore sizes, highly favoring filtration by the larger pores. The overall penetration is computed for a number of basic geometries, providing a point of reference for filtration design and experimental verification.

Characteristics and composition of atmospheric aerosols in Phimai, central Thailand during BASE-ASIA

Science.gov (United States)

Li, Can; Tsay, Si-Chee; Hsu, N. Christina; Kim, Jin Young; Howell, Steven G.; Huebert, Barry J.; Ji, Qiang; Jeong, Myeong-Jae; Wang, Sheng-Hsiang; Hansell, Richard A.; Bell, Shaun W.

2013-10-01

Comprehensive measurements of atmospheric aerosols were made in Phimai, central Thailand (15.183°N, 102.565°E, elevation: 206 m) during the BASE-ASIA field experiment from late February to early May in 2006. The observed aerosol loading was sizable for this rural site (mean aerosol scattering: 108 ± 64 Mm-1; absorption: 15 ± 8 Mm-1; PM10 concentration: 33 ± 17 μg m-3), and dominated by submicron particles. Major aerosol compounds included carbonaceous (OC: 9.5 ± 3.6 μg m-3; EC: 2.0 ± 2.3 μg m-3) and secondary species (SO42-: 6.4 ± 3.7 μg m-3, NH4+: 2.2 ± 1.3 μg m-3). While the site was seldom under the direct influence of large forest fires to its north, agricultural fires were ubiquitous during the experiment, as suggested by the substantial concentration of K+ (0.56 ± 0.33 μg m-3). Besides biomass burning, aerosols in Phimai during the experiment were also strongly influenced by industrial and vehicular emissions from the Bangkok metropolitan region and long-range transport from southern China. High humidity played an important role in determining the aerosol composition and properties in the region. Sulfate was primarily formed via aqueous phase reactions, and hygroscopic growth could enhance the aerosol light scattering by up to 60%, at the typical morning RH level of 85%. The aerosol single scattering albedo demonstrated distinct diurnal variation, ranging from 0.86 ± 0.04 in the evening to 0.92 ± 0.02 in the morning. This experiment marks the first time such comprehensive characterization of aerosols was made for rural central Thailand. Our results indicate that aerosol pollution has developed into a regional problem for northern Indochina, and may become more severe as the region's population and economy continue to grow.

Parameters influencing the aerosol capture performance of the Submerged-Bed Scrubber

International Nuclear Information System (INIS)

Ruecker, C.M.; Scott, P.A.

1987-04-01

The Submerged-Bed Scrubber (SBS) is a novel air cleaning device that has been investigated by Pacific Northwest Laboratory (PNL) for scrubbing off gases from liquid-fed ceramic melters used to vitrify high-level waste (HLW). The concept for the SBS was originally conceived at Hanford for emergency venting of a reactor containment building. The SBS was adapted for use as a quenching scrubber at PNL because it can cool the hot melter off gas as well as remove over 90% of the airborne particles, thus meeting the minimum particulate decontamination factor (DF) of 10 required of a primary scrubber. The experiments in this study showed that the submicron aerosol DF for the SBS can exceed 100 under certain conditions. A conventional device, the ejector-venturi scrubber (EVS), has been previously used in this application. The EVS also adequately cools the hot gases from the melter while exhibiting aerosol removal DFs in the range of 5 to 30. In addition to achieving higher DFs than the EVS, however, the SBS has the advantage of being a passive system, better suited to the remote environment of an HLW processing system. The objective of this study was to characterize the performance of the SBS and to improve the aerosol capture efficiency by modifying the operating procedure or the design. A partial factorial experimental matrix was completed to determine the main effects of aerosol solubility, inlet off-gas temperature, inlet off-gas flow rate, steam-to-air ratio, bed diameter and packing diameter on the particulate removal efficiency of the SBS. Several additional experiments were conducted to measure the influence of the inlet aerosol concentration and scrubbing-water concentration on aerosol-removal performance. 33 refs., 17 figs., 14 tabs

Electrosprayed Polyvinylpyrrolidone (PVP) Submicron Particles Loaded by Green Tea Extracts

Science.gov (United States)

Kamaruddin; Sriyanti, I.; Edikresnha, D.; Munir, M. M.; Khairurrijal, K.

2018-05-01

Electrospraying technique has been successfully used to synthesize composite submicron particles of polyvinylpyrrolidone (PVP) and green tea extract (GTE). The precursor solutions were PVP in ethanol (15 wt%) and GTE in ethanol (10 wt%), which were then mixed at varying ratio. The mixed solution then underwent electrospraying process at an applied voltage of 15 kV, a distance of collector to the nozzle at 15 cm, and a flow rate of 3 µL/min. The composite submicron particles of PVP-GTE showed smooth and fine spherical morphology without fibers or beaded fibers. To a certain degree, the increase of GTE content in the PVP-GTE mixed solution decreased the average diameter of PVP-GTE composite particles. Moreover, the analysis of the FTIR spectra confirmed the existing molecular interaction between PVP and GTE in the composite submicron particles as shown by the shift of PVP wavenumber towards GTE, which has typically smaller wavenumber.

Recent advances in understanding secondary organic aerosol: Implications for global climate forcing

Science.gov (United States)

Shrivastava, Manish; Cappa, Christopher D.; Fan, Jiwen; Goldstein, Allen H.; Guenther, Alex B.; Jimenez, Jose L.; Kuang, Chongai; Laskin, Alexander; Martin, Scot T.; Ng, Nga Lee; Petaja, Tuukka; Pierce, Jeffrey R.; Rasch, Philip J.; Roldin, Pontus; Seinfeld, John H.; Shilling, John; Smith, James N.; Thornton, Joel A.; Volkamer, Rainer; Wang, Jian; Worsnop, Douglas R.; Zaveri, Rahul A.; Zelenyuk, Alla; Zhang, Qi

2017-06-01

Anthropogenic emissions and land use changes have modified atmospheric aerosol concentrations and size distributions over time. Understanding preindustrial conditions and changes in organic aerosol due to anthropogenic activities is important because these features (1) influence estimates of aerosol radiative forcing and (2) can confound estimates of the historical response of climate to increases in greenhouse gases. Secondary organic aerosol (SOA), formed in the atmosphere by oxidation of organic gases, represents a major fraction of global submicron-sized atmospheric organic aerosol. Over the past decade, significant advances in understanding SOA properties and formation mechanisms have occurred through measurements, yet current climate models typically do not comprehensively include all important processes. This review summarizes some of the important developments during the past decade in understanding SOA formation. We highlight the importance of some processes that influence the growth of SOA particles to sizes relevant for clouds and radiative forcing, including formation of extremely low volatility organics in the gas phase, acid-catalyzed multiphase chemistry of isoprene epoxydiols, particle-phase oligomerization, and physical properties such as volatility and viscosity. Several SOA processes highlighted in this review are complex and interdependent and have nonlinear effects on the properties, formation, and evolution of SOA. Current global models neglect this complexity and nonlinearity and thus are less likely to accurately predict the climate forcing of SOA and project future climate sensitivity to greenhouse gases. Efforts are also needed to rank the most influential processes and nonlinear process-related interactions, so that these processes can be accurately represented in atmospheric chemistry-climate models.

Fabrication, microstructure, and mechanical properties of high strength cobalt sub-micron structures

International Nuclear Information System (INIS)

Jin Sumin; Burek, Michael J.; Evans, Robert D.; Jahed, Zeinab; Leung, Michael C.; Evans, Neal D.; Tsui, Ting Y.

2012-01-01

The mechanical properties exhibited by sub-micron scale columnar structures of cobalt, fabricated by electron beam lithography and electroplating techniques, were investigated through uniaxial compression. Transmission electron microscopy analyses show these specimens possess a microstructure with sub-micron grains which are elongated and aligned near to the pillar loading axis. In addition, small nanocrystalline cobalt crystals are also present within the columnar structure. These specimens display exceptional mechanical strength comparable with both bulk polycrystalline and nanocrystalline cobalt deposited by electroplating. Size-dependent softening with shrinking sample dimensions is also observed in this work. Additionally, the strength of these sub-micron structures appears to be strain rate sensitive and comparable with bulk nanocrystalline cobalt specimens.

Seasonal differences in the vertical profiles of aerosol optical properties over rural Oklahoma

Directory of Open Access Journals (Sweden)

E. Andrews

2011-10-01

Full Text Available A small airplane made 597 aerosol optical property (light absorption and light scattering vertical profile measurements over a rural Oklahoma site between March 2000 and December 2007. The aerosol profiles obtained during these 8 yr of measurements suggest significant seasonal differences in aerosol loading (scattering and absorption. The highest amounts of scattering and absorbing aerosol are observed during the summer and the lowest loading occurs during the winter. The relative contribution of aerosol absorption is highest in the winter (i.e., single scattering albedo is lowest in winter, particularly aloft. Aerosol absorption generally decreased with altitude below ~1.5 km and then was relatively constant or decreased more gradually above that. Aerosol scattering decreased sharply with altitude below ~1.5 km but, unlike absorption, also decreased at higher altitudes, albeit less sharply. Scattering Ångström exponents suggest that the aerosol was dominated by sub-micron aerosol during the summer at all altitudes, but that larger particles were present, especially in the spring and winter above 1 km. The seasonal variability observed for aerosol loading is consistent with AERONET aerosol optical depth (AOD although the AOD values calculated from in situ adjusted to ambient conditions and matching wavelengths are up to a factor of two lower than AERONET AOD values depending on season. The column averaged single scattering albedo derived from in situ airplane measurements are similar in value to the AERONET single scattering albedo inversion product but the seasonal patterns are different – possibly a consequence of the strict constraints on obtaining single scattering albedo from AERONET data. A comparison of extinction Ångström exponent and asymmetry parameter from the airplane and AERONET platforms suggests similar seasonal variability with smaller particles observed in the summer and fall and larger particles observed in spring and

New surface radiolabeling schemes of super paramagnetic iron oxide nanoparticles (SPIONs) for biodistribution studies†

Science.gov (United States)

Nallathamby, Prakash D.; Mortensen, Ninell P.; Palko, Heather A.; Malfatti, Mike; Smith, Catherine; Sonnett, James; Doktycz, Mitchel J.; Gu, Baohua; Roeder, Ryan K.; Wang, Wei; Retterer, Scott T.

2016-01-01

Nanomaterial based drug delivery systems allow for the independent tuning of the surface chemical and physical properties that affect their biodistribution in vivo and the therapeutic payloads that they are intended to deliver. Additionally, the added therapeutic and diagnostic value of their inherent material properties often provides extra functionality. Iron based nanomaterials with their magnetic properties and easily tailorable surface chemistry are of particular interest as model systems. In this study the core radius of the iron oxide nanoparticles (NPs) was 14.08 ± 3.92 nm while the hydrodynamic radius of the NPs, as determined by Dynamic Light Scattering (DLS), was between 90–110 nm. In this study, different approaches were explored to create radiolabeled NPs that are stable in solution. The NPs were functionalized with polycarboxylate or polyamine surface functional groups. Polycarboxylate functionalized NPs had a zeta potential of –35 mV and polyamine functionalized NPs had a zeta potential of +40 mV. The polycarboxylate functionalized NPs were chosen for in vivo biodistribution studies and hence were radiolabeled with 14C, with a final activity of 0.097 nCi mg–1 of NPs. In chronic studies, the biodistribution profile is tracked using low-level radiolabeled proxies of the nanoparticles of interest. Conventionally, these radiolabeled proxies are chemically similar but not chemically identical to the non-radiolabeled NPs of interest. This study is novel as different approaches were explored to create radiolabeled NPs that are stable, possess a hydrodynamic radius of <100 nm and most importantly they exhibit an identical surface chemical functionality as their non-radiolabeled counterparts. Identical chemical functionality of the radiolabeled probes to the non-radiolabeled probes was an important consideration to generate statistically similar biodistribution data sets using multiple imaging and detection techniques. The radiolabeling approach

Potential sea salt aerosol sources from frost flowers in the pan-Arctic region

Energy Technology Data Exchange (ETDEWEB)

Xu, Li [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Now at Department of Earth System Science, University of California, Irvine California USA; Russell, Lynn M. [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Burrows, Susannah M. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA

2016-09-23

In order to better represent observed wintertime aerosol concentrations at Barrow, Alaska, we implemented an observationally-based parameterization for estimating sea salt production from frost flowers in the Community Earth System Model (CESM). In this work, we evaluate the potential influence of this sea salt source on the pan-Arctic (60ºN-90ºN) climate. Results show that frost flower salt emissions substantially increase the modeled surface sea salt aerosol concentration in the winter months when new sea ice and frost flowers are present. The parameterization reproduces both the magnitude and seasonal variation of the observed submicron sea salt aerosol concentration at surface in Barrow during winter much better than the standard CESM simulation without a frost-flower salt particle source. Adding these frost flower salt particle emissions increases aerosol optical depth by 10% and results in a small cooling at surface. The increase in salt particle mass concentrations of a factor of 8 provides nearly two times the cloud condensation nuclei concentration, as well as 10% increases in cloud droplet number and 40% increases in liquid water content near coastal regions adjacent to continents. These cloud changes reduce longwave cloud forcing by 3% and cause a small surface warming, increasing the downward longwave flux at the surface by 2 W m-2 in the pan-Arctic under the present-day climate.

Detection of inflammatory lesions with radiolabelled immunoglobulins

International Nuclear Information System (INIS)

Blok, D.; Rijksuniversiteit Leiden; Ogtrop, M. van; Arndt, J.W.; Camps, J.A.J.; Feitsma, R.I.J.; Pauwels, E.K.J.

1990-01-01

Previous reports on the use of radiolabelled immunoglobulins led us to undertake a pilot experiment in an animal model to investigate the potentials sodium pertechnate Tc 99m-immunoglobulin scintigraphy in the detection of infectious foci. Mice infected in one leg with staphylococcus infection in were injected with sodium pertechnote Tc 99m-immunoglobulin, albumin aggregated technetium Tc 99m or gallium citrate Ga 67. The results obtained by scintigraphy suggested a specific accumulation of radiolabelled immunoglobulin at the site of infection. Visualization of the infection and the image quality, especially the 6- and 24-h images, were clearly enhanced after the use of immunoglobulin preparations as compared with those labelled with gallium. (orig.)

On numerical simulation of the global distribution of sulfate aerosol produced by a large volcanic eruption

Energy Technology Data Exchange (ETDEWEB)

Pudykiewicz, J.A.; Dastoor, A.P. [Atmospheric Environment Service, Quebec (Canada)

1994-12-31

Volcanic eruptions play an important role in the global sulfur cycle of the Earth`s atmosphere and can significantly perturb the global atmospheric chemistry. The large amount of sulfate aerosol produced by the oxidation of SO{sub 2} injected into the atmosphere during volcanic eruptions also has a relatively big influence on the radiative equilibrium of the Earth`s climatic system. The submicron particles of the sulfate aerosol reflect solar radiation more effectively than they trap radiation in the infrared range. The effect of this is observed as cooling of the Earth`s surface. The modification of the global radiation budget following volcanic eruption can subsequently cause significant fluctuations of atmospheric variables on a subclimatic scale. The resulting perturbation of weather patterns has been observed and well documented since the eruptions of Mt. Krakatau and Mt. Tambora. The impact of the sulfate aerosol from volcanic eruptions on the radiative equilibrium of the Earth`s atmosphere was also confirmed by the studies done with Global Circulation Models designed to simulate climate. The objective of the present paper is to present a simple and effective method to estimate the global distribution of the sulfate aerosol produced as a consequence of volcanic eruptions. In this study we will present results of the simulation of global distribution of sulfate aerosol from the eruption of Mt Pinatubo.

High density submicron magnetoresistive random access memory (invited)

Science.gov (United States)

Tehrani, S.; Chen, E.; Durlam, M.; DeHerrera, M.; Slaughter, J. M.; Shi, J.; Kerszykowski, G.

1999-04-01

Various giant magnetoresistance material structures were patterned and studied for their potential as memory elements. The preferred memory element, based on pseudo-spin valve structures, was designed with two magnetic stacks (NiFeCo/CoFe) of different thickness with Cu as an interlayer. The difference in thickness results in dissimilar switching fields due to the shape anisotropy at deep submicron dimensions. It was found that a lower switching current can be achieved when the bits have a word line that wraps around the bit 1.5 times. Submicron memory elements integrated with complementary metal-oxide-semiconductor (CMOS) transistors maintained their characteristics and no degradation to the CMOS devices was observed. Selectivity between memory elements in high-density arrays was demonstrated.

Current status and future developments in radiolabelled immunoassays

International Nuclear Information System (INIS)

Edwards, R.

1998-01-01

Radioisotopes are used extensively in medical practice and their use in RIA or IRMA usually represent a small proportion of the total. Radiolabelled immunoassays based on 125 I constitute a simple didactic, cost effective and robust technology which is still regarded as the reference method in many clinical applications. The IAEA has implemented many successful programmes using the ''bulk reagent'' approach, involving 68 countries in all the different regions. The main achievements have been in technology transfer with self sufficiency in production for some countries; training of large numbers of staff; quality control and quality assurance schemes; devolution of screening programmes for neonatal congenital hypothryoidism. Alternatives to the use of radioisotopic tracers are constrained by many factors and are often only available in restricted commercial packages. They are often not suitable for technology transfer programmes and often lack any didactic component in addition to a relative high cost. The production of radiolabels using 125 I is both simple and adaptable. In addition expertise in their preparation and purification is widespread even in developing countries. Together with the ease of producing antibodies, the facts have made 125 I-radiolabelled immunoassays ideal for investigative procedures for many research activities (30,31) particularly in the medical context where radioisotopes are commonly used. In conclusion, even a superficial examination of public health statistics for various countries throughout the continents indicates a need for a simple, inexpensive and robust analytical tool. In this light, there is a predicted continuing role for radiolabelled immunoassays. (author)

Online Chemical Characterization of Food-Cooking Organic Aerosols: Implications for Source Apportionment.

Science.gov (United States)

Reyes-Villegas, Ernesto; Bannan, Thomas; Le Breton, Michael; Mehra, Archit; Priestley, Michael; Percival, Carl; Coe, Hugh; Allan, James D

2018-04-11

Food-cooking organic aerosols (COA) are one of the primary sources of submicron particulate matter in urban environments. However, there are still many questions surrounding source apportionment related to instrumentation as well as semivolatile partitioning because COA evolve rapidly in the ambient air, making source apportionment more complex. Online measurements of emissions from cooking different types of food were performed in a laboratory to characterize particles and gases. Aerosol mass spectrometer (AMS) measurements showed that the relative ionization efficiency for OA was higher (1.56-3.06) relative to a typical value of 1.4, concluding that AMS is over-estimating COA and suggesting that previous studies likely over-estimated COA concentrations. Food-cooking mass spectra were generated using AMS, and gas and particle food markers were identified with filter inlets for gases and aerosols-chemical ionization mass spectrometer (CIMS) measurements to be used in future food cooking-source apportionment studies. However, there is a considerable variability in both gas and particle markers, and dilution plays an important role in the particle mass budget, showing the importance of using these markers with caution during receptor modeling. These findings can be used to better understand the chemical composition of COA, and they provides useful information to be used in future source-apportionment studies.

Radiopharmaceutical development of radiolabelled peptides

Energy Technology Data Exchange (ETDEWEB)

Fani, Melpomeni; Maecke, Helmut R. [University Hospital Freiburg, Department of Nuclear Medicine, Freiburg (Germany)

2012-02-15

Receptor targeting with radiolabelled peptides has become very important in nuclear medicine and oncology in the past few years. The overexpression of many peptide receptors in numerous cancers, compared to their relatively low density in physiological organs, represents the molecular basis for in vivo imaging and targeted radionuclide therapy with radiolabelled peptide-based probes. The prototypes are analogs of somatostatin which are routinely used in the clinic. More recent developments include somatostatin analogs with a broader receptor subtype profile or with antagonistic properties. Many other peptide families such as bombesin, cholecystokinin/gastrin, glucagon-like peptide-1 (GLP-1)/exendin, arginine-glycine-aspartic acid (RGD) etc. have been explored during the last few years and quite a number of potential radiolabelled probes have been derived from them. On the other hand, a variety of strategies and optimized protocols for efficient labelling of peptides with clinically relevant radionuclides such as {sup 99m}Tc, M{sup 3+} radiometals ({sup 111}In, {sup 86/90}Y, {sup 177}Lu, {sup 67/68}Ga), {sup 64/67}Cu, {sup 18}F or radioisotopes of iodine have been developed. The labelling approaches include direct labelling, the use of bifunctional chelators or prosthetic groups. The choice of the labelling approach is driven by the nature and the chemical properties of the radionuclide. Additionally, chemical strategies, including modification of the amino acid sequence and introduction of linkers/spacers with different characteristics, have been explored for the improvement of the overall performance of the radiopeptides, e.g. metabolic stability and pharmacokinetics. Herein, we discuss the development of peptides as radiopharmaceuticals starting from the choice of the labelling method and the conditions to the design and optimization of the peptide probe, as well as some recent developments, focusing on a selected list of peptide families, including somatostatin

The processing and fate of antibodies and their radiolabels bound to the surface of tumor cells in vitro: A comparison of nine radiolabels

International Nuclear Information System (INIS)

Shih, L.B.; Thorpe, S.R.; Griffiths, G.L.; Diril, H.; Ong, G.L.; Hansen, H.J.; Goldenberg, D.M.; Mattes, M.J.

1994-01-01

Processing radiolabeled degradation products is the key factor affecting retention of antibodies within the cell. In this study, the authors have analyzed the processing of antibodies labeled in nine different ways. Antibodies were labeled with three different radioisotopes and seven different forms of 125 I. Eight of the radiolabels (except 188 Re) were conjugated to the same antibody, MA103, and tested on the renal carcinoma cell line SK-RC-18 and/or the ovarian carcinoma cell line SK-OV-6. Rhenium conjugation utilized the antibody RS7, the target cell line ME180 and three of the other radiolabels were also tested with this antibody-target cell combination for comparison. Iodine conjugated to antibodies by conventional methods was rapidly released from the cell after antibody catabolism. In contrast, iodinated moieties, such as dilactitol-tyramine and inulin-tyramine were retained within cells four to five times longer. The use of radiolabels that are trapped within cells after antibody catabolism can potentially increase the dose of radiation delivered to the tumor, from the same amount of radioactivity deposited by a factor of four or five. The prolonged retention of 111 In relative to 125 I is not due to deiodination of iodine conjugates, but rather to intracellular retention of catabolic products containing 111 In, perhaps within lysosomes. 45 refs., 4 figs., 1 tab

Continuous measurements at the urban roadside in an Asian megacity by Aerosol Chemical Speciation Monitor (ACSM): particulate matter characteristics during fall and winter seasons in Hong Kong

Science.gov (United States)

Sun, C.; Lee, B. P.; Huang, D.; Jie Li, Y.; Schurman, M. I.; Louie, P. K. K.; Luk, C.; Chan, C. K.

2016-02-01

Non-refractory submicron aerosol is characterized using an Aerosol Chemical Speciation Monitor (ACSM) in the fall and winter seasons of 2013 on the roadside in an Asian megacity environment in Hong Kong. Organic aerosol (OA), characterized by application of Positive Matrix Factorization (PMF), and sulfate are found to be dominant. Traffic-related organic aerosol shows good correlation with other vehicle-related species, and cooking aerosol displays clear mealtime concentration maxima and association with surface winds from restaurant areas. Contributions of individual species and OA factors to high NR-PM1 are analyzed for hourly data and daily data; while cooking emissions in OA contribute to high hourly concentrations, particularly during mealtimes, secondary organic aerosol components are responsible for episodic events and high day-to-day PM concentrations. Clean periods are either associated with precipitation, which reduces secondary OA with a lesser impact on primary organics, or clean oceanic air masses with reduced long-range transport and better dilution of local pollution. Haze events are connected with increases in contribution of secondary organic aerosol, from 30 to 50 % among total non-refractory organics, and the influence of continental air masses.

Continuous measurements at the urban roadside in an Asian megacity by Aerosol Chemical Speciation Monitor (ACSM: particulate matter characteristics during fall and winter seasons in Hong Kong

Directory of Open Access Journals (Sweden)

C. Sun

2016-02-01

Full Text Available Non-refractory submicron aerosol is characterized using an Aerosol Chemical Speciation Monitor (ACSM in the fall and winter seasons of 2013 on the roadside in an Asian megacity environment in Hong Kong. Organic aerosol (OA, characterized by application of Positive Matrix Factorization (PMF, and sulfate are found to be dominant. Traffic-related organic aerosol shows good correlation with other vehicle-related species, and cooking aerosol displays clear mealtime concentration maxima and association with surface winds from restaurant areas. Contributions of individual species and OA factors to high NR-PM1 are analyzed for hourly data and daily data; while cooking emissions in OA contribute to high hourly concentrations, particularly during mealtimes, secondary organic aerosol components are responsible for episodic events and high day-to-day PM concentrations. Clean periods are either associated with precipitation, which reduces secondary OA with a lesser impact on primary organics, or clean oceanic air masses with reduced long-range transport and better dilution of local pollution. Haze events are connected with increases in contribution of secondary organic aerosol, from 30 to 50 % among total non-refractory organics, and the influence of continental air masses.

Novel strategies for microdose studies using non-radiolabeled compounds.

Science.gov (United States)

Maeda, Kazuya; Sugiyama, Yuichi

2011-06-19

Microdose studies using non-radiolabeled compounds enable assessment of the clinical pharmacokinetics of drug candidates in humans without the need to synthesize radiolabeled compounds. We have demonstrated that the quantification limits of many drugs measured by LC-MS/MS are low enough to allow estimation of their pharmacokinetic parameters following administration of a microdose. Our previous microdose studies with LC-MS/MS demonstrated the linear pharmacokinetics of fexofenadine between microdoses and therapeutic doses. We also obtained time profiles of plasma concentrations of nicardipine and its multiple metabolites following administration of a microdose. A significant advantage of using non-radiolabeled compounds is the ability to perform cassette microdose studies. By administering multiple drug candidates to the same subject, we can select compounds with appropriate pharmacokinetic properties simultaneously. We can also clarify major factors dominating the pharmacokinetics of drug candidates by cocktail microdosing of the test compounds and probe substrates with or without specific inhibitors for enzymes/transporters. Copyright © 2011 Elsevier B.V. All rights reserved.

Aerosol chemical composition at Cabauw, The Netherlands as observed in two intensive periods in May 2008 and March 2009

Science.gov (United States)

Mensah, A. A.; Holzinger, R.; Otjes, R.; Trimborn, A.; Mentel, Th. F.; ten Brink, H.; Henzing, B.; Kiendler-Scharr, A.

2012-05-01

Observations of aerosol chemical composition in Cabauw, the Netherlands, are presented for two intensive measurement periods in May 2008 and March 2009. Sub-micron aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS) and is compared to observations from aerosol size distribution measurements as well as composition measurements with a Monitor for AeRosol and GAses (MARGA) based instrument and a Thermal-Desorption Proton-Transfer-Reaction Mass-Spectrometer (TD-PTR-MS). An overview of the data is presented and the data quality is discussed. In May 2008 enhanced pollution was observed with organics contributing 40% to the PM1 mass. In contrast the observed average mass loading was lower in March 2009 and a dominance of ammonium nitrate (42%) was observed. The semi-volatile nature of ammonium nitrate is evident in the diurnal cycles with maximum concentrations observed in the morning hours in May 2008 and little diurnal variation observed in March 2009. Size dependent composition data from AMS measurements are presented and show a dominance of organics in the size range below 200 nm. A higher O:C ratio of the organics is observed for May 2008 than for March 2009. Together with the time series of individual tracer ions this shows the dominance of OOA over HOA in May 2008.

Assessment of radioactive residues arising from radiolabel instability in a multiple dose tissue distribution study in rats

International Nuclear Information System (INIS)

Slatter, J.G.; Sams, J.P.; Easter, J.A.

2003-01-01

Our study objectives were to quantitatively determine the effect of radiolabel instability on terminal phase radioactive tissue residues in a multiple dose tissue distribution study, to quantitatively compare tissue residue artifacts (non drug-related radioactivity) from two chemically-distinct radiolabel locations, and to conduct a definitive multiple dose tissue distribution study using the better of the two radiolabeled compounds. We compared the excretion and tissue distribution in rats of [ 14 C]linezolid, radiolabeled in two different locations, after 7 consecutive once daily [ 14 C] oral doses. The radiolabels were in the acetamide (two carbon) and oxazolidinone (isolated carbon) functional groups. Terminal phase tissue residue and excretion data were compared to data from rats dosed orally with [ 14 C]sodium acetate. Drug-related radioactivity was excreted rapidly over 24 h. After a single dose, the acetamide and oxazolidinone radiolabel sites both gave 3% of dose as exhaled 14 CO 2 . After 7 daily [ 14 C] oral doses, terminal phase radioactive tissue residues were higher from the acetamide radiolabel, relative to the oxazolidinone radiolabel, and were primarily not drug-related. In the definitive tissue distribution study, low concentrations of drug-related radioactivity in skin and thyroid were observed. We conclude that although small amounts of radiolabel instability do not significantly affect single dose tissue radioactivity C max and area under the curve (AUC), artifacts arising from radiolabel instability can prolong the apparent terminal phase half life and complicate study data interpretation. When possible, it is always preferable to use a completely stable radiolabel site. (author)

Assessment of radioactive residues arising from radiolabel instability in a multiple dose tissue distribution study in rats

Energy Technology Data Exchange (ETDEWEB)

Slatter, J.G. [Pharmacia Corp., Peapack, NJ (United States); Sams, J.P.; Easter, J.A. [Pharmacia Corp., Kalamazoo, MI (United States)] [and others

2003-05-01

Our study objectives were to quantitatively determine the effect of radiolabel instability on terminal phase radioactive tissue residues in a multiple dose tissue distribution study, to quantitatively compare tissue residue artifacts (non drug-related radioactivity) from two chemically-distinct radiolabel locations, and to conduct a definitive multiple dose tissue distribution study using the better of the two radiolabeled compounds. We compared the excretion and tissue distribution in rats of [{sup 14}C]linezolid, radiolabeled in two different locations, after 7 consecutive once daily [{sup 14}C] oral doses. The radiolabels were in the acetamide (two carbon) and oxazolidinone (isolated carbon) functional groups. Terminal phase tissue residue and excretion data were compared to data from rats dosed orally with [{sup 14}C]sodium acetate. Drug-related radioactivity was excreted rapidly over 24 h. After a single dose, the acetamide and oxazolidinone radiolabel sites both gave 3% of dose as exhaled {sup 14}CO{sub 2}. After 7 daily [{sup 14}C] oral doses, terminal phase radioactive tissue residues were higher from the acetamide radiolabel, relative to the oxazolidinone radiolabel, and were primarily not drug-related. In the definitive tissue distribution study, low concentrations of drug-related radioactivity in skin and thyroid were observed. We conclude that although small amounts of radiolabel instability do not significantly affect single dose tissue radioactivity C{sub max} and area under the curve (AUC), artifacts arising from radiolabel instability can prolong the apparent terminal phase half life and complicate study data interpretation. When possible, it is always preferable to use a completely stable radiolabel site. (author)

Partition of radiolabeled amino acids in detached wheat heads in culture

International Nuclear Information System (INIS)

Inwood, W.; Bernardin, J.

1990-01-01

The concentration of a particular amino acid supplied to a detached wheat head affected the ultimate distribution of that amino acid among the tissues of the head. Detached wheat heads (Triticum aestivum L. cv Cheyenne) were supplied with a pulse of [ 3 H]leucine in the culture medium and were chased with medium that contained glutamine as the sole nitrogen source. When the amount of radiolabel was held constant, an increasing concentration of unlabeled leucine in the pulse medium led to an increased partition of the radiolabel into the grain tissues of the head. When the concentration of unlabeled leucine was increased from zero to radiolabeled leucine was partitioned to endosperm tissue and twice as much to seedcoat tissues. An effect of amino acid concentration on radiolabel partition was also found for methionine and proline, but the effect was not as dramatic. These results suggest the existence of an amino acid transport system between the transpiration stream of the wheat head and the grain that exhibits cooperative kinetics or amino acid activation

Pharmacokinetics and biodistribution of radiolabeled avidin, streptavidin and biotin

International Nuclear Information System (INIS)

Rosebrough, S.F.

1993-01-01

The extraordinarily high affinity of avidin and streptavidin for biotin may be exploited in a two-step approach for delivering radiolabeled biotin derivatives suitable for imaging and therapy to target-bound streptavidin or avidin conjugated monoclonal antibodies (MAbs). The in vivo pharmacokinetics and biodistribution of radiolabeled avidin, streptavidin (SA) and DTPA-biocytinamide (DTPA-biotin) were studied in the rabbit and dog. SA circulated in the blood similar to other 60 kDa proteins, avidin cleared immediately and DTPA-biotin exhibited plasma clearance by glomerular filtration. (author)

Advances in infectious foci imaging using 99mTc radiolabelled antibiotics

International Nuclear Information System (INIS)

Seyedeh Fatemeh Mirshojaei

2015-01-01

Conventional methods of infection diagnosis, relying on experimental tests and culture of organisms from infected foci have continued to developing new technologies and automation. Nuclear medicine is a reliable diagnostic technique capable to detect infectious foci in human disease. A wide range of radiolabeled agents have been evaluated for demonstrating their ability to distinguish microbial infectious lesions. New researches continue to be made on the use of radiolabeled antibiotics which as well as being highly specific in the diagnosis of infection would be useful in monitoring of disease treatment. Here, the new approaches of infection scintigraphic imaging by radiolabeled antibiotics are thoroughly discussed in order to assess and compare their diagnostic value as targeting imaging radiopharmaceuticals. (author)

Synthesis of 14C-radiolabelled Tilmicosin

International Nuclear Information System (INIS)

Crouse, G.D.; Terando, N.H.

1989-01-01

Tilmicosin was radiolabelled with carbon-14 on the 3,5-dimethylpiperidinyl sidechain as a requirement for animal metabolism studies. A new radiosynthesis of 3,5-dimethyl-piperidine was developed for this purpose. Incorporation into the desmycosin nucleus was accomplished by a reductive amination reaction. (author)

Radiolabeling of biological vectors by poly-aza-macrocyclic complexes

International Nuclear Information System (INIS)

Moreau, M.

2012-01-01

This work conducted at the 'Institut de Chimie Moleculaire de l'Universite de Bourgogne' carries at first on the synthesis of bifunctional chelating agents suitable for the chelation of trivalent radio-metals, including indium-111. The greater part of this work was then dedicated to the grafting of a DOTA derivative bifunctional chelating agent on different antibodies or fragments of monoclonal antibodies: trastuzumab (anti-HER2 treatment of breast cancer), cetuximab (anti EGFR, treatment of many cancers, including colorectal cancer) and abciximab (antiplatelet). Particular attention was paid to the characterization of various immuno-conjugates. The critical step of this thesis consisted in the indium-111 radiolabeling of two previously prepared immuno-conjugates: trastuzumab and cetuximab. These steps of radiolabelling allowed us to determine the immunoreactive fraction and affinity of each radiotracer. Thus, we were able to study the in vivo biodistribution of the radiotracers in tumour-bearing mice by SPECT-CT. We also developed an original method for the labeling of a Fab antibody fragment in order to monitor the biodistribution of the antiplatelet agent (abciximab). Finally, we also validated the concept of multimodal imaging through grafting and radiolabeling of a bimodal agent for optical and SPECT imaging on bacterial lipopolysaccharide. Thanks to this work, we gained an expertise in antibodies radiolabeling. The results obtained allow to consider the labeling of antibodies or other biomolecules, and the use of other radionuclides for PET imaging and radioimmunotherapy. (author)

Characterization of aerosol pollution events in France using ground-based and POLDER-2 satellite data

Directory of Open Access Journals (Sweden)

M. Kacenelenbogen

2006-01-01

Full Text Available We analyze the relationship between daily fine particle mass concentration (PM2.5 and columnar aerosol optical thickness derived from the Polarization and Directionality of Earth's Reflectances (POLDER satellite sensor. The study is focused over France during the POLDER-2 lifetime between April and October 2003. We have first compared the POLDER derived aerosol optical thickness (AOT with integrated volume size distribution derived from ground-based Sun Photometer observations. The good correlation (R=0.72 with sub-micron volume fraction indicates that POLDER derived AOT is sensitive to the fine aerosol mass concentration. Considering 1974 match-up data points over 28 fine particle monitoring sites, the POLDER-2 derived AOT is fairly well correlated with collocated PM2.5 measurements, with a correlation coefficient of 0.55. The correlation coefficient reaches a maximum of 0.80 for particular sites. We have analyzed the probability to find an appropriate air quality category (AQC as defined by U.S. Environmental Protection Agency (EPA from POLDER-2 AOT measurements. The probability can be up to 88.8% (±3.7% for the "Good" AQC and 89.1% (±3.6% for the "Moderate" AQC.

Heterogeneous Uptake of HO2 Radicals onto Atmospheric Aerosols

Science.gov (United States)

George, I. J.; Matthews, P. S.; Brooks, B.; Goddard, A.; Whalley, L. K.; Baeza-Romero, M. T.; Heard, D. E.

2011-12-01

The hydroxyl (OH) and hydroperoxyl (HO2) radicals, together known as HOx, play a vital role in atmospheric chemistry by controlling the oxidative capacity of the troposphere. The atmospheric lifetime and concentrations of many trace reactive species, such as volatile organic compounds (VOCs), are determined by HOx radical levels. Therefore, the ability to accurately predict atmospheric HOx concentrations from a detailed knowledge of their sources and sinks is a very useful diagnostic tool to assess our current understanding of atmospheric chemistry. Several recent field studies have observed significantly lower concentrations of HO2 radicals than predicted using box models, where HO2 loss onto aerosols was suggested as a possible missing sink [1, 2]. However, the mechanism on HO2 uptake onto aerosols and its impact on ambient HOx levels are currently not well understood. To improve our understanding of this process, we have conducted laboratory experiments to measure HO2 uptake coefficients onto submicron aerosol particles. The FAGE (Fluorescence Assay by Gas Expansion) technique, a highly sensitive laser induced fluorescence based detection method, was used to monitor HO2 uptake kinetics onto aerosol particles in an aerosol flow tube. The application of the FAGE technique allowed for kinetic experiments to be performed under low HO2 concentrations, i.e. [HO2] atomizing dilute salt solutions or by homogeneous nucleation. HO2 uptake coefficients (γ) have been measured for single-component solid and aqueous inorganic salt and organic aerosol particles with a wide range of hygroscopicities. HO2 uptake coefficients on solid particles were below the detection limit (γ < 0.001), whereas on aqueous aerosols uptake coefficients were somewhat larger (γ = 0.001 - 0.008). HO2 uptake coefficients were highest on aerosols containing metal ions, such as Cu and Fe. Humidity and aerosol pH did not significantly impact the reactive HO2 uptake. Preliminary experiments have also

Characterization and source apportionment of organic aerosol at 260 m on a meteorological tower in Beijing, China

Directory of Open Access Journals (Sweden)

W. Zhou

2018-03-01

Full Text Available Despite extensive efforts toward the characterization of submicron aerosols at ground level in the megacity of Beijing, our understanding of aerosol sources and processes at high altitudes remains low. Here we conducted a 3-month real-time measurement of non-refractory submicron aerosol (NR-PM1 species at a height of 260 m from 10 October 2014 to 18 January 2015 using an aerosol chemical speciation monitor. Our results showed a significant change in aerosol composition from the non-heating period (NHP to the heating period (HP. Organics and chloride showed clear increases during HP due to coal combustion emissions, while nitrate showed substantial decreases from 28 to 15–18 %. We also found that NR-PM1 species in the heating season can have average mass differences of 30–44 % under similar emission sources yet different meteorological conditions. Multi-linear engine 2 (ME-2 using three primary organic aerosol (OA factors as constraints, i.e., fossil-fuel-related OA (FFOA dominantly from coal combustion emissions, cooking OA (COA, and biomass burning OA (BBOA resolved from ground high-resolution aerosol mass spectrometer measurements, was applied to OA mass spectra of ACSM. Two types of secondary OA (SOA that were well correlated with nitrate and chloride–CO, respectively, were identified. SOA played a dominant role in OA during all periods at 260 m although the contributions were decreased from 72 % during NHP to 58–64 % during HP. The SOA composition also changed significantly from NHP to HP. While the contribution of oxygenated OA (OOA was decreased from 56–63 to 32–40 %, less oxidized OOA (LO-OOA showed a large increase from 9–16 to 24–26 %. COA contributed a considerable fraction of OA at high altitude, and the contribution was relatively similar across different periods (10–13 %. In contrast, FFOA showed a large increase during HP due to the influences of coal combustion emissions. We also

High Proportions of Sub-micron Particulate Matter in Icelandic Dust Storms in 2015

Science.gov (United States)

Dagsson Waldhauserova, Pavla; Arnalds, Olafur; Olafsson, Haraldur; Magnusdottir, Agnes

2017-04-01

Iceland is extremely active dust region and desert areas of over 44,000 km2 acknowledge Iceland as the largest Arctic and European desert. Frequent dust events, up to 135 dust days annually, transport dust particles far distances towards the Arctic and Europe. Satellite MODIS pictures have revealed dust plumes exceeding 1,000 km. The annual dust deposition was calculated as 40.1 million tons yr-1. Two dust storms were measured in transverse horizontal profile about 90 km far from different dust sources in southwestern Iceland in the summer of 2015. Aerosol monitor DustTrak DRX 8533EP was used to measure PM mass concentrations corresponding to PM1, PM2.5, PM4, PM10 and the total PM15 at several places within the dust plume. Images from camera network operated by the Icelandic Road and Coastal Administration were used to estimate the visibility and spatial extent of measured dust events. A numerical simulation of surface winds was carried out with the numerical model HIRLAM with horizontal resolution of 5 km and used to calculate the total dust flux from the sources. The in situ measurements inside the dust plumes showed that aeolian dust can be very fine. The study highlights that suspended volcanic dust in Iceland causes air pollution with extremely high PM1 concentrations comparable to the polluted urban stations in Europe or Asia rather than reported dust event observations from around the world. The PM1/PM2.5 ratios are generally low during dust storms outside of Iceland, much lower than > 0.9 and PM1/PM10 ratios of 0.34-0.63 found in our study. It shows that Icelandic volcanic dust consists of higher proportion of submicron particles compared to crustal dust. The submicron particles are predicted to travel long distances. Moreover, such submicron particles pose considerable health risk because of high potential for entering the lungs. Icelandic volcanic glass has often fine pipe-vesicular structures known from asbestos and high content of heavy metals. Previous

Chemical radiolabeling of carboxyatractyloside by [14C]acetic anhydride

International Nuclear Information System (INIS)

Block, M.R.; Pougeois, R.; Vignais, P.V.

1980-01-01

The authors report the synthesis and biological properties of a radiolabeled derivative of CAT obtained with acetylation of the primary alcohol of CAT with radiolabeled acetic anhydride. They also investigate the question of mutual exclusion of CAT and BA for binding to the mitochondrial ADP/ATP carrier in double labeling experiments based on the use of [ 3 H]BA and [ 14 C]Ac-CAT. The results are consistent with the view that the ADP/ATP carrier possesses two separate interacting binding sites for AT (or CAT) and for BA. (Auth.)

An Efficient and Straightforward Method for Radiolabeling of Nanoparticles with {sup 64}Cu via Click Chemistry

Energy Technology Data Exchange (ETDEWEB)

Lee, Dong-Eun [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Kim, Kwangmeyung [Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 136-791 (Korea, Republic of); Park, Sang Hyun [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Department of Radiobiotechnology and Applied Radioisotope Science, Korea University of Science and Technology, Deajeon 305-350 (Korea, Republic of)

2015-07-01

Recently, nanoparticles have received a great deal of interest in diagnosis and therapy applications. Since nanoparticles possess intrinsic features that are often required for a drug delivery system and diagnosis, they have potential to be used as platforms for integrating imaging and therapeutic functions, simultaneously. Intrinsic issues that are associated with theranostic nanoparticles, particularly in cancer treatment, include an efficient and straightforward radiolabeling method for understanding the in vivo biodistribution of nanoparticles to reach the tumor region, and monitoring therapeutic responses. Herein, we investigated a facile and highly efficient strategy to prepare radiolabeled nanoparticles with {sup 64}Cu via a strain-promoted azide, i.e., an alkyne cycloaddition strategy, which is often referred to as click chemistry. First, the azide (N3) group, which allows for the preparation of radiolabeled nanoparticles by copper-free click chemistry, was incorporated into glycol chitosan nanoparticles (CNPs). Second, the strained cyclooctyne derivative, dibenzyl cyclooctyne (DBCO) conjugated with a 1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid (DOTA) chelator, was synthesized for preparing the pre-radiolabeled alkyne complex with {sup 64}Cu radionuclide. Following incubation with the {sup 64}Cu-radiolabeled DBCO complex (DBCO-PEG4-Lys-DOTA-{sup 64}Cu with high specific activity, 18.5 GBq/μ mol), the azide-functionalized CNPs were radiolabeled successfully with {sup 64}Cu, with a high radiolabeling efficiency and a high radiolabeling yield (>98%). Importantly, the radiolabeling of CNPs by copper-free click chemistry was accomplished within 30 min, with great efficiency in aqueous conditions. After {sup 64}Cu-CNPs were intravenously administered to tumor-bearing mice, the real time, in vivo biodistribution and tumor-targeting ability of {sup 64}Cu-CNPs were quantitatively evaluated by micro-PET images of tumor-bearing mice. These results

SUBMICRON PARTICLES EMISSION CONTROL BY ELECTROSTATIC AGGLOMERATION

Directory of Open Access Journals (Sweden)

Andrzej Krupa

2017-04-01

Full Text Available The aim of the study was to develop a device for more effective treatment of flue gases from submicron particles emitted by power plants burning bituminous coal and by this way the reduction of environment pollution. Electrostatic processes were employed to this goal, as the most effective solution. The solutions hitherto applied in electrostatic precipitation techniques were designed for large particles, typically with sizes> 5 µm, which are easily removed by the action of electrostatic force on the electrically charged particles. In submicron size range (0.1-1 µm the collection efficiency of an ESP is minimal, because of the low value of electric charge on such particles. In order to avoid problems with the removal of submicron particles of fly ash from the flue gases electrostatic agglomeration has been used. In this process, by applying an alternating electric field, larger charged particles (> 1 µm oscillate, and the particles "collect" smaller uncharged particles. In the developed agglomerator with alternating electric field, the charging of particles and the coagulation takes place in one stage that greatly simplified the construction of the device, compared to other solutions. The scope of this study included measurements of fractional collection efficiency of particles in the system comprising of agglomerator and ESP for PM1 and PM2.5 ranges, in device made in pilot scale. The collection efficiency for PM2.5 was greater than 90% and PM1 slightly dropped below 90%. The mass collection efficiency for PM2.5 was greater than 95%. The agglomerator stage increases the collection efficiency for PM1 at a level of 5-10%.

Aerosol processing: a wind of innovation in the field of advanced heterogeneous catalysts.

Science.gov (United States)

Debecker, Damien P; Le Bras, Solène; Boissière, Cédric; Chaumonnot, Alexandra; Sanchez, Clément

2018-04-16

Aerosol processing is long known and implemented industrially to obtain various types of divided materials and nanomaterials. The atomisation of a liquid solution or suspension produces a mist of aerosol droplets which can then be transformed via a diversity of processes including spray-drying, spray pyrolysis, flame spray pyrolysis, thermal decomposition, micronisation, gas atomisation, etc. The attractive technical features of these aerosol processes make them highly interesting for the continuous, large scale, and tailored production of heterogeneous catalysts. Indeed, during aerosol processing, each liquid droplet undergoes well-controlled physical and chemical transformations, allowing for example to dry and aggregate pre-existing solid particles or to synthesise new micro- or nanoparticles from mixtures of molecular or colloidal precursors. In the last two decades, more advanced reactive aerosol processes have emerged as innovative means to synthesise tailored-made nanomaterials with tunable surface properties, textures, compositions, etc. In particular, the "aerosol-assisted sol-gel" process (AASG) has demonstrated tremendous potential for the preparation of high-performance heterogeneous catalysts. The method is mainly based on the low-cost, scalable, and environmentally benign sol-gel chemistry process, often coupled with the evaporation-induced self-assembly (EISA) concept. It allows producing micronic or submicronic, inorganic or hybrid organic-inorganic particles bearing tuneable and calibrated porous structures at different scales. In addition, pre-formed nanoparticles can be easily incorporated or formed in a "one-pot" bottom-up approach within the porous inorganic or hybrid spheres produced by such spray drying method. Thus, multifunctional catalysts with tailored catalytic activities can be prepared in a relatively simple way. This account is an overview of aerosol processed heterogeneous catalysts which demonstrated interesting performance in

Electron beam fabrication of a microfluidic device for studying submicron-scale bacteria

Science.gov (United States)

2013-01-01

Background Controlled restriction of cellular movement using microfluidics allows one to study individual cells to gain insight into aspects of their physiology and behaviour. For example, the use of micron-sized growth channels that confine individual Escherichia coli has yielded novel insights into cell growth and death. To extend this approach to other species of bacteria, many of whom have dimensions in the sub-micron range, or to a larger range of growth conditions, a readily-fabricated device containing sub-micron features is required. Results Here we detail the fabrication of a versatile device with growth channels whose widths range from 0.3 μm to 0.8 μm. The device is fabricated using electron beam lithography, which provides excellent control over the shape and size of different growth channels and facilitates the rapid-prototyping of new designs. Features are successfully transferred first into silicon, and subsequently into the polydimethylsiloxane that forms the basis of the working microfluidic device. We demonstrate that the growth of sub-micron scale bacteria such as Lactococcus lactis or Escherichia coli cultured in minimal medium can be followed in such a device over several generations. Conclusions We have presented a detailed protocol based on electron beam fabrication together with specific dry etching procedures for the fabrication of a microfluidic device suited to study submicron-sized bacteria. We have demonstrated that both Gram-positive and Gram-negative bacteria can be successfully loaded and imaged over a number of generations in this device. Similar devices could potentially be used to study other submicron-sized organisms under conditions in which the height and shape of the growth channels are crucial to the experimental design. PMID:23575419

Radiolabeled monoclonal antibodies for imaging and therapy: Potential, problems, and prospects: Scientific highlights

International Nuclear Information System (INIS)

Srivastava, S.C.; Buraggi, G.L.

1986-01-01

This meeting focused on areas of research on radiolabeled monoclonal antibodies. Topics covered included the production, purification, and fragmentation of monoclonal antibodies and immunochemistry of hybridomas; the production and the chemistry of radionuclides; the radiohalogenation and radiometal labeling techniques; the in-vivo pharmacokinetics of radiolabeled antibodies; the considerations of immunoreactivity of radiolabeled preparations; the instrumentation and imaging techniques as applied to radioimmunodetection; the radiation dosimetry in diagnostic and therapeutic use of labeled antibodies; the radioimmunoscintigraphy and radioimmunotherapy studies; and perspectives and directions for future research. Tutorial as well as scientific lectures describing the latest research data on the above topics were presented. Three workshop panels were convened on ''Methods for Determining Immunoreactivity of Radiolabeled Monoclonal Antibodies - Problems and Pitfalls,'' Radiobiological and Dosimetric Considerations for Immunotherapy with Labeled Antibodies,'' and ''The Human Anti-Mouse Antibody Response in Patients.''

Long-circulating liposomes radiolabeled with [18F]fluorodipalmitin ([18F]FDP)

International Nuclear Information System (INIS)

Marik, Jan; Tartis, Michaelann S.; Zhang, Hua; Fung, Jennifer Y.; Kheirolomoom, Azadeh; Sutcliffe, Julie L.; Ferrara, Katherine W.

2007-01-01

Synthesis of a radiolabeled diglyceride, 3-[ 18 F]fluoro-1,2-dipalmitoylglycerol [[ 18 F]fluorodipalmitin ([ 18 F]FDP)], and its potential as a reagent for radiolabeling long-circulating liposomes were investigated. The incorporation of 18 F into the lipid molecule was accomplished by nucleophilic substitution of the p-toluenesulfonyl moiety with a decay-corrected yield of 43±10% (n=12). Radiolabeled, long-circulating polyethylene-glycol-coated liposomes were prepared using a mixture of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, cholesterol, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N- [methoxy(polyethyleneglycol)-2000] ammonium salt (61:30:9) and [ 18 F]FDP with a decay-corrected yield of 70±8% (n=4). PET imaging and biodistribution studies were performed with free [ 18 F]FDP and liposome-incorporated [ 18 F]FDP. Freely injected [ 18 F]FDP had the highest uptake in the liver, spleen and lungs. Liposomal [ 18 F]FDP remained in blood circulation at near-constant levels for at least 90 min, with a peak concentration near 2.5%ID/cc. Since [ 18 F]FDP was incorporated into the phospholipid bilayer, it could potentially be used for radiolabeling a variety of lipid-based drug carriers

Lymphoma: current status of clinical and preclinical imaging with radiolabeled antibodies

Energy Technology Data Exchange (ETDEWEB)

England, Christopher G. [University of Wisconsin School of Medicine and Public Health, Department of Medical Physics, Madison, WI (United States); Rui, Lixin [University of Wisconsin School of Medicine and Public Health, Department of Medicine, Madison, WI (United States); University of Wisconsin School of Medicine and Public Health, Carbone Cancer Center, Madison, WI (United States); Cai, Weibo [University of Wisconsin School of Medicine and Public Health, Department of Medical Physics, Madison, WI (United States); University of Wisconsin School of Medicine and Public Health, Carbone Cancer Center, Madison, WI (United States); University of Wisconsin School of Medicine and Public Health, Department of Radiology, Madison, WI (United States)

2017-03-15

Lymphoma is a complex disease that arises from cells of the immune system with an intricate pathology. While lymphoma may be classified as Hodgkin or non-Hodgkin, each type of tumor is genetically and phenotypically different and highly invasive tissue biopsies are the only method to investigate these differences. Noninvasive imaging strategies, such as immunoPET, can provide a vital insight into disease staging, monitoring treatment response in patients, and dose planning in radioimmunotherapy. ImmunoPET imaging with radiolabeled antibody-based tracers may also assist physicians in optimizing treatment strategies and enhancing patient stratification. Currently, there are two common biomarkers for molecular imaging of lymphoma, CD20 and CD30, both of which have been considered for investigation in preclinical imaging studies. In this review, we examine the current status of both preclinical and clinical imaging of lymphoma using radiolabeled antibodies. Additionally, we briefly investigate the role of radiolabeled antibodies in lymphoma therapy. As radiolabeled antibodies play critical roles in both imaging and therapy of lymphoma, the development of novel antibodies and the discovery of new biomarkers may greatly affect lymphoma imaging and therapy in the future. (orig.)

Lymphoma: current status of clinical and preclinical imaging with radiolabeled antibodies

International Nuclear Information System (INIS)

England, Christopher G.; Rui, Lixin; Cai, Weibo

2017-01-01

Lymphoma is a complex disease that arises from cells of the immune system with an intricate pathology. While lymphoma may be classified as Hodgkin or non-Hodgkin, each type of tumor is genetically and phenotypically different and highly invasive tissue biopsies are the only method to investigate these differences. Noninvasive imaging strategies, such as immunoPET, can provide a vital insight into disease staging, monitoring treatment response in patients, and dose planning in radioimmunotherapy. ImmunoPET imaging with radiolabeled antibody-based tracers may also assist physicians in optimizing treatment strategies and enhancing patient stratification. Currently, there are two common biomarkers for molecular imaging of lymphoma, CD20 and CD30, both of which have been considered for investigation in preclinical imaging studies. In this review, we examine the current status of both preclinical and clinical imaging of lymphoma using radiolabeled antibodies. Additionally, we briefly investigate the role of radiolabeled antibodies in lymphoma therapy. As radiolabeled antibodies play critical roles in both imaging and therapy of lymphoma, the development of novel antibodies and the discovery of new biomarkers may greatly affect lymphoma imaging and therapy in the future. (orig.)

Evidence for a significant proportion of Secondary Organic Aerosol from isoprene above a maritime tropical forest

Directory of Open Access Journals (Sweden)

N. H. Robinson

2011-02-01

Full Text Available Isoprene is the most abundant non-methane biogenic volatile organic compound (BVOC, but the processes governing secondary organic aerosol (SOA formation from isoprene oxidation are only beginning to become understood and selective quantification of the atmospheric particulate burden remains difficult. Organic aerosol above a tropical rainforest located in Danum Valley, Borneo, Malaysia, a high isoprene emission region, was studied during Summer 2008 using Aerosol Mass Spectrometry and offline detailed characterisation using comprehensive two dimensional gas chromatography. Observations indicate that a substantial fraction (up to 15% by mass of atmospheric sub-micron organic aerosol was observed as methylfuran (MF after thermal desorption. This observation was associated with the simultaneous measurements of established gas-phase isoprene oxidation products methylvinylketone (MVK and methacrolein (MACR. Observations of MF were also made during experimental chamber oxidation of isoprene. Positive matrix factorisation of the AMS organic mass spectral time series produced a robust factor which accounts for an average of 23% (0.18 μg m⁻³, reaching as much as 53% (0.50 μg m⁻³ of the total oraganic loading, identified by (and highly correlated with a strong MF signal. Assuming that this factor is generally representative of isoprene SOA, isoprene derived aerosol plays a significant role in the region. Comparisons with measurements from other studies suggest this type of isoprene SOA plays a role in other isoprene dominated environments, albeit with varying significance.

Radiolabelling of autologous leucocytes: technique and clinical application

International Nuclear Information System (INIS)

Strobl-Jaeger, E.; Kolbe, H.; Ludwig, H.; Sinzinger, H.

1988-01-01

Gamma-camera imaging after injection of radiolabelled autologous leucocytes can be very helpful in the diagnosis, localization and further clinical treatment of inflammatory diseases. We present a technique allowing sterile separation of white blood cells and labelling with 99m Tc-phytate or -oxine and with 111 In-oxine, -oxine sulphate or -tropolone. The method is non-invasive and the radiation dose amounts to less than 80 mrad using 100 μCi 111 Indium. The use of radiolabelled granulocytes is of particular diagnostic value in patients with septicaemia of unknown origin. Whole body scanning allows not only visualization of enhanced splenic uptake in septicaemia, but also localization of an inflammatory process. Preferential indications for a diagnostic approach using radiolabelled granulocytes are inflammatory abdominal processes which cannot easily be documented by means of other non-invasive techniques, such as inflammatory bowel disease (Crohn's diseases and ulcerative colitis), arthritic processes and abscesses of the liver and spleen, as well as subphrenic and retroperitoneal abscesses. Untreated osteomyelitis can be located with the help of labelled granulocytes, but in patients treated with antibiotics a false negative result is obtained in approximately 50 % of cases for as yet unknown reasons, even in the presence of a still active osteomyelitic process. (Authors)

Aerosol source apportionment from 1-year measurements at the CESAR tower in Cabauw, the Netherlands

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P. Schlag

2016-07-01

Full Text Available Intensive measurements of submicron aerosol particles and their chemical composition were performed with an Aerosol Chemical Speciation Monitor (ACSM at the Cabauw Experimental Site for Atmospheric Research (CESAR in Cabauw, the Netherlands, sampling at 5 m height above ground. The campaign lasted nearly 1 year from July 2012 to June 2013 as part of the EU-FP7-ACTRIS project (Q-ACSM Network. Including equivalent black carbon an average particulate mass concentration of 9.50 µg m−3 was obtained during the whole campaign with dominant contributions from ammonium nitrate (45 %, organic aerosol (OA, 29 %, and ammonium sulfate (19 %. There were 12 exceedances of the World Health Organization (WHO PM2.5 daily mean limit (25 µg m−3 observed at this rural site using PM1 instrumentation only. Ammonium nitrate and OA represented the largest contributors to total particulate matter during periods of exceedance. Source apportionment of OA was performed season-wise by positive matrix factorization (PMF using the multilinear engine 2 (ME-2 controlled via the source finder (SoFi. Primary organic aerosols were attributed mainly to traffic (8–16 % contribution to total OA, averaged season-wise and biomass burning (0–23 %. Secondary organic aerosols (SOAs, 61–84 % dominated the organic fraction during the whole campaign, particularly on days with high mass loadings. A SOA factor which is attributed to humic-like substances (HULIS was identified as a highly oxidized background aerosol in Cabauw. This shows the importance of atmospheric aging processes for aerosol concentration at this rural site. Due to the large secondary fraction, the reduction of particulate mass at this rural site is challenging on a local scale.

Radiolabelled blood elements techniques and clinical applications

International Nuclear Information System (INIS)

Thakur, M.L.

1992-01-01

Over the past few years, in nuclear medicine, the diagnostic applications of radiolabelled blood elements in general, and of radiolabelled white blood cells in particular, have become increasingly popular. This is primarily due to the introduction of lipid soluble 111 In-oxine as an agent, which not only is an excellent and a reliable tracer for blood cells but also enables the investigators to study the in vivo cell kinetics and map the localization of labelled cells by external gamma scintigraphy. The tracer has the modest half life of 67 hours and decays with the emission of two gamma photons (173 and 247 keV) in high abundance. This technique has provided a powerful tool to study the in vivo cell kinetics in health and localize abnormal lesions in diseases which invoke intense focal cellular concentration

Radiolabelled blood elements techniques and clinical applications

Energy Technology Data Exchange (ETDEWEB)

Thakur, M L

1993-12-31

Over the past few years, in nuclear medicine, the diagnostic applications of radiolabelled blood elements in general, and of radiolabelled white blood cells in particular, have become increasingly popular. This is primarily due to the introduction of lipid soluble {sup 111}In-oxine as an agent, which not only is an excellent and a reliable tracer for blood cells but also enables the investigators to study the in vivo cell kinetics and map the localization of labelled cells by external gamma scintigraphy. The tracer has the modest half life of 67 hours and decays with the emission of two gamma photons (173 and 247 keV) in high abundance. This technique has provided a powerful tool to study the in vivo cell kinetics in health and localize abnormal lesions in diseases which invoke intense focal cellular concentration 5 figs, 2 tabs

Chemical composition of free tropospheric aerosol for PM1 and coarse mode at the high alpine site Jungfraujoch

Directory of Open Access Journals (Sweden)

J. Cozic

2008-01-01

Full Text Available The chemical composition of submicron (fine mode and supermicron (coarse mode aerosol particles has been investigated at the Jungfraujoch high alpine research station (3580 m a.s.l., Switzerland as part of the GAW aerosol monitoring program since 1999. A clear seasonality was observed for all major components throughout the period with low concentrations in winter (predominantly free tropospheric aerosol and higher concentrations in summer (enhanced vertical transport of boundary layer pollutants. In addition, mass closure was attempted during intensive campaigns in March 2004, February–March 2005 and August 2005. Ionic, carbonaceous and non-refractory components of the aerosol were quantified as well as the PM1 and coarse mode total aerosol mass concentrations. A relatively low conversion factor of 1.8 for organic carbon (OC to particulate organic matter (OM was found in winter (February–March 2005. Organics, sulfate, ammonium, and nitrate were the major components of the fine aerosol fraction that were identified, while calcium and nitrate were the only two measured components contributing to the coarse mode. The aerosol mass concentrations for fine and coarse mode aerosol measured during the intensive campaigns were not typical of the long-term seasonality due largely to dynamical differences. Average fine and coarse mode concentrations during the intensive field campaigns were 1.7 μg m⁻³ and 2.4 μg m⁻³ in winter and 2.5 μg m⁻³ and 2.0 μg m⁻³ in summer, respectively. The mass balance of aerosols showed higher contributions of calcium and nitrate in the coarse mode during Saharan dust events (SDE than without SDE.

The effect of arsenic thermal diffusion on the morphology and photoluminescence properties of sub-micron ZnO rods

Energy Technology Data Exchange (ETDEWEB)

Ding Meng [Department of Physics, Jilin University, Changchun 130023 (China); Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130021 (China); Yao Bin, E-mail: binyao@jlu.edu.c [Department of Physics, Jilin University, Changchun 130023 (China); Zhao Dongxu, E-mail: dxzhao2000@yahoo.com.c [Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130021 (China); Fang Fang; Shen Dezhen; Zhang Zhenzhong [Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130021 (China)

2010-05-31

As-doped sub-micron ZnO rods were realized by a simple thermal diffusion process using a GaAs wafer as an arsenic resource. The surface of the sub-micron ZnO rods became rough and the morphology of As-doped sub-micron ZnO rods changed markedly with increasing diffusion temperature. From the results of energy-dispersive X-ray spectroscopy, X-ray diffraction and photoluminescence, arsenic elements were confirmed to be introduced into the sub-micron ZnO rods. The acceptor ionization energy was deduced to be about 110 meV based on the temperature-dependent PL spectra.

The effect of arsenic thermal diffusion on the morphology and photoluminescence properties of sub-micron ZnO rods

International Nuclear Information System (INIS)

Ding Meng; Yao Bin; Zhao Dongxu; Fang Fang; Shen Dezhen; Zhang Zhenzhong

2010-01-01

As-doped sub-micron ZnO rods were realized by a simple thermal diffusion process using a GaAs wafer as an arsenic resource. The surface of the sub-micron ZnO rods became rough and the morphology of As-doped sub-micron ZnO rods changed markedly with increasing diffusion temperature. From the results of energy-dispersive X-ray spectroscopy, X-ray diffraction and photoluminescence, arsenic elements were confirmed to be introduced into the sub-micron ZnO rods. The acceptor ionization energy was deduced to be about 110 meV based on the temperature-dependent PL spectra.

Light emitting diode with high aspect ratio submicron roughness for light extraction and methods of forming

Science.gov (United States)

Li, Ting [Ventura, CA

2011-04-26

The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. High aspect ratio, submicron roughness is formed on the light emitting surface by transferring a thin film metal hard-mask having submicron patterns to the surface prior to applying a reactive ion etch process. The submicron patterns in the metal hard-mask can be formed using a low cost, commercially available nano-patterned template which is transferred to the surface with the mask. After subsequently binding the mask to the surface, the template is removed and the RIE process is applied for time duration sufficient to change the morphology of the surface. The modified surface contains non-symmetric, submicron structures having high aspect ratio which increase the efficiency of the device.

Aerosol chemical composition at Cabauw, The Netherlands as observed in two intensive periods in May 2008 and March 2009

Directory of Open Access Journals (Sweden)

A. A. Mensah

2012-05-01

Full Text Available Observations of aerosol chemical composition in Cabauw, the Netherlands, are presented for two intensive measurement periods in May 2008 and March 2009. Sub-micron aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS and is compared to observations from aerosol size distribution measurements as well as composition measurements with a Monitor for AeRosol and GAses (MARGA based instrument and a Thermal-Desorption Proton-Transfer-Reaction Mass-Spectrometer (TD-PTR-MS. An overview of the data is presented and the data quality is discussed. In May 2008 enhanced pollution was observed with organics contributing 40% to the PM₁ mass. In contrast the observed average mass loading was lower in March 2009 and a dominance of ammonium nitrate (42% was observed. The semi-volatile nature of ammonium nitrate is evident in the diurnal cycles with maximum concentrations observed in the morning hours in May 2008 and little diurnal variation observed in March 2009. Size dependent composition data from AMS measurements are presented and show a dominance of organics in the size range below 200 nm. A higher O:C ratio of the organics is observed for May 2008 than for March 2009. Together with the time series of individual tracer ions this shows the dominance of OOA over HOA in May 2008.

Fabrication of sub-micron whole waffer SIS tunnel junctions for millimeter wave mixers

International Nuclear Information System (INIS)

Huq, S.E.; Blamire, M.G.; Evetts, J.E.; Hasko, D.G.; Ahmed, H.

1991-01-01

As a part of a programme for the development of a space-qualified sub-mm-wave mixer operating in the region of one terahertz we have been developing the processes required for the fabrication of submicron whole wafer tunnel junctions. Using the self-aligned whole-wafer process (SAWW) with electron beam lithography we have been able to reliably fabricate high quality (V m > 20 mV) submicron tunnel junctions from whole wafer Nb/AlO x /Nb structures. In particular we show that the junction quality is independent of size down to 0.3 μm 2 junction area. The problems of film stress, anodization, registration for electron beam lithography and lift-off, which limit the yield of good quality sub-micron scale junctions are addressed in this paper

Characteristics of aerosol particles and trace gases in ship exhaust plumes

Science.gov (United States)

Drewnick, F.; Diesch, J.; Borrmann, S.

2011-12-01

Gaseous and particulate matter from marine vessels gain increasing attention due to their significant contribution to the anthropogenic burden of the atmosphere, implying the change of the atmospheric composition and the impact on local and regional air quality and climate (Eyring et al., 2010). As ship emissions significantly affect air quality of onshore regions, this study deals with various aspects of gas and particulate plumes from marine traffic measured near the Elbe river mouth in northern Germany. In addition to a detailed investigation of the chemical and physical particle properties from different types of commercial marine vessels, we will focus on the chemistry of ship plumes and their changes while undergoing atmospheric processing. Measurements of the ambient aerosol, various trace gases and meteorological parameters using a mobile laboratory (MoLa) were performed on the banks of the Lower Elbe which is passed on average, daily by 30 ocean-going vessels reaching the port of Hamburg, the second largest freight port of Europe. During 5 days of sampling from April 25-30, 2011 170 commercial marine vessels were probed at a distance of about 1.5-2 km with high temporal resolution. Mass concentrations in PM1, PM2.5 and PM10 and number as well as PAH and black carbon (BC) concentrations in PM1 were measured; size distribution instruments covered the size range from 6 nm up to 32 μm. The chemical composition of the non-refractory aerosol in the submicron range was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase species analyzers monitored various trace gas concentrations in the air and a weather station provided meteorological parameters. Additionally, a wide spectrum of ship information for each vessel including speed, size, vessel type, fuel type, gross tonnage and engine power was recorded via Automatic Identification System (AIS) broadcasts. Although commercial marine vessels powered by diesel engines consume high

Increases to Biogenic Secondary Organic Aerosols from SO2 and NOx in the Southeastern US

Science.gov (United States)

Russell, L. M.; Liu, J.; Ruggeri, G.; Takahama, S.; Claflin, M. S.; Ziemann, P. J.; Lee, A.; Murphy, B.; Pye, H. O. T.; Ng, N. L.; McKinney, K. A.; Surratt, J. D.

2017-12-01

During the 2013 Southern Oxidant and Aerosol Study, Fourier Transform Infrared Spectroscopy (FTIR) and Aerosol Mass Spectrometer (AMS) measurements of submicron mass were collected at Look Rock, Tennessee, and Centreville, Alabama. The low NOx, low wind, little rain, and increased daytime isoprene emissions led to multi-day stagnation events at Look Rock that provided clear evidence of particle-phase sulfate enhancing biogenic secondary organic aerosol (bSOA) by selective uptake. Organic mass (OM) sources were apportioned as 42% "vehicle-related" and 54% bSOA, with the latter including "sulfate-related bSOA" that correlated to sulfate (r=0.72) and "nitrate-related bSOA" that correlated to nitrate (r=0.65). Single-particle mass spectra showed three composition types that corresponded to the mass-based factors with spectra cosine similarity of 0.93 and time series correlations of r>0.4. The vehicle-related OM with m/z 44 was correlated to black carbon, "sulfate-related bSOA" was on particles with high sulfate, and "nitrate-related bSOA" was on all particles. The similarity of the m/z spectra (cosine similarity=0.97) and the time series correlation (r=0.80) of the "sulfate-related bSOA" to the sulfate-containing single-particle type provide evidence for particle composition contributing to selective uptake of isoprene oxidation products onto particles that contain sulfate from power plants. Since Look Rock had much less NOx than Centreville, comparing the bSOA at the two sites provides an evaluation of the role of NOx for bSOA. CO and submicron sulfate and OM concentrations were 15-60 % higher at Centreville than at Look Rock but their time series had moderate correlations of r= 0.51, 0.54, and 0.47, respectively. However, NOx had no correlation (r=0.08) between the two sites. OM correlated with the higher NOx levels at Centreville but with O3 at Look Rock. OM sources identified by Positive Matrix Factorization had three very similar factors at both sites from FTIR

Novel Translucent and Strong Submicron Alumina Ceramics for Dental Restorations.

Science.gov (United States)

Zhao, M; Sun, Y; Zhang, J; Zhang, Y

2018-03-01

An ideal ceramic restorative material should possess excellent aesthetic and mechanical properties. We hypothesize that the high translucency and strength of polycrystalline ceramics can be achieved through microstructural tailoring. The aim of this study is to demonstrate the superior optical and mechanical properties of a new class of submicron grain-sized alumina ceramics relative to the current state-of-the-art dental ceramic materials. The translucency, the in-line transmission ( T IT ) in particular, of these submicron alumina ceramics has been examined with the Rayleigh-Gans-Debye light-scattering model. The theoretical predictions related very well with the measured T IT values. The translucency parameter ( TP) and contrast ratio ( CR) of the newly developed aluminas were measured with a reflectance spectrophotometer on a black-and-white background. For comparison, the T IT , TP, and CR values for a variety of dental ceramics, mostly measured in-house but also cited from the literature, were included. The flexural strength of the aluminas was determined with the 4-point bending test. Our findings have shown that for polycrystalline alumina ceramics, an average grain size ceramic and zirconias, including the most translucent cubic-containing zirconias. The strength of these submicron grain-sized aluminas was significantly higher than that of the cubic-containing zirconia (e.g., Zpex Smile) and lithia-based glass-ceramics (e.g., IPS e.max CAD HT). A coarse-grained alumina could also reach a translucency level comparable to that of dental porcelain. However, the relatively low strength of this material has limited its clinical indications to structurally less demanding applications, such as orthodontic brackets. With a combined high strength and translucency, the newly developed submicron grain-sized alumina may be considered a suitable material for dental restorations.

Laser plasmas as x-ray sources for lithographic imaging of submicron structures

International Nuclear Information System (INIS)

Bijkerk, F.; van Dorssen, G.E.; van der Wiel, M.J.

1988-01-01

Laser radiation can be used efficiently to generate x-rays for lithographic imaging of submicron patterns, e.g., for VLSI device fabrication. Due to their short wavelength and high average power, excimer lasers show much potential for this application. Results are presented of scaling studies for high repetition rate excimer laser application, using the frequency doubled output of a low repetition rate Nd:YAG/Glass laser. Spectral and spatial characteristics of x-ray emission of the laser plasma are shown. The power density in the laser focus was 3 x 10 12 W/cm 2 . With this source Si x-ray masks with submicron Au absorber profiles are imaged into high sensitivity x-ray photoresist. For the exposures 80 laser shots sufficed to yield high quality submicron structures. Extrapolation of the results to a high power excimer laser reduces the exposure time of the photoresists to several seconds, enabling a wafer throughput at an industrial level

A new route for the synthesis of submicron-sized LaB6

International Nuclear Information System (INIS)

Lihong, Bao; Wurentuya,; Wei, Wei; Tegus, O.

2014-01-01

Submicron crystalline LaB 6 has been successfully synthesized by a solid-state reaction of La 2 O 3 with NaBH 4 at 1200 °C. The effects of reaction temperature on the crystal structure, grain size and morphology were investigated by X-ray diffraction, scanning electron microscope and transmission electron microscope. It is found that when the reaction temperature is in the range of 1000–1100 °C, there are ultrafine nanoparticles and nanocrystals that coexist. When the reaction temperature elevated to 1200 °C, the grain morphology transformed from ultrafine nanoparticle to submicron crystals completely. High resolution transmission electron microscope images fully confirm the formation of LaB 6 cubic structure. - Highlights: • Single-phased LaB 6 have been synthesized by a solid-state reaction in a continuous evacuating process. • The reaction temperature has a important effect on the phase composition. • The grain size increase from nano-size to submicron with increasing reaction temperature

Manufacturing a submicron structure using a liquid precursor

NARCIS (Netherlands)

Ishihara, R.; Van de Zwan, M.; Trifunovic, M.

2014-01-01

Methods for manufacture of a submicron semiconductor structure on a substrate are described. The method may comprise: forming at least one template layer over a support substrate; forming one or more template structures, preferably one or more recesses and/or mesas, in said template layer, said one

Radiolabeling Of Albumin Particles With Yttrium-90

International Nuclear Information System (INIS)

Nguyen Thi Thu; Nguyen Thi Khanh Giang; Bui Van Cuong, Vo Thi Cam Hoa

2011-01-01

This paper presents the process of the radiolabeling of microaggregated albumin particles with radionuclide Yttrium-90 using the directed method. The albumin microsphere kit was prepared in sodium phosphate buffer. The original solution includes 2 mg albumin particle and 0.5 mg stannous chloride dihydrate. The albumin particles size was ranged from 5 ?m to 30 ?m. The mixture was washed three times with phosphate buffer saline, pH 7.2 by centrifugation and suspended in 0.5 M sodium acetate buffer, pH 6. Yttrium - 90 in 1.0 M acetic acid was collected from 90 Sr/ 90 Y generator. The labeling of the particles with Y-90 (185 MBq) was performed at pH 5.5 in acetate buffer with agitating for 60 min at room temperature. The labeled albumin suspensions were centrifuged at 3000 rpm for 15 min. Labeling yields was calculated using centrifugation, filtration and compared with paper chromatography, which is developed in the Tris Acetic EDTA. In this system, the unbound of Y-90 migrates to an R f of 0.9-1.0 and the radiolabeled albumin particles remains at the point of origin (R f = 0). The size of 90 Y-albumin particles was compared with the albumin particles in the original solution to be sure that they did not change during the labeling treatment. The radiolabeling yields were more than 80%. The labeled compound was dialysis in phosphate buffer. The radiochemical purity was 98%. The 90 Y- albumin is an ideal radiopharmaceutical for potential use in malignant cancer treatment as brachytherapy. (author)

Radiolabelled peptides: New radiopharmaceuticals for targeted therapy

International Nuclear Information System (INIS)

Chinol, M.

2001-01-01

Radiolabelled peptides have been the focus of an increasing interest by the nuclear medicine community within the last few years. This has mainly been due to successful development of one of these peptides, somatostatin, as a tool to visualise various pathologic conditions known to express a high number of somatostatin receptors. Somatostatin receptors have been identified in different tumours such as neuroendocrine tumours, tumours of the central nervous system, breast, lung and lymphatic tissue. These observations served as the biomolecular basis for the clinical use of radiolabelled somatostatin analogs, which are at present of great interest for diagnostic and therapeutic applications. A promising somatostatin analogue, DOTA-D-Phe 1 -Ty 3 -octreotide, named DOTATOC, has shown favourable biodistribution and high affinity binding to SSTR2 and SSTR5, high hydrophilicity and ease of labelling and stability with 111 In and 90 Y. A clinical trial aimed at evaluating the biodistribution and dosimetry of DOTATOC radiolabelled with 111 In, in anticipation of therapy trials with 90 Y-DOTATOC in patients was undertaken. 111 In-DOTATOC showed favourable pharmacokinetics (fast blood clearance and urinary excretion) and biodistribution, and high affinity to tumours expressing somatostatin receptors (thus, a high residence time in tumour). These results are promising for therapy trials with 90 Y-DOTAOC, for which radiation dosimetry appears acceptable for normal organs (including the red marrow). Moreover, labelling conditions of DOTATOC with 90 Y has been optimised in order to achieve labelling yields of more than 98% and specific activities of greater than 60 GBq (1.6 Ci)/μmol. (author)

Synthesis of sup 14 C-radiolabelled Tilmicosin

Energy Technology Data Exchange (ETDEWEB)

Crouse, G D; Terando, N H [Lilly (Eli) and Co., Indianapolis, IN (USA). Lilly Research Labs.

1989-04-01

Tilmicosin was radiolabelled with carbon-14 on the 3,5-dimethylpiperidinyl sidechain as a requirement for animal metabolism studies. A new radiosynthesis of 3,5-dimethyl-piperidine was developed for this purpose. Incorporation into the desmycosin nucleus was accomplished by a reductive amination reaction. (author).

Synthesis, radiolabeling and biodistribution of a new opioid glucuronide derivative. Ethyl-morphine glucuronide (em-glu)

International Nuclear Information System (INIS)

Enginar, H.

2012-01-01

In current study, ethyl-morphine (em) was synthesized from the morphine and glucuronidated via enzymatic mechanism. The conjugated glucuronide ethyl-morphine (em-glu) was radiolabeled with 131 I using iodogen method. The quality control studies of radiolabeled compound ( 131 I-em-glu) were done with Thin Layer Radio Chromatography to confirm the radiolabeling efficiency. Biodistribution studies of 131 I labeled em-glu were run on healthy male Albino Wistar rats. The distribution figures demonstrated that 131 I-em-glu was eliminated through the small intestine, large intestine and accumulated in urinary bladder both receptor blocked and unblocked biodistribution studies. A greater uptake of the radiolabeled substance was observed in the m.pons, hypothalamus and mid brain than in the other branches of the rats' brains. (author)

Impact of Nano Particles on Cultural Properties in the Atmosphere of Gyeongju National Park Area Using a Proton Beam

Energy Technology Data Exchange (ETDEWEB)

Kim, K. W.; Do, J. Y.; Park, S. Y.; Kim, T. K.; Ha, J. K. [Gyeongju University, Gyeongju (Korea, Republic of)

2008-04-15

The objective of this research is to investigate the physical and chemical characteristics of atmospheric nanoparticles observed at the National Park area of Gyeongju. The elemental compositions of the submicron aerosols were analyzed using a PIXE (proton induced X-ray emission) method with a 3 MV Tandetron accelerator. In addition, submicron aerosols were prepared for a determination of ions using ion chromatography. Aerosol monitoring was conducted for airborne particles less than 1.0 and 2.5 micron. They were collected on nuclepore filters using PM1.0 and PM2.5 cyclone samplers. The impact of air-mass pathway on the characteristics of particulate matter was analyzed at an end point of Gyeongju with backward trajectory results obtained from the HYSPLIT model. The ratio of submicron aerosol to fine particles in the mass concentration was 40 - 50% in the urban area of Seoul and the national park area of Gyeongju. During the monitoring period, Asian Dust storm events occurred at each monitoring site. The contributions of elements to the submicron aerosols were 8% lower in the urban area than in the national park area. However, the contributions of aged ions to submicron aerosols were relatively higher by 42% in the urban area of Seoul. The elementals of the submicron aerosols were categorized as soil-related, anthropogenic-related, and aerosol-acidity-related species based on an enrichment factor analysis. The average mass fraction of soil-related elements was approximately 20% for Seoul and 75% for Gyeongju. That of the aerosol-acidity-related specie was higher in Seoul and showed a big difference among Asian Dust storm events, non-Asian Dust storm events, and clear atmospheric conditions due to precipitation. Anthropogenic-related elements accounted for 11.7% in Seoul and 5.7% in Gyeongju. S, SO42- and the anthropogenic related elements like Cr, Cd, Pb, which can not be derived from stone materials themselves, were detected both on the stone surface and in

Impact of Nano Particles on Cultural Properties in the Atmosphere of Gyeongju National Park Area Using a Proton Beam

International Nuclear Information System (INIS)

Kim, K. W.; Do, J. Y.; Park, S. Y.; Kim, T. K.; Ha, J. K.

2008-04-01

The objective of this research is to investigate the physical and chemical characteristics of atmospheric nanoparticles observed at the National Park area of Gyeongju. The elemental compositions of the submicron aerosols were analyzed using a PIXE (proton induced X-ray emission) method with a 3 MV Tandetron accelerator. In addition, submicron aerosols were prepared for a determination of ions using ion chromatography. Aerosol monitoring was conducted for airborne particles less than 1.0 and 2.5 micron. They were collected on nuclepore filters using PM1.0 and PM2.5 cyclone samplers. The impact of air-mass pathway on the characteristics of particulate matter was analyzed at an end point of Gyeongju with backward trajectory results obtained from the HYSPLIT model. The ratio of submicron aerosol to fine particles in the mass concentration was 40 - 50% in the urban area of Seoul and the national park area of Gyeongju. During the monitoring period, Asian Dust storm events occurred at each monitoring site. The contributions of elements to the submicron aerosols were 8% lower in the urban area than in the national park area. However, the contributions of aged ions to submicron aerosols were relatively higher by 42% in the urban area of Seoul. The elementals of the submicron aerosols were categorized as soil-related, anthropogenic-related, and aerosol-acidity-related species based on an enrichment factor analysis. The average mass fraction of soil-related elements was approximately 20% for Seoul and 75% for Gyeongju. That of the aerosol-acidity-related specie was higher in Seoul and showed a big difference among Asian Dust storm events, non-Asian Dust storm events, and clear atmospheric conditions due to precipitation. Anthropogenic-related elements accounted for 11.7% in Seoul and 5.7% in Gyeongju. S, SO42- and the anthropogenic related elements like Cr, Cd, Pb, which can not be derived from stone materials themselves, were detected both on the stone surface and in

Investigation of molten corium-concrete interaction phenomena and aerosol release

International Nuclear Information System (INIS)

Spencer, B.W.; Thompson, D.H.; Armstrong, D.R.; Fink, J.K.; Gunther, W.H.; Kilsdonk, D.J.; Sehgal, B.R.

1987-01-01

The Electric Power Research Institute is sponsoring a program of laboratory investigations at Argonne National Laboratory to study the interaction between molten core materials and reactor concrete basemats during postulated severe reactor accidents, with particular emphasis on measurements of the magnitude and chemical species present in the aerosol releases. The approach in this program is to sustain internal heat generation in reactor-material corium using direct electrical heating and to develop test operating and diagnostics capabilities with a series of small- and intermediate-scale scoping tests followed by fully instrumented large-scale testing. Real reactor materials (UO 2 , ZrO 2 , oxides of stainless steel, plus metallics) are used, with small amounts of La 2 O 3 , BaO, and SrO added to simulate nonvolatile fission products. In intermediate-scale scoping tests completed to date, corium inventories of up to 29 kg have been heated with power inputs in excess of 1 kW/kg melt. The measured concrete ablation rates have ranged from 0.9 to 3.9 mm/minute. Aerosol samples have been examined using a scanning electron microscope and show submicron particles, 2-6 micrometer spheres, and agglomerates that range from a few micrometers to string 13 micrometers in length

Radiolabeled platelets

International Nuclear Information System (INIS)

Datz, F.L.; Taylor, A.T.

1986-01-01

Initial interest in developing techniques to radiolabel platelets was spurred by the lack of an accurate method for measuring platelet life span in both normals and in thrombocytopenic patients. Early investigators could obtain only rough estimates of platelet life spans by monitoring the platelet counts of thrombocytopenic patients undergoing platelet transfusions. Labels were also sought that would allow imaging of platelets in vivo in order to better understand the pathophysiology of atherosclerosis, thrombophlebitis, and clotting disorders, and to improve the clinical diagnosis of these diseases. Two types of platelet labels were investigated: cohort (pulse) labels and random labels. Cohort labels are taken up by megakaryocytes in the bone marrow and incorporated in the DNA and other components of the forming platelet. In theory, only freshly released platelets of a uniform age are labeled. Random labels, on the other hand, tag platelets in the peripheral blood, labeling platelets of all ages

Comparison of endogenous and radiolabeled bile acid excretion in patients with idiopathic chronic diarrhea

International Nuclear Information System (INIS)

Schiller, L.R.; Bilhartz, L.E.; Santa Ana, C.A.

1990-01-01

Fecal recovery of radioactivity after ingestion of a bolus of radiolabeled bile acid is abnormally high in most patients with idiopathic chronic diarrhea. To evaluate the significance of this malabsorption, concurrent fecal excretion of both exogenous radiolabeled bile acid and endogenous (unlabeled) bile acid were measured in patients with idiopathic chronic diarrhea. Subjects received a 2.5-microCi oral dose of taurocholic acid labeled with 14C in the 24th position of the steroid moiety. Endogenous bile acid excretion was measured by a hydroxysteroid dehydrogenase assay on a concurrent 72-h stool collection. Both radiolabeled and endogenous bile acid excretion were abnormally high in most patients with chronic diarrhea compared with normal subjects, even when equivoluminous diarrhea was induced in normal subjects by ingestion of osmotically active solutions. The correlation between radiolabeled and endogenous bile acid excretion was good. However, neither radiolabeled nor endogenous bile acid excretion was as abnormal as is typically seen in patients with ileal resection, and none of these diarrhea patients responded to treatment with cholestyramine with stool weights less than 200 g. These results suggest (a) that this radiolabeled bile acid excretion test accurately reflects excess endogenous bile acid excretion; (b) that excess endogenous bile acid excretion is not caused by diarrhea per se; (c) that spontaneously occurring idiopathic chronic diarrhea is often associated with increased endogenous bile acid excretion; and (d) that bile acid malabsorption is not likely to be the primary cause of diarrhea in most of these patients

Experimental determination of the dynamic shape factor of primary sodium peroxide aerosols

International Nuclear Information System (INIS)

Barbe, M.

1985-09-01

A hypothetical accident in a fast breeeder reactor could cause aerosols to be generated in a sodium fire. The computer codes relative to the modeling of such accidents make it necessary to use various input parameters among which the dynamic shape factor kappa of the aerosols produced. This study concerns the shape factor of sodium peroxide; the discrepancies between the values of this parameter given in the literature justifies the usefulness of our work. We have tried to use the simplest method. The dynamic shape factor is proportional to the ratio of the equivalent volume diameter to the aerodynamic diameter for a given particle. Therefore, these two quantities must be determined. The particles are classified by means of a centrifuge as a function of their aerodynamic diameter; the equivalent volume diameter of the particles thus selected can then be determined by assessing the mass (neutron activation) and the number (electron microscope) on the same sample of particles. Our results show that the dynamic shape factor of sodium peroxide submicronic particles generated by a fire is nearly 1 and the values of this parameter increase with the particles size [fr

Chemical composition of aerosol measurements in the air pollution plume during KORUS-AQ

Science.gov (United States)

Park, T.; Lee, J. B.; Lim, Y. J.; Ahn, J.; Park, J. S.; Soo, C. J.; Kim, J.; Park, S.; Lee, Y.; Desyaterik, Y.; Collett, J. L., Jr.; Lee, T.

2017-12-01

The Korean peninsula is a great place to study different sources of the aerosols: urban, rural and marine. In addition, Seoul is one of the large metropolitan areas in the world and has a variety of sources because half of the Korean population lives in Seoul, which comprises only 12% of the country's area. To understand the chemical composition of aerosol form long-range transport and local sources better, an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed on an airborne platform (NASA DC-8 aircraft). The HR-ToF-AMS is capable of measuring non-refractory size resolved chemical composition of submicron particle(NR-PM1) in the air pollution plume, including mass concentration of organic carbon, nitrate, sulfate, and ammonium with 10 seconds time resolution. The measurements were performed twenty times research flight for understanding characteristic of the air pollution from May to June, 2016 on the South Korean peninsula during KORUS-AQ 2016 campaign. The scientific goal of this study is to characterize aerosol chemical properties and mass concentration in order to understand the role of the long-range transport from northeast Asia to South Korea, and influence of the local sources. To brief, organics dominated during all of flights. Also, organics and nitrate were dominant around energy industrial complex near by Taean, South Korea. The presentation will provide an overview of the composition of NR-PM1 measured in air pollution plumes, and deliver detail information about width, depth and spatial distribution of the pollutant in the air pollution plumes. The results of this study will provide high temporal and spatial resolved details on the air pollution plumes, which are valuable input parameters of aerosol properties for the current air quality models.

Mechanisms of Current Transfer in Electrodeposited Layers of Submicron Semiconductor Particles

Science.gov (United States)

Zhukov, N. D.; Mosiyash, D. S.; Sinev, I. V.; Khazanov, A. A.; Smirnov, A. V.; Lapshin, I. V.

2017-12-01

Current-voltage ( I- V) characteristics of conductance in multigrain layers of submicron particles of silicon, gallium arsenide, indium arsenide, and indium antimonide have been studied. Nanoparticles of all semiconductors were obtained by processing initial single crystals in a ball mill and applied after sedimentation onto substrates by means of electrodeposition. Detailed analysis of the I- V curves of electrodeposited layers shows that their behavior is determined by the mechanism of intergranular tunneling emission from near-surface electron states of submicron particles. Parameters of this emission process have been determined. The proposed multigrain semiconductor structures can be used in gas sensors, optical detectors, IR imagers, etc.

Variability of aerosol, gaseous pollutants and meteorological characteristics associated with changes in air mass origin at the SW Atlantic coast of Iberia

Directory of Open Access Journals (Sweden)

J.-M. Diesch

2012-04-01

Full Text Available Measurements of the ambient aerosol were performed at the Southern coast of Spain, within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides project. The field campaign took place from 20 November until 9 December 2008 at the atmospheric research station "El Arenosillo" (37°5'47.76" N, 6°44'6.94" W. As the monitoring station is located at the interface between a natural park, industrial cities (Huelva, Seville and the Atlantic Ocean, a variety of physical and chemical parameters of aerosols and gas phase could be characterized in dependency on the origin of air masses. Backwards trajectories were examined and compared with local meteorology to classify characteristic air mass types for several source regions. Aerosol number and mass as well as polycyclic aromatic hydrocarbons and black carbon concentrations were measured in PM₁ and size distributions were registered covering a size range from 7 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol (NR-PM₁ was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS. Gas phase analyzers monitored various trace gases (O₃, SO₂, NO, NO₂, CO₂ and a weather station provided meteorological parameters.

Lowest average submicron particle mass and number concentrations were found in air masses arriving from the Atlantic Ocean with values around 2 μg m⁻³ and 1000 cm⁻³. These mass concentrations were about two to four times lower than the values recorded in air masses of continental and urban origins. For some species PM₁-fractions in marine air were significantly larger than in air masses originating from Huelva, a closely located city with extensive industrial activities. The largest fraction of sulfate (54% was detected in marine air masses and was to a high degree not neutralized. In addition, small concentrations of

Variability of aerosol, gaseous pollutants and meteorological characteristics associated with changes in air mass origin at the SW Atlantic coast of Iberia

Science.gov (United States)

Diesch, J.-M.; Drewnick, F.; Zorn, S. R.; von der Weiden-Reinmüller, S.-L.; Martinez, M.; Borrmann, S.

2012-04-01

Measurements of the ambient aerosol were performed at the Southern coast of Spain, within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from 20 November until 9 December 2008 at the atmospheric research station "El Arenosillo" (37°5'47.76" N, 6°44'6.94" W). As the monitoring station is located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean, a variety of physical and chemical parameters of aerosols and gas phase could be characterized in dependency on the origin of air masses. Backwards trajectories were examined and compared with local meteorology to classify characteristic air mass types for several source regions. Aerosol number and mass as well as polycyclic aromatic hydrocarbons and black carbon concentrations were measured in PM1 and size distributions were registered covering a size range from 7 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol (NR-PM1) was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase analyzers monitored various trace gases (O3, SO2, NO, NO2, CO2) and a weather station provided meteorological parameters. Lowest average submicron particle mass and number concentrations were found in air masses arriving from the Atlantic Ocean with values around 2 μg m-3 and 1000 cm-3. These mass concentrations were about two to four times lower than the values recorded in air masses of continental and urban origins. For some species PM1-fractions in marine air were significantly larger than in air masses originating from Huelva, a closely located city with extensive industrial activities. The largest fraction of sulfate (54%) was detected in marine air masses and was to a high degree not neutralized. In addition, small concentrations of methanesulfonic acid (MSA), a product of biogenic dimethyl sulfate (DMS) emissions, could be identified in the particle phase

Quantitative autoradiographic mapping of focal herpes simplex virus encephalitis using a radiolabeled antiviral drug

International Nuclear Information System (INIS)

Price, R.

1984-01-01

A method of mapping herpes simplex viral infection comprising administering a radiolabeled antiviral active 5-substituted 1-(2'-deoxy-2'-substituted-D-arabinofuranosyl) pyrimidine nucleoside to the infected subject, and scanning the area in which the infection is to be mapped for the radiolabel

Metabolic comparison of radiolabeled aniline- and phenol-phthaleins with 131I

International Nuclear Information System (INIS)

Avcibasi, Ugur; Avcibasi, Nesibe; Unak, Turan; Unak, Perihan; Mueftueler, Fazilet Zuemruet; Yildirim, Yeliz; Dincalp, Haluk; Guemueser, Fikriye Guel; Dursun, Ebru Rueksen

2008-01-01

The metabolic comparison of aniline- and phenol-phthaleins radiolabeled with 131 I ( 131 I-APH and 131 I-PPH, respectively) has been investigated in this study. To compare the metabolic behavior of these phthaleins and their glucuronide conjugates radiolabeled with 131 I, scintigraphic and biodistributional techniques were applied using male Albino rabbits. The results obtained have shown that these compounds were successfully radioiodinated with a radioiodination yield of about 100%. Maximum uptakes of 131 I-APH and 131 I-PPH, which were metabolized as N- and O-glucuronides, were observed within 2 h in the bladder and in the small intestine, respectively. In the case of verification of considerably up taking of these compounds also by tumors developed in the small intestine and in the bladder tissues, these results can be expected to be encouraging to test these compounds, which will be radiolabeled with other radioiodines such as 125 I, 123 I and 124 I as imaging and therapeutic agents in nuclear medical applications

Metabolic comparison of radiolabeled aniline- and phenol-phthaleins with (131)I.

Science.gov (United States)

Avcibaşi, Uğur; Avcibaşi, Nesibe; Unak, Turan; Unak, Perihan; Müftüler, Fazilet Zümrüt; Yildirim, Yeliz; Dinçalp, Haluk; Gümüşer, Fikriye Gül; Dursun, Ebru Rükşen

2008-05-01

The metabolic comparison of aniline- and phenol-phthaleins radiolabeled with (131)I ((131)I-APH and (131)I-PPH, respectively) has been investigated in this study. To compare the metabolic behavior of these phthaleins and their glucuronide conjugates radiolabeled with (131)I, scintigraphic and biodistributional techniques were applied using male Albino rabbits. The results obtained have shown that these compounds were successfully radioiodinated with a radioiodination yield of about 100%. Maximum uptakes of (131)I-APH and (131)I-PPH, which were metabolized as N- and O-glucuronides, were observed within 2 h in the bladder and in the small intestine, respectively. In the case of verification of considerably up taking of these compounds also by tumors developed in the small intestine and in the bladder tissues, these results can be expected to be encouraging to test these compounds, which will be radiolabeled with other radioiodines such as (125)I, (123)I and (124)I as imaging and therapeutic agents in nuclear medical applications.

Radiolabeling parameters of 177Lu-DOTA-RITUXIMAB

International Nuclear Information System (INIS)

Massicano, Adriana V.F.; Alcarde, Lais F.; Oliveira, Ricardo S.; Mengatti, Jair; Araujo, Elaine B. de

2013-01-01

Cancer treatment using radioimmunotherapy (RIT) has been the focus of much research in the last two decades. In RIT, a radioisotope is coupled to a monoclonal antibody (mAb) to form a tumor-specific target agent to improve the cytocidal effect of the mAbs. RIT allows the systemic delivery of radiation to disease target by mAbs while sparing normal tissues. Rituximab® (Mabthera - Roche) is a chimeric mouse-human monoclonal antibody; it selectively binds with high affinity to the CD20 antigen, a hydrophobic transmembrane protein, which is expressed on B-lymphocytes and in more than 90% of B cell non-Hodgkin's lymphomas (NHL). The conjugation and radiolabeling process involve special conditions of pH and temperature, long processes of manipulation and mixing. All this process can damage the antibody structure and compromise its clinical application. Therefore, these parameters must be largely studied. The aim of this work was to evaluate the best radiolabeling conditions of DOTA-rituximab. Briefly, 10 mg of antibody previously purified by ultrafiltration device was conjugated with DOTA-NHS-ester (Macrocyclics) in 50 fold molar excess. The reaction was conducted for 1 hour in phosphate buffer pH 8.0 and gently mixing at room temperature, remaining for 24 hours under refrigeration. The immunoconjugated was purified by size exclusion column and ultrafiltration device. The radiolabeled parameters studied were: immunoconjugated mass, activity of 177 LuCl 3 , reaction time, temperature and pH. The radiochemical purity of the preparations was determined using analysis by thin layer chromatography (TLC-SG plates). The best studied condition presented radiochemical purity above 95% and the integrity of antibody was preserved. (author)

Elevated Lipoprotein(A Impairs Platelet Radiolabeling Yield

Directory of Open Access Journals (Sweden)

Susanne Granegger

2015-02-01

Full Text Available Objectives: Platelet radiolabeling in clinical routine usually results in labeling efficiencies (LE above 80%. A variety of risk factors and clinical conditions are known to impair platelet labeling yield, among them elevated triglycerides and low-density lipoproteins. The potential influence of lipoprotein(a (Lp(a, an atherogenic lipoprotein particle containing a kringle subunit, which is widely found in the proteins of fibrinolysis pathway, has never been studied. Normal Lp(a levels range below 30 mg/ dl. The exact prevalence of elevated Lp(a is unknown, most likely ranging below 10%. Even more rare is an isolated elevation despite an otherwise normal lipoprotein profile. Methods: We examined the role of isolated elevated Lp(a (> 50 mg/dl, ranging up to 440 mg/dl compared to patients with normal lipid profile. Platelets were radiolabeled with in-111-oxine at 37 °C for 5 minutes using ISORBE-consensus methodology. Results: The findings indicate that already at levels below 100 mg/dl Lp(a decreases LE. LE assessment after cross-incubation of hyper-Lp(a platelets with normal Lp(a plasma and vice versa reveals that platelets rather than the plasmatic environment are responsible for the deterioration of labeling yield. This behavior already has been reported for elevated low-density lipoproteins. Apparently, the quantitative influence of LDL and Lp(a/mg is comparable. Plotting the sum of LDL and Lp(a versus LE reveals a clear significant negative correlation. Conclusion: As extremely elevated Lp(a, particularly above 150 mg/dl, may significantly impair labeling results. We therefore recommend to include extremely elevated Lp(a into the list of parameters, which should be known before performing radiolabeling of human platelets.

Submicron Resolution Spectral-Domain Optical Coherence Tomography

KAUST Repository

Alarousu, Erkki

2013-11-14

Apparatuses and systems for submicron resolution spectral-domain optical coherence tomography (OCT) are disclosed. The system may use white light sources having wavelengths within 400-1000 nanometers, and achieve resolution below 1 .mu.m. The apparatus is aggregated into a unitary piece, and a user can connect the apparatus to a user provided controller and/or light source. The light source may be a supercontinuum source.

Preparation and radiolabeling of human serum albumin (HSA)-coated magnetite nanoparticles for magnetically targeted therapy

International Nuclear Information System (INIS)

Zhang Chunfu; Cao Jinquan; Yin Duanzhi; Wang Yongxian; Feng Yanlin; Tan Jiajue

2004-01-01

In this paper, we describe the preparation of human serum albumin-coated magnetic particles of about 200 nm in diameter with narrow size distribution radiolabeled with 188 Re for the purpose of magnetically targeted therapy. The optimum radiolabeling conditions are: SnCl 2 ·2H 2 O 8 mg/ml, citric acid 20 mg/ml, vitamin C 8 mg/ml, labeling volume 500 μl and a reaction time of 3 h. The stability of the radiolabeled particles is suitable for in vivo study

Method for radiolabeling proteins with technetium-99m

International Nuclear Information System (INIS)

Crockford, D.R.; Rhodes, B.A.

1984-01-01

In accordance with this invention, a substrate to be radiolabeled with technetium-99m is admixed with a buffered stannous chloride composition having a pH between about 4.5 and about 8.5 wherein the stannous chloride is produced from a non-oxidized tin source, the buffered stannous chloride is purged of oxygen and the buffer comprises a mixture of alkali metal biphthalate and an alkali metal tartrate. Alternatively, the buffer may include alkali metal borate or gentisate. The stannous chloride solution is admixed with the buffer and the resultant mixture is neutralized with sodium hydroxide. The neutralized solution then is admixed with the substrate eventually to be radiolabeled with technetium-99m. This solution is allowed to incubate for several hours (usually over 15 hours) in the absence of oxygen and at room temperature

In vitro metabolism of radiolabeled carbohydrates by protective cecal anaerobic bacteria.

Science.gov (United States)

Hume, M E; Beier, R C; Hinton, A; Scanlan, C M; Corrier, D E; Peterson, D V; DeLoach, J R

1993-12-01

Cecal anaerobic bacteria from adult broilers were cultured in media containing .25% glucose or .25% lactose. Media also contained either [14C]-labeled lactose, glucose, galactose, or lactic acid as metabolic tracers. Cultures were analyzed at 4, 8, and 12 h for pH, radiolabeled and unlabeled volatile fatty acids, and lactic acid. The pH values of cultures containing .25% lactose were significantly (P galactose, lactose > glucose. The volatile fatty acids in which radiolabel was most concentrated were acetic acid, propionic acid, or butyric acid.

A Study of Summer and Winter Highly Time-resolved Submicron Aerosol Composition Measured at a Suburban Site in Prague

Czech Academy of Sciences Publication Activity Database

Kubelová, Lucie; Vodička, Petr; Schwarz, Jaroslav; Cusack, Michael; Makeš, Otakar; Ondráček, Jakub; Ždímal, Vladimír

2015-01-01

Roč. 118, OCT 2015 (2015), s. 45-57 ISSN 1352-2310 R&D Projects: GA ČR GAP209/11/1342 Institutional support: RVO:67985858 Keywords : atmospheric aerosol * chemical composition * size distribution Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.459, year: 2015

Sub-micron filter

Science.gov (United States)

Tepper, Frederick [Sanford, FL; Kaledin, Leonid [Port Orange, FL

2009-10-13

Aluminum hydroxide fibers approximately 2 nanometers in diameter and with surface areas ranging from 200 to 650 m.sup.2/g have been found to be highly electropositive. When dispersed in water they are able to attach to and retain electronegative particles. When combined into a composite filter with other fibers or particles they can filter bacteria and nano size particulates such as viruses and colloidal particles at high flux through the filter. Such filters can be used for purification and sterilization of water, biological, medical and pharmaceutical fluids, and as a collector/concentrator for detection and assay of microbes and viruses. The alumina fibers are also capable of filtering sub-micron inorganic and metallic particles to produce ultra pure water. The fibers are suitable as a substrate for growth of cells. Macromolecules such as proteins may be separated from each other based on their electronegative charges.

Submicron particle monitoring of paving and related road construction operations.

Science.gov (United States)

Freund, Alice; Zuckerman, Norman; Baum, Lisa; Milek, Debra

2012-01-01

This study identified activities and sources that contribute to ultrafine and other submicron particle exposure that could trigger respiratory symptoms in highway repair workers. Submicron particle monitoring was conducted for paving, milling, and pothole repair operations in a major metropolitan area where several highway repair workers were identified as symptomatic for respiratory illness following exposures at the 2001 World Trade Center disaster site. Exposure assessments were conducted for eight trades involved in road construction using a TSI P-Trak portable condensation particle counter. Direct readings near the workers' breathing zones and observations of activities and potential sources were logged on 7 days on 27 workers using four different models of pavers and two types of millers. Average worker exposure levels ranged from 2 to 3 times background during paving and from 1 to 4 times background during milling. During asphalt paving, average personal exposures to submicron particulates were 25,000-60,000, 28,000-70,000, and 23,000-37,000 particles/ cm(3) for paver operators, screed operators, and rakers, respectively. Average personal exposures during milling were 19,000-111,000, 28,000-81,000, and 19,000 particles/cm(3) for the large miller operators, miller screed operators, and raker, respectively. Personal peak exposures were measured up to 467,000 and 455,000 particles/cm(3) in paving and milling, respectively. Several sources of submicron particles were identified. These included the diesel and electric fired screed heaters; engine exhaust from diesel powered construction vehicles passing by or idling; raking, dumping, and paving of asphalt; exhaust from the hotbox heater; pavement dust or fumes from milling operations, especially when the large miller started and stopped; and secondhand cigarette smoke. To reduce the potential for health effects in workers, over 40 recommendations were made to control exposures, including improved maintenance of

Variability of aerosol, gaseous pollutants and meteorological characteristics associated with continental, urban and marine air masses at the SW Atlantic coast of Iberia

Science.gov (United States)

Diesch, J.-M.; Drewnick, F.; Zorn, S. R.; von der Weiden-Reinmüller, S.-L.; Martinez, M.; Borrmann, S.

2011-12-01

Measurements of the ambient aerosol were performed at the Southern coast of Spain, within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from 20 November until 9 December 2008 at the atmospheric research station "El Arenosillo" (37°5'47.76" N, 6°44'6.94" W). As the monitoring station is located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean a variety of physical and chemical parameters of aerosols and gas phase could be characterized in dependency on the origin of air masses. Backwards trajectories were examined and compared with local meteorology to classify characteristic air mass types for several source regions. Aerosol number and mass as well as polycyclic aromatic hydrocarbons and black carbon concentrations were measured in PM1 and size distributions were registered covering a size range from 7 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase analyzers monitored various trace gases (O3, SO2, NO, NO2, CO2) and a weather station provided meteorological parameters. Lowest average submicron particle mass and number concentrations were found in air masses arriving from the Atlantic Ocean with values around 2 μg m-3 and 1000 cm-3. These mass concentrations were about two to four times lower than the values recorded in air masses of continental and urban origins. For some species PM1-fractions in marine air were significantly larger than in air masses originating from Huelva, a closely located city with extensive industrial activities. The largest fraction of sulfate (54%) was detected in marine air masses and was to a high degree not neutralized. In addition small concentrations of methanesulfonic acid (MSA), a product of biogenic dimethyl sulfate (DMS) emissions could be identified in the particle phase. In all

Thermophoretic motion behavior of submicron particles in boundary-layer-separation flow around a droplet.

Science.gov (United States)

Wang, Ao; Song, Qiang; Ji, Bingqiang; Yao, Qiang

2015-12-01

As a key mechanism of submicron particle capture in wet deposition and wet scrubbing processes, thermophoresis is influenced by the flow and temperature fields. Three-dimensional direct numerical simulations were conducted to quantify the characteristics of the flow and temperature fields around a droplet at three droplet Reynolds numbers (Re) that correspond to three typical boundary-layer-separation flows (steady axisymmetric, steady plane-symmetric, and unsteady plane-symmetric flows). The thermophoretic motion of submicron particles was simulated in these cases. Numerical results show that the motion of submicron particles around the droplet and the deposition distribution exhibit different characteristics under three typical flow forms. The motion patterns of particles are dependent on their initial positions in the upstream and flow forms. The patterns of particle motion and deposition are diversified as Re increases. The particle motion pattern, initial position of captured particles, and capture efficiency change periodically, especially during periodic vortex shedding. The key effects of flow forms on particle motion are the shape and stability of the wake behind the droplet. The drag force of fluid and the thermophoretic force in the wake contribute jointly to the deposition of submicron particles after the boundary-layer separation around a droplet.

Preparation and radiolabeling of human serum albumin (HSA)-coated magnetite nanoparticles for magnetically targeted therapy

Energy Technology Data Exchange (ETDEWEB)

Zhang Chunfu E-mail: zchunfu@yahoo.com.cn; Cao Jinquan; Yin Duanzhi; Wang Yongxian; Feng Yanlin; Tan Jiajue

2004-12-01

In this paper, we describe the preparation of human serum albumin-coated magnetic particles of about 200 nm in diameter with narrow size distribution radiolabeled with {sup 188}Re for the purpose of magnetically targeted therapy. The optimum radiolabeling conditions are: SnCl{sub 2}{center_dot}2H{sub 2}O 8 mg/ml, citric acid 20 mg/ml, vitamin C 8 mg/ml, labeling volume 500 {mu}l and a reaction time of 3 h. The stability of the radiolabeled particles is suitable for in vivo study.

Ceilometer observations of aerosol layer structure above the Petit Lubéron during ESCOMPTE's IOP 2

Science.gov (United States)

Zéphoris, Marcel; Holin, Hubert; Lavie, Franck; Cenac, Nadine; Cluzeau, Michel; Delas, Olivier; Eideliman, Françoise; Gagneux, Jacqueline; Gander, Alain; Thibord, Corinne

2005-03-01

A modified ceilometer has been used during the second Intensive Observation Period (IOP) of the "Expérience sur Site pour COntraindre les Modèles de Pollution atmosphériques et de Transport d'Émission" (ESCOMPTE) to perform continuous remote observations of aerosol accumulations in the first 3 km of the atmosphere. These observations encompassed an episode of intense particulate and photochemical pollution. The submicronic particles density, measured at an altitude of 600 m, went from a very low point of a few tens of particles per cubic centimeter (at the end of a Mistral episode in the free atmosphere) to a high point of more than 4500 particles per cubic centimeter (when pollutants were trapped by thermal inversions). The main result is that this instrument enables a fine documentation of the mixing layer height and of aerosol particles stratifications and circulation. Airborne aerosol measurements have been made above the mountainous region of Mérindol in order to validate in situ the remote sensing measurements. Ozone measurements near the summit of the mountains as well as in the valley were performed in order to correlate aerosol accumulation and ozone concentration. As a notable example, the two-layer aerosol stratification seen in the first 2 days of IOP 2b in that part of the ESCOMPTE domain confirms the results of another team which used backtrajectories. The low-altitude pollution for this timeframe had a local origin (the Fos industrial area), whereas above 500 m, the air masses had undergone regional-scale transport (from north-eastern Spain). The second major result is the highlighting of a pattern, in sea breeze conditions and in this part of the ESCOMPTE experiment zone, of nocturnal aerosol accumulation at an altitude of between 500 and 2000 m, followed by high ozone concentration the next day.

Aerosol optical properties relevant to regional remote sensing of CCN activity and links to their organic mass fraction: airborne observations over Central Mexico and the US West Coast during MILAGRO/INTEX-B

Science.gov (United States)

Shinozuka, Y.; Clarke, A. D.; Decarlo, P. F.; Jimenez, J. L.; Dunlea, E. J.; Roberts, G. C.; Tomlinson, J. M.; Collins, D. R.; Howell, S. G.; Kapustin, V. N.; McNaughton, C. S.; Zhou, J.

2009-09-01

Remote sensing of cloud condensation nuclei (CCN) would help evaluate the indirect effects of tropospheric aerosols on clouds and climate. To assess its feasibility, we examined relationships of submicron aerosol composition to CCN activity and optical properties observed during the MILAGRO/INTEX-B aircraft campaigns. An indicator of CCN activity, κ, was calculated from hygroscopicity measured under saturation. κ for dry 100 nm particles decreased with increasing organic fraction of non-refractory mass of submicron particles (OMF) as 0.34-0.20×OMF over Central Mexico and 0.47-0.43×OMF over the US West Coast. These fits represent the critical dry diameter, centered near 100 nm for 0.2% supersaturation but varied as κ(-1/3), within measurement uncertainty (~20%). The decreasing trends of CCN activity with the organic content, evident also in our direct CCN counts, were consistent with previous ground and laboratory observations of highly organic particles. The wider range of OMF, 0-0.8, for our research areas means that aerosol composition will be more critical for estimation of CCN concentration than at the fixed sites previously studied. Furthermore, the wavelength dependence of extinction was anti-correlated with OMF as -0.70×OMF+2.0 for Central Mexico's urban and industrial pollution air masses, for unclear reasons. The Angstrom exponent of absorption increased with OMF, more rapidly under higher single scattering albedo, as expected for the interplay between soot and colored weak absorbers (some organic species and dust). Because remote sensing products currently use the wavelength dependence of extinction albeit in the column integral form and may potentially include that of absorption, these regional spectral dependencies are expected to facilitate retrievals of aerosol bulk chemical composition and CCN activity over Central Mexico.

Quantitation of radiolabeled compounds eluting from the HPLC system

International Nuclear Information System (INIS)

Kessler, M.J.

1982-01-01

Three techniques are compared for the quantitation of various radiolabeled compounds eluting in the high performance liquid chromatography system. The first technique requires fraction-collecting the effluent from the HPLC, removing an aliquot to scintillation vials, and counting each fraction in a liquid scintillation counter. The second uses direct interface of the HPLC effluent to a flow-through radioactivity detector. The third involves quantitation of various radiolabeled compounds (proteins, steroids, and nucleotides) by splitting the effluent from the HPLC with an electronic steam splitter, thus diverting a present portion to the fraction collector for further chemical characterization and the remainder to the radioactivity flow detector for direct quantitation. A direct comparison of the chromatograms and the radioactivity counting efficiencies of these three techniques is presented

Sub-Antarctic marine aerosol: dominant contributions from biogenic sources

Directory of Open Access Journals (Sweden)

J. Schmale

2013-09-01

Full Text Available Biogenic influences on the composition and characteristics of aerosol were investigated on Bird Island (54°00' S, 38°03' W in the South Atlantic during November and December 2010. This remote marine environment is characterised by large seabird and seal colonies. The chemical composition of the submicron particles, measured by an aerosol mass spectrometer (AMS, was 21% non-sea-salt sulfate, 2% nitrate, 8% ammonium, 22% organics and 47% sea salt including sea salt sulfate. A new method to isolate the sea spray signature from the high-resolution AMS data was applied. Generally, the aerosol was found to be less acidic than in other marine environments due to the high availability of ammonia, from local fauna emissions. By positive matrix factorisation five different organic aerosol (OA profiles could be isolated: an amino acid/amine factor (AA-OA, 18% of OA mass, a methanesulfonic acid OA factor (MSA-OA, 25%, a marine oxygenated OA factor (M-OOA, 41%, a sea spray OA fraction (SS-OA, 7% and locally produced hydrocarbon-like OA (HOA, 9%. The AA-OA was dominant during the first two weeks of November and found to be related with the hatching of penguins in a nearby colony. This factor, rich in nitrogen (N : C ratio = 0.13, has implications for the biogeochemical cycling of nitrogen in the area as particulate matter is often transported over longer distances than gaseous N-rich compounds. The MSA-OA was mainly transported from more southerly latitudes where phytoplankton bloomed. The bloom was identified as one of three sources for particulate sulfate on Bird Island, next to sea salt sulfate and sulfate transported from South America. M-OOA was the dominant organic factor and found to be similar to marine OA observed at Mace Head, Ireland. An additional OA factor highly correlated with sea spray aerosol was identified (SS-OA. However, based on the available data the type of mixture, internal or external, could not be determined. Potassium was not

A novel method for radiolabeling antigen-binding receptors of lymphocytes

International Nuclear Information System (INIS)

Choi, Y.S.; Lee, M.S.; Rosenspire, A.J.

1983-01-01

Antigen-binding receptor (ABR) molecules have been selectively radiolabeled and isolated from immunized chicken spleen cells. The specific radiolabeling of the receptors has been accomplished by utilizing a novel technique employing lactoperoxidase (LPO) covalently linked to antigen (Ag) for which human gammaglobulin was used. The cell surface ABRs were first bound to the Ag-LPO conjugates through specific recognition sites on the Ag portion of the conjugates. The bound LPO portions were then allowed to catalyze the radioiodination of the ABRs. After radiolabeling, cells were solubilized with detergents, ABRs still bound to Ag-LPO conjugates were directly isolated from the lysates via immunoaffinity chromatography utilizing an immunoaffinity reagent directed toward the antigen portion of the ABR-Ag-LPO complex. The radioactive materials were then analyzed via SDS-PAGE under reducing conditions. Most of the specifically-labeled and isolated materials were immunoglobulin (Ig). Both the membrane-bound form of the heavy chain as well as the secreted form were detected, along with the light chain. An additional polypeptide was also selectively labeled and isolated along with the Ig. This may be a molecule closely associated with the membrane immunoglobulin on the B-cell surface. (author)

Radiolabeling, biodistribution and tumor imaging of stealth liposomes containing methotrexate

International Nuclear Information System (INIS)

Subramanian, N; Arulsudar, N; Chuttani, K; Mishra, P; Sharma, R.K; Murthy, R.S.R

2003-01-01

To study the utility of sterically stabilized liposomes (stealth liposomes) in tumor scintigraphy by studying its biodistribution and accumulation in target tissue after radiolabeling with Technetium-99m (99mTC). Conventional and Stealth liposomes were prepared by lipid film hydration method using methotrexate as model anticancer drug. Radiolabeling of the liposomes was carried out by direct labeling using reduced 99mTc. Experimental conditions for maximum labeling yield were optimized. The stability studies were carried out to check binding strength of the radiolabeled complexes. The blood kinetic study was carried out in rabbits after giving the labeled complex by intravenous administration through ear vein. The biodistribution studies were carried out in the Ehrlich ascites tumor (EAT) bearing mice after intravenous administration through tail vein, showed prolonged circulation in blood and significant increase in the accumulation in tumor for the sterically stabilized liposomes compared to the conventional liposomes. The gamma scintigraphic image shows the distribution of the stealth liposomes in liver, spleen, kidney and tumor. The study gives precise idea about the use of stealth liposomes in tumor scintigraphy and organ distribution studies (Au)

Enhanced specificity in immunoscreening of expression cDNA clones using radiolabeled antigen overlay

International Nuclear Information System (INIS)

Chao, S.; Chao, L.; Chao, J.

1989-01-01

A highly sensitive and specific method has been developed for immunoscreening clones from an expression cDNA library. The procedures utilize a radiolabeled antigen detection method described originally for the immunoblotting of plasma proteins. Screening of rat alpha 1-antitrypsin clones was used. Comparison between Western blots of alpha 1-antitrypsin using both labeled antigen and protein A detection methods showed that the former yielded lower background and greater sensitivity than the latter. Further, this technique was shown to have a lower detection limit of less than 20 ng through Western blot analysis of varying concentrations of alpha 1-antitrypsin. The procedures are based on the expression of the protein by cDNA clones containing the DNA inserts in the correct reading frame. Following the transfer of phage proteins to nitrocellulose membranes, the bivalent antibodies bind monovalently to both nitrocellulose-bound-antigen in the phage lysates and radiolabeled antigen. The radiolabeled antigen overlay method is superior to the protein A detection method in sensitivity, specificity and reproducibility. This improved method can be applied in general for screening expression cDNA libraries, provided that the specific antiserum and radiolabeled antigen are available

Microassay for measurement of binding of radiolabelled ligands to cell surface molecules

International Nuclear Information System (INIS)

Woof, J.M.; Burton, D.R.

1988-01-01

An improved technique for measuring the binding of radiolabelled ligands to cell surface molecules has been developed by modification of a procedure using centrifugation through a water-immiscible oil to separate free and cell-bound ligand. It maximises the percentage of ligand bound since cell-bound and free ligand can be separated easily and reproducibly even when very small reaction volumes are used. This permits low levels of ligand radiolabelling and relatively low numbers of cells to be used

Highly time-resolved urban aerosol characteristics during springtime in Yangtze River Delta, China: insights from soot particle aerosol mass spectrometry

Directory of Open Access Journals (Sweden)

J. Wang

2016-07-01

Full Text Available In this work, the Aerodyne soot particle – aerosol mass spectrometer (SP-AMS was deployed for the first time during the spring of 2015 in urban Nanjing, a megacity in the Yangtze River Delta (YRD of China, for online characterization of the submicron aerosols (PM1. The SP-AMS enables real-time and fast quantification of refractory black carbon (rBC simultaneously with other non-refractory species (ammonium, sulfate, nitrate, chloride, and organics. The average PM1 concentration was found to be 28.2 µg m−3, with organics (45 % as the most abundant component, following by sulfate (19.3 %, nitrate (13.6 %, ammonium (11.1 %, rBC (9.7 %, and chloride (1.3 %. These PM1 species together can reconstruct ∼ 44 % of the light extinction during this campaign based on the IMPROVE method. Chemically resolved mass-based size distributions revealed that small particles especially ultrafine ones (< 100 nm vacuum aerodynamic diameter were dominated by organics and rBC, while large particles had significant contributions from secondary inorganic species. Source apportionment of organic aerosols (OA yielded four OA subcomponents, including hydrocarbon-like OA (HOA, cooking-related OA (COA, semi-volatile oxygenated OA (SV-OOA, and low-volatility oxygenated OA (LV-OOA. Overall, secondary organic aerosol (SOA, equal to the sum of SV-OOA and LV-OOA dominated the total OA mass (55.5 %, but primary organic aerosol (POA, equal to the sum of HOA and COA can outweigh SOA in the early morning and evening due to enhanced human activities. High OA concentrations were often associated with high mass fractions of POA and rBC, indicating the important role of anthropogenic emissions during heavy pollution events. The diurnal cycles of nitrate, chloride, and SV-OOA both showed good anti-correlations with air temperatures, suggesting their variations were likely driven by thermodynamic equilibria and gas-to-particle partitioning. On the other hand

Microreactor and method for preparing a radiolabeled complex or a biomolecule conjugate

Energy Technology Data Exchange (ETDEWEB)

Reichert, David E; Kenis, Paul J. A.; Wheeler, Tobias D; Desai, Amit V; Zeng, Dexing; Onal, Birce C

2015-03-17

A microreactor for preparing a radiolabeled complex or a biomolecule conjugate comprises a microchannel for fluid flow, where the microchannel comprises a mixing portion comprising one or more passive mixing elements, and a reservoir for incubating a mixed fluid. The reservoir is in fluid communication with the microchannel and is disposed downstream of the mixing portion. A method of preparing a radiolabeled complex includes flowing a radiometal solution comprising a metallic radionuclide through a downstream mixing portion of a microchannel, where the downstream mixing portion includes one or more passive mixing elements, and flowing a ligand solution comprising a bifunctional chelator through the downstream mixing portion. The ligand solution and the radiometal solution are passively mixed while in the downstream mixing portion to initiate a chelation reaction between the metallic radionuclide and the bifunctional chelator. The chelation reaction is completed to form a radiolabeled complex.

Investigation of bacterial adherence to a non-precious alloy with radiolabeling method

International Nuclear Information System (INIS)

Sonugelen, M.; Iyiyapici Destan, U.; Oeztuerk, B.; Yurt Lambrecht, F.

2006-01-01

The objective of this study was to investigate the bacterial adherence to a non-precious alloy with radiolabeling method. S. mutans, E. coliand C. albicanswere labeled with 99m Tc by using stannous chloride and their radiolabeling yields were calculated. After the labeling procedure, metal disks (3 mm x 10 mm) were treated with microorganisms. The amount of labeled microorganisms adhered on metal surfaces was determined by activity measurements. The labeling yields for S. mutans, E. coliand C. albicanswere 69.95 ± 7.58%, 78.84 ± 0.44% and 79.71 ± 10.17%, respectively. The mean values for adherence for S. mutans, E. coliand C. albicans on metal samples were 7.02 ± 2.18%, 0.96 ± 0.49% and 8.80 ± 8.24%, respectively. The radiolabeling method could be considered as safe and precise for determining the adherence of microorganisms. (author)

A Detailed Analysis of Aerosols Containing Zn, Pb, and Cl from an Industrial Region of Mexico City

Science.gov (United States)

Moffet, R. C.; Desyaterik, Y.; Hopkins, R. J.; Tivanski, A. V.; Gilles, M. K.; Shutthanandan, V.; Molina, L. T.; Gonzalez-Abraham, R.; Johnson, K. S.; Mugica, V.; Molina, M. J.; Laskin, A.; Prather, K. A.

2008-12-01

Measurements in the Northern Mexico City Metropolitan Area during the March, 2006 MILAGRO campaign revealed the frequent appearance of particles with a characteristically high content of internally mixed Zn, Pb, Cl, and P. A detailed analysis of the chemical and physical properties of these particles was performed using a complementary combination of aerosol measurement techniques. Single particles were analyzed using Aerosol Time-of-Flight Mass Spectrometry (ATOFMS) and Computer Controlled Scanning Electron Microscopy/Energy Dispersive X-Ray spectroscopy (CCSEM/EDX). Proton Induced X-Ray Emission (PIXE) analysis of bulk aerosol samples provided time-resolved mass concentrations of individual elements. The PIXE measurements indicated that Zn is more strongly correlated with Cl than with any other element and that Zn concentrations are higher than other non-ferrous transition metals. The Zn- and Pb - containing particles have both spherical and non-spherical morphologies. Many metal rich particles had needle-like structures and were found to be composed of ZnO and/or Zn(NO3)2-6H2O as indicated by scanning transmission x-ray microscopy/near edge X-ray absorption spectroscopy (STXM/NEXAFS). The Zn and Pb rich particles were primarily in the submicron size range and internally mixed with elemental carbon. The unique chemical associations most closely match signatures acquired for garbage incineration.

Magnetoresistance and magnetization in submicron ferromagnetic gratings

Science.gov (United States)

Shearwood, C.; Blundell, S. J.; Baird, M. J.; Bland, J. A. C.; Gester, M.; Ahmed, H.; Hughes, H. P.

1994-05-01

A technique for engineering micron and submicron scale structures from magnetic films of transition metals has been developed using a combination of electron- and ion-beam lithography enabling high-quality arrays of submicron magnetic Fe wires to be fabricated. This process can be used to fabricate novel devices from a variety of metal combinations which would not be possible by the usual liftoff metallization method. The structure and magnetic properties are reported of an epitaxial 25 nm Fe(001)/GaAs(001) film and the wire gratings which are fabricated from it. The width of the wires in the grating is 0.5 μm for all structures studied, but the separation of each wire is varied in the range 0.5 to 16 μm. An artificially induced shape anisotropy field of around 1 kG, consistent with a magnetostatic calculation, was observed for all separations studied. The field dependence of the magneto-optic Kerr effect and magnetoresistance (MR) data is consistent with a twisted magnetization configuration across the width of the sample beneath saturation for transverse applied fields. In this case, the detailed form of the field dependence of the MR is strikingly modified from that observed in the continuous film and is consistent with coherent rotation of the magnetization.

Highly time-resolved urban aerosol characteristics during springtime in Yangtze River Delta, China: insights from soot particle aerosol mass spectrometry

Science.gov (United States)

Wang, Junfeng; Ge, Xinlei; Chen, Yanfang; Shen, Yafei; Zhang, Qi; Sun, Yele; Xu, Jianzhong; Ge, Shun; Yu, Huan; Chen, Mindong

2016-07-01

In this work, the Aerodyne soot particle - aerosol mass spectrometer (SP-AMS) was deployed for the first time during the spring of 2015 in urban Nanjing, a megacity in the Yangtze River Delta (YRD) of China, for online characterization of the submicron aerosols (PM1). The SP-AMS enables real-time and fast quantification of refractory black carbon (rBC) simultaneously with other non-refractory species (ammonium, sulfate, nitrate, chloride, and organics). The average PM1 concentration was found to be 28.2 µg m-3, with organics (45 %) as the most abundant component, following by sulfate (19.3 %), nitrate (13.6 %), ammonium (11.1 %), rBC (9.7 %), and chloride (1.3 %). These PM1 species together can reconstruct ˜ 44 % of the light extinction during this campaign based on the IMPROVE method. Chemically resolved mass-based size distributions revealed that small particles especially ultrafine ones (cooking-related OA (COA), semi-volatile oxygenated OA (SV-OOA), and low-volatility oxygenated OA (LV-OOA). Overall, secondary organic aerosol (SOA, equal to the sum of SV-OOA and LV-OOA) dominated the total OA mass (55.5 %), but primary organic aerosol (POA, equal to the sum of HOA and COA) can outweigh SOA in the early morning and evening due to enhanced human activities. High OA concentrations were often associated with high mass fractions of POA and rBC, indicating the important role of anthropogenic emissions during heavy pollution events. The diurnal cycles of nitrate, chloride, and SV-OOA both showed good anti-correlations with air temperatures, suggesting their variations were likely driven by thermodynamic equilibria and gas-to-particle partitioning. On the other hand, in contrast to other species, sulfate, and LV-OOA concentrations increased in the afternoon, and showed no positive correlations with relative humidity (RH), likely indicating the contribution from photochemical oxidation is dominant over that of aqueous-phase processing for their formations. The

Bystander responses in three-dimensional cultures containing radiolabelled and unlabelled human cells

International Nuclear Information System (INIS)

Pinto, M.; Azzam, E. I.; Howell, R. W.

2006-01-01

Research on the radiation-induced bystander effect has been carried out mainly in 2-D tissue culture systems. This study uses a 3-D model, wherein apparently normal human diploid fibroblasts (AG1522) are grown in a carbon scaffold, to investigate the induction of a G 1 checkpoint in bystander cells present alongside radiolabelled cells. Cultures were simultaneously pulse-labelled with 3 H-deoxycytidine ( 3 HdC) to selectively irradiate a minor fraction of cells, and bromodeoxyuridine (BrdU) to identify the radiolabelled cells. After thorough washing of cultures, iododeoxyuridine (IdU) was administered to detect proliferating bystander cells. The cultures were harvested at various times thereafter, and cells were reacted with two monoclonal antibodies specific to IdU/BrdU or BrdU, respectively, stained with propidium iodide, and subjected to multi-parameter flow cytometry. Cell-cycle progression was followed in radiolabelled cells (BrdU + ) that were chronically irradiated by low energy beta particles emitted by DNA-incorporated 3 H, and in unlabelled bystander cells (BrdU - ) by a flow cytometry based cumulative labelling index assay. As expected, radiolabelled cells were delayed, in a dose-dependent manner, in G 2 and subsequently G 1 . No delay occurred in progression of bystander cells through G 1 , when the labelled cells were irradiated at dose rates up to 0.32 Gy h -1 . (authors)

Aerosol composition, oxidation properties, and sources in Beijing: results from the 2014 Asia-Pacific Economic Cooperation summit study

Science.gov (United States)

Xu, W. Q.; Sun, Y. L.; Chen, C.; Du, W.; Han, T. T.; Wang, Q. Q.; Fu, P. Q.; Wang, Z. F.; Zhao, X. J.; Zhou, L. B.; Ji, D. S.; Wang, P. C.; Worsnop, D. R.

2015-12-01

The mitigation of air pollution in megacities remains a great challenge because of the complex sources and formation mechanisms of aerosol particles. The 2014 Asia-Pacific Economic Cooperation (APEC) summit in Beijing serves as a unique experiment to study the impacts of emission controls on aerosol composition, size distributions, and oxidation properties. Herein, a high-resolution time-of-flight aerosol mass spectrometer was deployed in urban Beijing for real-time measurements of size-resolved non-refractory submicron aerosol (NR-PM1) species from 14 October to 12 November 2014, along with a range of collocated measurements. The average (±σ) PM1 was 41.6 (±38.9) μg m-3 during APEC, which was decreased by 53 % compared with that before APEC. The aerosol composition showed substantial changes owing to emission controls during APEC. Secondary inorganic aerosol (SIA: sulfate + nitrate + ammonium) showed significant reductions of 62-69 %, whereas organics presented much smaller decreases (35 %). The results from the positive matrix factorization of organic aerosol (OA) indicated that highly oxidized secondary organic aerosol (SOA) showed decreases similar to those of SIA during APEC. However, primary organic aerosol (POA) from cooking, traffic, and biomass-burning sources were comparable to those before APEC, indicating the presence of strong local source emissions. The oxidation properties showed corresponding changes in response to OA composition. The average oxygen-to-carbon level during APEC was 0.36 (±0.10), which is lower than the 0.43 (±0.13) measured before APEC, demonstrating a decrease in the OA oxidation degree. The changes in size distributions of primary and secondary species varied during APEC. SIA and SOA showed significant reductions in large accumulation modes with peak diameters shifting from ~ 650 to 400 nm during APEC, whereas those of POA remained relatively unchanged. The changes in aerosol composition, size distributions, and oxidation

Localisation and mechanism of renal retention of radiolabelled somatostatin analogues

Energy Technology Data Exchange (ETDEWEB)

Melis, Marleen; Krenning, Eric P.; Bernard, Bert F.; Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Barone, Raffaella [UCL, Centre of Nuclear Medicine and Laboratory of PET, Brussels (Belgium); Visser, Theo J. [Erasmus MC, Department of Internal Medicine, Rotterdam (Netherlands)

2005-10-01

Radiolabelled somatostatin analogues, such as octreotide and octreotate, are used for tumour scintigraphy and radionuclide therapy. The kidney is the most important critical organ during such therapy owing to the reabsorption and retention of radiolabelled peptides. The aim of this study was to investigate in a rat model both the localisation and the mechanism of renal uptake after intravenous injection of radiolabelled somatostatin analogues. The multi-ligand megalin/cubilin receptor complex, responsible for reabsorption of many peptides and proteins in the kidney, is an interesting candidate for renal endocytosis of these peptide analogues. For localisation studies, ex vivo autoradiography and micro-autoradiography of rat kidneys were performed 1-24 h after injection of radiolabelled somatostatin analogues and compared with the renal anti-megalin immunohistochemical staining pattern. To confirm a role of megalin in the mechanism of renal retention of [{sup 111}In-DTPA]octreotide, the effects of three inhibitory substances were explored in rats. Renal ex vivo autoradiography showed high cortical radioactivity and lower radioactivity in the outer medulla. The distribution of cortical radioactivity was inhomogeneous. Micro-autoradiography indicated that radioactivity was only retained in the proximal tubules. The anti-megalin immunohistochemical staining pattern showed a strong similarity with the renal [{sup 111}In-DTPA]octreotide ex vivo autoradiograms. Biodistribution studies showed that co-injection of positively charged d-lysine reduced renal uptake to 60% of control. Sodium maleate reduced renal [{sup 111}In-DTPA]octreotide uptake to 15% of control. Finally, cisplatin pre-treatment of rats reduced kidney uptake to 70% of control. Renal retention of [{sup 111}In-DTPA]octreotide is confined to proximal tubules in the rat kidney, in which megalin-mediated endocytosis may play an important part. (orig.)

Albumin-derived peptides efficiently reduce renal uptake of radiolabelled peptides

International Nuclear Information System (INIS)

Vegt, Erik; Eek, Annemarie; Oyen, Wim J.G.; Gotthardt, Martin; Boerman, Otto C.; Jong, Marion de

2010-01-01

In peptide-receptor radionuclide therapy (PRRT), the maximum activity dose that can safely be administered is limited by high renal uptake and retention of radiolabelled peptides. The kidney radiation dose can be reduced by coinfusion of agents that competitively inhibit the reabsorption of radiolabelled peptides, such as positively charged amino acids, Gelofusine, or trypsinised albumin. The aim of this study was to identify more specific and potent inhibitors of the kidney reabsorption of radiolabelled peptides, based on albumin. Albumin was fragmented using cyanogen bromide and six albumin-derived peptides with different numbers of electric charges were selected and synthesised. The effect of albumin fragments (FRALB-C) and selected albumin-derived peptides on the internalisation of 111 In-albumin, 111 In-minigastrin, 111 In-exendin and 111 In-octreotide by megalin-expressing cells was assessed. In rats, the effect of Gelofusine and albumin-derived peptides on the renal uptake and biodistribution of 111 In-minigastrin, 111 In-exendin and 111 In-octreotide was determined. FRALB-C significantly reduced the uptake of all radiolabelled peptides in vitro. The albumin-derived peptides showed different potencies in reducing the uptake of 111 In-albumin, 111 In-exendin and 111 In-minigastrin in vitro. The most efficient albumin-derived peptide (peptide 6), was selected for in vivo testing. In rats, 5 mg of peptide 6 very efficiently inhibited the renal uptake of 111 In-minigastrin, by 88%. Uptake of 111 In-exendin and 111 In-octreotide was reduced by 26 and 33%, respectively. The albumin-derived peptide 6 efficiently inhibited the renal reabsorption of 111 In-minigastrin, 111 In-exendin and 111 In-octreotide and is a promising candidate for kidney protection in PRRT. (orig.)

Field characterization of the PM2.5 Aerosol Chemical Speciation Monitor: insights into the composition, sources, and processes of fine particles in eastern China

Science.gov (United States)

Zhang, Yunjiang; Tang, Lili; Croteau, Philip L.; Favez, Olivier; Sun, Yele; Canagaratna, Manjula R.; Wang, Zhuang; Couvidat, Florian; Albinet, Alexandre; Zhang, Hongliang; Sciare, Jean; Prévôt, André S. H.; Jayne, John T.; Worsnop, Douglas R.

2017-12-01

A PM2.5-capable aerosol chemical speciation monitor (Q-ACSM) was deployed in urban Nanjing, China, for the first time to measure in situ non-refractory fine particle (NR-PM2.5) composition from 20 October to 19 November 2015, along with parallel measurements of submicron aerosol (PM1) species by a standard Q-ACSM. Our results show that the NR-PM2.5 species (organics, sulfate, nitrate, and ammonium) measured by the PM2.5-Q-ACSM are highly correlated (r2 > 0.9) with those measured by a Sunset Lab OC  /  EC analyzer and a Monitor for AeRosols and GAses (MARGA). The comparisons between the two Q-ACSMs illustrated similar temporal variations in all NR species between PM1 and PM2.5, yet substantial mass fractions of aerosol species were observed in the size range of 1-2.5 µm. On average, NR-PM1-2.5 contributed 53 % of the total NR-PM2.5, with sulfate and secondary organic aerosols (SOAs) being the two largest contributors (26 and 27 %, respectively). Positive matrix factorization of organic aerosol showed similar temporal variations in both primary and secondary OAs between PM1 and PM2.5, although the mass spectra were slightly different due to more thermal decomposition on the capture vaporizer of the PM2.5-Q-ACSM. We observed an enhancement of SOA under high relative humidity conditions, which is associated with simultaneous increases in aerosol pH, gas-phase species (NO2, SO2, and NH3) concentrations and aerosol water content driven by secondary inorganic aerosols. These results likely indicate an enhanced reactive uptake of SOA precursors upon aqueous particles. Therefore, reducing anthropogenic NOx, SO2, and NH3 emissions might not only reduce secondary inorganic aerosols but also the SOA burden during haze episodes in China.

Analysis of Marine Aerosol Polysaccharides by Pyrolysis Time-of-Flight Mass Spectrometry

Science.gov (United States)

Lawler, M. J.; Grieman, M. M.; Sengur, I.; Saltzman, E. S.

2017-12-01

The relationship between surface ocean biological productivity and marine cloud formation and properties has been explored for decades, but the impacts of marine biogenic emissions on cloudiness and climate remain highly uncertain. This is in part due to the challenge of directly linking biogenic materials in the surface ocean with cloud-forming aerosol. It has been shown that polysaccharide gel-forming materials, also known as transparent exopolymers, may be mechanically ejected from the sea surface during air bubble bursting (Leck and Bigg, 2005). Existing analysis methods for such aerosols require considerable sample mass and sample preparation. As part of the multi-year seasonal North Atlantic Aerosols and Marine Ecosystems Study (NAAMES), ambient submicron marine aerosol was collected in November 2015 and May 2016 from the R/V Atlantis at using a Particle into Liquid Sampler (PILS). These samples of roughly 15 minute time resolution were frozen and returned to UC Irvine for analysis. A new technique has been developed to attempt to quantify polysaccharide material in these ambient samples. A small subsample (1- 5 µL) is taken from the PILS vial samples and allowed to dry on a Pt ribbon filament in the chemical ionization source region of a time-of-flight mass spectrometer. The sample then undergoes a two-step heating process, in which volatilizable molecules are first desorbed and then non-volatilizable large molecules such as polysaccharides are pyrolyzed. These desorbed molecules and decomposition products are ionized using either O2- or H3O+ reagent ion and are directly sampled into the mass spectrometer. The resulting spectra can then be compared to standards of known polysaccharide materials for quantification and potentially structural and/or compositional information.

Some aspects of the control and management of air pollution by beryllium aerosols

International Nuclear Information System (INIS)

Noor, B.

2000-01-01

The concentration of beryllium aerosols in air of rooms and environment is determined by technological operations which are carried out on ITER and can be rather various. It determines differentiated the approaches to means and methods of the air pollution control. It is expedient to classify concentration Be, arising in air. Criterion of classification can be concentration of an impurity and its exposition. In tests of various duration are determined different on value of concentration Be in air of a working zone. At non-stationary processes of allocation the short-term tests have significant dispersion and allow to reveal both low and high meanings of concentration. This difference in conditions of astable allocation Be in air of a working zone can make the order and more. The long test in many respects smooths possible bursts of concentration, that does not allow to estimate real danger of technological operation or process. The high concentration Be can render decisive toxic astion on a human organism at high levels of pollution. The presence of submicronal particles Be, formed at work ITER presumably should strengthen effect of influence on organism. It is possible to explain it to that alongside with traditional toxic effect of aerosols Be, in addition can impose the mechanism action of a submicronal dust. With the purpose of increase information of tests and opportunity of the forecast of the air pollution levels the mathematical model of logarithmic normal distribution can be used. Submitting data of sampling in logarithmic probable grid, it is possible to carry out the analysis on two parameters: the median and the logarithmic standard. The existing standards and rules of the contents Be with reference to conditions ITER are expedient for differentiating with the account toxicity, exposition, affection on a human organism. The distinctions in allowable concentration Be in air on different sites in rooms allow to create more effective and economic methods

Influence of locational states of submicron fibers added into matrix on mechanical properties of plain-woven Carbon Fiber Composite

Directory of Open Access Journals (Sweden)

Kumamoto Soichiro

2016-01-01

Full Text Available The aim of this study was to show the influence of locational states of submicron fibers added into epoxy matrix on mechanical properties of modified plane-woven carbon fiber reinforced plastic (CFRP. To change the locational states of submicron fibers, two kinds of fabrication processes were applied in preparing specimen by hand lay-up method. Submicron fibers were simply added into epoxy resin with ethanol after they were stirred by a dispersion process using homogenizer to be located far from the interface between reinforcement and matrix. In contrast, submicron fibers were attached onto the carbon fibers by injecting from a spray nozzle accompanying with ethanol to be located near the interface, after they were tentatively contained in ethanol. The plain-woven CFRP plates were fabricated by hand lay-up method and cured at 80 degree-C for 1 hour and then at 150 degree-C for 3 hours. After curing, the plain-woven CFRP plates were cut into the dimension of specimen. Tensile shear strength and Mode-II fracture toughness of CFRP were determined by tensile lap-shear test and End-notched flexure(ENF test, respectively. When submicron fibers were located far from the interface between carbon fibers and epoxy resin, tensile shear strength and Mode-II fracture toughness of CFRP were improved 30% and 18% compared with those of unmodified case. The improvement ratio in modified case was rather low (about few percentages in the case where submicron fibers were located near the interface. The result suggested that crack propagation should be prevented when submicron fibers were existed far from the interface due to the effective stress state around the crack tip.

A spectrometer for submicron particles

International Nuclear Information System (INIS)

Pourprix, M.

1995-01-01

The electrostatic spectrometer for aerosol particles, is composed of two coaxial parallel conductive disks between which an electric field is established; an annular slot in the first disk allows for the atmosphere air intake. Suction and injection systems, and a third intermediate conductive disk are used to carry out a dynamic confinement that allows for the separation of particles having various electronic mobility and the determination of the suspended particle size distribution. Application to aerosol size spectrum determination and air quality monitoring

Degradation of CMOS image sensors in deep-submicron technology due to γ-irradiation

Science.gov (United States)

Rao, Padmakumar R.; Wang, Xinyang; Theuwissen, Albert J. P.

2008-09-01

In this work, radiation induced damage mechanisms in deep submicron technology is resolved using finger gated-diodes (FGDs) as a radiation sensitive tool. It is found that these structures are simple yet efficient structures to resolve radiation induced damage in advanced CMOS processes. The degradation of the CMOS image sensors in deep-submicron technology due to γ-ray irradiation is studied by developing a model for the spectral response of the sensor and also by the dark-signal degradation as a function of STI (shallow-trench isolation) parameters. It is found that threshold shifts in the gate-oxide/silicon interface as well as minority carrier life-time variations in the silicon bulk are minimal. The top-layer material properties and the photodiode Si-SiO2 interface quality are degraded due to γ-ray irradiation. Results further suggest that p-well passivated structures are inevitable for radiation-hard designs. It was found that high electrical fields in submicron technologies pose a threat to high quality imaging in harsh environments.

Highly efficient method for 125I-radiolabeling of biomolecules using inverse-electron-demand Diels-Alder reaction.

Science.gov (United States)

Choi, Mi Hee; Shim, Ha Eun; Yun, Seong-Jae; Kim, Hye Rim; Mushtaq, Sajid; Lee, Chang Heon; Park, Sang Hyun; Choi, Dae Seong; Lee, Dong-Eun; Byun, Eui-Baek; Jang, Beom-Su; Jeon, Jongho

2016-04-19

In this report, we present a rapid and highly efficient method for radioactive iodine labeling of trans-cyclooctene group conjugated biomolecules using inverse-electron-demand Diels-Alder reaction. Radioiodination reaction of the tetrazine structure was carried out using the stannylated precursor 2 to give 125 I-labeled azide ([ 125 I]1) with high radiochemical yield (65±8%) and radiochemical purity (>99%). For radiolabeling application of [ 125 I]1, trans-cyclooctene derived cRGD peptide and human serum albumin were prepared. These substrated were reacted with [ 125 I]1 under mild condition to provide the radiolabeled products [ 125 I]6 and [ 125 I]8, respectively, with excellent radiochemical yields. The biodistribution study of [ 125 I]8 in normal ICR mice showed significantly lower thyroid uptake values than that of 125 I-labeled human serum albumin prepared by a traditional radiolabeling method. Therefore [ 125 I]8 will be a useful radiolabeled tracer in various molecular imaging and biological studies. Those results clearly demonstrate that [ 125 I]1 will be used as a valuable prosthetic group for radiolabeling of biomolecules. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evolution of multispectral aerosol optical properties in a biogenically-influenced urban environment during the CARES campaign

Science.gov (United States)

Gyawali, M.; Arnott, W. P.; Zaveri, R. A.; Song, C.; Pekour, M.; Flowers, B.; Dubey, M. K.; Setyan, A.; Zhang, Q.; Harworth, J. W.; Radney, J. G.; Atkinson, D. B.; China, S.; Mazzoleni, C.; Gorkowski, K.; Subramanian, R.; Jobson, B. T.; Moosmüller, H.

2013-03-01

Ground-based aerosol measurements made in June 2010 within Sacramento urban area (site T0) and at a 40-km downwind location (site T1) in the forested Sierra Nevada foothills area are used to investigate the evolution of multispectral optical properties as the urban aerosols aged and interacted with biogenic emissions. Along with black carbon and non-refractory aerosol mass and composition observations, spectral absorptio (βabs), scattering (βsca), and extinction (βext) coefficients for wavelengths ranging from 355 to 1064 nm were measured at both sites using photoacoustic (PA) instruments with integrating nephelometers and using cavity ring-down (CRD) instruments. The daytime average Ångström exponent of absorption (AEA) was ~1.6 for the wavelength pair 405 and 870 nm at T0, while it was ~1.8 for the wavelength pair 355 and 870 nm at T1, indicating a modest wavelength-dependent enhancement of absorption at both sites throughout the study. The measured and Mie theory calculations of multispectral βsca showed good correlation (R2=0.85-0.94). The average contribution of supermicron aerosol (mainly composed of sea salt particles advected in from the Pacific Ocean) to the total scattering coefficient ranged from less than 20% at 405 nm to greater than 80% at 1064 nm. From 22 to 28 June, secondary organic aerosol mass increased significantly at both sites due to increased biogenic emissions coupled with intense photochemical activity and air mass recirculation in the area. During this period, the short wavelength scattering coefficients at both sites gradually increased due to increase in the size of submicron aerosols. At the same time, BC mass-normalized absorption cross-section (MAC) values for ultraviolet wavelengths at T1 increased by ~60% compared to the relatively less aged urban emissions at the T0 site. In contrast, the average MAC values for 870 nm wavelength were identical at both sites. These results suggest formation of moderately brown secondary

The role of radiolabelled compounds in preclinical drug development

International Nuclear Information System (INIS)

Hawkins, D.R.

1988-01-01

The role of radiolabelled compounds in the development of new drugs is discussed, with particular reference to their use in toxicological, metabolic and pharmacokinetic studies for the pre-clinical safety evaluation of new drugs. (U.K.)

[Nasal submicron emulsion of Scutellariae Radix extract preparation technology research based on phase transfer of solute technology].

Science.gov (United States)

Shi, Ya-jun; Shi, Jun-hui; Chen, Shi-bin; Yang, Ming

2015-07-01

Based on the demand of nasal drug delivery high drug loadings, using the unique phase transfer of solute, integrating the phospholipid complex preparation and submicron emulsion molding process of Scutellariae Radix extract, the study obtained the preparation of the high drug loadings submicron emulsion of Scutellariae Radix extract. In the study of drug solution dispersion method, the uniformity of drug dispersed as the evaluation index, the traditional mixing method, grinding, homogenate and solute phase transfer technology were investigated, and the solute phase transfer technology was adopted in the last. With the adoption of new technology, the drug loading capacity reached 1.33% (phospholipid complex was 4%). The drug loading capacity was improved significantly. The transfer of solute method and timing were studied as follows,join the oil phase when the volume of phospholipid complex anhydrous ethanol solution remaining 30%, the solute phase transfer was completed with the continued recycling of anhydrous ethanol. After drug dissolved away to oil phase, the preparation technology of colostrum was determined with the evaluation index of emulsion droplet form. The particle size of submicron emulsion, PDI and stability parameters were used as evaluation index, orthogonal methodology were adopted to optimize the submicron emulsion ingredient and main influential factors of high pressure homogenization technology. The optimized preparation technology of Scutellariae Radix extract nasal submicron emulsion is practical and stable.

Hot carrier degradation and a new lifetime prediction model in ultra-deep sub-micron pMOSFET

International Nuclear Information System (INIS)

Lei Xiao-Yi; Liu Hong-Xia; Zhang Kai; Zhang Yue; Zheng Xue-Feng; Ma Xiao-Hua; Hao Yue

2013-01-01

The hot carrier effect (HCE) of an ultra-deep sub-micron p-channel metal—oxide semiconductor field-effect transistor (pMOSFET) is investigated in this paper. Experiments indicate that the generation of positively charged interface states is the predominant mechanism in the case of the ultra-deep sub-micron pMOSFET. The relation of the pMOSFET hot carrier degradation to stress time (t), channel width (W), channel length (L), and stress voltage (V d ) is then discussed. Based on the relation, a lifetime prediction model is proposed, which can predict the lifetime of the ultra-deep sub-micron pMOSFET accurately and reflect the influence of the factors on hot carrier degradation directly. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Influence of PEG Stoichiometry on Structure-Tuned Formation of Self-Assembled Submicron Nickel Particles

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Bingxue Pu

2018-01-01

Full Text Available Self-assembled submicron nickel particles were successfully synthesized via the one-step surfactant-assisted solvothermal method. The impact of surfactant and reducing agent stoichiometry is investigated in this manuscript. Different morphologies and structures of Ni particles, including flower-like nanoflakes, hydrangea-like structures, chain structures, sphere-like structures, and hollow structures were prepared through different processing conditions with two parameters such as temperature and time. Based on scanning electron microscopy (SEM, X-ray diffraction (XRD, thermal gravimetric analysis (TGA and vibrating sample magnetometry (VSM, the submicron nickel particles show good saturation magnetization and excellent thermal stabilities with a possible growth mechanism for the variety of the structure-tuned formation. Importantly, the microwave absorption properties of the submicron nickel particles were studied. The lowest reflection loss of Ni-P9/T200/H15 with a thin layer thickness of 1.7 mm can reach −42.6 dB at 17.3 GHz.

Observational evidence for pollution-influenced selective uptake contributing to biogenic secondary organic aerosols in the southeastern U.S.

Science.gov (United States)

Liu, J.; Russell, L. M.; Lee, A. K. Y.; McKinney, K. A.; Surratt, J. D.; Ziemann, P. J.

2017-08-01

During the 2013 Southern Oxidant and Aerosol Study, aerosol mass spectrometer measurements of submicron mass and single particles were taken at Look Rock, Tennessee. Their concentrations increased during multiday stagnation events characterized by low wind, little rain, and increased daytime isoprene emissions. Organic mass (OM) sources were apportioned as 42% "vehicle-related" and 54% biogenic secondary organic aerosol (bSOA), with the latter including "sulfate-related bSOA" that correlated to sulfate (r = 0.72) and "nitrate-related bSOA" that correlated to nitrate (r = 0.65). Single-particle mass spectra showed three composition types that corresponded to the mass-based factors with spectra cosine similarity of 0.93 and time series correlations of r > 0.4. The vehicle-related OM with m/z 44 was correlated to black carbon, "sulfate-related bSOA" was on particles with high sulfate, and "nitrate-related bSOA" was on all particles. The similarity of the m/z spectra (cosine similarity = 0.97) and the time series correlation (r = 0.80) of the "sulfate-related bSOA" to the sulfate-containing single-particle type provide evidence for particle composition contributing to selective uptake of isoprene oxidation products onto particles that contain sulfate from power plants.

Pattern imprinting in deep sub-micron static random access memories induced by total dose irradiation

Science.gov (United States)

Zheng, Qi-Wen; Yu, Xue-Feng; Cui, Jiang-Wei; Guo, Qi; Ren, Di-Yuan; Cong, Zhong-Chao; Zhou, Hang

2014-10-01

Pattern imprinting in deep sub-micron static random access memories (SRAMs) during total dose irradiation is investigated in detail. As the dose accumulates, the data pattern of memory cells loading during irradiation is gradually imprinted on their background data pattern. We build a relationship between the memory cell's static noise margin (SNM) and the background data, and study the influence of irradiation on the probability density function of ΔSNM, which is the difference between two data sides' SNMs, to discuss the reason for pattern imprinting. Finally, we demonstrate that, for micron and deep sub-micron devices, the mechanism of pattern imprinting is the bias-dependent threshold shift of the transistor, but for a deep sub-micron device the shift results from charge trapping in the shallow trench isolation (STI) oxide rather than from the gate oxide of the micron-device.

Towards tumour targeting with copper-radiolabelled macrocycle-antibody conjugates

International Nuclear Information System (INIS)

Morphy, J.R.; Parker, David; Kataky, Ritu

1989-01-01

Tetraaza-macrocycles covalently attached to a monoclonal antibody may be efficiently radiolabelled with 64 Cu or 67 Cu at pH4, minimising non-specific binding to the protein, giving a kinetically stable conjugate in vivo. (author)

Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS) through laboratory studies of inorganic species

Science.gov (United States)

Hu, Weiwei; Campuzano-Jost, Pedro; Day, Douglas A.; Croteau, Philip; Canagaratna, Manjula R.; Jayne, John T.; Worsnop, Douglas R.; Jimenez, Jose L.

2017-08-01

Aerosol mass spectrometers (AMSs) and Aerosol Chemical Speciation Monitors (ACSMs) commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV) that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE) to correct for the loss of particles due to bounce. A new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in the laboratory. Four standard species, NH4NO3, NaNO3, (NH4)2SO4 and NH4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature (Tv ˜ 200-800 °C) on the detected fragments, CE and size distributions are investigated. A Tv of 500-550 °C for the CV is recommended. In the CV, CE was identical (around unity) for more volatile species (e.g. NH4NO3) and comparable to or higher than the SV for less-volatile species (e.g. (NH4)2SO4), demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO3 and SO4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO2(g) from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH4NO3 and comparable to the SV for NaNO3. . We observe an extremely consistent fragmentation for ammonium compared to very large changes for the

Proceedings of submicron multiphase materials

International Nuclear Information System (INIS)

Baney, R.; Gilliom, L.; Hirano, S.I.; Schmidt, H.

1992-01-01

This book contains the papers presented at Symposium R of the spring 1992 Materials Research Society meeting held in San Francisco, California. The title of the symposium, Submicron Multiphase Materials, was selected by the organizers to encompass the realm of composite materials from those smaller than conventional fiber matrix composites to those with phase separation dimensions approaching molecular dimensions. The development of composite materials is as old as the development of materials. Humans quickly learned that, by combining materials, the best properties of each can be realized and that, in fact, synergistic effects often arise. For example, chopped straw was used by the Israelites to limit cracking in bricks. The famed Japanese samurai swords were multilayers of hard oxide and tough ductile materials. One also finds in nature examples of composite materials. These range form bone to wood, consisting of a hard phase which provides strength and stiffness and a softer phase for toughness. Advanced composites are generally thought of as those which are based on a high modulus, discontinuous, chopped or woven fiber phase and a continuous polymer phase. In multiphase composites, dimensions can range from meters in materials such as steel rod-reinforced concrete structures to angstroms. In macrophase separated composite materials, properties frequently follow the rule of mixtures with the properties approximating the arithmetic mean of the properties of each individual phase, if there is good coupling between the phases. As the phases become smaller, the surface to volume ratio grows in importance with respect to properties. Interfacial and interphase phenomena being to dominate. Surface free energies play an ever increasing role in controlling properties. In recent years, much research in materials science has been directed at multiphase systems where phase separations are submicron in at least some dimension

Radiolabeling parameters of {sup 177}Lu-DOTA-RITUXIMAB

Energy Technology Data Exchange (ETDEWEB)

Massicano, Adriana V.F.; Alcarde, Lais F.; Oliveira, Ricardo S.; Mengatti, Jair; Araujo, Elaine B. de, E-mail: adriana.avfernandes@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

Cancer treatment using radioimmunotherapy (RIT) has been the focus of much research in the last two decades. In RIT, a radioisotope is coupled to a monoclonal antibody (mAb) to form a tumor-specific target agent to improve the cytocidal effect of the mAbs. RIT allows the systemic delivery of radiation to disease target by mAbs while sparing normal tissues. Rituximab® (Mabthera - Roche) is a chimeric mouse-human monoclonal antibody; it selectively binds with high affinity to the CD20 antigen, a hydrophobic transmembrane protein, which is expressed on B-lymphocytes and in more than 90% of B cell non-Hodgkin's lymphomas (NHL). The conjugation and radiolabeling process involve special conditions of pH and temperature, long processes of manipulation and mixing. All this process can damage the antibody structure and compromise its clinical application. Therefore, these parameters must be largely studied. The aim of this work was to evaluate the best radiolabeling conditions of DOTA-rituximab. Briefly, 10 mg of antibody previously purified by ultrafiltration device was conjugated with DOTA-NHS-ester (Macrocyclics) in 50 fold molar excess. The reaction was conducted for 1 hour in phosphate buffer pH 8.0 and gently mixing at room temperature, remaining for 24 hours under refrigeration. The immunoconjugated was purified by size exclusion column and ultrafiltration device. The radiolabeled parameters studied were: immunoconjugated mass, activity of {sup 177}LuCl{sub 3}, reaction time, temperature and pH. The radiochemical purity of the preparations was determined using analysis by thin layer chromatography (TLC-SG plates). The best studied condition presented radiochemical purity above 95% and the integrity of antibody was preserved. (author)

Optical Modeling of Sea Salt Aerosols: The Effects of Nonsphericity and Inhomogeneity

Science.gov (United States)

Bi, Lei; Lin, Wushao; Wang, Zheng; Tang, Xiaoyun; Zhang, Xiaoyu; Yi, Bingqi

2018-01-01

The nonsphericity and inhomogeneity of marine aerosols (sea salts) have not been addressed in pertinent radiative transfer calculations and remote sensing studies. This study investigates the optical properties of nonspherical and inhomogeneous sea salts using invariant imbedding T-matrix simulations. Dry sea salt aerosols are modeled based on superellipsoidal geometries with a prescribed aspect ratio and roundness parameter. Wet sea salt particles are modeled as coated superellipsoids, as spherical particles with a superellipsoidal core, and as homogeneous spheres depending on the level of relative humidity. Aspect ratio and roundness parameters are found to be critical to interpreting the linear depolarization ratios (LDRs) of NaCl crystals from laboratory measurements. The optimal morphology parameters of NaCl necessary to reproduce the measurements are found to be consistent with data gleaned from an electron micrograph. The LDRs of wet sea salts are computed based on inhomogeneous models and compared with the measured data from ground-based LiDAR. The dependence of the LDR on relative humidity is explicitly considered. The increase in the LDR with relative humidity at the initial phase of deliquescence is attributed to both the size increase and the inhomogeneity effect. For large humidity values, the LDR substantially decreases because the overall particle shape becomes more spherical and the inhomogeneity effect in a particle on the LDR is suppressed for submicron sea salts. However, the effect of inhomogeneity on optical properties is pronounced for coarse-mode sea salts. These findings have important implications for atmospheric radiative transfer and remote sensing involving sea salt aerosols.

Influence of inspiratory flow rate, particle size, and airway caliber on aerosolized drug delivery to the lung.

Science.gov (United States)

Dolovich, M A

2000-06-01

A number of studies in the literature support the use of fine aerosols of drug, inhaled at low IFRs to target peripheral airways, with the objective of improving clinical responses to inhaled therapy (Fig. 8). Attempts have been made to separate response due to changes in total administered dose or the surface concentration of the dose from response due to changes in site of deposition--both are affected by the particle size of the aerosol, with IFR additionally influencing the latter. The tools for measuring dose and distribution have improved over the last 10-15 years, and thus we should expect greater accuracy in these measurements for assessing drug delivery to the lung. There are still issues, though, in producing radiolabeled (99m)technetium aerosols that are precise markers for the pharmaceutical product being tested and in quantitating absolute doses deposited in the lung. PET isotopes may provide the means for directly labelling a drug and perhaps can offer an alternative for making these measurements in the future, but deposition measurements should not be used in isolation; protocols should incorporate clinical tests to provide parallel therapeutic data in response to inhalation of the drug by the various patient populations being studied.

Towards tumour targeting with copper-radiolabelled macrocycle-antibody conjugates

Energy Technology Data Exchange (ETDEWEB)

Morphy, J.R.; Parker, David; Kataky, Ritu; Harrison, Alice; Walker, Carole; Eaton, M.A.W.; Millican, Andrew; Phipps, Alison

1989-06-15

Tetraaza-macrocycles covalently attached to a monoclonal antibody may be efficiently radiolabelled with /sup 64/Cu or /sup 67/Cu at pH4, minimising non-specific binding to the protein, giving a kinetically stable conjugate in vivo. (author).

Aerosol typing - key information from aerosol studies

Science.gov (United States)

Mona, Lucia; Kahn, Ralph; Papagiannopoulos, Nikolaos; Holzer-Popp, Thomas; Pappalardo, Gelsomina

2016-04-01

Aerosol typing is a key source of aerosol information from ground-based and satellite-borne instruments. Depending on the specific measurement technique, aerosol typing can be used as input for retrievals or represents an output for other applications. Typically aerosol retrievals require some a priori or external aerosol type information. The accuracy of the derived aerosol products strongly depends on the reliability of these assumptions. Different sensors can make use of different aerosol type inputs. A critical review and harmonization of these procedures could significantly reduce related uncertainties. On the other hand, satellite measurements in recent years are providing valuable information about the global distribution of aerosol types, showing for example the main source regions and typical transport paths. Climatological studies of aerosol load at global and regional scales often rely on inferred aerosol type. There is still a high degree of inhomogeneity among satellite aerosol typing schemes, which makes the use different sensor datasets in a consistent way difficult. Knowledge of the 4d aerosol type distribution at these scales is essential for understanding the impact of different aerosol sources on climate, precipitation and air quality. All this information is needed for planning upcoming aerosol emissions policies. The exchange of expertise and the communication among satellite and ground-based measurement communities is fundamental for improving long-term dataset consistency, and for reducing aerosol type distribution uncertainties. Aerosol typing has been recognized as one of its high-priority activities of the AEROSAT (International Satellite Aerosol Science Network, http://aero-sat.org/) initiative. In the AEROSAT framework, a first critical review of aerosol typing procedures has been carried out. The review underlines the high heterogeneity in many aspects: approach, nomenclature, assumed number of components and parameters used for the

Source identification and airborne chemical characterisation of aerosol pollution from long-range transport over Greenland during POLARCAT summer campaign 2008

Science.gov (United States)

Schmale, J.; Schneider, J.; Ancellet, G.; Quennehen, B.; Stohl, A.; Sodemann, H.; Burkhart, J. F.; Hamburger, T.; Arnold, S. R.; Schwarzenboeck, A.; Borrmann, S.; Law, K. S.

2011-10-01

We deployed an aerosol mass spectrometer during the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) summer campaign in Greenland in June/July 2008 on the research aircraft ATR-42. Online size resolved chemical composition data of submicron aerosol were collected up to 7.6 km altitude in the region 60 to 71° N and 40 to 60° W. Biomass burning (BB) and fossil fuel combustion (FF) plumes originating from North America, Asia, Siberia and Europe were sampled. Transport pathways of detected plumes included advection below 700 hPa, air mass uplifting in warm conveyor belts, and high altitude transport in the upper troposphere. By means of the Lagrangian particle dispersion model FLEXPART, trace gas analysis of O3 and CO, particle size distributions and aerosol chemical composition 48 pollution events were identified and classified into five chemically distinct categories. Aerosol from North American BB consisted of 22% particulate sulphate, while with increasing anthropogenic and Asian influence aerosol in Asian FF dominated plumes was composed of up to 37% sulphate category mean value. Overall, it was found that the organic matter fraction was larger (85%) in pollution plumes than for background conditions (71%). Despite different source regions and emission types the particle oxygen to carbon ratio of all plume classes was around 1 indicating low-volatility highly oxygenated aerosol. The volume size distribution of out-of-plume aerosol showed markedly smaller modes than all other distributions with two Aitken mode diameters of 24 and 43 nm and a geometric standard deviation σg of 1.12 and 1.22, respectively, while another very broad mode was found at 490 nm (σg = 2.35). Nearly pure BB particles from North America exhibited an Aitken mode at 66 nm (σg = 1.46) and an accumulation mode diameter of 392 nm (σg = 1.76). An aerosol lifetime, including all processes from emission to

Selective radiolabeling of cell surface proteins to a high specific activity

International Nuclear Information System (INIS)

Thompson, J.A.; Lau, A.L.; Cunningham, D.D.

1987-01-01

A procedure was developed for selective radiolabeling of membrane proteins on cells to higher specific activities than possible with available techniques. Cell surface amino groups were derivatized with 125 I-(hydroxyphenyl)propionyl groups via 125 I-sulfosuccinimidyl (hydroxyphenyl)propionate ( 125 II-sulfo-SHPP). This reagent preferentially labeled membrane proteins exposed at the cell surface of erythrocytes as assessed by the degree of radiolabel incorporation into erythrocyte ghost proteins and hemoglobin. Comparison with the lactoperoxidase-[ 125 I]iodide labeling technique revealed that 125 I-sulfo-SHPP labeled cell surface proteins to a much higher specific activity and hemoglobin to a much lower specific activity. Additionally, this reagent was used for selective radiolabeling of membrane proteins on the cytoplasmic face of the plasma membrane by blocking exofacial amino groups with uniodinated sulfo-SHPP, lysing the cells, and then incubating them with 125 I-sulfo-SHPP. Exclusive labeling of either side of the plasma membrane was demonstrated by the labeling of some marker proteins with well-defined spacial orientations on erythroctyes. Transmembrane proteins such as the epidermal growth factor receptor on cultured cells could also be labeled differentially from either side of the plasma membrane

In vitro and in vivo analysis of radiolabeled clindamycin hydrogel gel by radioscintigraphic techniques

International Nuclear Information System (INIS)

Kumar, N.; Datta, M.; Chopra, M.K.; Soni, N.L.; Mittal, G.; Singh, T.; Bhatnagar, A.; Bhawna

2010-01-01

Full text: Acne is one of the common dermatological problems caused by microorganism Acne vulgaris, therefore being used commonly in the treatment of acne. Clindamycin is the 7- deoxy, 7- chloro congener of the lincomycin, a macrolide antibiotic derived from Streptomyces lincolnensis. This study was performed for in-vitro and in-vivo estimation of radiolabeled clindamycin hydrogel using radioscintigraphic techniques for transdermal permeation. Clindamycin was supplied as a gift sample by Glenmark Research Laboratory (Mumbai, India) and other chemicals and reagents used were of analytical grade and were purchased from Merck Chemicals (India). Clindamycin was radiolabeled with 99m Tc-pertechnetate using stannous chloride as a reducing agent. Radiolabeled clindamycin was characterized for its stability at room temperature and in physiological conditions (serum). Clindamycin hydrogel was prepared by dispersion of radiolabeled clindamycin in carbopol 980 containing polaxomer as surfactant and methyl paraben as preservative solution. The prepared hydrogel was analysed for in vitro analysis via franz diffusion cell and in vivo studies were performed in balb-C mice for biodistribution and skin permeation and were analysed by radiometry. The results obtained showed labeling efficiency of clindamycin was more than 90%, and that was consistent and the radiolabeled drug was stable upto 24 hrs in serum. In vitro release studies showed an increased release rate till four hours and it's become plateaus after 4 hours. In vivo biodistribution studies were showed 99m Tc clindamycin hydrogel remains stable and follow predominantly hepatic excretion. Biodistribution pattern suggests late redistribution from a storage sight, probably, body fats

Analysis of dust and marine aerosol optical depth spectral-curvature information in the UV to SWIR (Short Wave Infrared) wavelength regions.

Science.gov (United States)

O'Neill, N. T.; Smirnov, A.; Eck, T. F.; Sakerin, S.; Kabanov, D.

2005-12-01

Traditional sunphotometry in the UV, visible and very NIR (Near Infrared) spectral regions is weighted, in terms of spectral information content, towards sub-micron (fine mode) particles. Sunphotometry in the NIR and SWIR increases the diversity and information content of spectral aerosol optical depth (AOD) measurements for supermicron (coarse mode) particles. Two data sets representing dust aerosols from the UAE (United Arab Emirates) region and marine aerosols from the northern, tropical and southern Atlantic Ocean were analyzed in terms of their spectral curvature diversity and information content. The former data set was acquired using NIR-enhanced CIMEL sunphotometers (340, 340, 380, 440, 500, 670, 870, 1020, 1640 nm) as part of the August to October, 2004 UAE2 field campaign while the latter data set was acquired using an automated Russian UV to SWIR SP-5 sunphotometer (339, 423, 438, 484, 552, 633, 677, 777, 869, 1241, 1560, 2148, 4000 nm) as part of a October/December 2004 cruise campaign in the northern, tropical and south Atlantic Ocean. A Microtops hand-held sunphotometer was also employed to acquire VIS to NIR AOD spectra during the latter field campaign. Results will be presented in terms of robust micro-physical and spectral curvature parameters which characterize super-micron aerosols and, in a more general sense, in terms of what universal/fundamental optical inferences can be drawn from the two disperse data sets.

An Alternate, Egg-Free Radiolabeled Meal Formulation for Gastric-Emptying Scintigraphy.

Science.gov (United States)

Garrigue, Philippe; Bodin-Hullin, Aurore; Gonzalez, Sandra; Sala, Quentin; Guillet, Benjamin

2017-07-01

Tc-radiolabeled scrambled eggs (SEs) are most often used as the ingested solid phase for gastric-emptying scintigraphy, leading egg-reluctant patients to avoid the examination. We formulated and validated 2 egg-free alternate meals, in the absence of any commercialized formulation: chocolate mug cake (MC) and scrambled tofu (ST). Six healthy volunteers underwent gastric-emptying scintigraphy after ingesting Tc-radiolabeled MC, ST, or SE. Gastric retention indexes did not change significantly between formulations (% of overtime variation to SE: MC 7.75% ± 7.1%, ST 7.17% ± 5.8%; P = 0.6618, not statistically significant), suggesting MC and ST as interesting egg-free alternatives.

Synthesis of fluorine-18 radio-labeled serum albumins for PET blood pool imaging

International Nuclear Information System (INIS)

Basuli, Falguni; Li, Changhui; Xu, Biying; Williams, Mark; Wong, Karen; Coble, Vincent L.; Vasalatiy, Olga; Seidel, Jurgen; Green, Michael V.; Griffiths, Gary L.; Choyke, Peter L.; Jagoda, Elaine M.

2015-01-01

We sought to develop a practical, reproducible and clinically translatable method of radiolabeling serum albumins with fluorine-18 for use as a PET blood pool imaging agent in animals and man. Fluorine-18 radiolabeled fluoronicotinic acid-2,3,5,6-tetrafluorophenyl ester, [ 18 F]F-Py-TFP was prepared first by the reaction of its quaternary ammonium triflate precursor with [ 18 F]tetrabutylammonium fluoride ([ 18 F]TBAF) according to a previously published method for peptides, with minor modifications. The incubation of [ 18 F]F-Py-TFP with rat serum albumin (RSA) in phosphate buffer (pH 9) for 15 min at 37–40 °C produced fluorine-18-radiolabeled RSA and the product was purified using a mini-PD MiniTrap G-25 column. The overall radiochemical yield of the reaction was 18–35% (n = 30, uncorrected) in a 90-min synthesis. This procedure, repeated with human serum albumin (HSA), yielded similar results. Fluorine-18-radiolabeled RSA demonstrated prolonged blood retention (biological half-life of 4.8 hours) in healthy awake rats. The distribution of major organ radioactivity remained relatively unchanged during the 4 hour observation periods either by direct tissue counting or by dynamic PET whole-body imaging except for a gradual accumulation of labeled metabolic products in the bladder. This manual method for synthesizing radiolabeled serum albumins uses fluorine-18, a widely available PET radionuclide, and natural protein available in both pure and recombinant forms which could be scaled up for widespread clinical applications. These preclinical biodistribution and PET imaging results indicate that [ 18 F]RSA is an effective blood pool imaging agent in rats and might, as [ 18 F]HSA, prove similarly useful as a clinical imaging agent

Synthesis of fluorine-18 radio-labeled serum albumins for PET blood pool imaging.

Science.gov (United States)

Basuli, Falguni; Li, Changhui; Xu, Biying; Williams, Mark; Wong, Karen; Coble, Vincent L; Vasalatiy, Olga; Seidel, Jurgen; Green, Michael V; Griffiths, Gary L; Choyke, Peter L; Jagoda, Elaine M

2015-03-01

We sought to develop a practical, reproducible and clinically translatable method of radiolabeling serum albumins with fluorine-18 for use as a PET blood pool imaging agent in animals and man. Fluorine-18 radiolabeled fluoronicotinic acid-2,3,5,6-tetrafluorophenyl ester, [(18)F]F-Py-TFP was prepared first by the reaction of its quaternary ammonium triflate precursor with [(18)F]tetrabutylammonium fluoride ([(18)F]TBAF) according to a previously published method for peptides, with minor modifications. The incubation of [(18)F]F-Py-TFP with rat serum albumin (RSA) in phosphate buffer (pH9) for 15 min at 37-40 °C produced fluorine-18-radiolabeled RSA and the product was purified using a mini-PD MiniTrap G-25 column. The overall radiochemical yield of the reaction was 18-35% (n=30, uncorrected) in a 90-min synthesis. This procedure, repeated with human serum albumin (HSA), yielded similar results. Fluorine-18-radiolabeled RSA demonstrated prolonged blood retention (biological half-life of 4.8 hours) in healthy awake rats. The distribution of major organ radioactivity remained relatively unchanged during the 4 hour observation periods either by direct tissue counting or by dynamic PET whole-body imaging except for a gradual accumulation of labeled metabolic products in the bladder. This manual method for synthesizing radiolabeled serum albumins uses fluorine-18, a widely available PET radionuclide, and natural protein available in both pure and recombinant forms which could be scaled up for widespread clinical applications. These preclinical biodistribution and PET imaging results indicate that [(18)F]RSA is an effective blood pool imaging agent in rats and might, as [(18)F]HSA, prove similarly useful as a clinical imaging agent. Published by Elsevier Inc.

Pattern imprinting in deep sub-micron static random access memories induced by total dose irradiation

International Nuclear Information System (INIS)

Zheng Qi-Wen; Yu Xue-Feng; Cui Jiang-Wei; Guo Qi; Ren Di-Yuan; Cong Zhong-Chao; Zhou Hang

2014-01-01

Pattern imprinting in deep sub-micron static random access memories (SRAMs) during total dose irradiation is investigated in detail. As the dose accumulates, the data pattern of memory cells loading during irradiation is gradually imprinted on their background data pattern. We build a relationship between the memory cell's static noise margin (SNM) and the background data, and study the influence of irradiation on the probability density function of ΔSNM, which is the difference between two data sides' SNMs, to discuss the reason for pattern imprinting. Finally, we demonstrate that, for micron and deep sub-micron devices, the mechanism of pattern imprinting is the bias-dependent threshold shift of the transistor, but for a deep sub-micron device the shift results from charge trapping in the shallow trench isolation (STI) oxide rather than from the gate oxide of the micron-device. (condensed matter: structural, mechanical, and thermal properties)

Breast cancer imaging using radiolabelled somatostatin analogues

International Nuclear Information System (INIS)

Dalm, Simone U.; Melis, Marleen; Emmering, Jasper; Kwekkeboom, Dik J.; Jong, Marion de

2016-01-01

Imaging and therapy using radiolabelled somatostatin analogues are methods successfully used in patients with somatostatin receptor (SSTR)-expressing neuroendocrine tumours. Since these techniques were first introduced, many improvements have been made. SSTR expression has also been reported on breast cancer (BC). Currently mammography, magnetic resonance imaging and ultrasound are the most frequent methods used for BC imaging. Since SSTR expression on BC was demonstrated, clinical studies examining the feasibility of visualizing primary BC using SSTR radioligands have been performed. However, to date SSTR-mediated nuclear imaging is not used clinically in BC patients. The aim of this review is to assess whether recent improvements made within nuclear medicine may enable SSTR-mediated imaging to play a role in BC management. For this we critically analysed results of past studies and discussed the potential of the improvements made within nuclear medicine on SSTR-mediated nuclear imaging of BC. Seven databases were searched for publications on BC imaging with SSTR radioligands. The papers found were analysed by 3 individual observers to identify whether the studies met the pre-set inclusion criteria defined as studies in which nuclear imaging using radiolabelled SST analogues was performed in patients with breast lesions. Twenty-four papers were selected for this review including studies on SSTR-mediated nuclear imaging in BC, neuroendocrine BC and other breast lesions. The analysed studies were heterogeneous with respect to the imaging method, imaging protocol, patient groups and the radiolabelled SST analogues used. Despite the fact that the analysed studies were heterogeneous, sensitivity for primary BC ranged from 36–100%. In a subset of the studies LN lesions were visualized, but sensitivity was lower compared to that for primary tumours. A part of the studies included benign lesions and specificity ranged from 22–100%. Furthermore, false negatives and

Effect of highly radiolabelled 2,4-dinitrochlorobenzene (DNCB) on experimental DNCB contact dermatitis in guinea pigs

Energy Technology Data Exchange (ETDEWEB)

Filipp, G [Red Cross Clinic, Dept. of Clinical Immunology and Allergology, Saarbruecken; Biro, G [2. Medical Clinic, Medical School, University of Saarland, Homburg/Saar; Bahmer, F [Clinic of Dermatology, Medical School, University of Saarland, Homburg/Saar; Mitschke, H [Institute of Pathology, Municipal Academic Hospital, Winterberg, Saarbruecken; Lehmann, G [Dept. of Analytical and Biological Chemistry, University of Saarland, Saarbruecken, Federal Republic of Germany

1984-01-01

With the aid of epicutaneous application of 2,4-dinitrochlorobenzene (DNCB) solution in acetone, we induced a cutaneous allergic reaction of the delayed type. Our question was whether the development of the DNCB cutaneous sensitivity could be suppressed by highly radiolabelled DNCB. On the basis of the clonal selection theory and our own results with other in vivo-experimental animal models, one could suppose that the highly radiolabelled DNCB as haptens binds to the Ig-membrane receptors of the genetically determined T-lymphocyte clone, and that the conjugated radioactivity (/sup 125/I) causes a selective radioactive damage to this competent T-lymphocyte subpopulation. By means of intracardially applied radiolabelled DNCB, we are able to induce either complete or very significant suppression of the cutaneous DNCB immune response. In the second experiment, the highly radiolabelled DNCB was not able to inhibit sensitization to a simultaneously applied 4-ethoxy-methylene-2-phenyl-oxazolone (oxazolone). This result clearly demonstrates the antigen specificity of this form of immune suppression.

Effect of highly radiolabelled 2,4-dinitrochlorobenzene (DNCB) on experimental DNCB contact dermatitis in guinea pigs

International Nuclear Information System (INIS)

Filipp, G.; Biro, G.; Bahmer, F.; Mitschke, H.; Lehmann, G.

1984-01-01

With the aid of epicutaneous application of 2,4-dinitrochlorobenzene (DNCB) solution in acetone, we induced a cutaneous allergic reaction of the delayed type. Our question was whether the development of the DNCB cutaneous sensitivity could be suppressed by highly radiolabelled DNCB. On the basis of the clonal selection theory and our own results with other in vivo-experimental animal models, one could suppose that the highly radiolabelled DNCB as haptens binds to the Ig-membrane receptors of the genetically determined T-lymphocyte clone, and that the conjugated radioactivity ( 125 I) causes a selective radioactive damage to this competent T-lymphocyte subpopulation. By means of intracardially applied radiolabelled DNCB, we are able to induce either complete or very significant suppression of the cutaneous DNCB immune response. In the second experiment, the highly radiolabelled DNCB was not able to inhibit sensitization to a simultaneously applied 4-ethoxy-methylene-2-phenyl-oxazolone (oxazolone). This result clearly demonstrates the antigen specificity of this form of immune suppression. (author)

Hot-carrier effects on irradiated deep submicron NMOSFET

International Nuclear Information System (INIS)

Cui Jiangwei; Zheng Qiwen; Yu Xuefeng; Cong Zhongchao; Zhou Hang; Guo Qi; Wen Lin; Wei Ying; Ren Diyuan

2014-01-01

We investigate how γ exposure impacts the hot-carrier degradation in deep submicron NMOSFET with different technologies and device geometries for the first time. The results show that hot-carrier degradations on irradiated devices are greater than those without irradiation, especially for narrow channel device. The reason is attributed to charge traps in STI, which then induce different electric field and impact ionization rates during hot-carrier stress. (semiconductor devices)

Chemical composition, microstructure, and hygroscopic properties of aerosol particles at the Zotino Tall Tower Observatory (ZOTTO), Siberia, during a summer campaign

Science.gov (United States)

Mikhailov, E. F.; Mironov, G. N.; Pöhlker, C.; Chi, X.; Krüger, M. L.; Shiraiwa, M.; Förster, J.-D.; Pöschl, U.; Vlasenko, S. S.; Ryshkevich, T. I.; Weigand, M.; Kilcoyne, A. L. D.; Andreae, M. O.

2015-08-01

In this study we describe the hygroscopic properties of accumulation- and coarse-mode aerosol particles sampled at the Zotino Tall Tower Observatory (ZOTTO) in central Siberia (61° N, 89° E) from 16 to 21 June 2013. The hygroscopic growth measurements were supplemented with chemical analyses of the samples, including inorganic ions and organic/elemental carbon. In addition, the microstructure and chemical compositions of aerosol particles were analyzed by x-ray micro-spectroscopy (STXM-NEXAFS) and transmission electron microscopy (TEM). A mass closure analysis indicates that organic carbon accounted for 61 and 38 % of particulate matter (PM) in the accumulation mode and coarse mode, respectively. The water-soluble fraction of organic matter was estimated to be 52 and 8 % of PM in these modes. Sulfate, predominantly in the form of ammoniated sulfate, was the dominant inorganic component in both size modes: ~ 34 % in the accumulation mode vs. ~ 47 % in the coarse mode. The hygroscopic growth measurements were conducted with a filter-based differential hygroscopicity analyzer (FDHA) over the range of 5-99.4 % RH in the hydration and dehydration operation modes. The FDHA study indicates that both accumulation and coarse modes exhibit pronounced water uptake approximately at the same relative humidity (RH), starting at ~ 70 %, while efflorescence occurred at different humidities, i.e., at ~ 35 % RH for submicron particles vs. ~ 50 % RH for supermicron particles. This ~ 15 % RH difference was attributed to higher content of organic material in the submicron particles, which suppresses water release in the dehydration experiments. The kappa mass interaction model (KIM) was applied to characterize and parameterize non-ideal solution behavior and concentration-dependent water uptake by atmospheric aerosol samples in the 5-99.4 % RH range. Based on KIM, the volume-based hygroscopicity parameter, κv, was calculated. The κv,ws value related to the water-soluble (ws

Characteristics and Composition of Atmospheric Aerosols in Phimai, Central Thailand During BASE-ASIA

Science.gov (United States)

Li, Can; Tsay, Si-Chee; Hsu, N. Christina; Kim, Jin Young; Howell, Steven G.; Huebert, Barry J.; Ji, Qiang; Jeong, Myeong-Jae; Wang, Sheng-Hsiang; Hansell, Richard A.;

Assessment of Sub-Micron Particles by Exploiting Charge Differences with Dielectrophoresis

Directory of Open Access Journals (Sweden)

Maria F. Romero-Creel

2017-08-01

Full Text Available The analysis, separation, and enrichment of submicron particles are critical steps in many applications, ranging from bio-sensing to disease diagnostics. Microfluidic electrokinetic techniques, such as dielectrophoresis (DEP have proved to be excellent platforms for assessment of submicron particles. DEP is the motion of polarizable particles under the presence of a non-uniform electric field. In this work, the polarization and dielectrophoretic behavior of polystyrene particles with diameters ranging for 100 nm to 1 μm were studied employing microchannels for insulator based DEP (iDEP and low frequency (<1000 Hz AC and DC electric potentials. In particular, the effects of particle surface charge, in terms of magnitude and type of functionalization, were examined. It was found that the magnitude of particle surface charge has a significant impact on the polarization and dielectrophoretic response of the particles, allowing for successful particle assessment. Traditionally, charge differences are exploited employing electrophoretic techniques and particle separation is achieved by differential migration. The present study demonstrates that differences in the particle’s surface charge can also be exploited by means of iDEP; and that distinct types of nanoparticles can be identified by their polarization and dielectrophoretic behavior. These findings open the possibility for iDEP to be employed as a technique for the analysis of submicron biological particles, where subtle differences in surface charge could allow for rapid particle identification and separation.

Wintertime aerosol chemical composition and source apportionment of the organic fraction in the metropolitan area of Paris

Directory of Open Access Journals (Sweden)

M. Crippa

2013-01-01

Full Text Available The effect of a post-industrial megacity on local and regional air quality was assessed via a month-long field measurement campaign in the Paris metropolitan area during winter 2010. Here we present source apportionment results from three aerosol mass spectrometers and two aethalometers deployed at three measurement stations within the Paris region. Submicron aerosol composition is dominated by the organic fraction (30–36% and nitrate (28–29%, with lower contributions from sulfate (14–16%, ammonium (12–14% and black carbon (7–13%.

Organic source apportionment was performed using positive matrix factorization, resulting in a set of organic factors corresponding both to primary emission sources and secondary production. The dominant primary sources are traffic (11–15% of organic mass, biomass burning (13–15% and cooking (up to 35% during meal hours. Secondary organic aerosol contributes more than 50% to the total organic mass and includes a highly oxidized factor from indeterminate and/or diverse sources and a less oxidized factor related to wood burning emissions. Black carbon was apportioned to traffic and wood burning sources using a model based on wavelength-dependent light absorption of these two combustion sources. The time series of organic and black carbon factors from related sources were strongly correlated. The similarities in aerosol composition, total mass and temporal variation between the three sites suggest that particulate pollution in Paris is dominated by regional factors, and that the emissions from Paris itself have a relatively low impact on its surroundings.

Evidence of a reduction in cloud condensation nuclei activity of water-soluble aerosols caused by biogenic emissions in a cool-temperate forest.

Science.gov (United States)

Müller, Astrid; Miyazaki, Yuzo; Tachibana, Eri; Kawamura, Kimitaka; Hiura, Tsutom

2017-08-16

Biogenic organic aerosols can affect cloud condensation nuclei (CCN) properties, and subsequently impact climate change. Large uncertainties exist in how the difference in the types of terrestrial biogenic sources and the abundance of organics relative to sulfate affect CCN properties. For the submicron water-soluble aerosols collected for two years in a cool-temperate forest in northern Japan, we show that the hygroscopicity parameter κ CCN (0.44 ± 0.07) exhibited a distinct seasonal trend with a minimum in autumn (κ CCN  = 0.32-0.37); these κ CCN values were generally larger than that of ambient particles, including water-insoluble fractions. The temporal variability of κ CCN was controlled by the water-soluble organic matter (WSOM)-to-sulfate ratio (R 2  > 0.60), where the significant reduction of κ CCN in autumn was linked to the increased WSOM/sulfate ratio. Positive matrix factorization analysis indicates that α-pinene-derived secondary organic aerosol (SOA) substantially contributed to the WSOM mass (~75%) in autumn, the majority of which was attributable to emissions from litter/soil microbial activity near the forest floor. These findings suggest that WSOM, most likely α-pinene SOA, originated from the forest floor can significantly suppress the aerosol CCN activity in cool-temperate forests, which have implications for predicting climate effects by changes in biogenic emissions in future.

Radiolabeled microsphere measurements of alveolar bone blood flow in dogs

International Nuclear Information System (INIS)

Kaplan, M.L.; Jeffcoat, M.K.; Goldhaber, P.

1978-01-01

Radiolabeled microspheres were injected into the left cardiac ventricle in healthy adult dogs to quantify blood in maxillary and mandibular alveolar bone. Heart rate, arterial blood pressure and pulse contour were monitored throughout each experiment. Blood flow in maxillary alveolar bone was more than 30 % greater (p<.001) than in mandibular alveolar bone. Alveolar bone blood flow (mean +- S.D.) measured as ml/min per gram was 0.12 +- .02 in the maxilla compared to 0.09 +- .02 in the mandible. The cardiovascular parameters monitored were constant immediately prior to the injection of microspheres and remained unchanged during and following injection. It is possible that radiolabeled microspheres can be used to quantify the circulatory changes in alveolar bone during the development of destructive periodontal disease in dogs. (author)

Aerosol composition, oxidative properties, and sources in Beijing: results from the 2014 Asia-Pacific Economic Cooperation Summit study

Science.gov (United States)

Xu, W. Q.; Sun, Y. L.; Chen, C.; Du, W.; Han, T. T.; Wang, Q. Q.; Fu, P. Q.; Wang, Z. F.; Zhao, X. J.; Zhou, L. B.; Ji, D. S.; Wang, P. C.; Worsnop, D. R.

2015-08-01

The mitigation of air pollution in megacities remains a great challenge because of the complex sources and formation mechanisms of aerosol particles. The 2014 Asia- Pacific Economic Cooperation (APEC) summit in Beijing serves as a unique experiment to study the impacts of emission controls on aerosol composition, size distributions, and oxidative properties. Herein, a high-resolution time-of-flight aerosol mass spectrometer was deployed in urban Beijing for real-time measurements of size-resolved non-refractory submicron aerosol (NR-PM1) species from 14 October to 12 November 2014, along with a range of collocated measurements. The average (±σ) PM1 was 41.6 (±38.9) μg m-3 during APEC, which was decreased by 53 % compared with that before APEC. The aerosol composition showed substantial changes owing to emission controls during APEC. Secondary inorganic aerosols (SIA = sulfate + nitrate + ammonium) showed significant reductions of 62-69 %, whereas organics presented much smaller decreases (35 %). The results from the positive matrix factorization of organic aerosols (OA) indicated that highly oxidized secondary OA (SOA) showed decreases similar to those of SIA during APEC. However, primary OA (POA) from cooking, traffic, and biomass burning sources were comparable to those before APEC, indicating the presence of strong local source emissions. The oxidation properties showed corresponding changes in response to OA composition. The average oxygen-to-carbon level during APEC was 0.36 (±0.10), which is lower than the 0.43 (±0.13) measured before APEC, demonstrating a decrease in the OA oxidation degree. The changes in size distributions of primary and secondary species varied during APEC. SIA and SOA showed significant reductions in large accumulation modes with peak diameters shifting from ~ 650 to 400 nm during APEC, whereas those of POA remained relatively unchanged. The changes in aerosol composition, size distributions, and oxidation degrees during the aging

Monitoring radiolabelled antacid preparations in the stomach

International Nuclear Information System (INIS)

May, H.A.; Wilson, C.G.; Hardy, J.G.

1984-01-01

Radiolabelled antacid preparations have been monitored in the stomach using gamma scintigraphy. The stomach contents were labelled with technetium-99m and two antacid preparations with indium-113m. It has been shown that the antacid containing aluminium hydroxide and magnesium oxide mixed and emptied with the other stomach contents. An alginate containing preparation tended to float on the food and emptied only slowly from the stomach. (Auth.)

Current status and future perspectives of in vivo small animal imaging using radiolabeled nanoparticles

International Nuclear Information System (INIS)

Loudos, George; Kagadis, George C.; Psimadas, Dimitris

2011-01-01

Small animal molecular imaging is a rapidly expanding efficient tool to study biological processes non-invasively. The use of radiolabeled tracers provides non-destructive, imaging information, allowing time related phenomena to be repeatedly studied in a single animal. In the last decade there has been an enormous progress in related technologies and a number of dedicated imaging systems overcome the limitations that the size of small animal possesses. On the other hand, nanoparticles (NPs) gain increased interest, due to their unique properties, which make them perfect candidates for biological applications. Over the past 5 years the two fields seem to cross more and more often; radiolabeled NPs have been assessed in numerous pre-clinical studies that range from oncology, till HIV treatment. In this article the current status in the tools, applications and trends of radiolabeled NPs reviewed.

A Facile Method for Separating and Enriching Nano and Submicron Particles from Titanium Dioxide Found in Food and Pharmaceutical Products

Science.gov (United States)

Yang, Yu; Capco, David G.; Westerhoff, Paul

2016-01-01

Recent studies indicate the presence of nano-scale titanium dioxide (TiO2) as an additive in human foodstuffs, but a practical protocol to isolate and separate nano-fractions from soluble foodstuffs as a source of material remains elusive. As such, we developed a method for separating the nano and submicron fractions found in commercial-grade TiO2 (E171) and E171 extracted from soluble foodstuffs and pharmaceutical products (e.g., chewing gum, pain reliever, and allergy medicine). Primary particle analysis of commercial-grade E171 indicated that 54% of particles were nano-sized (i.e., < 100 nm). Isolation and primary particle analysis of five consumer goods intended to be ingested revealed differences in the percent of nano-sized particles from 32%‒58%. Separation and enrichment of nano- and submicron-sized particles from commercial-grade E171 and E171 isolated from foodstuffs and pharmaceuticals was accomplished using rate-zonal centrifugation. Commercial-grade E171 was separated into nano- and submicron-enriched fractions consisting of a nano:submicron fraction of approximately 0.45:1 and 3.2:1, respectively. E171 extracted from gum had nano:submicron fractions of 1.4:1 and 0.19:1 for nano- and submicron-enriched, respectively. We show a difference in particle adhesion to the cell surface, which was found to be dependent on particle size and epithelial orientation. Finally, we provide evidence that E171 particles are not immediately cytotoxic to the Caco-2 human intestinal epithelium model. These data suggest that this separation method is appropriate for studies interested in isolating the nano-sized particle fraction taken directly from consumer products, in order to study separately the effects of nano and submicron particles. PMID:27798677

A Facile Method for Separating and Enriching Nano and Submicron Particles from Titanium Dioxide Found in Food and Pharmaceutical Products.

Science.gov (United States)

Faust, James J; Doudrick, Kyle; Yang, Yu; Capco, David G; Westerhoff, Paul

2016-01-01

Recent studies indicate the presence of nano-scale titanium dioxide (TiO2) as an additive in human foodstuffs, but a practical protocol to isolate and separate nano-fractions from soluble foodstuffs as a source of material remains elusive. As such, we developed a method for separating the nano and submicron fractions found in commercial-grade TiO2 (E171) and E171 extracted from soluble foodstuffs and pharmaceutical products (e.g., chewing gum, pain reliever, and allergy medicine). Primary particle analysis of commercial-grade E171 indicated that 54% of particles were nano-sized (i.e., E171 and E171 isolated from foodstuffs and pharmaceuticals was accomplished using rate-zonal centrifugation. Commercial-grade E171 was separated into nano- and submicron-enriched fractions consisting of a nano:submicron fraction of approximately 0.45:1 and 3.2:1, respectively. E171 extracted from gum had nano:submicron fractions of 1.4:1 and 0.19:1 for nano- and submicron-enriched, respectively. We show a difference in particle adhesion to the cell surface, which was found to be dependent on particle size and epithelial orientation. Finally, we provide evidence that E171 particles are not immediately cytotoxic to the Caco-2 human intestinal epithelium model. These data suggest that this separation method is appropriate for studies interested in isolating the nano-sized particle fraction taken directly from consumer products, in order to study separately the effects of nano and submicron particles.

Long-range transport biomass burning emissions to the Himalayas: insights from high-resolution aerosol mass spectrometer

Science.gov (United States)

Xu, J.; Zhang, X.; Liu, Y.; Shichang, K.; Ma, Y.

2017-12-01

An intensive measurement was conducted at a remote, background, and high-altitude site (Qomolangma station, QOMS, 4276 m a.s.l.) in the northern Himalayas, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) along with other collocated instruments. The field measurement was performed from April 12 to May 12, 2016 to chemically characterize high time-resolved submicron particulate matter (PM1) and obtain the influence of biomass burning emissions to the Himalayas, frequently transported from south Asia during pre-monsoon season. Two high aerosol loading periods were observed during the study. Overall, the average (± 1σ) PM1 mass concentration was 4.44 (± 4.54) µg m-3 for the entire study, comparable with those observed at other remote sites worldwide. Organic aerosols (OA) was the dominant PM1 species (accounting for 54.3% of total PM1 mass on average) and its contribution increased with the increase of total PM1 mass loading. The average size distributions of PM1 species all peaked at an overlapping accumulation mode ( 500 nm), suggesting that aerosol particles were internally well-mixed and aged during long-range transportations. Positive matrix factorization (PMF) analysis on the high-resolution organic mass spectra identified three distinct OA factors, including a biomass burning related OA (BBOA, 43.7%) and two oxygenated OA (Local-OOA and LRT-OOA; 13.9% and 42.4%) represented sources from local emissions and long-range transportations, respectively. Two polluted air mass origins (generally from the west and southwest of QOMS) and two polluted episodes with enhanced PM1 mass loadings and elevated BBOA contributions were observed, respectively, suggesting the important sources of wildfires from south Asia. One of polluted aerosol plumes was investigated in detail to illustrate the evolution of aerosol characteristics at QOMS driving by different impacts of wildfires, air mass origins, meteorological conditions and

Aerosol transport and wet scavenging in deep convective clouds: a case study and model evaluation using a multiple passive tracer analysis approach

Energy Technology Data Exchange (ETDEWEB)

Yang, Qing; Easter, Richard C.; Campuzano-Jost, Pedro; Jimenez, Jose L.; Fast, Jerome D.; Ghan, Steven J.; Wang, Hailong; Berg, Larry K.; Barth, Mary; Liu, Ying; Shrivastava, ManishKumar B.; Singh, Balwinder; Morrison, H.; Fan, Jiwen; Ziegler, Conrad L.; Bela, Megan; Apel, Eric; Diskin, G. S.; Mikoviny, Tomas; Wisthaler, Armin

2015-08-20

The effect of wet scavenging on ambient aerosols in deep, continental convective clouds in the mid-latitudes is studied for a severe storm case in Oklahoma during the Deep Convective Clouds and Chemistry (DC3) field campaign. A new passive-tracer based transport analysis framework is developed to characterize the convective transport based on the vertical distribution of several slowly reacting and nearly insoluble trace gases. The passive gas concentration in the upper troposphere convective outflow results from a mixture of 47% from the lower level (0-3 km), 21% entrained from the upper troposphere, and 32% from mid-atmosphere based on observations. The transport analysis framework is applied to aerosols to estimate aerosol transport and wet-scavenging efficiency. Observations yield high overall scavenging efficiencies of 81% and 68% for aerosol mass (Dp < 1μm) and aerosol number (0.03< Dp < 2.5μm), respectively. Little chemical selectivity to wet scavenging is seen among observed submicron sulfate (84%), organic (82%), and ammonium (80%) aerosols, while nitrate has a much lower scavenging efficiency of 57% likely due to the uptake of nitric acid. Observed larger size particles (0.15 - 2.5μm) are scavenged more efficiently (84%) than smaller particles (64%; 0.03 - 0.15μm). The storm is simulated using the chemistry version of the WRF model. Compared to the observation based analysis, the standard model underestimates the wet scavenging efficiency for both mass and number concentrations with low biases of 31% and 40%, respectively. Adding a new treatment of secondary activation significantly improves simulation results, so that the bias in scavenging efficiency in mass and number concentrations is reduced to <10%. This supports the hypothesis that secondary activation is an important process for wet removal of aerosols in deep convective storms.

Deep sub-micron FD-SOI for front-end application

International Nuclear Information System (INIS)

Ikeda, H.; Arai, Y.; Hara, K.; Hayakawa, H.; Hirose, K.; Ikegami, Y.; Ishino, H.; Kasaba, Y.; Kawasaki, T.; Kohriki, T.; Martin, E.; Miyake, H.; Mochizuki, A.; Tajima, H.; Tajima, O.; Takahashi, T.; Takashima, T.; Terada, S.; Tomita, H.; Tsuboyama, T.

2007-01-01

In order to confirm benefits of a deep sub-micron FD-SOI and to identify possible issues concerning front-end circuits with the FD-SOI, we have submitted a small design to Oki Electric Industry Co., Ltd. via the multi-chip project service of VDEC, the University of Tokyo. The initial test results and future plans for development are presented

Distribution and pharmacokinetics of radiolabeled monoclonal antibody OC 125 after intravenous and intraperitoneal administration in gynecologic tumors

International Nuclear Information System (INIS)

Haisma, H.J.; Moseley, K.R.; Battaile, A.; Griffiths, T.C.; Knapp, R.C.

1988-01-01

Radiolabeled monoclonal antibodies may be useful for radioimmunotherapy of gynecologic tumors. Iodine 131-labeled F(ab')2 fragments of a monoclonal antibody, OC 125, with specificity for ovarian carcinoma, were used to study the distribution and pharmacokinetics of this antibody in patients with gynecologic tumors. The radiolabeled antibody was injected intravenously or intraperitoneally into 10 patients suspected of having ovarian cancer. Blood and urine samples were used for pharmacokinetic studies, and biopsy specimens were examined for the uptake of antibody. The serum half-life of the labeled antibody was 30 hours after intravenous administration, with 20% of the injected dose per liter detected at 24 hours. After intraperitoneal injection, the appearance of antibody in serum was slow, with a maximum level of 1.4% of the injected dose per liter at 24 hours. Urinary excretion of the radiolabeled antibody was similar for intravenous and intraperitoneal administration, with approximately 50% of the injected dose excreted after 48 hours. Intraperitoneal administration of the radiolabeled antibody resulted in a higher uptake of antibody in the tumor and a lower uptake of antibody in normal tissues. On the basis of this limited study, intraperitoneal administration of radiolabeled antibody is preferred over intravenous administration for radioimmunotherapy of ovarian cancer

Submicron-bubble-enhanced focused ultrasound for blood-brain barrier disruption and improved CNS drug delivery.

Directory of Open Access Journals (Sweden)

Ching-Hsiang Fan

Full Text Available The use of focused ultrasound (FUS with microbubbles has been proven to induce transient blood-brain barrier opening (BBB-opening. However, FUS-induced inertial cavitation of microbubbles can also result in erythrocyte extravasations. Here we investigated whether induction of submicron bubbles to oscillate at their resonant frequency would reduce inertial cavitation during BBB-opening and thereby eliminate erythrocyte extravasations in a rat brain model. FUS was delivered with acoustic pressures of 0.1-4.5 MPa using either in-house manufactured submicron bubbles or standard SonoVue microbubbles. Wideband and subharmonic emissions from bubbles were used to quantify inertial and stable cavitation, respectively. Erythrocyte extravasations were evaluated by in vivo post-treatment magnetic resonance susceptibility-weighted imaging, and finally by histological confirmation. We found that excitation of submicron bubbles with resonant frequency-matched FUS (10 MHz can greatly limit inertial cavitation while enhancing stable cavitation. The BBB-opening was mainly caused by stable cavitation, whereas the erythrocyte extravasation was closely correlated with inertial cavitation. Our technique allows extensive reduction of inertial cavitation to induce safe BBB-opening. Furthermore, the safety issue of BBB-opening was not compromised by prolonging FUS exposure time, and the local drug concentrations in the brain tissues were significantly improved to 60 times (BCNU; 18.6 µg versus 0.3 µg by using chemotherapeutic agent-loaded submicron bubbles with FUS. This study provides important information towards the goal of successfully translating FUS brain drug delivery into clinical use.

Radiolabelling of antibodies with indium: Use of diethylenetriaminepentaacetic acid (DTPA) as chelating agent

International Nuclear Information System (INIS)

Loetscher, H.

1986-01-01

/sup 111/In/sup 3+/ was used to radiolabel the F(ab')/sub 2/ fragment of a monoclonal antibody (b-12) raised against a surface antigen of a mammalian breast tumor cell line (5). The in vivo distribution of the radiolabel was analyzed in mice bearing a transplant of fixed tumor cells in the left thigh. The results demonstrate that DTPA can be efficiently coupled to a tumor specific F(ab')/sub 2/ fragment and loaded with /sup 111/In/sup 3+/ yielding a stable, highly labelled complex

Physical properties and concentration of aerosol particles over the Amazon tropical forest during background and biomass burning conditions

Directory of Open Access Journals (Sweden)

P. Guyon

2003-01-01

Full Text Available We investigated the size distribution, scattering and absorption properties of Amazonian aerosols and the optical thickness of the aerosol layer under the pristine background conditions typical of the wet season, as well as during the biomass-burning-influenced dry season. The measurements were made during two campaigns in 1999 as part of the European contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA-EUSTACH. In moving from the wet to the dry season, median particle numbers were observed to increase from values comparable to those of the remote marine boundary layer (~400 cm-3 to values more commonly associated with urban smog (~4000 cm-3, due to a massive injection of submicron smoke particles. Aerosol optical depths at 500 nm increased from 0.05 to 0.8 on average, reaching a value of 2 during the dry season. Scattering and absorption coefficients, measured at 550 nm, showed a concomitant increase from average values of 6.8 and 0.4 Mm-1 to values of 91 and 10 Mm-1, respectively, corresponding to an estimated decrease in single-scattering albedo from ca. 0.97 to 0.91. The roughly tenfold increase in many of the measured parameters attests to the dramatic effect that extensive seasonal biomass burning (deforestation, pasture cleaning is having on the composition and properties of aerosols over Amazonia. The potential exists for these changes to impact on regional and global climate through changes to the extinction of solar radiation as well as the alteration of cloud properties.

Fabrication of magnetic and fluorescent chitin and dibutyrylchitin sub-micron particles by oil-in-water emulsification.

Science.gov (United States)

Blanco-Fernandez, Barbara; Chakravarty, Shatadru; Nkansah, Michael K; Shapiro, Erik M

2016-11-01

Chitin is a carbohydrate polymer with unique pharmacological and immunological properties, however, because of its unwieldy chemistry, the synthesis of discreet sized sub-micron particles has not been well reported. This work describes a facile and flexible method to fabricate biocompatible chitin and dibutyrylchitin sub-micron particles. This technique is based on an oil-in-water emulsification/evaporation method and involves the hydrophobization of chitin by the addition of labile butyryl groups onto chitin, disrupting intermolecular hydrogen bonds and enabling solubility in the organic solvent used as the oil phase during fabrication. The subsequent removal of butyryl groups post-fabrication through alkaline saponification regenerates native chitin while keeping particles morphology intact. Examples of encapsulation of hydrophobic dyes and nanocrystals are demonstrated, specifically using iron oxide nanocrystals and coumarin 6. The prepared particles had diameters between 300-400nm for dibutyrylchitin and 500-600nm for chitin and were highly cytocompatible. Moreover, they were able to encapsulate high amounts of iron oxide nanocrystals and were able to label mammalian cells. We describe a technique to prepare sub-micron particles of highly acetylated chitin (>90%) and dibutyrylchitin and demonstrate their utility as carriers for imaging. Chitin is a polysaccharide capable of stimulating the immune system, a property that depends on the acetamide groups, but its insolubility limits its use. No method for sub-micron particle preparation with highly acetylated chitins have been published. The only approach for the preparation of sub-micron particles uses low acetylation chitins. Dibutyrylchitin, a soluble chitin derivative, was used to prepare particles by oil in water emulsification. Butyryl groups were then removed, forming chitin particles. These particles could be suitable for encapsulation of hydrophobic payloads for drug delivery and cell imaging, as well as

Predicting the biodistribution of radiolabeled cMORF effector in MORF-pretargeted mice

International Nuclear Information System (INIS)

Liu, Guozheng; Dou, Shuping; He, Jiang; Liu, Xinrong; Rusckowski, Mary; Hnatowich, Donald J.

2007-01-01

Pretargeting with phosphorodiamidate morpholino oligomers (MORFs) involves administration of a MORF-conjugated anti-tumor antibody such as MN14 as a pretargeting agent before that of the radiolabeled complementary MORF (cMORF) as the effector. The dosages of the pretargeting agent and effector, the pretargeting interval, and the detection time are the four pretargeting variables. The goal of this study was to develop a semiempirical description capable of predicting the biodistribution of the radiolabeled effector in pretargeted mice and then to compare predictions with experimental results from pretargeting studies in tumored animals in which the pretargeting interval and the detection time were both fixed but the dosages of both the effector and the pretargeting agent were separately varied. Pretargeting studies in LS174T tumored mice were performed using the anti-CEA antibody MN14 conjugated with MORF and the cMORF radiolabeled with 99m Tc. A description was developed based on our previous observations in the same mouse model of the blood and tumor levels of MORF-MN14, accessibility of MORF-MN14 to labeled cMORF, the tumor accumulation of labeled cMORF relative to MORF-MN14 levels therein, and the kidney accumulation of labeled cMORF. The predicted values were then compared with the experimental values. The predicted biodistribution of the radiolabeled effector and the experimental data were in gratifying agreement in normal organs, suggesting that the description of the pretargeting process was reliable. The tumor accumulations occasionally fell outside two standard deviations of that predicted, but after tumor size correction, good agreement between predicted and experimental values was observed here as well. A semiempirical description of the biodistribution of labeled cMORF was capable of predicting the biodistribution of the radiolabeled effector in the pretargeted tumored mouse model, demonstrating that the underlying pretargeting concepts are correct. We

Characteristics of scandate-impregnated cathodes with sub-micron scandia-doped matrices

International Nuclear Information System (INIS)

Yuan Haiqing; Gu Xin; Pan Kexin; Wang Yiman; Liu Wei; Zhang Ke; Wang Jinshu; Zhou Meiling; Li Ji

2005-01-01

We describe in this paper scandate-impregnated cathodes with sub-micron scandia-doped tungsten matrices having an improved uniformity of the Sc distribution. The scandia-doped tungsten powders were made by both liquid-solid doping and liquid-liquid doping methods on the basis of previous research. By improving pressing, sintering and impregnating procedures, we have obtained scandate-impregnated cathodes with a good uniformity of the Sc 2 O 3 - distribution. The porosity of the sub-micron structure matrix and content of impregnants inside the matrix are similar to those of conventionally impregnated cathodes. Space charge limited current densities of more than 30 A/cm 2 at 850 deg. C b have been obtained in a reproducible way. The current density continuously increases during the first 2000 h life test at 950 deg. C b with a dc load of 2 A/cm 2 and are stable for at least 3000 h

Sintering mantle mineral aggregates with submicron grains: examples of olivine and clinopyroxene

Science.gov (United States)

Tsubokawa, Y.; Ishikawa, M.

2017-12-01

Physical property of the major mantle minerals play an important role in the dynamic behavior of the Earth's mantle. Recently, it has been found that nano- to sub-micron scale frictional processes might control faulting processes and earthquake instability, and ultrafine-grained mineral aggregates thus have attracted the growing interest. Here we investigated a method for preparing polycrystalline clinoyproxene and polycrystalline olivine with grain size of sub-micron scale from natural crystals, two main constituents of the upper mantle. Nano-sized powders of both minerals are sintered under argon flow at temperatures ranging from 1130-1350 °C for 0.5-20 h. After sintering at 1180 °C and 1300 °C, we successfully fabricated polycrystalline clinopyroxene and polycrystalline olivine with grain size of physical properties of Earth's mantle.

Anti-CD20 Immunoglobulin G Radiolabeling with a 99mTc-Tricarbonyl Core: In Vitro and In Vivo Evaluations.

Directory of Open Access Journals (Sweden)

Hélène Carpenet

Full Text Available In recent years, the diagnostic and therapeutic uses of radioisotopes have shown significant progress. Immunoglobulin (Ig appears to be a promising tracer, particularly due to its ability to target selected antigens. The main objective of this study is to optimize and assess an Ig radiolabeling method with Technetium 99m (99mTc, an attractive radioelement used widely for diagnostic imaging. Monoclonal anti-CD20 IgG was retained to study in vitro and in vivo radiolabeling impact. After IgG derivatization with 2-iminothiolane, IgG-SH was radiolabeled by an indirect method, using a 99mTc-tricarbonyl core. Radiolabeling stability was evaluated over 24h by thin-layer chromatography. IgG integrity was checked by sodium dodecyl sulfate-polyacrylamide gel electrophoresis coupled with Western blot and autoradiography. The radiolabeled Ig's immunoaffinity was assessed in vitro by a radioimmunoassay method and binding experiments with cells (EL4-hCD20 and EL4-WT. Biodistribution studies were performed in normal BALB/c mice. Tumor uptake was assessed in mice bearing EL4-hCD20 and EL4-WT subcutaneous xenografts. With optimized method, high radiolabeling yields were obtained (95.9 ± 3.5%. 99mTc-IgG-SH was stable in phosphate-buffered saline (4°C and 25°C and in serum (37°C, even if important sensitivity to transchelation was observed. IgG was not degraded by derivatization and radiolabeling, as shown by Western blot and autoradiography results. 99mTc-anti-CD20 IgG-SH immunoaffinity was estimated with Kd = 35 nM by both methods. In vivo biodistribution studies for 48h showed significant accumulation of radioactivity in plasma, liver, spleen, lungs and kidneys. Planar scintigraphy of mice bearing tumors showed a significant uptake of 99mTc-anti-CD20 IgG-SH in CD20+ tumor versus CD20- tumor. Radiolabeling of derivatized IgG with 99mTc-tricarbonyl was effective, stable and required few antibody amounts. This attractive radiolabeling method is "antibody safe

Evaluation of New and Proposed Organic Aerosol Sources and Mechanisms using the Aerosol Modeling Testbed. MILAGRO, CARES, CalNex, BEACHON, and GVAX

Energy Technology Data Exchange (ETDEWEB)

Hodzic, Alma [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Jimenez, Jose L. [Univ. of Colorado, Boulder, CO (United States)

2015-04-09

This work investigated the formation and evolution of organic aerosols (OA) arising from anthropogenic and biogenic sources in a framework that combined state-of-the-science process and regional modeling, and their evaluation against advanced and emerging field measurements. Although OA are the dominant constituents of submicron particles, our understanding of their atmospheric lifecycle is limited, and current models fail to describe the observed amounts and properties of chemically formed secondary organic aerosols (SOA), leaving large uncertainties on the effects of SOA on climate. Our work has provided novel modeling constraints on sources, formation, aging and removal of SOA by investigating in particular (i) the contribution of trash burning emissions to OA levels in a megacity, (ii) the contribution of glyoxal to SOA formation in aqueous particles in California during CARES/CalNex and over the continental U.S., (iii) SOA formation and regional growth over a pine forest in Colorado and its sensitivity to anthropogenic NOx levels during BEACHON, and the sensitivity of SOA to (iv) the sunlight exposure during its atmospheric lifetime, and to (v) changes in solubility and removal of organic vapors in the urban plume (MILAGRO, Mexico City), and over the continental U.S.. We have also developed a parameterization of water solubility for condensable organic gases produced from major anthropogenic and biogenic precursors based on explicit chemical modeling, and made it available to the wider community. This work used for the first time constraints from the explicit model GECKO-A to improve SOA representation in 3D regional models such as WRF-Chem.

Aircraft-Based measurement of the physico-chemical evolution of atmospheric aerosols in the air pollution plume over a megacity and a remote area

Science.gov (United States)

Park, J. S.; Lee, T.; Park, T.; Lee, J. B.; Lim, Y. J.; Ahn, J.; Kim, J.; Park, S.; Collett, J. L., Jr.

2017-12-01

Aerosols influence climate change directly (scattering and absorption) and indirectly (cloud condensation nuclei), also adverse health effects. The Korean peninsula is a great place to study different sources of the aerosols: urban, rural and marine. In addition, Seoul is one of the large metropolitan areas in the world and has a variety of sources because half of the Korean population lives in Seoul, which comprises only 12% of the country's area. To understand the physico-chemical evolution of atmospheric aerosols in the air pollution plume over a megacity and a remote area, an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed on an airborne platform (NASA DC-8 and Beechcraft King Air) in June, 2015 and May-June, 2016 during MAPS-Seoul and KORUS-AQ campaigns, respectively, in Korea. The HR-ToF-AMS is capable of measuring non-refractory size resolved chemical composition of submicron particle (NR-PM1). NR-PM1 includes mass concentration of organics, nitrate, sulfate, and ammonium with 10 seconds time resolution. Organics was dominated species in aerosol during all of flights. Organics and nitrate were dominant around energy industrial complex near by Taean, South Korea. The presentation will provide an overview of the composition of NR-PM1 measured in air pollution plumes, and deliver detail information about width, depth and spatial distribution of the pollutant in the air pollution plumes. The results of this study will provide high temporal and spatial resolved details on the air pollution plumes, which are valuable input parameters of aerosol properties for the current air quality models.

Unipolar charging of nanoparticles by the Surface-discharge Microplasma Aerosol Charger (SMAC)

International Nuclear Information System (INIS)

Kwon, Soon-Bark; Sakurai, Hiromu; Seto, Takafumi

2007-01-01

In this paper, we report the development of a novel unipolar charger for nanoparticles, a system that achieves low particle loss and high charging efficiency without the use of sheath air. The efficient unipolar charging of the system is realized mainly by the surface-discharge microplasma unit, a device previously applied with good success to the neutralization or charging of submicron particles [Kwon et al., 2005, Aerosol Sci. Technol., 39, 987-1001; 2006, J. Aerosol Sci., 37, 483-499]. The unipolar charger generates unipolar ions using the surface discharge of a single electrode with a DC pulse supply. This marks an advance from our previous method of generating bipolar ions with the use of dual electrodes in earlier studies. We evaluated the efficiency of the penetration (or loss) and charging of nanoparticles in the size range of 3-15 nm, then compared the charging efficiencies measured with those predicted by diffusion charging theory. More than 90% of inlet nanoparticles penetrated the charger (less than 10% of the particle were lost) without the use of sheath air. Other chargers have only realized this high penetration efficiency by relying on sheath air flow. Moreover, the measured charging efficiencies agreed well with those predicted by diffusion charging theory and were somewhat higher and more size-dependent than the charging efficiencies of other nanoparticle chargers

Heterogeneous reactions and aerosol formation in flue gas cleaning by electron beam

International Nuclear Information System (INIS)

Baumann, W.; Jordan, S.; Leichsenring, C.H.; Maetzing, H.; Paur, H.R.; Schikarski, W.

1990-08-01

The electron beam dry scrubbing process is a simultaneous method for the removal of SO 2 and NO x from flue gas. By electron irradiation radicals (OH, O 2 H, O) are formed from the main flue gas components which oxidize NO x and SO 2 into the acids HNO 3 and H 2 SO 4 . These are then neutralized by the injection of NH 3 . A submicron aerosol consisting of ammonium salts is formed which is filtered from the offgas. The main pathways of the gas phase chemistry and product formation have been elucidated by experimental and theoretical studies. Back reactions which occur in the gas and the particle phase limit the energy efficiency of the process. By recirculation of irradiated gas into the reaction vessel (multiple irradiation) a significant improvement of removal yields was obtained. This enhancement of the energy efficiency requires the removal of products between the irradiation steps. Studies show that the material balance is complete. Deficits in the N and S balance of the process are due to the additional formation of molecular nitrogen and the deposition of ammonium sulfate in the ducts. Aerosol formation participates only with 30% in the material balance. The remaining 70% of the product are formed by surface reactions in the filter cake (40%) and in the ducts (30%). (orig.) With 38 figs., 29 tabs [de

(99m)Tc-aprotinin - optimisation and validation of radiolabelling kits for routine preparation for diagnostic imaging of amyloidosis

DEFF Research Database (Denmark)

Denholt, Charlotte; Gillings, Nic

2016-01-01

Technetium-99m aprotinin was prepared from an optimised radiolabelling kit formulation containing aprotinin, alkaline buffer and stannous chloride (reducing agent) and radiolabelled using (99m) Tc-pertechnetate. The labelling was achieved within 25 min, with radiochemical purities of >98%....

Submicron and nano formulations of titanium dioxide and zinc oxide stimulate unique cellular toxicological responses in the green microalga Chlamydomonas reinhardtii

Energy Technology Data Exchange (ETDEWEB)

Gunawan, Cindy, E-mail: c.gunawan@unsw.edu.au [ARC Centre of Excellence for Functional Nanomaterials, School of Chemical Engineering, The University of New South Wales, Sydney, NSW (Australia); Sirimanoonphan, Aunchisa [ARC Centre of Excellence for Functional Nanomaterials, School of Chemical Engineering, The University of New South Wales, Sydney, NSW (Australia); Teoh, Wey Yang [Clean Energy and Nanotechnology (CLEAN) Laboratory, School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region (Hong Kong); Marquis, Christopher P., E-mail: c.marquis@unsw.edu.au [School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW (Australia); Amal, Rose [ARC Centre of Excellence for Functional Nanomaterials, School of Chemical Engineering, The University of New South Wales, Sydney, NSW (Australia)

2013-09-15

Highlights: • Uptake of TiO{sub 2} solids by C. reinhardtii generates ROS as an early stress response. • Submicron and nanoTiO{sub 2} exhibit benign effect on cell proliferation. • Uptake of ZnO solids and leached zinc by C. reinhardtii inhibit the alga growth. • No cellular oxidative stress is detected with submicron and nano ZnO exposure. • The toxicity of particles is not necessarily mediated by cellular oxidative stress. -- Abstract: The work investigates the eco-cytoxicity of submicron and nano TiO{sub 2} and ZnO, arising from the unique interactions of freshwater microalga Chlamydomonas reinhardtii to soluble and undissolved components of the metal oxides. In a freshwater medium, submicron and nano TiO{sub 2} exist as suspended aggregates with no-observable leaching. Submicron and nano ZnO undergo comparable concentration-dependent fractional leaching, and exist as dissolved zinc and aggregates of undissolved ZnO. Cellular internalisation of solid TiO{sub 2} stimulates cellular ROS generation as an early stress response. The cellular redox imbalance was observed for both submicron and nano TiO{sub 2} exposure, despite exhibiting benign effects on the alga proliferation (8-day EC50 > 100 mg TiO{sub 2}/L). Parallel exposure of C. reinhardtii to submicron and nano ZnO saw cellular uptake of both the leached zinc and solid ZnO and resulting in inhibition of the alga growth (8-day EC50 ≥ 0.01 mg ZnO/L). Despite the sensitivity, no zinc-induced cellular ROS generation was detected, even at 100 mg ZnO/L exposure. Taken together, the observations confront the generally accepted paradigm of cellular oxidative stress-mediated cytotoxicity of particles. The knowledge of speciation of particles and the corresponding stimulation of unique cellular responses and cytotoxicity is vital for assessment of the environmental implications of these materials.

Submicron and nano formulations of titanium dioxide and zinc oxide stimulate unique cellular toxicological responses in the green microalga Chlamydomonas reinhardtii

International Nuclear Information System (INIS)

Gunawan, Cindy; Sirimanoonphan, Aunchisa; Teoh, Wey Yang; Marquis, Christopher P.; Amal, Rose

2013-01-01

Highlights: • Uptake of TiO 2 solids by C. reinhardtii generates ROS as an early stress response. • Submicron and nanoTiO 2 exhibit benign effect on cell proliferation. • Uptake of ZnO solids and leached zinc by C. reinhardtii inhibit the alga growth. • No cellular oxidative stress is detected with submicron and nano ZnO exposure. • The toxicity of particles is not necessarily mediated by cellular oxidative stress. -- Abstract: The work investigates the eco-cytoxicity of submicron and nano TiO 2 and ZnO, arising from the unique interactions of freshwater microalga Chlamydomonas reinhardtii to soluble and undissolved components of the metal oxides. In a freshwater medium, submicron and nano TiO 2 exist as suspended aggregates with no-observable leaching. Submicron and nano ZnO undergo comparable concentration-dependent fractional leaching, and exist as dissolved zinc and aggregates of undissolved ZnO. Cellular internalisation of solid TiO 2 stimulates cellular ROS generation as an early stress response. The cellular redox imbalance was observed for both submicron and nano TiO 2 exposure, despite exhibiting benign effects on the alga proliferation (8-day EC50 > 100 mg TiO 2 /L). Parallel exposure of C. reinhardtii to submicron and nano ZnO saw cellular uptake of both the leached zinc and solid ZnO and resulting in inhibition of the alga growth (8-day EC50 ≥ 0.01 mg ZnO/L). Despite the sensitivity, no zinc-induced cellular ROS generation was detected, even at 100 mg ZnO/L exposure. Taken together, the observations confront the generally accepted paradigm of cellular oxidative stress-mediated cytotoxicity of particles. The knowledge of speciation of particles and the corresponding stimulation of unique cellular responses and cytotoxicity is vital for assessment of the environmental implications of these materials

Light-Absorbing Aerosol during NASA GRIP: Overview of Observations in the Free Troposphere and Associated with Tropical Storm Systems

Science.gov (United States)

Ziemba, L. D.; Beyersdorf, A. J.; Chen, G.; Corr, C. A.; Craig, L.; Dhaniyala, S.; Dibb, J. E.; Hudgins, C. H.; Ismail, S.; Latham, T.; Nenes, A.; Thornhill, K. L.; Winstead, E.; Anderson, B. E.

2010-12-01

Aerosols play a significant role in regulating Earth’s climate. Absorbing aerosols typically constitute a small fraction of ambient particle mass but can contribute significantly to direct and indirect climate forcing depending on size, mixing state, concentration, chemical composition, and vertical and spatial distribution. Aerosols may also significantly affect tropical storm/hurricane dynamics through direct light absorption and activation as cloud nuclei. An extensive suite of instrumentation measuring aerosol chemical, physical, and optical properties was deployed aboard the NASA DC-8 to characterize aerosol during the NASA GRIP (Genesis and Rapid Intensification Processes; August-September 2010) mission. The majority of flight time was spent at high altitude (greater than 9 km) and thus much of the sampling was done in the free troposphere, including extensive sampling in the vicinity of tropical storm systems and more diffuse cirrus clouds. With operations based in Fort Lauderdale, FL and St. Croix, U.S. Virgin Islands, a large geographic region was sampled including much of the Gulf of Mexico and tropical Atlantic Ocean. Observations are reported for light-absorbing carbon aerosol (mainly black carbon, BC) primarily using a single particle soot photometer (SP2). The SP2 employs single-particle laser-induced incandescence to provide a mass-specific measurement not subject to scattering interference that is optimal for the low concentration environments like those encountered during GRIP. BC mass concentrations, 100-500 nm size distributions, and mixing state (i.e. coating thickness of scattering material) are presented. Total and sub-micron aerosol absorption coefficients (principally from BC and dust aerosol) are reported using a particle soot absorption photometer (PSAP) along with comparisons with calculated absorption coefficients derived from SP2 observations in various conditions. In addition, dust aerosol is specifically identified using optical and

Potential of 57Ni/57Co generator system for radiolabelling proteins for imaging

International Nuclear Information System (INIS)

Du, T.; Smith, S.V.; Baker, T.

1998-01-01

Full text: There is increasing interest in the use of inert metal complexes for radiolabelling proteins. The present study involves an investigation into the use to the parent/daughter system 57 Ni/ 57 Co for PET and SPECT imaging. In order to assess the potential of the system for such applications it is important to examine whether the ligand chosen complexes with both 57 Ni and 57 Co. A selection of ligands with varying number of donor groups and open-chain and macrocyclic ligands were chosen; ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), 1,4,8,11 - tetraazocyclotetradecane-1 4,8,11-tetraacetic acid (TETA) and diaminohydroxyaryl - diethylenetriaminepentaacetic acid, (DAHA-EDTA). Complexation behaviour over a range of pH and temperatures was investigated. Results show that the ligands have strong complexation for 57 Ni however once 57 Ni decayed to 57 Co evidence ol chemical instability was noted. The DAHA-EDTA ligand (developed in house) was observed to be the most stable under conditions studied. lt was selected for use in radiolabelling B72.3 antibody and preliminary radiolabelling conditions were established

The Impact of Nonlocal Ammonia on Submicron Particulate Matter and Visibility Degradation in Urban Shanghai

Directory of Open Access Journals (Sweden)

Roeland Cornelis Jansen

2014-01-01

Full Text Available To study the role of submicron particulate matter on visibility degradation in Shanghai, mass concentrations of PM1, secondary inorganic aerosol (SIA in PM1, and SIA precursor gasses were on-line monitored during a 4-week intensive campaign in December 2012. During the campaign, 8 haze periods were identified when on average PM1 mass increased to 62.1 ± 25.6 μg/m3 compared to 30.7 ± 17.1 μg/m3 during clear weather periods. The sum of SIA in PM1 increased in mass concentration during the haze from 14.9 ± 7.4 μg/m3 during clear periods to 29.7 ± 10.7 μg/m3 during the haze periods. Correlation coefficients (R2 of the visibility as function of mass concentrations of SIA species in PM1 show negative exponential relations implying the importance of the SIA species in visibility reduction. The important role of ammonia in SIA formation is recognized and demonstrated. Generally, ammonium neutralizes sulfate and nitrate and the molar equivalent ratio of ammonium versus the sum of sulfate and nitrate increases during the haze episodes. Air mass backward trajectories introducing the haze periods show the impact of nonlocal ammonia on visibility degradation in Shanghai.

Sources and atmospheric processing of winter aerosols in Seoul, Korea: insights from real-time measurements using a high-resolution aerosol mass spectrometer

Science.gov (United States)

Kim, Hwajin; Zhang, Qi; Bae, Gwi-Nam; Kim, Jin Young; Bok Lee, Seung

2017-02-01

Highly time-resolved chemical characterization of nonrefractory submicrometer particulate matter (NR-PM1) was conducted in Seoul, the capital and largest metropolis of Korea, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The measurements were performed during winter, when elevated particulate matter (PM) pollution events are often observed. This is the first time that detailed real-time aerosol measurement results have been reported from Seoul, Korea, and they reveal valuable insights into the sources and atmospheric processes that contribute to PM pollution in this region. The average concentration of submicron aerosol (PM1 = NR-PM1+ black carbon (BC)) was 27.5 µg m-3, and the total mass was dominated by organics (44 %), followed by nitrate (24 %) and sulfate (10 %). The average atomic ratios of oxygen to carbon (O / C), hydrogen to carbon (H / C), and nitrogen to carbon (N / C) of organic aerosols (OA) were 0.37, 1.79, and 0.018, respectively, which result in an average organic mass-to-carbon (OM / OC) ratio of 1.67. The concentrations (2.6-90.7 µg m-3) and composition of PM1 varied dynamically during the measurement period due to the influences of different meteorological conditions, emission sources, and air mass origins. Five distinct sources of OA were identified via positive matrix factorization (PMF) analysis of the HR-ToF-AMS data: vehicle emissions represented by a hydrocarbon-like OA factor (HOA, O / C = 0.06), cooking activities represented by a cooking OA factor (COA, O / C = 0.14), wood combustion represented by a biomass burning OA factor (BBOA, O / C = 0.34), and secondary organic aerosol (SOA) represented by a semivolatile oxygenated OA factor (SV-OOA, O / C = 0.56) and a low-volatility oxygenated OA factor (LV-OOA, O / C = 0.68). On average, primary OA (POA = HOA + COA + BBOA) accounted for 59 % the OA mass, whereas SV-OOA and LV-OOA contributed 15 and 26 %, respectively. Our results indicate that air

Kinetics of Sub-Micron Grain Size Refinement in 9310 Steel

Science.gov (United States)

Kozmel, Thomas; Chen, Edward Y.; Chen, Charlie C.; Tin, Sammy

2014-05-01

Recent efforts have focused on the development of novel manufacturing processes capable of producing microstructures dominated by sub-micron grains. For structural applications, grain refinement has been shown to enhance mechanical properties such as strength, fatigue resistance, and fracture toughness. Through control of the thermo-mechanical processing parameters, dynamic recrystallization mechanisms were used to produce microstructures consisting of sub-micron grains in 9310 steel. Starting with initial bainitic grain sizes of 40 to 50 μm, various levels of grain refinement were observed following hot deformation of 9310 steel samples at temperatures and strain rates ranging from 755 K to 922 K (482 °C and 649 °C) and 1 to 0.001/s, respectively. The resulting deformation microstructures were characterized using scanning electron microscopy and electron backscatter diffraction techniques to quantify the extent of carbide coarsening and grain refinement occurring during deformation. Microstructural models based on the Zener-Holloman parameter were developed and modified to include the effect of the ferrite/carbide interactions within the system. These models were shown to effectively correlate microstructural attributes to the thermal mechanical processing parameters.

Characterization of aerosols produced by laser-matter interaction during paint-stripping experiments by laser

International Nuclear Information System (INIS)

Dewalle, P.

2009-01-01

Laser ablation is one of the physical processes that are being considered for paint stripping in possibly contaminated areas, especially for decommissioning and dismantling of nuclear facilities. In this regard, the knowledge of 'ablation products', consisting of particles and gases, is an important issue.The numeric and weight concentration of particles, their size distribution, their morphology and their density have been determined for laser ablation of two wall paints. The main gas species have also been identified. The aerosol is composed of nano-particles, of which the number is predominant, and sub-micron particles. Their morphologies and their chemical composition are very distinct: carbon aggregates have been identified, as well as spherical particles of titanium dioxide. These results show that nano-scale aggregates come from the vaporization of the paint polymer, whereas sub-micron particles are due to mechanical ejection of titanium dioxide particles. The expansion of the plume resulting from laser-paint interaction has been monitored by means of three optical techniques: light extinction, scattering and emission. The frames show the propagation of a shock wave followed by the ejection of matter with a specific 'mushroom' shape. Measurements based on these results show that the peripheral part of the plume contains the primary particles of carbon aggregates; it is the warmest area, which reaches a few thousands Kelvin degrees. Its central part is composed of titanium dioxide spherical particles. (author) [fr

Characterizing the Sources and Processing of Submicron Aerosols at a Coastal Site near Houston, TX, with a Specific Focus on the Impact of Regional Shipping Emissions

Science.gov (United States)

Schulze, B.; Wallace, H. W., IV; Bui, A.; Flynn, J. H., III; Erickson, M. H.; Griffin, R. J.

2017-12-01

The Texas Gulf Coast region historically has been influenced heavily by regional shipping emissions. However, the effects of the recent establishment of the North American Emissions Control Area (ECA) on aerosol properties in this region are presently unknown. In order to understand better the current sources and processing mechanisms influencing coastal aerosol near Houston, a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed for three weeks at a coastal location during May-June 2016. Total mass loadings of organic and inorganic non-refractory aerosol components during onshore flow periods were similar to those published before establishment of the regulations. Using estimated methanesulfonic acid (MSA) mass loadings and published biogenic MSA:non-sea-salt-sulfate (nss-SO4) ratios, we determined that over 70% of nss-SO4 over the Gulf was from anthropogenic sources, predominantly shipping emissions. Mass spectral analysis indicated that for periods with similar backward-trajectory-averaged meteorological conditions, air masses influenced by shipping emissions have an increased mass fraction of ions related to carboxylic acids and a significantly larger oxygen-to-carbon (O:C) ratio than air masses that stay within the ECA boundary, suggesting that shipping emissions impact marine organic aerosol (OA) oxidation state. Amine fragment mass loadings were positively correlated with anthropogenic nss-SO4 during onshore flow, implying anthropogenic-biogenic interaction in marine OA production. Five OA factors were resolved by positive matrix factorization, corresponding to a hydrocarbon-like OA, a semi-volatile OA, and three different oxygenated organic aerosols ranked by their O:C ratio (OOA-1, OOA-2, and OOA-3). OOA-1 constituted the majority of OA mass during a period likely influenced by aqueous-phase processing and may be linked to local glyoxal/methylglyoxal-related sources. OOA-2 was produced within the Houston urban region and was

A radiolabeled antiglobulin assay to identify human cervical mucus immunoglobulin (Ig) A and IgG antisperm antibodies

International Nuclear Information System (INIS)

Haas, G.G. Jr.; D'Cruz, O.J.

1989-01-01

Antisperm immunoglobulin (Ig) A and IgG antibodies in human cervical mucus (CM) were identified by a radiolabeled antiglobulin assay. Cervical mucus samples from fertile and infertile women were exposed to a 1:3,200 dilution of 2-mercaptoethanol (2-ME), and 5 micrograms of the solubilized CM protein were assayed for the presence of IgA and IgG antisperm and anti-Candida activity by the radiolabeled antiglobulin assay. Purified human secretory IgA and IgG exposed to 2-ME retained the molecular integrity and functional activity of the untreated antibody molecules. CM aliquots collected after high-performance liquid chromatography (HPLC) fractionation were assessed for antisperm antibody activity; antisperm antibody activity was retained in the appropriate IgA or IgG CM fractions. The incidence of CM antisperm antibodies was minimally affected when the radiolabeled antiglobulin assay was performed with a motile sperm population. Approximately 70% of the CM IgA antisperm antibodies were of the IgA1 subclass; CM IgG was primarily of the IgG4 subclass. When Candida antigen was substituted for sperm in the radiolabeled antiglobulin assay, the CM antisperm antibodies were found to be exclusively sperm-specific. These data indicate that the radiolabeled antiglobulin assay using 2-ME to extract CM antibodies is a specific method for the assay of antisperm antibodies in CM

Development of radiolabeled mannose-dextran conjugates for sentinel lymph node detection

International Nuclear Information System (INIS)

Fernandez Nunez, Eutimio Gustavo

2011-01-01

Early diagnosis of tumors and metastasis is the current cornerstone in public health policies directed towards the fights against cancer. In breast cancer and melanoma, the sentinel lymph node biopsy has been widely used for diagnoses of metastasis. The minor impact in patient of this technique compared with total nodes dissection and the accurate definition of therapeutic strategies have powered its spreading. The aim of this work was the development of radiolabeled dextran-mannose conjugates for diagnosis using the stable technetium core [ 99m Tc(CO)3] + . Cysteine, a trident ligand, was attached to the conjugates backbone, as a chelate for 99m Tc labeling. Radiolabeling conditions established for all products considered in this study showed high radiochemical purities (> 90%) and specific activities (>59,9 MBq/nmol) as well and high stability obtained through in vitro tests. The lymphatic node uptake increased significantly (4-folds) when mannose units were added to the conjugates compared with those without this monosaccharide. The radiolabeled cysteine-mannose-dextran conjugate with 30 kDa ( 99m Tc - DCM2) showed the best performance at different injected activities among the studied tracers. Concentrations of this radio complex higher than 1 M demonstrated an improvement of lymph node uptakes. Comparisons of 99m Tc - DCM2 performance with commercial radiopharmaceuticals in Brazil market for lymph node detection showed its upper profile. (author)

Field characterization of the PM2.5 Aerosol Chemical Speciation Monitor: insights into the composition, sources, and processes of fine particles in eastern China

Directory of Open Access Journals (Sweden)

Y. Zhang

2017-12-01

Full Text Available A PM2.5-capable aerosol chemical speciation monitor (Q-ACSM was deployed in urban Nanjing, China, for the first time to measure in situ non-refractory fine particle (NR-PM2.5 composition from 20 October to 19 November 2015, along with parallel measurements of submicron aerosol (PM1 species by a standard Q-ACSM. Our results show that the NR-PM2.5 species (organics, sulfate, nitrate, and ammonium measured by the PM2.5-Q-ACSM are highly correlated (r2 > 0.9 with those measured by a Sunset Lab OC  /  EC analyzer and a Monitor for AeRosols and GAses (MARGA. The comparisons between the two Q-ACSMs illustrated similar temporal variations in all NR species between PM1 and PM2.5, yet substantial mass fractions of aerosol species were observed in the size range of 1–2.5 µm. On average, NR-PM1−2.5 contributed 53 % of the total NR-PM2.5, with sulfate and secondary organic aerosols (SOAs being the two largest contributors (26 and 27 %, respectively. Positive matrix factorization of organic aerosol showed similar temporal variations in both primary and secondary OAs between PM1 and PM2.5, although the mass spectra were slightly different due to more thermal decomposition on the capture vaporizer of the PM2.5-Q-ACSM. We observed an enhancement of SOA under high relative humidity conditions, which is associated with simultaneous increases in aerosol pH, gas-phase species (NO2, SO2, and NH3 concentrations and aerosol water content driven by secondary inorganic aerosols. These results likely indicate an enhanced reactive uptake of SOA precursors upon aqueous particles. Therefore, reducing anthropogenic NOx, SO2, and NH3 emissions might not only reduce secondary inorganic aerosols but also the SOA burden during haze episodes in China.

Aerosol characterization over the southeastern United States using high resolution aerosol mass spectrometry: spatial and seasonal variation of aerosol composition, sources, and organic nitrates

Science.gov (United States)

Xu, L.; Suresh, S.; Guo, H.; Weber, R. J.; Ng, N. L.

2015-04-01

We deployed a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aerosol Chemical Speciation Monitor (ACSM) to characterize the chemical composition of submicron non-refractory particles (NR-PM1) in the southeastern US. Measurements were performed in both rural and urban sites in the greater Atlanta area, GA and Centreville, AL for approximately one year, as part of Southeastern Center of Air Pollution and Epidemiology study (SCAPE) and Southern Oxidant and Aerosol Study (SOAS). Organic aerosol (OA) accounts for more than half of NR1 mass concentration regardless of sampling sites and seasons. Positive matrix factorization (PMF) analysis of HR-ToF-AMS measurements identified various OA sources, depending on location and season. Hydrocarbon-like OA (HOA) and cooking OA (COA) have important but not dominant contributions to total OA in urban sites. Biomass burning OA (BBOA) concentration shows a distinct seasonal variation with a larger enhancement in winter than summer. We find a good correlation between BBOA and brown carbon, indicating biomass burning is an important source for brown carbon, although an additional, unidentified brown carbon source is likely present at the rural Yorkville site. Isoprene-derived OA (Isoprene-OA) is only deconvolved in warmer months and contributes 18-36% of total OA. The presence of Isoprene-OA factor in urban sites is more likely from local production in the presence of NOx than transport from rural sites. More-oxidized and less-oxidized oxygenated organic aerosol (MO-OOA and LO-OOA, respectively) are dominant fractions (47-79%) of OA in all sites. MO-OOA correlates well with ozone in summer, but not in winter, indicating MO-OOA sources may vary with seasons. LO-OOA, which reaches a daily maximum at night, correlates better with estimated nitrate functionality from organic nitrates than total nitrates. Based on the HR-ToF-AMS measurements, we estimate that the nitrate functionality from organic nitrates

Method for radio imaging the myocardium of mammals using radio-labelled lipophil cations

International Nuclear Information System (INIS)

1984-01-01

The invention relates to a method for the radio imaging of myocardia of mammals by concentrating a radiolabelled cation in myocardial tissue and by producing a radiograph using imaging techniques. According to the invention, it is found that a group of substances shows a preference to myocardial tissues upon intravenous injection in mammals. The characteristic of the invention is that radiolabelled quaternary ammonium, quaternary phosphorous or quaternary arsenic compounds with at least two aryl groups are intravenously injected. These substances provide a sufficiently high radioactivity giving an approved diagnostic image of the myocardium. (G.J.P.)

Source identification and airborne chemical characterisation of aerosol pollution from long-range transport over Greenland during POLARCAT summer campaign 2008

Directory of Open Access Journals (Sweden)

J. Schmale

2011-10-01

Full Text Available We deployed an aerosol mass spectrometer during the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport summer campaign in Greenland in June/July 2008 on the research aircraft ATR-42. Online size resolved chemical composition data of submicron aerosol were collected up to 7.6 km altitude in the region 60 to 71° N and 40 to 60° W. Biomass burning (BB and fossil fuel combustion (FF plumes originating from North America, Asia, Siberia and Europe were sampled. Transport pathways of detected plumes included advection below 700 hPa, air mass uplifting in warm conveyor belts, and high altitude transport in the upper troposphere. By means of the Lagrangian particle dispersion model FLEXPART, trace gas analysis of O₃ and CO, particle size distributions and aerosol chemical composition 48 pollution events were identified and classified into five chemically distinct categories. Aerosol from North American BB consisted of 22% particulate sulphate, while with increasing anthropogenic and Asian influence aerosol in Asian FF dominated plumes was composed of up to 37% sulphate category mean value. Overall, it was found that the organic matter fraction was larger (85% in pollution plumes than for background conditions (71%. Despite different source regions and emission types the particle oxygen to carbon ratio of all plume classes was around 1 indicating low-volatility highly oxygenated aerosol. The volume size distribution of out-of-plume aerosol showed markedly smaller modes than all other distributions with two Aitken mode diameters of 24 and 43 nm and a geometric standard deviation σ_g of 1.12 and 1.22, respectively, while another very broad mode was found at 490 nm (σ_g = 2.35. Nearly pure BB particles from North America exhibited an Aitken mode at 66 nm (σ_g = 1.46 and an accumulation mode diameter of 392 nm (σ_g = 1

Approaches in the design of 99mTc based peptide radiolabelling for tumour targeting

International Nuclear Information System (INIS)

Yokoyama, A.; Horiuchi, K.; Arano, Y.

2001-01-01

One of the major drawbacks in diagnostic and/or therapeutic uses of peptides radiolabelled with radiometals via bifunctional chelating agents (BCA) is their accumulation in excretory organs such as liver or kidney. Thus, the aim of the project is centred in the search for chemical and radiochemical approaches to reduce radioactivity accumulated in excretory organs while preserving the in vivo receptor binding affinity of the peptide. During the first stage a suitable procedure using the F-moc-chemistry (solid phase) was developed and synthesis of DTPA-D-Phen1-Octreotide and DTPA-L-Phen1-Octreotide was carried out. During the synthesis, the need to improve the yield demanded the synthesis of a DTPA derivative holding only one reactive carboxylic group to avoid side intermolecular reaction. The availability of both isomeric conjugated octreotide led to their radiolabelling with 111 In. Their metabolic studies in animals indicated that the degradation rate of the peptide containing the natural aminoacid, 111 In DTPA-L-Phen1-Octreotide, was slightly higher than the corresponding D-aminoacid derivative, as expected. Stability of the peptide during radiolabelling with 99m Tc was then studied, requiring the use of variable agents such as ascorbic acid, dithionite and stannous ion. The selected peptide, RC-160, was provided by the IAEA and, as reference compounds, corresponding iodinated and radioiodinated peptides were synthesized. Demonstration of the stability of the peptide was carried out using disodium 2-nitro-5-thiosulfobenzoate (NTBS) and the lack of Bunte salt formation served as an indication of the stability of the disulfide bond under various mild conditions required for the future radiolabelling with 99m Tc. The knowledge gained served in moving to the next stage of 99m Tc radiolabelling using HYNIC as the BCA and tricine as co-ligands. The biodistribution studies demonstrated great accumulation on excretory organs. This led us to look for a model protein

Submicron, soft x-ray fluorescence imaging

International Nuclear Information System (INIS)

La Fontaine, B.; MacDowell, A.A.; Tan, Z.; White, D.L.; Taylor, G.N.; Wood, O.R. II; Bjorkholm, J.E.; Tennant, D.M.; Hulbert, S.L.

1995-01-01

Submicron fluorescence imaging of soft x-ray aerial images, using a high resolution fluorescent crystal is reported. Features as small as 0.1 μm were observed using a commercially available single-crystal phosphor, STI-F10G (Star Tech Instruments Inc. P. O. Box 2536, Danbury, CT 06813-2536), excited with 139 A light. Its quantum efficiency was estimated to be 5--10 times that of sodium salicylate and to be constant over a broad spectral range from 30 to 400 A. A comparison with a terbium-activated yttrium orthosilicate fluorescent crystal is also presented. Several applications, such as the characterization of the aerial images produced by deep ultraviolet or extreme ultraviolet lithographic exposure tools, are envisaged

Lift-off process for deep-submicron-size junctions using supercritical CO2

International Nuclear Information System (INIS)

Fukushima, A.; Kubota, H.; Yuasa, S.; Takahachi, T.; Kadoriku, S.; Miyake, K.

2007-01-01

Deep-submicron-size (∼100-nm-size) junctions are a key element to investigate spin-torque transfer phenomena such as current induced magnetization reversal or the spin-torque diode effect. In the fabrication of submicron-size junctions using an etching method, the lift-off process after the etching process tends to be difficult as the size of junctions shrinks. In this study, we present a new lift-off process using supercritical CO 2 . In this process, the samples were immersed in solvent (mixture of N-Methyl-2-pyrrolidone and isopropanol), and pressurized by CO 2 gas. The CO 2 gas then went into supercritical phase and the solvent was removed by a continuous flow of CO 2 . We obtained considerable yield rate (success ratio in lift-off process) of more than 50% for the samples down to 100-nm-size junctions

Fine aerosol bulk composition measured on WP-3D research aircraft in vicinity of the Northeastern United States – results from NEAQS

Directory of Open Access Journals (Sweden)

C. Warneke

2007-06-01

Full Text Available During the New England Air Quality Study (NEAQS in the summer of 2004, airborne measurements were made of the major inorganic ions and the water-soluble organic carbon (WSOC of the submicron (PM1.0 aerosol. These and ancillary data are used to describe the overall aerosol chemical characteristics encountered during the study. Fine particle mass was estimated from particle volume and a calculated density based on measured particle composition. Fine particle organic matter (OM was estimated from WSOC and a mass balance analysis. The aerosol over the northeastern United States (U.S. and Canada was predominantly sulfate and associated ammonium, and organic components, although in unique plumes additional ionic components were also periodically above detection limits. In power generation regions, and especially in the Ohio River Valley region, the aerosol tended to be predominantly sulfate (~60% μg μg−1 and apparently acidic, based on an excess of measured anions compared to cations. In all other regions where sulfate concentrations were lower and a smaller fraction of overall mass, the cations and anions were balanced suggesting a more neutral aerosol. In contrast, the WSOC and estimated OM were more spatially uniform and the fraction of OM relative to PM mass was largely influenced by sources of sulfate. The study median OM mass fraction was 40%. Throughout the study region, sulfate and organic aerosol mass were highest near the surface and decreased rapidly with increasing altitude. The relative fraction of organic mass to sulfate was similar throughout all altitudes within the boundary layer (altitude less than 2.5 km, but was significantly higher at altitude layers in the free troposphere (above 2.5 km. A number of distinct biomass burning plumes from fires in Alaska and the Yukon were periodically intercepted, mostly at altitudes between 3 and 4 km. These plumes were associated with highest aerosol concentrations of the study and were

Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS through laboratory studies of inorganic species

Directory of Open Access Journals (Sweden)

W. Hu

2017-08-01

Full Text Available Aerosol mass spectrometers (AMSs and Aerosol Chemical Speciation Monitors (ACSMs commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE to correct for the loss of particles due to bounce. A new capture vapourizer (CV has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in the laboratory. Four standard species, NH4NO3, NaNO3, (NH42SO4 and NH4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature (Tv ∼ 200–800 °C on the detected fragments, CE and size distributions are investigated. A Tv of 500–550 °C for the CV is recommended. In the CV, CE was identical (around unity for more volatile species (e.g. NH4NO3 and comparable to or higher than the SV for less-volatile species (e.g. (NH42SO4, demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO3 and SO4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO2(g from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH4NO3 and comparable to the SV for NaNO3. . We observe an extremely consistent fragmentation for ammonium compared to very

Fabrication of submicron structures in nanoparticle/polymer composite by holographic lithography and reactive ion etching

Science.gov (United States)

Zhang, A. Ping; He, Sailing; Kim, Kyoung Tae; Yoon, Yong-Kyu; Burzynski, Ryszard; Samoc, Marek; Prasad, Paras N.

2008-11-01

We report on the fabrication of nanoparticle/polymer submicron structures by combining holographic lithography and reactive ion etching. Silica nanoparticles are uniformly dispersed in a (SU8) polymer matrix at a high concentration, and in situ polymerization (cross-linking) is used to form a nanoparticle/polymer composite. Another photosensitive SU8 layer cast upon the nanoparticle/SU8 composite layer is structured through holographic lithography, whose pattern is finally transferred to the nanoparticle/SU8 layer by the reactive ion etching process. Honeycomb structures in a submicron scale are experimentally realized in the nanoparticle/SU8 composite.

Reactivity comparison of biological material after radiolabeling with avidin-biotin system

International Nuclear Information System (INIS)

Fan Wo; Qian Jianhua; Zhu Benxing

2003-01-01

To find a method for determining the immunoreactivity of monoclonal antibodies after radiolabeling avidin is unlabeled and labeled with Rodamine, 131 I and 188 Re, respectively. The affinities and half-desorbed amounts of biotin and four kinds of avidin are determined by the biotin columns plus non-labeled avidin (cold avidin). The affinities of biotin and avidin unlabeled and labeled with Rodamine, 188 Re and 131 I are decreased in turn. Their half-desorbed amounts from biotin are 21.9, 19.5, 25.7 and 47.9 μg of cold avidin. Two kinds of radiolabeled avidin have lower affinity with biotin than that of avidin unlabeled and labeled with Rodamine. There is a possibility to evaluate the reactivity of biological materials with different labeling methods by avidin-biotin system

Submicron hollow spot generation by solid immersion lens and structured illumination

NARCIS (Netherlands)

Kim, M.S.; Assafrao, A.C.; Scharf, T.; Wachters, A.J.H.; Pereira, S.F.; Urbach, H.P.; Brun, M.; Olivier, S.; Nicoletti, S.; Herzig, H.P.

2012-01-01

We report on the experimental and numerical demonstration of immersed submicron-size hollow focused spots, generated by structuring the polarization state of an incident light beam impinging on a micro-size solid immersion lens (?-SIL) made of SiO2. Such structured focal spots are characterized by a

A novel method of 18F radiolabeling for PET.

NARCIS (Netherlands)

McBride, W.J.; Sharkey, R.M.; Karacay, H.; D'Souza, C.A.; Rossi, E.A.; Laverman, P.; Chang, C.H.; Boerman, O.C.; Goldenberg, D.M.

2009-01-01

Small biomolecules are typically radiolabeled with (18)F by binding it to a carbon atom, a process that usually is designed uniquely for each new molecule and requires several steps and hours to produce. We report a facile method wherein (18)F is first attached to aluminum as Al(18)F, which is then

Organic aerosols

International Nuclear Information System (INIS)

Penner, J.E.

1994-01-01

Organic aerosols scatter solar radiation. They may also either enhance or decrease concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the sources of organic aerosol matter. The anthropogenic sources of organic aerosols may be as large as the anthropogenic sources of sulfate aerosols, implying a similar magnitude of direct forcing of climate. The source estimates are highly uncertain and subject to revision in the future. A slow secondary source of organic aerosols of unknown origin may contribute to the observed oceanic concentrations. The role of organic aerosols acting as cloud condensation nuclei (CCN) is described and it is concluded that they may either enhance or decrease the ability of anthropogenic sulfate aerosols to act as CCN

Chemical composition of aerosol particles and light extinction apportionment before and during the heating season in Beijing, China

Science.gov (United States)

Wang, Qingqing; Sun, Yele; Jiang, Qi; Du, Wei; Sun, Chengzhu; Fu, Pingqing; Wang, Zifa

2015-12-01

Despite extensive efforts into characterization of the sources and formation mechanisms of severe haze pollution in the megacity of Beijing, the response of aerosol composition and optical properties to coal combustion emissions in the heating season remain poorly understood. Here we conducted a 3 month real-time measurement of submicron aerosol (PM1) composition by an Aerosol Chemical Speciation Monitor and particle light extinction by a Cavity Attenuated Phase Shift extinction monitor in Beijing, China, from 1 October to 31 December 2012. The average (±σ) PM1 concentration was 82.4 (±73.1) µg/m3 during the heating period (HP, 15 November to 31 December), which was nearly 50% higher than that before HP (1 October to 14 November). While nitrate and secondary organic aerosol (SOA) showed relatively small changes, organics, sulfate, and chloride were observed to have significant increases during HP, indicating the dominant impacts of coal combustion sources on these three species. The relative humidity-dependent composition further illustrated an important role of aqueous-phase processing for the sulfate enhancement during HP. We also observed great increases of hydrocarbon-like OA (HOA) and coal combustion OA (CCOA) during HP, which was attributed to higher emissions at lower temperatures and coal combustion emissions, respectively. The relationship between light extinction and chemical composition was investigated using a multiple linear regression model. Our results showed that the largest contributors to particle extinction were ammonium nitrate (32%) and ammonium sulfate (28%) before and during HP, respectively. In addition, the contributions of SOA and primary OA to particle light extinction were quantified. The results showed that the OA extinction was mainly caused by SOA before HP and by SOA and CCOA during HP, yet with small contributions from HOA and cooking aerosol for the entire study period. Our results elucidate substantial changes of aerosol

Enhancement in electrical conductivity of pastes containing submicron Ag-coated Cu filler with palmitic acid surface modification

Science.gov (United States)

Choi, Eun Byeol; Lee, Jong-Hyun

2017-09-01

The fabrication and applied use of submicron Ag-coated Cu (Cu@Ag) particles as a filler material for epoxy-based conductive pastes having the advantages of a lower material cost and antioxidation behavior were studied. Submicron Cu@Ag particles were successfully prepared and surface-modified using palmitic acid. Diffuse reflectance infrared Fourier transform spectroscopy and thermogravimetric differential scanning calorimetry results indicated the formation of an organic layer by the chemical interaction between the Cu@Ag surface and palmitic acid and the survival of the organic layer after treatment at 160 °C for 3 h in air. The printed pastes containing both commercial micron Cu@Ag flakes and the fabricated submicron Cu@Ag particles showed a greatly reduced electrical resistivity (4.68 × 10-4 Ω cm) after surface modification compared to an initial value of 1.85 × 10-3 Ω cm when cured.

Radiolabeled cypoxic cell sensitizers: tracer for assessment of ischemia

International Nuclear Information System (INIS)

Mathias, C.J.; Welch, M.J.; Kilbourn, M.R.; Jerabek, P.A.; Patrick, T.B.; Raichle, M.E.; Krohn, K.A.; Rasey, J.S.; Shaw, D.W.

1987-01-01

Hypoxic, non-functional, but viable, tissue may exist in heart and brain following an arterial occlusion. Identification of such tissue in vivo is crucial to the development of effective treatment strategies. It has been suggested that certain compounds capable of sensitizing hypoxic tumor cells to killing by x-rays (i.e., misonidazole) might serve as in vivo markers of hypoxic tissue in ischemic myocardium or brain if properly radiolabeled. To this end the authors have radiolabeled two fluorinated analogs of nitroimidazole based hypoxic cell sensitizers with the 110 minute half-lived positron-emitting fluorine-18. The ability of these tracers to quantitate the presence of hypoxic tissue has been studied in a gerbil stroke model. The in vivo uptake of one of these tracers [F-18]-fluoronormethyoxymisonidazole is dependent on the extent of tissue hypoxia, and thus, appears to have potential as a diagnostic indicator of non-functional but viable tissue when the tracer is used in conjunction with positron emission tomography. 80 references, 2 figures, 1 table

Radiolabeled cholesteryl ethers: A need to analyze for biological stability before use.

Science.gov (United States)

Manual Kollareth, Denny Joseph; Chang, Chuchun L; Hansen, Inge H; Deckelbaum, Richard J

2018-03-01

Radiolabeled cholesteryl ethers are widely used as non-metabolizable tracers for lipoproteins and lipid emulsions in a variety of in vitro and in vivo experiments. Since cholesteryl ethers do not leave cells after uptake and are not hydrolyzed by mammalian cellular enzymes, these compounds can act as markers for cumulative cell uptakes of labeled particles. We have employed [ 3 H]cholesteryl oleoyl ether to study the uptake and distribution of triglyceride-rich emulsion particles on animal models. However, questionable unexpected results compelled us to analyze the stability of these ethers. We tested the stability of two commercially available radiolabeled cholesteryl ethers - [ 3 H]cholesteryl oleoyl ether and [ 3 H]cholesteryl hexadecyl ether from different suppliers, employing in vitro , in vivo and chemical model systems. Our results show that, among the two cholesteryl ethers tested, one ether was hydrolyzed to free cholesterol in vitro , in vivo and chemically under alkaline hydrolyzing agent. Free cholesterol, unlike cholesteryl ether, can then re-enter the circulation leading to confounding results. The other ether was not hydrolyzed to free cholesterol and remained as a stable ether. Hence, radiolabeled cholesteryl ethers should be analyzed for biological stability before utilizing them for in vitro or in vivo experiments.

Research on aerosol formation, aerosol behaviour, aerosol filtration, aerosol measurement techniques and sodium fires at the Laboratory for Aerosol Physics and Filter Technology at the Nuclear Research Center Karlsruhe

Energy Technology Data Exchange (ETDEWEB)

Jordan, S; Schikarski, W; Schoeck, W [Gesellschaft fuer Kernforschung mbH, Karlsruhe (Germany)

1977-01-01

The behaviour of aerosols in LMFBR plant systems is of great importance for a number of problems, both normal operational and accident kind. This paper covers the following: aerosol modelling for LMFBR containment systems; aerosol size spectrometry by laser light scattering; experimental facilities and experimental results concerned with aerosol release under accident conditions; filtration of sodium oxide aerosols by multilayer sand bed filters.

Research on aerosol formation, aerosol behaviour, aerosol filtration, aerosol measurement techniques and sodium fires at the Laboratory for Aerosol Physics and Filter Technology at the Nuclear Research Center Karlsruhe

International Nuclear Information System (INIS)

Jordan, S.; Schikarski, W.; Schoeck, W.

1977-01-01

The behaviour of aerosols in LMFBR plant systems is of great importance for a number of problems, both normal operational and accident kind. This paper covers the following: aerosol modelling for LMFBR containment systems; aerosol size spectrometry by laser light scattering; experimental facilities and experimental results concerned with aerosol release under accident conditions; filtration of sodium oxide aerosols by multilayer sand bed filters

Radiolabelled blood cells

Energy Technology Data Exchange (ETDEWEB)

Lavender, J.P.

1986-12-01

After the introduction of gamma-emitting labels for blood-cells the use of radio-labelled blood cells is not only limited to kinetics of blood cells but it is also possible to localise inflammations, abscesses and thrombus. The most commonly applied label for red cells is Tc-99m. The most widely used technique for labelling granulocytes or platelets is In-111-oxine. In future the labelling of blood cells will be more simple and more specific due to monoclonal antibodies onto the platelet or the granulocyte cell surface. Labelled red cells have their main application in blood-pool imaging and in localisation of gastrointestinal bleeding. Besides the determination of the platelet life-span in haematologic disorders labelled platelets allow to localise thrombus and to show abnormal vasculature in the rejecting kidney. The commonest application for In-111-oxin labelled granulocytes is to show abdominal inflammations to localise inflamed bowel segments and to assess the inflammatory activity in chronic inflammatory bowel diseases. Moreover brain abscesses, bone sepsis and lung sepsis can be identified.

Hygroscopic Behavior of Multicomponent Aerosols Involving NaCl and Dicarboxylic Acids.

Science.gov (United States)

Peng, Chao; Jing, Bo; Guo, Yu-Cong; Zhang, Yun-Hong; Ge, Mao-Fa

2016-02-25

Atmospheric aerosols are usually complex mixtures of inorganic and organic compounds. The hygroscopicity of mixed particles is closely related to their chemical composition and interactions between components, which is still poorly understood. In this study, the hygroscopic properties of submicron particles composed of NaCl and dicarboxylic acids including oxalic acid (OA), malonic acid (MA), and succinic acid (SA) with various mass ratios are investigated with a hygroscopicity tandem differential mobility analyzer (HTDMA) system. Both the Zdanovskii-Stokes-Robinson (ZSR) method and extended aerosol inorganics model (E-AIM) are applied to predict the water uptake behaviors of sodium chloride/dicarboxylic acid mixtures. For NaCl/OA mixed particles, the measured growth factors were significantly lower than predictions from the model methods, indicating a change in particle composition caused by chloride depletion. The hygroscopic growth of NaCl/MA particles was well described by E-AIM, and that of NaCl/SA particles was dependent upon mixing ratio. Compared with model predictions, it was determined that water uptake of the NaCl/OA mixture could be enhanced and could be closer to the predictions by addition of levoglucosan or malonic acid, which retained water even at low relative humidity (RH), leading to inhibition of HCl evaporation during dehydration. These results demonstrate that the coexisting hygroscopic species have a strong influence on the phase state of particles, thus affecting chemical interactions between inorganic and organic compounds as well as the overall hygroscopicity of mixed particles.

Aerosol characterization over the southeastern United States using high-resolution aerosol mass spectrometry: spatial and seasonal variation of aerosol composition and sources with a focus on organic nitrates

Science.gov (United States)

Xu, L.; Suresh, S.; Guo, H.; Weber, R. J.; Ng, N. L.

2015-07-01

We deployed a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aerosol Chemical Speciation Monitor (ACSM) to characterize the chemical composition of submicron non-refractory particulate matter (NR-PM1) in the southeastern USA. Measurements were performed in both rural and urban sites in the greater Atlanta area, Georgia (GA), and Centreville, Alabama (AL), for approximately 1 year as part of Southeastern Center for Air Pollution and Epidemiology study (SCAPE) and Southern Oxidant and Aerosol Study (SOAS). Organic aerosol (OA) accounts for more than half of NR-PM1 mass concentration regardless of sampling sites and seasons. Positive matrix factorization (PMF) analysis of HR-ToF-AMS measurements identified various OA sources, depending on location and season. Hydrocarbon-like OA (HOA) and cooking OA (COA) have important, but not dominant, contributions to total OA in urban sites (i.e., 21-38 % of total OA depending on site and season). Biomass burning OA (BBOA) concentration shows a distinct seasonal variation with a larger enhancement in winter than summer. We find a good correlation between BBOA and brown carbon, indicating biomass burning is an important source for brown carbon, although an additional, unidentified brown carbon source is likely present at the rural Yorkville site. Isoprene-derived OA factor (isoprene-OA) is only deconvolved in warmer months and contributes 18-36 % of total OA. The presence of isoprene-OA factor in urban sites is more likely from local production in the presence of NOx than transport from rural sites. More-oxidized and less-oxidized oxygenated organic aerosol (MO-OOA and LO-OOA, respectively) are dominant fractions (47-79 %) of OA in all sites. MO-OOA correlates well with ozone in summer but not in winter, indicating MO-OOA sources may vary with seasons. LO-OOA, which reaches a daily maximum at night, correlates better with estimated nitrate functionality from organic nitrates than total nitrates. Based

Characterization of Aerosols Containing Zn, Pb, and Cl from an Industrial Region of Mexico City

International Nuclear Information System (INIS)

Moffet, Ryan C.; Desyaterik, Yury; Hopkins, Rebecca J.; Tivanski, Alexei V.; Gilles, Marry K.; Wang, Yan A.; Shutthanandan, V.; Molina, Luisa T.; Abraham, Rodrigo G.; Johnson, Kirsten S.; Mugica, Violeta; Molina, Mario J.; Laskin, Alexander; Prather, Kimberly A.

2008-01-01

During the March, 2006 MILAGRO campaign, measurements in the Northern Mexico City Metropolitan Area revealed the frequent appearance of particles with a characteristically high content of internally mixed Zn, Pb, Cl, and P. A comprehensive study of the chemical and physical properties of these particles was performed using a complementary combination of aerosol measurement techniques. Individual particles were analyzed using Aerosol Time-of-Flight Mass Spectrometry (ATOFMS) and Computer Controlled Scanning Electron Microscopy/Energy Dispersive X-Ray spectroscopy (CCSEM/EDX). Proton Induced X-Ray Emission (PIXE) analysis of bulk aerosol samples provided time-resolved mass concentrations of individual elements. The PIXE measurements indicated that Zn is more strongly correlated with Cl than with any other element and that Zn concentrations are higher than other non-ferrous transition metals. The Zn- and Pb-containing particles have both spherical and non-spherical morphologies. Many metal rich particles had needle-like structures and were found to be composed of ZnO and/or Zn(NO3)2 6H2O as indicated by scanning transmission x-ray microscopy/near edge X-ray absorption spectroscopy (STXM/NEXAFS). The Zn and Pb rich particles were primarily in the submicron size range and internally mixed with elemental carbon. The unique chemical associations most closely match signatures acquired for garbage incineration. This unique combination of complementary analytical techniques has allowed for a comprehensive evaluation of Zn- and Pb- containing particles in a complex urban environment, highlighting unique characteristics that give powerful insight into their origin

Size resolved mass concentration and elemental composition of atmospheric aerosols over the Eastern Mediterranean area

Directory of Open Access Journals (Sweden)

J. Smolík

2003-01-01

Full Text Available A Berner low pressure impactor was used to collect size-segregated aerosol samples at Finokalia, located on the north-eastern coast of Crete, Greece during July 2000 and January 2001. Several samples were also collected during the summer campaign aboard the research vessel "AEGAIEO" in the Aegean Sea. Gravimetric analysis and inversion techniques yielded daily PM1 and PM10 mass concentrations. The samples were also analysed by PIXE giving the elemental size distributions of Al, Si, K, Ca, Ti, Mn, Fe, Sr, S, Cl, Ni, V, Cu, Cr, Zn, and Pb. The crustal elements and sea-salt had a unimodal supermicron size distribution. Sulphur was found predominantly in submicron fractions. K, V, and Ni exhibited a bimodal distribution with a submicron mode produced by forest fires and oil combustion. The anthropogenic elements had broad and not well-defined distributions. The time series for PM1 and PM10 mass and elemental concentrations showed both daily and seasonal variation. Higher mass concentrations were observed during two incursions of Saharan dust, whilst higher concentrations of S, Cu, Zn, and Pb were encountered in samples collected in air masses arriving from northern Greece or the western coast of Turkey. Elevated concentrations of chlorine were found in samples with air masses either originating above the Atlantic Ocean and arriving at Finokalia via western Europe or recirculating over the western coast of the Black Sea.

Calibration of aerosol radiometers. Special aerosol sources

International Nuclear Information System (INIS)

Belkina, S.K.; Zalmanzon, Yu.E.; Kuznetsov, Yu.V.; Fertman, D.E.

1988-01-01

Problems of calibration of artificial aerosol radiometry and information-measurement systems of radiometer radiation control, in particular, are considered. Special aerosol source is suggested, which permits to perform certification and testing of aerosol channels of the systems in situ without the dismantling

Extraction, radiolabeling and in vivo biological evaluation of {sup 131}I labeled egonol glycosides extract