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Sample records for exhaust particles activate

  1. Health effects of exhaust particles

    Energy Technology Data Exchange (ETDEWEB)

    Pihlava, T.; Uuppo, M.; Niemi, S.

    2013-11-01

    , they can migrate far away from their source and they can even spread into the blood circulation and the brain. Transition metals on the surface of particles together with carcinogenic compounds found in the PM have been shown to cause cancer. Diesel ultra-fine particles are mainly elemental carbon, organic carbon and sulphuric acid. Sulphur still exists in diesel fuel in certain regions and if the amount of sulphur in the fuel is reduced, particles are reduced as well. Metallic compounds originate mainly from the lubrication oil, but also from the fuel and engine wear. In urban areas the amounts of particles are usually higher than in rural areas. Regulations for air quality in urban areas have been set to protect people living in the cities. Regulations are also becoming stricter in the field of internal combustion engines and particle numbers along with their mass are regulated in the EURO 6 standard. Diesel PM can be reduced by several means. Reformulating the fuel and lubrication oil directly influences PM emissions while different aftertreatment systems can be used to remove PM from the engine exhaust gases. With a well-optimized injection system, burning is more complete and PM emissions are also reduced. Exposure to particles can be decreased by avoiding busy roads where the level of particles is usually high, having a hobby that involves less exertion and decreasing exercise time. Outdoor activities should be reduced when PM concentration in the air is high. (orig.)

  2. Regulation of human hepatic drug transporter activity and expression by diesel exhaust particle extract.

    Directory of Open Access Journals (Sweden)

    Marc Le Vee

    Full Text Available Diesel exhaust particles (DEPs are common environmental air pollutants primarily affecting the lung. DEPs or chemicals adsorbed on DEPs also exert extra-pulmonary effects, including alteration of hepatic drug detoxifying enzyme expression. The present study was designed to determine whether organic DEP extract (DEPe may target hepatic drug transporters that contribute in a major way to drug detoxification. Using primary human hepatocytes and transporter-overexpressing cells, DEPe was first shown to strongly inhibit activities of the sinusoidal solute carrier (SLC uptake transporters organic anion-transporting polypeptides (OATP 1B1, 1B3 and 2B1 and of the canalicular ATP-binding cassette (ABC efflux pump multidrug resistance-associated protein 2, with IC50 values ranging from approximately 1 to 20 μg/mL and relevant to environmental exposure situations. By contrast, 25 μg/mL DEPe failed to alter activities of the SLC transporter organic cation transporter (OCT 1 and of the ABC efflux pumps P-glycoprotein and bile salt export pump (BSEP, whereas it only moderately inhibited those of sodium taurocholate co-transporting polypeptide and of breast cancer resistance protein (BCRP. Treatment by 25 μg/mL DEPe was next demonstrated to induce expression of BCRP at both mRNA and protein level in cultured human hepatic cells, whereas it concomitantly repressed mRNA expression of various transporters, including OATP1B3, OATP2B1, OCT1 and BSEP. Such changes in transporter expression were found to be highly correlated to those caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, a reference activator of the aryl hydrocarbon receptor (AhR pathway. This suggests that DEPe, which is enriched in known ligands of AhR like polycyclic aromatic hydrocarbons, alters drug transporter expression via activation of the AhR cascade. Taken together, these data established human hepatic transporters as targets of organic chemicals containing in DEPs, which may contribute

  3. Toxicity of Exhaust Gases and Particles from IC-Engines -- International Activities Survey (EngToxIn)

    Energy Technology Data Exchange (ETDEWEB)

    Czerwinski, J. [University for Applied Sciences, Biel-Bienne (Switzerland)

    2011-09-15

    Exhaust gases from engines, as well as from other combustion -- and industrial processes contain different gaseous, semi volatile and solid compounds which are toxic. Some of these compounds are not regarded by the respective legislations; some new substances may appear, due to the progressing technical developments and new systems of exhaust gas aftertreatment. The toxical effects of exhaust gases as whole aerosols (i.e. all gaseous components together with particle matter and nanoparticles) can be investigated in a global way, by exposing the living cells, or cell cultures to the aerosol, which means a simultaneous superposition of all toxic effects from all active components. On several places researchers showed, that this method offers more objective results of validation of toxicity, than other methods used up to date. It also enables a relatively quick insight in the toxic effects with consideration of all superimposed influences of the aerosol. This new methodology can be applied for all kinds of emission sources. It bears potentials of giving new contributions to the present state of knowledge in this domain and can in some cases lead to a change of paradigma. The present report gives short information about the activities concerning the research on toxicity of exhaust gases from IC-engines in different countries. It also gives some ideas about research of information sources. It can be stated that there are worldwide a lot of activities concerning health effects. They have different objectives, different approaches and methodologies and rarely the results can be directly compared to each other. Nevertheless there also are some common lines and with appropriate efforts there are possible ways to establish the harmonised biological test procedures.

  4. DNA adducts induced by in vitro activation of extracts of diesel and biodiesel exhaust particles

    Science.gov (United States)

    AbstractContext: Biodiesel and biodiesel-blend fuels offer a renewable alternative to petroleum diesel, but few data are available concerning the carcinogenic potential of biodiesel exhausts. Objectives: We compared the formation of covalent DNA adducts by the in vitro metabol...

  5. GASOLINE VEHICLE EXHAUST PARTICLE SAMPLING STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Kittelson, D; Watts, W; Johnson, J; Zarling, D Schauer,J Kasper, K; Baltensperger, U; Burtscher, H

    2003-08-24

    The University of Minnesota collaborated with the Paul Scherrer Institute, the University of Wisconsin (UWI) and Ricardo, Inc to physically and chemically characterize the exhaust plume from recruited gasoline spark ignition (SI) vehicles. The project objectives were: (1) Measure representative particle size distributions from a set of on-road SI vehicles and compare these data to similar data collected on a small subset of light-duty gasoline vehicles tested on a chassis dynamometer with a dilution tunnel using the Unified Drive Cycle, at both room temperature (cold start) and 0 C (cold-cold start). (2) Compare data collected from SI vehicles to similar data collected from Diesel engines during the Coordinating Research Council E-43 project. (3) Characterize on-road aerosol during mixed midweek traffic and Sunday midday periods and determine fleet-specific emission rates. (4) Characterize bulk- and size-segregated chemical composition of the particulate matter (PM) emitted in the exhaust from the gasoline vehicles. Particle number concentrations and size distributions are strongly influenced by dilution and sampling conditions. Laboratory methods were evaluated to dilute SI exhaust in a way that would produce size distributions that were similar to those measured during laboratory experiments. Size fractionated samples were collected for chemical analysis using a nano-microorifice uniform deposit impactor (nano-MOUDI). In addition, bulk samples were collected and analyzed. A mixture of low, mid and high mileage vehicles were recruited for testing during the study. Under steady highway cruise conditions a significant particle signature above background was not measured, but during hard accelerations number size distributions for the test fleet were similar to modern heavy-duty Diesel vehicles. Number emissions were much higher at high speed and during cold-cold starts. Fuel specific number emissions range from 1012 to 3 x 1016 particles/kg fuel. A simple

  6. Bronchoalveolar inflammation after exposure to diesel exhaust: comparison between unfiltered and particle trap filtered exhaust.

    Science.gov (United States)

    Rudell, B; Blomberg, A; Helleday, R; Ledin, M C; Lundbäck, B; Stjernberg, N; Hörstedt, P; Sandström, T

    1999-08-01

    Air pollution particulates have been identified as having adverse effects on respiratory health. The present study was undertaken to further clarify the effects of diesel exhaust on bronchoalveolar cells and soluble components in normal healthy subjects. The study was also designed to evaluate whether a ceramic particle trap at the end of the tail pipe, from an idling engine, would reduce indices of airway inflammation. The study comprised three exposures in all 10 healthy never smoking subjects; air, diluted diesel exhaust, and diluted diesel exhaust filtered with a ceramic particle trap. The exposures were given for 1 hour in randomised order about 3 weeks apart. The diesel exhaust exposure apperatus has previously been carefully developed and evaluated. Bronchoalveolar lavage was performed 24 hours after exposures and the lavage fluids from the bronchial and bronchoalveolar region were analysed for cells and soluble components. The particle trap reduced the mean steady state number of particles by 50%, but the concentrations of the other measured compounds were almost unchanged. It was found that diesel exhaust caused an increase in neutrophils in airway lavage, together with an adverse influence on the phagocytosis by alveolar macrophages in vitro. Furthermore, the diesel exhaust was found to be able to induce a migration of alveolar macrophages into the airspaces, together with reduction in CD3+CD25+ cells. (CD = cluster of differentiation) The use of the specific ceramic particle trap at the end of the tail pipe was not sufficient to completely abolish these effects when interacting with the exhaust from an idling vehicle. The current study showed that exposure to diesel exhaust may induce neutrophil and alveolar macrophage recruitment into the airways and suppress alveolar macrophage function. The particle trap did not cause significant reduction of effects induced by diesel exhaust compared with unfiltered diesel exhaust. Further studies are warranted to

  7. The activation of NLRP3-inflammsome by stimulation of diesel exhaust particles in lung tissues from emphysema model and RAW 264.7 cell line.

    Science.gov (United States)

    Uh, Soo-Taek; Koo, So My; Kim, Yangki; Kim, Kiup; Park, Sungwoo; Jang, An Soo; Kim, Dojin; Kim, Yong Hoon; Park, Choon-Sik

    2017-09-01

    Diesel exhaust particles (DEPs) lead to elevation of reactive oxygen species, which can activate the nucleotide-binding oligomerization domain-like receptor (NLR) family members containing the pyrin domain 3 (NLRP3)-inf lammasome. In this study, we elucidated whether NLRP3 -inf lammasome is activated by DEPs and whether antioxidants (N-acetylcysteine [NAC]) could inhibit such activation. RAW 264.7 cells and ex vivo lung tissues explants obtained from elastase-induced emphysema animal models were stimulated with cigarette smoking extract (CSE), DEPs, and lipopolysaccharide, and levels of interleukin-1β (IL-1β), caspase-1 and nucleotide-binding oligomerization domain-like receptor (NLR) family members containing the pyrin domain (NLRP3)-inflammasome were assessed by Western blotting and immunohistochemistry. NAC and caspase-1 inhibitor suppressed CSE- and DEP-induced secretion of IL-1β in RAW 264.7 cells. The expression levels of the NLRP3-inflammasome and caspase-1 were upregulated in RAW 264.7 cells by stimulation with CSE and DEPs and were inhibited by NAC. CSE and DEPs increased the secretion of IL-1β in lung tissues from both the normal and elastase-induced emphysema groups. The secretion of IL-1β by CSE and DEPs was increased in the elastin-induced emphysema group more than that in the normal group (CSE: 309 ± 19 pg/mL vs. 151 ± 13 pg/mL, respectively, p NLRP3-inflammasome expression as determined by immunohistochemistry was increased by CSE and DEPs in both the normal and elastin-induced emphysema groups, and was suppressed by NAC. The NLRP3-inf lammasome is activated by DEPs in ex vivo tissue explants from elastase-induced emphysema animal model, and this activation is inhibited by NAC.

  8. Diesel exhaust particle exposure in vitro alters monocyte differentiation and function.

    Directory of Open Access Journals (Sweden)

    Nazia Chaudhuri

    Full Text Available Air pollution by diesel exhaust particles is associated with elevated mortality and increased hospital admissions in individuals with respiratory diseases such as asthma and chronic obstructive pulmonary disease. During active inflammation monocytes are recruited to the airways and can replace resident alveolar macrophages. We therefore investigated whether chronic fourteen day exposure to low concentrations of diesel exhaust particles can alter the phenotype and function of monocytes from healthy individuals and those with chronic obstructive pulmonary disease. Monocytes were purified from the blood of healthy individuals and people with a diagnosis of chronic obstructive pulmonary disease. Monocyte-derived macrophages were generated in the presence or absence of diesel exhaust particles and their phenotypes studied through investigation of their lifespan, cytokine generation in response to Toll like receptor agonists and heat killed bacteria, and expression of surface markers. Chronic fourteen day exposure of monocyte-derived macrophages to concentrations of diesel exhaust particles >10 µg/ml caused mitochondrial and lysosomal dysfunction, and a gradual loss of cells over time both in healthy and chronic obstructive pulmonary disease individuals. Chronic exposure to lower concentrations of diesel exhaust particles impaired CXCL8 cytokine responses to lipopolysaccharide and heat killed E. coli, and this phenotype was associated with a reduction in CD14 and CD11b expression. Chronic diesel exhaust particle exposure may therefore alter both numbers and function of lung macrophages differentiating from locally recruited monocytes in the lungs of healthy people and patients with chronic obstructive pulmonary disease.

  9. Space Shuttle exhausted aluminum oxide - A measured particle size distribution

    Science.gov (United States)

    Cofer, W. R., III; Purgold, G. C.; Edahl, R. A.; Winstead, E. L.

    1991-01-01

    Aluminum oxide (A2O3) particles were collected from the Space Shuttle exhaust plume immediately following the launch of STS-34 on October 18, 1989. A2O3 samples were obtained at 2.4, 3.0, 3.2, and 7.4 km in altitude. The samples were analyzed using SEM to develope particle size distributions. There were no indications that the particle size distribution changed as a function of altitude. The particle number concentrations per cubic meter of air sampled for the four collections was found to fit an exponential expression.

  10. Mutagenicity of Diesel and Soy Biodiesel Exhaust Particles

    Science.gov (United States)

    Mutagenicity Of Diesel And Soy Biodiesel Exhaust Particles E Mutlua,b' SH Warrenb, PP Matthewsb, CJ Kingb, B Prestonc, MD Haysb, DG Nashb,ct, WP Linakb, MI Gilmourb, and DM DeMarinib aUniversity of North Carolina, Chapel Hill, NC bU.S. Environmental Agency, Research Triangle Pa...

  11. Toxicity of Exhaust Gases and Particles from IC-Engines – International Activities Survey (EngToxIn). 2nd Information Report for IEA Implementing Agreement AMF

    Energy Technology Data Exchange (ETDEWEB)

    Czerwinski, J. [University for Applied Sciences, Biel-Bienne (Switzerland)

    2012-10-15

    Exhaust gases from engines, as well as from other technical combustion processes contain gaseous, semi volatile and solid compounds which are toxic. Some of these compounds are not yet limited by the respective legislations; but may need to be based on ongoing health research findings and some new substances did appear recently, due to the progressing technical developments providing new systems of exhaust gas aftertreatment. A new approach described here is that the toxic effects of exhaust gases as an aerosol containing gaseous components as well as particulate matter and nanoparticles can be investigated in a global way, by exposing the living cells, or cell cultures to the aerosol, which means a simultaneous superposition of all toxic effects from all active components. At several research sites it has been showed, that this method offers more objective results of validation of toxicity, than other methods used until now. It also enables a relatively quick insight in the toxic effects with consideration of all superimposed influences of the aerosol. This new methodology can be applied for all kinds of emission sources. It also bears the potential of giving new contributions to the present state of knowledge in this domain and can in some cases lead to a change of paradigma. The present report gives information about activities concerning the research on toxicity of exhaust gases from IC-engines in different countries. It also gives some ideas about the available information sources. The general situation and the basic information have not changed much so the chapters 1 and 2 are repeated from the last year report, [1] with only a few modifications. We observe fast increasing research activities concerning health effects worldwide. They have different objectives, different approaches and methodologies and sometimes the results can be directly compared to each other. There are mostly common lines and with appropriate efforts there might be possible ways to

  12. In situ exhaust cloud measurements. [particle size distribution and cloud physics of rocket exhaust clouds

    Science.gov (United States)

    Wornom, D.

    1980-01-01

    Airborne in situ exhaust cloud measurements were conducted to obtain definitions of cloud particle size range, Cl2 content, and HCl partitioning. Particle size distribution data and Cl2 measurements were made during the May, August, and September 1977 Titan launches. The measurements of three basic effluents - HCl, NO sub X, and particles - against minutes after launch are plotted. The maximum observed HCl concentration to the maximum Cl2 concentration are compared and the ratios of the Cl2 to the HCl is calculated.

  13. Active particles

    CERN Document Server

    Degond, Pierre; Tadmor, Eitan

    2017-01-01

    This volume collects ten surveys on the modeling, simulation, and applications of active particles using methods ranging from mathematical kinetic theory to nonequilibrium statistical mechanics. The contributing authors are leading experts working in this challenging field, and each of their chapters provides a review of the most recent results in their areas and looks ahead to future research directions. The approaches to studying active matter are presented here from many different perspectives, such as individual-based models, evolutionary games, Brownian motion, and continuum theories, as well as various combinations of these. Applications covered include biological network formation and network theory; opinion formation and social systems; control theory of sparse systems; theory and applications of mean field games; population learning; dynamics of flocking systems; vehicular traffic flow; and stochastic particles and mean field approximation. Mathematicians and other members of the scientific commu...

  14. Neural activation in stress-related exhaustion

    DEFF Research Database (Denmark)

    Gavelin, Hanna Malmberg; Neely, Anna Stigsdotter; Andersson, Micael

    2017-01-01

    The primary purpose of this study was to investigate the association between burnout and neural activation during working memory processing in patients with stress-related exhaustion. Additionally, we investigated the neural effects of cognitive training as part of stress rehabilitation. Fifty......-five patients with clinical diagnosis of exhaustion disorder were administered the n-back task during fMRI scanning at baseline. Ten patients completed a 12-week cognitive training intervention, as an addition to stress rehabilitation. Eleven patients served as a treatment-as-usual control group. At baseline...

  15. Diesel exhaust particles induce the over expression of tumor necrosis factor-alpha (TNF-alpha) gene in alvelor machrophage and failed to induce apoptosis through activation of nuclear factor-kappaB (NF-kappaB)

    Science.gov (United States)

    Exposure to particulate matter (PM2.5-10), including diesel exhaust particles (DEP) has been reported to induce lung injury and exacerbation of asthma and chronic obstructive pulmonary disease. Alveolar macrophages play a major role in the lung's response to inhaled particles and...

  16. Mutagenicity of diesel exhaust particles from an engine with differing exhaust after treatments.

    Science.gov (United States)

    Shi, X-C; Keane, M J; Ong, T; Li, S-Q; Bugarski, A B

    2010-01-01

    This study was conducted to investigate the effects of engine operating conditions and exhaust aftertreatments on the mutagenicity of diesel particulate matter (DPM) collected directly in an underground mine environment. A number of after-treatment devices are currently used on diesel engines in mines, but it is critical to determine whether reductions in DPM concentrations result in a corresponding decrease in adverse health effects. An eddy-current dynamometer was used to operate naturally aspirated mechanically controlled engine at several steady-state conditions. The samples were collected when the engine was equipped with a standard muffler, a diesel oxidation catalytic converter, two types of uncatalyzed diesel particulate filter systems, and three types of disposable diesel particulate filter elements. Bacterial gene mutation activity of DPM was tested on acetone extracts using the Ames Salmonella assay. The results indicated strong correlation between engine operating conditions and mutagenic activity of DPM. When the engine was fitted with muffler, the mutagenic activity was observed for the samples collected from light-load, but not heavy-load operating conditions. When the engine was equipped with a diesel oxidation catalyst, the samples did not exhibit mutagenic activity for any of four engine operating conditions. Mutagenic activity was observed for the samples collected when the engine was retrofitted with three types of disposable filters and sintered metal diesel particulate filter and operated at light load conditions. However, those filtration systems substantially reduced the concentration-normalized mutagenic activity from the levels observed for the muffler.

  17. Prenatal exposure to diesel exhaust particles and effect on the male reproductive system in mice

    DEFF Research Database (Denmark)

    Hemmingsen, Jette Gjerke; Hougaard, Karin Sørig; Talsness, Chris

    2009-01-01

    In utero exposure to diesel exhaust particles may reduce sperm production in adulthood. We investigated the effect of prenatal exposure to diesel exhaust particles on the male reproductive system and assessed endocrine disruption and regulation of aquaporin expression as possible mechanisms...... of action. Dams inhaled 20 mg/m(3) of diesel exhaust particle standard reference material 2975 (SRM2975) or clean air for 1h/day on day 7-19 during pregnancy. Male offspring were killed on day 170 after birth. The dams that had inhaled SRM2975 delivered offspring, which in adulthood had reduced daily sperm...

  18. Physicochemical characterisation of combustion particles from vehicle exhaust and residential wood smoke

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    Schwarze Per E

    2006-01-01

    Full Text Available Abstract Background Exposure to ambient particulate matter has been associated with a number of adverse health effects. Particle characteristics such as size, surface area and chemistry seem to influence the negative effects of particles. In this study, combustion particles from vehicle exhaust and wood smoke, currently used in biological experiments, were analysed with respect to microstructure and chemistry. Methods Vehicle exhaust particles were collected in a road tunnel during two seasons, with and without use of studded tires, whereas wood smoke was collected from a stove with single-stage combustion. Additionally, a reference diesel sample (SRM 2975 was analysed. The samples were characterised using transmission electron microscopy techniques (TEM/HRTEM, EELS and SAED. Furthermore, the elemental and organic carbon fractions were quantified using thermal optical transmission analysis and the content of selected PAHs was determined by gas chromatography-mass spectrometry. Results Carbon aggregates, consisting of tens to thousands of spherical primary particles, were the only combustion particles identified in all samples using TEM. The tunnel samples also contained mineral particles originating from road abrasion. The geometric diameters of primary carbon particles from vehicle exhaust were found to be significantly smaller (24 ± 6 nm than for wood smoke (31 ± 7 nm. Furthermore, HRTEM showed that primary particles from both sources exhibited a turbostratic microstructure, consisting of concentric carbon layers surrounding several nuclei in vehicle exhaust or a single nucleus in wood smoke. However, no differences were detected in the graphitic character of primary particles from the two sources using SAED and EELS. The total PAH content was higher for combustion particles from wood smoke as compared to vehicle exhaust, whereas no source difference was found for the ratio of organic to total carbon. Conclusion Combustion particles from

  19. Diesel Exhaust Particles Induce the Over expression of Tumor Necrosis Factor-α (TNF-α) Gene in Alveolar Macrophages and Failed to Induce Apoptosis through Activation of Nuclear Factor-κB (NF-κB)

    Science.gov (United States)

    Kafoury, Ramzi M.; Madden, Michael C.

    2005-01-01

    Exposure to particulate matter (PM2.5–10), including diesel exhaust particles (DEP) has been reported to induce lung injury and exacerbation of asthma and chronic obstructive pulmonary disease. Alveolar macrophages play a major role in the lung’s response to inhaled particles and therefore, are a primary target for PM2.5–10 effect. The molecular and cellular events underlying DEP-induced toxicity in the lung, however, remain unclear. To determine the effect of DEP on alveolar macrophages, RAW 264.7 cells were grown in RPMI 1640 with supplements until confluency. RAW 264.7 cultures were exposed to Hank’s buffered saline solution (vehicle), vehicle containing an NF-κB inhibitor, BAY11-7082 (25μM with 11/2 hr pre-incubation), or vehicle containing DEP (250μg/ml) in the presence or absence of BAY11-7082 (25μM with 11/2 hr pre-incubation) for 4 hr and TNF-α release was determined by enzyme-linked immunosorbent assay and confirmed by western blots. RAW 264.7 apoptotic response was determined by DNA fragmentation assays. U937 cells treated with campothecin (4 μg/ml × 3 hr), an apoptosis-inducing agent, were used as positive control. We report that exposure to the carbonaceous core of DEP induces significant release of TNF-α in a concentration-dependent fashion (31 ± 4 pg/ml, n = 4, p = 0.08; 162 ± 23 pg/ml, n = 4, p < 0.05; 313 ± 31 pg/ml, n = 4, p < 0.05 at 25, 100, and 250 μg/ml, respectively). DEP exposure, however, failed to induce any apoptotic response in RAW 264.7 cells. Moreover, inhibition of NF-κB binding activity has resulted in DEP-induced apoptotic response in alveolar macrophages, as demonstrated by the NF-κB inhibitor, BAY11-7082 studies. The results of the present study indicate that DEP induce the release of TNF-α in alveolar macrophages, a primary target for inhaled particles effect. DEP-induced TNF-α gene expression is regulated at the transcriptional level by NF-κB. Furthermore, DEP-induced increase in NF-κB-DNA binding

  20. Model studies of volatile diesel exhaust particle formation: organic vapours involved in nucleation and growth?

    Science.gov (United States)

    Pirjola, L.; Karl, M.; Rönkkö, T.; Arnold, F.

    2015-02-01

    High concentration of volatile nucleation mode particles (NUP) formed in the atmosphere during exhaust cools and dilutes have hazardous health effects and impair visibility in urban areas. Nucleation mechanisms in diesel exhaust are only poorly understood. We performed model studies using two sectional aerosol dynamics process models AEROFOR and MAFOR on the formation of particles in the exhaust of a diesel engine, equipped with an oxidative after-treatment system and running with low fuel sulphur content (FSC), under laboratory sampling conditions where the dilution system mimics real-world conditions. Different nucleation mechanisms were tested; based on the measured gaseous sulphuric acid (GSA) and non-volatile core and soot particle number concentrations of the raw exhaust, the model simulations showed that the best agreement between model predictions and measurements in terms of particle number size distribution was obtained by barrierless heteromolecular homogeneous nucleation between GSA and semi-volatile organic vapour (for example adipic acid) combined with the homogeneous nucleation of GSA alone. Major growth of the particles was predicted to occur by the same organic vapour at concentrations of (1-2) ×1012cm-3. The pre-existing core and soot mode concentrations had opposite trend on the NUP formation, and maximum NUP formation was predicted if a diesel particle filter (DPF) was used. On the other hand, NUP formation was ceased if the GSA concentration was less than 1010cm-3 which suggests, based on the measurements, the usage of biofuel to prevent volatile particles in diesel exhaust.

  1. Effects of prenatal exposure to diesel exhaust particles on postnatal development, behavior, genotoxicity and inflammation in mice

    Directory of Open Access Journals (Sweden)

    Vogel Ulla

    2008-03-01

    Full Text Available Abstract Background Results from epidemiological studies indicate that particulate air pollution constitutes a hazard for human health. Recent studies suggest that diesel exhaust possesses endocrine activity and therefore may affect reproductive outcome. This study in mice aimed to investigate whether exposure to diesel exhaust particles (DEP; NIST 2975 would affect gestation, postnatal development, activity, learning and memory, and biomarkers of transplacental toxicity. Pregnant mice (C57BL/6; BomTac were exposed to 19 mg/m3 DEP (~1·106 particles/cm3; mass median diameter ≅ 240 nm on gestational days 9–19, for 1 h/day. Results Gestational parameters were similar in control and diesel groups. Shortly after birth, body weights of DEP offspring were slightly lower than in controls. This difference increased during lactation, so by weaning the DEP exposed offspring weighed significantly less than the control progeny. Only slight effects of exposure were observed on cognitive function in female DEP offspring and on biomarkers of exposure to particles or genotoxic substances. Conclusion In utero exposure to DEP decreased weight gain during lactation. Cognitive function and levels of biomarkers of exposure to particles or to genotoxic substances were generally similar in exposed and control offspring. The particle size and chemical composition of the DEP and differences in exposure methods (fresh, whole exhaust versus aged, resuspended DEP may play a significant role on the biological effects observed in this compared to other studies.

  2. Bohm criterion and plasma particle/power exhaust to and recycling at the wall

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    Xian-Zhu Tang

    2017-08-01

    Full Text Available The plasma particle and power exhaust to the divertor surface drives both particle and power recycling at the surface, which in return constrains the plasma density and temperature at the target and their profile further upstream. Both particle and power exhaust fluxes are mediated by the plasma sheath next to the divertor surface. In particular, the Bohm criterion constrains the ion exit flow speed, which enters directly into the particle flux and the kinetic flow energy component of the ion power flux, and indirectly into the electron power flux through the sheath potential drop. Here we give an overview on how the Bohm speed is set in a general plasma and how it enters power exhaust and power recycling at the divertor surface, and the implication on the correct implementation of sheath boundary conditions in numerical codes. The cases of ideal and non-ideal Bohm speed are distinguished as a result of the physics discussion.

  3. Micro- and Nanostructural Characteristics of Particles Before and After an Exhaust Gas Recirculation System Scrubber

    DEFF Research Database (Denmark)

    Lieke, Kirsten Inga; Rosenørn, Thomas; Pedersen, Jannik

    2013-01-01

    This work provides insight into the morphology and mixing state of submicron particles in diesel exhaust from a ship engine with an exhaust gas recirculation scrubber. Particles from this low-speed ship engine on test bed were collected using a microiner-tial impactor with transmission electron...... microscopy (TEM) grids on two stages. Micro- and nanostructural characteristics of sin-gle particles were studied by TEM. Image analysis was carried out on overview and high-resolution images, revealing influence of the exhaust gas treatment (scrubber) on the particle morphology and mixing state. Soot...... agglomerates were found to be collapsed after scrubber, reflected by their change in fractal dimension (fly) from 1.88 to 2.13. Soot was predominantly found internally mixed with other components, with a higher degree of internal mix-ing observed after scrubber. Soot nanostructural characteristics on the near...

  4. Assessment of exhaust emissions from carbon nanotube production and particle collection by sampling filters.

    Science.gov (United States)

    Tsai, Candace Su-Jung; Hofmann, Mario; Hallock, Marilyn; Ellenbecker, Michael; Kong, Jing

    2015-11-01

    This study performed a workplace evaluation of emission control using available air sampling filters and characterized the emitted particles captured in filters. Characterized particles were contained in the exhaust gas released from carbon nanotube (CNT) synthesis using chemical vapor deposition (CVD). Emitted nanoparticles were collected on grids to be analyzed using transmission electron microscopy (TEM). CNT clusters in the exhaust gas were collected on filters for investigation. Three types of filters, including Nalgene surfactant-free cellulose acetate (SFCA), Pall A/E glass fiber, and Whatman QMA quartz filters, were evaluated as emission control measures, and particles deposited in the filters were characterized using scanning transmission electron microscopy (STEM) to further understand the nature of particles emitted from this CNT production. STEM analysis for collected particles on filters found that particles deposited on filter fibers had a similar morphology on all three filters, that is, hydrophobic agglomerates forming circular beaded clusters on hydrophilic filter fibers on the collecting side of the filter. CNT agglomerates were found trapped underneath the filter surface. The particle agglomerates consisted mostly of elemental carbon regardless of the shapes. Most particles were trapped in filters and no particles were found in the exhaust downstream from A/E and quartz filters, while a few nanometer-sized and submicrometer-sized individual particles and filament agglomerates were found downstream from the SFCA filter. The number concentration of particles with diameters from 5 nm to 20 µm was measured while collecting particles on grids at the exhaust piping. Total number concentration was reduced from an average of 88,500 to 700 particle/cm(3) for the lowest found for all filters used. Overall, the quartz filter showed the most consistent and highest particle reduction control, and exhaust particles containing nanotubes were successfully

  5. Single particle mass spectral signatures from vehicle exhaust particles and the source apportionment of on-line PM2.5 by single particle aerosol mass spectrometry.

    Science.gov (United States)

    Yang, Jian; Ma, Shexia; Gao, Bo; Li, Xiaoying; Zhang, Yanjun; Cai, Jing; Li, Mei; Yao, Ling'ai; Huang, Bo; Zheng, Mei

    2017-09-01

    In order to accurately apportion the many distinct types of individual particles observed, it is necessary to characterize fingerprints of individual particles emitted directly from known sources. In this study, single particle mass spectral signatures from vehicle exhaust particles in a tunnel were performed. These data were used to evaluate particle signatures in a real-world PM2.5 apportionment study. The dominant chemical type originating from average positive and negative mass spectra for vehicle exhaust particles are EC species. Four distinct particle types describe the majority of particles emitted by vehicle exhaust particles in this tunnel. Each particle class is labeled according to the most significant chemical features in both average positive and negative mass spectral signatures, including ECOC, NaK, Metal and PAHs species. A single particle aerosol mass spectrometry (SPAMS) was also employed during the winter of 2013 in Guangzhou to determine both the size and chemical composition of individual atmospheric particles, with vacuum aerodynamic diameter (dva) in the size range of 0.2-2μm. A total of 487,570 particles were chemically analyzed with positive and negative ion mass spectra and a large set of single particle mass spectra was collected and analyzed in order to identify the speciation. According to the typical tracer ions from different source types and classification by the ART-2a algorithm which uses source fingerprints for apportioning ambient particles, the major sources of single particles were simulated. Coal combustion, vehicle exhaust, and secondary ion were the most abundant particle sources, contributing 28.5%, 17.8%, and 18.2%, respectively. The fraction with vehicle exhaust species particles decreased slightly with particle size in the condensation mode particles. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Diesel Exhaust Exposure Assessment Among Tunnel Construction Workers-Correlations Between Nitrogen Dioxide, Respirable Elemental Carbon, and Particle Number.

    Science.gov (United States)

    Hedmer, Maria; Wierzbicka, Aneta; Li, Huiqi; Albin, Maria; Tinnerberg, Håkan; Broberg, Karin

    2017-06-01

    Occupational exposure to diesel exhaust is common due the widespread use of diesel-powered combustion engines. Diesel exhaust is chemically complex and consists of thousands of compounds present as gases and particulate matter. Both nitrogen dioxide (NO2) and elemental carbon (EC) have been used as markers for diesel exhaust exposure. Currently EC is regarded as the best surrogate of diesel exhaust. The objective was to quantify the occupational exposure to diesel exhaust in underground tunnel construction work using a multi-metric approach, and to investigate the correlations between NO2, respirable EC, respirable organic carbon (OC), respirable total carbon (TC), respirable dust (RD), and particle number. Also, the use of NO2 as a proxy for diesel exhaust was evaluated, how much of the variability in the diesel exhaust exposure was attributed to within and between individual factors and if there was a difference between expert and self-administered measurements of NO2. The personal exposure to diesel exhaust was assessed by expert supervised measurements of NO2, EC, OC, TC, RD and particle number in the breathing zones of underground tunnel workers. Stationary sampling of NO2, EC, OC, TC, RD, size-fractioned mass concentration, and particle number were conducted. The personal and stationary measurements were conducted on three occasions simultaneously. The workers measured their exposure by repeated self-administered measurements of NO2. The self-administered measurements were performed twice for each worker with at least one month lag between the samplings. In the simultaneous sampling of diesel exhaust, the geometric mean (GM) concentration of NO2 and respirable EC were 72 µg m-3 (10th-90th percentile 34-140 µg m-3) and 2.6 µg m-3 (10th-90th percentile 1.6-7.3 µg m-3), respectively. The GM for OC and TC was 28 µg m-3 (10th-90th percentile 20-42 µg m-3) and 31 µg m-3 (10th-90th percentile 20-50 µg m-3), respectively. The GM for RD and particle number was

  7. Diesel exhaust particles. Effects of after-treatment, fuel and lubricant

    Energy Technology Data Exchange (ETDEWEB)

    Vaaraslahti, K.

    2006-07-01

    This thesis concentrates on studying diesel particles which are under a great attention due to their health effects. This has pushed the policymakers worldwide to limit the particle emissions of diesel vehicles. Engine manufacturers are developing their products to achieve the emission limits. Exhaust gas after-treatment systems are becoming general. In addition to fuel more attention is going to be paid to lubricant and its effects on emissions. This has also given the focus to present work, which studies the effects of after-treatment systems, fuels and lubricants on diesel particle emissions. The study utilizes regulated particle emissions measurements as a relevant reference. Although, the main focus is studying the particles further for size and number. This is done using two size distribution measurement devices, SMPS and ELPI. Only steady state driving conditions are used as they serve stable conditions for studying the particle formation using different after-treatment systems in combination with different fuels and lubricants. Oxidation catalysts and particle filters were used as after-treatment. The study of fuel effect was limited to study the effect of fuel sulfur level on the particle emission. The lubricants used contained both market general formulations and development formulations. The results showed that at high load conditions only soot particles with some absorbed/condensed volatile material were formed. Neither the fuels nor the lubricants tested had any significant effect on the soot particles. An oxidation catalyst was found to effectively reduce the soluble organic fraction but had only minor or no effect on the soot part. A catalyzed filter was found to effectively reduce the soot. At low load conditions in addition to soot particles, nanoparticles were formed. The used lubricant was found to significantly effect the nanoparticle formation although no correlation between the sulfur level and nanoparticles was found in this case. These

  8. Numerical modelling of the internal mixing by coagulation of black carbon particles in aircraft exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Ohlsson, S.; Stroem, J. [Stockholm Univ. (Sweden). Dept. of Meteorology

    1997-12-31

    When exhaust gases from an aircraft engine mix with ambient air the humidity may reach water saturation and water droplets will form on the available cloud condensation nuclei (CCN). It is still not resolved if the CCN, on which the cloud droplets form, are mainly particles present in the ambient air or particles emitted by the aircraft. It the exhaust from a jet engine the particles are believed to consist mainly of black carbon (BC) and sulfate. The aim is to study, with the help of a numerical model, how a two-component aerosol (i.e. BC and sulfate) in an exhaust trail may be transformed in terms of hygroscopicity by coagulation mixing and how this may depend on the sulfur content in the fuel. (R.P.) 15 refs.

  9. Effect of lubricant sulfur on the morphology and elemental composition of diesel exhaust particles.

    Science.gov (United States)

    Tan, Piqiang; Li, Yuan; Shen, Hanyan

    2017-05-01

    This work investigates the effects of lubricant sulfur contents on the morphology, nanostructure, size distribution and elemental composition of diesel exhaust particle on a light-duty diesel engine. Three kinds of lubricant (LS-oil, MS-oil and HS-oil, all of which have different sulfur contents: 0.182%, 0.583% and 1.06%, respectively) were used in this study. The morphologies and nanostructures of exhaust particles were analyzed using high-resolution transmission electron microscopy (TEM). Size distributions of primary particles were determined through advanced image-processing software. Elemental compositions of exhaust particles were obtained through X-ray energy dispersive spectroscopy (EDS). Results show that as lubricant sulfur contents increase, the macroscopic structure of diesel exhaust particles turn from chain-like to a more complex agglomerate. The inner cores of the core-shell structure belonging to these primary particles change little; the shell thickness decreases, and the spacing of carbon layer gradually descends, and amorphous materials that attached onto outer carbon layer of primary particles increase. Size distributions of primary particles present a unimodal and normal distribution, and higher sulfur contents lead to larger size primary particles. The sulfur content in lubricants directly affects the chemical composition in the particles. The content of C (carbon) decreases as sulfur increases in the lubricants, while the contents of O (oxygen), S (sulfur) and trace elements (including S, Si (silicon), Fe (ferrum), P (phosphorus), Ca (calcium), Zn (zinc), Mg (magnesium), Cl (chlorine) and Ni (nickel)) all increase in particles. Copyright © 2017. Published by Elsevier B.V.

  10. A source-independent empirical correction procedure for the fast mobility and engine exhaust particle sizers

    Science.gov (United States)

    Zimmerman, Naomi; Jeong, Cheol-Heon; Wang, Jonathan M.; Ramos, Manuel; Wallace, James S.; Evans, Greg J.

    2015-01-01

    The TSI Fast Mobility Particle Sizer (FMPS) and Engine Exhaust Particle Sizer (EEPS) provide size distributions for 6-560 nm particles with a time resolution suitable for characterizing transient particle sources; however, the accuracy of these instruments can be source dependent, due to influences of particle morphology. The aim of this study was to develop a source-independent correction protocol for the FMPS and EEPS. The correction protocol consists of: (1) broadening the >80 nm size range of the distribution to account for under-sizing by the FMPS and EEPS; (2) applying an existing correction protocol in the 8-93 nm size range; and (3) dividing each size bin by the ratio of total concentration measured by the FMPS or EEPS and a water-based Condensation Particle Counter (CPC) as a surrogate scaling factor to account for particle morphology. Efficacy of the correction protocol was assessed for three sources: urban ambient air, diluted gasoline direct injection engine exhaust, and diluted diesel engine exhaust. Linear regression against a reference instrument, the Scanning Mobility Particle Sizer (SMPS), before and after applying the correction protocol demonstrated that the correction ensured agreement within 20%.

  11. Toxicity of aged gasoline exhaust particles to normal and diseased airway epithelia.

    Science.gov (United States)

    Künzi, Lisa; Krapf, Manuel; Daher, Nancy; Dommen, Josef; Jeannet, Natalie; Schneider, Sarah; Platt, Stephen; Slowik, Jay G; Baumlin, Nathalie; Salathe, Matthias; Prévôt, André S H; Kalberer, Markus; Strähl, Christof; Dümbgen, Lutz; Sioutas, Constantinos; Baltensperger, Urs; Geiser, Marianne

    2015-06-29

    Particulate matter (PM) pollution is a leading cause of premature death, particularly in those with pre-existing lung disease. A causative link between particle properties and adverse health effects remains unestablished mainly due to complex and variable physico-chemical PM parameters. Controlled laboratory experiments are required. Generating atmospherically realistic aerosols and performing cell-exposure studies at relevant particle-doses are challenging. Here we examine gasoline-exhaust particle toxicity from a Euro-5 passenger car in a uniquely realistic exposure scenario, combining a smog chamber simulating atmospheric ageing, an aerosol enrichment system varying particle number concentration independent of particle chemistry, and an aerosol deposition chamber physiologically delivering particles on air-liquid interface (ALI) cultures reproducing normal and susceptible health status. Gasoline-exhaust is an important PM source with largely unknown health effects. We investigated acute responses of fully-differentiated normal, distressed (antibiotics-treated) normal, and cystic fibrosis human bronchial epithelia (HBE), and a proliferating, single-cell type bronchial epithelial cell-line (BEAS-2B). We show that a single, short-term exposure to realistic doses of atmospherically-aged gasoline-exhaust particles impairs epithelial key-defence mechanisms, rendering it more vulnerable to subsequent hazards. We establish dose-response curves at realistic particle-concentration levels. Significant differences between cell models suggest the use of fully-differentiated HBE is most appropriate in future toxicity studies.

  12. Sedimentation of active particles

    OpenAIRE

    Vachier, Jérémy; Marco G. Mazza

    2017-01-01

    Active particles convert energy from chemical, biochemical, or other processes into motion. Their collective motion has attracted enormous interest on account of the technological applications of artificial and biological particles. By combining theoretical arguments, and molecular dynamics simulations we explore the collective behavior of active particles under a gravity field in three dimensions. Dilute systems exhibit sedimentation, which we study with two approaches. Firstly, we solve ana...

  13. An investigation into the effect of a ceramic particle trap on the chemical mutagens in diesel exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Bagley, S.T.; Dorie, L.D.; Leddy, D.G.; Johnson, J.H. (Michigan Technological Univ., Houghton (USA))

    1987-01-01

    Diesel exhaust particles and vapor phase samples were collected from the diluted (15:1) exhaust of a 10.4 L displacement medium-duty engine (Caterpillar 3208), operated under EPA steady-state cycle Modes 4 and 5 conditions for load (50 and 75 percent, respectively) and speed (1680 rpm). Baseline (uncontrolled) emissions were compared to the exhaust modified by the use of an uncatalyzed monolithic ceramic trap (Corning). The Salmonella/microsome mutagenicity bioassay (Ames Test) was used to direct the course of chemical analyses. Total particulate matter (TPM), soluble organic fraction (SOF) (from TPM), sulfate fraction (SO4) (from TPM), and solid fraction (SOL) (from particle) were determined from dilute exhaust particles collected on 47 mm Teflon-coated woven glass fiber filters. Coincidentally, particles were collected on 508 x 508 mm Teflon-coated non-woven glass fiber filters, and vapor-phase samples were collected on XAD-2 resin. The SOF and VOC for chemical and biological characterization were obtained by Soxhlet extraction of samples with dichloromethane (DCM). Hydrocarbon mass balances were developed to evaluate the efficiency of the sampling system. Use of the ceramic traps caused no change in engine total hydrocarbon (HC) levels at Mode 4 but decreases in TPM, SOF, and NO2 were noted. In terms of HC emissions only, the percentage of SOF was significantly reduced, but the percentage of VOC was unchanged. For Mode 5, the engine HC levels were significantly reduced but the proportions of HC components, i.e. the percentage of SOF and the percentage of VOC, did not change significantly. Engine emission levels of TPM, SOF, and nitrogen dioxide were also significantly reduced at Mode 5. At both Modes 4 and 5, use of the ceramic particle traps caused an increase in the direct-acting (TA98) mutagenicity of the SOF and a decrease in the activity of the VOC.

  14. Model studies of volatile diesel exhaust particle formation: are organic vapours involved in nucleation and growth?

    Science.gov (United States)

    Pirjola, L.; Karl, M.; Rönkkö, T.; Arnold, F.

    2015-09-01

    A high concentration of volatile nucleation mode particles (NUP) formed in the atmosphere when the exhaust cools and dilutes has hazardous health effects and it impairs the visibility in urban areas. Nucleation mechanisms in diesel exhaust are only poorly understood. We performed model studies using two sectional aerosol dynamics process models AEROFOR and MAFOR on the formation of particles in the exhaust of a diesel engine, equipped with an oxidative after-treatment system and running with low fuel sulfur content (FSC) fuel, under laboratory sampling conditions where the dilution system mimics real-world conditions. Different nucleation mechanisms were tested. Based on the measured gaseous sulfuric acid (GSA) and non-volatile core and soot particle number concentrations of the raw exhaust, the model simulations showed that the best agreement between model predictions and measurements in terms of particle number size distribution was obtained by barrier-free heteromolecular homogeneous nucleation between the GSA and a semi-volatile organic vapour combined with the homogeneous nucleation of GSA alone. Major growth of the particles was predicted to occur due to the similar organic vapour at concentrations of (1-2) × 1012 cm-3. The pre-existing core and soot mode concentrations had an opposite trend on the NUP formation, and the maximum NUP formation was predicted if a diesel particle filter (DPF) was used. On the other hand, the model predicted that the NUP formation ceased if the GSA concentration in the raw exhaust was less than 1010 cm-3, which was the case when biofuel was used.

  15. Automobile diesel exhaust particles induce lipid droplet formation in macrophages in vitro

    DEFF Research Database (Denmark)

    Cao, Yi; Jantzen, Kim; Gouveia, Ana Cecilia Damiao

    2015-01-01

    Exposure to diesel exhaust particles (DEP) has been associated with adverse cardiopulmonary health effects, which may be related to dysregulation of lipid metabolism and formation of macrophage foam cells. In this study, THP-1 derived macrophages were exposed to an automobile generated DEP (A...... that exposure to A-DEP may induce formation of lipid droplets in macrophages in vitro possibly via lysosomal dysfunction....

  16. SAMPLE CHARACTERIZATION OF AUTOMOBILE AND FORKLIFT DIESEL EXHAUST PARTICLES AND COMPARATIVE PULMONARY TOXICITY IN MICE

    Science.gov (United States)

    AbstractTwo samples of diesel exhaust particles (DEP) predominate in DEP health effects research: an automobile-source DEP (A-DEP) sample and the National Institute of Standards Technology (NIST) standard reference material (SRM 2975) generated from a forklift engine...

  17. BIOASSAY-DIRECTED FRACTIONAL AND SALMONELLA MUTAGENICITY OF AUTOMOBILE AND FORKLIFT DIESEL EXHAUST PARTICLES

    Science.gov (United States)

    Abstract Many pulmonary toxicity studies of diesel exhaust particles (DEP) have used anautomobile-generated sample (A-DEP) whose mutagenicity has not been reported. In contrast,rnany inutagenicity studies of DEP have used a forklift-generated sample (SRM ...

  18. Simulation of the evolution of particle size distributions in a vehicle exhaust plume with unconfined dilution by ambient air.

    Science.gov (United States)

    Jiang, Pengzhi; Lignell, David O; Kelly, Kerry E; Lighty, JoAnn S; Sarofim, Adel F; Montgomery, Christopher J

    2005-04-01

    Over the past several years, numerous studies have linked ambient concentrations of particulate matter (PM) to adverse health effects, and more recent studies have identified PM size and surface area as important factors in determining the health effects of PM. This study contributes to a better understanding of the evolution of particle size distributions in exhaust plumes with unconfined dilution by ambient air. It combines computational fluid dynamics (CFD) with an aerosol dynamics model to examine the effects of different streamlines in an exhaust plume, ambient particle size distributions, and vehicle and wind speed on the particle size distribution in an exhaust plume. CFD was used to calculate the flow field and gas mixing for unconfined dilution of a vehicle exhaust plume, and the calculated dilution ratios were then used as input to the aerosol dynamics simulation. The results of the study show that vehicle speed affected the particle size distribution of an exhaust plume because increasing vehicle speed caused more rapid dilution and inhibited coagulation. Ambient particle size distributions had an effect on the smaller sized particles (approximately 10 nm range under some conditions) and larger sized particles (>2 microm) of the particle size distribution. The ambient air particle size distribution affects the larger sizes of the exhaust plume because vehicle exhaust typically contains few particles larger than 2 microm. Finally, the location of a streamline in the exhaust plume had little effect on the particle size distribution; the particle size distribution along any streamline at a distance x differed by less than 5% from the particle size distributions along any other streamline at distance x.

  19. Mechanisms of GM-CSF increase by diesel exhaust particles in human airway epithelial cells.

    Science.gov (United States)

    Boland, S; Bonvallot, V; Fournier, T; Baeza-Squiban, A; Aubier, M; Marano, F

    2000-01-01

    We have previously shown that exposure to diesel exhaust particles (DEPs) stimulates human airway epithelial cells to secrete the inflammatory cytokines interleukin-8, interleukin-1beta, and granulocyte-macrophage colony-stimulating factor (GM-CSF) involved in allergic diseases. In the present paper, we studied the mechanisms underlying the increase in GM-CSF release elicited by DEPs using the human bronchial epithelial cell line 16HBE14o-. RT-PCR analysis has shown an increase in GM-CSF mRNA levels after DEP treatments. Comparison of the effects of DEPs, extracted DEPs, or extracts of DEPs has shown that the increase in GM-CSF release is mainly due to the adsorbed organic compounds and not to the metals present on the DEP surface because the metal chelator desferrioxamine had no inhibitory effect. Furthermore, radical scavengers inhibited the DEP-induced GM-CSF release, showing involvement of reactive oxygen species in this response. Moreover genistein, a tyrosine kinase inhibitor, abrogated the effects of DEPs on GM-CSF release, whereas protein kinase (PK) C, PKA, cyclooxygenase, or lipoxygenase inhibitors had no effect. PD-98059, an inhibitor of mitogen-activated protein kinase, diminished the effects of DEPs, whereas SB-203580, an inhibitor of p38 mitogen-activated protein kinase, had a lower effect, and DEPs did actually increase the active, phosphorylated form of the extracellular signal-regulated kinase as shown by Western blotting. In addition, cytochalasin D, which inhibits the phagocytosis of DEPs, reduced the increase in GM-CSF release after DEP treatment. Together, these data suggest that the increase in GM-CSF release is mainly due to the adsorbed organic compounds and that the effect of native DEPs requires endocytosis of the particles. Reactive oxygen species and tyrosine kinase(s) may be involved in the DEP-triggered signaling of the GM-CSF response.

  20. Bioassay-directed fractionation and salmonella mutagenicity of automobile and forklift diesel exhaust particles.

    Science.gov (United States)

    DeMarini, David M; Brooks, Lance R; Warren, Sarah H; Kobayashi, Takahiro; Gilmour, M Ian; Singh, Pramila

    2004-06-01

    Many pulmonary toxicity studies of diesel exhaust particles (DEPs) have used an automobile-generated sample (A-DEPs) whose mutagenicity has not been reported. In contrast, many mutagenicity studies of DEPs have used a forklift-generated sample (SRM 2975) that has been evaluated in only a few pulmonary toxicity studies. Therefore, we evaluated the mutagenicity of both DEPs in Salmonella coupled to a bioassay-directed fractionation. The percentage of extractable organic material (EOM) was 26.3% for A-DEPs and 2% for SRM 2975. Most of the A-EOM (~55%) eluted in the hexane fraction, reflecting the presence of alkanes and alkenes, typical of uncombusted fuel. In contrast, most of the SRM 2975 EOM (~58%) eluted in the polar methanol fraction, indicative of oxygenated and/or nitrated organics derived from combustion. Most of the direct-acting, base-substitution activity of the A-EOM eluted in the hexane/dichloromethane (DCM) fraction, but this activity eluted in the polar methanol fraction for the SRM 2975 EOM. The direct-acting frameshift mutagenicity eluted across fractions of A-EOM, whereas > 80% eluted only in the DCM fraction of SRM 2975 EOM. The A-DEPs were more mutagenic than SRM 2975 per mass of particle, having 227 times more polycyclic aromatic hydrocarbon-type and 8-45 more nitroarene-type mutagenic activity. These differences were associated with the different conditions under which the two DEP samples were generated and collected. A comprehensive understanding of the mechanisms responsible for the health effects of DEPs requires the evaluation of DEP standards for a variety of end points, and our results highlight the need for multidisciplinary studies on a variety of representative samples of DEPs.

  1. The role of sulfur emission in volatile particle formation in jet aircraft exhaust plumes

    Science.gov (United States)

    Kärcher, B.; Fahey, D. W.

    Recent in-situ emission measurements of the Concorde in the lower stratosphere point to a surprisingly efficient conversion of fuel sulfur to H2SO4 in the exhaust plume. By means of a comprehensive model, the formation and evolution of aerosol particles and precursors are calculated in the diluting aircraft wake. The results provide strong evidence that high levels of SO3 present in the nascent plume are required to explain the observations of large numbers of nanometer-sized aerosols. Limiting particle formation at emission to keep potential chemical effects on stratospheric ozone small will require control of the sulfur oxidation kinetics during fuel combustion. The similarities between super- and subsonic exhaust plumes suggest that the presence of SO3 in the latter will also be a key limiting factor in new aerosol production.

  2. Tuning the structure of platinum particles on ceria in situ for enhancing the catalytic performance of exhaust gas catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gaenzler, Andreas M.; Casapu, Maria; Grunwaldt, Jan-Dierk [Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Vernoux, Philippe; Loridant, Stephane; Cadete Santos Aires, Francisco J. [Institut de Recherches sur la Catalyse et l' Environnement de Lyon, UMR 5256, CNRS, Universite Claude Bernard Lyon 1, Universite de Lyon, Villeurbanne (France); Epicier, Thierry [Materiaux, Ingenierie et Science, UMR 5510, CNRS, INSA de Lyon, Universite de Lyon, Villeurbanne (France); Betz, Benjamin [Umicore AG and Co. KG, Hanau (Germany); Ernst-Berl Institut, Technische Universitaet Darmstadt (Germany); Hoyer, Ruediger [Umicore AG and Co. KG, Hanau (Germany)

    2017-10-09

    A dynamic structural behavior of Pt nanoparticles on the ceria surface under reducing/oxidizing conditions was found at moderate temperatures (<500 C) and exploited to enhance the catalytic activity of Pt/CeO{sub 2}-based exhaust gas catalysts. Redispersion of platinum in an oxidizing atmosphere already occurred at 400 C. A protocol with reducing pulses at 250-400 C was applied in a subsequent step for controlled Pt-particle formation. Operando X-ray absorption spectroscopy unraveled the different extent of reduction and sintering of Pt particles: The choice of the reductant allowed the tuning of the reduction degree/particle size and thus the catalytic activity (CO>H{sub 2}>C{sub 3}H{sub 6}). This dynamic nature of Pt on ceria at such low temperatures (250-500 C) was additionally confirmed by in situ environmental transmission electron microscopy. A general concept is proposed to adjust the noble metal dispersion (size, structure), for example, during operation of an exhaust gas catalyst. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Diesel exhaust particle-induced airway responses are augmented in obese rats.

    Science.gov (United States)

    Moon, Kuk-Young; Park, Moo-Kyun; Leikauf, George D; Park, Choon-Sik; Jang, An-Soo

    2014-01-01

    Air pollutants and obesity are important factors that contribute to asthma. The aim of this study was to assess the airway responsiveness and inflammation in Otsuka-Long Evans Tokushima Fatty (OLETF) obese rats and Long Evans Tokushima-Otsuka (LETO) nonobese rats exposed to diesel exhaust particles (DEPs). Otsuka Long Evans Tokushima fatty rats and LETO rats were exposed intranasally to DEP and then challenged with aerosolized DEP on days 6 to 8. Body plethysmography, bronchoalveolar lavage (BAL), and histology were performed. Enhanced pause (Penh) was measured as an indicator of airway resistance on day 9 and samples were collected on day 10. After exposure to DEP, the OLETF group exhibited a greater increase in Penh compared to that in the LETO group. Moreover, the BAL fluid in mice showed an increase in the total and differential cell counts in the DEP-exposed OLETF group compared to that in the DEP-exposed LETO group. Histological assessment of lung tissue from each group revealed that the DEP-exposed OLETF group tended to have increased inflammatory cell infiltrations in the prebronchial area. Increased peroxisome proliferator-activated receptor γ, coactivator 1β messenger RNA was observed in the lungs of obese rats compared to that in nonobese rats following DEP exposure. These data indicate that the DEP-exposed OLETF group had increased airway responses and inflammation compared to the DEP-exposed LETO group, indicating that diesel particulates and obesity may be co-contributors to asthma.

  4. Effects of prenatal exposure to diesel exhaust particles on postnatal development, behavior, genotoxicity and inflammation in mice

    DEFF Research Database (Denmark)

    Hougaard, K. S.; Jensen, K. A.; Nordly, P.

    2008-01-01

    Background: Results from epidemiological studies indicate that particulate air pollution constitutes a hazard for human health. Recent studies suggest that diesel exhaust possesses endocrine activity and therefore may affect reproductive outcome. This study in mice aimed to investigate whether...... significantly less than the control progeny. Only slight effects of exposure were observed on cognitive function in female DEP offspring and on biomarkers of exposure to particles or genotoxic substances. Conclusion: In utero exposure to DEP decreased weight gain during lactation. Cognitive function and levels...... effects observed in this compared to other studies....

  5. Capture Efficiency of Cooking-Related Fine and Ultrafine Particles by Residential Exhaust Hoods

    Energy Technology Data Exchange (ETDEWEB)

    Lunden, Melissa M.; Delp, William W.

    2014-06-05

    Effective exhaust hoods can mitigate the indoor air quality impacts of pollutant emissions from residential cooking. This study reports capture efficiencies (CE) measured for cooking generated particles for scripted cooking procedures in a 121-m3 chamber with kitchenette. CEs also were measured for burner produced CO2 during cooking and separately for pots and pans containing water. The study used four exhaust hoods previously tested by Delp and Singer (Environ. Sci. Technol., 2012, 46, 6167-6173). For pan-frying a hamburger over medium heat on the back burner, CEs for particles were similar to those for burner produced CO2 and mostly above 80percent. For stir-frying green beans in a wok (high heat, front burner), CEs for burner CO2 during cooking varied by hood and airflow: CEs were 34-38percent for low (51?68 L s-1) and 54?72percent for high (109?138 L s-1) settings. CEs for 0.3?2.0 ?m particles during front burner stir-frying were 3?11percent on low and 16?70percent on high settings. Results indicate that CEs measured for burner CO2 are not predictive of CEs of cooking-generated particles under all conditions, but they may be suitable to identify devices with CEs above 80percent both for burner combustion products and for cooking-related particles.

  6. The Effect of Pt Particle Size on the Oxidation of CO, C3H6, and NO Over Pt/Al2O3 for Diesel Exhaust Aftertreatment

    DEFF Research Database (Denmark)

    Hansen, Thomas Klint; Høj, Martin; Hansen, Brian Brun

    2017-01-01

    Platinum-based oxidation catalysts applied for diesel exhaust aftertreatment constitute a significant part of system costs. Effective utilization of platinum is therefore relevant to reduce costs while retaining performance. To this end, the influence of Pt particle size on catalytic activity...

  7. Frequency band analysis of muscle activation during cycling to exhaustion

    Directory of Open Access Journals (Sweden)

    Fernando Diefenthaeler

    2012-04-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n3p243 Lower limb muscles activation was assessed during cycling to exhaustion using frequency band analysis. Nine cyclists were evaluated in two days. On the first day, cyclists performed a maximal incremental cycling exercise to measure peak power output, which was used on the second day to define the workload for a constant load time to exhaustion cycling exercise (maximal aerobic power output from day 1. Muscle activation of vastus lateralis (VL, long head of biceps femoris (BF, lateral head of gastrocnemius (GL, and tibialis anterior (TA from the right lower limb was recorded during the time to exhaustion cycling exercise. A series of nine band-pass Butterworth digital filters was used to analyze muscle activity amplitude for each band. The overall amplitude of activation and the high and low frequency components were defined to assess the magnitude of fatigue effects on muscle activity via effect sizes. The profile of the overall muscle activation during the test was analyzed using a second order polynomial, and the variability of the overall bands was analyzed by the coefficient of variation for each muscle in each instant of the test. Substantial reduction in the high frequency components of VL and BF activation was observed. The overall and low frequency bands presented trivial to small changes for all muscles. High relationship between the second order polynomial fitting and muscle activity was found (R2 > 0.89 for all muscles. High variability (~25% was found for muscle activation at the four instants of the fatigue test. Changes in the spectral properties of the EMG signal were only substantial when extreme changes in fatigue state were induced.

  8. Chemical characterization of freshly emitted particulate matter from aircraft exhaust using single particle mass spectrometry

    Science.gov (United States)

    Abegglen, Manuel; Brem, B. T.; Ellenrieder, M.; Durdina, L.; Rindlisbacher, T.; Wang, J.; Lohmann, U.; Sierau, B.

    2016-06-01

    Non-volatile aircraft engine emissions are an important anthropogenic source of soot particles in the upper troposphere and in the vicinity of airports. They influence climate and contribute to global warming. In addition, they impact air quality and thus human health and the environment. The chemical composition of non-volatile particulate matter emission from aircraft engines was investigated using single particle time-of-flight mass spectrometry. The exhaust from three different aircraft engines was sampled and analyzed. The soot particulate matter was sampled directly behind the turbine in a test cell at Zurich Airport. Single particle analyses will focus on metallic compounds. The particles analyzed herein represent a subset of the emissions composed of the largest particles with a mobility diameter >100 nm due to instrumental restrictions. A vast majority of the analyzed particles was shown to contain elemental carbon, and depending on the engine and the applied thrust the elemental carbon to total carbon ratio ranged from 83% to 99%. The detected metallic compounds were all internally mixed with the soot particles. The most abundant metals in the exhaust were Cr, Fe, Mo, Na, Ca and Al; V, Ba, Co, Cu, Ni, Pb, Mg, Mn, Si, Ti and Zr were also detected. We further investigated potential sources of the ATOFMS-detected metallic compounds using Inductively Coupled Plasma Mass Spectrometry. The potential sources considered were kerosene, engine lubrication oil and abrasion from engine wearing components. An unambiguous source apportionment was not possible because most metallic compounds were detected in several of the analyzed sources.

  9. DNA damage in rats after a single oral exposure to diesel exhaust particles

    DEFF Research Database (Denmark)

    Danielsen, Pernille Høgh; Risom, Lotte; Wallin, Håkan

    2008-01-01

    The gastrointestinal route of exposure to particulate matter is important because particles are ingested via contaminated foods and inhaled particles are swallowed when removed from the airways by the mucociliary clearance system. We investigated the effect of an intragastric administration by oral...... gavage of diesel exhaust particles (DEP) in terms of DNA damage, oxidative stress and DNA repair in colon epithelial cells, liver, and lung of rats. Eight rats per group were exposed to Standard Reference Material 2975 at 0.064 or 0.64 mg/kg bodyweight for 6 and 24 h. Increased levels of 8-oxo-7......,8-dihydro-2'-deoxyguanosine lesions were observed at the highest dose after 6 and 24 h in all three organs. 8-Oxo-7,8-dihydro-2'-deoxyguanosine is repaired by oxoguanine DNA glycosylase 1 (OGG1); upregulation of this repair system was observed as elevated pulmonary OGG1 mRNA levels after 24 h at both doses...

  10. Effect of 3-D magnetic fields on neutral particle fueling and exhaust in MAST

    Science.gov (United States)

    Flesch, Kurt; Kremeyer, Thierry; Waters, Ian; Schmitz, Oliver; Kirk, Andrew; Harrison, James

    2017-10-01

    The application of resonant magnetic perturbations (RMPs) is used to suppress edge localized modes but causes in many cases a density pump-out. At MAST, this particle pump out was found to be connected to an amplifying MHD plasma response. An analysis is presented on past MAST discharges to understand the effect of these RMPs on the neutral household and on changes in neutral fueling and exhaust during the pump out. A global, 0-D particle balance model was used to study the neutral dynamics and plasma confinement during shots with and without RMP application. Using the D α emission measured by filterscopes and a calibrated 1-D CCD camera, as well as S/XB coefficients determined by the edge plasma parameters, globally averaged ion confinement times were calculated. In L-mode, discharges with RMPs that caused an MHD response had a 15-20% decrease in confinement time but an increase in total recycling flux. The application of RMPs in H-mode caused either a decrease or no change in confinement, like those in L-mode, depending on the configuration of the RMPs and plasma response. A spectroscopically assisted Penning gauge is being prepared for the next campaign at MAST-U to extend this particle balance to study impurity exhaust with RMPs. This work was funded in part by the U.S. DoE under Grant DE-SC0012315.

  11. Metal particle emissions in the exhaust stream of diesel engines: an electron microscope study.

    Science.gov (United States)

    Liati, Anthi; Schreiber, Daniel; Dimopoulos Eggenschwiler, Panayotis; Arroyo Rojas Dasilva, Yadira

    2013-12-17

    Scanning electron microscopy and transmission electron microscopy were applied to investigate the morphology, mode of occurrence and chemical composition of metal particles (diesel ash) in the exhaust stream of a small truck outfitted with a typical after-treatment system (a diesel oxidation catalyst (DOC) and a downstream diesel particulate filter (DPF)). Ash consists of Ca-Zn-P-Mg-S-Na-Al-K-phases (lube-oil related), Fe, Cr, Ni, Sn, Pb, Sn (engine wear), and Pd (DOC coating). Soot agglomerates of variable sizes (1-5 μm, exceptionally 13 μm), rarely engine wear and escape into the atmosphere.

  12. Effect of short-term exposure to diesel exhaust particles and carboxylic acids on mitochondrial membrane disruption in airway epithelial cells

    Science.gov (United States)

    Rationale: Diesel exhaust has been shown to induce adverse pulmonary health effects; however, the underlying mechanisms for these effects are still unclear. Previous studies have imlplicated mitochondrial dysfunction in the toxicity of diesel exhaust particles (DEP). DEP contain...

  13. Study on Individual PAHs Content in Ultrafine Particles from Solid Fractions of Diesel and Biodiesel Exhaust Fumes

    Directory of Open Access Journals (Sweden)

    Małgorzata Szewczyńska

    2013-01-01

    Full Text Available In order to characterize PAHs emissions of diesel engine fuelled with diesel and its blend (B20, B40. In the particle phase, PAHs in engine exhausts were collected by fiberglass filters using Electrical Low Pressure Impactor (ELPI and then determined by a high performance liquid chromatography with a fluorimetric detector (HPLC-FL. The main content in exhaust gases from diesel engine, regardless the type of applied fuel, is constituted by the particles fraction of diameter <0.25 μm. Particles sized <0.25 μm constituted on average approximately 68% of particles in diesel exhaust gases and approx. 50% of particles emitted by biodiesel B20 and B40. When the B100 bioester additive was applied, the total emission of particles was reduced thus the volume of toxic substances adsorbed on them was lower. The analysis of chemical composition of <0.25 μm exhaust gas fraction showed that there were mainly 3- and 4-ring aromatic hydrocarbons in the exhaust gas of diesel fuel while in B40 single PAHs with the number of rings of 4 and 5 were detected. An application of ELPI permitted a further separation of <0.25 μm particle’s fraction and a real-time determination of interalia number, mass, and surface concentrations.

  14. [Polycyclic aromatic hydrocarbons and soluble organic fraction in fine particles from solid fraction of biodiesel exhaust fumes].

    Science.gov (United States)

    Szewczyńska, Małgorzata; Pośniak, Małgorzata

    2012-01-01

    This paper presents the results of investigations into the distribution of fine particles in the biodiesel exhaust fumes (bio-DEP), as well as into the content of polycyclic aromatic hydrocarbons (PAHs) and soluble organic fraction (SOF) in the study fractions. Samples of biodiesel B20 and B40 exhaust combustion fumes were generated at the model station composed of a diesel engine from Diesel TDI 2007 Volkswagen. Sioutas personal cascade impactor (SPCI) with Teflon filters and low-pressure impactor ELIPI (Dekati Low Pressure Impactor) were used for sampling diesel exhaust fine particles. The analysis of PAHs adsorbed on particulate fractions was performed by high performance liquid chromatography with fluorescence detection (HPLC/FL). For the determination of dry residue soluble organic fraction of biodiesel exhaust particles the gravimetric method was used. The combustion exhaust fumes of 100% ON contained mainly naphthalene, acenaphthalene, fluorene, phenanthrene, fluoranthene, pyrene, benzo(a)anthracene and chrysene, whilst the exhaust of B40-single PAHs of 4 and 5 rings, such as chrysene, benzo(k)fluoranthene, dibenzo (ah)anthracene and benzo(ghi)perylene. The total content of PAHs in diesel exhaust particles averaged 910 ng/m3 for 100% ON and 340 ng/m3 for B40. The concentrations of benzo(a)antarcene were at the levels of 310 ng/m3 (100% ON) and 90 ng/m3 (B40). The investigations indicated that a fraction < 025 microm represents the main component of diesel exhaust particles, regardless of the used fuel. Bioester B 100 commonly added to diesel fuel (ON) causes a reduction of the total particulates emission and thus reduces the amount of toxic substances adsorbed on their surface.

  15. An investigation into the effect of a ceramic particle trap on the chemical mutagens in diesel exhaust.

    Science.gov (United States)

    Bagley, S T; Dorie, L D; Leddy, D G; Johnson, J H

    1987-01-01

    Diesel exhaust particles and vapor phase samples were collected from the diluted (15:1) exhaust of a 10.4 L displacement medium-duty engine (Caterpillar 3208), operated under EPA steady-state cycle Modes 4 and 5 conditions for load (50 and 75 percent, respectively) and speed (1680 rpm). Baseline (uncontrolled) emissions were compared to the exhaust modified by the use of an uncatalyzed monolithic ceramic trap (Corning). The Salmonella/microsome mutagenicity bioassay (Ames Test) was used to direct the course of chemical analyses. Total particulate matter (TPM), soluble organic fraction (SOF) (from TPM), sulfate fraction (SO4) (from TPM), and solid fraction (SOL) (from particle) were determined from dilute exhaust particles collected on 47 mm Teflon-coated woven glass fiber filters. Coincidentally, particles were collected on 508 x 508 mm Teflon-coated non-woven glass fiber filters, and vapor-phase samples were collected on XAD-2 resin. The SOF and VOC for chemical and biological characterization were obtained by Soxhlet extraction of samples with dichloromethane (DCM). Hydrocarbon mass balances were developed to evaluate the efficiency of the sampling system. Use of the ceramic traps caused no change in engine total hydrocarbon (HC) levels at Mode 4 but decreases in TPM, SOF, and NO2 were noted. In terms of HC emissions only, the percentage of SOF was significantly reduced, but the percentage of VOC was unchanged. For Mode 5, the engine HC levels were significantly reduced but the proportions of HC components, i.e. the percentage of SOF and the percentage of VOC, did not change significantly. Engine emission levels of TPM, SOF, and nitrogen dioxide (NO2) were also significantly reduced at Mode 5. At both Modes 4 and 5, use of the ceramic particle traps caused an increase in the direct-acting (TA98) mutagenicity (revertants/microgram) of the SOF and a decrease in the activity of the VOC. The traps caused a 70 percent reduction of TPM at Mode 4 but only a 45 percent

  16. Particle-Bound PAH Emission from the Exhaust of Combustion Chamber

    Science.gov (United States)

    Asgari Lamjiri, M.; Medrano, Y. S.; Guillaume, D. W.; Khachikian, C. S.

    2013-12-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are harmful, semi-volatile organic compounds which are generated due to the incomplete combustion of organic substances. PAHs are of concern as a pollutant because some of these compounds are carcinogenic and mutagenic even at low levels. Most of the PAHs are recalcitrant and persistent in the environment. The PAHs carcinogenic potential can be increased by the adsorption onto small size particles (extracting the particles with dichloromethane followed by analysis via gas chromatography/mass spectrometry (GC/MS). In general, lower molecular weight PAHs emitted from the exhaust of combustion chamber are mostly in gas phase while PAHs of higher molecular weight are adsorbed onto particles. Preliminary results from GC/MS confirm the presence of higher molecular weight PAHs like Benzo[a]pyrene in most of the samples. Better recirculation between air and fuel in higher swirl numbers results in better combustion. In higher swirl numbers, the temperature of the combustion process increases which leads to a more complete combustion. Another result of higher swirl number is a longer residence time which allows the organic substances in the fuel to remain in the reaction longer and also leads to a more complete combustion. The preliminary results from particle analyzer show that the abundance ratio of smaller particles to larger particles increases at higher swirl numbers. For example, at swirl 86, the abundance ratio of 0.3 micron particles to 0.7 micron particles was 400 while at swirl 0, this ratio was 35. Smaller particles have higher specific surface area which allows for more PAH adsorption. The preliminary results show that operating the jet engine at higher swirl numbers can have positive or negative effects on particle-bound PAH emissions. Higher temperature and residence time as well as better mixture of fuel and air can reduce PAH emission while generating more small size particles can increase surface available for PAH

  17. EVALUATION OF DISPERSED PARTICLE CONTENT IN EXHAUST GAS OF DIESEL ENGINE

    Directory of Open Access Journals (Sweden)

    G. M. Kuharonak

    2016-01-01

    Full Text Available Pollution of an atmosphere due to hazardous substances emissions deteriorates ecological environment in the world. Exhaust gases of diesel engines are considered as one of the main environmental pollutants. At the moment it is not possible to determine rate and limits of threshold level of air pollution which do not affect human health. The paper considers current issues pertaining to regulation and control over dispersed particles. The most convenient measuring methods for investigations are those which provide the opportunity to obtain immediate results. However, from the legislative point of view, a gravimetric investigation method is a legitimate one which requires compliance with certain procedures of adjustments and calculations. The method presupposes availability of complicated system for sample dilution and its adjustment must include temperature and kinetic parameters of the measured flow. In order to ensure measuring accuracy and results reproducibility filter loading should be in a regulated range and dilution parameters should be chosen according to not only engine type but also according to its emissions rate. Methods for evaluation of a hot exhaust gas sample is characterized by higher response and the results correlate with indices of combustion efficiency. However, such approach does not account for a number of processes that take place during gas cooling in the environment. Therefore, in this case, measuring results are to be evaluated within certain boundary conditions with respect to the object of investigations. Difficulty in achievement of modern ecologocal standards is substantiated by complicated fractional composition and multiple stage process in formation of hazardous components. The paper presents calculated dependences between particles and smokiness and contains a comparative analysis. Methods for measurement and investigations of dispersed particles have analyzed on the basis of the results obtainesd during engine

  18. Exacerbation of allergic inflammation in mice exposed to diesel exhaust particles prior to viral infection

    Directory of Open Access Journals (Sweden)

    Chason Kelly D

    2009-08-01

    Full Text Available Abstract Background Viral infections and exposure to oxidant air pollutants are two of the most important inducers of asthma exacerbation. Our previous studies have demonstrated that exposure to diesel exhaust increases the susceptibility to influenza virus infections both in epithelial cells in vitro and in mice in vivo. Therefore, we examined whether in the setting of allergic asthma, exposure to oxidant air pollutants enhances the susceptibility to respiratory virus infections, which in turn leads to increased virus-induced exacerbation of asthma. Ovalbumin-sensitized (OVA male C57BL/6 mice were instilled with diesel exhaust particles (DEP or saline and 24 hours later infected with influenza A/PR/8. Animals were sacrificed 24 hours post-infection and analyzed for markers of lung injury, allergic inflammation, and pro-inflammatory cytokine production. Results Exposure to DEP or infection with influenza alone had no significant effects on markers of injury or allergic inflammation. However, OVA-sensitized mice that were exposed to DEP and subsequently infected with influenza showed increased levels of eosinophils in lung lavage and tissue. In addition Th2-type cytokines, such as IL-4 and IL-13, and markers of eosinophil chemotaxis, such as CCL11 and CCR3, were increased in OVA-sensitized mice exposed to DEP prior to infection with influenza. These mice also showed increased levels of IL-1α, but not IL-10, RANTES, and MCP-1 in lung homogenates. Conclusion These data suggest that in the setting of allergic asthma, exposure to diesel exhaust could enhance virus-induced exacerbation of allergic inflammation.

  19. DNA damage in lung after oral exposure to diesel exhaust particles in Big Blue (R) rats

    DEFF Research Database (Denmark)

    Müller, Anne Kirstine; Farombi, E.O.; Møller, P.

    2004-01-01

    . Lung tissue is a target organ for DEP induced cancer following inhalation. Recent studies have provided evidence that the lung is also a target organ for DNA damage and cancer after oral exposure to other complex mixtures of PAHs. The genotoxic effect of oral administration of DEP was investigated......Several chemical mutagens and carcinogens, including polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs, are adsorbed to the surface of diesel exhaust particles (DEP). DEP can induce formation of reactive oxygen species and cause oxidative DNA damage as well as bulky carcinogen DNA adducts......, in terms of markers of DNA damage, mutations and repair, in the lung of Big Blue(R) rats fed a diet with 0, 0.2, 0.8, 2, 8, 20 or 80 mg DEP/kg feed for 21 days. There was no significant increase in the mutation frequency in the cII gene. However, an increase of DNA damage measured as DNA strand breaks...

  20. Emotional exhaustion, absenteeism, and turnover intentions in childcare teachers: examining the impact of physical activity behaviors.

    Science.gov (United States)

    Carson, Russell L; Baumgartner, Jennifer J; Matthews, Russell A; Tsouloupas, Costas N

    2010-09-01

    Drawing on Salmon's (2001) unifying theory of the beneficial effects of physical exercise, we examined physical activity behaviors as an important, but understudied, buffer against experiences of emotional exhaustion, absenteeism, and turnover intentions in 189 childcare teachers. Structural equation modeling revealed that workplace and leisure-time physical activity were negatively related to emotional exhaustion, which in turn, was positively related to teacher migration and attrition intentions. Post-hoc analyses revealed indirect (mediated) effects between physical activity behaviors and teacher turnover intentions via emotional exhaustion. This theoretically driven model fit the data better than an alternative model whereby emotional exhaustion predicts physical activity behaviors.

  1. Structure–activity relationships of Pt/Al2O3 catalysts for CO and NO oxidation at diesel exhaust conditions

    DEFF Research Database (Denmark)

    Boubnov, Alexey; Dahl, Søren; Johnson, Erik

    2012-01-01

    Structure–performance relationships for Pt/Al2O3 catalysts with mean Pt particle sizes of 1, 2, 3, 5 and 10nm are investigated for the catalytic oxidation of CO and NO under lean-burning diesel exhaust conditions. The most active catalysts for CO oxidation exhibit Pt particles of 2–3nm, having...

  2. Mutagenicity of biodiesel or diesel exhaust particles and the effect of engine operating conditions.

    Science.gov (United States)

    Kisin, Elena R; Shi, X C; Keane, Michael J; Bugarski, Aleksandar B; Shvedova, Anna A

    2013-03-01

    Changing the fuel supply from petroleum based ultra-low sulfur diesel (ULSD) to biodiesel and its blends is considered by many to be a viable option for controlling exposures to particulate material (PM). This is critical in the mining industry where approximately 28,000 underground miners are potentially exposed to relatively high concentrations of diesel particulate matter (DPM). This study was conducted to investigate the mutagenic potential of diesel engine emissions (DEE) from neat (B100) and blended (B50) soy-based fatty acid methyl ester (FAME) biodiesel in comparison with ULSD PM using different engine operating conditions and exhaust aftertreatment configurations. The DPM samples were collected for engine equipped with either a standard muffler or a combination of the muffler and diesel oxidation catalytic converter (DOC) that was operated at four different steady-state modes. Bacterial gene mutation activity of DPM was tested on the organic solvent extracts using the Ames Salmonella assay. The results indicate that mutagenic activity of DPM was strongly affected by fuels, engine operating conditions, and exhaust aftertreatment systems. The mutagenicity was increased with the fraction of biodiesel in the fuel. While the mutagenic activity was observed in B50 and B100 samples collected from both light-and heavy-load operating conditions, the ULSD samples were mutagenic only at light-load conditions. The presence of DOC in the exhaust system resulted in the decreased mutagenicity when engine was fueled with B100 and B50 and operated at light-load conditions. This was not the case when engine was fueled with ULSD. Heavy-load operating condition in the presence of DOC resulted in a decrease of mutagenicity only when engine was fueled with B50, but not B100 or ULSD. Therefore, the results indicate that DPM from neat or blended biodiesel has a higher mutagenic potency than that one of ULSD. Further research is needed to investigate the health effect of biodiesel

  3. B-cell exhaustion in HIV infection: the role of immune activation.

    Science.gov (United States)

    Moir, Susan; Fauci, Anthony S

    2014-09-01

    To discuss a component of the pathogenic mechanisms of HIV infection in the context of phenotypic and functional alterations in B cells that are due to persistent viral replication leading to aberrant immune activation and cellular exhaustion. We explore how B-cell exhaustion arises during persistent viremia and how it compares with T-cell exhaustion and similar B-cell alterations in other diseases. HIV-associated B-cell exhaustion was first described in 2008, soon after the demonstration of persistent virus-induced T-cell exhaustion, as well as the identification of a subset B cells in tonsil tissues with immunoregulatory features similar to those observed in T-cell exhaustion. Our understanding of B-cell exhaustion has since expanded in two important areas: the role of inhibitory receptors in the unresponsiveness of exhausted B cells and the increasing evidence that similar B cells are found in other diseases that are associated with aberrant immune activation and inflammation. The phenomenon of B-cell exhaustion is now well established in HIV infection and other diseases characterized by immune activation. Over the coming years, it will be important to understand how cellular exhaustion affects the capacity of the immune system to respond to persisting primary pathogens, as well as to other microbial antigens, whether encountered as secondary infections or following immunization.

  4. Comparison of primary and secondary particle formation from natural gas engine exhaust and of their volatility characteristics

    Science.gov (United States)

    Alanen, Jenni; Simonen, Pauli; Saarikoski, Sanna; Timonen, Hilkka; Kangasniemi, Oskari; Saukko, Erkka; Hillamo, Risto; Lehtoranta, Kati; Murtonen, Timo; Vesala, Hannu; Keskinen, Jorma; Rönkkö, Topi

    2017-07-01

    Natural gas usage in the traffic and energy production sectors is a growing trend worldwide; thus, an assessment of its effects on air quality, human health and climate is required. Engine exhaust is a source of primary particulate emissions and secondary aerosol precursors, which both contribute to air quality and can cause adverse health effects. Technologies, such as cleaner engines or fuels, that produce less primary and secondary aerosols could potentially significantly decrease atmospheric particle concentrations and their adverse effects. In this study, we used a potential aerosol mass (PAM) chamber to investigate the secondary aerosol formation potential of natural gas engine exhaust. The PAM chamber was used with a constant UV-light voltage, which resulted in relatively long equivalent atmospheric ages of 11 days at most. The studied retro-fitted natural gas engine exhaust was observed to form secondary aerosol. The mass of the total aged particles, i.e., particle mass measured downstream of the PAM chamber, was 6-268 times as high as the mass of the emitted primary exhaust particles. The secondary organic aerosol (SOA) formation potential was measured to be 9-20 mg kgfuel-1. The total aged particles mainly consisted of organic matter, nitrate, sulfate and ammonium, with the fractions depending on exhaust after-treatment and the engine parameters used. Also, the volatility, composition and concentration of the total aged particles were found to depend on the engine operating mode, catalyst temperature and catalyst type. For example, a high catalyst temperature promoted the formation of sulfate particles, whereas a low catalyst temperature promoted nitrate formation. However, in particular, the concentration of nitrate needed a long time to stabilize - more than half an hour - which complicated the conclusions but also indicates the sensitivity of nitrate measurements on experimental parameters such as emission source and system temperatures. Sulfate was

  5. Comparison of primary and secondary particle formation from natural gas engine exhaust and of their volatility characteristics

    Directory of Open Access Journals (Sweden)

    J. Alanen

    2017-07-01

    Full Text Available Natural gas usage in the traffic and energy production sectors is a growing trend worldwide; thus, an assessment of its effects on air quality, human health and climate is required. Engine exhaust is a source of primary particulate emissions and secondary aerosol precursors, which both contribute to air quality and can cause adverse health effects. Technologies, such as cleaner engines or fuels, that produce less primary and secondary aerosols could potentially significantly decrease atmospheric particle concentrations and their adverse effects. In this study, we used a potential aerosol mass (PAM chamber to investigate the secondary aerosol formation potential of natural gas engine exhaust. The PAM chamber was used with a constant UV-light voltage, which resulted in relatively long equivalent atmospheric ages of 11 days at most. The studied retro-fitted natural gas engine exhaust was observed to form secondary aerosol. The mass of the total aged particles, i.e., particle mass measured downstream of the PAM chamber, was 6–268 times as high as the mass of the emitted primary exhaust particles. The secondary organic aerosol (SOA formation potential was measured to be 9–20 mg kgfuel−1. The total aged particles mainly consisted of organic matter, nitrate, sulfate and ammonium, with the fractions depending on exhaust after-treatment and the engine parameters used. Also, the volatility, composition and concentration of the total aged particles were found to depend on the engine operating mode, catalyst temperature and catalyst type. For example, a high catalyst temperature promoted the formation of sulfate particles, whereas a low catalyst temperature promoted nitrate formation. However, in particular, the concentration of nitrate needed a long time to stabilize – more than half an hour – which complicated the conclusions but also indicates the sensitivity of nitrate measurements on experimental parameters such as emission

  6. Cytokine expression in mice exposed to diesel exhaust particles by inhalation. Role of tumor necrosis factor

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    Loft Steffen

    2006-02-01

    Full Text Available Abstract Background Particulate air pollution has been associated with lung and cardiovascular disease, for which lung inflammation may be a driving mechanism. The pro-inflammatory cytokine, tumor necrosis factor (TNF has been suggested to have a key-role in particle-induced inflammation. We studied the time course of gene expression of inflammatory markers in the lungs of wild type mice and Tnf-/- mice after exposure to diesel exhaust particles (DEPs. Mice were exposed to either a single or multiple doses of DEP by inhalation. We measured the mRNA level of the cytokines Tnf and interleukin-6 (Il-6 and the chemokines, monocyte chemoattractant protein (Mcp-1, macrophage inflammatory protein-2 (Mip-2 and keratinocyte derived chemokine (Kc in the lung tissue at different time points after exposure. Results Tnf mRNA expression levels increased late after DEP-inhalation, whereas the expression levels of Il-6, Mcp-1 and Kc increased early. The expression of Mip-2 was independent of TNF if the dose was above a certain level. The expression levels of the cytokines Kc, Mcp-1 and Il-6, were increased in the absence of TNF. Conclusion Our data demonstrate that Tnf is not important in early DEP induced inflammation and rather exerts negative influence on Mcp-1 and Kc mRNA levels. This suggests that other signalling pathways are important, a candidate being one involving Mcp-1.

  7. Bioassay-directed fractionation and sub-fractionation for mutagenicity and chemical analysis of diesel exhaust particles

    NARCIS (Netherlands)

    Mutlu, E.; Warren, S.H.; Matthews, P.P.; King, C.; Linak, W.P.; Kooter, I.M.; Schmid, J.E.; Ross, J.A.; Ian Gilmour, M.; DeMarini, D.M.

    2013-01-01

    Several types of diesel exhaust particles (DEPs) have been used for toxicology studies, including a highorganic automobile DEP (A-DEP) from Japan, and a low-organic forklift DEP developed by the National Institute of Standards and Technology (N-DEP). However, these DEPs were not characterized

  8. Lack of acute phase response in the livers of mice exposed to diesel exhaust particles or carbon black by inhalation

    DEFF Research Database (Denmark)

    Saber, Anne T; Halappanavar, Sabina; Folkmann, Janne K

    2009-01-01

    phase responses, including C-reactive protein (CRP) and serum amyloid A (SAA) in humans. In this study we test the hypothesis that diesel exhaust particles (DEP) - or carbon black (CB)-induced lung inflammation initiates an acute phase response in the liver. RESULTS: Mice were exposed to filtered air...

  9. A laboratory investigation on the influence of adsorbed gases and particles from the exhaust of a kerosene burner on the evaporation rate of ice crystals and the ice nucleating ability of the exhaust particles

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, K.; Mitra, S.K.; Pruppacher, H.R. [Johannes Gutenberg Univ., Mainz (Germany). Inst. fuer Physik der Atmosphaere

    1997-12-31

    Laboratory experiments are described during which the influence of the exhausts of a kerosene burner on microphysical processes were studied. In one experimental investigation the evaporation rates of polluted ice crystals were compared with the evaporation rates of pure ice crystals. During another experimental investigation the ice nucleating ability of the exhaust particles was studied. The results show that the evaporation rate of polluted ice crystals was significantly reduced and also that ice nucleation takes place between -20 and -38 deg C. (author) 7 refs.

  10. Supercritical Regeneration of an Activated Carbon Fiber Exhausted with Phenol

    Directory of Open Access Journals (Sweden)

    M. Jesus Sanchez-Montero

    2018-01-01

    Full Text Available The properties of supercritical CO2 (SCCO2 and supercritical water (SCW turn them into fluids with a great ability to remove organic adsorbates retained on solids. These properties were used herein to regenerate an activated carbon fiber (ACF saturated with a pollutant usually contained in wastewater and drinking water, phenol. Severe regeneration conditions, up to 225 bar and 400 °C, had to be employed in SCCO2 regeneration to break the strong interaction established between phenol and the ACF. Under suitable conditions (regeneration temperature, time, and pressure, and flow of SCCO2 the adsorption capacity of the exhausted ACF was completely recovered, and even slightly increased. Most of the retained phenol was removed by thermal desorption, but the extra percentage removed by extraction allowed SCCO2 regeneration to be significantly more efficient than the classical thermal regeneration methods. SCCO2 regeneration and SCW regeneration were also compared for the first time. The use of SCW slightly improved regeneration, although SCW pressure was thrice SCCO2 pressure. The pathways that controlled SCW regeneration were also investigated.

  11. Method for the removal of smut, fine dust and exhaust gas particles, particle catch arrangement for use in this method and use of the particle catch arrangement to generate a static electric field

    NARCIS (Netherlands)

    Ursem, W.N.J.; Marijnissen, J.C.; Roos, R.A.

    2007-01-01

    This inventions provides a method for the removal of smut, fine dust and exhaust gas particles from polluted air comprising providing a particle catch arrangement with a charged surface, the particle catch arrangement being arranged to generate a static electric field, wherein the electric field is

  12. Health risk assessment for residents exposed to atmospheric diesel exhaust particles in southern region of Taiwan

    Science.gov (United States)

    Chio, Chia-Pin; Liao, Chung-Min; Tsai, Ying-I.; Cheng, Man-Ting; Chou, Wei-Chun

    2014-03-01

    Evidence shows a strong association among air pollution, oxidative stress (OS), deoxyribonucleic acid (DNA) damage, and diseases. Recent studies indicated that the aging, human neurodegenerative diseases and cancers resulted from mitochondrial dysfunction and OS. The purpose of this study is to provide a probabilistic risk assessment model to quantify the atmospheric diesel exhaust particles (DEP)-induced pre-cancer biomarker response and cancer incidence risk for residents in south Taiwan. We conducted entirely monthly particulate matter sampling data at five sites in Kaohsiung of south Taiwan in the period 2002-2003. Three findings were found: (i) the DEP dose estimates and cancer risk quantification had heterogeneously spatiotemporal difference in south Taiwan, (ii) the pre-cancer DNA damage biomarker and cancer incidence estimates had a positive yet insignificant association, and (iii) all the estimates of cancer incidence in south Taiwan populations fell within and slight lower than the values from previous cancer epidemiological investigations. In this study, we successfully assessed the tumor incidence for residents posed by DEP exposure in south Taiwan compared with the epidemiological approach. Our approach provides a unique way for assessing human health risk for residences exposed to atmospheric DEP depending on specific combinations of local and regional conditions. Our work implicates the importance of incorporating both environmental and health risk impacts into models of air pollution exposure to guide adaptive mitigation strategies.

  13. Diesel Exhaust Particles Induce Impairment of Vascular and Cardiac Homeostasis in Mice: Ameliorative Effect of Emodin

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    Abderrahim Nemmar

    2015-07-01

    Full Text Available Background/Aim: There is strong epidemiological and clinical evidence that components of the cardiovascular system are adversely affected by particulate air pollutants through the generation of inflammation and oxidative stress. Emodin (1,3,8-trihydroxy-6-methylanthraquinone, which is commonly found in the roots of rhubarb plant, has strong antioxidant and anti-inflammatory effects. However, its possible protective effect on the cardiovascular effect of particulate air pollutants has never been reported before. Methods: We tested, in Tuck-Ordinary mice, the possible ameliorative effect of emodin on the acute (24h cardiovascular effects of diesel exhaust particles (DEP, 1 mg/kg or saline (control. Emodin (4 mg/kg was administered intraperitoneally 1h before and 7h after pulmonary exposure to DEP. Twenty four h following DEP exposure, several cardiovascular endpoints were assessed. Results: Emodin significantly prevented the increase of leukocyte (n=8, Pin vivo prothrombotic effect of DEP in pial arterioles (n=6, Pin vitro in whole blood (n=4-5, PConclusion: We conclude that emodin treatment has consistently protected against DEP-induced impairment of vascular and cardiac homeostasis in mice. Our study provides experimental evidence that the use of functional food such as emodin, pending further studies, can be considered a useful agent and may have the potential to protect or mitigate the cardiovascular detrimental effects observed in people living in cities with high concentrations of particulate air pollution.

  14. Self-consistent coupling of DSMC method and SOLPS code for modeling tokamak particle exhaust

    Science.gov (United States)

    Bonelli, F.; Varoutis, S.; Coster, D.; Day, C.; Zanino, R.; Contributors, JET

    2017-06-01

    In this work, an investigation of the neutral gas flow in the JET sub-divertor area is presented, with respect to the interaction between the plasma side and the pumping side. The edge plasma side is simulated with the SOLPS code, while the sub-divertor area is modeled by means of the direct simulation Monte Carlo (DSMC) method, which in the last few years has proved well able to describe rarefied, collisional flows in tokamak sub-divertor structures. Four different plasma scenarios have been selected, and for each of them a user-defined, iterative procedure between SOLPS and DSMC has been established, using the neutral flux as the key communication term between the two codes. The goal is to understand and quantify the mutual influence between the two regions in a self-consistent manner, that is to say, how the particle exhaust pumping system controls the upstream plasma conditions. Parametric studies of the flow conditions in the sub-divertor, including additional flow outlets and variations of the cryopump capture coefficient, have been performed as well, in order to understand their overall impact on the flow field. The DSMC analyses resulted in the calculation of both the macroscopic quantities—i.e. temperature, number density and pressure—and the recirculation fluxes towards the plasma chamber. The consistent values for the recirculation rates were found to be smaller than those according to the initial standard assumption made by SOLPS.

  15. In utero exposure to a low concentration of diesel exhaust affects spontaneous locomotor activity and monoaminergic system in male mice

    Science.gov (United States)

    2010-01-01

    Background Epidemiological studies have suggested that suspended particulate matter (SPM) causes detrimental health effects such as respiratory and cardiovascular diseases, and that diesel exhaust particles from automobiles is a major contributor to SPM. It has been reported that neonatal and adult exposure to diesel exhaust damages the central nervous system (CNS) and induces behavioral alteration. Recently, we have focused on the effects of prenatal exposure to diesel exhaust on the CNS. In this study, we examined the effects of prenatal exposure to low concentration of diesel exhaust on behaviour and the monoaminergic neuron system. Spontaneous locomotor activity (SLA) and monoamine levels in the CNS were assessed. Methods Mice were exposed prenatally to a low concentration of diesel exhaust (171 μg DEP/m3) for 8 hours/day on gestational days 2-16. SLA was assessed for 3 days in 4-week-old mice by analysis of the release of temperature-associated infrared rays. At 5 weeks of age, the mice were sacrificed and the brains were used for analysis by high-performance liquid chromatography (HPLC). Results and Discussion Mice exposed to a low concentration of diesel exhaust showed decreased SLA in the first 60 minutes of exposure. Over the entire test period, the mice exposed prenatally to diesel exhaust showed decreased daily SLA compared to that in control mice, and the SLA in each 3 hour period was decreased when the lights were turned on. Neurotransmitter levels, including dopamine and noradrenaline, were increased in the prefrontal cortex (PFC) in the exposure group compared to the control group. The metabolites of dopamine and noradrenaline also increased in the PFC. Neurotransmitter turnover, an index of neuronal activity, of dopamine and noradrenaline was decreased in various regions of the CNS, including the striatum, in the exposure group. The serum corticosterone level was not different between groups. The data suggest that decreased SLA in mice exposed

  16. Effect of Locomotor Training on Exhaustion of Leg Muscle Activity in Chronic Complete Spinal Cord Injury.

    Science.gov (United States)

    Schrafl-Altermatt, Miriam; Dietz, Volker; Bolliger, Marc

    2017-08-01

    The aim of this study was to evaluate the effect of a continuous locomotor training on leg muscle electromyographic (EMG) exhaustion during assisted stepping movements in a patient with motor complete spinal cord injury (SCI). EMG exhaustion and loss of potentials starts to develop in untrained patients at ∼6 months after injury. In the trained patient examined in this study, exhaustion was also observed but occurred with a delay of several months. In contrast to an untrained patient, no more EMG exhaustion was observed in the very chronic stage. At this time (12 years after injury) a basic locomotor pattern of leg muscle activity of reduced amplitude could still be elicited, but it was resistant to exhaustion and unchanged in amplitude after 12 min of assisted stepping. It is suggested that fatigue-resistant motor units prevail at this stage and can still be activated during stepping as a result of the training.

  17. Oxidative DNA damage in vitamin C-supplemented guinea pigs after intratracheal instillation of diesel exhaust particles

    DEFF Research Database (Denmark)

    Moller, P.; Daneshvar, B.; Loft, S.

    2003-01-01

    The health effects of diesel exhaust particles (DEP) are thought to involve oxidative damage. We have investigated the effect of intratracheal DEP instillation to guinea pigs in three groups of 12 animals each given 0, 0.7, or 2.1 mg. Five days later guinea pigs exposed to DEP had increased levels...... for the study of oxidative damage induced by particulate matter. (C) 2003 Elsevier Science (USA). All rights reserved....

  18. Effect of diesel exhaust particles on renal vascular responses in rats with chronic kidney disease.

    Science.gov (United States)

    Al Suleimani, Y M; Al Mahruqi, A S; Al Za'abi, M; Shalaby, A; Ashique, M; Nemmar, A; Ali, B H

    2017-02-01

    Several recent studies have indicated the possible association between exposure to particulate air pollution and the increased rate of morbidity and mortality in patients with kidney diseases. The link of this observation to vascular damage has not been adequately addressed. Therefore, this study aims to investigate possible vascular damage that might be associated with exposure to diesel exhaust particles (DP) in adenine (AD)-induced chronic kidney disease (CKD) in rats, and the possible ameliorative effect of gum acacia (GA). CKD was induced by feeding AD (0.75%, w/w), and DP (0.5 mg/kg) was instilled intratracheally every second day and GA was given concomitantly in the drinking water at a dose of 15% w/v. All treatments were given concomitantly for 28 days. Changes in renal blood flow (RBF) and systolic and diastolic blood pressure were monitored in these animals after anesthesia, together with several other endpoints. Exposure to DP significantly reduced RBF and this was significantly potentiated in AD-treated rats. Phenylephrine-induced decreases in RBF and increases in systolic and diastolic blood pressure were severely potentiated in rats exposed to DP, and these actions were significantly augmented in AD-treated rats. GA did not significantly affect the vascular impairment induced by AD and DP given together. This study provides experimental evidence that exposure to particulate air pollution can exacerbate the vascular damage seen in patients with CKD. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 541-549, 2017. © 2016 Wiley Periodicals, Inc.

  19. Constraining the heterogeneous loss of O3 on soot particles with observations in jet engine exhaust plumes

    Science.gov (United States)

    Gao, R. S.; Kärcher, B.; Keim, E. R.; Fahey, D. W.

    In situ measurements in the engine exhaust of a Concorde supersonic aircraft in the lower stratosphere are used to constrain heterogeneous reaction rates on soot particles in a plume model. Upper limit values are obtained for the product of the reactive uptake coefficients of O3 and NO2 and the mean surface area of individual soot particles using the model and the well-established O3-N2O correlation in the lower stratosphere. The low reactivity value obtained for O3 implies that soot reactions cannot account for ozone trends in the lower stratosphere.

  20. Lack of acute phase response in the livers of mice exposed to diesel exhaust particles or carbon black by inhalation

    DEFF Research Database (Denmark)

    Saber, Anne T; Halappanavar, Sabina; Folkmann, Janne K

    2009-01-01

    BACKGROUND: Epidemiologic and animal studies have shown that particulate air pollution is associated with increased risk of lung and cardiovascular diseases. Although the exact mechanisms by which particles induce cardiovascular diseases are not known, studies suggest involvement of systemic acute...... phase responses, including C-reactive protein (CRP) and serum amyloid A (SAA) in humans. In this study we test the hypothesis that diesel exhaust particles (DEP) - or carbon black (CB)-induced lung inflammation initiates an acute phase response in the liver. RESULTS: Mice were exposed to filtered air...

  1. DNA adducts induced by in vitro activation of diesel and biodiesel exhaust extracts

    Science.gov (United States)

    The abstract reports the results of studies assessing the relative DNA damage potential of extracts of exhaust particles resulting from the combustion of petroleum diesel, biodiesel, and petroleum diesel-biodiesel blends. Results indicate that the commercially available B20 petr...

  2. Combined particle emission reduction and heat recovery from combustion exhaust - A novel approach for small wood-fired appliances

    Energy Technology Data Exchange (ETDEWEB)

    Messerer, A.; Poeschl, U.; Niessner, R. [Technical University of Munich, Munich (Germany). Institute of Hydrochemistry; Schmatloch, V. [EMPA, Swiss Federal Institute for Materials Research and Testing, Duebendorf (Switzerland)

    2007-07-15

    Replacing fossil fuels by renewable sources of energy is one approach to address the problem of global warming due to anthropogenic emissions of greenhouse gases. Wood combustion can help to replace fuel oil or gas. It is advisable, however, to use modern technology for combustion and exhaust gas after-treatment in order to achieve best efficiency and avoid air quality problems due to high emission levels often related to small scale wood combustion. In this study, simultaneous combustion particle deposition and heat recovery from the exhaust of two commercially available wood-fired appliances has been investigated. The experiments were performed with a miniature pipe bundle heat exchanger operating in the exhaust gas lines of a fully automated pellet burner or a closed fireplace. The system has been characterised for a wide range of aerosol inlet temperatures (135-295 {sup circle} C) and flow velocities (0.13-1.0ms{sup -1}), and particle deposition efficiencies up to 95% have been achieved. Deposition was dominated by thermophoresis and diffusion and increased with the average temperature difference and retention time in the heat exchanger. The aerosols from the two different appliances exhibited different deposition characteristics, which can be attributed to enhanced deposition of the nucleation mode particles generated in the closed fire place. The measured deposition efficiencies can be described by simple linear parameterisations derived from laboratory studies. The results of this study demonstrate the feasibility of thermophoretic particle removal from biomass burning flue gas and support the development of modified heat exchanger systems with enhanced capability for simultaneous heat recovery and particle deposition. (author)

  3. Experimental investigation of the effect of inlet particle properties on the capture efficiency in an exhaust particulate filter

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, Sandeep; Rothamer, David; Zelenyuk, Alla; Stewart, Mark; Bell, David

    2017-11-01

    The impact of inlet particle properties on the filtration performance of clean and particulate matter (PM) laden cordierite filter samples was evaluated using PM generated by a spark-ignition direct-injection (SIDI) engine fuelled with tier II EEE certification gasoline. Prior to the filtration experiments, a scanning mobility particle spectrometer (SMPS) was used to measure the electrical-mobility based particle size distribution (PSD) in the SIDI exhaust from distinct engine operating conditions. An advanced aerosol characterization system that comprised of a centrifugal particle mass analyser (CPMA), a differential mobility analyser (DMA), and a single particle mass spectrometer (SPLAT II) was used to obtain additional information on the SIDI particulate, including particle composition, mass, and dynamic shape factors (DSFs) in the transition () and free-molecular () flow regimes. During the filtration experiments, real-time measurements of PSDs upstream and downstream of the filter sample were used to estimate the filtration performance and the total trapped mass within the filter using an integrated particle size distribution method. The filter loading process was paused multiple times to evaluate the filtration performance in the partially loaded state. The change in vacuum aerodynamic diameter () distribution of mass-selected particles was examined for flow through the filter to identify whether preferential capture of particles of certain shapes occurred in the filter. The filter was also probed using different inlet PSDs to understand their impact on particle capture within the filter sample. Results from the filtration experiment suggest that pausing the filter loading process and subsequently performing the filter probing experiments did not impact the overall evolution of filtration performance. Within the present distribution of particle sizes, filter efficiency was independent of particle shape potentially due to the diffusion-dominant filtration

  4. Isolation and Quantitative Estimation of Diesel Exhaust and Carbon Black Particles Ingested by Lung Epithelial Cells and Alveolar Macrophages In Vitro

    Science.gov (United States)

    A new procedure for isolating and estimating ingested carbonaceous diesel exhaust particles (DEP) or carbon black (CB) particles by lung epithelial cells and macrophages is described. Cells were incubated with DEP or CB to examine cell-particle interaction and ingestion. After va...

  5. Ozone Enhances Diesel Exhaust Particles (DEP-Induced Interleukin-8 (IL-8 Gene Expression in Human Airway Epithelial Cells through Activation of Nuclear Factors- κB (NF-κB and IL-6 (NF-IL6

    Directory of Open Access Journals (Sweden)

    James Kelley

    2005-12-01

    Full Text Available Ozone, a highly reactive oxidant gas is a major component of photochemical smog. As an inhaled toxicant, ozone induces its adverse effects mainly on the lung. Inhalation of particulate matter has been reported to cause airway inflammation in humans and animals. Furthermore, epidemiological evidence has indicated that exposure to particulate matter (PM2.5-10, including diesel exhaust particles (DEP has been correlated with increased acute and chronic respiratory morbidity and exacerbation of asthma. Previously, exposure to ozone or particulate matter and their effect on the lung have been addressed as separate environmental problems. Ozone and particulate matter may be chemically coupled in the ambient air. In the present study we determined whether ozone exposure enhances DEP effect on interleukin-8 (IL-8 gene expression in human airway epithelial cells. We report that ozone exposure (0.5 ppm x 1 hr significantly increased DEP-induced IL-8 gene expression in A549 cells (117 ± 19 pg/ml, n = 6, p < 0.05 as compared to cultures treated with DEP (100 μg/ml x 4 hr alone (31 ± 3 pg/ml, n = 6, or cultures exposed to purified air (24 ± 6 pg/ml, n = 6. The increased DEP-induced IL-8 gene expression following ozone exposure was attributed to ozone-induced increase in the activity of the transcription factors NF-κB and NF-IL6. The results of the present study indicate that ozone exposure enhances the toxicity of DEP in human airway epithelial cells by augmenting IL-8 gene expression, a potent chemoattractant of neutrophils in the lung.

  6. Buildup of aerosol precursor gases and sulfur-induced activation of soot in nascent jet aircraft exhaust plumes

    Energy Technology Data Exchange (ETDEWEB)

    Kaercher, B.; Hirschberg, M.M.; Fabian, P. [Muenchen Univ. (Germany). Lehrstuhl fuer Bioklimatologie und Immissionsforschung; Gerz, T. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere

    1997-12-31

    Research issues concerning the chemical transformation of exhaust trace gases are summarized. The photochemical evolution of NO{sub x} early in the plume is strongly coupled to plume mixing. Substantial amounts of HNO{sub 3} are generated in nascent plumes even if no NO{sub 2} is emitted. The production of H{sub 2}SO{sub 4} becomes very efficient if part of the fuel sulfur is emitted as SO{sub 3}. Each emitted soot particle can acquire 1-10% by mass fully oxidized sulfur molecules prior to binary homogeneous nucleation, if a few percent of the exhaust SO{sub x} are emitted as SO{sub 3}, indicating an important activation pathway for soot, and leading to a marked enhancement of new aerosol formation and growth rates. (author) 11 refs.

  7. Tracking the pathway of diesel exhaust particles from the nose to the brain by X-ray florescence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Yasuto [Department of Urban and Environmental Engineering, Kyoto University, Katsura, Nishigyo-ku, Kyoto 606-8501 (Japan)], E-mail: y.matsui@health.env.kyoto-u.ac.jp; Sakai, Nobumitsu [Department of Urban and Environmental Engineering, Kyoto University, Katsura, Nishigyo-ku, Kyoto 606-8501 (Japan)], E-mail: sakai@health.env.kyoto-u.ac.jp; Tsuda, Akira [Molecular and Integrative Physiological Sciences, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115 (United States)], E-mail: atsuda@hsph.harvard.edu; Terada, Yasuko [JASRI, SPring-8, 1-1-1 Kouto, Sayo, Sayo-gun, Hyogo 679-5148 (Japan)], E-mail: yterada@spring8.or.jp; Takaoka, Masaki [Department of Urban and Environmental Engineering, Kyoto University, Katsura, Nishigyo-ku, Kyoto 606-8501 (Japan)], E-mail: takaoka@epsehost.env.kyoto-u.ac.jp; Fujimaki, Hidekazu [Division of Environmental Health Sciences, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan)], E-mail: fujimaki@nies.go.jp; Uchiyama, Iwao [Department of Urban and Environmental Engineering, Kyoto University, Katsura, Nishigyo-ku, Kyoto 606-8501 (Japan)], E-mail: uchiyama@health.env.kyoto-u.ac.jp

    2009-08-15

    Studies have shown that exposure to nano-sized particles (< 50 nm) result in their translocation to the central nervous system through the olfactory nerve. Translocation commonly occurs via inhalation, ingestion and skin uptake. Little information is available on the specific pathway of cellular localization of nano-sized particles in the olfactory bulb. The nano-sized particles entrance into the postsynaptics cell is of particular interest because the mitral cell projects to the central nucleus of the amygdala and the piriform cortex. Therefore, our objective in this follow-up study has been to determine whether or not the mitral cells project nano-sized particles to the brain. Nano-sized particles in this study were generated using diesel exhaust. Lab mice were exposed for a period of 4 weeks. We employed synchrotron radiation (SPring-8, Japan) to determine the concentration levels of metal in the olfactory neuron pathway. Metal levels were assayed by mapping, using X-ray fluorescence analysis. The major metal components measured in the filter that collected the inhaled diesel exhaust particles were calcium, copper, iron, nickel and zinc. Our studies reveal an increase in the amount of nano-sized particles in the glomerular layer as well as in the neurons in the olfactory epithelium. Higher levels of nickel and iron were found in the olfactory epithelium's lamina propria mucosae in comparison to that in the control group. Higher levels of iron also were observed in the glomerular layer. Our studies do not clarify the specifics of metal adhesion and detachment. This remains to be one of the key issues requiring further clarification.

  8. Influence of number and size of particles on the health risk from diesel and Otto engine exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, U.; Boehncke, A.; Mangelsdorf, I. (Fraunhofer-Institut fuer Toxikologie und Aerosolforschung, Hannover (Germany))

    1999-01-01

    On behalf of the German Umweltbundesamt (Federal Environmental Protection Agency), a comparative risk assessment is being carried out by the Fraunhofer Institute of Toxicology and Aerosol Research, Hannover, in cooperation with the German IFEU, (Institut fuer Energie- und Umweltforschung, Heidelberg), FoBiG (Forschungs- und Beratungsinstitut Gefahrstoffe GmbH, Freiburg) and Prof. Pott and Dr. Roller, Duesseldorf. Passenger cars with either gasoline or diesel engines as well as city busses with either CNG (Compressed Natural Gas) or diesel motor, are compared with regard to relevant exhaust components (including e.g. particulate matter, NO[sub x] and benzene) and current and future European emission standards. This risk assessment is based on emission rates for the individual exhaust components which have been deduced by IFEU from model calculations for the various European emission standards. These are connected mathematically with reference concentrations for the toxic effects of individual components and Unit Risks for their carcinogenic properties, so that a comparison of the toxic and carcinogenic potencies of the individual exhaust components is possible for the different motor types. A reference concentration of 3.5 [mu]g/m[sup 3] for the insoluble particle core and 5 [mu]g/m[sup 3] for the total particles, as derived by the WHO and US EPA, are used for the calculations in the risk assessment. The basis of the Unit Risk for the carcinogenic effects is 1 x 10[sup -4] [mu]g/m[sup 3] for the insoluble particle core and 7 x 10[sup -5] [mu]g/m[sup 3] for the total particles as derived by the German LAI (Laenderausschuss Immissionsschutz). Since the project is currently not yet finished, the main results are given briefly and qualitatively. (orig.)

  9. Influence of number and size of particles on the health risk from diesel and Otto engine exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, U.; Boehncke, A.; Mangelsdorf, I. [Fraunhofer-Institut fuer Toxikologie und Aerosolforschung, Hannover (Germany)

    1999-11-01

    On behalf of the German Umweltbundesamt (Federal Environmental Protection Agency), a comparative risk assessment is being carried out by the Fraunhofer Institute of Toxicology and Aerosol Research, Hannover, in cooperation with the German IFEU, (Institut fuer Energie- und Umweltforschung, Heidelberg), FoBiG (Forschungs- und Beratungsinstitut Gefahrstoffe GmbH, Freiburg) and Prof. Pott and Dr. Roller, Duesseldorf. Passenger cars with either gasoline or diesel engines as well as city busses with either CNG (Compressed Natural Gas) or diesel motor, are compared with regard to relevant exhaust components (including e.g. particulate matter, NO{sub x} and benzene) and current and future European emission standards. This risk assessment is based on emission rates for the individual exhaust components which have been deduced by IFEU from model calculations for the various European emission standards. These are connected mathematically with reference concentrations for the toxic effects of individual components and Unit Risks for their carcinogenic properties, so that a comparison of the toxic and carcinogenic potencies of the individual exhaust components is possible for the different motor types. A reference concentration of 3.5 {mu}g/m{sup 3} for the insoluble particle core and 5 {mu}g/m{sup 3} for the total particles, as derived by the WHO and US EPA, are used for the calculations in the risk assessment. The basis of the Unit Risk for the carcinogenic effects is 1 x 10{sup -4} {mu}g/m{sup 3} for the insoluble particle core and 7 x 10{sup -5} {mu}g/m{sup 3} for the total particles as derived by the German LAI (Laenderausschuss Immissionsschutz). Since the project is currently not yet finished, the main results are given briefly and qualitatively. (orig.)

  10. Analysis of the effects of meteorology on aircraft exhaust dispersion and deposition using a Lagrangian particle model

    Energy Technology Data Exchange (ETDEWEB)

    Pecorari, Eliana, E-mail: eliana.pecorari@unive.it [Department of Environmental Science, Informatics and Statistics, University Ca’ Foscari Venice, Calle Larga Santa Marta 2137, Dorsoduro, 30123 Venezia (Italy); Mantovani, Alice [OSMOTECH S.r.l., via Francesco Sforza, 15, 20122 Milano (Italy); Franceschini, Chiara [Department of Environmental Science, Informatics and Statistics, University Ca’ Foscari Venice, Calle Larga Santa Marta 2137, Dorsoduro, 30123 Venezia (Italy); Bassano, Davide [SAVE S.p.A., Marco Polo Venice airport viale G. Galilei 30/1, 30173 Tessera-Venezia (Italy); Palmeri, Luca [Department of Industrial Engineering, University of Padova, v. Marzolo 9, 35131 Padova (Italy); Rampazzo, Giancarlo [Department of Environmental Science, Informatics and Statistics, University Ca’ Foscari Venice, Calle Larga Santa Marta 2137, Dorsoduro, 30123 Venezia (Italy)

    2016-01-15

    The risk of air quality degradation is of considerable concern particularly for those airports that are located near urban areas. The ability to quantitatively predict the effects of air pollutants originated by airport operations is important for assessing air quality and the related impacts on human health. Current emission regulations have focused on local air quality in the proximity of airports. However, an integrated study should consider the effects of meteorological events, at both regional and local level, that can affect the dispersion and the deposition of exhausts. Rigorous scientific studies and extensive experimental data could contribute to the analysis of the impacts of airports expansion plans. This paper is focused on the analysis of the effects of meteorology on aircraft emission for the Marco Polo Airport in Venice. This is the most important international airport in the eastern part of the Po’ Valley, one of the most polluted area in Europe. Air pollution is exacerbated by meteorology that is a combination of large and local scale effects that do not allow significant dispersion. Moreover, the airport is located near Venice, a city of noteworthy cultural and architectural relevance, and nearby the lagoon that hosts several areas of outstanding ecological importance at European level (Natura 2000 sites). Dispersion and deposit of the main aircraft exhausts (NOx, HC and CO) have been evaluated by using a Lagrangian particle model. Spatial and temporal aircraft exhaust dispersion has been analyzed for LTO cycle. Aircraft taxiing resulted to be the most impacting aircraft operation especially for the airport working area and its surroundings, however occasionally peaks may be observed even at high altitudes when cruise mode starts. Mixing height can affect concentrations more significantly than the concentrations in the exhausts themselves. An increase of HC and CO concentrations (15–50%) has been observed during specific meteorological events

  11. Particle fallout/activity sensor

    Science.gov (United States)

    Curtis, Ihlefeld M. (Inventor); Youngquist, Robert C. (Inventor); Moerk, John S. (Inventor); Rose, Kenneth A., III (Inventor)

    1995-01-01

    A particle fallout/activity sensor measures relative amounts of dust or other particles which collect on a mirror in an area to be monitored. The sensor includes a sensor module and a data acquisition module, both of which can be operated independently of one another or in combination with one another. The sensor module includes a housing containing the mirror, an LED assembly for illuminating the mirror and an optical detector assembly for detecting light scattered off of the mirror by dust or other particles collected thereon. A microprocessor controls operation of the sensor module's components and displays results of a measurement on an LCD display mounted on the housing. A push button switch is also mounted on the housing which permits manual initiation of a measurement. The housing is constructed of light absorbing material, such as black delrin, which minimizes detection of light by the optical detector assembly other than that scattered by dust or particles on the mirror. The data acquisition module can be connected to the sensor module and includes its own microprocessor, a timekeeper and other digital circuitry for causing the sensor module to make a measurement periodically and send the measurement data to the data acquisition module for display and storage in memory for later retrieval and transfer to a separate computer. The time tagged measurement data can also be used to determine the relative level of activity in the monitored area since this level is directly related to the amount of dust or particle fallout in the area.

  12. Protective effect of curcumin on pulmonary and cardiovascular effects induced by repeated exposure to diesel exhaust particles in mice.

    Directory of Open Access Journals (Sweden)

    Abderrahim Nemmar

    Full Text Available Particulate air pollution has been associated with increased risk of cardiopulmonary diseases. However, the underlying mechanisms are not fully understood. We have previously demonstrated that single dose exposure to diesel exhaust particle (DEP causes lung inflammation and peripheral thrombotic events. Here, we exposed mice with repeated doses of DEP (15 µg/animal every 2(nd day for 6 days (a total of 4 exposures, and measured several cardiopulmonary endpoints 48 h after the end of the treatments. Moreover, the potential protective effect of curcumin (the yellow pigment isolated from turmeric on DEP-induced cardiopulmonary toxicity was assessed. DEP exposure increased macrophage and neutrophil numbers, tumor necrosis factor α (TNF α in the bronchoalveolar lavage (BAL fluid, and enhanced airway resistance to methacoline measured invasively using Flexivent. DEP also significantly increased plasma C-reactive protein (CRP and TNF α concentrations, systolic blood pressure (SBP as well as the pial arteriolar thrombosis. It also significantly enhanced the plasma D-dimer and plasminogen activator inhibitor-1 (PAI-1. Pretreatment with curcumin by oral gavage (45 mg/kg 1 h before exposure to DEP significantly prevented the influx of inflammatory cells and the increase of TNF α in BAL, and the increased airway resistance caused by DEP. Likewise, curcumin prevented the increase of SBP, CRP, TNF α, D-dimer and PAI-1. The thrombosis was partially but significantly mitigated. In conclusion, repeated exposure to DEP induced lung and systemic inflammation characterized by TNFα release, increased SBP, and accelerated coagulation. Our findings indicate that curcumin is a potent anti-inflammatory agent that prevents the release of TNFα and protects against the pulmonary and cardiovascular effects of DEP.

  13. Analysis of the effects of meteorology on aircraft exhaust dispersion and deposition using a Lagrangian particle model.

    Science.gov (United States)

    Pecorari, Eliana; Mantovani, Alice; Franceschini, Chiara; Bassano, Davide; Palmeri, Luca; Rampazzo, Giancarlo

    2016-01-15

    The risk of air quality degradation is of considerable concern particularly for those airports that are located near urban areas. The ability to quantitatively predict the effects of air pollutants originated by airport operations is important for assessing air quality and the related impacts on human health. Current emission regulations have focused on local air quality in the proximity of airports. However, an integrated study should consider the effects of meteorological events, at both regional and local level, that can affect the dispersion and the deposition of exhausts. Rigorous scientific studies and extensive experimental data could contribute to the analysis of the impacts of airports expansion plans. This paper is focused on the analysis of the effects of meteorology on aircraft emission for the Marco Polo Airport in Venice. This is the most important international airport in the eastern part of the Po' Valley, one of the most polluted area in Europe. Air pollution is exacerbated by meteorology that is a combination of large and local scale effects that do not allow significant dispersion. Moreover, the airport is located near Venice, a city of noteworthy cultural and architectural relevance, and nearby the lagoon that hosts several areas of outstanding ecological importance at European level (Natura 2000 sites). Dispersion and deposit of the main aircraft exhausts (NOx, HC and CO) have been evaluated by using a Lagrangian particle model. Spatial and temporal aircraft exhaust dispersion has been analyzed for LTO cycle. Aircraft taxiing resulted to be the most impacting aircraft operation especially for the airport working area and its surroundings, however occasionally peaks may be observed even at high altitudes when cruise mode starts. Mixing height can affect concentrations more significantly than the concentrations in the exhausts themselves. An increase of HC and CO concentrations (15-50%) has been observed during specific meteorological events

  14. Brain Activation Patterns at Exhaustion in Rats That Differ in Inherent Exercise Capacity

    Science.gov (United States)

    Foley, Teresa E.; Brooks, Leah R.; Gilligan, Lori J.; Burghardt, Paul R.; Koch, Lauren G.; Britton, Steven L.; Fleshner, Monika

    2012-01-01

    In order to further understand the genetic basis for variation in inherent (untrained) exercise capacity, we examined the brains of 32 male rats selectively bred for high or low running capacity (HCR and LCR, respectively). The aim was to characterize the activation patterns of brain regions potentially involved in differences in inherent running capacity between HCR and LCR. Using quantitative in situ hybridization techniques, we measured messenger ribonuclease (mRNA) levels of c-Fos, a marker of neuronal activation, in the brains of HCR and LCR rats after a single bout of acute treadmill running (7.5–15 minutes, 15° slope, 10 m/min) or after treadmill running to exhaustion (15–51 minutes, 15° slope, initial velocity 10 m/min). During verification of trait differences, HCR rats ran six times farther and three times longer prior to exhaustion than LCR rats. Running to exhaustion significantly increased c-Fos mRNA activation of several brain areas in HCR, but LCR failed to show significant elevations of c-Fos mRNA at exhaustion in the majority of areas examined compared to acutely run controls. Results from these studies suggest that there are differences in central c-Fos mRNA expression, and potential brain activation patterns, between HCR and LCR rats during treadmill running to exhaustion and these differences could be involved in the variation in inherent running capacity between lines. PMID:23028992

  15. Implication of scavenger receptors in the interactions between diesel exhaust particles and immature or mature dendritic cells

    Directory of Open Access Journals (Sweden)

    Lassalle Philippe

    2009-03-01

    Full Text Available Abstract Background The exposure to pollutants such as diesel exhaust particles (DEP is associated with an increased incidence of respiratory diseases. However, the mechanisms by which DEP have an effect on human health are not completely understood. In addition to their action on macrophages and airway epithelial cells, DEP also modulate the functions of dendritic cells (DC. These professional antigen-presenting cells are able to discriminate unmodified self from non-self thanks to pattern recognition receptors such as the Toll like Receptors (TLR and Scavenger Receptors (SR. SR were originally identified by their ability to bind and internalize modified lipoproteins and microorganisms but also particles and TLR agonists. In this study, we assessed the implication of SR in the effects of DEP associated or not with TLR agonists on monocyte-derived DC (MDDC. For this, we studied the regulation of CD36, CXCL16, LOX-1, SR-A1 and SR-B1 expression on MDDC treated with DEP associated or not with TLR2, 3 and 4 ligands. Then, the capacity of SR ligands (dextran sulfate and maleylated-ovalbumin to block the effects of DEP on the function of lipopolysaccharide (LPS-activated DC has been evaluated. Results Our data demonstrate that TLR2 agonists mainly augmented CXCL16, LOX-1 and SR-B1 expression whereas DEP alone had only a weak effect. Interestingly, DEP modulated the action of TLR2 and TLR4 ligands on the expression of LOX-1 and SR-B1. Pretreatment with the SR ligand maleylated-ovalbumin but not dextran sulfate inhibited the endocytosis of DEP by MDDC. Moreover, this SR ligand blocked the effect by DEP at low dose (1 μg/ml on MDDC phenotype (a decrease of CD86 and HLA-DR expression and on the secretion of CXCL10, IL-12 and TNF-α. In contrast, the decrease of IL-12 and CXCL10 secretion and the generation of oxygen metabolite induced by DEP at 10 μg/ml was not affected by SR ligands Conclusion Our results show for the first time that the modulation of

  16. Mutagenicity of diesel engine exhaust is eliminated in the gas phase by an oxidation catalyst but only slightly reduced in the particle phase.

    Science.gov (United States)

    Westphal, Götz A; Krahl, Jürgen; Munack, Axel; Ruschel, Yvonne; Schröder, Olaf; Hallier, Ernst; Brüning, Thomas; Bünger, Jürgen

    2012-06-05

    Concerns about adverse health effects of diesel engine emissions prompted strong efforts to minimize this hazard, including exhaust treatment by diesel oxidation catalysts (DOC). The effectiveness of such measures is usually assessed by the analysis of the legally regulated exhaust components. In recent years additional analytical and toxicological tests were included in the test panel with the aim to fill possible analytical gaps, for example, mutagenic potency of polycyclic aromatic hydrocarbons (PAH) and their nitrated derivatives (nPAH). This investigation focuses on the effect of a DOC on health hazards from combustion of four different fuels: rapeseed methyl ester (RME), common mineral diesel fuel (DF), SHELL V-Power Diesel (V-Power), and ARAL Ultimate Diesel containing 5% RME (B5ULT). We applied the European Stationary Cycle (ESC) to a 6.4 L turbo-charged heavy load engine fulfilling the EURO III standard. The engine was operated with and without DOC. Besides regulated emissions we measured particle size and number distributions, determined the soluble and solid fractions of the particles and characterized the bacterial mutagenicity in the gas phase and the particles of the exhaust. The effectiveness of the DOC differed strongly in regard to the different exhaust constituents: Total hydrocarbons were reduced up to 90% and carbon monoxide up to 98%, whereas nitrogen oxides (NO(X)) remained almost unaffected. Total particle mass (TPM) was reduced by 50% with DOC in common petrol diesel fuel and by 30% in the other fuels. This effect was mainly due to a reduction of the soluble organic particle fraction. The DOC caused an increase of the water-soluble fraction in the exhaust of RME, V-Power, and B5ULT, as well as a pronounced increase of nitrate in all exhausts. A high proportion of ultrafine particles (10-30 nm) in RME exhaust could be ascribed to vaporizable particles. Mutagenicity of the exhaust was low compared to previous investigations. The DOC reduced

  17. Oxidative damage to DNA by diesel exhaust particle exposure in co-cultures of human lung epithelial cells and macrophages

    DEFF Research Database (Denmark)

    Jantzen, Kim; Roursgaard, Martin; Madsen, Claus Desler

    2012-01-01

    Studies in mono-culture of cells have shown that diesel exhaust particles (DEPs) increase the production of reactive oxygen species (ROS) and oxidative stress-related damage to DNA. However, the level of particle-generated genotoxicity may depend on interplay between different cell types, e.g. lung...... relationship between levels of respiration and ROS production. In conclusion, exposure of mono-cultured cells to DEPs generated oxidative stress to DNA, whereas co-cultures with macrophages had lower levels of oxidatively damaged DNA than A549 epithelial cells....... treatment with standard reference DEPs, SRM2975 and SRM1650b. The exposure to DEPs did not affect the colony-forming ability of A549 cells in co-culture with THP-1a cells. The DEPs generated DNA strand breaks and oxidatively damaged DNA, measured using the alkaline comet assay as formamidopyrimidine...

  18. Numerical investigation of diesel exhaust particle transport and deposition in the CT-scan based lung airway

    Science.gov (United States)

    Islam, Mohammad S.; Saha, Suvash C.; Sauret, Emilie; Gu, Y. T.; Molla, Md Mamun

    2017-06-01

    Diesel exhaust particulates matter (DEPM) is a compound mixture of gasses and fine particles that contain more than 40 toxic air pollutants including benzene, formaldehyde, and nitrogen oxides. Exposure of DEPM to human lung airway during respiratory inhalation causes severe health hazards like diverse pulmonary diseases. This paper studies the DEPM transport and deposition in upper three generations of the realistic lung airways. A 3-D digital airway bifurcation model is constructed from the computerized tomography (CT) scan data of a healthy adult man. The Euler-Lagrange approach is used to solve the continuum and disperse phases of the calculation. Local averaged Navier-Stokes equations are solved to calculate the transport of the continuum phase. Lagrangian based Discrete Phase Model (DPM) is used to investigate the particle transport and deposition in the current anatomical model. The effects of size specific monodispersed particles on deposition are extensively investigated during different breathing pattern. The numerical results illustrate that particle diameter and breathing pattern have a substantial impact on particles transport and deposition in the tracheobronchial airways. The present realistic bifurcation model also depicts a new deposition hot spot which could advance the understanding of the therapeutic drug delivery system to the specific position of the respiratory airways.

  19. CD40 agonist converting CTL exhaustion via the activation of the mTORC1 pathway enhances PD-1 antagonist action in rescuing exhausted CTLs in chronic infection.

    Science.gov (United States)

    Xu, Aizhang; Wang, Rong; Freywald, Andrew; Stewart, Kristoffor; Tikoo, Suresh; Xu, Jianqing; Zheng, Changyu; Xiang, Jim

    2017-03-11

    Expansion of PD-1-expressing CD8 + cytotoxic T lymphocytes (CTLs) and associated CTL exhaustion are chief issues for ineffective virus-elimination in chronic infectious diseases. PD-1 blockade using antagonistic anti-PD-L1 antibodies results in a moderate conversion of CTL exhaustion. We previously demonstrated that CD40L signaling of ovalbumin (OVA)-specific vaccine, OVA-Texo, converts CTL exhaustion via the activation of the mTORC1 pathway in OVA-expressing adenovirus (AdVova)-infected B6 mice showing CTL inflation and exhaustion. Here, we developed AdVova-infected B6 and transgenic CD11c-DTR (termed AdVova-B6 and AdVova-CD11c-DTR) mice with chronic infection, and assessed a potential effect of CD40 agonist on the conversion of CTL exhaustion and on a potential enhancement of PD-1 antagonist action in rescuing exhausted CTLs in our chronic infection models. We demonstrate that a single dose of anti-CD40 alone can effectively convert CTL exhaustion by activating the mTORC1 pathway, leading to CTL proliferation, up-regulation of an effector-cytokine IFN-γ and the cytolytic effect in AdVova-B6 mice. Using anti-CD4 antibody and diphtheria toxin (DT) to deplete CD4 + T-cells and dendritic cells (DCs), we discovered that the CD40 agonist-induced conversion in AdVova-B6 and AdVova-CD11c-DTR mice is dependent upon host CD4 + T-cell and DC involvements. Moreover, CD40 agonist significantly enhances PD-1 antagonist effectiveness in rescuing exhausted CTLs in chronic infection. Taken together, our data demonstrate the importance of CD40 signaling in the conversion of CTL exhaustion and its ability to enhance PD-1 antagonist action in rescuing exhausted CTLs in chronic infection. Therefore, our findings may positively impact the design of new therapeutic strategies for chronic infectious diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Stokesian swimmers and active particles

    CERN Document Server

    Felderhof, B U

    2015-01-01

    The net steady state flow pattern of a distorting sphere is studied in the framework of the bilinear theory of swimming at low Reynolds number. It is argued that the starting point of a theory of interacting active particles should be based on such a calculation, since any arbitrarily chosen steady state flow pattern is not necessarily the result of a swimming motion. Furthermore, it is stressed that as a rule the phase of stroke is relevant in hydrodynamic interactions, so that the net flow pattern must be used with caution.

  1. Fucoidan Extracted from Hijiki Protects Brain Microvessel Endothelial Cells Against Diesel Exhaust Particle Exposure-Induced Disruption.

    Science.gov (United States)

    Choi, Young-Sook; Eom, Sang-Yong; Kim, In-Soo; Ali, Syed F; Kleinman, Michael T; Kim, Yong-Dae; Kim, Heon

    2016-05-01

    This study was performed to evaluate the protective effects of fucoidan against the decreased function of primary cultured bovine brain microvessel endothelial cells (BBMECs) after exposure to diesel exhaust particles (DEPs). BBMECs were extracted from bovine brains and cultured until confluent. To evaluate the function of BBMECs, we performed a permeability test using cell-by-cell equipment and by Western blot analysis for zonular occludens-1 (ZO-1), which is a tight junction protein of BMECs, and evaluated oxidative stress in BBMECs using the DCFH-DA assay and the CUPRAC-BCS assay. The increased oxidative stress in BBMECs following DEP exposure was suppressed by fucoidan. In addition, permeability of BBMECs induced by DEP exposure was decreased by fucoidan treatment. Our results showed that fucoidan protects against BBMEC disruption induced by DEP exposure. This study provides evidence that fucoidan might protect the central nervous system (CNS) against DEP exposure.

  2. Vitamin D supplementation decreases immune activation and exhaustion in HIV-1-infected youth.

    Science.gov (United States)

    Eckard, Allison Ross; O'Riordan, Mary Ann; Rosebush, Julia C; Lee, Seungeun Thera; Habib, Jakob G; Ruff, Joshua H; Labbato, Danielle; Daniels, Julie E; Uribe-Leitz, Monika; Tangpricha, Vin; Chahroudi, Ann; McComsey, Grace A

    2017-10-10

    Heightened immune activation and exhaustion drive HIV disease progression and co-morbidities. Vitamin D has pleiotropic immunomodulatory effects, but little is known about the effects of supplementation in HIV. Our study investigates changes in immune activation and exhaustion markers after 12 months of supplementation in virologically-suppressed HIV-infected youth with vitamin D insufficiency. This is a randomized, active-control, double-blind trial investigating with 3 different vitamin D 3 doses [18,000 (standard/active-control dose), 60,000 (moderate dose) and 120,000 IU/monthly (high dose)] in 8-26 year old HIV-infected youth on combination antiretroviral therapy with baseline serum 25-hydroxyvitamin D (25(OH)D) concentrations ≤30 ng/mL. Only subjects (N=51) who maintained an undetectable HIV-1 RNA over the 12-month study period were included in this analysis. Baseline serum 25(OH)D concentrations and immune activation/exhaustion markers were not different between groups. By 12 months, 25(OH)D increased significantly within each dosing group with the greatest increase and most sustained concentrations ≥30 ng/mL in the high-dose group. Overall, all measured markers decreased with CD4 activation (CD4+CD38+HLA-DR+), CD8 activation (CD8+CD38+HLA-DR+), CD4 exhaustion (CD4+CD38+HLA-DR+PD1+), and inflammatory monocytes (CD14+CD16+) reaching statistical significance. When analyzed separately, there were no significant decreases in the moderate- or standard-dose groups, but CD4 and CD8 activation and inflammatory monocytes decreased significantly in the high-dose group. Vitamin D supplementation decreased markers of T-cell activation/exhaustion and monocyte activation in HIV-infected youth, with subjects given the highest dose (120,000 IU/month) showing the greatest decreases. These data suggest that high-dose vitamin D supplementation may attenuate immune activation and exhaustion and serve as adjuvant therapy to antiretroviral therapy in HIV.

  3. Self-reported exhaustion associated with physical activity among older adults.

    Science.gov (United States)

    Tsutsumimoto, Kota; Doi, Takehiko; Shimada, Hiroyuki; Makizako, Hyuma; Yoshida, Daisuke; Uemura, Kazuki; Anan, Yuya; Park, Hyuntae; Suzuki, Takao

    2016-05-01

    Self-reported exhaustion (SE) is a clinical complaint that is associated with a wide range of chronic diseases. However, the association of SE with physical activity, physical function or cognitive function among the older adult Japanese population is unclear. The present study aimed to determine the prevalence of SE, as well as whether physical function, cognitive function and physical activity were significant covariates. A total of 4607 adults (mean age 71 years) were considered eligible for participation based on the study criteria. SE was evaluated using the Study of Osteoporotic Fracture Index. We also evaluated physical activity, physical function (grip strength, Timed Up & Go) and cognitive function (Mini-Mental State Examination, Trail Making Test part A and B, Symbol Digit Substitution Task). The prevalence of SE ranged from 40.9% to 55.0%, and significantly increased with age. The results of the multiple logistic regression analyses showed that in the adjusted model of the 65-69 years age group, physical activity, Timed Up & Go and Symbol Digit Substitution Task were independently associated with SE. In the 70-79 years age group, physical activity, Timed Up & Go, Trail Making Test part A and B and Symbol Digit Substitution Task were independently associated with exhaustion. Only physical activity was associated with exhaustion in the ≥80 years age group. The prevalence of SE increased with age in the older adult Japanese population. Exhaustion was strongly associated with reduced daily physical activity, especially in those aged ≥80 years. Further studies should be carried out to determine if physical activity causes SE. Geriatr Gerontol Int 2016; 16: 625-630. © 2015 Japan Geriatrics Society.

  4. Diesel exhaust activates and primes microglia: air pollution, neuroinflammation, and regulation of dopaminergic neurotoxicity.

    Science.gov (United States)

    Levesque, Shannon; Taetzsch, Thomas; Lull, Melinda E; Kodavanti, Urmila; Stadler, Krisztian; Wagner, Alison; Johnson, Jo Anne; Duke, Laura; Kodavanti, Prasada; Surace, Michael J; Block, Michelle L

    2011-08-01

    Air pollution is linked to central nervous system disease, but the mechanisms responsible are poorly understood. Here, we sought to address the brain-region-specific effects of diesel exhaust (DE) and key cellular mechanisms underlying DE-induced microglia activation, neuroinflammation, and dopaminergic (DA) neurotoxicity. Rats were exposed to DE (2.0, 0.5, and 0 mg/m3) by inhalation over 4 weeks or as a single intratracheal administration of DE particles (DEP; 20 mg/kg). Primary neuron-glia cultures and the HAPI (highly aggressively proliferating immortalized) microglial cell line were used to explore cellular mechanisms. Rats exposed to DE by inhalation demonstrated elevated levels of whole-brain IL-6 (interleukin-6) protein, nitrated proteins, and IBA-1 (ionized calcium-binding adaptor molecule 1) protein (microglial marker), indicating generalized neuroinflammation. Analysis by brain region revealed that DE increased TNFα (tumor necrosis factor-α), IL-1β, IL-6, MIP-1α (macrophage inflammatory protein-1α) RAGE (receptor for advanced glycation end products), fractalkine, and the IBA-1 microglial marker in most regions tested, with the midbrain showing the greatest DE response. Intratracheal administration of DEP increased microglial IBA-1 staining in the substantia nigra and elevated both serum and whole-brain TNFα at 6 hr posttreatment. Although DEP alone failed to cause the production of cytokines and chemokines, DEP (5 μg/mL) pretreatment followed by lipopolysaccharide (2.5 ng/mL) in vitro synergistically amplified nitric oxide production, TNFα release, and DA neurotoxicity. Pretreatment with fractalkine (50 pg/mL) in vitro ameliorated DEP (50 μg/mL)-induced microglial hydrogen peroxide production and DA neurotoxicity. Together, these findings reveal complex, interacting mechanisms responsible for how air pollution may cause neuroinflammation and DA neurotoxicity.

  5. Measurement of the light absorbing properties of diesel exhaust particles using a three-wavelength photoacoustic spectrometer

    Science.gov (United States)

    Guo, Xuesong; Nakayama, Tomoki; Yamada, Hiroyuki; Inomata, Satoshi; Tonokura, Kenichi; Matsumi, Yutaka

    2014-09-01

    Diesel-exhaust particles (DEP) are one of the main anthropogenic sources of black carbon (BC) and organic matter (OM). Understanding the optical properties of DEP, including the enhancement of light absorption by BC due to coating and light absorption by OM, is important for evaluating the climate impact of DEP. In this study, a three-wavelength photoacoustic soot spectrometer (405, 532, and 781 nm) was used to investigate the wavelength-dependent optical properties of DEP emitted from a diesel engine vehicle running on a chassis dynamometer in transient driving mode (JE-05) and at a constant speed (either idling or driving at 70 km/h). Optical properties were measured after passing the diluted exhaust through a heater, set at 20, 47, or 300 °C (transient driving mode) or between 20 and 400 °C (constant driving mode). The OM accounted for, on average, ∼40 and ∼35% of the total mass concentration of DEP during the transient and constant driving modes, respectively. In transient driving mode, enhancements of scattering coefficients at 20 and 47 °C, and of the mass concentration of organics, were observed during the high-speed driving period (∼80 km/h) corresponding to driving on a highway. No difference was observed in the absorption coefficients between heated and unheated particles at 781 nm for either the transient (including the high-speed driving period) or constant driving modes. These results indicate a lack of enhancement due to the lensing effect, possibly because the BC was mainly mixed externally with the OM or because it was located at the edges of particles under these experimental conditions. Contributions to total light absorption at 405 nm by the OM were estimated by comparing the wavelength dependence of the absorption coefficients with and without heating. A significant contribution by light-absorbing OM (20 ± 7%) to total light absorption at 405 nm was observed during the high-speed driving period of the JE-05 mode, while the

  6. DNA strand breaks, acute phase response and inflammation following pulmonary exposure by instillation to the diesel exhaust particle NIST1650b in mice

    DEFF Research Database (Denmark)

    Kyjovska, Zdenka O.; Jacobsen, Nicklas R.; Saber, Anne T.

    2015-01-01

    We investigated the inflammatory response, acute phase response and genotoxic effect of diesel exhaust particles (DEPs, NIST1650b) following a single intratracheal instillation. C57BL/6J BomTac mice received 18, 54 or 162 µg/mouse and were killed 1, 3 and 28 days post-exposure. Vehicle controls a...

  7. Subscale Validation of the Subsurface Active Filtration of Exhaust (SAFE) Approach to the NTP Ground Testing

    Science.gov (United States)

    Marshall, William M.; Borowski, Stanley K.; Bulman, Mel; Joyner, Russell; Martin, Charles R.

    2015-01-01

    Nuclear thermal propulsion (NTP) has been recognized as an enabling technology for missions to Mars and beyond. However, one of the key challenges of developing a nuclear thermal rocket is conducting verification and development tests on the ground. A number of ground test options are presented, with the Sub-surface Active Filtration of Exhaust (SAFE) method identified as a preferred path forward for the NTP program. The SAFE concept utilizes the natural soil characteristics present at the Nevada National Security Site to provide a natural filter for nuclear rocket exhaust during ground testing. A validation method of the SAFE concept is presented, utilizing a non-nuclear sub-scale hydrogen/oxygen rocket seeded with detectible radioisotopes. Additionally, some alternative ground test concepts, based upon the SAFE concept, are presented. Finally, an overview of the ongoing discussions of developing a ground test campaign are presented.

  8. Exhaustion of Activated CD8 T Cells Predicts Disease Progression in Primary HIV-1 Infection

    Science.gov (United States)

    Hickling, Stephen; Hurst, Jacob; Meyerowitz, Jodi; Willberg, Christian B.; Robinson, Nicola; Brown, Helen; Kinloch, Sabine; Babiker, Abdel; Nwokolo, Nneka; Fox, Julie; Fidler, Sarah; Phillips, Rodney; Frater, John

    2016-01-01

    The rate at which HIV-1 infected individuals progress to AIDS is highly variable and impacted by T cell immunity. CD8 T cell inhibitory molecules are up-regulated in HIV-1 infection and associate with immune dysfunction. We evaluated participants (n = 122) recruited to the SPARTAC randomised clinical trial to determine whether CD8 T cell exhaustion markers PD-1, Lag-3 and Tim-3 were associated with immune activation and disease progression. Expression of PD-1, Tim-3, Lag-3 and CD38 on CD8 T cells from the closest pre-therapy time-point to seroconversion was measured by flow cytometry, and correlated with surrogate markers of HIV-1 disease (HIV-1 plasma viral load (pVL) and CD4 T cell count) and the trial endpoint (time to CD4 count exhaustion markers, expression of CD38 on CD8 T cells increased the strength of associations. In Cox models, progression to the trial endpoint was most marked for PD-1/CD38 co-expressing cells, with evidence for a stronger effect within 12 weeks from confirmed diagnosis of PHI. The effect of PD-1 and Lag-3 expression on CD8 T cells retained statistical significance in Cox proportional hazards models including antiretroviral therapy and CD4 count, but not pVL as co-variants. Expression of ‘exhaustion’ or ‘immune checkpoint’ markers in early HIV-1 infection is associated with clinical progression and is impacted by immune activation and the duration of infection. New markers to identify exhausted T cells and novel interventions to reverse exhaustion may inform the development of novel immunotherapeutic approaches. PMID:27415828

  9. Pulmonary exposure to diesel exhaust particles induces airway inflammation and cytokine expression in NC/Nga mice

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Ken-ichiro; Yanagisawa, Rie [National Institute for Environmental Studies, Inhalation Toxicology and Pathophysiology Research Team, Tsukuba (Japan); Takano, Hirohisa [National Institute for Environmental Studies, Inhalation Toxicology and Pathophysiology Research Team, Tsukuba (Japan); Kyoto Prefectural University of Medicine, Inflammation and Immunology, Graduate School of Medical Science, Kyoto (Japan); Ichinose, Takamichi [Oita University of Nursing and Health Science, Department of Health Science, Oita (Japan); Shimada, Akinori [Tottori University, Department of Veterinary Pathology, Faculty of Agriculture, Tottori (Japan); Yoshikawa, Toshikazu [Kyoto Prefectural University of Medicine, Inflammation and Immunology, Graduate School of Medical Science, Kyoto (Japan)

    2005-10-01

    Although several studies have reported that diesel exhaust particles (DEP) affect cardiorespiratory health in animals and humans, the effect of DEP on animal models with spontaneous allergic disorders has been far less intensively studied. The Nc/Nga mouse is known to be a typical animal model for human atopic dermatitis (AD). In the present study, we investigated the effects of repeated pulmonary exposure to DEP on airway inflammation and cytokine expression in NC/Nga mice. The animals were randomized into two experimental groups that received vehicle or DEP by intratracheal instillation weekly for six weeks. Cellular profiles of bronchoalveolar lavage (BAL) fluid and expressions of cytokines and chemokines in both the BAL fluid and lung tissues were evaluated 24 h after the last instillation. The DEP challenge produced an increase in the numbers of total cells, neutrophils, and mononuclear cells in BAL fluid as compared to the vehicle challenge (P<0.01). DEP exposure significantly induced the lung expressions of interleukin (IL)-4, keratinocyte chemoattractant (KC), and macrophage inflammatory protein (MIP)-1{alpha} when compared to the vehicle challenge. These results indicate that intratracheal exposure to DEP induces the recruitment of inflammatory cells, at least partially, through the local expression of IL-4 and chemokines in NC/Nga mice. (orig.)

  10. The aryl hydrocarbon receptor-mediated and genotoxic effects of fractionated extract of standard reference diesel exhaust particle material in pulmonary, liver and prostate cells.

    Science.gov (United States)

    Pálková, Lenka; Vondráček, Jan; Trilecová, Lenka; Ciganek, Miroslav; Pěnčíková, Kateřina; Neča, Jiří; Milcová, Alena; Topinka, Jan; Machala, Miroslav

    2015-04-01

    Diesel exhaust particles (DEP) and the associated complex mixtures of organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), or their derivatives, have been suggested to exert deleterious effects on human health. We used a set of defined cellular models representing liver, lung and prostate tissues, in order to compare non-genotoxic and genotoxic effects of crude and fractionated extract of a standard reference DEP material - SRM 1650b. We focused on the aryl hydrocarbon receptor (AhR)-mediated activity, modulation of cell proliferation, formation of DNA adducts, oxidative DNA damage, and induction of DNA damage responses, including evaluation of apoptosis, and phosphorylation of p53 tumor suppressor and checkpoint kinases (Chk). Both PAHs and the polar aromatic compounds contributed to the AhR-mediated activity of DEP-associated organic pollutants. The principal identified AhR agonists included benzo[k]fluoranthene, indeno[1,2,3-c,d]pyrene, chrysene and several non-priority PAHs, including benzochrysenes and methylated PAHs. In contrast to PAHs, polar compounds contributed more significantly to overall formation of DNA adducts associated with phosphorylation of p53, Chk1 or Chk2, and partly with apoptosis. Therefore, more attention should be paid to identification of DEP-associated polar organic compounds, contributing to the AhR activation and cytotoxic/genotoxic effects of complex airborne mixtures of organic contaminants produced by diesel engines. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Designing, construction, assessment, and efficiency of local exhaust ventilation in controlling crystalline silica dust and particles, and formaldehyde in a foundry industry plant.

    Science.gov (United States)

    Morteza, Mortezavi Mehrizi; Hossein, Kakooi; Amirhossein, Matin; Naser, Hasheminegad; Gholamhossein, Halvani; Hossein, Fallah

    2013-01-01

    The purpose of the present study was to design and assess the efficiency of a local exhaust ventilation system used in a foundry operation to control inhalable dust and particles, microcrystal particles, and noxious gases and vapours affecting workers during the foundry process. It was designed based on recommendations from the American Conference of Governmental Industrial Hygiene. After designing a local exhaust ventilation system (LEV), we prepared and submitted the implementation plan to the manufacturer. High concentrations of crystalline silica dust and formaldehyde, which are common toxic air pollutants in foundries, were ultimately measured as an indicator for studying the efficiency of this system in controlling inhalable dust and particles as well as other air pollutants. The level of occupational exposure to silica and formaldehyde as major air pollutants was assessed in two modes: first, when the LEV was on, and second, when it was off. Air samples from the exposure area were obtained using a personal sampling pump and analysed using the No. 7601 method for crystal silica and the No. 2541 method for formaldehyde of the National Institute for Occupational Safety and Health (NIOSH). Silica and formaldehyde concentrations were determined by visible absorption spectrophotometry and gas chromatography. The results showed that local exhaust ventilation was successful in preserving the crystal silica particles in the work environment at a level below the NIOSH maximum allowed concentration (0.05 mg m-3). In contrast, formaldehyde exceeded the NIOSH limit (1 ppm or 1.228 mg m-3).

  12. Lack of acute phase response in the livers of mice exposed to diesel exhaust particles or carbon black by inhalation

    Directory of Open Access Journals (Sweden)

    Williams Andrew

    2009-04-01

    Full Text Available Abstract Background Epidemiologic and animal studies have shown that particulate air pollution is associated with increased risk of lung and cardiovascular diseases. Although the exact mechanisms by which particles induce cardiovascular diseases are not known, studies suggest involvement of systemic acute phase responses, including C-reactive protein (CRP and serum amyloid A (SAA in humans. In this study we test the hypothesis that diesel exhaust particles (DEP – or carbon black (CB-induced lung inflammation initiates an acute phase response in the liver. Results Mice were exposed to filtered air, 20 mg/m3 DEP or CB by inhalation for 90 minutes/day for four consecutive days; we have previously shown that these mice exhibit pulmonary inflammation (Saber AT, Bornholdt J, Dybdahl M, Sharma AK, Loft S, Vogel U, Wallin H. Tumor necrosis factor is not required for particle-induced genotoxicity and pulmonary inflammation., Arch. Toxicol. 79 (2005 177–182. As a positive control for the induction of an acute phase response, mice were exposed to 12.5 mg/kg of lipopolysaccharide (LPS intraperitoneally. Quantitative real time RT-PCR was used to examine the hepatic mRNA expression of acute phase proteins, serum amyloid P (Sap (the murine homologue of Crp and Saa1 and Saa3. While significant increases in the hepatic expression of Sap, Saa1 and Saa3 were observed in response to LPS, their levels did not change in response to DEP or CB. In a comprehensive search for markers of an acute phase response, we analyzed liver tissue from these mice using high density DNA microarrays. Globally, 28 genes were found to be significantly differentially expressed in response to DEP or CB. The mRNA expression of three of the genes (serine (or cysteine proteinase inhibitor, clade A, member 3C, apolipoprotein E and transmembrane emp24 domain containing 3 responded to both exposures. However, these changes were very subtle and were not confirmed by real time RT

  13. Complementary role of HCV and HIV in T-cell activation and exhaustion in HIV/HCV coinfection.

    Science.gov (United States)

    Feuth, Thijs; Arends, Joop E; Fransen, Justin H; Nanlohy, Nening M; van Erpecum, Karel J; Siersema, Peter D; Hoepelman, Andy I M; van Baarle, Debbie

    2013-01-01

    To investigate whether T-cell activation and exhaustion is linked to HCV- and HIV disease parameters in HIV/HCV infected individuals, we studied T-cell characteristics in HIV/HCV coinfected patients and controls. 14 HIV/HCV coinfected, 19 HCV monoinfected, 10 HIV monoinfected patients and 15 healthy controls were included in this cross-sectional study. Differences in expression of activation and exhaustion markers (HLA-DR, CD38, PD-1, Tim-3 and Fas) and phenotypic markers on CD4(+) and CD8(+) T-cells were analysed by flow cytometry and were related to HCV disease parameters (HCV-viremia, ALT and liver fibrosis). Frequencies of activated CD4(+) and CD8(+) T-cells were higher in HIV/HCV-coinfected compared to healthy controls and HCV or HIV mono-infected individuals. Coinfected patients also showed high expression of the exhaustion marker PD-1 and death receptor Fas. In contrast, the exhaustion marker Tim-3 was only elevated in HIV-monoinfected patients. T-cell activation and exhaustion were correlated with HCV-RNA, suggesting that viral antigen influences T-cell activation and exhaustion. Interestingly, increased percentages of effector CD8(+) T-cells were found in patients with severe (F3-F4) liver fibrosis compared to those with no to minimal fibrosis (F0-F2). HIV/HCV coinfected patients display a high level of T-cell activation and exhaustion in the peripheral blood. Our data suggest that T-cell activation and exhaustion are influenced by the level of HCV viremia. Furthermore, high percentages of cytotoxic/effector CD8(+) T-cells are associated with liver fibrosis in both HCV monoinfected and HIV/HCV coinfected patients.

  14. Sublingual Nucleotides Prolong Run Time to Exhaustion in Young Physically Active Men

    Directory of Open Access Journals (Sweden)

    Sergej M. Ostojic

    2013-11-01

    Full Text Available Although dietary nucleotides have been determined to be required for normal immune function, there is limited direct interventional evidence confirming performance-enhancing effects of sublingual nucleotides in humans. A double-blind, placebo-controlled, randomized trial was conducted to evaluate the effect of sublingual nucleotides (50 mg/day administered for 14 days in thirty young healthy physically active males, on endurance performance and immune responses. Fasting white blood cell count, natural killer cells (NKC number, NKC cytotoxic activity, and serum immunoglobulin (IgA, IgM, IgG, and time to exhaustion, peak rate of perceived exertion, peak heart rate, and peak running speed during the exercise test were measured at baseline (day 0 and post-intervention (day 14. Time to exhaustion, as well as serum immunoglobulin A and NKC cytotoxic activity, were significantly higher at day 14 (p < 0.05 in participants supplemented with nucleotides compared with those who consumed placebo. No significant differences in other parameters were observed between groups at post-intervention. No volunteers withdrew before the end of the study nor reported any vexatious side effects of supplementation. The results of the present study suggest that sublingual nucleotides may provide pertinent benefit as both an ergogenic and immunostimulatory additive in active males.

  15. Regeneration of siloxane-exhausted activated carbon by advanced oxidation processes.

    Science.gov (United States)

    Cabrera-Codony, Alba; Gonzalez-Olmos, Rafael; Martín, Maria J

    2015-03-21

    In the context of the biogas upgrading, siloxane exhausted activated carbons need to be regenerated in order to avoid them becoming a residue. In this work, two commercial activate carbons which were proved to be efficient in the removal of octamethylcyclotetrasiloxane (D4) from biogas, have been regenerated through advanced oxidation processes using both O3 and H2O2. After the treatment with O3, the activated carbon recovered up to 40% of the original adsorption capacity while by the oxidation with H2O2 the regeneration efficiency achieved was up to 45%. In order to enhance the H2O2 oxidation, activated carbon was amended with iron. In this case, the regeneration efficiency increased up to 92%. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Cytokine responses induced by diesel exhaust particles are suppressed by PAR-2 silencing and antioxidant treatment, and driven by polar and non-polar soluble constituents.

    Science.gov (United States)

    Bach, Nicolai; Bølling, Anette Kocbach; Brinchmann, Bendik C; Totlandsdal, Annike I; Skuland, Tonje; Holme, Jørn A; Låg, Marit; Schwarze, Per E; Øvrevik, Johan

    2015-10-14

    Adsorbed soluble organics seem to be the main drivers of inflammatory responses induced by diesel exhaust particles (DEP). The specific compounds contributing to this process and the cellular mechanisms behind DEP-induced inflammation are not well known. We have assessed pro-inflammatory effects of DEP and various soluble DEP fractions, in human bronchial epithelial cells (BEAS-2B). DEP increased the expression of interleukin (IL)-6 and CXCL8. Silencing of the aryl hydrocarbon receptor (AhR) by siRNA or pretreatment with AhR-antagonists did not attenuate DEP-induced IL-6 and CXCL8 responses. However, the halogenated aromatic hydrocarbon (HAH)-selective AhR antagonist CH223191 caused a considerable reduction in DEP-induced CYP1A1 expression indicating that this response may be due to dioxin or dioxin-like constituents in DEP. Knock-down of protease activated receptor (PAR)-2 attenuated IL-6 responses without affecting CXCL8. Antioxidants did not affect IL-6 expression after 4h DEP-exposure and only partly reduced CXCL8 expression. However, after 24h exposure antioxidant treatment partly suppressed IL-6 protein release and completely blocked CXCL8 release. Furthermore, a heptane-soluble (non-polar) extract of DEP induced both IL-6 and CXCL8 release, whereas a PBS-soluble (highly polar) extract induced only IL-6. Thus, pro-inflammatory responses in DEP-exposed epithelial cells appear to be the result of both reactive oxygen species and receptor signaling, mediated through combinatorial effects between both non-polar and polar constituents adhered to the particle surface. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  17. Diesel exhaust particles increase IL-1β-induced human β-defensin expression via NF-κB-mediated pathway in human lung epithelial cells

    Directory of Open Access Journals (Sweden)

    Lee Chun

    2006-05-01

    Full Text Available Abstract Background Human β-defensin (hBD-2, antimicrobial peptide primarily induced in epithelial cells, is a key factor in the innate immune response of the respiratory tract. Several studies showed increased defensin levels in both inflammatory lung diseases, such as cystic fibrosis, diffuse panbronchiolitis, idiopathic pulmonary fibrosis and acute respiratory distress syndrome, and infectious diseases. Recently, epidemiologic studies have demonstrated acute and serious adverse effects of particulate air pollution on respiratory health, especially in people with pre-existing inflammatory lung disease. To elucidate the effect of diesel exhaust particles (DEP on pulmonary innate immune response, we investigated the hBD-2 and interleukin-8 (IL-8 expression to DEP exposure in interleukin-1 beta (IL-1β-stimulated A549 cells. Results IL-1β markedly up-regulated the hBD-2 promoter activity, and the subsequent DEP exposure increased dose-dependently the expression of hBD-2 and inflammatory cytokine IL-8 at the transcriptional level. In addition, DEP further induced the NF-κB activation in IL-1β-stimulated A549 cells more rapidly than in unstimulated control cells, which was showed by nuclear translocation of p65 NF-κB and degradation of IκB-α. The experiment using two NF-κB inhibitors, PDTC and MG132, confirmed that this increase of hBD-2 expression following DEP exposure was regulated through NF-κB-mediated pathway. Conclusion These results demonstrated that DEP exposure increases the expression of antimicrobial peptide and inflammatory cytokine at the transcriptional level in IL-1β-primed A549 epithelial cells and suggested that the increase is mediated at least partially through NF-κB activation. Therefore, DEP exposure may contribute to enhance the airway-responsiveness especially on the patients suffering from chronic respiratory disease.

  18. Aryl hydrocarbon receptor-dependent upregulation of Cyp1b1 by TCDD and diesel exhaust particles in rat brain microvessels

    Directory of Open Access Journals (Sweden)

    Jacob Aude

    2011-08-01

    Full Text Available Abstract Background AhR activates the transcription of several target genes including CYP1B1. Recently, we showed CYP1B1 as the major cytochrome P450 (CYP enzyme expressed in human brain microvessels. Here, we studied the effect of AhR activation by environmental pollutants on the expression of Cyp1b1 in rat brain microvessels. Methods Expression of AhR and Cyp1b1 was detected in isolated rat brain microvessels. AhR was immunovisualised in brain microvessel endothelial cells. The effect of AhR ligands on Cyp1b1 expression was studied using isolated brain microvessels after ex vivo and/or in vivo exposure to TCDD, heavy hydrocarbons containing diesel exhaust particles (DEP or Δ9-tetrahydrocannabinol (Δ9-THC. Results After ex vivo exposure to TCDD (a highly potent AhR ligand for 3 h, Cyp1b1 expression was significantly increased by 2.3-fold in brain microvessels. A single i.p. dose of TCDD also increased Cyp1b1 transcripts (22-fold and Cyp1b1 protein (2-fold in rat brain microvessels at 72 h after TCDD. Likewise, DEP treatment (in vivo and ex vivo strongly induced Cyp1b1 protein in brain microvessels. DEP-mediated Cyp1b1 induction was inhibited by actinomycin D, cycloheximide, or by an AhR antagonist. In contrast, a sub-chronic in vivo treatment with Δ9-THC once daily for 7 seven days had no effect on Cyp1b1 expression Conclusions Our results show that TCDD and DEP strongly induced Cyp1b1 in rat brain microvessels, likely through AhR activation.

  19. A Colorimetric Method for the Determination of the Exhaustion Level of Granular Activated Carbons Used in Rum Production

    Directory of Open Access Journals (Sweden)

    Harold Crespo Sariol

    2016-09-01

    Full Text Available Spectrophotometric measurement applied on saturated granular activated carbon (GAC is not yet explored. A colorimetric method in the visible range has been developed in order to determine the exhaustion level of GAC used in rum production. Aqueous ammonia solution has been used as an indicative agent to determine the extraction rate of taste compounds within the rum production process and the exhaustion degree of the GAC. The colorimetric results showed excellent correlation with the iodine number and the contact pH. The proposed colorimetric method opens possibilities for rum producers to improve the management and economical use of the activated carbon at the industrial scale.

  20. Exhaustion from prolonged gambling

    Directory of Open Access Journals (Sweden)

    Fatimah Lateef

    2013-01-01

    Full Text Available Complaints of fatigue and physical exhaustion are frequently seen in the acute medical setting, especially amongst athletes, army recruits and persons involved in strenuous and exertional physical activities. Stress-induced exhaustion, on the other hand, is less often seen, but can present with very similar symptoms to physical exhaustion. Recently, three patients were seen at the Department of Emergency Medicine, presenting with exhaustion from prolonged involvement in gambling activities. The cases serve to highlight some of the physical consequences of prolonged gambling.

  1. Increased extracellular dopamine and 5-hydroxytryptamine levels contribute to enhanced subthalamic nucleus neural activity during exhausting exercise

    Directory of Open Access Journals (Sweden)

    Y Hu

    2015-09-01

    Full Text Available The purpose of the study was to explore the mechanism underlying the enhanced subthalamic nucleus (STN neural activity during exhausting exercise from the perspective of monoamine neurotransmitters and changes of their corresponding receptors. Rats were randomly divided into microdialysis and immunohistochemistry study groups. For microdialysis study, extracellular fluid of the STN was continuously collected with a microdialysis probe before, during and 90 min after one bout of exhausting exercise. Dopamine (DA and 5-hydroxytryptamine (5-HT levels were subsequently detected with high-performance liquid chromatography (HPLC. For immunohistochemistry study, the expression of DRD 2 and HT 2C receptors in the STN, before, immediately after and 90 min after exhaustion was detected through immunohistochemistry technique. Microdialysis study results showed that the extracellular DA and 5-HT neurotransmitters increased significantly throughout the procedure of exhausting exercise and the recovery period (P0.05. Our results suggest that the increased extracellular DA and 5-HT in the STN might be one important factor leading to the enhanced STN neural activity and the development of fatigue during exhausting exercise. This study may essentially offer useful evidence for better understanding of the mechanism of the central type of exercise-induced fatigue.

  2. Pulmonary exposure to particles from diesel exhaust, urban dust or single-walled carbon nanotubes and oxidatively damaged DNA and vascular function in apoE(-/-)mice

    DEFF Research Database (Denmark)

    Vesterdal, Lise K; Jantzen, Kim; Sheykhzade, Majid

    2012-01-01

    Abstract This study compared the oxidative stress level and vasomotor dysfunction after exposure to urban dust, diesel exhaust particles (DEP) or single-walled carbon nanotubes (SWCNT). DEP and SWCNT increased the production of reactive oxygen species (ROS) in cultured endothelial cells......, Hmox-1 and Ogg1. The levels of oxidatively damaged DNA were unchanged in lung tissue. The exposure to SWCNT significantly increased the expression of Ccl-2 in the lung tissue of the mice. The exposure to DEP and SWCNT was associated with elevated ROS production in cultured cells, whereas intratracheal...

  3. Motorcycle exhaust particles up-regulate expression of vascular adhesion molecule-1 and intercellular adhesion molecule-1 in human umbilical vein endothelial cells.

    Science.gov (United States)

    Lee, Chen-Chen; Huang, Shih-Hsuan; Yang, Ya-Ting; Cheng, Yu-Wen; Li, Ching-Hao; Kang, Jaw-Jou

    2012-06-01

    Epidemiological studies have shown that there is a strong correlation between atherosclerosis and ambient air pollution. In this study, we found that motorcycle exhaust particles (MEP) induced adhesion between cells of the human monocytic leukemia cell line (THP-1) and human umbilical vein endothelial cells (HUVECs) in a time-and dose-dependent manner. In addition, MEP treatment induced both mRNA and protein expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) in HUVECs. The IκB degradation and p65 nuclear translocation was found in MEP-treated HUVECs, suggested the involvement of nuclear factor-κB (NF-κB). MEP-induced VCAM-1 and ICAM-1 protein expression was inhibited by NF-κB inhibitor BAY 11-7085. Oxidative stress was also involved in the signaling of VCAM-1 and ICAM-1 expression. MEP treatment caused hydrogen peroxide and superoxide formation. Pretreatment with α-tocopherol could inhibit MEP-induced reactive oxygen intermediates generation and suppressed MEP-induced IκB degradation and adhesion molecules expression. Furthermore, the carbon black (CB) nanoparticles with different diameters could induce VCAM-1 and ICAM-1 protein expression; however, polycyclic aromatic hydrocarbons (PAHs) only increased the expression of ICAM-1 but not that of VCAM-1 in HUVECs. In this study, we found that MEPs could induce ICAM-1 and VCAM-1 expression through oxidative stress and NF-κB activation in HUVECs. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Electromagnetics of active coated nano-particles

    DEFF Research Database (Denmark)

    Arslanagic, Samel

    2013-01-01

    This work reviews the fundamental properties of several spherical and cylindrical active coated nano-particles excited by their respective single and/or multiple sources of radiation at optical frequencies. Particular attention is devoted to the influence of the source location and orientation......, the optical gain constant and the nano-particle material composition on the electric and magnetic near fields, the power flow density, the radiated power as well as the directivities. Resonant as well as quasi-transparent states will be emphasized in the discussion....

  5. Complementary role of HCV and HIV in T-cell activation and exhaustion in HIV/HCV coinfection

    NARCIS (Netherlands)

    Feuth, T.; Arends, J.E.; Fransen, J.H.; Nanlohy, N.M.; Erpecum, K.J. van; Siersema, P.D.; Hoepelman, A.I.; Baarle, D. van

    2013-01-01

    OBJECTIVES: To investigate whether T-cell activation and exhaustion is linked to HCV- and HIV disease parameters in HIV/HCV infected individuals, we studied T-cell characteristics in HIV/HCV coinfected patients and controls. METHODS: 14 HIV/HCV coinfected, 19 HCV monoinfected, 10 HIV monoinfected

  6. Short-term effects of ultrafine particles on daily mortality by primary vehicle exhaust versus secondary origin in three Spanish cities.

    Science.gov (United States)

    Tobías, Aurelio; Rivas, Ioar; Reche, Cristina; Alastuey, Andrés; Rodríguez, Sergio; Fernández-Camacho, Rocío; Sánchez de la Campa, Ana M; de la Rosa, Jesús; Sunyer, Jordi; Querol, Xavier

    2018-02-01

    Evidence on the short-term effects of ultrafine particles (with diametervehicle exhaust (N1) and the second for the photochemical new particle formation enhancements (N2). We applied city-specific Poisson regression models, adjusting for long-term trends, temperature and population dynamics. Mean BC levels were higher in Barcelona and Tenerife (1.8 and 1.2μg·m -3 , respectively) than in Huelva (0.8μg·m -3 ). While mean UFP concentrations were similar in the three cities, from which N1 was 40% in Barcelona, 46% in Santa Cruz de Tenerife, and 27% in Huelva. We observed an association with N1 and daily mortality in Barcelona, by increasing approximately 1.5% between lags 0 and 2, per an interquartile increase (IQR) of 3277cm -3 , but not with N2. A similar pattern was found in Santa Cruz de Tenerife, although none of the associations were significant. Conversely, in the industrial city of Huelva mortality was associated with N2 at lag 0, by increasing 3.9% per an IQR of 12,032·cm -3 . The pattern and origin of UFP determines their short-term effect on human health. BC is possibly the better parameter to evaluate the health effects of particulate vehicle exhaust emissions, although in areas influenced by domestic solid fuel combustion this should also be taken into account. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Combusting vegetable oils in diesel engines: the impact of unsaturated fatty acids on particle emissions and mutagenic effects of the exhaust.

    Science.gov (United States)

    Bünger, Jürgen; Bünger, Jörn F; Krahl, Jürgen; Munack, Axel; Schröder, Olaf; Brüning, Thomas; Hallier, Ernst; Westphal, Götz A

    2016-06-01

    High particle emissions and strong mutagenic effects were observed after combustion of vegetable oil in diesel engines. This study tested the hypothesis that these results are affected by the amount of unsaturated or polyunsaturated fatty acids of vegetable oils. Four different vegetable oils (coconut oil, CO; linseed oil, LO; palm tree oil, PO; and rapeseed oil, RO) and common diesel fuel (DF) were combusted in a heavy-duty diesel engine. The exhausts were investigated for particle emissions and mutagenic effects in direct comparison with emissions of DF. The engine was operated using the European Stationary Cycle. Particle masses were measured gravimetrically while mutagenicity was determined using the bacterial reverse mutation assay with tester strains TA98 and TA100. Combustion of LO caused the largest amount of total particulate matter (TPM). In comparison with DF, it particularly raised the soluble organic fraction (SOF). RO presented second highest TPM and SOF, followed by CO and PO, which were scarcely above DF. RO revealed the highest number of mutations of the vegetable oils closely followed by LO. PO was less mutagenic, but still induced stronger effects than DF. While TPM and SOF were strongly correlated with the content of polyunsaturated fatty acids in the vegetable oils, mutagenicity had a significant correlation with the amount of total unsaturated fatty acids. This study supports the hypothesis that numbers of double bounds in unsaturated fatty acids of vegetable oils combusted in diesel engines influence the amount of emitted particles and the mutagenicity of the exhaust. Further investigations have to elucidate the causal relationship.

  8. Activity of different proteinaceous ice nucleating particles

    Science.gov (United States)

    Hartmann, Susann; Augustin-Bauditz, Stefanie; Grawe, Sarah; Ling, Meilee; Hellner, Lisa; Zapf, Jean-Michel; Šantl-Temkiv, Tina; Pummer, Bernhard; Boesen, Thomas; Wex, Heike; Finster, Kai; Stratmann, Frank

    2017-04-01

    A variety of microorganisms (bacteria, fungi, lichen) from land produce protein structures, which act as a template for ice nucleation [1]. Also marine sources of ice nucleating particles (INPs) came in focus in the recent years. The atmospheric spatio-temporal distribution of INPs from microorganisms is still not well known. However, it is often assumed that the observed onset of atmospheric ice nucleation (T>-20°C) is due to the existence of ice-nucleation active biological particles. In this study we compare the ice nucleation activity of different proteinaceous particles produced by bacteria and fungi. For bacteria we investigate (i) cells and fragments of Pseudomonas syringae from commercially available SnomaxTM and (ii) the Pseudomonas syringae INA protein expressed in living Escherichia coli bacteria. We also analyzed freeze-dried leaves [2] where we assume that proteinaceous particles are responsible for the ice nucleation activity. For fungi the widespread soil fungus Mortierella alpina was investigated which had been extracted from natural soil [3]. Immersion freezing experiments are performed at the cold stage LINA (Leipzig Ice Nucleation Array). We attempt to describe the activity of a single proteinaceous ice nucleating particle [4] in order to achieve direct comparability. Further, the results are compared with complex natural systems e.g. soil dust. The objectives of this study are to clarify potential differences in the ice nucleation potential of proteinaceous particles and to draw conclusions concerning the need to differentiate them for modelling purposes. 1. Szyrmer, W. and I. Zawadzki, Biogenic and anthropogenic sources of ice-forming nuclei: A review, Bull. Amer. Meteorol. Soc., 1997. 2. Schnell, R.C. and G. Vali, Biogenic ice nucleai .1: Terrestrial and marine sources, doi: 10.1175/1520-0469(1976)0332.0.co;2, 1976. 3. Froehlich-Nowoisky, J. et al., Ice nucleation activity in the widespread soil fungus Mortierella alpina, doi: 10.5194/bg-12

  9. In situ measurement of electrostatic charge and charge distribution on flyash particles in power station exhaust stream

    Energy Technology Data Exchange (ETDEWEB)

    Guang, D.

    1992-01-01

    The electrostatic charges and charge distributions on individual flyash particles were experimentally measured in situ at four power stations in New South Wales and in the laboratory with an Electrostatic Charge Classifier. The global charge of these flyashes was also measured. The electrostatic charge on flyash particles of four power stations was found to be globally native. The median charge on the flyash particles varies linearly with particle diameter for all four flyashes. The electrostatic charge on the Tallawarra flyash particles was found to increase after passage through the air heater having huge metal surface areas, suggesting that triboelectrification was the primary charging mechanism for flyash particles. Distinctly different characteristics of the electrostatic charge, particle size and particle shape were found between the Eraring and the Tallawarra flyashes. The spherical Eraring ash has the highest proportion of lines and positively charged particles, but the lowest global charge level among the four flyashes. In contrast, the Tallawarra flyash has just the opposite. It is the distinct characteristics of the flyashes from Eraring and Tallawarra power stations that are responsible for the significant differences in their baghouse performance. The napping feature on the surface of the filter bags used in the Eraring and Tallawarra power stations provides an upstream surface of low fibre density above the fabric bulk. This feature presents and advantage to highly charged particles, like the Tallawarra flyash particles. Highly charged particles tend to deposit on such an upstream surface resulting in a porous dust cake with much less contact areas with the fabric medium than would otherwise be formed. This cake is easy to remove and provides less resistance to the gas flow. After singeing the naps on the filter bag surface at the Eraring power station, the problems of high pressure drop and retention of dust cake on the bas surface have been resolved.

  10. Subjective recovery time after exhausting muscular activity in postpolio and control subjects.

    Science.gov (United States)

    Agre, J C; Rodriquez, A A; Franke, T M

    1998-01-01

    The purpose of this study was to determine whether the time to subjectively fully recover after the performance of exhausting muscular exercise was greater in unstable postpolio as compared with stable postpolio or control subjects. Twenty-five unstable (those complaining of declining muscle strength) postpolio, 16 stable (those denying declining muscle strength) postpolio, and 25 control subjects performed an isometric contraction of the knee extensor (quadriceps femoris) musculature at 40% of maximal torque until they were no longer able to do so. Five-second maximal effort contractions were made every 30 s through 2 min after the time of failure was reached and then at 1-min intervals through 10 min after failure was reached. Subjects reported the duration of time required to subjectively fully recover from this activity. Choices of "less than 1 day," "1 day," "2 days," etc., up to "greater than 2 wk" were given to the subjects for their response. Analysis was by nonparametric ANOVA and appropriate post hoc comparison procedures. Unstable postpolio subjects reported a greater recovery time than either the stable postpolio or control subjects (mean +/- SD of 2.6 +/- 3.0 days, 0.6 +/- 1.0 days, and 0.7 +/- 1.1 days, respectively, P postpolio subjects than stable postpolio or control subjects. The cause for this finding is unknown and requires further investigation.

  11. Spring-mass behavior and electromyographic activity evolution during a cycle-run test to exhaustion in triathletes.

    Science.gov (United States)

    Le Meur, Y; Dorel, S; Rabita, G; Bernard, T; Brisswalter, J; Hausswirth, C

    2012-12-01

    To evaluate spring-mass (SM) behavior and associated electromyographic (EMG) activity during a run to exhaustion following a cycle exercise in trained triathletes. Ten triathletes completed four tests: a cycling test to determine V˙O(2max); a running test to determine the lactate threshold (LT); a 5 min control run at LT (C-Run) followed after a total recovery period by a cycle-to-run session to exhaustion [30 min of cycling at ∼80% V˙O(2max) followed by a run until exhaustion at LT (T-Run)]. SM behavior and EMG signals in nine lower limb muscles were recorded throughout the running sessions. Immediately after cycling, leg stiffness was 12.1% higher than its C-Run value and a concomitant increase of EMG activity of knee extensors was observed during pre-contact. Throughout T-Run, leg stiffness decreased by 7.3%, while knee extensors and ankle flexors activities decreased during pre-contact and braking phases. No significant variations in SM parameters and no significant increase of muscle activity were reported between C-Run and the end of T-Run. SM behavior during the cycle-run test was consistent with EMG activity changes. Cessation of exercise was not associated with significant alterations of stiffness values and EMG activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Impact of human activities on the concentration of indoor air particles in an antarctic research station

    Directory of Open Access Journals (Sweden)

    Erica Coelho Pagel

    Full Text Available Abstract One of the main characteristics of Antarctic buildings is the fact that they are designed mostly with a focus on energy efficiency. Although human activity is a major source of pollution, indoor air quality is not a matter of significant concern during building planning. This study examines the relationship between indoor activities in an Antarctic Research Station and the size distribution of particulate matter. Real-time particle size distribution data is used in conjunction with time-activity data. The activity number ratio is calculated using the mean number of particles found in each size range during each activity divided by the average number of particles found during a period characterized by the absence of human activities. Cooking, the use of cosmetics, waste incineration and exhaust from light vehicles were responsible for significant deterioration of indoor air related to the presence of fine and ultrafine particles. Cleaning, physical exercise and the movement of people were responsible for the emission of coarse particles. This article emphasizes the importance of post-occupancy evaluation of buildings, generating results relevant to the planning and layout of new buildings, especially regarding better indoor air quality.

  13. CD4+ T cells with an activated and exhausted phenotype distinguish immunodeficiency during aviremic HIV-2 infection

    DEFF Research Database (Denmark)

    Buggert, Marcus; Frederiksen, Juliet Wairimu; Lund, Ole

    2016-01-01

    , senescence, and transcription factors were assessed by polychromatic flow cytometry. Multidimensional clustering bioinformatic tools were used to identify CD4+ T cell subpopulations linked to infection type and disease stage. RESULTS: HIV-2-infected individuals had early- and late-differentiated CD4+ T cell...... cells are linked to such outcome. DESIGN: HIV-seronegative (n=25), HIV-1 (n?=?33), HIV-2 (n?=?39, of whom 26 were aviremic), and HIV-1/2 dually (HIV-D) (n?=?13) infected subjects were enrolled from an occupational cohort in Guinea-Bissau. METHODS:: CD4+ T cell differentiation, activation, exhaustion...... clusters with lower activation (CD38+HLA-DR+) and exhaustion (PD-1) than HIV-1 and HIV-D-infected subjects. We also noted that aviremic HIV-2-infected individuals possessed fewer CD4+ T cells with pathological signs compared to other HIV-infected groups. Still, compared to HIV-seronegatives, aviremic HIV-2...

  14. Dispersion of traffic-related exhaust particles near the Berlin urban motorway – estimation of fleet emission factors

    Directory of Open Access Journals (Sweden)

    W. Birmili

    2009-04-01

    Full Text Available Atmospheric particle number size distributions of airborne particles (diameter range 10–500 nm were collected over ten weeks at three sites in the vicinity of the A100 urban motorway in Berlin, Germany. The A100 carries about 180 000 vehicles on a weekday. The roadside particle distributions showed a number maximum between 20 and 60 nm clearly related to the motorway emissions. The average total number concentration at roadside was 28 000 cm−3 with a total range of 1200–168 000 cm−3. At distances of 80 and 400 m from the motorway the concentrations decreased to mean levels of 11 000 and 9000 cm−3, respectively. An obstacle-resolving dispersion model was applied to simulate the 3-D flow field and traffic tracer transport in the urban environment around the motorway. By inverse modelling, vehicle emission factors were derived that are representative of a fleet with a relative share of 6% lorry-like vehicles, and driving at a speed of 80 km h−1. Three different calculation approaches were compared, which differ in the choice of the experimental winds driving the flow simulation. The average emission factor per vehicle was 2.1 (±0.2 · 1014 km−1 for particle number and 0.077 (±0.01 · 1014 cm3 km−1 for particle volume. Regression analysis suggested that lorry-like vehicles emit 123 (±28 times more particle number than passenger car-like vehicles, and lorry-like vehicles account for about 91% of particulate number emissions on weekdays. Our work highlights the increasing applicability of 3-D flow models in urban microscale environments and their usefulness for determining traffic emission factors.

  15. Glycogenin activity and mRNA expression in response to volitional exhaustion in human skeletal muscle

    DEFF Research Database (Denmark)

    Shearer, Jane; Graham, Terry E.; Battram, Danielle S.

    2005-01-01

    ) exercised to volitional exhaustion (Exh) on a cycle ergometer at 75% maximal O2 uptake. Muscle biopsies were obtained at rest, 30 min, and Exh (99 ± 10 min). At rest, total glycogen concentration was 497 ± 41 and declined to 378 ± 51 mmol glucosyl units/kg dry wt following 30 min of exercise (P

  16. Major grass pollen allergen Lol p 1 binds to diesel exhaust particles: implications for asthma and air pollution.

    Science.gov (United States)

    Knox, R B; Suphioglu, C; Taylor, P; Desai, R; Watson, H C; Peng, J L; Bursill, L A

    1997-03-01

    Grass pollen allergens are known to be present in the atmosphere in a range of particle sizes from whole pollen grains (approx. 20 to 55 microns in diameter) to smaller size fractions Lol p 1, immunogold labelling with specific monoclonal antibodies and a high voltage transmission electron-microscopic imaging technique. DECP are visualized as small carbon spheres, each 30-60 nm in diameter, forming fractal aggregates about 1-2 microns in diameter. Here we test our hypothesis and show by in vitro experiments that the major grass pollen allergen, Lol p 1, binds to one defined class of fine particles, DECP. DECP are in the respirable size range, can bind to the major grass pollen allergen Lol p 1 under in vitro conditions and represent a possible mechanism by which allergens can become concentrated in polluted air and thus trigger attacks of asthma.

  17. Toluene vapor capture by activated carbon particles in a dual gas-solid cyclone system.

    Science.gov (United States)

    Lim, Yun Hui; Ngo, Khanh Quoc; Park, Young Koo; Jo, Young Min

    2012-08-01

    Capturing of odorous compounds such as toluene vapor by a particulate-activated carbon adsorbent was investigated in a gas-solid cyclone, which is one type of mobile beds. The test cyclone was early modified with the post cyclone (PoC) and a spiral flow guide to the vortex finder. The proposed process may contribute to the reduction of gases and dust from industrial exhausts, especially when dealing with a low concentration of odorous elements and a large volume ofdust flow. In this device, the toluene capturing efficiency at a 400 ppm concentration rose up to 77.4% when using activated carbon (AC) particles with a median size of 27.03 microm. A maximum 96% of AC particles could be collected for reuse depending on the size and flow rate. The AC regenerated via thermal treatment showed an adsorption potential up to 66.7% throughout repeated tests.

  18. Inhibitory receptor expression depends more dominantly on differentiation and activation than exhaustion of human CD8 T cells

    Directory of Open Access Journals (Sweden)

    Amandine eLegat

    2013-12-01

    Full Text Available Under conditions of chronic antigen stimulation, such as persistent viral infection and cancer, CD8 T cells may diminish effector function, which has been termed exhaustion. Expression of inhibitory Receptors (iRs is often regarded as a hallmark of exhaustion. Here we studied the expression of eight different iRs by CD8 T cells of healthy humans, including CTLA-4, PD1, TIM3, LAG3, 2B4, BTLA, CD160 and KLRG-1. We show that many iRs are expressed upon activation, and with progressive differentiation to effector cells, even in absence of long-term (chronic antigenic stimulation. In particular, we evaluated the direct relationship between iR expression and functionality in CD8 T cells by using anti-CD3 and anti-CD28 stimulation to stimulate all cells and differentiation subsets. We observed a striking upregulation of certain iRs following the cytokine production wave, in agreement with the notion that iRs function as a negative feedback mechanism. Intriguingly, we found no major impairment of cytokine production in cells positive for a broad array of iRs, as previously shown for PD1 in healthy donors. Rather, the expression of the various iRs strongly correlated with T cell differentiation or activation states, or both. Furthermore, we analyzed CD8 T cells from lymph nodes (LNs of melanoma patients. Interestingly, we found altered iR expression and lower cytokine production by T cells from metastatic LNs, but also from non-metastatic LNs, likely due to mechanisms which are not related to exhaustion. Together, our data shows that expression of iRs per se does not mark dysfunctional cells, but is rather tightly linked to activation and differentiation. This study highlights the importance of considering the status of activation and differentiation for the study and the clinical monitoring of CD8 T cells.

  19. Revision of the DELFIC Particle Activity Module

    Energy Technology Data Exchange (ETDEWEB)

    Hooper, David A [ORNL; Jodoin, Vincent J [ORNL

    2010-09-01

    The Defense Land Fallout Interpretive Code (DELFIC) was originally released in 1968 as a tool for modeling fallout patterns and for predicting exposure rates. Despite the continual advancement of knowledge of fission yields, decay behavior of fission products, and biological dosimetry, the decay data and logic of DELFIC have remained mostly unchanged since inception. Additionally, previous code revisions caused a loss of conservation of radioactive nuclides. In this report, a new revision of the decay database and the Particle Activity Module is introduced and explained. The database upgrades discussed are replacement of the fission yields with ENDF/B-VII data as formatted in the Oak Ridge Isotope Generation (ORIGEN) code, revised decay constants, revised exposure rate multipliers, revised decay modes and branching ratios, and revised boiling point data. Included decay logic upgrades represent a correction of a flaw in the treatment of the fission yields, extension of the logic to include more complex decay modes, conservation of nuclides (including stable nuclides) at all times, and conversion of key variables to double precision for nuclide conservation. Finally, recommended future work is discussed with an emphasis on completion of the overall radiation physics upgrade, particularly for dosimetry, induced activity, decay of the actinides, and fractionation.

  20. The influence of diesel-truck exhaust particles on the kinetics of the atmospheric oxidation of dissolved sulfur dioxide by oxygen.

    Science.gov (United States)

    Meena, Vimlesh Kumar; Dhayal, Yogpal; Saxena, Deepa; Rani, Ashu; Chandel, C P Singh; Gupta, K S

    2016-09-01

    The automobile exhausts are one of the major sources of particulate matter in urban areas and these particles are known to influence the atmospheric chemistry in a variety of ways. Because of this, the oxidation of dissolved sulfur dioxide by oxygen was studied in aqueous suspensions of particulates, obtained by scraping the particles deposited inside a diesel truck exhaust pipe (DEP). A variation in pH showed the rate to increase with increase in pH from 5.22 to about ∼6.3 and to decrease thereafter becoming very slow at pH = 8.2. In acetate-buffered medium, the reaction rate was higher than the rate in unbuffered medium at the same pH. Further, the rate was found to be higher in suspension than in the leachate under otherwise identical conditions. And, the reaction rate in the blank reaction was the slowest. This appears to be due to catalysis by leached metal ions in leachate and due to catalysis by leached metal ions and particulate surface both in suspensions. The kinetics of dissolved SO2 oxidation in acetate-buffered medium as well as in unbuffered medium at pH = 5.22 were defined by rate law: k obs  = k 0 + k cat [DEP], where k obs and k 0 are observed rate constants in the presence and the absence of DEP and k cat is the rate constant for DEP-catalyzed pathway. At pH = 8.2, the reaction rate was strongly inhibited by DEP in buffered and unbuffered media. Results suggest that the DEP would have an inhibiting effect in those areas where rainwater pH is 7 or more. These results at high pH are of particular significance to the Indian subcontinent, because of high rainwater pH. Conversely, it indicates the DEP to retard the oxidation of dissolved SO2 and control rainwater acidification.

  1. Dynamics of Deformable Active Particles under External Flow Field

    Science.gov (United States)

    Tarama, Mitsusuke

    2017-10-01

    In most practical situations, active particles are affected by their environment, for example, by a chemical concentration gradient, light intensity, gravity, or confinement. In particular, the effect of an external flow field is important for particles swimming in a solvent fluid. For deformable active particles such as self-propelled liquid droplets and active vesicles, as well as microorganisms such as euglenas and neutrophils, a general description has been developed by focusing on shape deformation. In this review, we present our recent studies concerning the dynamics of a single active deformable particle under an external flow field. First, a set of model equations of active deformable particles including the effect of a general external flow is introduced. Then, the dynamics under two specific flow profiles is discussed: a linear shear flow, as the simplest example, and a swirl flow. In the latter case, the scattering dynamics of the active deformable particles by the swirl flow is also considered.

  2. On the effects of organic matter and sulphur-containing compounds on the CCN activation of combustion particles

    Directory of Open Access Journals (Sweden)

    A. Petzold

    2005-01-01

    Full Text Available The European PartEmis project (Measurement and prediction of emissions of aerosols and gaseous precursors from gas turbine engines was focussed on the characterisation and quantification of exhaust emissions from a gas turbine engine. The combustion aerosol characterisation included on-line measurements of mass and number concentration, size distribution, mixing state, thermal stability of internally mixed particles, hygroscopicity, cloud condensation nuclei (CCN activation potential, and off-line analysis of chemical composition. Based on this extensive data set, the role of sulphuric acid coating and of the organic fraction of the combustion particles for the CCN activation was investigated. Modelling of CCN activation was conducted using microphysical and chemical properties obtained from the measurements as input data. Coating the combustion particles with water-soluble sulphuric acid, increases the potential CCN activation, or lowers the activation diameter, respectively. The adaptation of a Köhler model to the experimental data yielded coatings from 0.1 to 3 vol-% of water-soluble matter, which corresponds to an increase in the fraction of CCN-activated combustion particles from ≤10−4 to ≌10−2 at a water vapour saturation ratio Sw=1.006. Additional particle coating by coagulation of combustion particles and aqueous sulphuric acid particles formed by nucleation further reduces the CCN activation diameter. In contrast, particles containing a large fraction of non-volatile organic compounds grow significantly less at high relative humidity than particles with a lower content of non-volatile OC. The resulting reduction in the potential CCN activation with an increasing fraction of non-volatile OC becomes visible as a trend in the experimental data. While a coating of water-soluble sulphuric acid increases the potential CCN activation, or lowers the activation diameter, respectively, the non-volatile organic compounds, mainly found at

  3. Sedimentation and polar order of active bottom-heavy particles.

    Science.gov (United States)

    Wolff, Katrin; Hahn, Aljoscha M; Stark, Holger

    2013-04-01

    Self-propelled particles in an external gravitational field have been shown to display both an increased sedimentation length and polar order even without particle interactions. Here, we investigate self-propelled particles which additionally are bottom-heavy, that is they feel a torque aligning them to swim against the gravitational field. For bottom-heavy particles the gravitational field has the two opposite effects of i) sedimentation and ii) upward alignment of the particles' swimming direction. We perform a multipole expansion of the one-particle distribution of non-interacting particles with respect to orientation and derive expressions for sedimentation length and mean particle orientation which we check against Brownian Dynamics simulations. For large strength of gravity or small particle speeds and aligning torque, we observe sedimentation with increased sedimentation length compared with passive colloids but also active colloids without bottom-heaviness. Increasing, for example, swimming speed the sedimentation profile is inverted and the particles swim towards the top wall of the enclosing box. We find maximal orientational order at intermediate swimming speeds for both cases of particles with bottom-heaviness and those without. Ordering unsurprisingly is increased for the bottom-heavy particles, but this difference disappears at higher levels of activity and for very high activities ordering goes to zero in both cases.

  4. Biodiesel exhaust-induced cytotoxicity and proinflammatory mediator production in human airway epithelial cells.

    Science.gov (United States)

    Mullins, Benjamin J; Kicic, Anthony; Ling, Kak-Ming; Mead-Hunter, Ryan; Larcombe, Alexander N

    2016-01-01

    Increasing use of biodiesel has prompted research into the potential health effects of biodiesel exhaust exposure. Few studies directly compare the health consequences of mineral diesel, biodiesel, or blend exhaust exposures. Here, we exposed human epithelial cell cultures to diluted exhaust generated by the combustion of Australian ultralow-sulfur-diesel (ULSD), unprocessed canola oil, 100% canola biodiesel (B100), and a blend of 20% canola biodiesel mixed with 80% ULSD. The physicochemical characteristics of the exhaust were assessed and we compared cellular viability, apoptosis, and levels of interleukin (IL)-6, IL-8, and Regulated on Activation, Normal T cell Expressed and Secreted (RANTES) in exposed cultured cells. Different fuel types produced significantly different amounts of exhaust gases and different particle characteristics. All exposures resulted in significant apoptosis and loss of viability when compared with control, with an increasing proportion of biodiesel being correlated with a decrease in viability. In most cases, exposure to exhaust resulted in an increase in mediator production, with the greatest increases most often in response to B100. Exposure to pure canola oil (PCO) exhaust did not increase mediator production, but resulted in a significant decrease in IL-8 and RANTES in some cases. Our results show that canola biodiesel exhaust exposure elicits inflammation and reduces viability of human epithelial cell cultures in vitro when compared with ULSD exhaust exposure. This may be related to an increase in particle surface area and number in B100 exhaust when compared with ULSD exhaust. Exposure to PCO exhaust elicited the greatest loss of cellular viability, but virtually no inflammatory response, likely due to an overall increase in average particle size. © 2014 Wiley Periodicals, Inc.

  5. In utero exposure of mice to diesel exhaust particles affects spatial learning and memory with reduced N-methyl-D-aspartate receptor expression in the hippocampus of male offspring.

    Science.gov (United States)

    Yokota, Satoshi; Sato, Akira; Umezawa, Masakazu; Oshio, Shigeru; Takeda, Ken

    2015-09-01

    Diesel exhaust consists of diesel exhaust particles (DEPs) and gaseous compounds. Previous studies reported that in utero exposure to diesel exhaust affects the central nervous system. However, there was no clear evidence that these effects were caused by diesel exhaust particles themselves, gaseous compounds, or both. Here, we explored the effects of in utero exposure to DEPs on learning and memory in male ICR mice. DEP solutions were administered subcutaneously to pregnant ICR mice at a dose of 0 or 200 μg/kg body weight on gestation days 6, 9, 12, 15, and 18. We examined learning and memory in 9-to-10-week-old male offspring using the Morris water maze test and passive avoidance test. Immediately after the behavioral tests, hippocampi were isolated. Hippocampal N-methyl-D-aspartate receptor (NR) expression was also measured by quantitative RT-PCR analysis. Mice exposed to DEPs in utero showed deficits in the Morris water maze test, but their performance was not significantly different from that of control mice in the passive avoidance test. In addition, DEP-exposed mice exhibited decreased hippocampal NR2A expression. The present results indicate that maternal DEP exposure disrupts learning and memory in male offspring, which is associated with reduced hippocampal NR2A expression. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Increased PIO2 at Exhaustion in Hypoxia Enhances Muscle Activation and Swiftly Relieves Fatigue: A Placebo or a PIO2 Dependent Effect?

    Science.gov (United States)

    Torres-Peralta, Rafael; Losa-Reyna, José; Morales-Alamo, David; González-Izal, Miriam; Pérez-Suárez, Ismael; Ponce-González, Jesús G; Izquierdo, Mikel; Calbet, José A L

    2016-01-01

    To determine the level of hypoxia from which muscle activation (MA) is reduced during incremental exercise to exhaustion (IE), and the role played by PIO2 in this process, ten volunteers (21 ± 2 years) performed four IE in severe acute hypoxia (SAH) (PIO2 = 73 mmHg). Upon exhaustion, subjects were asked to continue exercising while the breathing gas mixture was swiftly changed to a placebo (73 mmHg) or to a higher PIO2 (82, 92, 99, and 142 mmHg), and the IE continued until a new exhaustion. At the second exhaustion, the breathing gas was changed to room air (normoxia) and the IE continued until the final exhaustion. MA, as reflected by the vastus medialis (VM) and lateralis (VL) EMG raw and normalized root mean square (RMSraw, and RMSNz, respectively), normalized total activation index (TAINz), and burst duration were 8-20% lower at exhaustion in SAH than in normoxia (P exhaustion reduces fatigue and allows for the continuation of exercise in moderate and SAH, regardless of the effects of PIO2 on MA. At task failure, MA is increased during the first 10 s of increased PIO2 when the IE is performed at a PIO2 close to 73 mmHg and the PIO2 is increased to 92 mmHg or higher. Overall, these findings indicate that one of the central mechanisms by which severe hypoxia may cause central fatigue and task failure is by reducing the capacity for reaching the appropriate level of MA to sustain the task. The fact that at exhaustion in severe hypoxia the exercise was continued with the placebo-gas mixture demonstrates that this central mechanism has a cognitive component.

  7. Comparison of Blood Lactate Elimination in Individuals With Paraplegia and Able-Bodied Individuals During Active Recovery From Exhaustive Exercise

    Science.gov (United States)

    Leicht, Christof; Perret, Claudio

    2008-01-01

    Background/Objective: The aim of the present study was to compare blood lactate elimination between individuals with paraplegia (P) and able-bodied (AB) individuals after strenuous arm exercise. Methods: Eight P and 8 AB men (matched for age, height, and weight) participated in this study. Average weekly arm-training volume for P participants (eg, hand bike, wheelchair basketball) and AB participants (eg, swimming, rowing, cross-country skiing) was 4.1 ± 1.6 vs 2.8 ± 0.8 h. A maximal-arm-cranking intensity-graded exercise test to volitional exhaustion was performed by all test participants. Immediately after the exercise test, the participants performed arm cranking for another 30 minutes at a workload of one third of the maximally achieved power output. During this active recovery, mixed-capillary blood samples were taken for lactate analysis. Results: The lactate accumulation constant was significantly higher for P individuals, whereas the lactate elimination constant showed no significant difference between the two groups. Conclusions: Individuals with paraplegia seem to have no disadvantages in lactate elimination after exhaustive arm exercise compared with able-bodied individuals. PMID:18533413

  8. Role of TLR4 in olfactory-based spatial learning activity of neonatal mice after developmental exposure to diesel exhaust origin secondary organic aerosol.

    Science.gov (United States)

    Nway, Nay Chi; Fujitani, Yuji; Hirano, Seishiro; Mar, Ohn; Win-Shwe, Tin-Tin

    2017-12-01

    Exposure to ambient air pollutants has been reported to have various adverse health impacts. Ambient particulate matter comprises primary particles released directly via engine exhaust and secondary organic aerosols (SOAs) formed from oxidative reactions of the ultrafine particle fraction of diesel exhaust (DE). Toll-like receptor 4 (TLR4) is well known to initiate the inflammatory cascade in the central nervous system. However, whether and how DE and DE-SOA exposure influences TLR4 signaling in the immature brain remains unclear. We attempted to evaluate the roles of TLR-4, inflammatory mediators and microglial markers in the impaired spatial learning ability of neonatal mice exposed to DE and DE-SOAs. Pregnant C3H/HeN (TLR4-intact) and C3H/HeJ (TLR4- mutated) mice were exposed to clean air, DE or DE-SOA from gestational day 14 to postnatal day (PND) 10 (5h/day for 5days) in exposure chambers. PND11 neonatal mice were examined for their performance in the olfactory-based spatial learning test. After the spatial learning test, the hippocampi of the mice were removed and real-time RT-PCR analysis was performed to examine the neurological and immunological markers. Both male and female C3H/HeN and C3H/HeJ neonatal mice exposed to DE and DE-SOAs showed poor performance in the test phase of spatial learning as compared to the mice exposed to clean air. However, this spatial learning deficit was prominent in C3H/HeJ neonatal mice. In the neonatal C3H/HeN male mice exposed to DE and DE-SOAs, the mRNA expression levels of the NMDA receptor subunits (NR1, NR2B), proinflammatory cytokines, tumor necrosis factor-α and cyclooxygenase-2, oxidative stress marker, heme oxygenase-1, and microglial marker, Iba1, in the hippocampus were significantly increased, but these changes were not observed in female mice. Our findings indicate that activation of the neuroimmune system and TLR4 signaling may possibly be involved in environmental pollutant-induced spatial learning impairment

  9. Hysteretic dynamics of active particles in a periodic orienting field.

    Science.gov (United States)

    Romensky, Maksym; Scholz, Dimitri; Lobaskin, Vladimir

    2015-07-06

    Active motion of living organisms and artificial self-propelling particles has been an area of intense research at the interface of biology, chemistry and physics. Significant progress in understanding these phenomena has been related to the observation that dynamic self-organization in active systems has much in common with ordering in equilibrium condensed matter such as spontaneous magnetization in ferromagnets. The velocities of active particles may behave similar to magnetic dipoles and develop global alignment, although interactions between the individuals might be completely different. In this work, we show that the dynamics of active particles in external fields can also be described in a way that resembles equilibrium condensed matter. It follows simple general laws, which are independent of the microscopic details of the system. The dynamics is revealed through hysteresis of the mean velocity of active particles subjected to a periodic orienting field. The hysteresis is measured in computer simulations and experiments on unicellular organisms. We find that the ability of the particles to follow the field scales with the ratio of the field variation period to the particles' orientational relaxation time, which, in turn, is related to the particle self-propulsion power and the energy dissipation rate. The collective behaviour of the particles due to aligning interactions manifests itself at low frequencies via increased persistence of the swarm motion when compared with motion of an individual. By contrast, at high field frequencies, the active group fails to develop the alignment and tends to behave like a set of independent individuals even in the presence of interactions. We also report on asymptotic laws for the hysteretic dynamics of active particles, which resemble those in magnetic systems. The generality of the assumptions in the underlying model suggests that the observed laws might apply to a variety of dynamic phenomena from the motion of

  10. Review of the stack discharge active particle contamination problem

    Energy Technology Data Exchange (ETDEWEB)

    Parker, H M

    1948-03-22

    Quantities of the order of ten million to 100 million radioactive particles per month were emitted from the stacks over a period of several months. High activity in the range 0.1 to 3..mu..c was probably confined to large carrier particles of corrosion debris from iron ductwork in the separations plant ventilation air system. This report discusses chemical, physical and radiochemical properties of the particles, and possible biological and health effects of exposure to them. (ACR)

  11. Rheotaxis of spherical active particles near a planar wall.

    Science.gov (United States)

    Uspal, W E; Popescu, M N; Dietrich, S; Tasinkevych, M

    2015-09-07

    For active particles the interplay between the self-generated hydrodynamic flow and an external shear flow, especially near bounding surfaces, can result in a rich behavior of the particles not easily foreseen from the consideration of the active and external driving mechanisms in isolation. For instance, under certain conditions, the particles exhibit "rheotaxis", i.e., they align their direction of motion with the plane of shear spanned by the direction of the flow and the normal of the bounding surface and move with or against the flow. To date, studies of rheotaxis have focused on elongated particles (e.g., spermatozoa), for which rheotaxis can be understood intuitively in terms of a "weather vane" mechanism. Here we investigate the possibility that spherical active particles, for which the "weather vane" mechanism is excluded due to the symmetry of the shape, may nevertheless exhibit rheotaxis. Combining analytical and numerical calculations, we show that, for a broad class of spherical active particles, rheotactic behavior may emerge via a mechanism which involves "self-trapping" near a hard wall owing to the active propulsion of the particles, combined with their rotation, alignment, and "locking" of the direction of motion into the shear plane. In this state, the particles move solely up- or downstream at a steady height and orientation.

  12. Convective self-propulsion of chemically active particles

    Science.gov (United States)

    Shklyaev, Oleg; Shum, Henry; Balazs, Anna

    2016-11-01

    A mechanism of particle self-propulsion activated by transduction of chemical energy into convective motion of fluid that drags microscale particles is proposed. The convection is generated by an active spherical particle located on the bottom of a microchannel and coated with a catalyst that decomposes reagent dissolved in the solution into less dense products and gives rise to a buoyancy force. The symmetry of the flow generated around the active particle can be broken if a passive spherical particle, which does not produce the flow, is present in the vicinity of the first one. The generated flow drags the passive particle toward the active one along the bottom wall until they form a dimer. The resulting asymmetric fluid flow, which is generated by only one of the particles, imposes a different drag on the different sides on the dimer. The net force causes the dimer to translate along the bottom wall. By varying numbers of active and passive particles, as well as their positions within a group, one can control the structure of the generated convective flow and, therefore, design clusters with different mobile properties. The proposed mechanism can be harnessed to transport cargo in microchannels.

  13. Controlled exposure to diesel exhaust and traffic noise--Effects on oxidative stress and activation in mononuclear blood cells.

    Science.gov (United States)

    Hemmingsen, Jette Gjerke; Møller, Peter; Jantzen, Kim; Jönsson, Bo A G; Albin, Maria; Wierzbicka, Aneta; Gudmundsson, Anders; Loft, Steffen; Rissler, Jenny

    2015-05-01

    Particulate air pollution increases risk of cancer and cardiopulmonary disease, partly through oxidative stress. Traffic-related noise increases risk of cardiovascular disease and may cause oxidative stress. In this controlled random sequence study, 18 healthy subjects were exposed for 3h to diesel exhaust (DE) at 276 μg/m(3) from a passenger car or filtered air, with co-exposure to traffic noise at 48 or 75 dB(A). Gene expression markers of inflammation, (interleukin-8 and tumor necrosis factor), oxidative stress (heme oxygenase (decycling-1)) and DNA repair (8-oxoguanine DNA glycosylase (OGG1)) were unaltered in peripheral blood mononuclear cells (PBMCs). No significant differences in DNA damage levels, measured by the comet assay, were observed after DE exposure, whereas exposure to high noise levels was associated with significantly increased levels of hOGG1-sensitive sites in PBMCs. Urinary levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine were unaltered. In auxiliary ex vivo experiments whole blood was incubated with particles from the exposure chamber for 3h without effects on DNA damage in PBMCs or intracellular reactive oxygen species production and expression of CD11b and CD62L adhesion molecules in leukocyte subtypes. 3-h exposure to DE caused no genotoxicity, oxidative stress or inflammation in PBMCs, whereas exposure to noise might cause oxidatively damaged DNA. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  14. Whole and particle-free diesel exhausts differentially affect cardiac electrophysiology, blood pressure, and autonomic balance in heart failure-prone rats

    Science.gov (United States)

    Epidemiologic studies strongly link short-term exposures to vehicular traffic and particulate matter (PM) air pollution with adverse cardiovascular events, especially in those with preexisting cardiovascular disease. Diesel engine exhaust (DE) is a key contributor to urban ambien...

  15. Influence of physical and chemical characteristics of diesel fuels and exhaust emissions on biological effects of particle extracts: A multivariant statistical analysis of ten diesel fuels

    Energy Technology Data Exchange (ETDEWEB)

    Sjoegren, M.; Rannug, U.; Li, Hang [Stockholm Univ. (Sweden)] [and others

    1996-01-01

    This study investigated the biological effects of particulates found in exhaust gases from the combustion of diesel fuel. Models are described for correlating the biological effects to the physical and chemical properties of the fuel.

  16. Stacked dipole line source excitation of active nano-particles

    DEFF Research Database (Denmark)

    Arslanagic, Samel

    This work investigates electromagnetic properties of cylindrical active coated nano-particles excited by a stac- ked electric dipole line source. The nano-particles consist of a silica nano-core, layered by silver, gold, or copper nano-shell. Attention is devoted to the influence of the source...... location and dipole orientation, the gain constant, and the nano-particle material composition on the electromagnetic field distributions and radiated powers. The results are contrasted to those for the magnetic line source illumination of the nano-particles....

  17. Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy

    Directory of Open Access Journals (Sweden)

    Chaoqi Shen

    2016-12-01

    Full Text Available The kinetics of hydrogen absorption/desorption can be improved by decreasing particle size down to a few nanometres. However, the associated evolution of activation energy remains unclear. In an attempt to clarify such an evolution with respect to particle size, we electrochemically deposited Mg nanoparticles on a catalytic nickel and noncatalytic titanium substrate. At a short deposition time of 1 h, magnesium particles with a size of 68 ± 11 nm could be formed on the nickel substrate, whereas longer deposition times led to much larger particles of 421 ± 70 nm. Evaluation of the hydrogen desorption properties of the deposited magnesium nanoparticles confirmed the effectiveness of the nickel substrate in facilitating the recombination of hydrogen, but also a significant decrease in activation energy from 56.1 to 37.8 kJ·mol−1 H2 as particle size decreased from 421 ± 70 to 68 ± 11 nm. Hence, the activation energy was found to be intrinsically linked to magnesium particle size. Such a reduction in activation energy was associated with the decrease of path lengths for hydrogen diffusion at the desorbing MgH2/Mg interface. Further reduction in particle size to a few nanometres to remove any barrier for hydrogen diffusion would then leave the single nucleation and growth of the magnesium phase as the only remaining rate-limiting step, assuming that the magnesium surface can effectively catalyse the dissociation/recombination of hydrogen.

  18. Increased PIO2 at exhaustion in hypoxia enhances muscle activation and swiftly relieves fatigue: a placebo or a PIO2 dependent effect?

    Directory of Open Access Journals (Sweden)

    Rafael Torres-Peralta

    2016-08-01

    Full Text Available To determine the level of hypoxia from which muscle activation (MA is reduced during incremental exercise to exhaustion (IE, and the role played by PIO2 in this process, ten volunteers (21±2 years performed four IE in severe acute hypoxia (SAH (PIO2=73 mmHg. Upon exhaustion, subjects were asked to continue exercising while the breathing gas mixture was swiftly changed to a placebo (73 mmHg or to a higher PIO2 (82, 92, 99, 142 mmHg, and the IE continued until a new exhaustion. At the second exhaustion, the breathing gas was changed to room air (normoxia and the IE continued until the final exhaustion. MA, as reflected by the vastus medialis (VM and lateralis (VL EMG raw and normalized root mean square (RMSraw, RMSNz, respectively, normalized total activation index (TAINz, and burst duration were 8-20 % lower at exhaustion in SAH than in normoxia (P<0.05. The switch to a placebo or higher PIO2 allowed for the continuation of exercise in all instances. RMSraw, RMSNz and TAINz were increased by 5-11% when the PIO2 was raised from 73 to 92 or 99 mmHg, and VL and VM averaged RMSraw by 7% when the PIO2 was elevated from 73 to 142 mmHg (P<0.05. The increase of VM-VL average RMSraw was linearly related to the increase in PIO2, during the transition from SAH to higher PIO2 (R2=0.99, P<0.5. In conclusion, increased PIO2 at exhaustion reduces fatigue and allows for the continuation of exercise in moderate and SAH, regardless of the effects of PIO2 on MA. At task failure, MA is increased during the first 10 s of increased PIO2 when the IE is performed at a PIO2 close to 73 mmHg and the PIO2 is increased to 92 mmHg or higher. Overall, these findings indicate that one of the central mechanisms by which severe hypoxia may cause central fatigue and task failure is by reducing the capacity for reaching the appropriate level of muscle activation to sustain the task. The fact that at exhaustion in severe hypoxia the exercise was continued with the placebo

  19. BEHAVIORAL ACTIVITY OF RATS IN THE «OPEN FIELD» AFTER THE LIGHT AND DARK DEPRIVATION AND PHYSICAL EXHAUSTION

    Directory of Open Access Journals (Sweden)

    A. A. Gostyukhina

    2016-01-01

    Full Text Available Aim. As is known, various stressful loads and their combination lead to unequal direction and degree of psychological and emotional instability. In this regard, one of the pressing issues becomes regulation and correction of psycho-emotional conditions of the person in the complicated conditions of activity, such as athletes during training and competition. To develop appropriate stress-corrective programs should their experimental validation. Therefore, the aim of this study was to investigate the behavioral activity of rats in the “open field” after dark or light deprivation and physical fatigue.Materials and methods. The experimental study was performed on the 40 adult male rats “Wistar”. The experimental groups for 10 days were kept in an artificial bright light (150 lx or darkness (2–3 lx for the induction of desynchronozes. Method of forced swimming until complete exhaustion was chosen for the model of physical fatigue. The animals in all groups evaluated behavioral activity in the “open field” in daylight conditions after 24 h after swim test.Results. It was established that in the control group in the terms of natural lighting day after 5 days of daily physical activity occurred depression of the active-search behavior in the “open field”. It was expressed in reducing the number of crossed squares and vertical struts in comparison to intact animals receiving no load. In the groups of animals, which kept in a dark or light deprivation until the presentation of the swim test there was an increase in passive-defensive behavior in the “open field”, which was reflected in an increase in acts of grooming and defecation. 

  20. Soot Aerosol Particles as Cloud Condensation Nuclei: from Ice Nucleation Activity to Ice Crystal Morphology

    Science.gov (United States)

    Pirim, Claire; Ikhenazene, Raouf; Ortega, Isamel Kenneth; Carpentier, Yvain; Focsa, Cristian; Chazallon, Bertrand; Ouf, François-Xavier

    2016-04-01

    Emissions of solid-state particles (soot) from engine exhausts due to incomplete fuel combustion is considered to influence ice and liquid water cloud droplet activation [1]. The activity of these aerosols would originate from their ability to be important centers of ice-particle nucleation, as they would promote ice formation above water homogeneous freezing point. Soot particles are reported to be generally worse ice nuclei than mineral dust because they activate nucleation at higher ice-supersaturations for deposition nucleation and at lower temperatures for immersion freezing than ratios usually expected for homogeneous nucleation [2]. In fact, there are still numerous opened questions as to whether and how soot's physico-chemical properties (structure, morphology and chemical composition) can influence their nucleation ability. Therefore, systematic investigations of soot aerosol nucleation activity via one specific nucleation mode, here deposition nucleation, combined with thorough structural and compositional analyzes are needed in order to establish any association between the particles' activity and their physico-chemical properties. In addition, since the morphology of the ice crystals can influence their radiative properties [3], we investigated their morphology as they grow over both soot and pristine substrates at different temperatures and humidity ratios. In the present work, Combustion Aerosol STandart soot samples were produced from propane using various experimental conditions. Their nucleation activity was studied in deposition mode (from water vapor), and monitored using a temperature-controlled reactor in which the sample's relative humidity is precisely measured with a cryo-hygrometer. Formation of water/ice onto the particles is followed both optically and spectroscopically, using a microscope coupled to a Raman spectrometer. Vibrational signatures of hydroxyls (O-H) emerge when the particle becomes hydrated and are used to characterize ice

  1. Active Exhaust Silencing Systen For the Management of Auxillary Power Unit Sound Signatures

    Science.gov (United States)

    2014-08-01

    a noise generation device, usually a speaker. One of the most popular adaptive algorithms Least Mean Squares ( LMS ) algorithm. The function of the...first section of this paper, the theory of noise cancellation within a duct will be discussed. An ideal noise source will be analyzed, but...recorded data. THEORY OF SOUND CANCELLATION IN A DUCT The goal of an active noise cancellation system is to find a pressure field to be

  2. Self-assembly of active amphiphilic Janus particles

    Science.gov (United States)

    Mallory, S. A.; Alarcon, F.; Cacciuto, A.; Valeriani, C.

    2017-12-01

    In this article, we study the phenomenology of a two dimensional dilute suspension of active amphiphilic Janus particles. We analyze how the morphology of the aggregates emerging from their self-assembly depends on the strength and the direction of the active forces. We systematically explore and contrast the phenomenologies resulting from particles with a range of attractive patch coverages. Finally, we illustrate how the geometry of the colloids and the directionality of their interactions can be used to control the physical properties of the assembled active aggregates and suggest possible strategies to exploit self-propulsion as a tunable driving force for self-assembly.

  3. CD40 activation rescues antiviral CD8⁺ T cells from PD-1-mediated exhaustion.

    Directory of Open Access Journals (Sweden)

    Masanori Isogawa

    Full Text Available The intrahepatic immune environment is normally biased towards tolerance. Nonetheless, effective antiviral immune responses can be induced against hepatotropic pathogens. To examine the immunological basis of this paradox we studied the ability of hepatocellularly expressed hepatitis B virus (HBV to activate immunologically naïve HBV-specific CD8⁺ T cell receptor (TCR transgenic T cells after adoptive transfer to HBV transgenic mice. Intrahepatic priming triggered vigorous in situ T cell proliferation but failed to induce interferon gamma production or cytolytic effector function. In contrast, the same T cells differentiated into cytolytic effector T cells in HBV transgenic mice if Programmed Death 1 (PD-1 expression was genetically ablated, suggesting that intrahepatic antigen presentation per se triggers negative regulatory signals that prevent the functional differentiation of naïve CD8⁺ T cells. Surprisingly, coadministration of an agonistic anti-CD40 antibody (αCD40 inhibited PD-1 induction and restored T cell effector function, thereby inhibiting viral gene expression and causing a necroinflammatory liver disease. Importantly, the depletion of myeloid dendritic cells (mDCs strongly diminished the αCD40 mediated functional differentiation of HBV-specific CD8⁺ T cells, suggesting that activation of mDCs was responsible for the functional differentiation of HBV-specific CD8⁺ T cells in αCD40 treated animals. These results demonstrate that antigen-specific, PD-1-mediated CD8⁺ T cell exhaustion can be rescued by CD40-mediated mDC-activation.

  4. Comparison Between Dielectric Barrier Discharge Plasma and Ozone Regenerations of Activated Carbon Exhausted with Pentachlorophenol

    Science.gov (United States)

    Qu, Guangzhou; Liang, Dongli; Qu, Dong; Huang, Yimei; Li, Jie

    2014-06-01

    In this study, two regeneration methods (dielectric barrier discharge (DBD) plasma and ozone (O3) regeneration) of saturated granular activated carbon (GAC) with pentachlorophenol (PCP) were compared. The results show that the two regeneration methods can eliminate contaminants from GAC and recover its adsorption properties to some extent. Comparing the DBD plasma with O3 regeneration, the adsorption rate and the capacity of the GAC samples after DBD plasma regeneration are greater than those after O3 regeneration. O3 regeneration decreases the specific surface area of GAC and increases the acidic surface oxygen groups on the surface of GAC, which causes a decrease in PCP on GAC uptake. With increasing regeneration cycles, the regeneration efficiencies of the two methods decrease, but the decrease in the regeneration efficiencies of GAC after O3 regeneration is very obvious compared with that after DBD plasma regeneration. Furthermore, the equilibrium data were fitted by the Freundlich and Langmuir models using the non-linear regression technique, and all the adsorption equilibrium isotherms fit the Langmuir model fairly well, which demonstrates that the DBD plasma and ozone regeneration processes do not appear to modify the adsorption process, but to shift the equilibrium towards lower adsorption concentrations. Analyses of the weight loss of GAC show that O3 regeneration has a lower weight loss than DBD plasma regeneration.

  5. Atorvastatin reduces T-cell activation and exhaustion among HIV-infected cART-treated suboptimal immune responders in Uganda: a randomised crossover placebo-controlled trial.

    Science.gov (United States)

    Nakanjako, Damalie; Ssinabulya, Isaac; Nabatanzi, Rose; Bayigga, Lois; Kiragga, Agnes; Joloba, Moses; Kaleebu, Pontiano; Kambugu, Andrew D; Kamya, Moses R; Sekaly, Rafick; Elliott, Alison; Mayanja-Kizza, Harriet

    2015-03-01

    T-cell activation independently predicts mortality, poor immune recovery and non-AIDS illnesses during combination antiretroviral therapy (cART). Atorvastatin showed anti-immune activation effects among HIV-infected cART-naïve individuals. We investigated whether adjunct atorvastatin therapy reduces T-cell activation among cART-treated adults with suboptimal immune recovery. A randomised double-blind placebo-controlled crossover trial, of atorvastatin 80 mg daily vs. placebo for 12 weeks, was conducted among individuals with CD4 increase <295 cells/μl after seven years of suppressive cART. Change in T-cell activation (CD3 + CD4 + /CD8 + CD38 + HLADR+) and in T-cell exhaustion (CD3 + CD4 + /CD8 + PD1 + ) was measured using flow cytometry. Thirty patients were randomised, 15 to each arm. Atorvastatin resulted in a 28% greater reduction in CD4 T-cell activation (60% reduction) than placebo (32% reduction); P = 0.001. Atorvastatin also resulted in a 35% greater reduction in CD8-T-cell activation than placebo (49% vs. 14%, P = 0.0009), CD4 T-cell exhaustion (27% vs. 17% in placebo), P = 0.001 and CD8 T-cell exhaustion (27% vs. 16%), P = 0.004. There was no carry-over/period effect. Expected adverse events were comparable in both groups, and no serious adverse events were reported. Atorvastatin reduced T-cell immune activation and exhaustion among cART-treated adults in a Ugandan cohort. Atorvastatin adjunct therapy should be explored as a strategy to improve HIV treatment outcomes among people living with HIV in sub-Saharan Africa. © 2014 John Wiley & Sons Ltd.

  6. Effects of eicosane, a component of nanoparticles in diesel exhaust, on surface activity of pulmonary surfactant monolayers.

    Science.gov (United States)

    Kanno, Sanae; Furuyama, Akiko; Hirano, Seishiro

    2008-11-01

    Recently, it has been reported that n-alkanes are principal components of diesel exhaust nanoparticles. We investigated the effects of n-alkanes on the surface activity of a pulmonary surfactant monolayer using both fresh surfactant isolated from mouse lungs, and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), a major component of lung surfactant. To examine the effect of n-alkanes on the surfactant, we compared surface pressure/trough area isotherm features and topographic images of DPPC in the presence and absence of a specific n-alkane (eicosane, C(20)H(42)) by Langmuir-Wilhelmy methods. The pure DPPC isotherm shows a typical plateau feature at a monolayer collapse pressure of 70 mN/m. The collapse pressure diminishes with increasing concentration of eicosane in DPPC. DPPC monolayers containing eicosane exhibit isotherms with one phase transition, but not the coexistence plateau of a liquid-expanded (LE) and liquid-condensed (LC) phase observed with a pure DPPC monolayer. Atomic force microscopy studies suggest that a DPPC monolayer containing eicosane has the phase transition from LE phase to LC phase and the protrusions are squeezed out from the monolayer, below the phase transition. On the other hand, eicosane changes the isotherm from mouse lung surfactant less dramatically than that of DPPC. The addition of increasing amounts of eicosane to mouse surfactant increases surface compressibility at 30 mN/m during the second compression, suggesting that the deposition of alkane-rich nanoparticles onto pulmonary surfactants may be related to dysfunction of surfactant activity during breathing.

  7. Microfluidic rheology of active particle suspensions: Kinetic theory

    Science.gov (United States)

    Alonso-Matilla, Roberto; Ezhilan, Barath; Saintillan, David

    2016-11-01

    We analyze the effective rheology of a dilute suspension of self-propelled slender particles between two infinite parallel plates in a pressure-driven flow. We use a continuum kinetic model to study the dynamics and transport of particles, where hydrodynamic interactions induced by the swimmers are taken into account. Using finite volume simulations we study how the activity of the swimmer and the external flow modify the rheological properties of the system. Results indicate that at low flow rates, activity decreases the value of the viscosity for pushers and increases its value for pullers. Both effects become weaker with increasing the flow strength due to the alignment of the particles with the flow. In the case of puller particles, shear thinning is observed over the entire range of flow rates. Pusher particles exhibit shear thickening at intermediate flow rates, where passive stresses start dominating over active stresses, reaching a viscosity greater than that of the Newtonian fluid. Finally shear thinning is observed at high flow rates. Both pushers and pullers exhibit a Newtonian plateau at very high flow rates. We demonstrate a good agreement between numerical results and experiments.

  8. CCN activation experiments with adipic acid: effect of particle phase and adipic acid coatings on soluble and insoluble particles

    Directory of Open Access Journals (Sweden)

    S. S. Hings

    2008-07-01

    Full Text Available Slightly soluble atmospherically relevant organic compounds may influence particle CCN activity and therefore cloud formation. Adipic acid is a frequently employed surrogate for such slightly soluble organic materials. The 11 published experimental studies on the CCN activity of adipic acid particles are not consistent with each other nor do they, in most cases, agree with the Köhler theory. The CCN activity of adipic acid aerosol particles was studied over a significantly wider range of conditions than in any previous single study. The work spans the conditions of the previous studies and also provides alternate methods for producing "wet" (deliquesced solution droplets and dry adipic acid particles without the need to produce them by atomization of aqueous solutions. The experiments suggest that the scatter in the previously published CCN measurements is most likely due to the difficulty of producing uncontaminated adipic acid particles by atomization of solutions and possibly also due to uncertainties in the calibration of the instruments. The CCN activation of the small (dm<150 nm initially dry particles is subject to a deliquescence barrier, while for the larger particles the activation follows the Köhler curve. Wet adipic acid particles follow the Köhler curve over the full range of particle diameters studied. In addition, the effect of adipic acid coatings on the CCN activity of both soluble and insoluble particles has also been studied. When a water-soluble core is coated by adipic acid, the CCN-hindering effect of particle phase is eliminated. An adipic acid coating on hydrophobic soot yields a CCN active particle. If the soot particle is relatively small (dcore≤102 nm, the CCN activity of the coated particles approaches the deliquescence line of adipic acid, suggesting that the total size of the particle determines CCN activation and the soot core acts as a scaffold.

  9. Submicrometre particle filtration with a dc activated plasma textile

    Science.gov (United States)

    Rasipuram, S. C.; Wu, M.; Kuznetsov, I. A.; Kuznetsov, A. V.; Levine, J. F.; Jasper, W. J.; Saveliev, A. V.

    2014-01-01

    Plasma textiles are novel fabrics incorporating the advantages of cold plasma and low-cost non-woven or woven textile fabrics. In plasma textiles, electrodes are integrated into the fabric, and a corona discharge is activated within and on the surface of the fabric by applying high voltages above 10 kV between the electrodes. When the plasma textile is activated, submicrometre particles approaching the textile are charged by the deposition of ions and electrons produced by the corona, and then collected by the textile material. A stable plasma discharge was experimentally verified on the surface of the textile that was locally smooth but not rigid. A filtration efficiency close to 100% was observed in experiments conducted on salt particles with diameters ranging from 50 to 300 nm. Unlike conventional fibrous filters, the plasma textile provided uniform filtration in this range, without exhibiting a maximum particle penetration size.

  10. Carbohydrate Mouth Rinse Maintains Muscle Electromyographic Activity and Increases Time to Exhaustion during Moderate but not High-Intensity Cycling Exercise

    Directory of Open Access Journals (Sweden)

    Victor José Bastos-Silva

    2016-03-01

    Full Text Available The aim was to investigate the influence of a carbohydrate (CHO mouth rinse on the vastus lateralis (VL and rectus femoris (RF electromyographic activity (EMG and time to exhaustion (TE during moderate (MIE and high-intensity cycling exercise (HIE. Thirteen participants cycled at 80% of their respiratory compensation point and at 110% of their peak power output to the point of exhaustion. Before the trials and every 15 min during MIE, participants rinsed with the CHO or Placebo (PLA solutions. The root mean square was calculated. CHO had no effect on the TE during HIE (CHO: 177.3 ± 42.2 s; PLA: 163.0 ± 26.7 s, p = 0.10, but the TE was increased during MIE (CHO: 76.6 ± 19.7 min; PLA: 65.4 ± 15.2 min; p = 0.01. The EMG activity in the VL was higher than PLA at 30 min (CHO: 10.5% ± 2.6%; PLA: 7.7% ± 3.3%; p = 0.01 and before exhaustion (CHO: 10.3% ± 2.5%; PLA: 8.0% ± 2.9%; p = 0.01 with CHO rinsing. There was no CHO effect on the EMG activity of RF during MIE or for VL and RF during HIE. CHO mouth rinse maintains EMG activity and enhances performance for MIE but not for HIE.

  11. The Effect of Contrast Temperature Water Therapy on Blood Lactic Acid clearance of male students of Mazandaran University of Science and Technology after exhausting activity

    Directory of Open Access Journals (Sweden)

    Mohammadbagher Forghani

    2015-09-01

    Full Text Available The purpose of this research was the considering of the effect of Contrast Temperature Water Therapy on Blood Lactic Acid clearance of male students of Mazandaran University of Science and Technology after exhausting activity. In this semi-experimental study, 30 male students were randomly chosen and classified between two groups with 15 members, in a design with control group and experimental group, before and two hours after CTWT (experimental group the Bruce test on treadmill was done. The measurement of blood Lactic Acid was done by Lactometer, before and after Bruce tests, and also immediately after CTWT. And then in both groups the results of each test was compared with another test. After that the results between two groups were compared. To analyze the data, the Kolmogorov-Smirnov test, pair T test, and match T test were used in meaning level α≤0/05 for statistical analyze. To summarize, the following findings have been obtained: 1.CTWT reduced the concentration of blood Lactic Acid after exhausting performance significantly; 2. Two hours after recovery, the effect of CTWT on Lactic Acid concentration did not differ from the passive recovery method effect significantly; 3. CTWT did not also have any significant effect on the Lactic Acid accumulation in next exhausting performance; 4. CTWT did not have any significant effect on fluctuations of blood Lactic Acid in next exhausting performance. It is believed that CTWT facilitates recovery by blood circulation, vaso-pumping, hydrostatic pressure due to immersion, relieving of metabolic waste, and central nervous system stimulation. Keywords: Contrast Temperature Water Therapy, exhausting performance, Lactic Acid clearance

  12. Reproducible cavitation activity in water-particle suspensions

    NARCIS (Netherlands)

    Borkent, B.M.; Arora, M.; Ohl, C.D.

    2007-01-01

    The study of cavitation inception in liquids rarely yields reproducible data, unless special control is taken on the cleanliness of the experimental environment. In this paper, an experimental technique is demonstrated which allows repeatable measurements of cavitation activity in liquid-particle

  13. Bacteria associated with granular activated carbon particles in drinking water.

    Science.gov (United States)

    Camper, A K; LeChevallier, M W; Broadaway, S C; McFeters, G A

    1986-09-01

    A sampling protocol was developed to examine particles released from granular activated carbon filter beds. A gauze filter/Swinnex procedure was used to collect carbon fines from 201 granular activated carbon-treated drinking water samples over 12 months. Application of a homogenization procedure (developed previously) indicated that 41.4% of the water samples had heterotrophic plate count bacteria attached to carbon particles. With the enumeration procedures described, heterotrophic plate count bacteria were recovered at an average rate of 8.6 times higher than by conventional analyses. Over 17% of the samples contained carbon particles colonized with coliform bacteria as enumerated with modified most-probable-number and membrane filter techniques. In some instances coliform recoveries were 122 to 1,194 times higher than by standard procedures. Nearly 28% of the coliforms attached to these particles in drinking water exhibited the fecal biotype. Scanning electron micrographs of carbon fines from treated drinking water showed microcolonies of bacteria on particle surfaces. These data indicate that bacteria attached to carbon fines may be an important mechanism by which microorganisms penetrate treatment barriers and enter potable water supplies.

  14. High T-cell immune activation and immune exhaustion among individuals with suboptimal CD4 recovery after 4 years of antiretroviral therapy in an African cohort

    Directory of Open Access Journals (Sweden)

    Colebunders Robert

    2011-02-01

    Full Text Available Abstract Background Antiretroviral therapy (ART partially corrects immune dysfunction associated with HIV infection. The levels of T-cell immune activation and exhaustion after long-term, suppressive ART and their correlation with CD4 T-cell count reconstitution among ART-treated patients in African cohorts have not been extensively evaluated. Methods T-cell activation (CD38+HLA-DR+ and immune exhaustion (PD-1+ were measured in a prospective cohort of patients initiated on ART; 128 patient samples were evaluated and subcategorized by CD4 reconstitution after long-term suppressive treatment: Suboptimal [median CD4 count increase 129 (-43-199 cells/μl], N = 34 ], optimal [282 (200-415 cells/μl, N = 64] and super-optimal [528 (416-878 cells/μl, N = 30]. Results Both CD4+ and CD8 T-cell activation was significantly higher among suboptimal CD4 T-cell responders compared to super-optimal responders. In a multivariate model, CD4+CD38+HLADR+ T-cells were associated with suboptimal CD4 reconstitution [AOR, 5.7 (95% CI, 1.4-23, P = 0.014]. T-cell exhaustion (CD4+PD1+ and CD8+PD1+ was higher among suboptimal relative to optimal (P P = 0.022]. Conclusion T-cell activation and exhaustion persist among HIV-infected patients despite long-term, sustained HIV-RNA viral suppression. These immune abnormalities were associated with suboptimal CD4 reconstitution and their regulation may modify immune recovery among suboptimal responders to ART.

  15. In-situ studies on volatile jet exhaust particle emissions - impacts of fuel sulfur content and environmental conditions on nuclei-mode aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, F.; Baumann, R.; Petzold, A.; Busen, R.; Schulte, P.; Fiebig, M. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany). Inst. fuer Physik der Atmosphaere; Brock, C.A. [Denver Univ., CO (United States). Dept. of Engineering

    2000-02-01

    In-situ measurements of ultrafine aerosol particle emissions were performed at cruise altitudes behind the DLR ATTAS research jet (RR M45H M501 engines) and a B737-300 aircraft (CFM56-3B1 engines). Measurements were made 0.15-20 seconds after emission as the source aircraft burned fuel with sulfur contents (FSC) of 2.6, 56 or 118 mg kg{sup -1}. Particle size distributions of from 3 to 60 nm diameter were determined using CN-counters with varying lower size detection limits. Volatile particle concentrations in the aircraft plumes strongly increased as diameter decreased toward the sizes of large molecular clusters, illustrating that apparent particle emissions are extremely sensitive to the smallest particle size detectable by the instrument used. Environmental conditions and plume age alone could influence the number of detected ultrafine (volatile) aerosols within an order of magnitude, as well. The observed volatile particle emissions decreased nonlinearly as FSC decreased to 60 mg kg{sup -1}, reaching minimum values of about 2 x 10{sup 17} kg{sup -1} and 2 x 10{sup 16} kg{sup -1} for particles >3 nm and >5 nm, respectively. Volatile particle emissions did not change significantly as FSCs were further reduced below 60 mg kg{sup -1}. Volatile particle emissions did not differ significantly between the two studied engine types. In contrast, soot particle emissions from the modern CFM56-3B1 engines were 4-5 times less (4 x 10{sup 14} kg{sup -1}) than from the older RR M45H M501 engines (1.8 x 10{sup 15} kg{sup -1}). Contrail processing has been identified as an efficient sink/quenching parameter for ultrafine particles and reduces the remaining interstitial aerosol by factors 2-10 depending on particle size.

  16. Exposure assessment in studies on health effects of traffic exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Setaelae, S. [Association for the Pulmonary Disabled, Helsinki (Finland); Jaakkola, J.J.K. [Helsinki Univ. (Finland). Dept. of Public Health

    1995-12-31

    A main source of outdoor air pollution is road traffic, which produces a complex mixture of nitrogen oxides, carbon monoxide, volatile hydrocarbons, airborne particles and some other compounds. Traffic exhaust affects also the concentrations of ozone and other photo chemical oxidants. In earlier studies those components have had remarkable health effects. Several studies on occupational exposure to automobile exhaust have been published and several studies have been observed an association between both outdoor and indoor pollutant levels and health outcomes. However, there are only a few epidemiological studies in which traffic exhaust, a complex mixture, has been studied in its entirety. During recent years, interesting epidemiological studies of the health effects of this complex mixture have been published. Human exposure assessment for traffic exhaust can be categorized according to the environment of exposure (indoors, outdoors, in-traffic) or to the method of exposure assessment (direct or indirect methods). In this presentation the methods are further categorized into (1) traffic activity, (2) air concentration measurements, and (3) dispersion models, in order to better understand the advantages and disadvantages of different approaches. The objective of this presentation is to make a critical review of exposure assessments in the epidemiological studies on health effects of traffic exhaust. (author)

  17. A coupled road dust and surface moisture model to predict non-exhaust road traffic induced particle emissions (NORTRIP). Part 2: Surface moisture and salt impact modelling

    Science.gov (United States)

    Denby, B. R.; Sundvor, I.; Johansson, C.; Pirjola, L.; Ketzel, M.; Norman, M.; Kupiainen, K.; Gustafsson, M.; Blomqvist, G.; Kauhaniemi, M.; Omstedt, G.

    2013-12-01

    Non-exhaust traffic induced emissions are a major source of airborne particulate matter in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. Though the total mass generated by wear sources is a key factor in non-exhaust emissions, these emissions are also strongly controlled by surface moisture conditions. In this paper, Part 2, the road surface moisture sub-model of a coupled road dust and surface moisture model (NORTRIP) is described. We present a description of the road surface moisture part of the model and apply the coupled model to seven sites in Stockholm, Oslo, Helsinki and Copenhagen over 18 separate periods, ranging from 3.5 to 24 months. At two sites surface moisture measurements are available and the moisture sub-model is compared directly to these observations. The model predicts the frequency of wet roads well at both sites, with an average fractional bias of -2.6%. The model is found to correctly predict the hourly surface state, wet or dry, 85% of the time. From the 18 periods modelled using the coupled model an average absolute fractional bias of 15% for PM10 concentrations was found. Similarly the model predicts the 90'th daily mean percentiles of PM10 with an average absolute bias of 19% and an average correlation (R2) of 0.49. When surface moisture is not included in the modelling then this average correlation is reduced to 0.16, demonstrating the importance of the surface moisture conditions. Tests have been carried out to assess the sensitivity of the model to model parameters and input data. The model provides a useful tool for air quality management and for improving our understanding of non-exhaust traffic emissions.

  18. Directive properties of active coated nano-particles

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Ziolkowski, W.

    2012-01-01

    The directivities of the fields radiated by a variety of cylindrical and spherical active coated nano-particles, which are excited by their respective sources of illumination at optical frequencies, are investigated. Particular attention is devoted to the influence of the source location...... and optical gain constant on the directivities. While significant variations in the directivities are realized in the cylindrical cases for different source locations within and slightly outside the nano-particles and values of the optical gain constant, the corresponding spherical cases exhibit negligible...

  19. DNA damage and cytotoxicity in type II lung epithelial (A549) cell cultures after exposure to diesel exhaust and urban street particles.

    Science.gov (United States)

    Danielsen, Pernille Høgh; Loft, Steffen; Møller, Peter

    2008-04-08

    Exposure to air pollution particles has been acknowledged to be associated with excess generation of oxidative damage to DNA in experimental model systems and humans. The use of standard reference material (SRM), such as SRM1650 and SRM2975, is advantageous because experiments can be reproduced independently, but exposure to such samples may not mimic the effects observed after exposure to authentic air pollution particles. This study was designed to compare the DNA oxidizing effects of authentic street particles with SRM1650 and SRM2975. The authentic street particles were collected at a traffic intensive road in Copenhagen, Denmark. All of the particles generated strand breaks and oxidized purines in A549 lung epithelial cells in a dose-dependent manner and there were no overt differences in their potency. The exposures also yielded dose-dependent increase of cytotoxicity (as lactate dehydrogenase release) and reduced colony forming ability with slightly stronger cytotoxicity of SRM1650 than of the other particles. In contrast, only the authentic street particles were able to generate 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in calf thymus DNA, which might be due to the much higher level of transition metals. Authentic street particles and SRMs differ in their ability to oxidize DNA in a cell-free environment, whereas cell culture experiments indicate that the particle preparations elicit a similar alteration of the level of DNA damage and small differences in cytotoxicity. Although it cannot be ruled out that SRMs and authentic street particles might elicit different effects in animal experimental models, this study indicates that on the cellular level, SRM1650 and SRM2975 are suitable surrogate samples for the study of authentic street particles.

  20. Changes in mental health in compliers and non-compliers with physical activity recommendations in patients with stress-related exhaustion.

    Science.gov (United States)

    Lindegård, Agneta; Jonsdottir, Ingibjörg H; Börjesson, Mats; Lindwall, Magnus; Gerber, Markus

    2015-11-04

    There is a lack of research regarding the long-lasting effects of a more physically active lifestyle in patients with mental disorders. In the present study, clinical data were analysed to examine if initially physically inactive patients, clinically diagnosed with stress-related exhaustion, taking part in 12-month multimodal treatment (MMT), differ at the 18-month follow-up regarding mental health, depending on whether they did or did not comply with the physical activity (PA) recommendations resembling those of the American College of Sports Medicine. The study population consisted of 69 patients (65% women) who were referred to a stress clinic due to stress-related exhaustion. All patients received MMT. A major goal was to increase patients' PA levels. The patients received general comprehensive instructions including personal advice regarding the positive effects of PA on mental health and could self-select for an 18-week coached exercise program. Changes in mental health symptoms over an 18-month period were compared between non-compliers (n = 26), mild compliers (n = 22) and strong compliers (n = 21) with the PA recommendations included in the MMT. Non-compliers, mild and strong compliers did not differ regarding burnout, depression and anxiety at baseline. Although substantial improvements occurred in all groups, mild and strong compliers reported significantly lower burnout and depression levels at the 18-month follow-up than the non-complying group (p stress-related exhaustion. Thus, the promotion of a more active lifestyle among patients with stress-related exhaustion should be implemented as a part of MMT, to achieve a more sustainable decrease of symptoms of burnout and depression. This is not a clinical trial.

  1. Comparison of the activities of fine-particle size catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Stohl, F.V.; Diegert, K.V.; Goodnow, D.C.

    1994-12-31

    The objectives of Sandia`s fine-particle size catalyst testing project are to evaluate and compare the activities of the fine-particle size catalysts being developed in DOE/PETCs Advanced Research Coal Liquefaction Program by using standard coal liquefaction test procedures. The standard procedures use Blind Canyon coal, phenanthrene as the reaction solvent, and a factorial experimental design with temperatures from 350{degrees}C to 400{degrees}C, reaction times from 20 to 60 minutes, and catalyst loadings up to 1 wt%. Catalytic activity is measured in terms of tetrahydrofuran conversion, heptane conversion, the amount of 9,10-dihydrophenanthrene in the product, and the gas yield. Several catalysts have been evaluated including a commercially available pyrite, a sulfated iron oxide from the University of Pittsburgh, and several preparations of 6-line ferrihydrites from Pacific Northwest Laboratories. Results have demonstrated that significant differences in activity can be detected among these catalysts.

  2. Inflammatory effects on human lung epithelial cells after exposure to diesel exhaust micron sub particles (PM₁.₀) and pollen allergens.

    Science.gov (United States)

    Mazzarella, G; Esposito, V; Bianco, A; Ferraraccio, F; Prati, M V; Lucariello, A; Manente, L; Mezzogiorno, A; De Luca, A

    2012-02-01

    Asthma is currently defined as a chronic inflammatory disease of the airway. Several evidence indicate that vehicle emissions in cities is correlated with the allergic respiratory diseases. In the present study, we evaluated in the A549 cells the production and release of IL-4, IL-5 and IL-13 after treatment with sub-micron PM(1.0) particles (PM(1.0)), Parietaria officinalis (ALL), and PM(1.0) + ALL together. Our data demonstrated that PM(1.0) + ALL together exhibited the greatest capacity to induce A549 cells to enhance the expression of IL-4 and IL-5 compared with the only PM(1.0) or ALL treatment. Interestingly, IL-13 that is necessary for allergen-induced airway hyper responsiveness, is increased in cells treated with PM(1.0) + ALL together, but is higher expressed when the cells are treated only with the allergen. Our data support the hypothesis that the urban environment damage the acinar lung units and activates cells of the immune system. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Active Brownian particles and run-and-tumble particles separate inside a maze

    Science.gov (United States)

    Khatami, Maryam; Wolff, Katrin; Pohl, Oliver; Ejtehadi, Mohammad Reza; Stark, Holger

    2016-11-01

    A diverse range of natural and artificial self-propelled particles are known and are used nowadays. Among them, active Brownian particles (ABPs) and run-and-tumble particles (RTPs) are two important classes. We numerically study non-interacting ABPs and RTPs strongly confined to different maze geometries in two dimensions. We demonstrate that by means of geometrical confinement alone, ABPs are separable from RTPs. By investigating Matryoshka-like mazes with nested shells, we show that a circular maze has the best filtration efficiency. Results on the mean first-passage time reveal that ABPs escape faster from the center of the maze, while RTPs reach the center from the rim more easily. According to our simulations and a rate theory, which we developed, ABPs in steady state accumulate in the outermost region of the Matryoshka-like mazes, while RTPs occupy all locations within the maze with nearly equal probability. These results suggest a novel technique for separating different types of self-propelled particles by designing appropriate confining geometries without using chemical or biological agents.

  4. Nonequilibrium dynamics of mixtures of active and passive colloidal particles

    Science.gov (United States)

    Wittkowski, Raphael; Stenhammar, Joakim; Cates, Michael E.

    2017-10-01

    We develop a mesoscopic field theory for the collective nonequilibrium dynamics of multicomponent mixtures of interacting active (i.e., motile) and passive (i.e., nonmotile) colloidal particles with isometric shape in two spatial dimensions. By a stability analysis of the field theory, we obtain equations for the spinodal that describes the onset of a motility-induced instability leading to cluster formation in such mixtures. The prediction for the spinodal is found to be in good agreement with particle-resolved computer simulations. Furthermore, we show that in active-passive mixtures the spinodal instability can be of two different types. One type is associated with a stationary bifurcation and occurs also in one-component active systems, whereas the other type is associated with a Hopf bifurcation and can occur only in active-passive mixtures. Remarkably, the Hopf bifurcation leads to moving clusters. This explains recent results from simulations of active-passive particle mixtures, where moving clusters and interfaces that are not seen in the corresponding one-component systems have been observed.

  5. Guiding catalytically active particles with chemically patterned surfaces

    Science.gov (United States)

    Uspal, William; Popescu, Mihail; Dietrich, Siegfried; Tasinkevych, Mykola

    Catalytically active Janus particles in solution create gradients in the chemical composition of the solution along their surfaces, as well as along any nearby container walls. The former leads to self-phoresis, while the latter gives rise to chemi-osmosis, providing an additional contribution to self-motility. Chemi-osmosis strongly depends on the molecular interactions between the diffusing chemical species and the wall. We show analytically, using an approximate ``point-particle'' approach, that by chemically patterning a planar substrate (e.g., by adsorbing two different materials) one can direct the motion of Janus particles: the induced chemi-osmotic flows can cause particles to either ``dock'' at a chemical step between the two materials, or to follow a chemical stripe. These theoretical predictions are confirmed by full numerical calculations. Generically, docking occurs for particles which tend to move away from their catalytic caps, while stripe-following occurs in the opposite case. Our analysis reveals the physical mechanisms governing this behavior.

  6. DNA damage and cytotoxicity in type II lung epithelial (A549) cell cultures after exposure to diesel exhaust and urban street particles

    DEFF Research Database (Denmark)

    Danielsen, Pernille Høgh; Loft, Steffen; Møller, Peter

    2008-01-01

    ABSTRACT: BACKGROUND: Exposure to air pollution particles has been acknowledged to be associated with excess generation of oxidative damage to DNA in experimental model systems and humans. The use of standard reference material (SRM), such as SRM1650 and SRM2975, is advantageous because experiments...... can be reproduced independently, but exposure to such samples may not mimic the effects observed after exposure to authentic air pollution particles. This study was designed to compare the DNA oxidizing effects of authentic street particles with SRM1650 and SRM2975. The authentic street particles were...... and small differences in cytotoxicity. Although it cannot be ruled out that SRMs and authentic street particles might elicit different effects in animal experimental models, this study indicates that on the cellular level, SRM1650 and SRM2975 are suitable surrogate samples for the study of authentic street...

  7. Development of All-Solid-State Sensors for Measurement of Nitric Oxide and Ammonia Concentrations by Optical Absorption in Particle-Laden Combustion Exhaust Streams

    Energy Technology Data Exchange (ETDEWEB)

    Jerald A. Caton; Kalyan Annamalai; Robert P. Lucht

    2006-12-31

    An all-solid-state continuous-wave (cw) laser system for ultraviolet absorption measurements of the nitric oxide (NO) molecule has been developed and demonstrated. For the NO sensor, 250 nW of tunable cw ultraviolet radiation is produced by sum-frequency-mixing of 532-nm radiation from a diode-pumped Nd:YAG laser and tunable 395-nm radiation from an external cavity diode laser (ECDL). The sum-frequency-mixing process occurs in a beta-barium borate crystal. The nitric oxide absorption measurements are performed by tuning the ECDL and scanning the sum-frequency-mixed radiation over strong nitric oxide absorption lines near 226 nm. In Year 1 of the research, the nitric oxide sensor was used for measurements in the exhaust of a coal-fired laboratory combustion facility. The Texas A&M University boiler burner facility is a 30 kW (100,000 Btu/hr) downward-fired furnace with a steel shell encasing ceramic insulation. Measurements of nitric oxide concentration in the exhaust stream were performed after modification of the facility for laser based NOx diagnostics. The diode-laser-based ultraviolet absorption measurements were successful even when the beam was severely attenuated by particulate in the exhaust stream and window fouling. Single-laser-sweep measurements were demonstrated with an effective time resolution of 100 msec, limited at this time by the scan rate of our mechanically tuned ECDL system. In Year 2, the Toptica ECDL in the original system was replaced with a Sacher Lasers ECDL. The mode-hop-free tuning range and tuning rate of the Toptica ECDL were 25 GHz and a few Hz, respectively. The mode-hop-free tuning range and tuning rate of the Sacher Lasers ECDL were 90 GHz and a few hundred Hz, respectively. The Sacher Lasers ECDL thus allows us to scan over the entire NO absorption line and to determine the absorption baseline with increased accuracy and precision. The increased tuning rate is an advantage in that data can be acquired much more rapidly and the

  8. Aircraft exhaust aerosol formation and growth

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.C.; Miake-Lye, R.C.; Anderson, M.R.; Kolb, C.E. [Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics

    1997-12-31

    Aerosol formation and growth in the exhaust plume of the ATTAS aircraft at an altitude of approximately 9 km, burning fuels with 2 ppmm sulfur (`low`) and 266 ppmm (`high`) sulfur has been modeled using an aerosol dynamics model for nucleation, vapor condensation and coagulation, coupled to a 2-dimensional, axisymmetric flow code to treat plume dilution and turbulent mixing. For both the `low` and `high` sulfur fuels, approximately 60% of the available water had condensed within the first 200 m downstream of the exhaust exit. The contrail particle diameters ranged between 0.4 to 1.6 {mu}m. However, the size distributions as a function of radial position for the `low` sulfur plume were broader than the corresponding distributions for the `high` sulfur plume. The model results indicate for a fuel sulfur mass loading of 2 ppmm, sulfuric acid remains a viable activating agent and that the differences in the contrail particle size distributions for sulfur mass loadings between 2 ppmm and 260 ppmm would be difficult to detect. (author) 12 refs.

  9. Focusing of active particles in a converging flow

    Energy Technology Data Exchange (ETDEWEB)

    Potomkin, Mykhailo; Kaiser, Andreas; Berlyand, Leonid; Aranson, Igor

    2017-11-01

    We consider active particles swimming in a convergent fluid flow in a trapezoid nozzle with no-slip walls. We use mathematical modeling to analyze trajectories of these particles inside the nozzle. By extensive Monte Carlo simulations, we show that trajectories are strongly affected by the background fluid flow and geometry of the nozzle leading to wall accumulation and upstream motion (rheotaxis). In particular, we describe the non-trivial focusing of active rods depending on physical and geometrical parameters. It is also established that the convergent component of the background flow leads to stability of both downstream and upstream swimming at the centerline. The stability of downstream swimming enhances focusing, and the stability of upstream swimming enables rheotaxis in the bulk.

  10. BMP-2 and titanium particles synergistically activate osteoclast formation

    Science.gov (United States)

    Sun, S.X.; Guo, H.H.; Zhang, J.; Yu, B.; Sun, K.N.; Jin, Q.H.

    2014-01-01

    A previous study showed that BMP-2 (bone morphogenetic protein-2) and wear debris can separately support osteoclast formation induced by the receptor activator of NF-κB ligand (RANKL). However, the effect of BMP-2 on wear debris-induced osteoclast formation is unclear. In this study, we show that neither titanium particles nor BMP-2 can induce osteoclast formation in RAW 264.7 mouse leukemic monocyte macrophage cells but that BMP-2 synergizes with titanium particles to enhance osteoclast formation in the presence of RANKL, and that at a low concentration, BMP-2 has an optimal effect to stimulate the size and number of multinuclear osteoclasts, expression of osteoclast genes, and resorption area. Our data also clarify that the effects caused by the increase in BMP-2 on phosphorylated SMAD levels such as c-Fos expression increased throughout the early stages of osteoclastogenesis. BMP-2 and titanium particles stimulate the expression of p-JNK, p-P38, p-IkB, and P50 compared with the titanium group. These data suggested that BMP-2 may be a crucial factor in titanium particle-mediated osteoclast formation. PMID:24820069

  11. Continuum Theory of Phase Separation Kinetics for Active Brownian Particles

    Science.gov (United States)

    Stenhammar, Joakim; Tiribocchi, Adriano; Allen, Rosalind J.; Marenduzzo, Davide; Cates, Michael E.

    2013-10-01

    Active Brownian particles (ABPs), when subject to purely repulsive interactions, are known to undergo activity-induced phase separation broadly resembling an equilibrium (attraction-induced) gas-liquid coexistence. Here we present an accurate continuum theory for the dynamics of phase-separating ABPs, derived by direct coarse graining, capturing leading-order density gradient terms alongside an effective bulk free energy. Such gradient terms do not obey detailed balance; yet we find coarsening dynamics closely resembling that of equilibrium phase separation. Our continuum theory is numerically compared to large-scale direct simulations of ABPs and accurately accounts for domain growth kinetics, domain topologies, and coexistence densities.

  12. [Polar neutral organic compounds (POCN) in city aerosols. 2. Measuring of emissions from domestic fuel and vehicle exhaust and from immission particles in Berlin (West)].

    Science.gov (United States)

    Moriske, H J; Freise, R; Schneider, C; Rüden, H

    1987-10-01

    During April and May 1985, some emission samples from private coal firing (domestic fuel) were taken and were fired with two different kind of coal (bituminous and brown coal). Also, measurements were done under different combustion conditions (low and high concentrations of oxygenium during the combustion process). In June and November 1985, some emission samples from heavy diesel-engines were taken in a special tunnel equipment, at different engine conditions. During September 1985, also suspended particulates in a highway traffic tunnel were taken. All these samples were taken using high volume cascade impactors which give a fractionation of the suspended particulates into different particle sizes, according to their retention behaviour in the human respiratory system. The results of these emission samples and samples in the highway tunnel were compared with prior immission measurements of urban suspended particulates in Berlin-West, during January 1984. The etherextractable organic matter (= EEOM) of the total suspended particulate matter (= TPM) was determined using ultrasonic extraction method. The EEOM was separated into an acidic (= AF), a basic (= BF) and a neutral fraction (= NF) by dissolution in acidic and basic agents. Of the neutral fraction (NF), further separation was done into aliphatic compounds (= AIP), polycyclic aromatic hydrocarbons (= PAH) and polar neutral organic compounds (POCN) by using thin layer chromatography. From the PAH and POCN, single compounds were identified by gas chromatographic analysis with dual capillary collumns and internal standard method. All organic fractions were tested to their mutagenic activity in the Salmonella typhimurium mammalian microsome bioassay by Ames. The following results were gained: the neutral fraction (NF) made the highest part of the EEOM (greater than or equal to 60%) whereas the part of the AF amounted to 10-25% and of the basic fraction (BF) to approximatively 5-20%. Making further separation of

  13. Suppression of chlorine activation on aviation-produced volatile particles

    Directory of Open Access Journals (Sweden)

    S. K. Meilinger

    2002-01-01

    Full Text Available We examine the effect of nanometer-sized aircraft-induced aqueous sulfuric acid (H2SO4/H2O particles on atmospheric ozone as a function of temperature. Our calculations are based on a previously derived parameterization for the regional-scale perturbations of the sulfate surface area density due to air traffic in the North Atlantic Flight Corridor (NAFC and a chemical box model. We confirm large scale model results that at temperatures T>210 K additional ozone loss -- mainly caused by hydrolysis of BrONO2 and N2O5 -- scales in proportion with the aviation-produced increase of the background aerosol surface area. However, at lower temperatures (2O and HNO3 uptake enhance scavenging losses of aviation-produced liquid particles and (2 the Kelvin effect efficiently limits chlorine activation on the small aircraft-induced droplets by reducing the solubility of chemically reacting species. These two effects lead to a substantial reduction of heterogeneous chemistry on aircraft-induced volatile aerosols under cold conditions. In contrast we find contrail ice particles to be potentially important for heterogeneous chlorine activation and reductions in ozone levels. These features have not been taken into consideration in previous global studies of the atmospheric impact of aviation. Therefore, to parameterize them in global chemistry and transport models, we propose the following parameterisation: scale the hydrolysis reactions by the aircraft-induced surface area increase, and neglect heterogeneous chlorine reactions on liquid plume particles but not on ice contrails and aircraft induced ice clouds.

  14. Particle emissions from laboratory activities involving carbon nanotubes

    Science.gov (United States)

    Lo, Li-Ming; Tsai, Candace S.-J.; Heitbrink, William A.; Dunn, Kevin H.; Topmiller, Jennifer; Ellenbecker, Michael

    2017-08-01

    This site study was conducted in a chemical laboratory to evaluate nanomaterial emissions from 20-30-nm-diameter bundles of single-walled carbon nanotubes (CNTs) during product development activities. Direct-reading instruments were used to monitor the tasks in real time, and airborne particles were collected using various methods to characterize released nanomaterials using electron microscopy and elemental carbon (EC) analyses. CNT clusters and a few high-aspect-ratio particles were identified as being released from some activities. The EC concentration (0.87 μg/m3) at the source of probe sonication was found to be higher than other activities including weighing, mixing, centrifugation, coating, and cutting. Various sampling methods all indicated different levels of CNTs from the activities; however, the sonication process was found to release the highest amounts of CNTs. It can be cautiously concluded that the task of probe sonication possibly released nanomaterials into the laboratory and posed a risk of surface contamination. Based on these results, the sonication of CNT suspension should be covered or conducted inside a ventilated enclosure with proper filtration or a glovebox to minimize the potential of exposure.

  15. Particle exhaust with vented structures: application to the ergodic divertor of Tore Supra; Pompage des particules dans les tokamaks au moyen d'une structure a events: le divertor ergodique de Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Azeroual, A

    2000-04-04

    In a thermonuclear reactor, one must continuously fuel the discharge and extract the ashes resulting from fusion reactions. To avoid the risk of discharge poisoning, {alpha}-particle concentration is limited to {approx} 10 %. To allow for steady-state conditions requires then to extract {>=}2 % of the helium out flux. In Tore Supra, the ergodic divertor is the main component managing the heat and particle fluxes at the edge. Its principle consists in generating a resonant perturbation able to destroy magnetic surfaces at the plasma periphery. In this region, the field lines are open and connected at both ends to neutralizers which are wetted by the major part of the heat and particle fluxes and are the structures through which a part of the plasma out flux is pumped for maintaining the discharge in steady-state conditions. This work describes the neutral recirculation around the ergodic divertor and is based on a data base of 56 discharges. One discuss the two processes allowing for particle exhaust: the ballistic collection of ions and that of neutrals backscattered by atomic reactions. These two processes are modelled accounting for a realistic description of the divertor geometry. A comparison between simulations and experiments is presented for measurements characterising the three main actors of plasma-wall interaction: the edge plasma, the D{sub {alpha}} light emission and the neutral pressure in the divertor plenum. Last, one question how such a system can be extrapolated to next step machines, for which one must account for technical constraints linked to the presence of the shield protecting the coils from the high neutron flux. (author)

  16. Giant Kovacs-Like Memory Effect for Active Particles

    Science.gov (United States)

    Kürsten, Rüdiger; Sushkov, Vladimir; Ihle, Thomas

    2017-11-01

    Dynamical properties of self-propelled particles obeying a bounded confidence rule are investigated by means of kinetic theory and agent-based simulations. While memory effects are observed in disordered systems, we show that they also occur in active matter systems. In particular, we find that the system exhibits a giant Kovacs-like memory effect that is much larger than predicted by a generic linear theory. Based on a separation of time scales we develop a nonlinear theory to explain this effect. We apply this theory to driven granular gases and propose further applications to spin glasses.

  17. Morphology changes in human lung epithelial cells after exposure to diesel exhaust micron sub particles (PM₁.₀) and pollen allergens.

    Science.gov (United States)

    Esposito, V; Lucariello, A; Savarese, L; Cinelli, M P; Ferraraccio, F; Bianco, A; De Luca, A; Mazzarella, G

    2012-12-01

    In the recent literature there has been an increased interest in the effects of particulate matter on the respiratory tract. The objective of this study was to use an in vitro model of type II lung epithelium (A549) to evaluate the cell ability to take up sub-micron PM(1.0) particles (PM(1.0)), Parietaria officinalis (ALL), and PM(1.0) + ALL together. Morphological analysis performed by Transmission Electron Microscope (TEM) showed that PM and ALL interacted with the cell surface, then penetrating into the cytoplasm. Each single treatment was able to point out a specific change in the morphology. The cells treated appear healthy and not apoptotic. The main effect was the increase of: multilamellar bodies, lysosomal enzymes, microvilli, and presence of vesicle/vacuoles containing particles. These observations demonstrate morphological and functional alterations related to the PM(1.0) and P. officinalis and confirm the induction of the inflammatory response in lung cells exposed to the inhalable particles. Copyright © 2012. Published by Elsevier Ltd.

  18. Active Janus Particles at Interfaces of Liquid Crystals.

    Science.gov (United States)

    Mangal, Rahul; Nayani, Karthik; Kim, Young-Ki; Bukusoglu, Emre; Córdova-Figueroa, Ubaldo M; Abbott, Nicholas L

    2017-10-17

    We report an investigation of the active motion of silica-palladium Janus particles (JPs) adsorbed at interfaces formed between nematic liquid crystals (LCs) and aqueous phases containing hydrogen peroxide (H2O2). In comparison to isotropic oil-aqueous interfaces, we observe the elasticity and anisotropic viscosity of the nematic phase to change qualitatively the active motion of the JPs at the LC interfaces. Although contact line pinning on the surface of the JPs is observed to restrict out-of-plane rotational diffusion of the JPs at LC interfaces, orientational anchoring of nematic LCs on the silica (planar) and palladium (homeotropic) hemispheres biases JP in-plane orientations to generate active motion almost exclusively along the director of the LC at low concentrations of H2O2 (0.5 wt %). In contrast, displacements perpendicular to the director exhibit the characteristics of Brownian diffusion. At higher concentrations of H2O2 (1-3 wt %), we observe an increasing population of JPs propelled parallel and perpendicular to the LC director in a manner consistent with active motion. In addition, under these conditions, we also observe a subpopulation of JPs (approximately 10%) that exhibit active motion exclusively perpendicular to the LC director. These results are discussed in light of independent measurements of the distribution of azimuthal orientations of the JPs at the LC interfaces and calculations of the elastic energies that bias JP orientations. We also contrast our observations at LC interfaces to past studies of self-propulsion of particles within and at the interfaces of isotropic liquids.

  19. Controlled exposure to diesel exhaust and traffic noise - Effects on oxidative stress and activation in mononuclear blood cells

    DEFF Research Database (Denmark)

    Hemmingsen, Jette Gjerke; Møller, Peter; Jantzen, Kim

    2015-01-01

    Particulate air pollution increases risk of cancer and cardiopulmonary disease, partly through oxidative stress. Traffic-related noise increases risk of cardiovascular disease and may cause oxidative stress. In this controlled random sequence study, 18 healthy subjects were exposed for 3h to diesel...... exhaust (DE) at 276μg/m(3) from a passenger car or filtered air, with co-exposure to traffic noise at 48 or 75dB(A). Gene expression markers of inflammation, (interleukin-8 and tumor necrosis factor), oxidative stress (heme oxygenase (decycling-1)) and DNA repair (8-oxoguanine DNA glycosylase (OGG1)) were...... unaltered in peripheral blood mononuclear cells (PBMCs). No significant differences in DNA damage levels, measured by the comet assay, were observed after DE exposure, whereas exposure to high noise levels was associated with significantly increased levels of hOGG1-sensitive sites in PBMCs. Urinary levels...

  20. Mechanisms and implications of air pollution particle associations with chemokines.

    Science.gov (United States)

    Seagrave, Jeanclare

    2008-11-01

    Inflammation induced by inhalation of air pollutant particles has been implicated as a mechanism for the adverse health effects associated with exposure to air pollution. The inflammatory response is associated with upregulation of various pro-inflammatory cytokines and chemokines. We have previously shown that diesel exhaust particles (DEP), a significant constituent of air pollution particulate matter in many urban areas, bind and concentrate IL-8, an important human neutrophil-attracting chemokine, and that the chemokine remains biologically active. In this report, we examine possible mechanisms of this association and the effects on clearance of the chemokine. The binding appears to be the result of ionic interactions between negatively charged particles and positively charged chemokine molecules, possibly combined with intercalation into small pores in the particles. The association is not limited to diesel exhaust particles and IL-8: several other particle types also adsorb the chemokine and several other cytokines are adsorbed onto the diesel particles. However, there are wide ranges in the effectiveness of various particle types and various cytokines. Finally, male Fisher 344 rats were intratracheally instilled with chemokine alone or combined with diesel exhaust or silica particles under isofluorane anesthesia. In contrast to silica particles, which do not bind the chemokine, the presence of diesel exhaust particles, which bind the chemokine, prolonged the retention of the chemokine.

  1. An exhaustion-like phenotype constrains the activity of CD4+ T cells specific for a self and melanoma antigen.

    Directory of Open Access Journals (Sweden)

    Matthew P Rausch

    Full Text Available While the immune system has the capacity to recognize and destroy melanoma, tolerance mechanisms often hinder the development of effective anti-tumor immune responses. Since many melanoma antigens are self proteins expressed in normal melanocytes, self antigen exposure before tumor development can negatively impact the function of T cells specific for these self/tumor antigens. However, the contribution of self tolerance to anti-melanoma T cell dysfunction remains largely unexplored. We have previously described a TCR transgenic (Tg mouse model in which T cells specific for the self/melanoma antigen, tyrosinase-related protein 1 (TRP1, develop in the presence of endogenous TRP1 expression (Ag+ and diminished antigen presentation due to the absence of gamma-interferon-inducible lysosomal thiol reductase (GILT-/-. We show that TRP1-specific T cells from these Ag+GILT-/-Tg mice do not protect from melanoma tumor growth, fail to induce autoimmune vitiligo, and undergo diminished proliferation compared to T cells from Ag-GILT+/+Tg mice. Despite an increased frequency of TRP1-specific Treg cells in Ag+GILT-/-Tg mice compared to Ag-GILT+/+Tg animals, Treg cell depletion only partially rescues the proliferative capacity of T cells from TRP1-expressing mice, suggesting the involvement of additional suppressive mechanisms. An increased percentage of melanoma-specific T cells from Ag+GILT-/-Tg animals express PD-1, an inhibitory receptor associated with the maintenance of T cell exhaustion. Antibody blockade of PD-1 partially improves the ability of TRP1-specific T cells from Ag+GILT-/-Tg mice to produce IL-2. These findings demonstrate that melanoma-specific T cells exposed to a self/melanoma antigen in healthy tissue develop an exhaustion-like phenotype characterized by PD-1-mediated immunosuppression prior to encounter with tumor.

  2. Small intestinal transit of spherical particles in the active rat

    Energy Technology Data Exchange (ETDEWEB)

    Beall, P.T.; Sutton, S.C.; LeRoy-Wayne, S.

    1986-03-05

    Reproducible measurements of small intestine transit for spherical particles of 0.5 ..mu.. to 1 mm diameter, have been accomplished in the conscious rat. A short cannula of polyethylene is surgically implanted into the duodenum and exists through the abdominal wall. After recovery, a bolus of saline containing colored or isotopically labeled particulate material and an internal standard of NaCr/sup 51/O/sub 4/ is introduced with a modified pipette tip that snugly fills the cannula to prevent back flow. The rats eat and drink during the transit period and are maintained on a reversed light cycle so that transit is measured during their physically active period. Glass microspheres of 1mm, 500 ..mu.., and 50 ..mu.. were followed at 30 min, 1 hr, and 2 hr intervals by opening the intestine and photographing 1 cm segments along its length. Polymer beads of 500 ..mu.., 125 ..mu.., and 70 ..mu.. were labeled with /sup 125/I and located by freezing the exteriorized intestine and counting 1 cm segments in a gamma counter. Movement of the fluid bolus as detected by NaCr/sup 51/O/sub 4/ was reproducible with the fluid front moving through 59%, 73%, and 81% of the length at 30 min, 1 hr, and 2 hr. One millimeter to 125 ..mu.. glass and polymer beads moved with the fluid bolus. Evidence for separation of the fluid phase and particles under approx. 100 ..mu.. is accumulating. It is hypothesized that small particles under a critical size may become lodged in the mucus lining of the intestinal wall.

  3. Hyperventilation and exhaustion syndrome.

    Science.gov (United States)

    Ristiniemi, Heli; Perski, Aleksander; Lyskov, Eugene; Emtner, Margareta

    2014-12-01

    Chronic stress is among the most common diagnoses in Sweden, most commonly in the form of exhaustion syndrome (ICD-10 classification - F43.8). The majority of patients with this syndrome also have disturbed breathing (hyperventilation). The aim of this study was to investigate the association between hyperventilation and exhaustion syndrome. Thirty patients with exhaustion syndrome and 14 healthy subjects were evaluated with the Nijmegen Symptom Questionnaire (NQ). The participants completed questionnaires about exhaustion, mental state, sleep disturbance, pain and quality of life. The evaluation was repeated 4 weeks later, after half of the patients and healthy subjects had engaged in a therapy method called 'Grounding', a physical exercise inspired by African dance. The patients reported significantly higher levels of hyperventilation as compared to the healthy subjects. All patients' average score on NQ was 26.57 ± 10.98, while that of the healthy subjects was 15.14 ± 7.89 (t = -3.48, df = 42, p exhaustion (Karolinska Exhaustion Scale KES r = 0.772, p exhaustion scores and scores of depression and anxiety. The conclusion is that hyperventilation is common in exhaustion syndrome patients and that it can be reduced by systematic physical therapy such as Grounding. © 2013 The Authors. Scandinavian Journal of Caring Sciences published by John Wiley & Sons Ltd on behalf of Nordic College of Caring Science.

  4. Local Exhaust Ventilation

    DEFF Research Database (Denmark)

    Madsen, Ulla; Breum, N. O.; Nielsen, Peter V.

    Capture efficiency of a local exhaust system, e.g. a kitchen hood, should include only contaminants being direct captured. In this study basic concepts of local exhaust capture efficiency are given, based on the idea of a control box. A validated numerical model is used for estimation...

  5. Immune Exhaustion and Transplantation.

    Science.gov (United States)

    Sanchez-Fueyo, A; Markmann, J F

    2016-07-01

    Exhaustion of lymphocyte function through chronic exposure to a high load of foreign antigen is well established for chronic viral infection and antitumor immunity and has been found to be associated with a distinct molecular program and characteristic cell surface phenotype. Although exhaustion has most commonly been studied in the context of CD8 viral responses, recent studies indicate that chronic antigen exposure may affect B cells, NK cells and CD4 T cells in a parallel manner. Limited information is available regarding the extent of lymphocyte exhaustion development in the transplant setting and its impact on anti-graft alloreactivity. By analogy to the persistence of a foreign virus, the large mass of alloantigen presented by an allograft in chronic residence could provide an ideal setting for exhausting donor-reactive T cells. The extent of T cell exhaustion occurring with various allografts, the kinetics of its development, whether exhaustion is influenced positively or negatively by different immunosuppressants, and the impact of exhaustion on graft survival and tolerance development remains a fertile area for investigation. Harnessing or encouraging the natural processes of exhaustion may provide a novel means to promote graft survival and transplantation tolerance. © Copyright 2016 The American Society of Transplantation and the American Society of Transplant Surgeons.

  6. Intermediate scattering function of an anisotropic active Brownian particle

    Science.gov (United States)

    Kurzthaler, Christina; Leitmann, Sebastian; Franosch, Thomas

    2016-10-01

    Various challenges are faced when animalcules such as bacteria, protozoa, algae, or sperms move autonomously in aqueous media at low Reynolds number. These active agents are subject to strong stochastic fluctuations, that compete with the directed motion. So far most studies consider the lowest order moments of the displacements only, while more general spatio-temporal information on the stochastic motion is provided in scattering experiments. Here we derive analytically exact expressions for the directly measurable intermediate scattering function for a mesoscopic model of a single, anisotropic active Brownian particle in three dimensions. The mean-square displacement and the non-Gaussian parameter of the stochastic process are obtained as derivatives of the intermediate scattering function. These display different temporal regimes dominated by effective diffusion and directed motion due to the interplay of translational and rotational diffusion which is rationalized within the theory. The most prominent feature of the intermediate scattering function is an oscillatory behavior at intermediate wavenumbers reflecting the persistent swimming motion, whereas at small length scales bare translational and at large length scales an enhanced effective diffusion emerges. We anticipate that our characterization of the motion of active agents will serve as a reference for more realistic models and experimental observations.

  7. How does a flexible chain of active particles swell?

    Science.gov (United States)

    Kaiser, Andreas; Babel, Sonja; ten Hagen, Borge; von Ferber, Christian; Löwen, Hartmut

    2015-03-28

    We study the swelling of a flexible linear chain composed of active particles by analytical theory and computer simulation. Three different situations are considered: a free chain, a chain confined to an external harmonic trap, and a chain dragged at one end. First, we consider an ideal chain with harmonic springs and no excluded volume between the monomers. The Rouse model of polymers is generalized to the case of self-propelled monomers and solved analytically. The swelling, as characterized by the spatial extension of the chain, scales with the monomer number defining a Flory exponent ν which is ν = 1/2, 0, 1 in the three different situations. As a result, we find that activity does not change the Flory exponent but affects the prefactor of the scaling law. This can be quantitatively understood by mapping the system onto an equilibrium chain with a higher effective temperature such that the chain swells under an increase of the self-propulsion strength. We then use computer simulations to study the effect of self-avoidance on active polymer swelling. In the three different situations, the Flory exponent is now ν = 3/4, 1/4, 1 and again unchanged under self-propulsion. However, the chain extension behaves non-monotonic in the self-propulsion strength.

  8. Diesel exhaust exposures in port workers.

    Science.gov (United States)

    Debia, Maximilien; Neesham-Grenon, Eve; Mudaheranwa, Oliver C; Ragettli, Martina S

    2016-07-01

    Exposure to diesel engine exhaust has been linked to increased cancer risk and cardiopulmonary diseases. Diesel exhaust is a complex mixture of chemical substances, including a particulate fraction mainly composed of ultrafine particles, resulting from the incomplete combustion of fuel. Diesel trucks are known to be an important source of diesel-related air pollution, and areas with heavy truck traffic are associated with higher air pollution levels and increased public health problems. Several indicators have been proposed as surrogates for estimating exposures to diesel exhaust but very few studies have focused specifically on monitoring the ultrafine fraction through the measurement of particle number concentrations. The aim of this study is to assess occupational exposures of gate controllers at the port of Montreal, Canada, to diesel engine emissions from container trucks by measuring several surrogates through a multimetric approach which includes the assessment of both mass and number concentrations and the use of direct reading devices. A 10-day measurement campaign was carried out at two terminal checkpoints at the port of Montreal. Respirable elemental and organic carbon, PM1, PM2.5, PMresp (PM4), PM10, PMtot (inhalable fraction), particle number concentrations, particle size distributions, and gas concentrations (NO2, NO, CO) were monitored. Gate controllers were exposed to concentrations of contaminants associated with diesel engine exhaust (elemental carbon GM = 1.6 µg/m(3); GSD = 1.6) well below recommended occupational exposure limits. Average daily particle number concentrations ranged from 16,544-67,314 particles/cm³ (GM = 32,710 particles/cm³; GSD = 1.6). Significant Pearson correlation coefficients were found between daily elemental carbon, PM fractions and particle number concentrations, as well as between total carbon, PM fractions and particle number concentrations. Significant correlation coefficients were found between particle number

  9. Combined exposure of diesel exhaust particles and respirable Soufrière Hills volcanic ash causes a (pro-)inflammatory response in an in vitro multicellular epithelial tissue barrier model.

    Science.gov (United States)

    Tomašek, Ines; Horwell, Claire J; Damby, David E; Barošová, Hana; Geers, Christoph; Petri-Fink, Alke; Rothen-Rutishauser, Barbara; Clift, Martin J D

    2016-12-12

    There are justifiable health concerns regarding the potential adverse effects associated with human exposure to volcanic ash (VA) particles, especially when considering communities living in urban areas already exposed to heightened air pollution. The aim of this study was, therefore, to gain an imperative, first understanding of the biological impacts of respirable VA when exposed concomitantly with diesel particles. A sophisticated in vitro 3D triple cell co-culture model of the human alveolar epithelial tissue barrier was exposed to either a single or repeated dose of dry respirable VA (deposited dose of 0.26 ± 0.09 or 0.89 ± 0.29 μg/cm(2), respectively) from Soufrière Hills volcano, Montserrat for a period of 24 h at the air-liquid interface (ALI). Subsequently, co-cultures were exposed to co-exposures of single or repeated VA and diesel exhaust particles (DEP; NIST SRM 2975; 0.02 mg/mL), a model urban pollutant, at the pseudo-ALI. The biological impact of each individual particle type was also analysed under these precise scenarios. The cytotoxic (LDH release), oxidative stress (depletion of intracellular GSH) and (pro-)inflammatory (TNF-α, IL-8 and IL-1β) responses were assessed after the particulate exposures. The impact of VA exposure upon cell morphology, as well as its interaction with the multicellular model, was visualised via confocal laser scanning microscopy (LSM) and scanning electron microscopy (SEM), respectively. The combination of respirable VA and DEP, in all scenarios, incited an heightened release of TNF-α and IL-8 as well as significant increases in IL-1β, when applied at sub-lethal doses to the co-culture compared to VA exposure alone. Notably, the augmented (pro-)inflammatory responses observed were not mediated by oxidative stress. LSM supported the quantitative assessment of cytotoxicity, with no changes in cell morphology within the barrier model evident. A direct interaction of the VA with all three cell types of

  10. Combined exposure of diesel exhaust particles and respirable Soufrière Hills volcanic ash causes a (pro-)inflammatory response in an in vitro multicellular epithelial tissue barrier model

    Science.gov (United States)

    Tomašek, Ines; Horwell, Claire J.; Damby, David; Barošová, Hana; Geers, Christoph; Petri-Fink, Alke; Rothen-Rutishauser, Barbara; Clift, Martin J. D.

    2016-01-01

    BackgroundThere are justifiable health concerns regarding the potential adverse effects associated with human exposure to volcanic ash (VA) particles, especially when considering communities living in urban areas already exposed to heightened air pollution. The aim of this study was, therefore, to gain an imperative, first understanding of the biological impacts of respirable VA when exposed concomitantly with diesel particles.MethodsA sophisticated in vitro 3D triple cell co-culture model of the human alveolar epithelial tissue barrier was exposed to either a single or repeated dose of dry respirable VA (deposited dose of 0.26 ± 0.09 or 0.89 ± 0.29 μg/cm2, respectively) from Soufrière Hills volcano, Montserrat for a period of 24 h at the air-liquid interface (ALI). Subsequently, co-cultures were exposed to co-exposures of single or repeated VA and diesel exhaust particles (DEP; NIST SRM 2975; 0.02 mg/mL), a model urban pollutant, at the pseudo-ALI. The biological impact of each individual particle type was also analysed under these precise scenarios. The cytotoxic (LDH release), oxidative stress (depletion of intracellular GSH) and (pro-)inflammatory (TNF-α, IL-8 and IL-1β) responses were assessed after the particulate exposures. The impact of VA exposure upon cell morphology, as well as its interaction with the multicellular model, was visualised via confocal laser scanning microscopy (LSM) and scanning electron microscopy (SEM), respectively.ResultsThe combination of respirable VA and DEP, in all scenarios, incited an heightened release of TNF-α and IL-8 as well as significant increases in IL-1β, when applied at sub-lethal doses to the co-culture compared to VA exposure alone. Notably, the augmented (pro-)inflammatory responses observed were not mediated by oxidative stress. LSM supported the quantitative assessment of cytotoxicity, with no changes in cell morphology within the barrier model evident. A direct interaction of the VA with all

  11. Protective Effects of N-Acetyl Cysteine against Diesel Exhaust Particles-Induced Intracellular ROS Generates Pro-Inflammatory Cytokines to Mediate the Vascular Permeability of Capillary-Like Endothelial Tubes.

    Directory of Open Access Journals (Sweden)

    Chia-Yi Tseng

    Full Text Available Exposure to diesel exhaust particles (DEP is associated with pulmonary and cardiovascular diseases. Previous studies using in vitro endothelial tubes as a simplified model of capillaries have found that DEP-induced ROS increase vascular permeability with rearrangement or internalization of adherens junctional VE-cadherin away from the plasma membrane. This allows DEPs to penetrate into the cell and capillary lumen. In addition, pro-inflammatory cytokines are up-regulated and mediate vascular permeability in response to DEP. However, the mechanisms through which these DEP-induced pro-inflammatory cytokines increase vascular permeability remain unknown. Hence, we examined the ability of DEP to induce permeability of human umbilical vein endothelial cell tube cells to investigate these mechanisms. Furthermore, supplementation with NAC reduces ROS production following exposure to DEP. HUVEC tube cells contributed to a pro-inflammatory response to DEP-induced intracellular ROS generation. Endothelial oxidative stress induced the release of TNF-α and IL-6 from tube cells, subsequently stimulating the secretion of VEGF-A independent of HO-1. Our data suggests that DEP-induced intracellular ROS and release of the pro-inflammatory cytokines TNF- α and IL-6, which would contribute to VEGF-A secretion and disrupt cell-cell borders and increase vasculature permeability. Addition of NAC suppresses DEP-induced ROS efficiently and reduces subsequent damages by increasing endogenous glutathione.

  12. 9,10-phenanthrenequinone, a component of diesel exhaust particles, inhibits the reduction of 4-benzoylpyridine and all-trans-retinal and mediates superoxide formation through its redox cycling in pig heart.

    Science.gov (United States)

    Shimada, Hideaki; Oginuma, Michiko; Hara, Akira; Imamura, Yorishige

    2004-08-01

    We have recently purified a tetrameric carbonyl reductase from the cytosolic fraction of pig heart (pig heart carbonyl reductase, PHCR), using 4-benzoylpyridine (4-BP) as the substrate. PHCR has the ability to catalyze efficiently the reduction of 9,10-phenanthrenequinone (PQ) contained in diesel exhaust particles (DEPs). Thus, the present study was attempted to characterize the inhibitory effect of PQ on the reduction of 4-BP and all-trans-retinal in pig heart cytosol. Of the DEP components examined, PQ was the most potent inhibitor for the reduction of 4-BP and all-trans-retinal in pig heart cytosol. PQ also inhibited competitively the 4-BP reduction. These results indicate that PQ inhibits the reduction of 4-BP and all-trans-retinal by acting PHCR present in pig heart cytosol. Furthermore, whether PQ induces the formation of superoxide anion radical was examined in pig heart cytosol. The absorbance of cytochrome c at 550 nm was increased with the time by adding PQ, and the increased absorbance was decreased in the presence of superoxide dismutase. A similar result was observed in the reaction system of recombinant PHCR. On the basis of these results, it is concluded that PQ not only inhibits the reduction of 4-BP and all-trans-retinal catalyzed by PHCR but also mediates superoxide formation through its redox cycling involved in PHCR. We propose the possibility that PQ disturbs the homeostasis of retinoid metabolism and induces oxidative stress in pig heart.

  13. Committee-Based Active Learning for Surrogate-Assisted Particle Swarm Optimization of Expensive Problems.

    Science.gov (United States)

    Wang, Handing; Jin, Yaochu; Doherty, John

    2017-09-01

    Function evaluations (FEs) of many real-world optimization problems are time or resource consuming, posing a serious challenge to the application of evolutionary algorithms (EAs) to solve these problems. To address this challenge, the research on surrogate-assisted EAs has attracted increasing attention from both academia and industry over the past decades. However, most existing surrogate-assisted EAs (SAEAs) either still require thousands of expensive FEs to obtain acceptable solutions, or are only applied to very low-dimensional problems. In this paper, a novel surrogate-assisted particle swarm optimization (PSO) inspired from committee-based active learning (CAL) is proposed. In the proposed algorithm, a global model management strategy inspired from CAL is developed, which searches for the best and most uncertain solutions according to a surrogate ensemble using a PSO algorithm and evaluates these solutions using the expensive objective function. In addition, a local surrogate model is built around the best solution obtained so far. Then, a PSO algorithm searches on the local surrogate to find its optimum and evaluates it. The evolutionary search using the global model management strategy switches to the local search once no further improvement can be observed, and vice versa. This iterative search process continues until the computational budget is exhausted. Experimental results comparing the proposed algorithm with a few state-of-the-art SAEAs on both benchmark problems up to 30 decision variables as well as an airfoil design problem demonstrate that the proposed algorithm is able to achieve better or competitive solutions with a limited budget of hundreds of exact FEs.

  14. Metabolic activation of diesel exhaust carcinogens in primary and immortalized human TP53 knock-in (Hupki) mouse embryo fibroblasts.

    Science.gov (United States)

    Kucab, Jill E; Phillips, David H; Arlt, Volker M

    2012-04-01

    Approximately 50% of human tumors have a mutation in TP53. The pattern and spectra of TP53 mutations often differ between cancer types, perhaps due to different etiological factors. The Hupki (human TP53 knock-in) mouse embryo fibroblast (HUF) immortalization assay is useful for studying mutagenesis in the human TP53 gene by environmental carcinogens. Prior to initiating an immortalization assay, carcinogen treatment conditions must be optimized, which can require a large number of cells. As primary HUF cultures senesce within 2 weeks, restricting their use, we investigated whether immortalized HUFs retaining wild-type TP53 can be surrogates for primary HUFs in initial treatment optimization. DNA damage by eight compounds found in diesel exhaust, benzo[a]pyrene, 3-nitrobenzanthrone, 1-nitropyrene, 1,3-dinitropyrene, 1,6-dinitropyrene, 1,8-dinitropyrene, 6-nitrochrysene, and 3-nitrofluorene, was assessed by (32) P-postlabeling and the alkaline comet assay in primary HUFs and in an immortal HUF cell line J201. For most compounds, higher levels of DNA adducts accumulated in J201 cells than in primary HUFs. This difference was not reflected in the comet assay or by cell viability changes. Experiments in three additional immortal HUF cell lines (AAI49, U56, and E2-143) confirmed strong differences in DNA adduct levels compared with primary HUFs. However, these did not correlate with the protein expression of Nqo1 or Nat1/2, or with gene expression of Cyp1a1 or Cyp1b1. Our results show that using immortal HUFs as surrogates for primary HUFs in genotoxicity screening has limitations and that DNA adduct formation is the best measure of genotoxicity of the nitro-polycyclic aromatic hydrocarbons tested in HUFs. Copyright © 2011 Wiley Periodicals, Inc.

  15. Ragweed Subpollen Particles of Respirable Size Activate Human Dendritic Cells

    Science.gov (United States)

    Pazmandi, Kitti; Kumar, Brahma V.; Szabo, Krisztina; Boldogh, Istvan; Szoor, Arpad; Vereb, Gyorgy; Veres, Agota; Lanyi, Arpad; Rajnavolgyi, Eva; Bacsi, Attila

    2012-01-01

    Ragweed (Ambrosia artemisiifolia) pollen grains, which are generally considered too large to reach the lower respiratory tract, release subpollen particles (SPPs) of respirable size upon hydration. These SPPs contain allergenic proteins and functional NAD(P)H oxidases. In this study, we examined whether exposure to SPPs initiates the activation of human monocyte-derived dendritic cells (moDCs). We found that treatment with freshly isolated ragweed SPPs increased the intracellular levels of reactive oxygen species (ROS) in moDCs. Phagocytosis of SPPs by moDCs, as demonstrated by confocal laser-scanning microscopy, led to an up-regulation of the cell surface expression of CD40, CD80, CD86, and HLA-DQ and an increase in the production of IL-6, TNF-α, IL-8, and IL-10. Furthermore, SPP-treated moDCs had an increased capacity to stimulate the proliferation of naïve T cells. Co-culture of SPP-treated moDCs with allogeneic CD3+ pan-T cells resulted in increased secretion of IFN-γ and IL-17 by T cells of both allergic and non-allergic subjects, but induced the production of IL-4 exclusively from the T cells of allergic individuals. Addition of exogenous NADPH further increased, while heat-inactivation or pre-treatment with diphenyleneiodonium (DPI), an inhibitor of NADPH oxidases, strongly diminished, the ability of SPPs to induce phenotypic and functional changes in moDCs, indicating that these processes were mediated, at least partly, by the intrinsic NAD(P)H oxidase activity of SPPs. Collectively, our data suggest that inhaled ragweed SPPs are fully capable of activating dendritic cells (DCs) in the airways and SPPs' NAD(P)H oxidase activity is involved in initiation of adaptive immune responses against innocuous pollen proteins. PMID:23251688

  16. Ragweed subpollen particles of respirable size activate human dendritic cells.

    Directory of Open Access Journals (Sweden)

    Kitti Pazmandi

    Full Text Available Ragweed (Ambrosia artemisiifolia pollen grains, which are generally considered too large to reach the lower respiratory tract, release subpollen particles (SPPs of respirable size upon hydration. These SPPs contain allergenic proteins and functional NAD(PH oxidases. In this study, we examined whether exposure to SPPs initiates the activation of human monocyte-derived dendritic cells (moDCs. We found that treatment with freshly isolated ragweed SPPs increased the intracellular levels of reactive oxygen species (ROS in moDCs. Phagocytosis of SPPs by moDCs, as demonstrated by confocal laser-scanning microscopy, led to an up-regulation of the cell surface expression of CD40, CD80, CD86, and HLA-DQ and an increase in the production of IL-6, TNF-α, IL-8, and IL-10. Furthermore, SPP-treated moDCs had an increased capacity to stimulate the proliferation of naïve T cells. Co-culture of SPP-treated moDCs with allogeneic CD3(+ pan-T cells resulted in increased secretion of IFN-γ and IL-17 by T cells of both allergic and non-allergic subjects, but induced the production of IL-4 exclusively from the T cells of allergic individuals. Addition of exogenous NADPH further increased, while heat-inactivation or pre-treatment with diphenyleneiodonium (DPI, an inhibitor of NADPH oxidases, strongly diminished, the ability of SPPs to induce phenotypic and functional changes in moDCs, indicating that these processes were mediated, at least partly, by the intrinsic NAD(PH oxidase activity of SPPs. Collectively, our data suggest that inhaled ragweed SPPs are fully capable of activating dendritic cells (DCs in the airways and SPPs' NAD(PH oxidase activity is involved in initiation of adaptive immune responses against innocuous pollen proteins.

  17. Task failure during exercise to exhaustion in normoxia and hypoxia is due to reduced muscle activation caused by central mechanisms while muscle metaboreflex does not limit performance

    Directory of Open Access Journals (Sweden)

    Rafael eTorres-Peralta

    2016-01-01

    Full Text Available To determine whether task failure during incremental exercise to exhaustion (IE is principally due to reduced neural drive and increased metaboreflex activation eleven men (22±2 years performed a 10s control isokinetic sprint (IS; 80 rpm after a short warm-up. This was immediately followed by an IE in normoxia (Nx, PIO2:143 mmHg and hypoxia (Hyp, PIO2:73 mmHg in random order, separated by a 120 min resting period. At exhaustion, the circulation of both legs was occluded instantaneously (300 mmHg during 10 or 60s to impede recovery and increase metaboreflex activation. This was immediately followed by an IS with open circulation. Electromyographic recordings were obtained from the vastus medialis and lateralis. Muscle biopsies and blood gases were obtained in separate experiments. During the last 10s of the IE, pulmonary ventilation, VO2, power output and muscle activation were lower in hypoxia than in normoxia, while pedaling rate was similar. Compared to the control sprint, performance (IS-Wpeak was reduced to a greater extent after the IE-Nx (11% lower P<0.05 than IE-Hyp. The root mean square (EMGRMS was reduced by 38 and 27% during IS performed after IE-Nx and IE-Hyp, respectively (Nx vs. Hyp: P<0.05. Post-ischemia IS-EMGRMS values were higher than during the last 10s of IE. Sprint exercise mean (IS-MPF and median (IS-MdPF power frequencies, and burst duration, were more reduced after IE-Nx than IE-Hyp (P<0.05. Despite increased muscle lactate accumulation, acidification, and metaboreflex activation from 10 to 60s of ischemia, IS-Wmean (+23% and burst duration (+10% increased, while IS-EMGRMS decreased (-24%, P<0.05, with IS-MPF and IS-MdPF remaining unchanged. In conclusion, close to task failure, muscle activation is lower in hypoxia than in normoxia. Task failure is predominantly caused by central mechanisms, which recover to great extent within one minute even when the legs remain ischemic. There is dissociation between the recovery of

  18. Tracking Deforming Objects using Particle Filtering for Geometric Active Contours

    National Research Council Canada - National Science Library

    Rathi, Yogesh; Vaswani, Namrata; Tannenbaum, Allen; Yezzi, Anthony

    2007-01-01

    .... Tracking algorithms using Kalman filters or particle filters have been proposed for finite dimensional representations of shape, but these are dependent on the chosen parametrization and cannot...

  19. Multiscale Mathematics for Nano-Particle-Endowed Active Membranes and Films

    Science.gov (United States)

    2016-08-03

    AFRL-AFOSR-VA-TR-2016-0284 Multiscale Mathematics for Nano - Particle -Endowed Active Membranes and Films Qi Wang SOUTH CAROLINA RESEARCH FOUNDATION...01-05-2012 to 30-04-2016 4. TITLE AND SUBTITLE Multiscale Mathematics for Nano - Particle -Endowed Active Membranes and Films 5a. CONTRACT NUMBER 5b...Carolina Grant/Contract Title The full title of the funded effort. Multiscale Mathematics for Nano - Particle -Endowed Active Membranes and Films Grant

  20. NK Cell Exhaustion

    Science.gov (United States)

    Bi, Jiacheng; Tian, Zhigang

    2017-01-01

    Natural killer cells are important effector lymphocytes of the innate immune system, playing critical roles in antitumor and anti-infection host defense. Tumor progression or chronic infections, however, usually leads to exhaustion of NK cells, thus limiting the antitumor/infection potential of NK cells. In many tumors or chronic infections, multiple mechanisms might contribute to the exhaustion of NK cells, such as dysregulated NK cell receptors signaling, as well as suppressive effects by regulatory cells or soluble factors within the microenvironment. Better understanding of the characteristics, as well as the underlying mechanisms of NK cell exhaustion, not only should increase our understanding of the basic biology of NK cells but also could reveal novel NK cell-based antitumor/infection targets. Here, we provide an overview of our current knowledge on NK cell exhaustion in tumors, and in chronic infections. PMID:28702032

  1. Unemployment Benefit Exhaustion

    DEFF Research Database (Denmark)

    Filges, Trine; Pico Geerdsen, Lars; Knudsen, Anne-Sofie Due

    2015-01-01

    This systematic review studied the impact of exhaustion of unemployment benefits on the exit rate out of unemployment and into employment prior to benefit exhaustion or shortly thereafter. Method: We followed Campbell Collaboration guidelines to prepare this review, and ultimately located 12...... studies for final analysis and interpretation. Twelve studies could be included in the data synthesis. Results: We found clear evidence that the prospect of exhaustion of benefits results in a significantly increased incentive for finding work. Discussion: The theoretical suggestion that the prospect...... of exhaustion of benefits results in an increased incentive for finding work has been confirmed empirically by measures from seven different European countries, the United States, and Canada. The results are robust in the sense that sensitivity analyses evidenced no appreciable changes in the results. We found...

  2. Immune Exhaustion and Transplantation

    National Research Council Canada - National Science Library

    Sanchez‐Fueyo, A; Markmann, J. F

    2016-01-01

    Exhaustion of lymphocyte function through chronic exposure to a high load of foreign antigen is well established for chronic viral infection and antitumor immunity and has been found to be associated...

  3. Modelling Collective Opinion Formation by Means of Active Brownian Particles

    CERN Document Server

    Schweitzer, F; Schweitzer, Frank; Holyst, Janusz

    1999-01-01

    The concept of active Brownian particles is used to model a collective opinion formation process. It is assumed that individuals in community create a two-component communication field that influences the change of opinions of other persons and/or can induce their migration. The communication field is described by a reaction-diffusion equation, meaning that it has a certain lifetime, which models memory effects, further it can spread out in the community. Within our stochastic approach, the opinion change of the individuals is described by a master equation, while the migration is described by a set of Langevin equations, coupled by the communication field. In the mean-field limit which holds for fast communication, we derive a critical population size, above which the community separates into a majority and a minority with opposite opinions. The existence of external support (e.g. from mass media) can change the ratio between minority and majority, until above a critical external support the supported subpop...

  4. Relation between cooperative molecular motors and active Brownian particles.

    Science.gov (United States)

    Touya, Clément; Schwalger, Tilo; Lindner, Benjamin

    2011-05-01

    Active Brownian particles (ABPs), obeying a nonlinear Langevin equation with speed-dependent drift and noise amplitude, are well-known models used to describe self-propelled motion in biology. In this paper we study a model describing the stochastic dynamics of a group of coupled molecular motors (CMMs). Using two independent numerical methods, one based on the stationary velocity distribution of the motors and the other one on the local increments (also known as the Kramers-Moyal coefficients) of the velocity, we establish a connection between the CMM and the ABP models. The parameters extracted for the ABP via the two methods show good agreement for both symmetric and asymmetric cases and are independent of N, the number of motors, provided that N is not too small. This indicates that one can indeed describe the CMM problem with a simpler ABP model. However, the power spectrum of velocity fluctuations in the CMM model reveals a peak at a finite frequency, a peak which is absent in the velocity spectrum of the ABP model. This implies richer dynamic features of the CMM model which cannot be captured by an ABP model.

  5. Activating Molecules, Ions, and Solid Particles with Acoustic Cavitation

    Science.gov (United States)

    Pflieger, Rachel; Chave, Tony; Virot, Matthieu; Nikitenko, Sergey I.

    2014-01-01

    The chemical and physical effects of ultrasound arise not from a direct interaction of molecules with sound waves, but rather from the acoustic cavitation: the nucleation, growth, and implosive collapse of microbubbles in liquids submitted to power ultrasound. The violent implosion of bubbles leads to the formation of chemically reactive species and to the emission of light, named sonoluminescence. In this manuscript, we describe the techniques allowing study of extreme intrabubble conditions and chemical reactivity of acoustic cavitation in solutions. The analysis of sonoluminescence spectra of water sparged with noble gases provides evidence for nonequilibrium plasma formation. The photons and the "hot" particles generated by cavitation bubbles enable to excite the non-volatile species in solutions increasing their chemical reactivity. For example the mechanism of ultrabright sonoluminescence of uranyl ions in acidic solutions varies with uranium concentration: sonophotoluminescence dominates in diluted solutions, and collisional excitation contributes at higher uranium concentration. Secondary sonochemical products may arise from chemically active species that are formed inside the bubble, but then diffuse into the liquid phase and react with solution precursors to form a variety of products. For instance, the sonochemical reduction of Pt(IV) in pure water provides an innovative synthetic route for monodispersed nanoparticles of metallic platinum without any templates or capping agents. Many studies reveal the advantages of ultrasound to activate the divided solids. In general, the mechanical effects of ultrasound strongly contribute in heterogeneous systems in addition to chemical effects. In particular, the sonolysis of PuO2 powder in pure water yields stable colloids of plutonium due to both effects. PMID:24747272

  6. Proinflammatory effects of diesel exhaust particles from moderate blend concentrations of 1st and 2nd generation biodiesel in BEAS-2B bronchial epithelial cells-The FuelHealth project.

    Science.gov (United States)

    Skuland, Tonje S; Refsnes, Magne; Magnusson, Pål; Oczkowski, Michał; Gromadzka-Ostrowska, Joanna; Kruszewski, Marcin; Mruk, Remigiusz; Myhre, Oddvar; Lankoff, Anna; Øvrevik, Johan

    2017-06-01

    Biodiesel fuel fuels are introduced at an increasing extent as a more carbon-neutral alternative to reduce CO 2 -emissions, compared to conventional diesel fuel. In the present study we have investigated the impact of increasing the use of 1st generation fatty acid methyl ester (FAME) biodiesel from current 7% blend (B7) to 20% blend (B20), or by increasing the biodiesel content by adding 2nd generation hydrotreated vegetable oil (HVO) based biodiesel (SHB; Synthetic Hydrocarbon Biofuel) on toxicity of diesel exhaust particles (DEP) in an in vitro system. Human bronchial epithelial BEAS-2B cells were exposed for 4 and 20h to DEP from B7, B20 and SHB at different concentrations, and examined for effects on gene expression of interleukin 6 (IL-6), CXCL8 (IL-8), CYP1A1 and heme oxygenase-1 (HO-1). The results show that both B20 and SHB were more potent inducers of IL-6 expression compared to B7. Only B20 induced statistically significant increases in CXCL8 expression. By comparison the rank order of potency to induce CYP1A1 was SHB>B7>B20. No statistically significant difference were observed form HO-1 expression, suggesting that the differences in cytokine responses were not due to oxidative stress. The results show that even moderate increases in biodiesel blends, from 7% to 20%, may increase the proinflammatory potential of emitted DEP in BEAS-2B cells. This effect was observed for both addition of 1st generation FAME and 2nd generation HVO biodiesel. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. T-cell exhaustion in the tumor microenvironment

    Science.gov (United States)

    Jiang, Y; Li, Y; Zhu, B

    2015-01-01

    T-cell exhaustion was originally identified during chronic infection in mice, and was subsequently observed in humans with cancer. The exhausted T cells in the tumor microenvironment show overexpressed inhibitory receptors, decreased effector cytokine production and cytolytic activity, leading to the failure of cancer elimination. Restoring exhausted T cells represents an inspiring strategy for cancer treatment, which has yielded promising results and become a significant breakthrough in the cancer immunotherapy. In this review, we overview the updated understanding on the exhausted T cells in cancer and their potential regulatory mechanisms and discuss current therapeutic interventions targeting exhausted T cells in clinical trials. PMID:26086965

  8. Sampling and measurement methods for diesel exhaust aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Ristimaeki, J.

    2006-07-01

    Awareness of adverse health effects of urban aerosols has increased general interest in aerosol sources. As diesel engines are one significant urban anthropogenic particle source, diesel aerosols have been under intense research during the last decades. This thesis discusses the measurement issues related to the diesel exhaust particles, focusing on the effective density measurement with Elpi-Sumps and Tda-Elpi methods and presents some additional performance issues not discussed in the papers. As the emergence of volatile nanoparticles in the diesel exhaust is sensitive to prevailing circumstances there is a need to properly control the dilution parameters in laboratory measurements in order to obtain repeatable and reproducible results. In addition to the dilution parameters, the effect of ambient temperature on the light duty vehicle exhaust particulate emission was studied. It was found that turbo charged diesel engines were relatively insensitive to changes in ambient temperature whereas particle emissions from naturally aspirated gasoline vehicles were significantly increased at low temperatures. The measurement of effective density and mass of aerosol particles with Dma and impactor was studied and applied to characterisation of diesel exhaust particles. The Tda-Elpi method was used for determination of the volatile mass of diesel exhaust particles as a function of particle size. Based on the measurement results, condensation was suggested to be the main phenomena driving volatile mass transfer to the exhaust particles. Identification of the process and the separation of volatile and solid mass may become important as some health effect studies suggest the volatile fraction to be a key component causing the biological effects of diesel exhaust particles. (orig.)

  9. T-cell exhaustion in the tumor microenvironment

    National Research Council Canada - National Science Library

    Jiang, Y; Li, Y; Zhu, B

    2015-01-01

    .... The exhausted T cells in the tumor microenvironment show overexpressed inhibitory receptors, decreased effector cytokine production and cytolytic activity, leading to the failure of cancer elimination...

  10. Fabrication, Characterization, and Biological Activity of Avermectin Nano-delivery Systems with Different Particle Sizes

    Science.gov (United States)

    Wang, Anqi; Wang, Yan; Sun, Changjiao; Wang, Chunxin; Cui, Bo; Zhao, Xiang; Zeng, Zhanghua; Yao, Junwei; Yang, Dongsheng; Liu, Guoqiang; Cui, Haixin

    2018-01-01

    Nano-delivery systems for the active ingredients of pesticides can improve the utilization rates of pesticides and prolong their control effects. This is due to the nanocarrier envelope and controlled release function. However, particles containing active ingredients in controlled release pesticide formulations are generally large and have wide size distributions. There have been limited studies about the effect of particle size on the controlled release properties and biological activities of pesticide delivery systems. In the current study, avermectin (Av) nano-delivery systems were constructed with different particle sizes and their performances were evaluated. The Av release rate in the nano-delivery system could be effectively controlled by changing the particle size. The biological activity increased with decreasing particle size. These results suggest that Av nano-delivery systems can significantly improve the controllable release, photostability, and biological activity, which will improve efficiency and reduce pesticide residues.

  11. Executive control, ERP and pro-inflammatory activity in emotionally exhausted middle-aged employees. Comparison between subclinical burnout and mild to moderate depression.

    Science.gov (United States)

    Gajewski, Patrick D; Boden, Sylvia; Freude, Gabriele; Potter, Guy G; Claus, Maren; Bröde, Peter; Watzl, Carsten; Getzmann, Stephan; Falkenstein, Michael

    2017-12-01

    Burnout is a syndrome occurring mainly in individuals with long-term stressful work. The main complaints are emotional exhaustion and reduced performance. Burnout also largely overlaps with depression. Both are characterized by increased incidence of infections due to dysregulation of the immune system, overexpression of pro-inflammatory cytokines and cognitive deficits, particularly related to executive functions. To distinguish between burnout and depression already at the pre-clinical stage, the present double-blinded study compared immunological and cognitive parameters in seventy-six employees from emotionally demanding occupations who were post-hoc subdivided into two groups scoring low (EE-) and high (EE+) in emotional exhaustion and low (DE-) and high (DE+) in depression. Immunological parameters were measured from blood samples. Executive functions were studied by analyzing event-related brain potentials (ERPs) and performance during a task switching paradigm. Psychosocial job parameters were measured with standardized questionnaires. Burnout and mild to moderate depression largely overlapped. However, several subjects showed burnout without depressive symptoms. Higher levels of the pro-inflammatory cytokines IL-6 and IL-12 were correlated with burnout severity and depressive symptoms in male individuals. In the switch task a trend for lower performance in the EE+ vs. EE- group and no difference between DE+ and DE- groups were found. In the ERPs, however, differences were observed which distinguished between subclinical burnout and depression: the terminal contingent negative variation (CNV), indicating preparatory activity and the P3b, related to allocation of cognitive resources were generally reduced in EE+ vs. EE-, whereas no differences were found in the DE+ vs. DE- groups. The frontal P3a was selectively reduced in switch trials in the EE+ vs. EE- group and showed only a trend in DE+ vs. DE-, indicating impairment of executive control in subclinical

  12. Photocatalytic activity of nanostructured copper (ii) oxide Particles ...

    African Journals Online (AJOL)

    Copper (II) Oxide nanostructured particles have been successfully synthesized by a simple wet chemistry method. The materials obtained were characterized and applied in photodegradation of methylene blue. The XRD pattern obtained reveals crystallinity with major peaks at 2q values 35.53°, 38.71° and 48.75° exhibiting ...

  13. High energy photon and particle luminosity from active nuclei

    Science.gov (United States)

    Eilek, J. A.; Caroff, L. J.; Noerdlinger, P. D.; Dove, M. E.

    1986-01-01

    This paper describes a numerical calculation which follows the evolution of an initial photon and particle spectrum in an expanding, relativistic wind or jet, describes in particular the quasi-equilibrium distribution found for initial optical depths above 100 or so, and points out that this calculation may be relevant for the situation in luminous, compact nuclear sources.

  14. The influence of human physical activity and contaminated clothing type on particle resuspension.

    Science.gov (United States)

    McDonagh, A; Byrne, M A

    2014-01-01

    A study was conducted to experimentally quantify the influence of three variables on the level of resuspension of hazardous aerosol particles from clothing. Variables investigated include physical activity level (two levels, low and high), surface type (four different clothing material types), and time i.e. the rate at which particles resuspend. A mixture of three monodisperse tracer-labelled powders, with median diameters of 3, 5, and 10 microns, was used to "contaminate" the samples, and the resuspended particles were analysed in real-time using an Aerodynamic Particle Sizer (APS), and also by Neutron Activation Analysis (NAA). The overall finding was that physical activity resulted in up to 67% of the contamination deposited on clothing being resuspended back into the air. A detailed examination of the influence of physical activity level on resuspension, from NAA, revealed that the average resuspended fraction (RF) of particles at low physical activity was 28 ± 8%, and at high physical activity was 30 ± 7%, while the APS data revealed a tenfold increase in the cumulative mass of airborne particles during high physical activity in comparison to that during low physical activity. The results also suggest that it is not the contaminated clothing's fibre type which influences particle resuspension, but the material's weave pattern (and hence the material's surface texture). Investigation of the time variation in resuspended particle concentrations indicated that the data were separable into two distinct regimes: the first (occurring within the first 1.5 min) having a high, positive rate of change of airborne particle concentration relative to the second regime. The second regime revealed a slower rate of change of particle concentration and remained relatively unchanged for the remainder of each resuspension event. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Aerodynamic Control of Exhaust

    DEFF Research Database (Denmark)

    Hyldgård, Carl-Erik

    In the autumn of 1985 the Unive!Sity of Aalborg was approached by the manufacturer C. P. Aaberg, who had obtained aerodynilmic control of the exhaust by means of injection. The remaining investigations comprising optimizations of the system with regard to effect, consumption, requirements...

  16. Exhaust bypass flow control for exhaust heat recovery

    Science.gov (United States)

    Reynolds, Michael G.

    2015-09-22

    An exhaust system for an engine comprises an exhaust heat recovery apparatus configured to receive exhaust gas from the engine and comprises a first flow passage in fluid communication with the exhaust gas and a second flow passage in fluid communication with the exhaust gas. A heat exchanger/energy recovery unit is disposed in the second flow passage and has a working fluid circulating therethrough for exchange of heat from the exhaust gas to the working fluid. A control valve is disposed downstream of the first and the second flow passages in a low temperature region of the exhaust heat recovery apparatus to direct exhaust gas through the first flow passage or the second flow passage.

  17. T cell exhaustion and Interleukin 2 downregulation.

    Science.gov (United States)

    Balkhi, Mumtaz Y; Ma, Qiangzhong; Ahmad, Shazia; Junghans, Richard P

    2015-02-01

    T cells reactive to tumor antigens and viral antigens lose their reactivity when exposed to the antigen-rich environment of a larger tumor bed or viral load. Such non-responsive T cells are termed exhausted. T cell exhaustion affects both CD8+ and CD4+ T cells. T cell exhaustion is attributed to the functional impairment of T cells to produce cytokines, of which the most important may be Interleukin 2 (IL2). IL2 performs functions critical for the elimination of cancer cells and virus infected cells. In one such function, IL2 promotes CD8+ T cell and natural killer (NK) cell cytolytic activities. Other functions include regulating naïve T cell differentiation into Th1 and Th2 subsets upon exposure to antigens. Thus, the signaling pathways contributing to T cell exhaustion could be linked to the signaling pathways contributing to IL2 loss. This review will discuss the process of T cell exhaustion and the signaling pathways that could be contributing to T cell exhaustion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Facile Hydrothermal Preparation and Photocatalytic Activity of Bismuth Tungstate Polycrystalline Flake-ball Particles

    OpenAIRE

    Amano, Fumiaki; Nogami, Kohei; Abe, Ryu; Ohtani, Bunsho

    2007-01-01

    Micrometer-sized spherical particles of bismuth tungstate (Bi2WO6) with hierarchical architecture were prepared by facile hydrothermal reaction without using any surfactants and polymers as structure-directing agents. The particles were assemblies of polycrystalline flakes composed of rectangular platelets. The hierarchical polycrystalline particles of “flake-ball” shape exhibited relatively high photocatalytic activity for oxidative decomposition of acetic acid in aqueous suspensions.

  19. Protective effects of pulmonary epithelial lining fluid on oxidative stress and DNA single-strand breaks caused by ultrafine carbon black, ferrous sulphate and organic extract of diesel exhaust particles

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Hsiao-Chi [School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan (China); Cheng, Yi-Ling; Lei, Yu-Chen [Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan (China); Chang, Hui-Hsien [Institute of Environmental Health, College of Public Health, National Taiwan University, Taipei, Taiwan (China); Cheng, Tsun-Jen, E-mail: tcheng@ntu.edu.tw [Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan (China); Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan (China)

    2013-02-01

    Pulmonary epithelial lining fluid (ELF) is the first substance to make contact with inhaled particulate matter (PM) and interacts chemically with PM components. The objective of this study was to determine the role of ELF in oxidative stress, DNA damage and the production of proinflammatory cytokines following physicochemical exposure to PM. Ultrafine carbon black (ufCB, 15 nm; a model carbonaceous core), ferrous sulphate (FeSO{sub 4}; a model transition metal) and a diesel exhaust particle (DEP) extract (a model organic compound) were used to examine the acellular oxidative potential of synthetic ELF and non-ELF systems. We compared the effects of exposure to ufCB, FeSO{sub 4} and DEP extract on human alveolar epithelial Type II (A549) cells to determine the levels of oxidative stress, DNA single-strand breaks and interleukin-8 (IL-8) production in ELF and non-ELF systems. The effects of ufCB and FeSO{sub 4} on the acellular oxidative potential, cellular oxidative stress and DNA single-strand breakage were mitigated significantly by the addition of ELF, whereas there was no decrease following treatment with the DEP extract. There was no significant effect on IL-8 production following exposure to samples that were suspended in ELF/non-ELF systems. The results of the present study indicate that ELF plays an important role in the initial defence against PM in the pulmonary environment. Experimental components, such as ufCB and FeSO{sub 4}, induced the production of oxidative stress and led to DNA single-strand breaks, which were moderately prevented by the addition of ELF. These findings suggest that ELF plays a protective role against PM-driven oxidative stress and DNA damage. -- Highlights: ► To determine the role of ELF in ROS, DNA damage and IL-8 after exposure to PM. ► ufCB, FeSO{sub 4} and DEP extract were used to examine the protective effects of ELF. ► PM-driven oxidative stress and DNA single-strand breakage were mitigated by ELF. ► The findings

  20. Active quadrupole stabilization for future linear particle colliders

    CERN Document Server

    Collette, Christophe; Kuzmin, Andrey; Janssens, Stef; Sylte, Magnus; Guinchard, Michael; Hauviller, Claude

    2010-01-01

    The future Compact LInear particle Collider (CLIC) under study at CERN will require to stabilize heavy electromagnets, and also to provide them some positioning capabilities. Firstly, this paper presents the concept adopted to address both requirements. Secondly, the control strategy adopted for the stabilization is studied numerically, showing that the quadrupole can be stabilized in both lateral and vertical direction. Finally, the strategy is validated experimentally on a single degree of freedom scaled test bench.

  1. Sources of optically active aerosol particles over the Amazon forest

    Science.gov (United States)

    Guyon, Pascal; Graham, Bim; Roberts, Gregory C.; Mayol-Bracero, Olga L.; Maenhaut, Willy; Artaxo, Paulo; Andreae, Meinrat O.

    Size-fractionated ambient aerosol samples were collected at a pasture site and a primary rainforest site in the Brazilian Amazon Basin during two field campaigns (April-May and September-October 1999), as part of the European contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA-EUSTACH). The samples were analyzed for up to 19 trace elements by particle-induced X-ray emission analysis (PIXE), for equivalent black carbon (BC e) by a light reflectance technique and for mass concentration by gravimetric analysis. Additionally, we made continuous measurements of absorption and light scattering by aerosol particles. The vertical chemical composition gradients at the forest site have been discussed in a companion article (Journal of Geophysical Research-Atmospheres 108 (D18), 4591 (doi:4510.1029/2003JD003465)). In this article, we present the results of a source identification and quantitative apportionment study of the wet and dry season aerosols, including an apportionment of the measured scattering and absorption properties of the total aerosol in terms of the identified aerosol sources. Source apportionments (obtained from absolute principal component analysis) revealed that the wet and dry season aerosols contained the same three main components, but in different (absolute and relative) amounts: the wet season aerosol consisted mainly of a natural biogenic component, whereas pyrogenic aerosols dominated the dry season aerosol mass. The third component identified was soil dust, which was often internally mixed with the biomass-burning aerosol. All three components contributed significantly to light extinction during both seasons. At the pasture site, up to 47% of the light absorption was attributed to biogenic particles during the wet season, and up to 35% at the tower site during the wet-to-dry transition period. The results from the present study suggest that, in addition to pyrogenic particles, biogenic and soil dust aerosols must be

  2. Janus particles as artificial antigen-presenting cells for T cell activation.

    Science.gov (United States)

    Chen, Bo; Jia, Yilong; Gao, Yuan; Sanchez, Lucero; Anthony, Stephen M; Yu, Yan

    2014-01-01

    Here we show that the multifunctionality of Janus particles can be exploited for in vitro T cell activation. We engineer bifunctional Janus particles on which the spatial distribution of two ligands, anti-CD3 and fibronectin, mimics the "bull's eye" protein pattern formed in the membrane junction between a T cell and an antigen-presenting cell. Different levels of T cell activation can be achieved by simply switching the spatial distribution of the two ligands on the surfaces of the "bull's eye" particles. We find that the ligand pattern also affects clustering of intracellular proteins. This study demonstrates that anisotropic particles, such as Janus particles, can be developed as artificial antigen-presenting cells for modulating T cell activation.

  3. Nano-sensing of the orientation of fluorescing molecules with active coated nano-particles

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Ziolkowski, Richard W.

    2015-01-01

    The potential of using active coated nano-particles to determine the orientation of fluorescing molecules is reported. By treating each fluorescing molecule as an electric Hertzian dipole, single and multiple fluorescing molecules emitting coherently and incoherently in various orientations...... are considered in the presence of active coated nano-particles. It is demonstrated that in addition to offering a means to determine the orientation of a single molecule or the over-all orientation of the molecules surrounding it, the nature of the far-field response from the active coated nano-particles...

  4. Isotopic composition of high-activity particles released in the Chernobyl accident

    Energy Technology Data Exchange (ETDEWEB)

    Osuch, S.; Dabrowska, M.; Jaracz, P.; Kaczanowski, J.; Le Van Kho; Mirowski, S.; Piasecki, E.; Szeflinska, G.; Szeflinski, Z.; Tropilo, J.; (Warsaw Univ. (Poland))

    1989-11-01

    Gamma spectra were measured and activities of the detected isotopes were analyzed for 206 high-activity particles (hot particles, HPs) found in northeastern Poland after the Chernobyl accident. The isotopic composition of HPs observed in gamma-activity is compared with that of the general fallout and core inventory calculations. Particle formation and a process of depletion in Ru and Cs isotopes are discussed. On the basis of a search performed a year later, some comments on the behavior of HPs in the soil are made.

  5. T cell exhaustion characterized by compromised MHC class I and II restricted cytotoxic activity associates with acute B lymphoblastic leukemia relapse after allogeneic hematopoietic stem cell transplantation.

    Science.gov (United States)

    Liu, Long; Chang, Ying-Jun; Xu, Lan-Ping; Zhang, Xiao-Hui; Wang, Yu; Liu, Kai-Yan; Huang, Xiao-Jun

    2018-02-22

    Acute B lymphoblastic leukemia (B-ALL) relapse contributes predominantly to the mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the mechanism of B-ALL relapse after allo-HSCT remains unknown. The eradication of leukemia after allo-HSCT largely relies on graft-versus-leukemia (GVL) effects mediated by donor T cells. T cell exhaustion, characterized by the increased expression of inhibitory receptors and impaired function, may suppress GVL effects. In this study, we evaluated whether T cell exhaustion was involved in B-ALL relapse after allo-HSCT. The results showed that CD4 + and CD8 + T cells exhibited increased coexpression of PD-1 and Tim-3, and compromised proliferative capacity, cytokine production and cytotoxic potentials in relapsed patients. Additionally, T cells at the tumor site were more easily exhausted than T cells in the peripheral blood. Moreover, the reversal of T cell exhaustion might correlate with effective anti-leukemic responses after reinduction. These results suggested that T cell exhaustion was associated with B-ALL relapse after allo-HSCT as well as its treatment outcome. Copyright © 2017. Published by Elsevier Inc.

  6. The absorption of gases in aqueous activated carbon slurries enhanced by adsorbing or catalytic particles

    NARCIS (Netherlands)

    Holstvoogd, R.D.; van Swaaij, Willibrordus Petrus Maria; van Dierendonck, L.L.

    1988-01-01

    The enhanced absorption of gases in aqueous activated carbon slurries of fine particles is studied with an instationary absorption model taking into account the finite adsorption capacity of the carbon particles, and with a stationary geometrical model, which describes the absorption into a highly

  7. Hydrothermal synthesis of nanostructured TiO2 particles and characterization of their photocatalytic antimicrobial activity.

    Science.gov (United States)

    Erdural, Beril K; Yurum, Alp; Bakir, Ufuk; Karakas, Gurkan

    2008-02-01

    Nanostructured titania particles were synthesized by using hydrothermal processing and the photocatalytic antimicrobial activities were characterized. Both sol-gel synthesized and commercial TiO2 (anatase) samples were processed with two step hydrothermal treatments, under alkaline and neutral conditions. Scanning Electron Microscope (SEM) images showed that alkaline treatment yields nanofibers and lamellar structured particles from the commercial anatase and sol-gel synthesized samples respectively. Further treatment of nanofibers and nanostructured lamellar particles with distilled water results with crystal growth and the formation of nano structured bipyramidal crystalline particles. The photocatalytic antimicrobial activities of the samples were determined against Escherichia coil under irradiation. It was observed that the samples treated under alkaline conditions have improved activity than the original anatase samples. Limited activity and resulting time lag in bacterial inactivation were observed for hydrothermally treated samples with distilled water. However, a post treatment comprising the UV irradiation in aqueous conditions enhanced the photocatalytic activity.

  8. Parallel particle identification and separation for active optical sorting

    DEFF Research Database (Denmark)

    Perch-Nielsen, Ivan R.; Palima, Darwin; Dam, Jeppe Seidelin

    2009-01-01

    An instrument for rapidly and non-invasively sorting different cell specimens is a valuable tool in biological and medical research. Parallel identification of target specimens through image analysis can sort based on highly tuneable selection criteria and can enable high-speed optical sorting when...... matched with a rapidly reconfigurable optical sorting field. We demonstrate the potential of such a system using colloidal polystyrene microspheres. By combining machine vision with a parallel add-on optical manipulation scheme, we were able to move identified particles over a distance of several hundred...

  9. Effect of indirect non-thermal plasma on particle size distribution and composition of diesel engine particles

    Science.gov (United States)

    Linbo, GU; Yixi, CAI; Yunxi, SHI; Jing, WANG; Xiaoyu, PU; Jing, TIAN; Runlin, FAN

    2017-11-01

    To explore the effect of the gas source flow rate on the actual diesel exhaust particulate matter (PM), a test bench for diesel engine exhaust purification was constructed, using indirect non-thermal plasma technology. The effects of different gas source flow rates on the quantity concentration, composition, and apparent activation energy of PM were investigated, using an engine exhaust particle sizer and a thermo-gravimetric analyzer. The results show that when the gas source flow rate was large, not only the maximum peak quantity concentrations of particles had a large drop, but also the peak quantity concentrations shifted to smaller particle sizes from 100 nm to 80 nm. When the gas source flow rate was 10 L min-1, the total quantity concentration greatly decreased where the removal rate of particles was 79.2%, and the variation of the different mode particle proportion was obvious. Non-thermal plasma (NTP) improved the oxidation ability of volatile matter as well as that of solid carbon. However, the NTP gas source rate had little effects on oxidation activity of volatile matter, while it strongly influenced the oxidation activity of solid carbon. Considering the quantity concentration and oxidation activity of particles, a gas source flow rate of 10 L min-1 was more appropriate for the purification of particles.

  10. Impact of pectin esterification on the antimicrobial activity of nisin-loaded pectin particles.

    Science.gov (United States)

    Krivorotova, Tatjana; Staneviciene, Ramune; Luksa, Juliana; Serviene, Elena; Sereikaite, Jolanta

    2017-01-01

    The relationship between pectin structure and the antimicrobial activity of nisin-loaded pectin particles was examined. The antimicrobial activity of five different nisin-loaded pectin particles, i.e., nisin-loaded high methoxyl pectin, low methoxyl pectin, pectic acid, dodecyl pectin with 5.4 and 25% degree of substitution were tested in the pH range of 4.0-7.0 by agar-diffusion assay and agar plate count methods. It was found that the degree of esterification of carboxyl group of galacturonic acid in pectin molecule is important for the antimicrobial activity of nisin-loaded pectin particles. Nisin-loaded particles prepared using pectic acid or the pectin with low degree of esterification exhibit higher antimicrobial activity than nisin-loaded high methoxyl pectin particles. Pectins with free carboxyl groups or of low degree of esterification are the most suitable for particles preparation. Moreover, nisin-loaded pectin particles were active at close to neutral or neutral pH values. Therefore, they could be effectively applied for food preservation. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:245-251, 2017. © 2016 American Institute of Chemical Engineers.

  11. In situ structure and activity studies of an enzyme adsorbed on spectroscopically undetectable particles

    NARCIS (Netherlands)

    Koutsopoulos, S; Tjeerdsma, AM; Lieshout, JFT; van der Oost, J; Norde, W

    2005-01-01

    The structural characteristics and the activity of a hyperthermophilic endoglucanase were investigated upon adsorption. Silica (hydrophilic) and Teflon (hydrophobic) surfaces were selected for the study. The materials were specially designed so that the interaction of the particles with light was

  12. The Influence of Stirring upon the Adsorption of a Cationic Surfactant onto Activated Carbon Particles

    National Research Council Canada - National Science Library

    Stevenson, Paul; Shaw, Ryan; Tulloch, John; Evans, Geoffrey M

    2011-01-01

    The adsorption rate of the cationic surfactant cetyl trimethylammonium bromide (CTAB) onto particles of activated carbon has been determined from measurements of the changes in the conductivity of the supernatant solution...

  13. Engineering task plan for five portable exhausters

    Energy Technology Data Exchange (ETDEWEB)

    Rensink, G.E.

    1997-10-01

    Exhausters will be employed to ventilate certain single-shell tanks (SSTs) during salt well pumping campaigns. Active ventilation is necessary to reduce the potential flammable gas inventory (LANL 1996a) in the dome space that may accumulate during steady-state conditions or during/after postulated episodic gas release events. The tanks described in this plan support the activities required to fabricate and test three 500 cfm portable exhausters in the 200 W area shops, and to procure, design, fabricate and test two 1000 cfm units. Appropriate Notice of Construction (NOC) radiological and toxic air pollutant permits will be obtained for the portable exhausters. The portable exhauster design media to be employed to support this task was previously developed for the 241-A-101 exhauster. The same design as A101 will be fabricated with only minor improvements to the design based upon operator input/lessons learned. The safety authorization basis for this program effort will follow SAD 36 (LANL 1996b), and each tank will be reviewed against this SAD for changes or updates. The 1000 cfm units will be designed by the selected offsite contractor according to the specification requirements in KHC-S-O490. The offsite units have been specified to utilize as many of the same components as the 500 cfm units to ensure a more cost effective operation and maintenance through the reduction of spare parts and additional procedures.

  14. CATALYTIC REDUCTION TECHNIQUES FOR POST-COMBUSTION DIESEL EXHAUST EMISSIONS

    OpenAIRE

    KESKİN, Ahmet; EMİROĞLU, Alaattin Osman

    2016-01-01

    Stiff exhaust emission regulations set for limiting the air pollution caused by motor vehicles have oriented the producers and researchers to investigate new techniques to reduce exhaust emissions. The main pollutants caused by diesel engines are particle matters (PM), nitrogen oxides (NOx), hydrocarbons (HC), and carbon monoxides (CO). Among the preventive actions to keep the emissions caused by motor vehicles at a certain level are enhancing the fuel quality, preventing the pollutant format...

  15. Dynamics of a magnetic active Brownian particle under a uniform magnetic field

    Science.gov (United States)

    Vidal-Urquiza, Glenn C.; Córdova-Figueroa, Ubaldo M.

    2017-11-01

    The dynamics of a magnetic active Brownian particle undergoing three-dimensional Brownian motion, both translation and rotation, under the influence of a uniform magnetic field is investigated. The particle self-propels at a constant speed along its magnetic dipole moment, which reorients due to the interplay between Brownian and magnetic torques, quantified by the Langevin parameter α . In this work, the time-dependent active diffusivity and the crossover time (τcross)—from ballistic to diffusive regimes—are calculated through the time-dependent correlation function of the fluctuations of the propulsion direction. The results reveal that, for any value of α , the particle undergoes a directional (or ballistic) propulsive motion at very short times (t ≪τcross ). In this regime, the correlation function decreases linearly with time, and the active diffusivity increases with it. It the opposite time limit (t ≫τcross ), the particle moves in a purely diffusive regime with a correlation function that decays asymptotically to zero and an active diffusivity that reaches a constant value equal to the long-time active diffusivity of the particle. As expected in the absence of a magnetic field (α =0 ), the crossover time is equal to the characteristic time scale for rotational diffusion, τrot. In the presence of a magnetic field (α >0 ), the correlation function, the active diffusivity, and the crossover time decrease with increasing α . The magnetic field regulates the regimes of propulsion of the particle. Here, the field reduces the period of time at which the active particle undergoes a directional motion. Consequently, the active particle rapidly reaches a diffusive regime at τcross≪τrot . In the limit of weak fields (α ≪1 ), the crossover time decreases quadratically with α , while in the limit of strong fields (α ≫1 ) it decays asymptotically as α-1. The results are in excellent agreement with those obtained by Brownian dynamics

  16. Non-Exhaust PM10 and Road Dust

    OpenAIRE

    Lundberg, Joacim

    2018-01-01

    Non-exhaust PM10 is an issue in the urban environment linked to health issues. Emissions of non-exhaust PM10 is relatable to pavement properties. Also of importance is resuspension of road dust stored from surfaces. This depends on the traffic and metrological conditions. Given this, the purpose of the thesis was to give an overview limited to Sweden and the Nordic countries regarding non-exhaust PM10 emissions and road dust. The overview includes how particles are related to human health. Al...

  17. The Wonderful World of Active Many-Particle Systems

    Science.gov (United States)

    Helbing, Dirk

    Since the subject of traffic dynamics has captured the interest of physicists, many astonishing effects have been revealed and explained. Some of the questions now understood are the following: Why are vehicles sometimes stopped by so-called ``phantom traffic jams'', although they all like to drive fast? What are the mechanisms behind stop-and-go traffic? Why are there several different kinds of congestion, and how are they related? Why do most traffic jams occur considerably before the road capacity is reached? Can a temporary reduction of the traffic volume cause a lasting traffic jam? Why do pedestrians moving in opposite directions normally organize in lanes, while nervous crowds are ``freezing by heating''? Why do panicking pedestrians produce dangerous deadlocks? All these questions have been answered by applying and extending methods from statistical physics and non-linear dynamics to self-driven many-particle systems.

  18. Circulating factors induce coronary endothelial cell activation following exposure to inhaled diesel exhaust and nitrogen dioxide in humans: Evidence from a novel translational in vitro model**

    Science.gov (United States)

    The vascular toxicity of inhaled agents may be caused by soluble factors that are released into the systemic circulation. To confirm this in a straightforward manner, we obtained plasma from healthy human volunteers before and after exposure to diesel exhaust (DE) and nitrogen di...

  19. Frequency band analysis of muscle activation during cycling to exhaustion.DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n3p243

    Directory of Open Access Journals (Sweden)

    Marco Aurélio Vaz

    2012-05-01

    Full Text Available Lower limb muscles activation was assessed during cycling to exhaustion using frequency band analysis. Nine cyclists were evaluated in two days. On the first day, cyclists performed a maximal incremental cycling exercise to measure peak power output, which was used on the second day to define the workload for a constant load time to exhaustion cycling exercise (maximal aerobic power output from day 1. Muscle activation of vastus lateralis (VL, long head of biceps femoris (BF, lateral head of gastrocnemius (GL, and tibialis anterior (TA from the right lower limb was recorded during the time to exhaustion cycling exercise. A series of nine band-pass Butterworth digital filters was used to analyze muscle activity amplitude for each band. The overall amplitude of activation and the high and low frequency components were defined to assess the magnitude of fatigue effects on muscle activity via effect sizes. The profile of the overall muscle activation during the test was analyzed using a second order polynomial, and the variability of the overall bands was analyzed by the coefficient of variation for each muscle in each instant of the test. Substantial reduction in the high frequency components of VL and BF activation was observed. The overall and low frequency bands presented trivial to small changes for all muscles. High relationship between the second order polynomial fitting and muscle activity was found (R2 > 0.89 for all muscles. High variability (~25% was found for muscle activation at the four instants of the fatigue test. Changes in the spectral properties of the EMG signal were only substantial when extreme changes in fatigue state were induced.

  20. Interaction forces between waterborne bacteria and activated carbon particles

    NARCIS (Netherlands)

    Busscher, Henk J.; Dijkstra, Rene J. B.; Langworthy, Don E.; Collias, Dimitris I.; Bjorkquist, David W.; Mitchell, Michael D.; Van der Mei, Henny C.

    2008-01-01

    Activated carbons remove waterborne bacteria from potable water systems through attractive Lifshitz-van der Waals forces despite electrostatic repulsion between negatively charged cells and carbon surfaces. In this paper we quantify the interaction forces between bacteria with negatively and

  1. PHYSICAL AND NUMERICAL MODELING OF ASD EXHAUST DISPERSION AROUND HOUSES

    Science.gov (United States)

    The report discusses the use of a wind tunnel to physically model the dispersion of exhaust plumes from active soil depressurization (ASD) radon mitigation systems in houses. he testing studied the effects of exhaust location (grade level vs. above the eave), as house height, roo...

  2. High temperature sensors for exhaust diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Svenningstorp, Henrik

    2000-07-01

    One of the largest problems that we will have to deal with on this planet this millennium is to stop the pollution of our environment. In many of the ongoing works to reduce toxic emissions, gas sensors capable of enduring rough environments and high temperatures, would be a great tool. The different applications where sensors like this would be useful vary between everything from online measurement in the paper industry and food industry to measurement in the exhaust pipe of a car. In my project we have tested Schottky diodes and MlSiCFET sensor as gas sensors operating at high temperatures. The measurement condition in the exhaust pipe of a car is extremely tough, not only is the temperature high and the different gases quite harmful, there are also a lot of particles that can affect the sensors in an undesirable way. In my project we have been testing Schottky diodes and MlSiCFET sensors based on SiC as high temperature sensors, both in the laboratory with simulated exhaust and after a real engine. In this thesis we conclude that these sensors can work in the hostile environment of an engines exhaust. It is shown that when measuring in a gas mixture with a fixed I below one, where the I-value is controlled by the O{sub 2} concentration, a sensor with a catalytic gate metal as sensitive material respond more to the increased O{sub 2} concentration than the increased HC concentration when varying the two correspondingly. A number of different sensors have been tested in simulated exhaust towards NO{sub x}. It was shown that resistivity changes in the thin gate metal influenced the gas response. Tests have been performed where sensors were a part of a SCR system with promising results concerning NH{sub 3} sensitivity. With a working temperature of 300 deg C there is no contamination of the metal surface.

  3. Effective equilibrium states in mixtures of active particles driven by colored noise

    Science.gov (United States)

    Wittmann, René; Brader, J. M.; Sharma, A.; Marconi, U. Marini Bettolo

    2018-01-01

    We consider the steady-state behavior of pairs of active particles having different persistence times and diffusivities. To this purpose we employ the active Ornstein-Uhlenbeck model, where the particles are driven by colored noises with exponential correlation functions whose intensities and correlation times vary from species to species. By extending Fox's theory to many components, we derive by functional calculus an approximate Fokker-Planck equation for the configurational distribution function of the system. After illustrating the predicted distribution in the solvable case of two particles interacting via a harmonic potential, we consider systems of particles repelling through inverse power-law potentials. We compare the analytic predictions to computer simulations for such soft-repulsive interactions in one dimension and show that at linear order in the persistence times the theory is satisfactory. This work provides the toolbox to qualitatively describe many-body phenomena, such as demixing and depletion, by means of effective pair potentials.

  4. Controlling active self-assembly through broken particle-shape symmetry.

    Science.gov (United States)

    Wensink, H H; Kantsler, V; Goldstein, R E; Dunkel, J

    2014-01-01

    Many structural properties of conventional passive materials are known to arise from the symmetries of their microscopic constituents. By contrast, it is largely unclear how the interplay between particle shape and self-propulsion controls the meso- and macroscale behavior of active matter. Here we use large-scale simulations of homo- and heterogeneous self-propelled particle systems to identify generic effects of broken particle-shape symmetry on collective motion. We find that even small violations of fore-aft symmetry lead to fundamentally different collective behaviors, which may facilitate demixing of differently shaped species as well as the spontaneous formation of stable microrotors. These results suggest that variation of particle shape yields robust physical mechanisms to control self-assembly of active matter, with possibly profound implications for biology and materials design.

  5. Influence of layer eccentricity on the resonant properties of cylindrical active coated nano-particles

    DEFF Research Database (Denmark)

    Thorsen, R. O.; Arslanagic, Samel

    2015-01-01

    We report on the influence of the layer eccentricity on the resonant properties of active coated nano-particles made of a silver core and gain impregnated silica shell illuminated by a near-by magnetic line source. For a fixed over-all size of the particle, designs with small and large cores......, this being more profound for the larger core nano-particles. The present results are useful from a from a practical viewpoint since slight displacements of the centers of the core and shell parts in these configurations are likely to occur in standard fabrication processes....

  6. Impact of the Excitation Source and Plasmonic Material on Cylindrical Active Coated Nano-Particles

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Liu, Yan; Malureanu, Radu

    2011-01-01

    Electromagnetic properties of cylindrical active coated nano-particles comprised of a silica nano-cylinder core layered with a plasmonic concentric nano-shell are investigated for potential nano-sensor applications. Particular attention is devoted to the near-field properties of these particles......, as well as to their far-field radiation characteristics, in the presence of an electric or a magnetic line source. A constant frequency canonical gain model is used to account for the gain introduced in the dielectric part of the nano-particle, whereas three different plasmonic materials (silver, gold...

  7. Interrelationships between cellulase activity and cellulose particle morphology

    DEFF Research Database (Denmark)

    Olsen, Johan Pelck; Donohoe, Bryon S.; Borch, Kim

    2016-01-01

    It is well documented that the enzymatic hydrolysis of cellulose follows a reaction pattern where an initial phase of relatively high activity is followed by a gradual slow-down over the entire course of the reaction. This phenomenon is not readily explained by conventional factors like substrate...... depletion, product inhibition or enzyme instability. It has been suggested that the underlying reason for the loss of enzyme activity is connected to the heterogeneous structure of cellulose, but so far attempts to establish quantitative measures of such a correlation remain speculative. Here, we have...... on this observation we argue that cellulose structure, specifically surface area and roughness, plays a major role in the ubiquitous rate loss observed for cellulases....

  8. Asymmetric active nano-particles for directive near-field radiation

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Thorsen, Rasmus O.

    2016-01-01

    In this work, we demonstrate the potential of cylindrical active coated nano-particles with certain geometrical asymmetries for the creation of directive near-field radiation. The particles are excited by a near-by magnetic line source, and their performance characteristics are reported in terms...... of radiated power, near-field and power flow distributions as well as the far-field directivity....

  9. Active Particles Moving in Two-Dimensional Space with Constant Speed: Revisiting the Telegrapher's Equation

    OpenAIRE

    Sevilla, Francisco J.; Nava, Luis A. Gomez

    2014-01-01

    Starting from a Langevin description of active particles that move with constant speed in infinite two-dimensional space and its corresponding Fokker-Planck equation, we develop a systematic method that allows us to obtain the coarse-grained probability density of finding a particle at a given location and at a given time to arbitrary short time regimes. By going beyond the diffusive limit, we derive a novel generalization of the telegrapher's equation. Such generalization preserves the hyper...

  10. Particle size tailoring of ursolic acid nanosuspensions for improved anticancer activity by controlled antisolvent precipitation.

    Science.gov (United States)

    Wang, Yancai; Song, Ju; Chow, Shing Fung; Chow, Albert H L; Zheng, Ying

    2015-10-15

    The present study was aimed at tailoring the particle size of ursolic acid (UA) nanosuspension for improved anticancer activity. UA nanosuspensions were prepared by antisolvent precipitation using a four-stream multi-inlet vortex mixer (MIVM) under defined conditions of varying solvent composition, drug feeding concentration or stream flow rate. The resulting products were characterized for particle size and polydispersity. Two of the UA nanosuspensions with mean particle sizes of 100 and 300 nm were further assessed for their in-vitro activity against MCF-7 breast cancer cells using fluorescence microscopy with 4',6-diamidino-2-phenylindole (DAPI) staining, as well as flow cytometry with propidium (PI) staining and with double staining by fluorescein isothiocyanate. It was revealed that the solvent composition, drug feeding concentration and stream flow rate were critical parameters for particle size control of the UA nanosuspensions generated with the MIVM. Specifically, decreasing the UA feeding concentration or increasing the stream flow rate or ethanol content resulted in a reduction of particle size. Excellent reproducibility for nanosuspension production was demonstrated for the 100 and 300 nm UA preparations with a deviation of not more than 5% in particle size from the mean value of three independent batches. Fluorescence microscopy and flow cytometry revealed that these two different sized UA nanosuspensions, particularly the 300 nm sample, exhibited a higher anti-proliferation activity against the MCF-7 cells and afforded a larger population of these cells in both early and late apoptotic phases. In conclusion, MIVM is a robust and pragmatic tool for tailoring the particle size of the UA nanosuspension. Particle size appears to be a critical determinant of the anticancer activity of the UA nanoparticles. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Single-Particle Laboratory Studies of Heterogeneous H2O and HCl Processing on Clean and H2SO4-Coated Aluminum Oxide Particles

    Science.gov (United States)

    Hunter, A. J.; Sonnenfroh, D. M.; Rawlins, W. T.

    2001-12-01

    Aluminum oxide particles exhausted from solid rocket motors may affect tropospheric and stratospheric radiative balance through nucleation and growth of water ice clouds, both locally in launch corridors and globally. These particles also are active toward chemisorption of HCl and dissociative chemisorption of CFCs. Plume particle surfaces are likely to contain H2SO4, possibly altering their activities toward uptake and chemical processing of HCl and HNO3. We have investigated activities of different types of aluminum oxide particles for uptake of gas-phase H2O and HCl, using a single-particle electrodynamic levitation apparatus. The particle types investigated were clean and H2SO4-treated alpha-Al2O3 and gamma-Al2O3. We also investigated metastable Al2O3 particles formed by rapid cooling from molten particles in a shock tube, analogous to particle processing in a rocket exhaust nozzle. Particles were treated with H2SO4 by vapor deposition in an oven. The kinetic measurements consisted of independent, simultaneous observations of mass uptake and particle size increase upon exposure of single levitated particles to fixed concentrations of H2O or HCl in slowly flowing gas mixtures at 1 atm. Alpha and gamma Al2O3 were essentially inert toward H2O and HCl uptake, however they readily adsorbed monolayer-equivalent levels of H2SO4 vapor. H2SO4-coated and metastable particles were active toward H2O and HCl uptake. The measured uptake efficiencies imply fast reaction rates within rocket exhaust plumes, potentially leading to CCN behavior as well as heterogeneous chlorine activation by these particles. This research was supported by the Air Force Office of Scientific Research.

  12. Influence of adhesion to activated carbon particles on the viability of waterborne pathogenic bacteria under flow

    NARCIS (Netherlands)

    van der Mei, Henny C.; Atema-Smit, Jelly; Jager, Debbie; Langworthy, Don E.; Collias, Dimitris I.; Mitchell, Michael D.; Busscher, Henk J.

    2008-01-01

    In rural areas around the world, people often rely on water filtration plants using activated carbon particles for safe water supply. Depending on the carbon surface, adhering microorganisms die or grow to form a biofilm. Assays to assess the efficacy of activated carbons in bacterial removal do not

  13. Asian Dust Particles Induce Macrophage Inflammatory Responses via Mitogen-Activated Protein Kinase Activation and Reactive Oxygen Species Production

    Directory of Open Access Journals (Sweden)

    Kazuma Higashisaka

    2014-01-01

    Full Text Available Asian dust is a springtime meteorological phenomenon that originates in the deserts of China and Mongolia. The dust is carried by prevailing winds across East Asia where it causes serious health problems. Most of the information available on the impact of Asian dust on human health is based on epidemiological investigations, so from a biological standpoint little is known of its effects. To clarify the effects of Asian dust on human health, it is essential to assess inflammatory responses to the dust and to evaluate the involvement of these responses in the pathogenesis or aggravation of disease. Here, we investigated the induction of inflammatory responses by Asian dust particles in macrophages. Treatment with Asian dust particles induced greater production of inflammatory cytokines interleukin-6 and tumor necrosis factor-α (TNF-α compared with treatment with soil dust. Furthermore, a soil dust sample containing only particles ≤10 μm in diameter provoked a greater inflammatory response than soil dust samples containing particles >10 μm. In addition, Asian dust particles-induced TNF-α production was dependent on endocytosis, the production of reactive oxygen species, and the activation of nuclear factor-κB and mitogen-activated protein kinases. Together, these results suggest that Asian dust particles induce inflammatory disease through the activation of macrophages.

  14. Asian dust particles induce macrophage inflammatory responses via mitogen-activated protein kinase activation and reactive oxygen species production.

    Science.gov (United States)

    Higashisaka, Kazuma; Fujimura, Maho; Taira, Mayu; Yoshida, Tokuyuki; Tsunoda, Shin-ichi; Baba, Takashi; Yamaguchi, Nobuyasu; Nabeshi, Hiromi; Yoshikawa, Tomoaki; Nasu, Masao; Yoshioka, Yasuo; Tsutsumi, Yasuo

    2014-01-01

    Asian dust is a springtime meteorological phenomenon that originates in the deserts of China and Mongolia. The dust is carried by prevailing winds across East Asia where it causes serious health problems. Most of the information available on the impact of Asian dust on human health is based on epidemiological investigations, so from a biological standpoint little is known of its effects. To clarify the effects of Asian dust on human health, it is essential to assess inflammatory responses to the dust and to evaluate the involvement of these responses in the pathogenesis or aggravation of disease. Here, we investigated the induction of inflammatory responses by Asian dust particles in macrophages. Treatment with Asian dust particles induced greater production of inflammatory cytokines interleukin-6 and tumor necrosis factor- α (TNF- α ) compared with treatment with soil dust. Furthermore, a soil dust sample containing only particles ≤10  μ m in diameter provoked a greater inflammatory response than soil dust samples containing particles >10  μ m. In addition, Asian dust particles-induced TNF- α production was dependent on endocytosis, the production of reactive oxygen species, and the activation of nuclear factor- κ B and mitogen-activated protein kinases. Together, these results suggest that Asian dust particles induce inflammatory disease through the activation of macrophages.

  15. The effect of active fluctuations on the dynamics of particles, motors and hairpins

    CERN Document Server

    Vandebroek, Hans

    2016-01-01

    Inspired by recent experiments on the dynamics of particles and polymers in artificial cytoskeletons and in cells, we introduce a modified Langevin equation for a particle in an environment that is a viscoelastic medium and that is brought out of equilibrium by the action of active fluctuations caused by molecular motors. We show that within such a model, the motion of a free particle crosses over from superdiffusive to subdiffusive as observed for tracer particles in an {\\it in vitro} cytoskeleton or in a cell. We investigate the dynamics of a particle confined by a harmonic potential as a simple model for the motion of the tethered head of kinesin-1. We find that the probability that the head is close to its binding site on the microtubule can be enhanced by a factor of two due to active forces. Finally, we study the dynamics of a particle in a double well potential as a model for the dynamics of DNA-hairpins. We show that the active forces effectively lower the potential barrier between the two minima and ...

  16. Pre-activation of ice-nucleating particles by the pore condensation and freezing mechanism

    Directory of Open Access Journals (Sweden)

    R. Wagner

    2016-02-01

    Full Text Available In spite of the resurgence in ice nucleation research a comparatively small number of studies deal with the phenomenon of pre-activation in heterogeneous ice nucleation. Fifty years ago, it was shown that various mineral dust and volcanic ash particles can be pre-activated to become nuclei for ice crystal formation even at temperatures as high as 270–271 K. Pre-activation was achieved under ice-subsaturated conditions without any preceding macroscopic ice growth by just temporarily cooling the particles to temperatures below 228 K. A two-step mechanism involving capillary condensation of supercooled water and subsequent homogeneous freezing was proposed to account for the particles' enhanced ice nucleation ability at high temperatures. This work reinvestigates the efficiency of the proposed pre-activation mechanism in temperature-cycling experiments performed in a large cloud chamber with suspended particles. We find the efficiency to be highest for the clay mineral illite as well as for highly porous materials like zeolite and diatomaceous earth, whereas most aerosols generated from desert dust surface samples did not reveal a measurable pre-activation ability. The pre-activation efficiency is linked to particle pores in a certain size range. As estimated by model calculations, only pores with diameters between about 5 and 8 nm contribute to pre-activation under ice-subsaturated conditions. This range is set by a combination of requirements from the negative Kelvin effect for condensation and a critical size of ice embryos for ice nucleation and melting. In contrast to the early study, pre-activation is only observed for temperatures below 260 K. Above that threshold, the particles' improved ice nucleation ability disappears due to the melting of ice in the pores.

  17. Shape-dependent guidance of active Janus particles by chemically patterned surfaces

    Science.gov (United States)

    Uspal, W. E.; Popescu, M. N.; Tasinkevych, M.; Dietrich, S.

    2018-01-01

    Self-phoretic chemically active Janus particles move by inducing—via non-equilibrium chemical reactions occurring on their surfaces—changes in the chemical composition of the solution in which they are immersed. This process leads to gradients in chemical composition along the surface of the particle, as well as along any nearby boundaries, including solid walls. Chemical gradients along a wall can give rise to chemi-osmosis, i.e., the gradients drive surface flows which, in turn, drive flow in the volume of the solution. This bulk flow couples back to the particle, and thus contributes to its self-motility. Since chemi-osmosis strongly depends on the molecular interactions between the diffusing molecular species and the wall, the response flow induced and experienced by a particle encodes information about any chemical patterning of the wall. Here, we extend previous studies on self-phoresis of a sphere near a chemically patterned wall to the case of particles with rod-like, elongated shape. We focus our analysis on the new phenomenology potentially emerging from the coupling—which is inoperative for a spherical shape—of the elongated particle to the strain rate tensor of the chemi-osmotic flow. Via detailed numerical calculations, we show that the dynamics of a rod-like particle exhibits a novel ‘edge-following’ steady state: the particle translates along the edge of a chemical step at a steady distance from the step and with a steady orientation. Moreover, within a certain range of system parameters, the edge-following state co-exists with a ‘docking’ state (the particle stops at the step, oriented perpendicular to the step edge), i.e., a bistable dynamics occurs. These findings are rationalized as a consequence of the competition between the fluid vorticity and the rate of strain by using analytical theory based on the point-particle approximation which captures quasi-quantitatively the dynamics of the system.

  18. Effect of Pellet Boiler Exhaust on Secondary Organic Aerosol Formation from α-Pinene.

    Science.gov (United States)

    Kari, Eetu; Hao, Liqing; Yli-Pirilä, Pasi; Leskinen, Ari; Kortelainen, Miika; Grigonyte, Julija; Worsnop, Douglas R; Jokiniemi, Jorma; Sippula, Olli; Faiola, Celia L; Virtanen, Annele

    2017-02-07

    Interactions between anthropogenic and biogenic emissions, and implications for aerosol production, have raised particular scientific interest. Despite active research in this area, real anthropogenic emission sources have not been exploited for anthropogenic-biogenic interaction studies until now. This work examines these interactions using α-pinene and pellet boiler emissions as a model test system. The impact of pellet boiler emissions on secondary organic aerosol (SOA) formation from α-pinene photo-oxidation was studied under atmospherically relevant conditions in an environmental chamber. The aim of this study was to identify which of the major pellet exhaust components (including high nitrogen oxide (NOx), primary particles, or a combination of the two) affected SOA formation from α-pinene. Results demonstrated that high NOx concentrations emitted by the pellet boiler reduced SOA yields from α-pinene, whereas the chemical properties of the primary particles emitted by the pellet boiler had no effect on observed SOA yields. The maximum SOA yield of α-pinene in the presence of pellet boiler exhaust (under high-NOx conditions) was 18.7% and in the absence of pellet boiler exhaust (under low-NOx conditions) was 34.1%. The reduced SOA yield under high-NOx conditions was caused by changes in gas-phase chemistry that led to the formation of organonitrate compounds.

  19. Characterization of airborne particles generated from metal active gas welding process.

    Science.gov (United States)

    Guerreiro, C; Gomes, J F; Carvalho, P; Santos, T J G; Miranda, R M; Albuquerque, P

    2014-05-01

    This study is focused on the characterization of particles emitted in the metal active gas welding of carbon steel using mixture of Ar + CO2, and intends to analyze which are the main process parameters that influence the emission itself. It was found that the amount of emitted particles (measured by particle number and alveolar deposited surface area) are clearly dependent on the distance to the welding front and also on the main welding parameters, namely the current intensity and heat input in the welding process. The emission of airborne fine particles seems to increase with the current intensity as fume-formation rate does. When comparing the tested gas mixtures, higher emissions are observed for more oxidant mixtures, that is, mixtures with higher CO2 content, which result in higher arc stability. These mixtures originate higher concentrations of fine particles (as measured by number of particles by cm(3) of air) and higher values of alveolar deposited surface area of particles, thus resulting in a more severe worker's exposure.

  20. Green Synthesis of Smart Metal/Polymer Nanocomposite Particles and Their Tuneable Catalytic Activities

    Directory of Open Access Journals (Sweden)

    Noel Peter Bengzon Tan

    2016-03-01

    Full Text Available Herein we report a simple and green synthesis of smart Au and Ag@Au nanocomposite particles using poly(N-isopropylacrylamide/polyethyleneimine (PNIPAm/PEI core-shell microgels as dual reductant and templates in an aqueous system. The nanocomposite particles were synthesized through a spontaneous reduction of tetrachloroauric (III acid to gold nanoparticles at room temperature, and in situ encapsulation and stabilization of the resultant gold nanoparticles (AuNPs with amine-rich PEI shells. The preformed gold nanoparticles then acted as seed nanoparticles for further generation of Ag@Au bimetallic nanoparticles within the microgel templates at 60 °C. These nanocomposite particles were characterized by TEM, AFM, XPS, UV-vis spectroscopy, zeta-potential, and particle size analysis. The synergistic effects of the smart nanocomposite particles were studied via the reduction of p-nitrophenol to p-aminophenol. The catalytic performance of the bimetallic Ag@Au nanocomposite particles was 25-fold higher than that of the monometallic Au nanoparticles. Finally, the controllable catalytic activities of the Au@PNIPAm/PEI nanocomposite particles were demonstrated via tuning the solution pH and temperature.

  1. Charged Particle Detection using a CMOS Active Pixel Sensor

    CERN Document Server

    Matis, H S; Kleinfelder, S A; Rai, G; Retière, F; Ritter, H G; Singh, K; Wurzel, S E; Wieman, H H; Yamamoto, E

    2003-01-01

    Active Pixel Sensor (APS) technology has shown promise for next-generation vertex detectors. This paper discusses the design and testing of two generations of APS chips. Both are arrays of 128 by 128 pixels, each 20 by 20 micro-m. Each array is divided into sub-arrays in which different sensor structures (4 in the first version and 16 in the second) and/or readout circuits are employed. Measurements of several of these structures under Fe55 exposure are reported. The sensors have also been irradiated by 55 MeV protons to test for radiation damage. The radiation increased the noise and reduced the signal. The noise can be explained by shot noise from the increased leakage current and the reduction in signal is due to charge being trapped in the epi layer. Nevertheless, the radiation effect is small for the expected exposures at RHIC and RHIC II. Finally, we describe our concept for mechanically supporting a thin silicon wafer in an actual detector.

  2. A CMOS Active Pixel Sensor for Charged Particle Detection

    Energy Technology Data Exchange (ETDEWEB)

    Matis, Howard S.; Bieser, Fred; Kleinfelder, Stuart; Rai, Gulshan; Retiere, Fabrice; Ritter, Hans George; Singh, Kunal; Wurzel, Samuel E.; Wieman, Howard; Yamamoto, Eugene

    2002-12-02

    Active Pixel Sensor (APS) technology has shown promise for next-generation vertex detectors. This paper discusses the design and testing of two generations of APS chips. Both are arrays of 128 by 128 pixels, each 20 by 20 {micro}m. Each array is divided into sub-arrays in which different sensor structures (4 in the first version and 16 in the second) and/or readout circuits are employed. Measurements of several of these structures under Fe{sup 55} exposure are reported. The sensors have also been irradiated by 55 MeV protons to test for radiation damage. The radiation increased the noise and reduced the signal. The noise can be explained by shot noise from the increased leakage current and the reduction in signal is due to charge being trapped in the epi layer. Nevertheless, the radiation effect is small for the expected exposures at RHIC and RHIC II. Finally, we describe our concept for mechanically supporting a thin silicon wafer in an actual detector.

  3. A single-source hydrothermal route to synthesize porous hematite particles and their photocatalytic activity.

    Science.gov (United States)

    He, Xing; Zhu, Yufang

    2012-09-01

    In this work, we have successfully synthesized porous hematite (alpha-Fe2O3) particles with reasonable surface area by the hydrothermal treatment of iron(II) D-gluconate aqueous solution and the calcination at 550 degrees C. These porous alpha-Fe2O3 particles were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microcopy and N2 adsorption-desorption technique. The results indicated that these alpha-Fe2O3 particles have high porosity at mesoscale, and the specific surface area can reach 35.1 m2/g. The evaluation of photocatalytic activities of porous alpha-Fe2O3 particles for photocatalytic degradation of rhodamine B (RhB) aqueous solution in the presence of H2O2, indicated that porous alpha-Fe2O3 particles exhibit good visible-light photocatalytic activities. Therefore, the prepared porous alpha-Fe2O3 particles are of great interest in photocataytic degradation of dyes.

  4. An experimental study on the effects of exhaust gas on spruce (Picea abies L. Karst.)

    Energy Technology Data Exchange (ETDEWEB)

    Hautala, E.L.; Holopainen, J.; Kaerenlampi, L. [Kuopio Univ. (Finland). Dept. of Ecology and Environmental Science; Surakka, J.; Ruuskanen, J. [Kuopio Univ. (Finland). Dept. of Environmental Sciences

    1995-12-31

    Motor vehicle exhausts are significant contributors to air pollution. Besides fine particles and inorganic gases, like CO, SO{sub 2} and NO{sub x}, exhaust gas contains a large group of aromatic hydrocarbon compounds, many of which are phytotoxic. In field studies, exhausts are found to have both direct and indirect harmful effects on roadside plants. However, only few experimental studies have been made about the effects of exhaust gas emissions on coniferous trees. The aim of this study was to survey the effects of exhausts on spruce (Picea abies L. Karst.) in standardized conditions. The concentrations of major exhaust gas components in the chamber atmosphere were detected simultaneously. The effects of exhaust on epistomatal waxes of first-year spruce needles are described. (author)

  5. A phenomenological particle-based platelet model for simulating filopodia formation during early activation.

    Science.gov (United States)

    Pothapragada, Seetha; Zhang, Peng; Sheriff, Jawaad; Livelli, Mark; Slepian, Marvin J; Deng, Yuefan; Bluestein, Danny

    2015-03-01

    We developed a phenomenological three-dimensional platelet model to characterize the filopodia formation observed during early stage platelet activation. Departing from continuum mechanics based approaches, this coarse-grained molecular dynamics (CGMD) particle-based model can deform to emulate the complex shape change and filopodia formation that platelets undergo during activation. The platelet peripheral zone is modeled with a two-layer homogeneous elastic structure represented by spring-connected particles. The structural zone is represented by a cytoskeletal assembly comprising of a filamentous core and filament bundles supporting the platelet's discoid shape, also modeled by spring-connected particles. The interior organelle zone is modeled by homogeneous cytoplasm particles that facilitate the platelet deformation. Nonbonded interactions among the discrete particles of the membrane, the cytoskeletal assembly, and the cytoplasm are described using the Lennard-Jones potential with empirical constants. By exploring the parameter space of this CGMD model, we have successfully simulated the dynamics of varied filopodia formations. Comparative analyses of length and thickness of filopodia show that our numerical simulations are in agreement with experimental measurements of flow-induced activated platelets. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Many-body microhydrodynamics of colloidal particles with active boundary layers

    Science.gov (United States)

    Singh, Rajesh; Ghose, Somdeb; Adhikari, R.

    2015-06-01

    Colloidal particles with active boundary layers—regions surrounding the particles where non-equilibrium processes produce large velocity gradients—are common in many physical, chemical and biological contexts. The velocity or stress at the edge of the boundary layer determines the exterior fluid flow and, hence, the many-body interparticle hydrodynamic interaction. Here, we present a method to compute the many-body hydrodynamic interaction between N spherical active particles induced by their exterior microhydrodynamic flow. First, we use a boundary integral representation of the Stokes equation to eliminate bulk fluid degrees of freedom. Then, we expand the boundary velocities and tractions of the integral representation in an infinite-dimensional basis of tensorial spherical harmonics and, on enforcing boundary conditions in a weak sense on the surface of each particle, obtain a system of linear algebraic equations for the unknown expansion coefficients. The truncation of the infinite series, fixed by the degree of accuracy required, yields a finite linear system that can be solved accurately and efficiently by iterative methods. The solution linearly relates the unknown rigid body motion to the known values of the expansion coefficients, motivating the introduction of propulsion matrices. These matrices completely characterize hydrodynamic interactions in active suspensions just as mobility matrices completely characterize hydrodynamic interactions in passive suspensions. The reduction in the dimensionality of the problem, from a three-dimensional partial differential equation to a two-dimensional integral equation, allows for dynamic simulations of hundreds of thousands of active particles on multi-core computational architectures. In our simulation of 104 active colloidal particle in a harmonic trap, we find that the necessary and sufficient ingredients to obtain steady-state convective currents, the so-called ‘self-assembled pump’, are (a) one

  7. Correlating particle size and shape of supported Ru/gamma-Al2O3 catalysts with NH3 decomposition activity.

    Science.gov (United States)

    Karim, Ayman M; Prasad, Vinay; Mpourmpakis, Giannis; Lonergan, William W; Frenkel, Anatoly I; Chen, Jingguang G; Vlachos, Dionisios G

    2009-09-02

    While ammonia synthesis and decomposition on Ru are known to be structure-sensitive reactions, the effect of particle shape on controlling the particle size giving maximum turnover frequency (TOF) is not understood. By controlling the catalyst pretreatment conditions, we have varied the particle size and shape of supported Ru/gamma-Al(2)O(3) catalysts. The Ru particle shape was reconstructed by combining microscopy, chemisorption, and extended X-ray absorption fine structure (EXAFS) techniques. We show that the particle shape can change from a round one, for smaller particles, to an elongated, flat one, for larger particles, with suitable pretreatment. Density functional theory calculations suggest that the calcination most likely leads to planar structures. We show for the first time that the number of active (here B(5)) sites is highly dependent on particle shape and increases with particle size up to 7 nm for flat nanoparticles. The maximum TOF (based on total exposed Ru atoms) and number of active (B(5)) sites occur at approximately 7 nm for elongated nanoparticles compared to at approximately 1.8-3 nm for hemispherical nanoparticles. A complete, first-principles based microkinetic model is constructed that can quantitatively describe for the first time the effect of varying particle size and shape on Ru activity and provide further support of the characterization results. In very small nanoparticles, particle size polydispersity (due to the presence of larger particles) appears to be responsible for the observed activity.

  8. Acute effects of kinesio taping on knee extensor peak torque and electromyographic activity after exhaustive isometric knee extension in healthy young adults.

    Science.gov (United States)

    Yeung, Simon S; Yeung, Ella W; Sakunkaruna, Yosawin; Mingsoongnern, Sutida; Hung, Wing Y; Fan, Yun L; Iao, Heng C

    2015-05-01

    To evaluate the effect of Kinesio Tex tape and its method of application, Kinesio Taping (KT) on knee extensor performance before and after an exhaustive isometric knee extension exercise. Single-blinded, randomized control trial. Centre for Sports Training and Rehabilitation at The Hong Kong Polytechnic University. Twenty-six healthy volunteers with no history of knee injuries. Subjects were randomized to either the KT or sham taping group. The effects of KT on the neuromuscular performance of the knee extensors were measured before and after KT application, and immediately and 5 and 10 minutes after an exhaustive isometric knee extension exercise. Within-group analyses revealed a significant effect of time on the peak torque in isometric knee extension (F2.73,65.44 = 24.5, P Kinesio taping is commonly seen in the sports arena. The popularity is presumably due to the general belief in its injury prevention and enhancement of muscle performance. The results of the present findings suggested that KT shortens the time to reach peak torque generation. Aside from this, there is no other significant positive effect on muscle performance. Further investigation on the effects of KT on muscle performance is warranted.

  9. Cloud droplet activation of mixed organic-sulfate particles produced by the photooxidation of isoprene

    NARCIS (Netherlands)

    King, S.M.; Rosenoern, T.; Shilling, J.E.; Chen, Q.; Wang, Z.; Biskos, G.; McKinney, K.A.; Pöschl, U.; Martin, S.T.

    2010-01-01

    The cloud condensation nuclei (CCN) properties of ammonium sulfate particles mixed with organic material condensed during the hydroxyl-radical-initiated photooxidation of isoprene (C5H8) were investigated in the continuous-flow Harvard Environmental Chamber. CCN activation curves were measured for

  10. Spherical active coated nano-particles – impact of the electric Hertzian dipole orientation

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Mostafavi, M.; Malureanu, Radu

    2011-01-01

    Spherical active coated nano-particles comprised of a silica nano-cylinder core covered with a plasmonic nano-shell are investigated with regard to their near- and far-field properties. The source of excitation is taken to be that of a tangential or a radial electric Hertizan dipole while three...

  11. Investigating primary marine aerosol properties: CCN activity of sea salt and mixed inorganic-organic particles

    NARCIS (Netherlands)

    King, S.M.; Butcher, A.C.; Rosenoern, T.; Coz, E.; Lieke, K.I.; Leeuw, G. de; Nilsson, E.D.; Bilde, M.

    2012-01-01

    Sea spray particles ejected as a result of bubbles bursting from artificial seawater containing salt and organic matter in a stainless steel tank were sampled for size distribution, morphology, and cloud condensation nucleus (CCN) activity. Bubbles were generated either by aeration through a

  12. Quantitative structure-activity relationships for green algae growth inhibition by polymer particles.

    NARCIS (Netherlands)

    Nolte, Tom M; Peijnenburg, Willie J G M; Hendriks, A Jan; van de Meent, Dik

    After use and disposal of chemical products, many types of polymer particles end up in the aquatic environment with potential toxic effects to primary producers like green algae. In this study, we have developed Quantitative Structure-Activity Relationships (QSARs) for a set of highly structural

  13. Personal exposure to ultrafine particles: the influence of time-activity patterns.

    Science.gov (United States)

    Buonanno, G; Stabile, L; Morawska, L

    2014-01-15

    Exposure to ultrafine particles (UFPs) is deemed to be a major risk affecting human health. Therefore, airborne particle studies were performed in the recent years to evaluate the most critical micro-environments, as well as identifying the main UFP sources. Nonetheless, in order to properly evaluate the UFP exposure, personal monitoring is required as the only way to relate particle exposure levels to the activities performed and micro-environments visited. To this purpose, in the present work, the results of experimental analysis aimed at showing the effect of the time-activity patterns on UFP personal exposure are reported. In particular, 24 non-smoking couples (12 during winter and summer time, respectively), comprised of a man who worked full-time and a woman who was a homemaker, were analyzed using personal particle counter and GPS monitors. Each couple was investigated for a 48-h period, during which they also filled out a diary reporting the daily activities performed. Time activity patterns, particle number concentration exposure and the related dose received by the participants, in terms of particle alveolar-deposited surface area, were measured. The average exposure to particle number concentration was higher for women during both summer and winter (Summer: women 1.8 × 10(4) part. cm(-3); men 9.2 × 10(3) part. cm(-3); Winter: women 2.9 × 10(4) part. cm(-3); men 1.3 × 10(4) part. cm(-3)), which was likely due to the time spent undertaking cooking activities. Staying indoors after cooking also led to higher alveolar-deposited surface area dose for both women and men during the winter time (9.12 × 10(2) and 6.33 × 10(2) mm(2), respectively), when indoor ventilation was greatly reduced. The effect of cooking activities was also detected in terms of women's dose intensity (dose per unit time), being 8.6 and 6.6 in winter and summer, respectively. On the contrary, the highest dose intensity activity for men was time spent using transportation (2.8 in

  14. Effects of gaseous sulphuric acid on diesel exhaust nanoparticle formation and characteristics.

    Science.gov (United States)

    Rönkkö, Topi; Lähde, Tero; Heikkilä, Juha; Pirjola, Liisa; Bauschke, Ulrike; Arnold, Frank; Schlager, Hans; Rothe, Dieter; Yli-Ojanperä, Jaakko; Keskinen, Jorma

    2013-10-15

    Diesel exhaust gaseous sulphuric acid (GSA) concentrations and particle size distributions, concentrations, and volatility were studied at four driving conditions with a heavy duty diesel engine equipped with oxidative exhaust after-treatment. Low sulfur fuel and lubricant oil were used in the study. The concentration of the exhaust GSA was observed to vary depending on the engine driving history and load. The GSA affected the volatile particle fraction at high engine loads; higher GSA mole fraction was followed by an increase in volatile nucleation particle concentration and size as well as increase of size of particles possessing nonvolatile core. The GSA did not affect the number of nonvolatile particles. At low and medium loads, the exhaust GSA concentration was low and any GSA driven changes in particle population were not observed. Results show that during the exhaust cooling and dilution processes, besides critical in volatile nucleation particle formation, GSA can change the characteristics of all nucleation mode particles. Results show the dual nature of the nucleation mode particles so that the nucleation mode can include simultaneously volatile and nonvolatile particles, and fulfill the previous results for the nucleation mode formation, especially related to the role of GSA in formation processes.

  15. Aircraft exhaust sulfur emissions

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.C.; Anderson, M.R.; Miake-Lye, R.C.; Kolb, C.E. [Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics; Sorokin, A.A.; Buriko, Y.I. [Scientific Research Center `Ecolen`, Moscow (Russian Federation)

    1997-12-31

    The extent to which fuel sulfur is converted to SO{sub 3} during combustion and the subsequent turbine flow in supersonic and subsonic aircraft engines is estimated numerically. The analysis is based on: a flamelet model with non-equilibrium sulfur chemistry for the combustor, and a one-dimensional, two-stream model with finite rate chemical kinetics for the turbine. The results indicate that between 2% and 10% of the fuel sulfur is emitted as SO{sub 3}. It is also shown that, for a high fuel sulfur mass loading, conversion in the turbine is limited by the level of atomic oxygen at the combustor exit, leading to higher SO{sub 2} oxidation efficiency at lower fuel sulfur loadings. While SO{sub 2} and SO{sub 3} are the primary oxidation products, the model results further indicate H{sub 2}SO{sub 4} levels on the order of 0.1 ppm for supersonic expansions through a divergent nozzle. This source of fully oxidized S(6) (SO{sub 3} + H{sub 2}SO{sub 4}) exceeds previously calculated S(6) levels due to oxidation of SO{sub 2} by OH in the exhaust plume outside the engine nozzle. (author) 26 refs.

  16. Redox activity and chemical interactions of metal oxide nano- and micro-particles with dithiothreitol (DTT).

    Science.gov (United States)

    Nicolas, Johny; Jaafar, Malek; Sepetdjian, Elizabeth; Saad, Walid; Sioutas, Constantinos; Shihadeh, Alan; Saliba, Najat A

    2015-11-01

    The wide application and production of nanotechnology have increased the interest in studying the toxicity of nano- and micro-sized particles escaping into air from various aspects of the production process. Metal oxides (MOs) are one particular class of particles that exist abundantly in ambient PM. Studies show an emphasis on biological mechanisms by which inhalation exposure to MOs leads to disease. However, different biological assays provide different redox activity rankings making it difficult to assess the contributions of various MOs to measures of aggregate toxicity in multi-pollutant systems such as ambient PM. Therefore, research to evaluate the chemical interaction between these particles and molecules that are relevant to cellular redox activity can help in establishing indicators of reactivity. In particular, this study assesses the redox activity of six MOs mainly emitted from anthropogenic industrial activities using the dithiothreitol (DTT) assay. DTT is commonly used in acellular assays due to its analogous structure to cellular glutathione. The structural and chemical behaviors between active MOs and DTT were elucidated using FTIR, NMR, and BET methods. The results indicate that the health risk (redox activity) associated with MOs is mainly a function of their surface reactivity demonstrated by the ability of the oxidized (S-H) bond in DTT to form a stable bond with the MO surface.

  17. Nonequilibrium mode-coupling theory for dense active systems of self-propelled particles.

    Science.gov (United States)

    Nandi, Saroj Kumar; Gov, Nir S

    2017-10-25

    The physics of active systems of self-propelled particles, in the regime of a dense liquid state, is an open puzzle of great current interest, both for statistical physics and because such systems appear in many biological contexts. We develop a nonequilibrium mode-coupling theory (MCT) for such systems, where activity is included as a colored noise with the particles having a self-propulsion force f0 and a persistence time τp. Using the extended MCT and a generalized fluctuation-dissipation theorem, we calculate the effective temperature Teff of the active fluid. The nonequilibrium nature of the systems is manifested through a time-dependent Teff that approaches a constant in the long-time limit, which depends on the activity parameters f0 and τp. We find, phenomenologically, that this long-time limit is captured by the potential energy of a single, trapped active particle (STAP). Through a scaling analysis close to the MCT glass transition point, we show that τα, the α-relaxation time, behaves as τα ∼ f0(-2γ), where γ = 1.74 is the MCT exponent for the passive system. τα may increase or decrease as a function of τp depending on the type of active force correlations, but the behavior is always governed by the same value of the exponent γ. Comparison with the numerical solution of the nonequilibrium MCT and simulation results give excellent agreement with scaling analysis.

  18. Rectified transport of chiral active particles in the two-dimensional channel with varied upper wall

    Science.gov (United States)

    Huang, Xiao-qun; An, Meng

    2018-02-01

    Rectified transport of chiral self-propelled particles is numerically investigated in a two-dimensional channel with varied upper wall. Due to the chirality of active particles, the transversal asymmetry can break the symmetry of the system and induce a longitudinal net transport. It is found that the variation of the channel walls can strongly affect the rectified transport. There exist optimal values of the parameters (the variation parameter, the self-propelled velocity, the angular velocity, and the translational diffusion) at which the scaled average velocity takes its maximal value.

  19. Turbidimetric method for evaluation of photocatalytic activities of suspended fine particles

    Directory of Open Access Journals (Sweden)

    Hideki Aoyagi

    2010-10-01

    Full Text Available Hideki Aoyagi1, Katsumi Yabusaki21Life Science and Bioengineering, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan; 2Electronics and Optics Research Laboratory, Kowa Ltd, Chofugaoka, Chofu City, Tokyo, JapanAbstract: A spectrophotometer with special cuvette was developed for evaluating the photocatalytic activities of suspended fine particles. The spectrophotometer can continuously irradiate UV light using LED to the sample solution, and changes in the absorbance at 664 nm during photocatalytic degradation of methylene blue (MB were monitored continuously. From the onset of MB degradation, the absorbance decreased and reached a steady value at the end of the reaction. This process was expressed by first order kinetics and the photocatalytic activities of various fine particles could be evaluated quantitatively based on the reaction rate constant (k. The effect of photocatalysis using various TiO2 fine particles on the physiological activities of Euglena gracilis was related with k value.Keywords: photocatalyst, fine nano sized particles, specialized spectrophotometer, Euglena gracilis, rate constant

  20. Redox activity of urban quasi-ultrafine particles from primary and secondary sources

    Science.gov (United States)

    Verma, Vishal; Ning, Zhi; Cho, Arthur K.; Schauer, James J.; Shafer, Martin M.; Sioutas, Constantinos

    2009-12-01

    To characterize the redox activity profiles of atmospheric aerosols from primary (traffic) and secondary photochemical sources, ambient quasi-ultrafine particles were collected near downtown Los Angeles in two different time periods - morning (6:00-9:00 PDT) and afternoon (11:00-14:00 PDT) in the summer of 2008. Detailed chemical analysis of the collected samples, including water-soluble elements, inorganic ions, organic species and water soluble organic carbon (WSOC) was conducted and redox activity of the samples was measured by two different assays: the dithiothreitol (DTT) and the macrophage reactive oxygen species (ROS) assays. Tracers of secondary photochemical reactions, such as sulfate and organic acids were higher (2.1 ± 0.6 times for sulfate, and up to 3 times for the organic acids) in the afternoon period. WSOC was also elevated by 2.5 ± 0.9 times in the afternoon period due to photo-oxidation of primary particles during atmospheric aging. Redox activity measured by the DTT assay was considerably higher for the samples collected during the afternoon; on the other hand, diurnal trends in the ROS-based activity were not consistent between the morning and afternoon periods. A linear regression between redox activity and various PM chemical constituents showed that the DTT assay was highly correlated with WSOC ( R2 = 0.80), while ROS activity was associated mostly with water soluble transition metals (Vanadium, Nickel and Cadmium; R2 > 0.70). The DTT and ROS assays, which are based on the generation of different oxidizing species by chemical PM constituents, provide important information for elucidating the health risks related to PM exposure from different sources. Thus, both primary and secondary particles possess high redox activity; however, photochemical transformations of primary emissions with atmospheric aging enhance the toxicological potency of primary particles in terms of generating oxidative stress and leading to subsequent damage in cells.

  1. Relating particle hygroscopicity and CCN activity to chemical composition during the HCCT-2010 field campaign

    Directory of Open Access Journals (Sweden)

    Z. J. Wu

    2013-08-01

    Full Text Available Particle hygroscopic growth at 90% RH (relative humidity, cloud condensation nuclei (CCN activity, and size-resolved chemical composition were concurrently measured in the Thüringer Wald mid-level mountain range in central Germany in the fall of 2010. The median hygroscopicity parameter values, κ, of 50, 75, 100, 150, 200, and 250 nm particles derived from hygroscopicity measurements are respectively 0.14, 0.14, 0.17, 0.21, 0.24, and 0.28 during the sampling period. The closure between HTDMA (Hygroscopicity Tandem Differential Mobility Analyzers-measured (κHTDMA and chemical composition-derived (κchem hygroscopicity parameters was performed based on the Zdanovskii–Stokes–Robinson (ZSR mixing rule. Using size-averaged chemical composition, the κ values are substantially overpredicted (30 and 40% for 150 and 100 nm particles. Introducing size-resolved chemical composition substantially improved closure. We found that the evaporation of NH4NO3, which may happen in a HTDMA system, could lead to a discrepancy in predicted and measured particle hygroscopic growth. The hygroscopic parameter of the organic fraction, κorg, is positively correlated with the O : C ratio (κorg = 0.19 × (O : C − 0.03. Such correlation is helpful to define the κorg value in the closure study. κ derived from CCN measurement was around 30% (varied with particle diameters higher than that determined from particle hygroscopic growth measurements (here, hydrophilic mode is considered only. This difference might be explained by the surface tension effects, solution non-ideality, gas-particle partitioning of semivolatile compounds, and the partial solubility of constituents or non-dissolved particle matter. Therefore, extrapolating from HTDMA data to properties at the point of activation should be done with great care. Finally, closure study between CCNc (cloud condensation nucleus counter-measured (κCCN and chemical composition (κCCN, chem was performed using CCNc

  2. Thermal stability analysis of particles incorporated in cirrus crystals and of non-activated particles in between the cirrus crystals: comparing clean and polluted air masses

    Directory of Open Access Journals (Sweden)

    M. Seifert

    2004-01-01

    Full Text Available A thermal volatility technique is used to provide indirect information about the chemical composition of the aerosol involved in cirrus cloud formation. The fraction of particles that disappears after being heated to 125°C is termed volatile and the fraction that disappears between 125 and 250°C is termed semi-volatile. Particles that still remain after being heated to 250°C make up the non-volatile fraction. The thermal composition of residual particles remaining from evaporated cirrus crystals is presented and compared to interstitial aerosol particles (non-activated particles in between the cirrus crystals for two temperature regimes (cold: T< -38°C, warm: -38≤T< -23°C, based on in-situ observations. The observations were conducted in cirrus clouds in the Southern Hemisphere (SH and Northern Hemisphere (NH midlatitudes during the INCA project. In the cold temperature regime, the non-volatile fraction of the residual particles was typically in the range 10 to 30% in the NH and 30 to 40% in the SH. In the warm temperature regime, the non-volatile residual fraction was typically 10 to 30% (NH and 20 to 40% (SH. At high crystal number densities the non-volatile fraction in both temperature regimes was even higher: in the range of 30 to 40% (NH and 40 to 50% (SH. The semi-volatile fraction was typically less than 10% in both hemispheres, causing the volatile fraction to essentially be a complement to the non-volatile fraction. In terms of the fractioning into the three types of particles, the SH cold case is clearly different compared to the other three cases (the two warm cases and the cold NH case, which share many features. In the NH data the distribution of different particle types does not seem to be temperature dependent. In all the cases, the non-volatile fraction is enriched in the residual particles compared to the fractions observed for the interstitial particles. This enrichment corresponds to about 15 (NH and 30 (SH percent

  3. Diesel exhaust induced pulmonary and cardiovascular impairment: The role of hypertension intervention

    Energy Technology Data Exchange (ETDEWEB)

    Kodavanti, Urmila P., E-mail: kodavanti.urmila@epa.gov [Environmental Public Health Division, National Health and Environmental Effects Research Laboratory (NHEERL), Office of Research and Development (ORD), U.S. Environmental Protection Agency - EPA, Research Triangle Park, NC 27711 (United States); Thomas, Ronald F.; Ledbetter, Allen D.; Schladweiler, Mette C.; Bass, Virginia; Krantz, Q. Todd; King, Charly [Environmental Public Health Division, National Health and Environmental Effects Research Laboratory (NHEERL), Office of Research and Development (ORD), U.S. Environmental Protection Agency - EPA, Research Triangle Park, NC 27711 (United States); Nyska, Abraham [Tel Aviv University, Tel Aviv (Israel); Richards, Judy E. [Environmental Public Health Division, National Health and Environmental Effects Research Laboratory (NHEERL), Office of Research and Development (ORD), U.S. Environmental Protection Agency - EPA, Research Triangle Park, NC 27711 (United States); Andrews, Debora [Research Core Unit, NHEERL, ORD, U.S. EPA, Research Triangle Park, NC 27711 (United States); Gilmour, M. Ian [Environmental Public Health Division, National Health and Environmental Effects Research Laboratory (NHEERL), Office of Research and Development (ORD), U.S. Environmental Protection Agency - EPA, Research Triangle Park, NC 27711 (United States)

    2013-04-15

    Exposure to diesel exhaust (DE) and associated gases is linked to cardiovascular impairments; however, the susceptibility of hypertensive individuals is poorly understood. The objectives of this study were (1) to determine cardiopulmonary effects of gas-phase versus whole-DE and (2) to examine the contribution of systemic hypertension in pulmonary and cardiovascular effects. Male Wistar Kyoto (WKY) rats were treated with hydralazine to reduce blood pressure (BP) or L-NAME to increase BP. Spontaneously hypertensive (SH) rats were treated with hydralazine to reduce BP. Control and drug-pretreated rats were exposed to air, particle-filtered exhaust (gas), or whole DE (1500 μg/m{sup 3}), 4 h/day for 2 days or 5 days/week for 4 weeks. Acute and 4-week gas and DE exposures increased neutrophils and γ-glutamyl transferase (γ-GT) activity in lavage fluid of WKY and SH rats. DE (4 weeks) caused pulmonary albumin leakage and inflammation in SH rats. Two-day DE increased serum fatty acid binding protein-3 (FABP-3) in WKY. Marked increases occurred in aortic mRNA after 4-week DE in SH (eNOS, TF, tPA, TNF-α, MMP-2, RAGE, and HMGB-1). Hydralazine decreased BP in SH while L-NAME tended to increase BP in WKY; however, neither changed inflammation nor BALF γ-GT. DE-induced and baseline BALF albumin leakage was reduced by hydralazine in SH rats and increased by L-NAME in WKY rats. Hydralazine pretreatment reversed DE-induced TF, tPA, TNF-α, and MMP-2 expression but not eNOS, RAGE, and HMGB-1. ET-1 was decreased by HYD. In conclusion, antihypertensive drug treatment reduces gas and DE-induced pulmonary protein leakage and expression of vascular atherogenic markers. - Highlights: ► Acute diesel exhaust exposure induces pulmonary inflammation in healthy rats. ► In hypertensive rats diesel exhaust effects are seen only after long term exposure. ► Normalizing blood pressure reverses lung protein leakage caused by diesel exhaust. ► Normalizing blood pressure reverses

  4. Monolithic ionizing particle detector based on active matrix of functionally integrated structures

    Energy Technology Data Exchange (ETDEWEB)

    Murashev, V.N. [National University of Science and Technology “MISIS” (Russian Federation); Legotin, S.A., E-mail: serlego@mail.ru [National University of Science and Technology “MISIS” (Russian Federation); Karmanov, D.E. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics (MSU SINP) (Russian Federation); Baryshnikov, F.M.; Didenko, S.I. [National University of Science and Technology “MISIS” (Russian Federation)

    2014-02-15

    Highlights: • A new type of monolithic silicon position detector is presented. • An operating principle, design and technology of the detector are described. • Calculated estimations of the detecting efficiency are carried out. • Experimental results of alpha-particle and electron detection are shown. -- Abstract: An operating principle, design and technology of a new type of the monolithic silicon position detector (MSPD) for registration of ionizing particles and photons are described. The detector represents a specialized monolithic silicon VLSI that contains a two-dimensional detecting matrix of active functionally integrated bipolar structures and peripheral electronic circuitry for signal amplification and processing. This paper presents experimental results of α-particles and electrons detection with position accuracy and operation speed better than 12.5 μm and 1 ns, respectively. The given estimations show the capabilities of this detector and its advantages in comparison with analogs.

  5. Theory of diffusion of active particles that move at constant speed in two dimensions

    Science.gov (United States)

    Sevilla, Francisco J.; Gómez Nava, Luis A.

    2014-08-01

    Starting from a Langevin description of active particles that move with constant speed in infinite two-dimensional space and its corresponding Fokker-Planck equation, we develop a systematic method that allows us to obtain the coarse-grained probability density of finding a particle at a given location and at a given time in arbitrary short-time regimes. By going beyond the diffusive limit, we derive a generalization of the telegrapher equation. Such generalization preserves the hyperbolic structure of the equation and incorporates memory effects in the diffusive term. While no difference is observed for the mean-square displacement computed from the two-dimensional telegrapher equation and from our generalization, the kurtosis results in a sensible parameter that discriminates between both approximations. We carry out a comparative analysis in Fourier space that sheds light on why the standard telegrapher equation is not an appropriate model to describe the propagation of particles with constant speed in dispersive media.

  6. Tight coupling of particle size, number and composition in atmospheric cloud droplet activation

    Directory of Open Access Journals (Sweden)

    D. O. Topping

    2012-04-01

    Full Text Available The substantial uncertainty in the indirect effect of aerosol particles on radiative forcing in large part arises from the influences of atmospheric aerosol particles on (i the brightness of clouds, exerting significant shortwave cooling with no appreciable compensation in the long wave, and on (ii their ability to precipitate, with implications for cloud cover and lifetime.

    Predicting the ambient conditions at which aerosol particles may become cloud droplets is largely reliant on an equilibrium relationship derived by Köhler (1936. However, the theoretical basis of the relationship restricts its application to particles solely comprising involatile compounds and water, whereas a substantial fraction of particles in the real atmosphere will contain potentially thousands of semi-volatile organic compounds in addition to containing semi-volatile inorganic components such as ammonium nitrate.

    We show that equilibration of atmospherically reasonable concentrations of organic compounds with a growing particle as the ambient humidity increases has potentially larger implications on cloud droplet formation than any other equilibrium compositional dependence, owing to inextricable linkage between the aerosol composition, a particles size and concentration under ambient conditions.

    Whilst previous attempts to account for co-condensation of gases other than water vapour have been restricted to one inorganic condensate, our method demonstrates that accounting for the co-condensation of any number of organic compounds substantially decreases the saturation ratio of water vapour required for droplet activation. This effect is far greater than any other compositional dependence; more so even than the unphysical effect of surface tension reduction in aqueous organic mixtures, ignoring differences in bulk and surface surfactant concentrations.

  7. Cationic Biomimetic Particles of Polystyrene/Cationic Bilayer/Gramicidin for Optimal Bactericidal Activity

    Directory of Open Access Journals (Sweden)

    Gabriel R. S. Xavier

    2017-12-01

    Full Text Available Nanostructured particles of polystyrene sulfate (PSS covered by a cationic lipid bilayer of dioctadecyldimethylammonium bromide (DODAB incorporated gramicidin D (Gr yielding optimal and broadened bactericidal activity against both Escherichia coli and Staphylococcus aureus. The adsorption of DODAB/Gr bilayer onto PSS nanoparticles (NPs increased the zeta-average diameter by 8–10 nm, changed the zeta-potential of the NPs from negative to positive, and yielded a narrow size distributions for the PSS/DODAB/Gr NPs, which displayed broad and maximal microbicidal activity at very small concentrations of the antimicrobials, namely, 0.057 and 0.0057 mM DODAB and Gr, respectively. The results emphasized the advantages of highly-organized, nanostructured, and cationic particles to achieve hybrid combinations of antimicrobials with broad spectrum activity at considerably reduced DODAB and Gr concentrations.

  8. Discontinuous fluidization transition in time-correlated assemblies of actively deforming particles

    Science.gov (United States)

    Tjhung, Elsen; Berthier, Ludovic

    2017-11-01

    Tracking experiments in dense biological tissues reveal a diversity of sources for local energy injection at the cell scale. The effect of cell motility has been largely studied, but much less is known about the effect of the observed volume fluctuations of individual cells. We consider a microscopic model of "actively deforming" particles where local fluctuations of the particle size constitute a unique source of motion. We demonstrate that collective motion can emerge under the sole influence of such active volume fluctuations. We interpret the onset of diffusive motion as a nonequilibrium first-order phase transition, which arises at a well-defined amplitude of self-deformation. This behavior contrasts with the glassy dynamics produced by self-propulsion, but resembles the mechanical response of soft solids under mechanical deformation. It thus constitutes an example of an active yielding transition.

  9. Lipoprotein particle distribution and skeletal muscle lipoprotein lipase activity after acute exercise

    LENUS (Irish Health Repository)

    Harrison, Michael

    2012-06-06

    AbstractBackgroundMany of the metabolic effects of exercise are due to the most recent exercise session. With recent advances in nuclear magnetic resonance spectroscopy (NMRS), it is possible to gain insight about which lipoprotein particles are responsible for mediating exercise effects.MethodsUsing a randomized cross-over design, very low density lipoprotein (VLDL) responses were evaluated in eight men on the morning after i) an inactive control trial (CON), ii) exercising vigorously on the prior evening for 100 min followed by fasting overnight to maintain an energy and carbohydrate deficit (EX-DEF), and iii) after the same exercise session followed by carbohydrate intake to restore muscle glycogen and carbohydrate balance (EX-BAL).ResultsThe intermediate, low and high density lipoprotein particle concentrations did not differ between trials. Fasting triglyceride (TG) determined biochemically, and mean VLDL size were lower in EX-DEF but not in EX-BAL compared to CON, primarily due to a reduction in VLDL-TG in the 70–120 nm (large) particle range. In contrast, VLDL-TG was lower in both EX-DEF and EX-BAL compared to CON in the 43–55 nm (medium) particle range. VLDL-TG in smaller particles (29–43 nm) was unaffected by exercise. Because the majority of VLDL particles were in this smallest size range and resistant to change, total VLDL particle concentration was not different between any of these conditions. Skeletal muscle lipoprotein lipase (LPL) activity was also not different across these 3 trials. However, in CON only, the inter-individual differences in LPL activity were inversely correlated with fasting TG, VLDL-TG, total, large and small VLDL particle concentration and VLDL size, indicating a regulatory role for LPL in the non-exercised state.ConclusionsThese findings reveal a high level of differential regulation between different sized triglyceride-rich lipoproteins following exercise and feeding, in the absence of changes in LPL activity.

  10. Optimal run-and-tumble-based transportation of a Janus particle with active steering.

    Science.gov (United States)

    Mano, Tomoyuki; Delfau, Jean-Baptiste; Iwasawa, Junichiro; Sano, Masaki

    2017-03-28

    Although making artificial micrometric swimmers has been made possible by using various propulsion mechanisms, guiding their motion in the presence of thermal fluctuations still remains a great challenge. Such a task is essential in biological systems, which present a number of intriguing solutions that are robust against noisy environmental conditions as well as variability in individual genetic makeup. Using synthetic Janus particles driven by an electric field, we present a feedback-based particle-guiding method quite analogous to the "run-and-tumbling" behavior of Escherichia coli but with a deterministic steering in the tumbling phase: the particle is set to the run state when its orientation vector aligns with the target, whereas the transition to the "steering" state is triggered when it exceeds a tolerance angle [Formula: see text] The active and deterministic reorientation of the particle is achieved by a characteristic rotational motion that can be switched on and off by modulating the ac frequency of the electric field, which is reported in this work. Relying on numerical simulations and analytical results, we show that this feedback algorithm can be optimized by tuning the tolerance angle [Formula: see text] The optimal resetting angle depends on signal to noise ratio in the steering state, and it is shown in the experiment. The proposed method is simple and robust for targeting, despite variability in self-propelling speeds and angular velocities of individual particles.

  11. Pre-activation of aerosol particles by ice preserved in pores

    Science.gov (United States)

    Marcolli, Claudia

    2017-02-01

    Pre-activation denotes the capability of particles or materials to nucleate ice at lower relative humidities or higher temperatures compared to their intrinsic ice nucleation efficiency after having experienced an ice nucleation event or low temperature before. This review presumes that ice preserved in pores is responsible for pre-activation and analyses pre-activation under this presumption. Idealized trajectories of air parcels are used to discuss the pore characteristics needed for ice to persist in pores and to induce macroscopic ice growth out of the pores. The pore width needed to keep pores filled with water decreases with decreasing relative humidity as described by the inverse Kelvin equation. Thus, narrow pores remain filled with ice well below ice saturation. However, the smaller the pore width, the larger the melting and freezing point depressions within the pores. Therefore, pre-activation due to pore ice is constrained by the melting of ice in narrow pores and the sublimation of ice from wide pores imposing restrictions on the temperature and relative humidity range of pre-activation for cylindrical pores. Ice is better protected in ink-bottle-shaped pores with a narrow opening leading to a large cavity. However, whether pre-activation is efficient also depends on the capability of ice to grow macroscopically, i.e. out of the pore. A strong effect of pre-activation is expected for swelling pores, because at low relative humidity (RH) their openings narrow and protect the ice within them against sublimation. At high relative humidities, they open up and the ice can grow to macroscopic size and form an ice crystal. Similarly, ice protected in pockets is perfectly sheltered against sublimation but needs the dissolution of the surrounding matrix to be effective. Pores partially filled with condensable material may also show pre-activation. In this case, complete filling occurs at lower RH than for empty pores and freezing shifts to lower temperatures.Pre-activation

  12. EHMS: Exhaust Heat Management System

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, T.; Schmidt, M.; Weinbrenner, M.; Geskes, P. [Behr GmbH und Co. KG, Stuttgart (Germany)

    2006-07-01

    Pollutant concentrations in diesel engines are reduced by cooling of the recirculated exhaust. This reduces emissions and particulate matter. The cooler technology can also be used for heating the passenger compartment faster and more economically. The authors present a model ready for seral production, including an exhaust flap for bypass control for use as auxiliary heating system. Further applications in gasoline engines are pointed out. (orig.)

  13. μ-reactor measurements of catalytic activity of mass selected nano-particles

    DEFF Research Database (Denmark)

    Riedel, Jakob Nordheim

    The work of this thesis revolves around catalytic activity measurements of nano-particles tested using a μ-reactor platform, developed and produced at DTU, in a collaboration between CINF and Nanotech. The thesis contains the results from two separate research projects; both utilising μ-reactors ......The work of this thesis revolves around catalytic activity measurements of nano-particles tested using a μ-reactor platform, developed and produced at DTU, in a collaboration between CINF and Nanotech. The thesis contains the results from two separate research projects; both utilising μ......-reactors in combination with surface science techniques and computer simulations. The first project described is a study of hydrogen dissociation on mono-disperse platinum clusters. The second project studies methanation from carbon monoxide and hydrogen on nano-particles of nickel-iron alloys. The second study is a work...... stable. DFT simulations demonstrated that even a single oxygen atom binds strongly to SiO2-supported Pt8 clusters and changes the morphology and chemical properties of the cluster. Catalytic methanation reaction from CO and H2 was studied on Ni75Fe25 nano-particles with sizes 3.5nm, 5nm, 7nm and 9nm...

  14. Ice nucleation active particles in continental air samples over Mainz, Germany

    Science.gov (United States)

    Pummer, Bernhard G.; Pöschl, Ulrich; Fröhlich-Nowoisky, Janine

    2016-04-01

    Aerosol particles are of central importance for atmospheric chemistry and physics, climate and public health. Some of these particles possess ice nucleation activity (INA), which is highly relevant for cloud formation and precipitation. In 2010, air filter samples were collected with a high-volume filter sampler separating fine and coarse particles (aerodynamic cut-off diameter 3 μm) in Mainz, Germany. In this study, the INA of the atmospheric particles deposited on these filters was determined. Therefore,they were extracted with ultrapure water, which was then measured in a droplet freezing assay, as described in Fröhlich-Nowoisky et al. (2015). The determined concentration of ice nucleators (INs) was between 0.3 and 2per m³ at 266 K, and between5 and 75 per m³ at 260 K. The INs were further characterized by different treatments, like heating (308 K, 371 K), filtration (0.1 μm, 300 kDa), and digestion with papain (10 mg/ml). We further investigated, which atmospheric conditions (e.g. weather) and distinguished events (e.g. dust storms, volcanic eruptions, and pollen peaks) influenced the number and nature of these INs. Fröhlich-Nowoisky, J., Hill, T. C. J., Pummer, B. G., Yordanova, P., Franc, G. D., and Pöschl, U.: Ice nucleation activity in the widespread soil fungus Mortierella alpina, Biogeosci., 12, 1057-1071, doi:10.5194/bg-12-1057-2015, 2015.

  15. Electrodeposition, characterization, and antibacterial activity of zinc/silver particle composite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Reyes-Vidal, Y.; Suarez-Rojas, R.; Ruiz, C.; Torres, J. [Center of Research and Technological Development in Electrochemistry (CIDETEQ), Parque Tecnológico Sanfandila, Pedro Escobedo, Querétaro, A.P.064, C.P.76703, Querétaro (Mexico); Ţălu, Ştefan [Technical University of Cluj-Napoca, Faculty of Mechanical Engineering, Department of AET, Discipline of Descriptive Geometry and Engineering Graphics, 103-105 B-dul Muncii St., Cluj-Napoca 400641 Cluj (Romania); Méndez, Alia [Centro de Química-ICUAP Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria Puebla, 72530 Puebla (Mexico); Trejo, G., E-mail: gtrejo@cideteq.mx [Center of Research and Technological Development in Electrochemistry (CIDETEQ), Parque Tecnológico Sanfandila, Pedro Escobedo, Querétaro, A.P.064, C.P.76703, Querétaro (Mexico)

    2015-07-01

    Highlights: • Zn/AgPs composites coatings were formed for electrodeposition. • CTAB promotes occlusion of silver particles in the coating. • Zn/AgPs coatings present very good antibacterial activity. - Abstract: Composite coatings consisting of zinc and silver particles (Zn/AgPs) with antibacterial activity were prepared using an electrodeposition technique. The morphology, composition, and structure of the Zn/AgPs composite coatings were analyzed using scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), inductively coupled plasma (ICP) spectrometry, and X-ray diffraction (XRD). The antibacterial properties of the coatings against the microorganisms Escherichia coli as a model Gram-negative bacterium and Staphylococcus aureus as a model Gram-positive bacterium were studied quantitatively and qualitatively. The results revealed that the dispersant cetyltrimethylammonium bromide (CTAB) assisted in the formation of a stable suspension of Ag particles in the electrolytic bath for 24 h. Likewise, a high concentration of CTAB in the electrolytic bath promoted an increase in the number of Ag particles occluded in the Zn/AgPs coatings. The Zn/AgPs coatings that were obtained were compact, smooth, and shiny materials. Antimicrobial tests performed on the Zn/AgPs coatings revealed that the inhibition of bacterial growth after 30 min of contact time was between 91% and 98% when the AgPs content ranged from 4.3 to 14.0 mg cm{sup −3}.

  16. Influence of adhesion to activated carbon particles on the viability of waterborne pathogenic bacteria under flow.

    Science.gov (United States)

    van der Mei, Henny C; Atema-Smit, Jelly; Jager, Debbie; Langworthy, Don E; Collias, Dimitris I; Mitchell, Michael D; Busscher, Henk J

    2008-07-01

    In rural areas around the world, people often rely on water filtration plants using activated carbon particles for safe water supply. Depending on the carbon surface, adhering microorganisms die or grow to form a biofilm. Assays to assess the efficacy of activated carbons in bacterial removal do not allow direct observation of bacterial adhesion and the determination of viability. Here we propose to use a parallel plate flow chamber with carbon particles attached to the bottom plate to study bacterial adhesion to individual carbon particles and determine the viability of adhering bacteria. Observation and enumeration is done after live/dead staining in a confocal laser scanning microscope. Escherichiae coli adhered in higher numbers than Raoultella terrigena, except to a coconut-based carbon, which showed low bacterial adhesion compared to other wood-based carbon types. After adhesion, 83-96% of the bacteria adhering to an acidic carbon were dead, while on a basic carbon 54-56% were dead. A positively charged, basic carbon yielded 76-78% bacteria dead, while on a negatively charged coconut-based carbon only 32-37% were killed upon adhesion. The possibility to determine both adhesion as well as the viability of adhering bacteria upon adhesion to carbon particles is most relevant, because if bacteria adhere but remain viable, this still puts the water treatment system at risk, as live bacteria can grow and form a biofilm that can then be shedded to cause contamination. (c) 2008 Wiley Periodicals, Inc.

  17. Bioinspired synthesis of polydopamine/Ag nanocomposite particles with antibacterial activities.

    Science.gov (United States)

    Wu, Chengjiao; Zhang, Guoxing; Xia, Tian; Li, Zhenni; Zhao, Kai; Deng, Ziwei; Guo, Dingzong; Peng, Bo

    2015-10-01

    Mussel-inspired chemistry (polydopamine) offers great opportunities to develop inexpensive and efficient process for many types of materials with complex shapes and functions in a mild and friendly environment. This paper describes a facile, yet green approach to synthesize polydopamine/silver (PDA/Ag) nanocomposite particles with a combination use of polydopamine chemistry and electroless metallization of Ag. In this approach, monodisperse spherical polydopamine particles are first synthesized by the oxidation and self-polymerization of dopamine (monomer) in an alkaline water-ethanol solution at room temperature, which are served as the active templates for secondary reactions due to the abundant catechol and amine groups on the surface. Subsequently, the silver precursor-[Ag(NH3)2](+) ions introduced are easily absorbed onto the surface of the PDA particles, and are immediately in situ reduced to metallic Ag nanoparticles with the help of these active catechol and amine groups. During the preparation, no additional reductants, toxic reagents and intricate instruments are needed. These as-synthesized PDA/Ag nanocomposite particles are ideal candidates for antibacterial application because they do not show significant cytotoxicity against HEK293T human embryonic kidney cells in the in vitro cytotoxicity assay, whereas demonstrate enhanced antibacterial abilities against Escherichia coli (Gram-negative bacteria) and Staphylococcus aureus (Gram-positive bacteria) in the antibacterial assays. Owing to their excellent cytocompatibilities and antibacterial activities, these PDA/Ag nanocomposite particles can be considered as the promising antibacterial materials for future biomedical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Understanding the Role of Water in Modifying Particle Mixing States for CCN Activity

    Science.gov (United States)

    Vu, D. N.; Gao, S.; Pierce, J. R.; Asa-Awuku, A. A.

    2014-12-01

    CCN data sets from ambient and chamber studies, which consist of complex heterogeneous mixtures of organic and inorganic aerosol mixtures, may not show a single activation curve but instead can exhibit multiple activations not associated with doubly charged particles. It has been suggested that these activation curves may be representative of multiple externally mixed compounds, whereas single activation curves are representative of single component or multicomponent internally mixed aerosols. To characterize and modify mixing states, a new laminar flow tube apparatus was developed to control the extent of mixing of organic and inorganic fractions under different environmental conditions such as relative humidity. Data sets yielding multiple activation curves have been recreated by mixing multiple inorganic and organic compounds. Preliminary results suggest that aerosol water is a significant factor; under dry conditions, the aerosols remained externally mixed while humid conditions facilitated internal mixing. For example, ammonium sulfate (inorganic) and succinic acid (organic) when dry, maintained an external mixture and multiple activation curves were observed to be constant. Under humid conditions, external mixing was initially observed; however, the aerosol water promoted internal mixing and the activation curves were observed to converge into a single curve. The data agrees well with Köhler Theory and single parameter (kappa) theory thermodynamic predictions of droplet activation. Data sets are also compared with a diffusion based coagulation particle model to predict mixing behavior. The method of analysis and the effect of mixing states of multiple components on the supersaturated hygroscopic properties of aerosols are presented.

  19. Exposure to submicron particles (PM1.0) from diesel exhaust and pollen allergens of human lung epithelial cells induces morphological changes of mitochondria tonifilaments and rough endoplasmic reticulum.

    Science.gov (United States)

    Mazzarella, Gennaro; Lucariello, Angela; Bianco, Andrea; Calabrese, Cecilia; Thanassoulas, Theodoros; Savarese, Leonilde; Fiumarella, Angelamaria; Esposito, Vincenzo; DE Luca, Antonio

    2014-01-01

    In recent literature, little has been said regarding the morphological changes that occur in lung cells after treatment with particles and nanoparticles. Using an in vitro model of type-II lung epithelium (A549), we studied the effects of submicron particles (PM1.0), Parietaria officinalis (ALL), and PM1.0 + ALL together. To date several biochemical effects have been described, instead few data exist in literature regarding morphological events following these treatments, in particular we focused on the morphological changes and distribution of mitochondria, tonifilaments and rough endoplasmic reticulum, using a transmission electron microscopic (TEM) approach. After exposure to PM1.0 particles (PM1.0), Parietaria officinalis as allergen, and PM1.0 with P. officinalis, changes in the cytoplasmic area were observed, such as damage to mitochondria and morphological alterations of the tonifilaments and rough endoplasmic reticulum. The data obtained strongly support the hypothesis that cells in contact with submicron particles (PM1.0), or P. officinalis, undergo alteration of their metabolism. Copyright © 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  20. Catalytic activity in individual cracking catalyst particles imaged throughout different life stages by selective staining.

    Science.gov (United States)

    Buurmans, Inge L C; Ruiz-Martínez, Javier; Knowles, William V; van der Beek, David; Bergwerff, Jaap A; Vogt, Eelco T C; Weckhuysen, Bert M

    2011-09-18

    Fluid catalytic cracking (FCC) is the major conversion process used in oil refineries to produce valuable hydrocarbons from crude oil fractions. Because the demand for oil-based products is ever increasing, research has been ongoing to improve the performance of FCC catalyst particles, which are complex mixtures of zeolite and binder materials. Unfortunately, there is limited insight into the distribution and activity of individual zeolitic domains at different life stages. Here we introduce a staining method to visualize the structure of zeolite particulates and other FCC components. Brønsted acidity maps have been constructed at the single particle level from fluorescence microscopy images. By applying a statistical methodology to a series of catalysts deactivated via industrial protocols, a correlation is established between Brønsted acidity and cracking activity. The generally applicable method has clear potential for catalyst diagnostics, as it determines intra- and interparticle Brønsted acidity distributions for industrial FCC materials.

  1. Catalytic activity in individual cracking catalyst particles imaged throughout different life stages by selective staining

    Science.gov (United States)

    Buurmans, Inge L. C.; Ruiz-Martínez, Javier; Knowles, William V.; van der Beek, David; Bergwerff, Jaap A.; Vogt, Eelco T. C.; Weckhuysen, Bert M.

    2011-11-01

    Fluid catalytic cracking (FCC) is the major conversion process used in oil refineries to produce valuable hydrocarbons from crude oil fractions. Because the demand for oil-based products is ever increasing, research has been ongoing to improve the performance of FCC catalyst particles, which are complex mixtures of zeolite and binder materials. Unfortunately, there is limited insight into the distribution and activity of individual zeolitic domains at different life stages. Here we introduce a staining method to visualize the structure of zeolite particulates and other FCC components. Brønsted acidity maps have been constructed at the single particle level from fluorescence microscopy images. By applying a statistical methodology to a series of catalysts deactivated via industrial protocols, a correlation is established between Brønsted acidity and cracking activity. The generally applicable method has clear potential for catalyst diagnostics, as it determines intra- and interparticle Brønsted acidity distributions for industrial FCC materials.

  2. SEMI-ACTIVE DAMPING PERFORMANCE OF IRON PARTICLE FILLED SILICONE RUBBER

    Directory of Open Access Journals (Sweden)

    Florian Dirisamer

    2016-02-01

    Full Text Available The aim of this work was to design, produce and evaluate a demonstrator to visualize the magneto-induced damping behaviour of materials. In contrast to standard materials, the damping coefficient of iron particle filled silicone rubbers can be controlled by a semi-active magnetic field. This field effect should be characterized in order to evaluate the suitability of these magnetorheological silicone elastomers for the use in different configurations and applications.

  3. Particle size, shape and activity for photocatalysis on titania anatase nanoparticles in aqueous surroundings.

    Science.gov (United States)

    Li, Ye-Fei; Liu, Zhi-Pan

    2011-10-05

    TiO(2) nanoparticles have been widely utilized in photocatalysis, but the atomic level understanding on their working mechanism falls much short of expectations. In particular, the correlation between the particle structure and the photocatalytic activity is not established yet, although it was observed that the activity is sensitive to the particle size and shape. This work, by investigating a series of TiO(2) anatase nanoparticles with different size and shape as the photocatalyst for water oxidation, correlates quantitatively the particle size and shape with the photocatalytic activity of the oxygen evolution reaction (OER). Extensive density functional theory (DFT) calculations combined with the periodic continuum solvation model have been utilized to compute the electronic structure of nanoparticles in aqueous solution and provide the reaction energetics for the key elementary reaction. We demonstrate that the equilibrium shape of nanoparticle is sensitive to its size from 1 to 30 nm, and the sharp crystals possess much higher activity than the flat crystals in OER, which in combination lead to the morphology dependence of photocatalytic activity. The conventionally regarded quantum size effect is excluded as the major cause. The physical origin for the shape-activity relationship is identified to be the unique spatial separation/localization of the frontier orbitals in the sharp nanoparticles, which benefits the adsorption of the key reaction intermediate (i.e., OH) in OER on the exposed five-coordinated Ti of {101} facet. The theoretical results here provide a firm basis for maximizing photocatalytic activity via nanostructure engineering and are also of significance for understanding photocatalysis on nanomaterials in general.

  4. 46 CFR 169.609 - Exhaust systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Exhaust systems. 169.609 Section 169.609 Shipping COAST... Electrical Internal Combustion Engine Installations § 169.609 Exhaust systems. Engine exhaust installations... Yacht Council, Inc. Standard P-1, “Safe Installation of Exhaust Systems for Propulsion and Auxiliary...

  5. 49 CFR 325.91 - Exhaust systems.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Exhaust systems. 325.91 Section 325.91... EMISSION STANDARDS Exhaust Systems and Tires § 325.91 Exhaust systems. Link to an amendment published at 75 FR 57193, Sept. 20, 2010. A motor vehicle does not conform to the visual exhaust system inspection...

  6. Melatonin attenuates titanium particle-induced osteolysis via activation of Wnt/β-catenin signaling pathway.

    Science.gov (United States)

    Ping, Zichuan; Hu, Xuanyang; Wang, Liangliang; Shi, Jiawei; Tao, Yunxia; Wu, Xiexing; Hou, Zhenyang; Guo, Xiaobin; Zhang, Wen; Yang, Huilin; Xu, Yaozeng; Wang, Zhirong; Geng, Dechun

    2017-03-15

    Wear debris-induced inhibition of bone regeneration and extensive bone resorption were common features in peri-prosthetic osteolysis (PPO). Here, we investigated the effect of melatonin on titanium particle-stimulated osteolysis in a murine calvariae model and mouse-mesenchymal-stem cells (mMSCs) culture system. Melatonin inhibited titanium particle-induced osteolysis and increased bone formation at osteolytic sites, confirmed by radiological and histomorphometric data. Furthermore, osteoclast numbers decreased dramatically in the low- and high-melatonin administration mice, as respectively, compared with the untreated animals. Melatonin alleviated titanium particle-induced depression of osteoblastic differentiation and mineralization in mMSCs. Mechanistically, melatonin was found to reduce the degradation of β-catenin, levels of which were decreased in presence of titanium particles both in vivo and in vitro. To further ensure whether the protective effect of melatonin was mediated by the Wnt/β-catenin signaling pathway, ICG-001, a selective β-catenin inhibitor, was added to the melatonin-treated groups and was found to attenuate the effect of melatonin on mMSC mineralization. We also demonstrated that melatonin modulated the balance between receptor activator of nuclear factor kappa-B ligand and osteoprotegerin via activation of Wnt/β-catenin signaling pathway. These findings strongly suggest that melatonin represents a promising candidate in the treatment of PPO. Peri-prosthetic osteolysis, initiated by wear debris-induced inhibition of bone regeneration and extensive bone resorption, is the leading cause for implant failure and reason for revision surgery. In the current study, we demonstrated for the first time that melatonin can induce bone regeneration and reduce bone resorption at osteolytic sites caused by titanium-particle stimulation. These effects might be mediated by activating Wnt/β-catenin signaling pathway and enhancing osteogenic

  7. Particle shape dependence of CD8+ T cell activation by artificial antigen presenting cells.

    Science.gov (United States)

    Sunshine, Joel C; Perica, Karlo; Schneck, Jonathan P; Green, Jordan J

    2014-01-01

    Previous work developing particle-based acellular, artificial antigen presenting cells (aAPCs) has focused exclusively on spherical platforms. To explore the role of shape, we generated ellipsoidal PLGA microparticles with varying aspect ratios (ARs) and synthesized aAPCs from them. The ellipsoidal biomimetic aAPCs with high-AR showed significantly enhanced in vitro and in vivo activity above spherical aAPCs with particle volume and antigen content held constant. Confocal imaging indicates that CD8+ T cells preferentially migrate to and are activated by interaction with the long axis of the aAPC. Importantly, enhanced activity of high-AR aAPCs was seen in a mouse melanoma model, with high-AR aAPCs improving melanoma survival compared to non-cognate aAPCs (p = 0.004) and cognate spherical aAPCs (p = 0.05). These findings indicate that particle geometry is a critical design criterion in the generation of aAPCs, and may offer insight into the essential role of geometry in the interaction between CD8+ T cells and biological APCs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Single Atomic Iron Catalysts for Oxygen Reduction in Acidic Media: Particle Size Control and Thermal Activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanguang [Department; Hwang, Sooyeon [Center; Wang, Maoyu [School; Feng, Zhenxing [School; Karakalos, Stavros [Department; Luo, Langli [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Qiao, Zhi [Department; Xie, Xiaohong [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Wang, Chongmin [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Su, Dong [Center; Shao, Yuyan [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Wu, Gang [Department

    2017-09-26

    To significantly reduce the cost of proton exchange membrane (PEM) fuel cells, current Pt must be replaced by platinum-metal-group (PGM)-free catalysts for the oxygen reduction reaction (ORR) in acid. We report here a new class of high-performance atomic iron dispersed carbon catalysts through controlled chemical doping of iron ions into zinc-zeolitic imidazolate framework (ZIF), a type of metal-organic framework (MOF). The novel synthetic chemistry enables accurate size control of Fe-doped ZIF catalyst particles with a wide range from 20 to 1000 nm without changing chemical properties, which provides a great opportunity to increase the density of active sites that is determined by the particle size. We elucidated the active site formation mechanism by correlating the chemical and structural changes with thermal activation process for the conversion from Fe-N4 complex containing hydrocarbon networks in ZIF to highly active FeNx sites embedded into carbon. A temperature of 800oC was identified as the critical point to start forming pyridinic nitrogen doping at the edge of the graphitized carbon planes. Further increasing heating temperature to 1100oC leads to increase of graphitic nitrogen, generating possible synergistic effect with FeNx sites to promote ORR activity. The best performing catalyst, which has well-defined particle size around 50 nm and abundance of atomic FeNx sites embedded into carbon structures, achieve a new performance milestone for the ORR in acid including a half-wave potential of 0.85 V vs RHE and only 20 mV loss after 10,000 cycles in O2 saturated H2SO4 electrolyte. The new class PGM-free catalyst with approaching activity to Pt holds great promise for future PEM fuel cells.

  9. The Characterization of the Desulfurization Powder in the Semi-Dry DE-SO2 Process of the Sintering Plant Exhaust Gas and its Interaction with the Soil Particles

    Science.gov (United States)

    Kang, Ling-Chen; Lu, Li-jun; Xue, Gai-feng; Hwang, Jiann-Yang

    The desulfurization (de-SO2) powders are a solid waste obtained from the sintering plants of the iron and steel industries. It is mostly landfilled due to its massive quanti ties and complicate compositions. A new utilization was developed in this study as a de-soil reagent for the treatment of tailings in the open-pit mines. In this paper, the de-SO2 powders were collected from a sintering plant using the semi-dry de-SO2 process. The chemical compositions of the de-SO2 powders were analyzed by titrations and the chemical phases were determined with a X-ray diffractometer (XRD). The size distribution was measured by a laser particle size analyzer. The micro-morphology was observed by a scanning electron microscopy (SEM). Furthermore, the interaction between the de-SO2 powder and the soil particle was studied.

  10. Schlieren image velocimetry measurements in a rocket engine exhaust plume

    Science.gov (United States)

    Morales, Rudy; Peguero, Julio; Hargather, Michael

    2017-11-01

    Schlieren image velocimetry (SIV) measures velocity fields by tracking the motion of naturally-occurring turbulent flow features in a compressible flow. Here the technique is applied to measuring the exhaust velocity profile of a liquid rocket engine. The SIV measurements presented include discussion of visibility of structures, image pre-processing for structure visibility, and ability to process resulting images using commercial particle image velocimetry (PIV) codes. The small-scale liquid bipropellant rocket engine operates on nitrous oxide and ethanol as propellants. Predictions of the exhaust velocity are obtained through NASA CEA calculations and simple compressible flow relationships, which are compared against the measured SIV profiles. Analysis of shear layer turbulence along the exhaust plume edge is also presented.

  11. Spatial ordering and abnormal optical activity of DNA liquid-crystalline dispersion particles

    Directory of Open Access Journals (Sweden)

    Semenov S.V.

    2017-01-01

    Full Text Available In our work, we investigate physicochemical and optical properties of double-strand DNA dispersions. The study of these properties is of biological interest, because it allows one to describe the characteristics of certain classes of chromosomes and DNA containing viruses. The package pattern of DNA molecules in the dispersions particles (DP is examined. The consideration of the DNA liquid-crystalline DP optical activity based on the theory of electromagnetic wave absorption by large molecular aggregates has been performed. The investigation is also focused on various effects induced by the interaction between biological active compounds and DNA in the content of liquid-crystalline DP.

  12. Cloud droplet activation of mixed organic-sulfate particles produced by the photooxidation of isoprene

    Directory of Open Access Journals (Sweden)

    S. M. King

    2010-04-01

    Full Text Available The cloud condensation nuclei (CCN properties of ammonium sulfate particles mixed with organic material condensed during the hydroxyl-radical-initiated photooxidation of isoprene (C5H8 were investigated in the continuous-flow Harvard Environmental Chamber. CCN activation curves were measured for organic particle mass concentrations of 0.5 to 10.0 μg m−3, NOx concentrations from under 0.4 ppbv up to 38 ppbv, particle mobility diameters from 70 to 150 nm, and thermodenuder temperatures from 25 to 100 °C. At 25 °C, the observed CCN activation curves were accurately described by a Köhler model having two internally mixed components, namely ammonium sulfate and secondary organic material. The modeled physicochemical parameters of the organic material were equivalent to an effective hygroscopicity parameter κORG of 0.10±0.03, regardless of the C5H8:NOx concentration ratio for the span of >200:0.4 to 50:38 (ppbv:ppbv. The volatilization curves (i.e., plots of the residual organic volume fraction against temperature were also similar for the span of investigated C5H8:NOx ratios, suggesting a broad similarity of particle chemical composition. This suggestion was supported by limited variance at 25 °C among the particle mass spectra. For example, the signal intensity at m/z 44 (which can result from the fragmentation of oxidized molecules believed to affect hygroscopicity and CCN properties varied weakly from 6 to 9% across the range of investigated conditions. In contradistinction to the results for 25 °C, conditioning up to 100 °C in the thermodenuder significantly reduced CCN activity. The altered CCN activity might be explained by chemical reactions (e.g., decomposition or oligomerization of the secondary organic material at elevated temperatures. The study's results at 25 °C, in conjunction with the results of

  13. Motor Vehicle Exhaust Gas Suicide.

    Science.gov (United States)

    Routley, Virginia

    2007-01-01

    In many motorized countries, inhalation of carbon monoxide from motor vehicle exhaust gas (MVEG) has been one of the leading methods of suicide. In some countries it remains so (e.g., Australia 16.0% of suicides in 2005). Relative to other methods it is a planned method and one often used by middle-aged males. The study provides a review of countermeasures aimed at restricting this method of suicide. The prevention measures identified were catalytic converters (introduced to reduce carbon monoxide for environmental reasons); in-cabin sensors; exhaust pipe modification; automatic idling stops; and helpline signage at suicide "hotspots." Catalytic converters are now in 90% of new vehicles worldwide and literature supports them being associated with a reduction in exhaust-gassing suicides. There remain, however, accounts of exhaust-gas fatalities in modern vehicles, whether accidentally or by suicide. These deaths and also crashes from fatigue could potentially be prevented by in-cabin multi-gas sensors, these having been developed to the prototype stage. Helpline signage at an exhaust-gassing suicide "hotspot" had some success in reducing suicides. The evidence on method substitution and whether a reduction in MVEG suicides causes a reduction in total suicides is inconsistent.

  14. Infected dendritic cells are sufficient to mediate the adjuvant activity generated by Venezuelan equine encephalitis virus replicon particles

    OpenAIRE

    Tonkin, Daniel R; Whitmore, Alan; Johnston, Robert E; Barro, Mario

    2012-01-01

    Replicon particles derived from Venezuelan equine encephalitis virus (VEE) are infectious non-propagating particles which act as a safe and potent systemic, mucosal, and cellular adjuvant when delivered with antigen. VEE and VEE replicon particles (VRP) can target multiple cell types including dendritic cells (DCs). The role of these cell types in VRP adjuvant activity has not been previously evaluated, and for these studies we focused on the contribution of DCs to the response to VRP. By ana...

  15. On-chip fluorescence-activated particle counting and sorting system

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Yuejun [Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235 (United States); Wu Xudong [Department of Biomedical Engineering, Chongqing University, Chongqing 400044 (China); Wang, Y.-N. [Department of Mechanical Engineering, National Cheng-Kung University, Tainan 701, Taiwan (China); Li Dongqing [Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235 (United States)], E-mail: dongqing.li@vanderbilt.edu

    2008-09-19

    A fluorescence-activated particle counting and sorting system is developed for lab-on-a-chip applications. This system integrates the microfluidic chip, fluorescence excitation and detection, electronic power switch control, and optical visualization. The automatic sorting function is achieved by electrokinetic flow switching, which is triggered by a pre-set fluorescent threshold. A direct current electric pulse is generated to dispense the fluorescent particles to the collection reservoir. A user-friendly software interface is developed for automatic real-time counting, sorting and visualization. The design of the disposable microfluidic chip is simple and easy for integration. This system represents a promising prototype for development of affordable and portable flow cytometric instruments.

  16. Electromechanical stability of electro-active silicone filled with high permittivity particles undergoing large deformation

    Science.gov (United States)

    Liu, Liwu; Liu, Yanju; Zhang, Zhen; Li, Bo; Leng, Jinsong

    2010-11-01

    In this paper, an expression for the permittivity of electro-active silicone undergoing large deformation with high permittivity particles filled uniformly has been proposed. Two expressions are proposed for the permittivity, one based on experimental tests and the other based on the theory of composite material. By applying the thermodynamic model incorporating linear dielectric permittivity and nonlinear hyperelastic performance, the mechanical performance and electromechanical stability of the coupling system constituted by silicone filled with PMN-PT have been studied. The results show that the critical electric field decreases, namely the stability performance of the system declines when the content of PMN-PT c(v) increases and the electrostrictive coefficients increase. The results are beneficial for us to understand deeply the influence of the filled particle on the stability performance of silicone and to guide the design and manufacture of actuators and sensors based on dielectric elastomers.

  17. Two-dimensional dynamics of a trapped active Brownian particle in a shear flow.

    Science.gov (United States)

    Li, Yunyun; Marchesoni, Fabio; Debnath, Tanwi; Ghosh, Pulak K

    2017-12-01

    We model the two-dimensional dynamics of a pointlike artificial microswimmer diffusing in a harmonic trap subject to the shear flow of a highly viscous medium. The particle is driven simultaneously by the linear restoring force of the trap, the drag force exerted by the flow, and the torque due to the shear gradient. For a Couette flow, elliptical orbits in the noiseless regime, and the correlation functions between the particle's displacements parallel and orthogonal to the flow are computed analytically. The effects of thermal fluctuations (translational) and self-propulsion fluctuations (angular) are treated separately. Finally, we discuss how to extend our approach to the diffusion of a microswimmer in a Poiseuille flow. These results provide an accurate reference solution to investigate, both numerically and experimentally, hydrodynamics corrections to the diffusion of active matter in confined geometries.

  18. Clausius Relation for Active Particles: What Can We Learn from Fluctuations

    Directory of Open Access Journals (Sweden)

    Andrea Puglisi

    2017-07-01

    Full Text Available Many kinds of active particles, such as bacteria or active colloids, move in a thermostatted fluid by means of self-propulsion. Energy injected by such a non-equilibrium force is eventually dissipated as heat in the thermostat. Since thermal fluctuations are much faster and weaker than self-propulsion forces, they are often neglected, blurring the identification of dissipated heat in theoretical models. For the same reason, some freedom—or arbitrariness—appears when defining entropy production. Recently three different recipes to define heat and entropy production have been proposed for the same model where the role of self-propulsion is played by a Gaussian coloured noise. Here we compare and discuss the relation between such proposals and their physical meaning. One of these proposals takes into account the heat exchanged with a non-equilibrium active bath: such an “active heat” satisfies the original Clausius relation and can be experimentally verified.

  19. Effects of Diesel Exhaust on Cardiovascular Function and Oxidative Stress.

    Science.gov (United States)

    Wilson, Simon J; Miller, Mark R; Newby, David E

    2017-07-14

    Air pollution is a major global health concern with particulate matter (PM) being especially associated with increases in cardiovascular morbidity and mortality. Diesel exhaust emissions are a particularly rich source of the smallest sizes of PM ("fine" and "ultrafine") in urban environments, and it is these particles that are believed to be the most detrimental to cardiovascular health. Recent Advances: Controlled exposure studies to diesel exhaust in animals and man demonstrate alterations in blood pressure, heart rate, vascular tone, endothelial function, myocardial perfusion, thrombosis, atherogenesis, and plaque stability. Oxidative stress has emerged as a highly plausible pathobiological mechanism by which inhalation of diesel exhaust PM leads to multiple facets of cardiovascular dysfunction. Diesel exhaust inhalation promotes oxidative stress in several biological compartments that can be directly associated with adverse cardiovascular effects. Further studies with more sensitive and specific in vivo human markers of oxidative stress are required to determine if targeting oxidative stress pathways involved in the actions of diesel exhaust PM could be of therapeutic value. Antioxid. Redox Signal. 00, 000-000.

  20. Development of new polysilsesquioxane spherical particles as stabilized active ingredients for sunscreens

    Science.gov (United States)

    Tolbert, Stephanie Helene

    Healthy skin is a sign of positive self-worth, attractiveness and vitality. Compromises to this are frequently caused by extended periods of recreation in the sun and in turn exposure to the harmful effects of UV radiation. To maintain strength and integrity, protection of the skin is paramount. This can be achieved by implementing skin-care products which contain sunscreen active ingredients that provide UV protection. Unfortunately, photo-degradation, toxicity, and photo-allergies limit the effectiveness of present day sunscreen ingredients. Currently, this is moderated by physically embedding within inert silica particles, but leaching of the active ingredient can occur, thereby negating protective efforts. Alternatively, this research details the preparation and investigation of bridged silsesquioxane analogues of commercial ingredients which can be chemically grafted to the silica matrix. Studies with bridged salicylate particles detail facile preparation, minimized leaching, and enhanced UV stability over physically encapsulated and pendant salicylate counterparts. In terms of UVB protective ability, the highest maintenance of sun protection factor (SPF) after extended UV exposure was achieved with bridged incorporation, and has been attributed to corollary UV stability. Additionally, bridged salicylate particles can be classified as broad-spectrum, and rate from moderate to good in terms of UVA protective ability. Particles incorporated with a bridged curcuminoid silsesquioxane were also prepared and displayed comparable results. As such, an attractive method for sunscreen isolation and stabilization has been developed to eliminate the problems associated with current sunscreens, all while maintaining the established UV absorbance profiles of the parent compound. To appreciate the technology utilized in this research, a thorough understanding of sol-gel science as it pertains to hybrid organic/silica particles, including methods of organic fragment

  1. Active coated nano-particle excited by an arbitrarily located electric Hertzian dipole — resonance and transparency effects

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Ziolkowski, Richard W.

    2010-01-01

    The present work investigates the optical properties of active coated spherical nano-particles excited by an arbitrarily located electric Hertzian dipole. The nano-particles are made of specific dielectric and plasmonic materials. The spatial near-field distribution as well as the normalized...... radiation resistance is examined. Both enhanced as well as reduced radiation effects are demonstrated. In particular, it is shown that specific active coated nano-particles can be designed to be resonant, leading to much larger values of the normalized radiation resistance than is the case...... with the corresponding passive coated nano-particles, thereby overcoming the intrinsic losses present in the plasmonic materials. Moreover, it is shown that other active coated nano-particle designs can significantly reduce the normalized radiation resistance; thus both the resonant as well as non...

  2. Measurement of alkali in PFBC exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.H.D.; Swift, W.M.

    1992-11-01

    This project supports the DOE/METC Fossil Energy Program for the development of PFBC technology. Based on the analytical activated-bauxite sorber-bed technique, we are developing the RABSAM as an altemative to the on-line alkali analyzer for field application. As shown in Fig. 1, the RABSAM is a sampling probe containing a regenerable activated-bauxite adsorbent (RABA). It can be inserted directly into the PFBC exhaust duct and requires no HTHP sampling line. Alkali vapors are captured by the adsorbent purely through physical adsorption. The adsorbent is regenerated by a simple water-leaching process, which also recovers the adsorbed alkalis. The alkali analysis of the leachate by atomic absorption (AA) provides a basis for calculating the time-averaged alkali-vapor concentration in the PFBC exhaust. If the RABA is to use commercial grade activated bauxite, the clay impurities in activated bauxite can react with alkali vapors and, therefore, need to be either removed or deactivated. In earlier work, a 6M-LiCl-solution impregnation technique was shown to deactivate these impurities in fresh activated bauxite [8]. During this year, RABA prepared by this technique was tested in a pressurized alkali-vapor sorption test unit to determine its NaCl-vapor capture efficiency and the regenerability of the sorbent by water extraction. Results of this study are presented and discussed.

  3. Measurement of alkali in PFBC exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.H.D.; Swift, W.M.

    1992-01-01

    This project supports the DOE/METC Fossil Energy Program for the development of PFBC technology. Based on the analytical activated-bauxite sorber-bed technique, we are developing the RABSAM as an altemative to the on-line alkali analyzer for field application. As shown in Fig. 1, the RABSAM is a sampling probe containing a regenerable activated-bauxite adsorbent (RABA). It can be inserted directly into the PFBC exhaust duct and requires no HTHP sampling line. Alkali vapors are captured by the adsorbent purely through physical adsorption. The adsorbent is regenerated by a simple water-leaching process, which also recovers the adsorbed alkalis. The alkali analysis of the leachate by atomic absorption (AA) provides a basis for calculating the time-averaged alkali-vapor concentration in the PFBC exhaust. If the RABA is to use commercial grade activated bauxite, the clay impurities in activated bauxite can react with alkali vapors and, therefore, need to be either removed or deactivated. In earlier work, a 6M-LiCl-solution impregnation technique was shown to deactivate these impurities in fresh activated bauxite [8]. During this year, RABA prepared by this technique was tested in a pressurized alkali-vapor sorption test unit to determine its NaCl-vapor capture efficiency and the regenerability of the sorbent by water extraction. Results of this study are presented and discussed.

  4. Semiconductor industry wafer fab exhaust management

    CERN Document Server

    Sherer, Michael J

    2005-01-01

    Given the myriad exhaust compounds and the corresponding problems that they can pose in an exhaust management system, the proper choice of such systems is a complex task. Presenting the fundamentals, technical details, and general solutions to real-world problems, Semiconductor Industry: Wafer Fab Exhaust Management offers practical guidance on selecting an appropriate system for a given application. Using examples that provide a clear understanding of the concepts discussed, Sherer covers facility layout, support facilities operations, and semiconductor process equipment, followed by exhaust types and challenges. He reviews exhaust point-of-use devices and exhaust line requirements needed between process equipment and the centralized exhaust system. The book includes information on wet scrubbers for a centralized acid exhaust system and a centralized ammonia exhaust system and on centralized equipment to control volatile organic compounds. It concludes with a chapter devoted to emergency releases and a separ...

  5. Ultrafine Condensation Particle Counter Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Kuang, C. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-02-01

    The Model 3776 Ultrafine Condensation Particle Counter (UCPC; pictured in Appendix A) is designed for researchers interested in airborne particles smaller than 20 nm. With sensitivity to particles down to 2.5 nm in diameter, this UCPC is ideally suited for atmospheric and climate research, particle formation and growth studies, combustion and engine exhaust research, and nanotechnology research.

  6. Action-projection in Japanese conversation: Topic particles wa, mo and tte for triggering categorization activities

    Directory of Open Access Journals (Sweden)

    Hiroko eTanaka

    2015-08-01

    Full Text Available Conversation analytic work has revealed how anticipatory completions and preemptive actions can offer invaluable glimpses into the cognitive, contextual, grammatical and temporal bases of projectability in turn-taking, by virtue of their potential not only as a display of participants’ online prediction of roughly what it might take to complete a turn-in-progress but also to plan the next move. While the predicate-final word order and the incremental transformability of turns in Japanese generally lead to delayed projectability of turn-endings, this may be partially offset by the capacity of certain postpositional particles to trigger and propel prospective action trajectories. This article engages in a case study of the topic particle wa (and related particles mo and tte, by demonstrating how its grammatical affordances, the categorization activities and cognitive processing it can set in motion, coupled with the immediate contextual and temporal-productional features may coalesce to a point of critical mass, thereby enhancing the projectability of the not-yet-produced trajectory of the current turn. The discussion attempts to contribute to recent debates on ways language-specific lexicogrammatical resources are deeply interlinked with the types of opportunities that are provided for social action.

  7. Molecular and structural properties of polymer composites filled with activated charcoal particles

    Energy Technology Data Exchange (ETDEWEB)

    Tahir, Dahlang, E-mail: dtahir@fmipa.unhas.ac.id; Bakri, Fahrul [Department of Physics, Hasanuddin University, Makassar 90245 Indonesia (Indonesia); Liong, Syarifuddin [Department of Chemistry, Hasanuddin University, Makassar 90245 Indonesia (Indonesia)

    2016-03-11

    We have studied the molecular properties, structural properties, and chemical composition of composites by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy, and X-ray fluorescence (XRF) spectroscopy, respectively. FTIR spectra shows absorption band of hydroxyl group (-OH), methyl group (-CH{sub 3}) and aromatic group (C-C). The absorption band for aromatic group (C-C) shows the formation of carbonaceous in composites. XRF shows chemical composition of composites, which the main chemicals are SO{sub 3}, Cl, and ZnO. The loss on ignition value (LOI) of activated charcoal indicates high carbonaceous matter. The crystallite size for diffraction pattern from hydrogel polymer is about 17 nm and for activated charcoal are about 19 nm. The crystallite size of the polymer is lower than that of activated charcoal, which make possible of the particle from filler in contact with each other to form continuous conducting polymer through polymer matrix.

  8. Sequestration of nanoparticles by an EPS matrix reduces the particle-specific bactericidal activity.

    Science.gov (United States)

    Wang, Qian; Kang, Fuxing; Gao, Yanzheng; Mao, Xuewei; Hu, Xiaojie

    2016-02-09

    Most artificial nanomaterials are known to exhibit broad-spectrum bactericidal activity; however, the defence mechanisms that bacteria use based on extracellular polymeric substances (EPS) to detoxify nanoparticles (NPs) are not well known. We ruled out the possibility of ion-specific bactericidal activity by showing the lack of equivalent dissolved zinc and silicon toxicity and determined the particle-specific toxicity of ZnO and SiO2 nanoparticles (ZnONPs/SiO2NPs) through dialysis isolation experiments. Surprisingly, the manipulation of the E. coli EPS (i.e., no EPS manipulation or EPS removal by sonication/centrifugation) showed that their particle-specific bactericidal activity could be antagonized by NP-EPS sequestration. The survival rates of pristine E. coli (no EPS manipulation) reached 65% (ZnONPs, 500 mg L(-1)) and 79% (SiO2NPs, 500 mg L(-1)), whereas survival rates following EPS removal by sonication/centrifugation were 11% and 63%, respectively. Transmission electron microscopy (TEM) combined with fluorescence micro-titration analysis and Fourier-transform infrared spectroscopy (FTIR) showed that protein-like substances (N-H and C-N in amide II) and secondary carbonyl groups (C=O) in the carboxylic acids of EPS acted as important binding sites that were involved in NP sequestration. Accordingly, the amount and composition of EPS produced by bacteria have important implications for the bactericidal efficacy and potential environmental effects of NPs.

  9. Ultrafine particles from diesel engines induce vascular oxidative stress via JNK activation.

    Science.gov (United States)

    Li, Rongsong; Ning, Zhi; Cui, Jeffery; Khalsa, Bhavraj; Ai, Lisong; Takabe, Wakako; Beebe, Tyler; Majumdar, Rohit; Sioutas, Constantinos; Hsiai, Tzung

    2009-03-15

    Exposure to particulate air pollution is linked to increased incidences of cardiovascular diseases. Ambient ultrafine particles (UFP) from diesel vehicle engines have been shown to be proatherogenic in ApoE knockout mice and may constitute a major cardiovascular risk in humans. We posited that circulating nano-sized particles from traffic pollution sources induce vascular oxidative stress via JNK activation in endothelial cells. Diesel UFP were collected from a 1998 Kenworth truck. Intracellular superoxide assay revealed that these UFP dose-dependently induced superoxide (O(2)(-)) production in human aortic endothelial cells (HAEC). Flow cytometry showed that UFP increased MitoSOX red intensity specific for mitochondrial superoxide. Protein carbonyl content was increased by UFP as an indication of vascular oxidative stress. UFP also up-regulated heme oxygenase-1 (HO-1) and tissue factor (TF) mRNA expression, and pretreatment with the antioxidant N-acetylcysteine significantly decreased their expression. Furthermore, UFP transiently activated JNK in HAEC. Treatment with the JNK inhibitor SP600125 and silencing of both JNK1 and JNK2 with siRNA inhibited UFP-stimulated O(2)(-) production and mRNA expression of HO-1 and TF. Our findings suggest that JNK activation plays an important role in UFP-induced oxidative stress and stress response gene expression.

  10. Sequestration of nanoparticles by an EPS matrix reduces the particle-specific bactericidal activity

    Science.gov (United States)

    Wang, Qian; Kang, Fuxing; Gao, Yanzheng; Mao, Xuewei; Hu, Xiaojie

    2016-02-01

    Most artificial nanomaterials are known to exhibit broad-spectrum bactericidal activity; however, the defence mechanisms that bacteria use based on extracellular polymeric substances (EPS) to detoxify nanoparticles (NPs) are not well known. We ruled out the possibility of ion-specific bactericidal activity by showing the lack of equivalent dissolved zinc and silicon toxicity and determined the particle-specific toxicity of ZnO and SiO2 nanoparticles (ZnONPs/SiO2NPs) through dialysis isolation experiments. Surprisingly, the manipulation of the E. coli EPS (i.e., no EPS manipulation or EPS removal by sonication/centrifugation) showed that their particle-specific bactericidal activity could be antagonized by NP-EPS sequestration. The survival rates of pristine E. coli (no EPS manipulation) reached 65% (ZnONPs, 500 mg L-1) and 79% (SiO2NPs, 500 mg L-1), whereas survival rates following EPS removal by sonication/centrifugation were 11% and 63%, respectively. Transmission electron microscopy (TEM) combined with fluorescence micro-titration analysis and Fourier-transform infrared spectroscopy (FTIR) showed that protein-like substances (N-H and C-N in amide II) and secondary carbonyl groups (C=O) in the carboxylic acids of EPS acted as important binding sites that were involved in NP sequestration. Accordingly, the amount and composition of EPS produced by bacteria have important implications for the bactericidal efficacy and potential environmental effects of NPs.

  11. Exhaust Gas Scrubber Washwater Effluent

    Science.gov (United States)

    2011-11-01

    10 Sulfur Content of Certain Liquid Fuels Exhaust Gas Scrubber Washwater Effluent...diesel and gasoline components DIN Dissolved inorganic nitrogen THC Total hydrocarbon TKN Total Kjeldahl nitrogen HEM Hexane extractable...Benefit Analysis to support the impact assessment accompanying the revision of Directive 1999/32/EC on the sulfur content of certain liquid fuels

  12. Ship exhaust gas plume cooling

    NARCIS (Netherlands)

    Schleijpen, H.M.A.; Neele, P.P.

    2004-01-01

    The exhaust gas plume is an important and sometimes dominating contributor to the infrared signature of ships. Suppression of the infrared ship signatures has been studied by TNO for the Royal Netherlands Navy over considerable time. This study deals with the suppression effects, which can be

  13. First Results from Cherwell, a Monolithic Active Pixel Sensor for Particle Physics

    CERN Document Server

    Nooney, Tamsin; Borri, Marcello; Crooks, Jamie; Headspith, Jon; Inguglia, Gianluca; Kolya, Scott; Lazarus, Ian; Lemmon, Roy; Mylroie-Smith, James; Turchetta, Renato; Velthuis, Jaap; Wilson, Fergus

    2014-01-01

    Cherwell is a CMOS Monolithic Active Pixel Sensor (MAPS) developed for digital calorimetry and charged particle tracking applications. Here, we outline the initial tests carried out to charac- terise the performance of Cherwell, give details of the test beam carried out at CERN and include the first results from this analysis. Three variations of the chip were tested; Type A, a high re- sistivity, low noise sensor, Type B, a standard resisivity, low noise sensor and Type C, a standard resistivity, standard noise sensor. The sensors yield an average RMS noise value per pixel of 9.6 e

  14. Some design characteristics of the AMPTE turn and orbit change maneuvers. [Active Magnetospheric Particle Tracer Explorers

    Science.gov (United States)

    Kechichian, J. A.; Kwong, D. D.

    1985-01-01

    The maneuvers carried out by the Active Magnetospheric Particle Tracer Explorers (AMPTE) including the Charge Composition Explorer (CCE) and the Ion Release Module (IRM) spacecraft are analyzed. Analytic and graphical methods are developed in order to carry out sensitivity analyses that helped design the nominal maneuvers, by taking into account errors in burn initiating time, motor performance, and spin axis pointing. A tradeoff analysis between errors in timing and Delta V magnitude is shown for the IRM orbit transfer, and a technique that allows for the determination of the attitude of spinner spacecraft by way of the observed Doppler shift resulting from an unbalanced turn is investigated.

  15. Detection of alpha particle contamination on ultra low activity-grade integrated circuits

    Directory of Open Access Journals (Sweden)

    Fernandes Ana C.

    2016-01-01

    Full Text Available We propose to apply the superheated droplet detector (SDD technology to the measurement of alpha-particle emissivity on integrated circuits of ultra-low activity grade (< 1α/khcm2 for high reliability applications. This work is based on the SDDs employed within our team to the direct search for dark matter. We describe the modifications in the dark matter SDDs with respect to fabrication, signal analysis and characterization, in order to obtain a device with the adequate detection sensitivity and background noise.

  16. ATR Prohibits Replication Catastrophe by Preventing Global Exhaustion of RPA

    DEFF Research Database (Denmark)

    Toledo Lazaro, Luis Ignacio; Altmeyer, Matthias; Rask, Maj-Britt

    2013-01-01

    origin firing generates an excess of single-stranded DNA that exhausts the nuclear pool of RPA. Partial reduction of RPA accelerated fork breakage, and forced elevation of RPA was sufficient to delay such "replication catastrophe" even in the absence of ATR activity. Conversely, unscheduled origin firing...... induced breakage of stalled forks even in cells with active ATR. Thus, ATR-mediated suppression of dormant origins shields active forks against irreversible breakage via preventing exhaustion of nuclear RPA. This study elucidates how replicating genomes avoid destabilizing DNA damage. Because cancer cells...

  17. A Cinnamon-Derived Procyanidin Compound Displays Anti-HIV-1 Activity by Blocking Heparan Sulfate- and Co-Receptor- Binding Sites on gp120 and Reverses T Cell Exhaustion via Impeding Tim-3 and PD-1 Upregulation.

    Directory of Open Access Journals (Sweden)

    Bridgette Janine Connell

    Full Text Available Amongst the many strategies aiming at inhibiting HIV-1 infection, blocking viral entry has been recently recognized as a very promising approach. Using diverse in vitro models and a broad range of HIV-1 primary patient isolates, we report here that IND02, a type A procyanidin polyphenol extracted from cinnamon, that features trimeric and pentameric forms displays an anti-HIV-1 activity against CXCR4 and CCR5 viruses with 1-7 μM ED50 for the trimer. Competition experiments, using a surface plasmon resonance-based binding assay, revealed that IND02 inhibited envelope binding to CD4 and heparan sulphate (HS as well as to an antibody (mAb 17b directed against the gp120 co-receptor binding site with an IC50 in the low μM range. IND02 has thus the remarkable property of simultaneously blocking gp120 binding to its major host cell surface counterparts. Additionally, the IND02-trimer impeded up-regulation of the inhibitory receptors Tim-3 and PD-1 on CD4+ and CD8+ cells, thereby demonstrating its beneficial effect by limiting T cell exhaustion. Among naturally derived products significantly inhibiting HIV-1, the IND02-trimer is the first component demonstrating an entry inhibition property through binding to the viral envelope glycoprotein. These data suggest that cinnamon, a widely consumed spice, could represent a novel and promising candidate for a cost-effective, natural entry inhibitor for HIV-1 which can also down-modulate T cell exhaustion markers Tim-3 and PD-1.

  18. Gravimetric Measurements of Filtering Facepiece Respirators Challenged With Diesel Exhaust.

    Science.gov (United States)

    Satish, Swathi; Swanson, Jacob J; Xiao, Kai; Viner, Andrew S; Kittelson, David B; Pui, David Y H

    2017-07-01

    Elevated concentrations of diesel exhaust have been linked to adverse health effects. Filtering facepiece respirators (FFRs) are widely used as a form of respiratory protection against diesel particulate matter (DPM) in occupational settings. Previous results (Penconek A, Drążyk P, Moskal A. (2013) Penetration of diesel exhaust particles through commercially available dust half masks. Ann Occup Hyg; 57: 360-73.) have suggested that common FFRs are less efficient than would be expected for this purpose based on their certification approvals. The objective of this study was to measure the penetration of DPM through NIOSH-certified R95 and P95 electret respirators to verify this result. Gravimetric-based penetration measurements conducted using polytetrafluoroethylene (PTFE) and polypropylene (PP) filters were compared with penetration measurements made with a Scanning Mobility Particle Sizer (SMPS, TSI Inc.), which measures the particle size distribution. Gravimetric measurements using PP filters were variable compared to SMPS measurements and biased high due to adsorption of gas phase organic material. Relatively inert PTFE filters adsorbed less gas phase organic material resulting in measurements that were more accurate. To attempt to correct for artifacts associated with adsorption of gas phase organic material, primary and secondary filters were used in series upstream and downstream of the FFR. Correcting for adsorption by subtracting the secondary mass from the primary mass improved the result for both PTFE and PP filters but this correction is subject to 'equilibrium' conditions that depend on sampling time and the concentration of particles and gas phase hydrocarbons. Overall, the results demonstrate that the use of filters to determine filtration efficiency of FFRs challenged with diesel exhaust produces erroneous results due to the presence of gas phase hydrocarbons in diesel exhaust and the tendency of filters to adsorb organic material. Published by

  19. Higher order mode excitation in eccentric active nano-particles for tailoring of the near-field radiation

    DEFF Research Database (Denmark)

    Thorsen, R. O.; Arslanagic, Samel

    2015-01-01

    We examine the excitation of resonant modes inside eccentrically layered cylindrical active nano-particles. The nano-particle is a three-layer structure comprised of a silica core, a free-space middle layer, and an outer shell of silver. It is shown that a concentric configuration, initially desi...... of the gain constant, is shown to be controlled by the direction of the core displacement. The present eccentric active nano-particles may provide alternative strategies for directive near-field radiation relative to the existing designs....

  20. Single Atomic Iron Catalysts for Oxygen Reduction in Acidic Media: Particle Size Control and Thermal Activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanguang; Hwang, Sooyeon; Wang, Maoyu; Feng, Zhenxing; Karakalos, Stavros; Luo, Langli; Qiao, Zhi; Xie, Xiaohong; Wang, Chongmin; Su, Dong; Shao, Yuyan; Wu, Gang (BNL); (Oregon State U.); (SC); (PNNL); (Buffalo)

    2017-09-26

    It remains a grand challenge to replace platinum group metal (PGM) catalysts with earth-abundant materials for the oxygen reduction reaction (ORR) in acidic media, which is crucial for large-scale deployment of proton exchange membrane fuel cells (PEMFCs). Here, we report a high-performance atomic Fe catalyst derived from chemically Fe-doped zeolitic imidazolate frameworks (ZIFs) by directly bonding Fe ions to imidazolate ligands within 3D frameworks. Although the ZIF was identified as a promising precursor, the new synthetic chemistry enables the creation of well-dispersed atomic Fe sites embedded into porous carbon without the formation of aggregates. The size of catalyst particles is tunable through synthesizing Fe-doped ZIF nanocrystal precursors in a wide range from 20 to 1000 nm followed by one-step thermal activation. Similar to Pt nanoparticles, the unique size control without altering chemical properties afforded by this approach is able to increase the number of PGM-free active sites. The best ORR activity is measured with the catalyst at a size of 50 nm. Further size reduction to 20 nm leads to significant particle agglomeration, thus decreasing the activity. Using the homogeneous atomic Fe model catalysts, we elucidated the active site formation process through correlating measured ORR activity with the change of chemical bonds in precursors during thermal activation up to 1100 °C. The critical temperature to form active sites is 800 °C, which is associated with a new Fe species with a reduced oxidation number (from Fe3+ to Fe2+) likely bonded with pyridinic N (FeN4) embedded into the carbon planes. Further increasing the temperature leads to continuously enhanced activity, linked to the rise of graphitic N and Fe–N species. The new atomic Fe catalyst has achieved respectable ORR activity in challenging acidic media (0.5 M H2SO4), showing a half-wave potential of 0.85 V vs RHE and leaving only a 30 mV gap with Pt/C (60 μgPt/cm2). Enhanced stability

  1. Activation cross sections of longer-lived radionuclides produced in germanium by alpha particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Takács, S., E-mail: stakacs@atomki.hu [Institute for Nuclear Research, Hungarian Academy of Sciences, Atomki, 4026 Debrecen (Hungary); Takács, M.P.; Ditrói, F. [Institute for Nuclear Research, Hungarian Academy of Sciences, Atomki, 4026 Debrecen (Hungary); Aikawa, M. [Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Haba, H.; Komori, Y. [Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan)

    2016-09-15

    The cross sections of alpha particles induced nuclear reactions on natural germanium were investigated by using the standard stacked foil target technique, the activation method and high resolution gamma spectrometry. Targets with thickness of about 1 μm were prepared from natural Ge by vacuum evaporation onto 25 μm thick polyimide (Kapton) backing foils. Stacks were composed of Kapton-Ge-Ge-Kapton sandwich target foils and additional titanium monitor foils with nominal thickness of 11 μm to monitor the beam parameters using the {sup nat}Ti(α,x){sup 51}Cr reaction. The irradiations were done with E{sub α} = 20.7 and E{sub α} = 51.25 MeV, I{sub α} = 50 nA alpha particle beams for about 1 h. Direct or cumulative activation cross sections were determined for production of the {sup 72,73,75}Se, {sup 71,72,74,76,78}As, and {sup 69}Ge radionuclides. The obtained experimental cross sections were compared to the results of theoretical calculations taken from the TENDL data library based on the TALYS computer code. A comparison was made with available experimental data measured earlier. Thick target yields were deduced from the experimental cross sections and compared with the data published before.

  2. Integration of active pharmaceutical ingredient solid form selection and particle engineering into drug product design.

    Science.gov (United States)

    Ticehurst, Martyn David; Marziano, Ivan

    2015-06-01

    This review seeks to offer a broad perspective that encompasses an understanding of the drug product attributes affected by active pharmaceutical ingredient (API) physical properties, their link to solid form selection and the role of particle engineering. While the crucial role of active pharmaceutical ingredient (API) solid form selection is universally acknowledged in the pharmaceutical industry, the value of increasing effort to understanding the link between solid form, API physical properties and drug product formulation and manufacture is now also being recognised. A truly holistic strategy for drug product development should focus on connecting solid form selection, particle engineering and formulation design to both exploit opportunities to access simpler manufacturing operations and prevent failures. Modelling and predictive tools that assist in establishing these links early in product development are discussed. In addition, the potential for differences between the ingoing API physical properties and those in the final product caused by drug product processing is considered. The focus of this review is on oral solid dosage forms and dry powder inhaler products for lung delivery. © 2015 Royal Pharmaceutical Society.

  3. Particle Size-Dependent Antibacterial Activity and Murine Cell Cytotoxicity Induced by Graphene Oxide Nanomaterials

    Directory of Open Access Journals (Sweden)

    Lin Zhao

    2016-01-01

    Full Text Available Recent studies have indicated that graphene and its derivative graphene oxide (GO engage in a wide range of antibacterial activities with limited toxicity to human cells. Here, we systematically evaluate the dependence of GO toxicity on the size of the nanoparticles used in treatments: we compare the cytotoxic effects of graphene quantum dots (GQDs, <15 nm, small GOs (SGOs, 50–200 nm, and large GOs (LGOs, 0.5–3 μm. We synthesize the results of bacterial colony count assays and SEM-based observations of morphological changes to assess the antibacterial properties that these GOs bring into effect against E. coli. We also use Live/Dead assays and morphological analysis to investigate changes to mammalian (Murine macrophage-like Raw 264.7 cells induced by the presence of the various GO particle types. Our results demonstrate that LGOs, SGOs, and GQDs possess antibacterial activities and cause mammalian cell cytotoxicity at descending levels of potency. Placing our observations in the context of previous simulation results, we suggest that both the lateral size and surface area of GO particles contribute to cytotoxic effects. We hope that the size dependence elucidated here provides a useful schematic for tuning GO-cell interactions in biomedical applications.

  4. Antibacterial activity of silver: the role of hydrodynamic particle size at nanoscale.

    Science.gov (United States)

    Khurana, Chandni; Vala, Anjana K; Andhariya, Nidhi; Pandey, O P; Chudasama, Bhupendra

    2014-10-01

    Silver shows the highest antimicrobial activities amongst all metals. It is better than many first line antibiotics. The antimicrobial properties of silver can be tuned by altering its physical and surface properties. Researchers have demonstrated enhancement in the antibacterial properties of silver with decreasing particle size from bulk to nano. In the present article, we study the effect of particle size of silver at nanoscale on their antimicrobial properties. Two samples of silver nanoparticles (SNPs) of same physical size (≈8 nm) but different hydrodynamic size (59 and 83 nm) are prepared by chemical reduction of AgNO3 with oleylamine followed by phase transfer with triblock copolymer Pluronic F-127. Their antimicrobial properties are investigated by microdilution method against clinically important strains of gram positive (S. aureus and B. megaterium) and gram negative (P. vulgaris and S. sonnei) bacteria. Nearly 38-50% enhancement in the antibacterial action of SNPs was observed when their hydrodynamic size was reduced to 59 nm from 83 nm. It has been observed that the antibacterial action of SNPs was governed by their hydrodynamic size and not by their crystallite and physical size. The phenomenological model was also proposed which makes an attempt to explain the microscopic mechanism responsible for the size dependent antibacterial activities of silver. © 2013 Wiley Periodicals, Inc.

  5. Active particle control experiments and critical particle flux discriminating between the wall pumping and fuelling in the compact plasma wall interaction device CPD spherical tokamak

    Science.gov (United States)

    Zushi, H.; Hirooka, Y.; Bhattacharyay, R.; Sakamoto, M.; Nakashima, Y.; Yoshinaga, T.; Higashizono, Y.; Hanada, K.; Nishino, N.; Yoshida, N.; Tokunaga, K.; Kado, S.; Shikama, T.; Kawasaki, S.; Okamoto, K.; Miyazaki, T.; Honma, H.; Sato, K. N.; Nakamura, K.; Idei, H.; Hasegawa, M.; Nakashima, H.; Higashijima, A.

    2009-05-01

    Two approaches associated with wall recycling have been performed in a small spherical tokamak device CPD (compact plasma wall interaction experimental device), that is, (1) demonstration of active particle recycling control, namely, 'active wall pumping' using a rotating poloidal limiter whose surface is continuously gettered by lithium and (2) a basic study of the key parameters which discriminates between 'wall pumping and fuelling'. For the former, active control of 'wall pumping' has been demonstrated during 50 kW RF current drive discharges whose pulse length is typically ~300 ms. Although the rotating limiter is located at the outer board, as soon as the rotating drum is gettered with lithium, hydrogen recycling measured with Hα spectroscopy decreases by about a factor of 3 not only near the limiter but also in the centre stack region. Also, the oxygen impurity level measured with O II spectroscopy is reduced by about a factor of 3. As a consequence of the reduced recycling and impurity level, RF driven current has nearly doubled at the same vertical magnetic field. For the latter, global plasma wall interaction with plasma facing components in the vessel is studied in a simple torus produced by electron cyclotron waves with Ip static gas balance (pressure measurement) without external pumping systems has been performed to investigate the role of particle flux on a transition of 'wall fuelling' to 'wall pumping'. It is found that a critical particle flux exists to discriminate between them. Beyond the critical value, a large fraction (~80%) of pressure drop ('wall pumping') is found, suggesting that almost all injected particles are retained in the wall. Below it, a significant pressure rise ('wall fuelling') is found, which indicates that particles are fuelled from the wall during/just after the discharge. Shot history effects (integrated particle recycling behaviour from the plasma facing surfaces) are seen on that the critical particle flux is reducing

  6. Electron microscope investigations of activated chalcopyrite particles via the FLSmidth® ROL process

    DEFF Research Database (Denmark)

    Karcz, Adam Paul; Damø, Anne Juul; Illerup, Jytte Boll

    2017-01-01

    -conducting minerals with the benefit of increasing chemical reactivity and dissolution kinetics. In the FLSmidth® Rapid Oxidative Leach (ROL) process, leach kinetics are still further enhanced by combining chemical and mechanical processes with the assistance of a Stirred Media Reactor. Due to the reduction...... in surface passivation problems associated with atmospheric leaching, this process is typically able to achieve copper recoveries exceeding 95% in 6 h. An important factor contributing to this extraordinary process performance is a mineral preconditioning step (the focus of this study), which uses between 0...... chemical activation and deformation of the chalcopyrite crystal lattice through the use of electron microscopy. Although the activation process took only an hour and the extent of conversion was on the order of a few mol%, the lattice was found to be strained throughout the particle. This paper draws some...

  7. Processing and characterization of activated carbon coated magnetic particles for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Ramanujan, R.V. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)]. E-mail: ramanujan@ntu.edu.sg; Purushotham, S. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Chia, M.H. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2007-05-16

    Synthesis and characterization of Magnetically Targeted Carrier (MTC) powders consisting of activated carbon coated iron particles were carried out. Powders with activated carbon content of 5% by weight (Fe5C) and 35% by weight (Fe35C) were studied. Powders were synthesized via the high energy ball milling route, and the influence of milling time on the morphology, magnetic properties and drug adsorption and desorption characteristics was investigated. Physical and structural characterization included electron microscopy, size analysis, and X-ray diffraction. The magnetic properties, and theophylline adsorption and desorption characteristics were studied. Fe35C milled for 10 h was found to be a suitable candidate for MTC applications with fine size, stable magnetic properties, and superior drug adsorption and desorption behavior.

  8. Exhaust System Reinforced by Jet Flow

    DEFF Research Database (Denmark)

    Pedersen, Lars Germann; Nielsen, Peter V.

    Since 1985 the University of Aalborg and Nordfab A/S have been working on an exhaust principle which is quite different from traditional exhaust systems. The REEXS principle (Reinforced Exhaust System), which originally was designed for the agricultural sector, is particularly well......-suited for industrial ventilation purposes. With the REEXS principle it is possible to create a flow pattern in front of the exhaust opening which will have a considerable influence on the general flow in a given room....

  9. High Temperature Resistant Exhaust Valve Spindle

    DEFF Research Database (Denmark)

    Bihlet, Uffe Ditlev

    of the engine, new high temperature alloys are required for a specific engine component, the exhaust valve spindle. Two alloys are used for an exhaust valve spindle; one for the bottom of the spindle, and one for the spindle seat. Being placed in the exhaust gas stream, combustion products such as V2O5 and Na2...

  10. Exhaustion, immuno-inflammation, and pathogen burden after cardiac surgery: an exploratory study.

    Science.gov (United States)

    Miller, Pamela S; Evangelista, Lorraine S; Giger, Joyce Newman; Martinez-Maza, Otoniel; Corvera-Tindel, Teresita; Magpantay, Larry; Pena, Guadalupe; Doering, Lynn V

    2014-06-01

    Exhaustion, a consequence of prolonged stress characterized by unusual fatigue, is associated with increased risk of cardiac morbidity and mortality. In patients recovering from coronary artery bypass (CABG), little is known about the relationship of 1) immune-mediated inflammation and resultant endothelial activation, and 2) cumulative exposure to infectious pathogens (pathogen burden (PB)) implicated in coronary atherosclerosis to exhaustion. The aim of this exploratory study was to investigate the association of PB, inflammatory markers (interleukin (IL)-6, IL-10) and a marker of endothelial activation (soluble intercellular adhesion molecule-1 (sICAM-1)) to exhaustion. One to two months post-CABG, 42 individuals who met inclusion criteria were assessed for exhaustion using the Maastricht Interview for Vital Exhaustion. Serum IgG antibodies to herpes simplex virus (HSV)-1, HSV-2, cytomegalovirus, Epstein Barr virus, and inflammatory and endothelial activation markers were measured by enzyme-linked immunosorbent assay. Pathogen burden was defined as the total number of seropositive exposures: low (0-1), moderate (2-3), and high (4). Prevalence of exhaustion was 40.5%. Relative to non-exhausted patients, exhausted patients demonstrated a higher frequency of moderate PB (h=0.73, p=0.04) but lower frequency of high PB (h=1.05, p=0.03). Exhaustion showed a non-significant trend for positive correlations with IL-6 and sICAM-1 levels, and inverse relation to PB. In subgroup analysis, exhausted patients had stronger correlations with IL-6 and IL-6:IL-10 and a tendency towards higher serum IL-10 concentrations compared with their non-exhausted counterparts. This hypothesis-generating study provides preliminary evidence that elevated post-CABG exhaustion may be associated with PB, inflammation, and endothelial activation.

  11. Understanding the adsorption interface of polyelectrolyte coating on redox active nanoparticles using soft particle electrokinetics and its biological activity.

    Science.gov (United States)

    Saraf, Shashank; Neal, Craig J; Das, Soumen; Barkam, Swetha; McCormack, Rameech; Seal, Sudipta

    2014-04-23

    The application of cerium oxide nanoparticles (CNPs) for therapeutic purposes requires a stable dispersion of nanoparticles in a biological environment. The objective of this study is to tailor the properties of polyelectrolyte coated CNPs as a function of molecular weight to achieve a stable and catalytic active dispersion. The coating of CNPs with polyacrylic acid (PAA) has increased the dispersion stability of CNPs and enhanced the catalytic ability. The stability of PAA coating was analyzed using the change in the Gibbs free energy computed by the Langmuir adsorption model. The adsorption isotherms were determined using soft particle electrokinetics which overcomes the challenges presented by other techniques. The change in Gibbs free energy was highest for CNPs coated with PAA of 250 kg/mol indicating the most stable coating. The change in free energy for PAA of 100 kg/mol coated CNPs was 85% lower than the PAA of 250 kg/mol coated CNPs. This significant difference is caused by the strong adsorption of PAA of 100 kg/mol on CNPs. Catalytic activity of PAA-CNPs is assessed by the catalase enzymatic mimetic activity of nanoparticles. The catalase activity was higher for PAA coated CNPs as compared to bare CNPs which indicated preferential adsorption of hydrogen peroxide induced by coating. This indicates that the catalase activity is also affected by the structure of the coating layer.

  12. US Department of Energy - Office of FreedomCar and Vehicle Technologies and US Centers for Disease Control and Prevention - National Institute for Occupational Safety and Health Inter-Agency Agreement Research on "The Analysis of Genotoxic Activities of Exhaust Emissions from Mobile Natural Gas, Diesel, and Spark-Ignition Engines"

    Energy Technology Data Exchange (ETDEWEB)

    William E. Wallace

    2006-09-30

    The US Department of Energy-Office of Heavy Vehicle Technologies (now the DOE-Office of FreedomCar and Vehicle Technologies) signed an Interagency Agreement (IAA) with National Institute for Occupational Safety and Health (NIOSH), No.01-15 DOE, 9/4/01, for 'The analysis of genotoxic activities of exhaust emissions from mobile natural gas, diesel, and spark-ignition engines'; subsequently modified on 3/27/02 (DOE IAG No.01-15-02M1); subsequently modified 9/02/03 (IAA Mod No. 01-15-03M1), as 'The analysis of genotoxic activities of exhaust emissions from mobile internal combustion engines: identification of engine design and operational parameters controlling exhaust genotoxicity'. The DOE Award/Contract number was DE-AI26-01CH11089. The IAA ended 9/30/06. This is the final summary technical report of National Institute for Occupational Safety and Health research performed with the US Department of Energy-Office of FreedomCar and Vehicle Technologies under that IAA: (A) NIOSH participation was requested by the DOE to provide in vitro genotoxicity assays of the organic solvent extracts of exhaust emissions from a suite of in-use diesel or spark-ignition vehicles; (B) research also was directed to develop and apply genotoxicity assays to the particulate phase of diesel exhaust, exploiting the NIOSH finding of genotoxicity expression by diesel exhaust particulate matter dispersed into the primary components of the surfactant coating the surface of the deep lung; (C) from the surfactant-dispersed DPM genotoxicity findings, the need for direct collection of DPM aerosols into surfactant for bioassay was recognized, and design and developmental testing of such samplers was initiated.

  13. Effect of the relationship between particle size, inter-particle distance, and metal loading of carbon supported fuel cell catalysts on their catalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Gon Corradini, Patricia; Pires, Felipe I.; Paganin, Valdecir A.; Perez, Joelma, E-mail: jperez@iqsc.usp.br [Instituto de Quimica de Sao Carlos, USP (Brazil); Antolini, Ermete [Scuola di Scienza dei Materiali (Italy)

    2012-09-15

    The effect of the relationship between particle size (d), inter-particle distance (x{sub i}), and metal loading (y) of carbon supported fuel cell Pt or PtRu catalysts on their catalytic activity, based on the optimum d (2.5-3 nm) and x{sub i}/d (>5) values, was evaluated. It was found that for y < 30 wt%, the optimum values of both d and x{sub i}/d can be always obtained. For y {>=} 30 wt%, instead, the positive effect of a thinner catalyst layer of the fuel cell electrode than that using catalysts with y < 30 wt% is concomitant to a decrease of the effective catalyst surface area due to an increase of d and/or a decrease of x{sub i}/d compared to their optimum values, with in turns gives rise to a decrease in the catalytic activity. The effect of the x{sub i}/d ratio has been successfully verified by experimental results on ethanol oxidation on PtRu/C catalysts with same particle size and same degree of alloying but different metal loading. Tests in direct ethanol fuel cells showed that, compared to 20 wt% PtRu/C, the negative effect of the lower x{sub i}/d on the catalytic activity of 30 and 40 wt% PtRu/C catalysts was superior to the positive effect of the thinner catalyst layer.

  14. Synthesis and characterization of Gold and Silver nano-particles using different leaf extracts namely Catharanthus roseus, Datura metel and Azadirachta indica and Estimation of antimicrobial activity of silver nano-particles using disc diffusion method

    OpenAIRE

    Sarbjeet Singh Gujral

    2014-01-01

    Objective: synthesis of gold and silver nano-particles using leaf extracts of Catharanthus roseus, Datura metel and Azadirachta indica and Estimation of antimicrobial activity of silver nano-particles using disc diffusion method. Method: Green approach has been utilized for the synthesis of gold and silver nano-particles. Different aqueous plant extracts has been prepared which was then utilized for the biosynthesis of gold and silver nano-particles. Estimation for the synthesis of nano-parti...

  15. Extra-fine particle inhaled corticosteroids, pharma-cokinetics and systemic activity in children with asthma.

    Science.gov (United States)

    Wolthers, Ole D

    2016-02-01

    During recent years, extra-fine particle inhaled corticosteroids with a median aerodynamic diameter ≤2 μm have been introduced in the treatment of asthma. The aim of this paper was to review pharmacokinetics and systemic activity of extra-fine particle hydroalkane pressurized metered dose inhaled (pMDI) ciclesonide and beclomethasone dipropionate in children. A literature review was performed. Systemic bioavailability of oral and pulmonary deposition of extra-fine ciclesonide and beclomethasone dipropionate was 52% and 82%, the half-life in serum 3.2 and 1.5 h and first-pass hepatic metabolism >99% and 60%, respectively. Secondary analyses of urine cortisol/creatinine excretion found no effects of ciclesonide pMDI between 40 and 320 μg/day or of beclomethasone dipropionate pMDI between 80 and 400 μg/day. Ciclesonide pMDI 40, 80 and 160 μg/day caused no effects on short-term lower leg growth rate as assessed by knemometry. Ciclesonide 320 μg/day was associated with a numerically short-term growth suppression equivalent to 30% which was similar to 25% and 36% suppression caused by beclomethasone dipropionate HFA and CFC 200 μg/day, respectively. Consistent with the differences in key pharmacokinetic features, beclomethasone dipropionate is associated with a systemic activity detected by knemometry at a lower dose than ciclesonide. Whether that correlates with a clinically important difference remains to be explored. Assessments of systemic activity of beclomethasone dipropionate 180 μg/day as well as head-to-head comparisons are warranted. Preferably, such studies should apply the sensitive method of knemometry. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Electrophysiologic Study of Exhaustive Exercise

    Directory of Open Access Journals (Sweden)

    MA Babaee Bigi

    2010-12-01

    Full Text Available Background: Exhaustive exercise is well known to pose a variety ofhealth hazards, such as sudden cardiac death reported in ultra-marathon runners.Depressed parasympathetic tone is associated with increased risk of suddencardiac death, thus parasympathetic withdrawal in post-exercise phase may be ahigh risk period for sudden death. To date, the effect on cardiacelectrophysiology after exhaustive strenuous exercise has not been described.The aim of this study was to evaluate the impact of severe exhaustive exerciseon cardiac electrophysiology.Methods: The subjects in ranger training were invited to participatein this prospective study. The parameters measured consisted of PR interval, QRSduration, and macro T wave alternans as well as corrected QT, QTc dispersion,Tpeak –Tend interval and Tpeak –Tend dispersion.Results: The study group consisted of 40 consecutive male rangers whocompleted training and the control group (22 healthy age and height matched malesubjects. In regard to electrocardiographic criteria, no differences were foundbetween rangers before and after training program. In respect of therepolarization markers, there were no significant differences between therangers before and after training program.

  17. Experimental investigation of mesoscopic heterogeneous motion of laser-activated self-propelling Janus particles in suspension

    Science.gov (United States)

    Io, Chong-Wai; Chen, Tzu-Yin; Yeh, Jai-Wei; Cai, Sin-Cen

    2017-12-01

    The mesoscopic collective motion of self-propelling active particle suspension is experimentally investigated. The active particles are silica micro spheres with Au hemisphere coating, and their propelling strength is activated by laser irradiation. The suspension is driven from equilibrium to near equilibrium and far from equilibrium by tuning the excitation laser intensity. By use of the long-term particle tracking technique, the time evolution of a large amount of active particles is resolvable. For low laser intensity, the suspension is driven to near equilibrium state with homogeneous superdiffusion motion. The strength of enhanced superdiffusion is monotonically related to the laser intensity. For high laser intensity, the motility-induced phase separation with the coexistence of dense cluster and very dilute individual particle are observed. It leads to highly heterogeneous dynamic with less mobile jammed cluster and fast-moving particles and subsequently suppresses the enhanced superdiffusion. Such heterogeneous dynamics is similar to many far from equilibrium systems. Finally, the degree away from equilibrium (Gaussian dynamics) triggered by propelling strength is quantified by non-Gaussian parameters.

  18. A battery model that enables consideration of realistic anisotropic environment surrounding an active material particle and its application

    Science.gov (United States)

    Lin, Xianke; Lu, Wei

    2017-07-01

    This paper proposes a model that enables consideration of the realistic anisotropic environment surrounding an active material particle by incorporating both diffusion and migration of lithium ions and electrons in the particle. This model makes it possible to quantitatively evaluate effects such as fracture on capacity degradation. In contrast, the conventional model assumes isotropic environment and only considers diffusion in the active particle, which cannot capture the effect of fracture since it would predict results contradictory to experimental observations. With the developed model we have investigated the effects of active material electronic conductivity, particle size, and State of Charge (SOC) swing window when fracture exists. The study shows that the low electronic conductivity of active material has a significant impact on the lithium ion pattern. Fracture increases the resistance for electron transport and therefore reduces lithium intercalation/deintercalation. Particle size plays an important role in lithium ion transport. Smaller particle size is preferable for mitigating capacity loss when fracture happens. The study also shows that operating at high SOC reduces the impact of fracture.

  19. Method for generating a highly reactive plasma for exhaust gas aftertreatment and enhanced catalyst reactivity

    Science.gov (United States)

    Whealton, John H.; Hanson, Gregory R.; Storey, John M.; Raridon, Richard J.; Armfield, Jeffrey S.; Bigelow, Timothy S.; Graves, Ronald L.

    2002-01-01

    A method for non-thermal plasma aftertreatment of exhaust gases the method comprising the steps of providing short risetime, high frequency, high power bursts of low-duty factor microwaves sufficient to generate a plasma discharge and passing a gas to be treated through the discharge so as to cause dissociative reduction of the exhaust gases and enhanced catalyst reactivity through application of the pulsed microwave fields directly to the catalyst material sufficient to cause a polarizability catastrophe and enhanced heating of the metal crystallite particles of the catalyst, and in the presence or absence of the plasma. The invention also includes a reactor for aftertreatment of exhaust gases.

  20. Integrated analysis of particle interactions at hadron colliders Report of research activities in 2010-2015

    Energy Technology Data Exchange (ETDEWEB)

    Nadolsky, Pavel M. [Southern Methodist Univ., Dallas, TX (United States)

    2015-08-31

    The report summarizes research activities of the project ”Integrated analysis of particle interactions” at Southern Methodist University, funded by 2010 DOE Early Career Research Award DE-SC0003870. The goal of the project is to provide state-of-the-art predictions in quantum chromodynamics in order to achieve objectives of the LHC program for studies of electroweak symmetry breaking and new physics searches. We published 19 journal papers focusing on in-depth studies of proton structure and integration of advanced calculations from different areas of particle phenomenology: multi-loop calculations, accurate long-distance hadronic functions, and precise numerical programs. Methods for factorization of QCD cross sections were advanced in order to develop new generations of CTEQ parton distribution functions (PDFs), CT10 and CT14. These distributions provide the core theoretical input for multi-loop perturbative calculations by LHC experimental collaborations. A novel ”PDF meta-analysis” technique was invented to streamline applications of PDFs in numerous LHC simulations and to combine PDFs from various groups using multivariate stochastic sampling of PDF parameters. The meta-analysis will help to bring the LHC perturbative calculations to the new level of accuracy, while reducing computational efforts. The work on parton distributions was complemented by development of advanced perturbative techniques to predict observables dependent on several momentum scales, including production of massive quarks and transverse momentum resummation at the next-to-next-to-leading order in QCD.

  1. Quantitative structure-activity relationships for green algae growth inhibition by polymer particles.

    Science.gov (United States)

    Nolte, Tom M; Peijnenburg, Willie J G M; Hendriks, A Jan; van de Meent, Dik

    2017-07-01

    After use and disposal of chemical products, many types of polymer particles end up in the aquatic environment with potential toxic effects to primary producers like green algae. In this study, we have developed Quantitative Structure-Activity Relationships (QSARs) for a set of highly structural diverse polymers which are capable to estimate green algae growth inhibition (EC50). The model (N = 43, R 2  = 0.73, RMSE = 0.28) is a regression-based decision tree using one structural descriptor for each of three polymer classes separated based on charge. The QSAR is applicable to linear homo polymers as well as copolymers and does not require information on the size of the polymer particle or underlying core material. Highly branched polymers, non-nitrogen cationic polymers and polymeric surfactants are not included in the model and thus cannot be evaluated. The model works best for cationic and non-ionic polymers for which cellular adsorption, disruption of the cell wall and photosynthesis inhibition were the mechanisms of action. For anionic polymers, specific properties of the polymer and test characteristics need to be known for detailed assessment. The data and QSAR results for anionic polymers, when combined with molecular dynamics simulations indicated that nutrient depletion is likely the dominant mode of toxicity. Nutrient depletion in turn, is determined by the non-linear interplay between polymer charge density and backbone flexibility. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Physical activity versus sedentary behavior: associations with lipoprotein particle subclass concentrations in healthy adults.

    Directory of Open Access Journals (Sweden)

    Eivind Aadland

    Full Text Available BACKGROUND: Physical activity (PA and sedentary behavior (SED may have independent effects on health and disease. This might be due to PA and SED having distinct effects on lipoprotein metabolism. The aim of this study was to determine associations between lipoprotein subclass particle concentrations (-P and accelerometer-measured SED and moderate-to-vigorous PA (MVPA in a sample of healthy adult subjects. METHODS: Lipoprotein subclass particle concentrations were determined by proton nuclear magnetic resonance spectroscopy, whereas SED and MVPA were measured using Agtigraph GT1M and GT3X+ accelerometers. We obtained valid data in 73 subjects (30 men and 43 women, age 40.5 ± 10.6 years; body mass index 24.0 ± 2.8. Multiple regression analysis was used to determine associations (partial correlations with lipoproteins. RESULTS: Positive associations were detected between SED and small VLDL-P, large LDL-P and TG (partial r = 0.24 to 0.25, p .355. On the contrary, MVPA was positively associated with large HDL-P, average HDL size, Apo A1 and HDL-cholesterol (partial r = 0.28 to 0.50, p .607. CONCLUSION: There might be a specific effect of SED versus MVPA on lipoprotein metabolism. However, our results must be interpreted carefully due to possible effect-modification by gender and a low sample size. Thus, our findings should be viewed as preliminary.

  3. Plant virus particles carrying tumour antigen activate TLR7 and Induce high levels of protective antibody.

    Directory of Open Access Journals (Sweden)

    Jantipa Jobsri

    Full Text Available Induction of potent antibody is the goal of many vaccines targeted against infections or cancer. Modern vaccine designs that use virus-like particles (VLP have shown efficacy for prophylactic vaccination against virus-associated cancer in the clinic. Here we used plant viral particles (PVP, which are structurally analogous to VLP, coupled to a weak idiotypic (Id tumour antigen, as a conjugate vaccine to induce antibody against a murine B-cell malignancy. The Id-PVP vaccine incorporates a natural adjuvant, the viral ssRNA, which acts via TLR7. It induced potent protective anti-Id antibody responses in an in vivo mouse model, superior to the "gold standard" Id vaccine, with prevalence of the IgG2a isotype. Combination with alum further increased antibody levels and maintained the IgG2a bias. Engagement of TLR7 in vivo was followed by secretion of IFN-α by plasmacytoid dendritic cells and by activation of splenic CD11chi conventional dendritic cells. The latter was apparent from up-regulation of co-stimulatory molecules and from secretion of a wide range of inflammatory cytokines and chemokines including the Th1-governing cytokine IL-12, in keeping with the IgG2a antibody isotype distribution. PVP conjugates are a novel cancer vaccine design, offering an attractive molecular form, similar to VLP, and providing T-cell help. In contrast to VLP, they also incorporate a safe "in-built" ssRNA adjuvant.

  4. Active and fast particle driven Alfvén eigenmodes in Alcator C-Moda)

    Science.gov (United States)

    Snipes, J. A.; Basse, N.; Boswell, C.; Edlund, E.; Fasoli, A.; Gorelenkov, N. N.; Granetz, R. S.; Lin, L.; Lin, Y.; Parker, R.; Porkolab, M.; Sears, J.; Sharapov, S.; Tang, V.; Wukitch, S.

    2005-05-01

    Alfvén eigenmodes (AEs) are studied to assess their stability in high density reactor relevant regimes where Ti≈Te and as a diagnostic tool. Stable AEs are excited with active magnetohydrodynamics antennas in the range of the expected AE frequency. Toroidal Alfvén eigenmode (TAE) damping rates between 0.5%<γ/ω<4.5% have been observed in diverted and limited Ohmic plasmas. Unstable AEs are excited with a fast ion tail driven by H minority ion cyclotron radio frequency (ICRF) heating with electron densities in the range of n¯e=0.5-2×1020m-3. Energetic particle modes or TAEs have been observed to decrease in frequency and mode number with time up to a large sawtooth collapse, indicating the role fast particles play in stabilizing sawteeth. In the current rise phase, unstable modes with frequencies that increase rapidly with time are observed with magnetic pick-up coils at the wall and phase contrast imaging density fluctuation measurements in the core. Modeling of these modes constrains the calculated safety factor profile to be very flat or with slightly reversed shear. AEs are found to be more stable for an inboard than for central or outboard ICRF resonances in qualitative agreement with modeling.

  5. Chemical aging of single and multicomponent biomass burning aerosol surrogate particles by OH: implications for cloud condensation nucleus activity

    Science.gov (United States)

    Slade, J. H.; Thalman, R.; Wang, J.; Knopf, D. A.

    2015-09-01

    Multiphase OH and O3 oxidation reactions with atmospheric organic aerosol (OA) can influence particle physicochemical properties including composition, morphology, and lifetime. Chemical aging of initially insoluble or low-soluble single-component OA by OH and O3 can increase their water solubility and hygroscopicity, making them more active as cloud condensation nuclei (CCN) and susceptible to wet deposition. However, an outstanding problem is whether the effects of chemical aging on their CCN activity are preserved when mixed with other organic or inorganic compounds exhibiting greater water solubility. In this work, the CCN activity of laboratory-generated biomass burning aerosol (BBA) surrogate particles exposed to OH and O3 is evaluated by determining the hygroscopicity parameter, κ, as a function of particle type, mixing state, and OH and O3 exposure applying a CCN counter (CCNc) coupled to an aerosol flow reactor (AFR). Levoglucosan (LEV), 4-methyl-5-nitrocatechol (MNC), and potassium sulfate (KS) serve as representative BBA compounds that exhibit different hygroscopicity, water solubility, chemical functionalities, and reactivity with OH radicals, and thus exemplify the complexity of mixed inorganic/organic aerosol in the atmosphere. The CCN activities of all of the particles were unaffected by O3 exposure. Following exposure to OH, κ of MNC was enhanced by an order of magnitude, from 0.009 to ~ 0.1, indicating that chemically aged MNC particles are better CCN and more prone to wet deposition than pure MNC particles. No significant enhancement in κ was observed for pure LEV particles following OH exposure. κ of the internally mixed particles was not affected by OH oxidation. Furthermore, the CCN activity of OH-exposed MNC-coated KS particles is similar to the OH unexposed atomized 1 : 1 by mass MNC : KS binary-component particles. Our results strongly suggest that when OA is dominated by water-soluble organic carbon (WSOC) or inorganic ions, chemical

  6. Chemical aging of single and multicomponent biomass burning aerosol surrogate-particles by OH: implications for cloud condensation nucleus activity

    Science.gov (United States)

    Slade, J. H.; Thalman, R.; Wang, J.; Knopf, D. A.

    2015-03-01

    Multiphase OH and O3 oxidation reactions with atmospheric organic aerosol (OA) can influence particle physicochemical properties including composition, morphology, and lifetime. Chemical aging of initially insoluble or low soluble single-component OA by OH and O3 can increase their water-solubility and hygroscopicity, making them more active as cloud condensation nuclei (CCN) and susceptible to wet deposition. However, an outstanding problem is whether the effects of chemical aging on their CCN activity are preserved when mixed with other organic or inorganic compounds exhibiting greater water-solubility. In this work, the CCN activity of laboratory-generated biomass burning aerosol (BBA) surrogate-particles exposed to OH and O3 is evaluated by determining the hygroscopicity parameter, κ, as a function of particle type, mixing state, and OH/O3 exposure applying a CCN counter (CCNc) coupled to an aerosol flow reactor (AFR). Levoglucosan (LEV), 4-methyl-5-nitrocatechol (MNC), and potassium sulfate (KS) serve as representative BBA compounds that exhibit different hygroscopicity, water solubility, chemical functionalities, and reactivity with OH radicals, and thus exemplify the complexity of mixed inorganic/organic aerosol in the atmosphere. The CCN activities of all of the particles were unaffected by O3 exposure. Following exposure to OH, κ of MNC was enhanced by an order of magnitude, from 0.009 to ~0.1, indicating that chemically-aged MNC particles are better CCN and more prone to wet deposition than pure MNC particles. No significant enhancement in κ was observed for pure LEV particles following OH exposure. κ of the internally-mixed particles was not affected by OH oxidation. Furthermore, the CCN activity of OH exposed MNC-coated KS particles is similar to the OH unexposed atomized 1 : 1 by mass MNC : KS binary-component particles. Our results strongly suggest that when OA is dominated by water-soluble organic carbon (WSOC) or inorganic ions, chemical aging

  7. Re-activation of degraded nickel cermet anodes - Nano-particle formation via reverse current pulses

    Science.gov (United States)

    Hauch, A.; Marchese, M.; Lanzini, A.; Graves, C.

    2018-02-01

    The Ni/yttria-stabilized-zirconia (YSZ) cermet is the most commonly applied fuel electrode for solid oxide cells (SOCs). Loss of Ni/YSZ electrode activity is a key life-time limiting factor of the SOC. Developing means to mitigate this loss of performance or re-activate a fuel electrode is therefore important. In this work, we report a series of five tests on state-of-the-art Ni/YSZ-YSZ-CGObarrier-LSC/CGO cells. All cells were deliberately degraded via gas stream impurities in CO2/CO or harsh steam electrolysis operation. The cells were re-activated via a variety of reverse current treatments (RCTs). Via electrochemical impedance spectroscopy, we found that the Ni/YSZ electrode performance could be recovered via RCT, but not via constant fuel cell operation. For optimized RCT, we obtained a lower Ni/YSZ electrode resistance than the initial resistance. E.g. at 700 °C we measured fuel electrode resistance of 180 mΩ cm2, 390 mΩ cm2, and 159 mΩ cm2 before degradation, after degradation and after re-activation via RCT, respectively. Post-test SEM revealed that the RCT led to formation of nano-particles in the fuel electrode. Besides the remarkable improvement, the results also showed that RCTs can weaken Ni/YSZ interfaces and the electrode/electrolyte interface. This indicates that finding an optimum RCT profile is crucial for achieving maximum benefit.

  8. Exhaustion measured by the SF-36 vitality scale is associated with a flattened diurnal cortisol profile

    DEFF Research Database (Denmark)

    Lindeberg, Sara I; Eek, Frida; Lindbladh, Eva

    2008-01-01

    The possible association between stress-related exhaustion and reduced activity in the hypothalamo-pituitary-adrenal (HPA) axis is increasingly in focus. The aim of the present study was to examine whether exhaustion measured in a non-patient population is associated with alterations in diurnal...... cortisol profile. The study population included 78 working individuals. The study group was dichotomised into exhausted and non-exhausted groups by means of the SF-36 vitality scale. Salivary cortisol was measured at three times during 1 workday: at awakening, 30min after awakening, and in the evening....... The results showed that diurnal cortisol variation was significantly reduced in exhausted individuals. The difference in cortisol variation was mainly due to lowered morning cortisol in the exhausted group. Differences in cortisol levels at each sampling time or in mean diurnal output of cortisol were...

  9. Anatomical and physiological responses of Colorado blue spruce to vehicle exhausts.

    Science.gov (United States)

    Qin, Xuebo; Sun, Nan; Ma, Lixin; Chang, Yingqiao; Mu, Liqiang

    2014-09-01

    In order to examine whether the leaves of the Colorado blue spruce (Picea pungens) are damaged or not by traffic pollution, the traits of the anatomy and physiology of its leaves are investigated by exposure to vehicle exhausts in a laboratory experiment lasting 30 days. The results show that both the anatomical structures and physiological traits of the leaves are significantly affected by vehicle exhausts. The anatomical structures, including epidermis, cuticle, palisade, and spongy parenchyma are modified when exposed to the high concentrations (≥ 0.4 mg/m(3)) of vehicle exhausts. However, physiological traits such as total chlorophyll content are not changed when exposed to different concentrations of vehicle exhaust. Unlike the total chlorophyll content, the electrical conductivities increased, whereas the POD activities decreased when presented in vehicle exhausts. The present study indicates that the Colorado blue spruce changes its anatomical structures and physiological traits to avoid possible damage by vehicle exhausts.

  10. Reduction of diesel engine emissions through the recirculation of cooled exhaust gas; Senkung von Diesel-Emissionen durch Rueckfuehrung von gekuehltem Abgas

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, R. [Behr GmbH und Co., Stuttgart (Germany). Entwicklungsteam Abgaswaermeuebertrager

    1997-09-01

    More stringent exhaust regulations for diesel engines which will come into force in Europe (Euro III, 1999) and the USA (2004) will necessitate new methods of reducing emissions, one of which entails the recirculation of cooled exhaust gas. By this process, a certain volume of the exhaust gas is bled off upstream of the turbine, cooled by the engine coolant and remixed with the combustion air down-stream of the intercooler. By contrast with other methods of exhaust gas purification, such as a lean-NO{sub x} catalytic converter, this process needs no second activating agent, such as urea, and, in comparison with a modification of the combustion process, only slightly more fuel. The heat transfer system developed by Behr, which uses the engine coolant to cool the exhaust gas, is capable of withstanding the high temperatures and pressures in the forward section of the exhaust system, is resistant to the sulphuric acid in diesel condensation and, despite its compact design, exhibits a low level of flow resistance. Its exceptional cooling capacity is achieved by a new heat transfer system employing `winglet` turbulence generators. These reduce deposits of soot and other particles on the walls of the heat exchanger to a considerable extent, thereby contributing to its long-term efficiency. (orig.) [Deutsch] Durch die Einfuehrung neuer, strengerer Abgasvorschriften fuer Dieselmotoren 1999 in Europa und 2004 in den USA ruecken neue Techniken zur Emissionssenkung ins Blickfeld. Eine davon ist die gekuehlte Abgasrueckfuehrung, die eine Emissionssenkung bei nur minimalem Anstieg des Kraftstoffverbrauchs erlaubt. An den Waermeuebertrager fuer solch ein System werden hinsichtlich kompakter Bauweise und Leistung, Temperaturbestaendigkeit, Verschutzungs-Unempfindlichkeit und Korrosionsbestaendigkeit hohe Anforderungen gestellt. Der von Behr entwickelte Abgas-Kuehlmittel-Waermeuebertrager erfuellt diese Anforderungen und zeichnet sich durch eine hohe Leistungsdichte aus. Dies

  11. Particle image velocimetry of active flow control on a compressor cascade

    Energy Technology Data Exchange (ETDEWEB)

    Hecklau, M.; Rennings, R. van; Zander, V.; Nitsche, W. [Technische Universitaet Berlin, Department of Aeronautics and Astronautics, Berlin (Germany); Huppertz, A.; Swoboda, M. [Rolls-Royce Deutschland Ltd. and Co. KG, Dahlewitz (Germany)

    2011-04-15

    AFC (Active Flow Control) experiments have been performed by means of steady and pulsed blowing out of the sidewalls as well as out of the blade's suction surface in a highly loaded compressor cascade. PIV (Particle Image Velocimetry) was used to evaluate the fully three-dimensional internal flow field and the impact of AFC methods. The aim was to observe the secondary flow structures and flow instabilities by PIV, to tune the AFC device operation parameters. This paper summarizes the different PIV measurements performed at the stator cascade to give an overview of the dominant flow features in the passage flow field and to obtain a detailed view of control mechanisms. In addition, a new vortex detection method is presented, based on a 2D-wavelet which is applicable in two-dimensional velocity data fields. (orig.)

  12. Hybrid Particle Swarm Optimization for Hybrid Flowshop Scheduling Problem with Maintenance Activities

    Directory of Open Access Journals (Sweden)

    Jun-qing Li

    2014-01-01

    Full Text Available A hybrid algorithm which combines particle swarm optimization (PSO and iterated local search (ILS is proposed for solving the hybrid flowshop scheduling (HFS problem with preventive maintenance (PM activities. In the proposed algorithm, different crossover operators and mutation operators are investigated. In addition, an efficient multiple insert mutation operator is developed for enhancing the searching ability of the algorithm. Furthermore, an ILS-based local search procedure is embedded in the algorithm to improve the exploitation ability of the proposed algorithm. The detailed experimental parameter for the canonical PSO is tuning. The proposed algorithm is tested on the variation of 77 Carlier and Néron’s benchmark problems. Detailed comparisons with the present efficient algorithms, including hGA, ILS, PSO, and IG, verify the efficiency and effectiveness of the proposed algorithm.

  13. Hybrid particle swarm optimization for hybrid flowshop scheduling problem with maintenance activities.

    Science.gov (United States)

    Li, Jun-qing; Pan, Quan-ke; Mao, Kun

    2014-01-01

    A hybrid algorithm which combines particle swarm optimization (PSO) and iterated local search (ILS) is proposed for solving the hybrid flowshop scheduling (HFS) problem with preventive maintenance (PM) activities. In the proposed algorithm, different crossover operators and mutation operators are investigated. In addition, an efficient multiple insert mutation operator is developed for enhancing the searching ability of the algorithm. Furthermore, an ILS-based local search procedure is embedded in the algorithm to improve the exploitation ability of the proposed algorithm. The detailed experimental parameter for the canonical PSO is tuning. The proposed algorithm is tested on the variation of 77 Carlier and Néron's benchmark problems. Detailed comparisons with the present efficient algorithms, including hGA, ILS, PSO, and IG, verify the efficiency and effectiveness of the proposed algorithm.

  14. Activation energy of etching for CR-39 as a function of linear energy transfer of the incident particles

    CERN Document Server

    Awad, E M

    1999-01-01

    In this work, we have studied the effect of the radiation damage caused by the incident particles on the activation energy of etching for CR-39 samples. The damage produced by the incident particle is expressed in terms of the linear energy transfer (LET). CR-39 samples from American Acrylic were irradiated to three different LET particles. These are N (LET sub 2 sub 0 sub 0 = 20 KeV/mu m) as a light particle, Fe (LET sub 2 sub 0 sub 0 = 110 KeV/mu m) as a medium particle and fission fragments (ff) from a sup 2 sup 5 sup 2 Cf source as heavy particles. In general the bulk etch rate was calculated using the weight difference method and the track etch rate was determined using the track geometry at various temperatures (50-90 deg. C) and concentrations (4-9 N) of the NaOH etchant. The average activation energy E sub b related to the bulk etch rate v sub b was calculated from 1n v sub b vs. 1/T. The average activation energy E sub t related to the track etch rate v sub t was estimated from 1n v sub t vs. 1/T. It...

  15. Measurement of alkali vapors in PFBC exhaust. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.H.D.; Swift, W.M.

    1994-01-01

    Under the auspices of the US Department of Energy through Morgantown Energy Technology Center, laboratory-scale studies were conducted to develop a regenerable activated-bauxite adsorbent (RABA) for use in an in situ regenerable activated-bauxite sorber alkali monitor (RABSAM). The RABSAM is a sampling probe that does not require a high-temperature/high-pressure sampling line for reliable measurement of alkali vapor in the exhaust of pressurized fluidized-bed combustor (PFBC). The RABA can be generated from the commercial grade activated bauxite by deactivating (or reacting) clay impurities in activated bauxite with NaCl or LiCl vapor. Under the atmospheric deactivation process, however, only a partial deactivation of clay impurities is achieved, probably due to limited access of NaCl or LiCl vapor into micropores of activated bauxite. Because LiCl vapor chemically reacts with alumina substrate of activated bauxite, resulting in pore enlargement, loss of pore surface area, and a decrease in the subsequent NaCl-vapor sorption capacity of the RABA, NaCl is a more suitable deactivation agent than LiCl vapor. In a simulated PFBC exhaust environment, the RABA behaves similarly to fresh activated bauxite in capturing NaCl vapor from the simulated PFBC exhaust. Based on results of this work, we recommend generating chemically and thermally stable RABA by deactivating clay impurities of commercial grade activated bauxite with NaCl or KCl vapor under simulated PFBC exhaust environment, that is, high-temperature, high-pressure, and high concentrations of NaCl or KCl vapor in simulated PFBC exhaust compositions.

  16. Effects of alfalfa particle size and specific gravity on chewing activity, digestibility, and performance of Holstein dairy cows.

    Science.gov (United States)

    Teimouri Yansari, A; Valizadeh, R; Naserian, A; Christensen, D A; Yu, P; Eftekhari Shahroodi, F

    2004-11-01

    Two experiments were carried out to test the effects of alfalfa particle size and functional specific gravity (FSG) on chewing activity, digestibility, rumen kinetics, and production of lactating dairy cows fed corn silage based rations. In experiment 1, water-holding capacity (WHC), insoluble dry matter, hydration rate, and FSG changes were determined in alfalfa hay (varying in particle size) and corn silage. Reduction of particle size increased bulk density, FSG, and the rate of hydration, and decreased WHC of alfalfa. In experiment 2, 9 midlactation Holstein dairy cows fed total mixed rations containing 3 sizes of alfalfa hay (with geometric mean 7.83, 4.04, and 1.14 mm) were used in a replicated 3 x 3 Latin square design. The diets contained 20, 20, 35, 7, 7.5, 10, 0.3, 0.1, and 0.1% of DM alfalfa, corn silage, barley, soybean meal, beet pulp, wheat bran, dicalcium phosphate, vitamin premix, and salt, respectively. The geometric means (GM) of rations were 3.34, 2.47, and 1.66 mm in long, medium, and fine alfalfa treatments, respectively. Reduction of particle size increased daily NDF intake (kg), but decreased the proportion of physically effective factor (pef) and physically effective NDF (peNDF) in the ingested rations. Reduction of particle size increased the FSG of rations and intake of DM but reduced digestibility of NDF and ash. Reduction of particle size decreased ruminal mean retention time (RMRT), but increased the ruminal particulate passage rate. Milk and FCM yield were not affected by treatments. The rumen pH, total chewing activity, rumination, eating time, and milk fat were reduced as particle size decreased, but milk protein increased. This study showed that reduction of forage particle size increased bulk density, FSG, and hydration rate of alfalfa and was the most influential factor affecting DMI, milk composition, and chewing behavior. Reduction of forage particle size had minimal impact on digestibility and milk production.

  17. Experimental and Numerical Studies of Particle Acceleration by an Active Microwave Medium

    CERN Document Server

    Schoessow, Paul

    2005-01-01

    There has been considerable theoretical work on the so-called PASER concept, in which a particle beam is accelerated directly by absorbing energy from an active medium, analogous to the amplification of an optical signal in a laser. Use of an active microwave (maser) medium would have the advantage of requiring relaxed beam quality (mm vs. nm characteristic beam dimensions). Recent work using electron paramagnetic resonance (EPR) techniques has demonstrated activity in the microwave regime (i.e. negative imaginary part of the magnetic susceptibility) for a class of organic compounds. A solution of fullerene (C60) in a liquid crystal solvent has been reported in the literature to possess a maser transition in the X-band region. An external DC magnetic field is required to obtain the effect; the frequency of the maser transition is adjustable by varying the magnetic field strength. We will report on the development of numerical and laboratory tools to evaluate the use of this material for accelerator applicatio...

  18. A distinct atomic structure-catalytic activity relationship in 3-10 nm supported Au particles.

    Science.gov (United States)

    Petkov, Valeri; Ren, Yang; Shan, Shiyao; Luo, Jin; Zhong, Chuan-Jian

    2014-01-07

    Bulk Au is very inert but Au nanoparticles less than 5 nm in size have been found to be catalytically active for several reactions, in particular for low-temperature oxidation of CO. Using high-energy X-ray diffraction coupled with atomic pair distribution function analysis and computer simulations we determine the structure of 3 nm and 10 nm Au particles supported on titania and silica as typical representatives of reducible and irreducible supports, respectively. We find that the synthesis protocol adopted in our work affects strongly and differently the structure of the Au nanoparticles on the different supports. This leads to clearly distinct dependences of the catalytic activity of the nanoparticles on their size. In the case of the silica support the catalytic activity of Au nanoparticles increases and in the case of the titania support it decreases with decreasing nanoparticle size. The experimental results are considered in terms of current theoretical predictions and found to be in good accord with them.

  19. Effects of nano-copper(II) oxide and nanomagnesium oxide particles on activated sludge.

    Science.gov (United States)

    Liu, Guoqiang; Wang, Jianmin

    2012-07-01

    Effects of nano-copper(II) oxide (nano-CuO) and nanomagnesium oxide (nano-MgO) particles on activated sludge endogenous respiration (aerobic digestion), biochemical oxygen demand (BOD) biodegradation, and nitrification were investigated through respiration rate measurement. For comparison, the effects of Cu(II) and Mg(II) ions on activated sludge were also studied. Results indicated that soluble Cu(II) has half maximum inhibitory concentration (IC50) values of 19, 5.5, 53, and 117 mg Cu/L for endogenous respiration, BOD biodegradation, ammonium oxidation, and nitrite oxidation, respectively. However, nano-CuO only inhibited BOD biodegradation at 240 mg Cu/L or more, and its associated toxicity was primarily caused by soluble Cu(II). In contrast, soluble Mg(II) was not toxic to activated sludge in the experimental concentration range, but nano-MgO inhibited BOD biodegradation and nitrification with IC50 values of 70 and 143 mg Mg/L, respectively. Further study indicated that the toxicity of nano-MgO resulted primarily from increased pH following MgO hydrolysis.

  20. Cloud droplet activation mechanisms of amino acid aerosol particles: insight from molecular dynamics simulations

    Directory of Open Access Journals (Sweden)

    Xin Li

    2013-07-01

    Full Text Available Atmospheric amino acids constitute a large fraction of water-soluble organic nitrogen compounds in aerosol particles, and have been confirmed as effective cloud condensation nuclei (CCN materials in laboratory experiments. We present a molecular dynamics (MD study of six amino acids with different structures and chemical properties that are relevant to the remote marine atmospheric aerosol–cloud system, with the aim of investigating the detailed mechanism of their induced changes in surface activity and surface tension, which are important properties for cloud drop activation. Distributions and orientations of the amino acid molecules are studied; these l-amino acids are serine (SER, glycine (GLY, alanine (ALA, valine (VAL, methionine (MET and phenylalanine (PHE and are categorised as hydrophilic and amphiphilic according to their affinities to water. The results suggest that the presence of surface-concentrated amphiphilic amino acid molecules give rise to enhanced Lennard–Jones repulsion, which in turn results in decreased surface tension of a planar interface and an increased surface tension of the spherical interface of droplets with diameters below 10 nm. The observed surface tension perturbation for the different amino acids under study not only serves as benchmark for future studies of more complex systems, but also shows that amphiphilic amino acids are surface active. The MD simulations used in this study reproduce experimental results of surface tension measurements for planar interfaces and the method is therefore applicable for spherical interfaces of nano-size for which experimental measurements are not possible to conduct.

  1. 20 CFR 636.5 - Exhaustion of grantee level procedure.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Exhaustion of grantee level procedure. 636.5..., INVESTIGATIONS AND HEARINGS § 636.5 Exhaustion of grantee level procedure. (a) Exhaustion required. No... have been exhausted. (b) Exhaustion exceptions. Complainants who have not exhausted the procedures at...

  2. Cloud droplet activation of mixed model HULIS and NaCl particles: Experimental results and κ-Köhler theory

    Science.gov (United States)

    Kristensen, Thomas B.; Prisle, Nønne L.; Bilde, Merete

    2014-02-01

    Significant amounts of humic-like substances (HULIS) are present in marine submicrometer particles. The cloud condensation nuclei (CCN) activation was investigated for marine model particles comprised of Nordic Aquatic Fulvic Acid Reference (NAFA) and sodium chloride (NaCl) in mass ratios of 100:0, 80:20, 50:50, 20:80 and 0:100 respectively. The CCN activity of NAFA was found to be represented by a κ value of 0.028. The CCN activities of the mixed particles were overestimated by volume weighted addition of the κ values of the pure compounds, which indicates that synergistic effects of the mixtures tend to lower the CCN activity. Parameterizations of water activity (aw) and surface tension (σ) versus solute concentration were obtained from measurements on aqueous solutions. The CCN activity was modeled on the basis of the parameterizations of aw and σ using Köhler theory. For the particles containing 50% or more NAFA the model overpredicted the CCN activity compared to observations. Reasonable model results were obtained by assuming a surface tension of pure water.

  3. Environmental impact of exhaust emissions by Arctic shipping.

    Science.gov (United States)

    Schröder, Christian; Reimer, Nils; Jochmann, Peter

    2017-12-01

    Since 2005, a dramatic decline of the Arctic sea-ice extent is observed which results in an increase of shipping activities. Even though this provides commercial and social development opportunities, the resulting environmental impacts need to be investigated and monitored. In order to understand the impact of shipping in arctic areas, the method described in this paper determines the travel time, fuel consumption and resulting exhaust emissions of ships navigating in arctic waters. The investigated case studies are considering ship particulars as well as environmental conditions with special focus on ice scenarios. Travel time, fuel consumption and exhaust gas emission were investigated for three different vessels, using different passages of the Northern Sea Route (NSR) in different seasons of years 1960, 2000 and 2040. The presented results show the sensitivity of vessel performance and amount of exhaust emissions to optimize arctic traffic with respect to efficiency, safety and environmental impact.

  4. Effect Effects of Auricularia auricula Polysaccharides on Exhaustive ...

    African Journals Online (AJOL)

    results suggest that AAPs have anti-fatigue activity and could enhance exercise endurance. Effect of AAPs on serum, muscle, and liver. MDA levels. Similar to the effect on performance in the exhaustive swimming test, AAPs also exerted a significant effect on MDA levels as demonstrated in Fig. 2. Serum MDA levels of mice ...

  5. Self-reported Exhaustion is Associated with Small Life Space in Older Adults with Mild Cognitive Impairment

    OpenAIRE

    Tsutsumimoto, Kota; Doi, Takehiko; Shimada, Hiroyuki; Makizako, Hyuma; Uemura, Kazuki; Ando, Hiroshi; Suzuki, Takao

    2014-01-01

    [Purpose] Older adults experience exhaustion-induced health problems, such as poor physical function and low physical activity levels. The associations between self-reported exhaustion and physical function and activity are not clear in older adults with mild cognitive impairment (MCI). The aim of this study was to investigate the relationships between self-reported exhaustion and physical function and activity in older adults with mild cognitive impairment. [Subjects] A total of 356 older ad...

  6. Glass shards, pumice fragments and volcanic aerosol particles - diagenesis a recorder of volcanic activity?

    Science.gov (United States)

    Obenholzner, J. H.; Schroettner, H.; Poelt, P.; Delgado, H.

    2003-04-01

    Detailed SEM/EDS studies of Triassic (Southern Alps, A, I, Sl) and Miocene (Mixteca Alta, Mexico) tuffs revealed that volcanic glass shards can be replaced by zeolites (analcite), chlorites and smectites preserving the shape of primary shards (1). The Triassic pyroclastic deposits have been incorporated in the pre-Alpine burial diagenesis, the Miocene pyroclastic deposits are bentonites. The volcanologist is impressed by the circumstances that million years old pyroclast relict textures can be sized. Shape parameters obtained by image analysis can be compared with much younger pyroclastic deposits (2). Both deposits have not been effected by shearing. The alteration of pumice fragments of Triassic age is not a simple replacement process. Intergrowth of different illites and chlorites and probably vesicle filling by SiO2 and subsequent overgrowth make a reconstruction sometimes difficult. These processes are accompanied by the formation of REE-, Y- and Zr-bearing minerals as well as with the alteration of zircons. Studies of recently erupted ash from Popocatepetl volcano reveal the presence of a variety of µm-sized contact-metamorphosed clasts being a part of the volcanic ash (3). Such clasts should be present in many older pyroclastic deposits, especially where volcanoes had been situated on massive sedimentary units providing contact metamorphism in the realm of a magma chamber or during magma ascent. Volcanic aerosol particles collected in 1997 from the passively degassing plume of Popocatepetl volcano revealed in FESEM/EDS analysis (H. Schroettner and P. Poelt) a wide spectrum of fluffy, spherical and coagulated spherical particles (µm-sized). Under pre-vacuum conditions they remained stable for ca. 3 years (3). In nature the fate of these particles in the atmosphere is unknown. Are there relicts in marine, lacustrine sediments and ice cores, which could be used as proxies of volcanic activity? (1) Obenholzner &Heiken,1999. Ann.Naturhist.Mus.Wien, 100 A, 13

  7. Plant Virus Particles Carrying Tumour Antigen Activate TLR7 and Induce High Levels of Protective Antibody

    Science.gov (United States)

    Jobsri, Jantipa; Allen, Alex; Rajagopal, Deepa; Shipton, Michael; Kanyuka, Kostya; Lomonossoff, George P.; Ottensmeier, Christian; Diebold, Sandra S.; Stevenson, Freda K.; Savelyeva, Natalia

    2015-01-01

    Induction of potent antibody is the goal of many vaccines targeted against infections or cancer. Modern vaccine designs that use virus-like particles (VLP) have shown efficacy for prophylactic vaccination against virus-associated cancer in the clinic. Here we used plant viral particles (PVP), which are structurally analogous to VLP, coupled to a weak idiotypic (Id) tumour antigen, as a conjugate vaccine to induce antibody against a murine B-cell malignancy. The Id-PVP vaccine incorporates a natural adjuvant, the viral ssRNA, which acts via TLR7. It induced potent protective anti-Id antibody responses in an in vivo mouse model, superior to the “gold standard” Id vaccine, with prevalence of the IgG2a isotype. Combination with alum further increased antibody levels and maintained the IgG2a bias. Engagement of TLR7 in vivo was followed by secretion of IFN-α by plasmacytoid dendritic cells and by activation of splenic CD11chi conventional dendritic cells. The latter was apparent from up-regulation of co-stimulatory molecules and from secretion of a wide range of inflammatory cytokines and chemokines including the Th1-governing cytokine IL-12, in keeping with the IgG2a antibody isotype distribution. PVP conjugates are a novel cancer vaccine design, offering an attractive molecular form, similar to VLP, and providing T-cell help. In contrast to VLP, they also incorporate a safe “in-built” ssRNA adjuvant. PMID:25692288

  8. Monitoring the active conformation of green fluorescent protein (GFP) and β-glucosidase adsorbed on soil particles.

    Science.gov (United States)

    Morales-Belpaire, Isabel; Gerin, Patrick A

    2012-01-01

    In order to determine the effect of various soil components on the activity of proteins, we monitored the fluorescence and the enzymatic activity of, respectively, green fluorescent protein (GFP) and β-glucosidase adsorbed on fine soil particles. We also monitored the activity of these proteins in the presence of components that are representative of soil colloids: a montmorillonite clay, goethite and organic matter extracted from soil. Upon adsorption on clay and goethite, GFP lost its fluorescence properties while β-glucosidase suffered only a partial loss of its catalytic activity. Extractable organic matter had an inactivating role on GFP while it did not cause inactivation of β-glucosidase. When GFP and β-glucosidase adsorbed on particles from natural soil samples, their behaviour was consistent with the behaviour observed for these proteins in the presence of the separate components, suggesting that the macroscopic activity of proteins adsorbed on soil particles corresponds to an average of the activities of proteins adsorbed on a mixture of surfaces. The monitoring of the proteins on soil particles with different organic matter contents has also shown that organic matter can have different effects (protecting or inactivating) on different proteins.

  9. Influence of Activated Carbon Particles on Intermetallic Compound Growth Mechanism in Sn-Cu-Ni Composite Solder

    Directory of Open Access Journals (Sweden)

    Ramli M.I.I.

    2016-01-01

    Full Text Available The influence of Activated Carbon (AC particles on mechanical properties of Sn-Cu-Ni-xAC solder joint was investigated. Five different Activated Carbon (AC percentage addition (0 wt. %, 0.25 wt. %, 0.5 wt. %, 0.75 wt. %, and 1.0 wt. % were prepared via powder metallurgy (PM technique. Interfacial IMC thickness measurement and shear strength results showed that with thinner IMC layer (by increasing amount of wt.% of AC, the higher the shear strength of the joint. It is believed that the AC particles suppresses the interfacial IMC growth and thus improves the shear strength.

  10. Effects of decreasing activated carbon particle diameter from 30 μm to 140 nm on equilibrium adsorption capacity.

    Science.gov (United States)

    Pan, Long; Nishimura, Yuki; Takaesu, Hideki; Matsui, Yoshihiko; Matsushita, Taku; Shirasaki, Nobutaka

    2017-11-01

    The capacity of activated carbon particles with median diameters (D50s) of >∼1 μm for adsorption of hydrophobic micropollutants such as 2-methylisolborneol (MIB) increases with decreasing particle size because the pollutants are adsorbed mostly on the exterior (shell) of the particles owing to the limited diffusion penetration depth. However, particles with D50s of adsorption capacities for MIB and several other environmentally relevant adsorbates. The adsorption capacities for low-molecular-weight adsorbates, including MIB, deceased with decreasing particle size for D50s of less than a few micrometers, whereas adsorption capacities increased with decreasing particle size for larger particles. The oxygen content of the particles increased substantially with decreasing particle size for D50s of less than a few micrometers, and oxygen content was negatively correlated with adsorption capacity. The decrease in adsorption capacity with decreasing particle size for the smaller particles was due to particle oxidation during the micromilling procedure used to decrease D50 to ∼140 nm. When oxidation was partially inhibited, the MIB adsorption capacity decrease was attenuated. For high-molecular-weight adsorbates, adsorption capacity increased with decreasing particle size over the entire range of tested particle sizes, even though particle oxygen content increased with decreasing particle size. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. In vitro immunotoxic and genotoxic activities of particles emitted from two different small-scale wood combustion appliances

    Science.gov (United States)

    Tapanainen, Maija; Jalava, Pasi I.; Mäki-Paakkanen, Jorma; Hakulinen, Pasi; Happo, Mikko S.; Lamberg, Heikki; Ruusunen, Jarno; Tissari, Jarkko; Nuutinen, Kati; Yli-Pirilä, Pasi; Hillamo, Risto; Salonen, Raimo O.; Jokiniemi, Jorma; Hirvonen, Maija-Riitta

    2011-12-01

    Residential wood combustion appliances emit large quantities of fine particles which are suspected to cause a substantial health burden worldwide. Wood combustion particles contain several potential health-damaging metals and carbon compounds such as polycyclic aromatic hydrocarbons (PAH), which may determine the toxic properties of the emitted particles. The aim of the present study was to characterize in vitro immunotoxicological and chemical properties of PM 1 ( Dp ≤ 1 μm) emitted from a pellet boiler and a conventional masonry heater. Mouse RAW264.7 macrophages were exposed for 24 h to different doses of the emission particles. Cytotoxicity, production of the proinflammatory cytokine TNF-α and the chemokine MIP-2, apoptosis and phases of the cell cycle as well as genotoxic activity were measured after the exposure. The type of wood combustion appliance had a significant effect on emissions and chemical composition of the particles. All the studied PM 1 samples induced cytotoxic, genotoxic and inflammatory responses in a dose-dependent manner. The particles emitted from the conventional masonry heater were 3-fold more potent inducers of programmed cell death and DNA damage than those emitted from the pellet boiler. Furthermore, the particulate samples that induced extensive DNA damage contained also large amounts of PAH compounds. Instead, significant differences between the studied appliances were not detected in measurements of inflammatory mediators, although the chemical composition of the combustion particles differed considerably from each other. In conclusion, the present results show that appliances representing different combustion technology have remarkable effects on physicochemical and associated toxicological and properties of wood combustion particles. The present data indicate that the particles emitted from incomplete combustion are toxicologically more potent than those emitted from more complete combustion processes.

  12. T Cell Exhaustion During Persistent Viral Infections

    Science.gov (United States)

    Kahan, Shannon M.; Wherry, E. John; Zajac, Allan J.

    2015-01-01

    Although robust and highly effective anti-viral T cells contribute to the clearance of many acute infections, viral persistence is associated with the development of functionally inferior, exhausted, T cell responses. Exhaustion develops in a step-wise and progressive manner, ranges in severity, and can culminate in the deletion of the anti-viral T cells. This disarming of the response is consequential as it compromises viral control and potentially serves to dampen immune-mediated damage. Exhausted T cells are unable to elaborate typical anti-viral effector functions. They are characterized by the sustained upregulation of inhibitory receptors and display a gene expression profile that distinguishes them from prototypic effector and memory T cell populations. In this review we discuss the properties of exhausted T cells; the virological and immunological conditions that favor their development; the cellular and molecular signals that sustain the exhausted state; and strategies for preventing and reversing exhaustion to favor viral control. PMID:25620767

  13. The active surface of suspended particles as a predictor of lung function and pulmonary symptoms in Austrian school children

    Science.gov (United States)

    Moshammer, Hanns; Neuberger, Manfred

    At a central elementary school in the capital of Upper Austria children aged 7-10 years underwent repeated respiratory health checkups (questionnaires, diaries, spirometry). Between March and May 2001 the daily means of the signals of a diffusion charging sensor, measuring the "active surface" of suspended particles, and a photoelectric aerosol sensor, measuring the particle-bound polycyclic aromatic hydrocarbons, were related to spirometric results of the total 164 children examined and to the daily symptom scores of a susceptible subgroup. Significant reductions of forced vital capacity ( p=0.006) and forced expiratory volume in the first second ( p=0.001) and significant increases of wheezing ( p=0.001), shortness of breath ( p=0.041), cough in the evening ( p=0.031) and at night ( p=0.018) were found with increase of "active surface" of suspended particles measured at the adjacent outdoor monitoring station, but not with the increase of particle-bound polycyclic aromatic hydrocarbons. Monitoring "active surface" of particles with diameters of about 10 nm-1 μm by means of a diffusion charging sensor might provide additional information in surveillance of particulate matter for prevention of acute effects on respiratory health.

  14. Toxicological properties of nanoparticles of organic compounds (NOC) from flames and vehicle exhausts.

    Science.gov (United States)

    Sgro, L A; Simonelli, A; Pascarella, L; Minutolo, P; Guarnieri, D; Sannolo, N; Netti, P; D'Anna, A

    2009-04-01

    We examined the biological reactivity in vitro of nanoparticles of organic compounds (NOC) with diameters, d = 1-3 nm, a class of combustion-generated particulate relatively unstudied compared to larger more graphitic soot particles because of their small size even though they may contribute significantly to the organic fraction of PM sampled from vehicle exhausts and urban atmospheres. We tested NOC samples collected from 2004 model vehicle emissions and laboratory flames. NOC produced a dose dependent mutagenic response in Salmonella bacteria, suggesting that NOC may add significantly to the overall mutagenicity of vehicle emissions. Incubation with peptides caused agglomeration and precipitate of the otherwise stable NOC suspension, but the chemical and/or physical nature of the NOC-peptide interactions could not be resolved. A significant cytotoxic response was measured above a critical dose of NOC in mouse embryo fibroblasts NIH3T3 cells along with possible evidence of cellular uptake by optical and confocal microscopy. The toxicological assays showed that NOC collected from flames and vehicle exhausts effectively interacted in vitro with both prokaryotic and eukaryotic cells. Differences in mutagenic potencies observed for various Salmonella strains with and without metabolic activation indicate differences in the chemical composition of NOC collected from different vehicles and flames.

  15. Desulphurization of exhaust gases in chemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, K.; Wischnewski, W.

    1981-01-01

    The sulfur content of exhaust gases can be reduced by: desulphurization of fuels; modification of processes; or treatment of resultant gases. In this paper a few selected examples from the chemical industry in the German Democratic Republic are presented. Using modified processes and treating the resultant gases, the sulphuric content of exhaust gases is effectively reduced. Methods to reduce the sulfur content of exhaust gases are described in the field of production of: sulphuric acid; viscose; fertilizers; and paraffin.

  16. Emotionally exhausting factors in general practitioners? work

    OpenAIRE

    Torppa, M.A.; Kuikka, L.; Nevalainen, M.; Pitk?l?, K.H.

    2015-01-01

    Background. Emotional exhaustion is central in burnout syndrome and signals its development. General practitioners? (GP) work is emotionally challenging but research on these aspects is lacking. Objective. To study the prevalence of emotional exhaustion among GPs and to evaluate how their characteristics and work experiences are associated with emotional exhaustion. Design and methods. A questionnaire survey was carried out among GPs in Finland in 2011 in which questions were posed regarding ...

  17. Particulate matters from diesel engine exhaust emission

    Directory of Open Access Journals (Sweden)

    Petrović Velimir S.

    2008-01-01

    Full Text Available Air pollution caused by diesel engine emissions, especially particulate matters and nitric oxides emissions, is one of the biggest problems of current transportation. In the near future the emission of diesel particulate matters will become one of the most important factors that will affect the trend of engine development. Ambient airborne particles have adverse environmental and health effects and therefore their concentration in the air is regulated. Recent medical studies showed that different particle properties are important (for example: number/concentration, active surface, chemical composition/morphology and may take role in the responsibility for their human health impact. Thus, diesel engines are one of the most important sources of particles in the atmosphere, especially in urban areas. Studying health effects and diesel engine particulate properties, it has been concluded that they are a complex mixture of solids and liquids. Biological activity of particulate matter may be related to particle sizes and their number. The paper presents the activities of UN-ECE working group PMP on defining the best procedure and methodology for the measurement of passenger cars diesel engines particle mass and number concentrations. The results of inter-laboratory emissions testing are presented for different engine technologies with special attention on repeatability and reproducibility of measured data. .

  18. Leadership, organizational stress, and emotional exhaustion among hospital nursing staff.

    Science.gov (United States)

    Stordeur, S; D'hoore, W; Vandenberghe, C

    2001-08-01

    STUDY'S RATIONALE AND OBJECTIVES: We examined the effect of work stressors and head nurses' transactional and transformational leadership on the levels of emotional exhaustion experienced among their staff. A questionnaire was sent to all nurses of a university hospital. Usable returns were received from 625 nurses, giving a response rate of 39.2%. Data were treated using correlational analyses and multiple regression. The latter modelled stressors and leadership as predictors of nurses' reported emotional exhaustion. Work stressors were assessed using the Nursing Stress Scale (NSS) which comprises 34 items divided into three subscales (referring to stress from the physical, psychological, and social environment), and the role ambiguity (three items) and conflict (three items) scales. Leadership was measured with the Multifactor Leadership Questionnaire. In regression analyses, work stressors as a whole were found to explain 22% of the variance in emotional exhaustion whereas leadership dimensions explained 9% of the variance in that outcome measure. Stress emanating from the physical and social environment, role ambiguity, and active management-by-exception leadership were significantly associated with increased levels of emotional exhaustion. Transformational and contingent reward leadership did not influence emotional exhaustion. A limitation of this study is that it considered only the emotional exhaustion dimension of burnout. Also, as data were cross-sectional in nature, conclusions regarding the direction of causality among variables cannot be drawn. This study provided, for the first time, a test of the influence of leadership on burnout among nurses, taking into account the role of work stressors. Future research is needed to examine if the effects reported herein can be replicated using the two other dimensions of burnout (depersonalization and reduced personal accomplishment).

  19. Production in yeast of pseudotype virus-like particles harboring functionally active antibody fragments neutralizing the cytolytic activity of vaginolysin

    Directory of Open Access Journals (Sweden)

    Pleckaityte Milda

    2011-12-01

    Full Text Available Abstract Background Recombinant antibodies can be produced in different formats and different expression systems. Single chain variable fragments (scFvs represent an attractive alternative to full-length antibodies and they can be easily produced in bacteria or yeast. However, the scFvs exhibit monovalent antigen-binding properties and short serum half-lives. The stability and avidity of the scFvs can be improved by their multimerization or fusion with IgG Fc domain. The aim of the current study was to investigate the possibilities to produce in yeast high-affinity scFv-Fc proteins neutralizing the cytolytic activity of vaginolysin (VLY, the main virulence factor of Gardnerella vaginalis. Results The scFv protein derived from hybridoma cell line producing high-affinity neutralizing antibodies against VLY was fused with human IgG1 Fc domain. Four different variants of anti-VLY scFv-Fc fusion proteins were constructed and produced in yeast Saccharomyces cerevisiae. The non-tagged scFv-Fc and hexahistidine-tagged scFv-Fc proteins were found predominantly as insoluble aggregates and therefore were not suitable for further purification and activity testing. The addition of yeast α-factor signal sequence did not support secretion of anti-VLY scFv-Fc but increased the amount of its intracellular soluble form. However, the purified protein showed a weak VLY-neutralizing capability. In contrast, the fusion of anti-VLY scFv-Fc molecules with hamster polyomavirus-derived VP2 protein and its co-expression with VP1 protein resulted in an effective production of pseudotype virus-like particles (VLPs that exhibited strong VLY-binding activity. Recombinant scFv-Fc molecules displayed on the surface of VLPs neutralized VLY-mediated lysis of human erythrocytes and HeLa cells with high potency comparable to that of full-length antibody. Conclusions Recombinant scFv-Fc proteins were expressed in yeast with low efficiency. New approach to display the sc

  20. Exhaust gas bypass valve control for thermoelectric generator

    Science.gov (United States)

    Reynolds, Michael G; Yang, Jihui; Meisner, Greogry P.; Stabler, Francis R.; De Bock, Hendrik Pieter Jacobus; Anderson, Todd Alan

    2012-09-04

    A method of controlling engine exhaust flow through at least one of an exhaust bypass and a thermoelectric device via a bypass valve is provided. The method includes: determining a mass flow of exhaust exiting an engine; determining a desired exhaust pressure based on the mass flow of exhaust; comparing the desired exhaust pressure to a determined exhaust pressure; and determining a bypass valve control value based on the comparing, wherein the bypass valve control value is used to control the bypass valve.

  1. T cell exhaustion and immune-mediated disease-the potential for therapeutic exhaustion.

    Science.gov (United States)

    McKinney, Eoin F; Smith, Kenneth Gc

    2016-12-01

    T cell exhaustion represents a continuous spectrum of cellular dysfunction induced during chronic viral infection, facilitating viral persistence and associating with poor clinical outcome. Modulation of T cell exhaustion can restore function in exhausted CD8 T cells, promoting viral clearance. Exhaustion has also been implicated as playing an important role in anti-tumour responses, whereby exhausted tumour-infiltrating lymphocytes fail to control tumour progression. More recently exhaustion has been linked to long-term clinical outcome in multiple autoimmune diseases but, in contrast to cancer or infection, it is associated with a favourable clinical outcome characterised by fewer relapses. An increasing understanding of key inhibitory signals promoting exhaustion has led to advances in therapy for chronic infection and cancer. An increasing understanding of this biology may facilitate novel treatment approaches for autoimmunity through the therapeutic induction of exhaustion. Copyright © 2016. Published by Elsevier Ltd.

  2. Bactericidal activity of green tea extracts: the importance of catechin containing nano particles.

    Science.gov (United States)

    Gopal, Judy; Muthu, Manikandan; Paul, Diby; Kim, Doo-Hwan; Chun, Sechul

    2016-01-28

    When we drink green tea infusion, we believe we are drinking the extract of the green tea leaves. While practically each tea bag infused in 300 mL water contains about 50 mg of suspended green tea leaf particles. What is the role of these particles in the green tea effect is the objective of this study. These particles (three different size ranges) were isolated via varying speed centrifugation and their respective inputs evaluated. Live oral bacterial samples from human volunteers have been screened against green tea extracts and macro, micro and nano sized green tea particles. The results showed that the presence/absence of the macro and mico sized tea particles in the green tea extract did not contribute much. However, the nano sized particles were characterized to be nature's nano stores of the bioactive catechins. Eradication of these nano tea particles resulted in decrease in the bactericidal property of the green tea extracts. This is a curtain raiser investigation, busting the nano as well as green tea leaf particle contribution in green tea extracts.

  3. Structure of PS/PMMA Blends with Interfacially Active Janus Particles Derived from ABC Triblock Copolymers

    Science.gov (United States)

    Bryson, Kyle; Löbling, Tina; Müller, Axel; Hayward, Ryan; Russell, Thomas

    2014-03-01

    Kinetic trapping of bicontinuous polymer morphologies on submicron length scales through the interfacial adsorption of nanoparticles is of interest due to the unique combination of the properties of each component provided by such structures, and their potential for use as membranes and composite materials. However, this strategy is challenging to realize in polymeric systems, due to the difficulties in preparing particles that are neutrally wetted by the two polymer phases. Janus particles afford a route to circumvent the necessity of neutral wettability. Both theory and experiment have shown enhanced interfacial adsorption energies for Janus particles, as well as greater flexibility in controlling particle orientation at the interface, in comparison to homogeneous particles. Janus particles with polystyrene and poly(methyl methacrylate) (PS/PMMA) hemispheres and a crosslinked polybutadiene core were prepared from triblock copolymers. Using blends of PS and PMMA homopolymers and the Janus particles, we examined structures produced by phase separation during solvent casting and thermodynamic demixing transitions via TEM and small-angle light scattering. The results elucidate the role of particle wettability on interfacial behavior and the structure of stabilized emulsions.

  4. Real-time observation of signal recognition particle binding to actively translating ribosomes

    Science.gov (United States)

    Noriega, Thomas R; Chen, Jin; Walter, Peter; Puglisi, Joseph D

    2014-01-01

    The signal recognition particle (SRP) directs translating ribosome-nascent chain complexes (RNCs) that display a signal sequence to protein translocation channels in target membranes. All previous work on the initial step of the targeting reaction, when SRP binds to RNCs, used stalled and non-translating RNCs. This meant that an important dimension of the co-translational process remained unstudied. We apply single-molecule fluorescence measurements to observe directly and in real-time E. coli SRP binding to actively translating RNCs. We show at physiologically relevant SRP concentrations that SRP-RNC association and dissociation rates depend on nascent chain length and the exposure of a functional signal sequence outside the ribosome. Our results resolve a long-standing question: how can a limited, sub-stoichiometric pool of cellular SRP effectively distinguish RNCs displaying a signal sequence from those that are not? The answer is strikingly simple: as originally proposed, SRP only stably engages translating RNCs exposing a functional signal sequence. DOI: http://dx.doi.org/10.7554/eLife.04418.001 PMID:25358118

  5. Noise characteristics of stacked CMOS active pixel sensor for charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Kunihiro, Takuya E-mail: kunihiro@geo.titech.ac.jp; Nagashima, Kazuhide; Takayanagi, Isao; Nakamura, Junichi; Kosaka, Koji; Yurimoto, Hisayoshi

    2001-09-11

    The noise characteristics of a stacked CMOS active pixel sensor (SCAPS) for incident charged particles have been analyzed under 4.5 keV Si{sup +} ion irradiation. The source of SCAPS dark current was found to change from thermal to electron leakage with decreasing device temperature. Leakage current at charge integration part in a pixel has been reduced to 0.1 electrons s{sup -1} at 77 K. The incident ion signals are computed by subtracting reset frame values from each frame using a non-destructive readout operation. With increase of irradiated ions, the dominant noise source changed from read noise, and shot noise from the incident ions, to signal frame fixed-pattern noise from variations in sensitivity between pixels. Pixel read noise is equivalent to ten incident ions. The charge of an incident ion is converted to 1.5 electrons in the pixel capacitor. Shot noise corresponds to the statistical fluctuation of incident ions. Signal frame fixed-pattern noise is 0.7% of the signal. By comparing full well conditions to noise floor, a dynamic range of 80 dB is achieved. SCPAS is useful as a two-dimensional detector for microanalyses such as stigmatic secondary ion mass spectrometry.

  6. The topography of the environment alters the optimal search strategy for active particles

    Science.gov (United States)

    Volpe, Giorgio; Volpe, Giovanni

    2017-10-01

    In environments with scarce resources, adopting the right search strategy can make the difference between succeeding and failing, even between life and death. At different scales, this applies to molecular encounters in the cell cytoplasm, to animals looking for food or mates in natural landscapes, to rescuers during search and rescue operations in disaster zones, and to genetic computer algorithms exploring parameter spaces. When looking for sparse targets in a homogeneous environment, a combination of ballistic and diffusive steps is considered optimal; in particular, more ballistic Lévy flights with exponent α≤1 are generally believed to optimize the search process. However, most search spaces present complex topographies. What is the best search strategy in these more realistic scenarios? Here, we show that the topography of the environment significantly alters the optimal search strategy toward less ballistic and more Brownian strategies. We consider an active particle performing a blind cruise search for nonregenerating sparse targets in a 2D space with steps drawn from a Lévy distribution with the exponent varying from α=1 to α=2 (Brownian). We show that, when boundaries, barriers, and obstacles are present, the optimal search strategy depends on the topography of the environment, with α assuming intermediate values in the whole range under consideration. We interpret these findings using simple scaling arguments and discuss their robustness to varying searcher's size. Our results are relevant for search problems at different length scales from animal and human foraging to microswimmers' taxis to biochemical rates of reaction.

  7. Particle Filter with Integrated Voice Activity Detection for Acoustic Source Tracking

    Directory of Open Access Journals (Sweden)

    Lehmann Eric A

    2007-01-01

    Full Text Available In noisy and reverberant environments, the problem of acoustic source localisation and tracking (ASLT using an array of microphones presents a number of challenging difficulties. One of the main issues when considering real-world situations involving human speakers is the temporally discontinuous nature of speech signals: the presence of silence gaps in the speech can easily misguide the tracking algorithm, even in practical environments with low to moderate noise and reverberation levels. A natural extension of currently available sound source tracking algorithms is the integration of a voice activity detection (VAD scheme. We describe a new ASLT algorithm based on a particle filtering (PF approach, where VAD measurements are fused within the statistical framework of the PF implementation. Tracking accuracy results for the proposed method is presented on the basis of synthetic audio samples generated with the image method, whereas performance results obtained with a real-time implementation of the algorithm, and using real audio data recorded in a reverberant room, are published elsewhere. Compared to a previously proposed PF algorithm, the experimental results demonstrate the improved robustness of the method described in this work when tracking sources emitting real-world speech signals, which typically involve significant silence gaps between utterances.

  8. Comparison of lighting activity and inner radiation belt particle fluxes perturbations

    Science.gov (United States)

    Martinez Calderon, C.; Bortnik, J.; Li, W.; Spence, H. E.; Rodger, C. J.

    2016-12-01

    Lightning discharges are known to inject whistlers into the inner magnetosphere over a wide range of latitudes around their source. When a discharge occurs, it radiates electromagnetic energy, some of which propagates in the whistler-mode wave through the ionospheric plasma travelling away from the Earth. Previous studies have discussed the effects of whistler-induced electron precipitation and radiation belt losses associated with lightning but there has been little research on the long term effects of these precipitation on the inner radiation belts [Rodger et al. (2004), Clilverd et al. (2004)].Here, we use data from the World Wide Lightning Location Network (WWLLN), which has continuously monitored global lightning since 2004, to examine one year of lightning data and locate the L-shells with high lighting activity. We use Van Allen Probes' Energetic Particle, Composition, and Thermal Plasma Suite (ECT) from both satellites (RBSP-A/B) to measure electron fluxes in the inner radiation belt at the L-shells of interest. We compare these fluxes to a globally-integrated count of lightning strikes and investigate the relationship between global lightning occurrence and RBSP electron fluxes. We examine several factors, such as different energy ranges, timescales ranging from a few weeks to the entire year and seasonal changes in order to quantify the loss process driven by lightning in the inner radiation belts.

  9. Design and testing of monolithic active pixel sensors for charged particle tracking

    CERN Document Server

    Deptuch, G; Claus, G; Colledani, C; Dulinski, W; Gornushkin, Y; Husson, D; Riester, J L; Winter, M

    2002-01-01

    A monolithic active pixel sensor (MAPS) for charged particle tracking based on a novel detector structure has been proposed, simulated, fabricated and tested. This detector is inseparable from the readout electronics, since both of them are integrated on the same, low- resistivity silicon wafer standard for a CMOS process. The individual pixel is comprised of only three MOS transistors and a photodiode collecting the charge created in the thin undepleted epitaxial layer. This approach provides a low cost, high resolution and thin device with the whole detector area sensitive to radiation (100% fill factor). Detailed device simulations using the ISE-TCAD package have been carried out in order to study the charge. collection mechanism and to validate the proposed idea. In order to demonstrate viability of the technique, two prototype chips were successively fabricated using 0.6 mu m and 0.35 mu m CMOS processes. Both chips have been fully characterized. The pixel conversion gain has been calibrated using a /sup...

  10. The Role of HO(x) in Super- and Subsonic Aircraft Exhaust Plumes

    Science.gov (United States)

    Hanisco, T. F.; Wennberg, P. O.; Cohen, R. C.; Anderson, J. G.; Fahey, D. W.; Keim, E. R.; Gao, R. S.; Wamsley, R. C.; Donnelly, S. G.; DelNegro, L. A.; hide

    1997-01-01

    The generation of sulfuric acid aerosols in aircraft exhaust has emerged as a critical issue in determining the impact of supersonic aircraft on stratospheric ozone. It has long been held that the first step in the mechanism of aerosol formation is the oxidation of SO2 emitted from the engine by OH in the exhaust plume. We report in situ measurements of OH and HO2 in the exhaust plumes of a supersonic (Air France Concorde) and a subsonic (NASA ER-2) aircraft in the lower stratosphere. These measurements imply that reactions with OH are responsible for oxidizing only a small fraction of SO2 (2%), and thus cannot explain the large number of particles observed in the exhaust wake of the Concorde.

  11. The role of HOx in super- and subsonic aircraft exhaust plumes

    Science.gov (United States)

    Hanisco, T. F.; Wennberg, P. O.; Cohen, R. C.; Anderson, J. G.; Fahey, D. W.; Keim, E. R.; Gao, R. S.; Wamsley, R. C.; Donnelly, S. G.; Del Negro, L. A.; Salawitch, R. J.; Kelly, K. K.; Proffitt, M. H.

    The generation of sulfuric acid aerosols in aircraft exhaust has emerged as a critical issue in determining the impact of supersonic aircraft on stratospheric ozone. It has long been held that the first step in the mechanism of aerosol formation is the oxidation of SO2 emitted from the engine by OH in the exhaust plume. We report in situ measurements of OH and HO2 in the exhaust plumes of a supersonic (Air France Concorde) and a subsonic (NASA ER-2) aircraft in the lower stratosphere. These measurements imply that reactions with OH are responsible for oxidizing only a small fraction of SO2 (2%), and thus cannot explain the large number of particles observed in the exhaust wake of the Concorde.

  12. Particle size dependence on oxygen reduction reaction activity of electrodeposited TaOx catalysts in acidic media

    KAUST Repository

    Seo, J.

    2013-11-13

    The size dependence of the oxygen reduction reaction activity was studied for TaOx nanoparticles electrodeposited on carbon black for application to polymer electrolyte fuel cells (PEFCs). Compared with a commercial Ta2O5 material, the ultrafine oxide nanoparticles exhibited a distinctively high onset potential different from that of the bulky oxide particles.

  13. Assessment of the associated particle prompt gamma neutron activation technique for total body nitrogen measurement in vivo

    Science.gov (United States)

    Total Body Nitrogen (TBN) can be used to estimate Total Body Protein (TBP), an important body composition component at the molecular level. A system using the associated particle technique in conjunction with prompt gamma neutron activation analysis has been developed for the measurement of TBN in ...

  14. Interactions of benzo[a]pyrene and diesel exhaust particulate matter with the lung surfactant system.

    Science.gov (United States)

    Sosnowski, Tomasz R; Koliński, Michal; Gradón, Leon

    2011-04-01

    One of the reasons for cellular changes in the lung tissue exposed to the diesel exhaust composed of soot particles with adsorbed volatile organic molecules is the reduction of the clearance rate in the pulmonary region of the respiratory system. The interaction of the fractal-like particles and organic substances with a surfactant monolayer limits its dynamic activity. The surface properties of Survanta, a purified extract of bovine lung surfactant (LS), which interacted with carbon particles (200 nm aggregates) and benzo[a]pyrene (BaP), molecules were measured with the oscillating bubble technique. The results showed a significant lowering of the dynamics of the surfactant monolayer compared to the control case (no exposure). Additional measurements of surface pressure during the monotonic compression of the air-water interface containing the major LS phospholipid, dipalmitoylphosphatidylcholine (DPPC), showed that the presence of BaP molecules in the system influenced its stability. The experimental results were supplemented with a theoretical molecular dynamics model of the interaction between BaP and DPPC molecules. The simulation results indicated the insertion of BaP molecules into the lipid layer, which explained the measured effects.

  15. LARGE SOLAR ENERGETIC PARTICLE EVENTS ASSOCIATED WITH FILAMENT ERUPTIONS OUTSIDE ACTIVE REGIONS

    Energy Technology Data Exchange (ETDEWEB)

    Gopalswamy, N.; Mäkelä, P.; Akiyama, S.; Yashiro, S.; Xie, H.; Thakur, N. [Solar Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kahler, S. W., E-mail: nat.gopalswamy@nasa.gov [Air Force Research Laboratory, Albuquerque, NM 87117 (United States)

    2015-06-10

    We report on four large filament eruptions (FEs) from solar cycles 23 and 24 that were associated with large solar energetic particle (SEP) events and interplanetary type II radio bursts. The post-eruption arcades corresponded mostly to C-class soft X-ray enhancements, but an M1.0 flare was associated with one event. However, the associated coronal mass ejections (CMEs) were fast (speeds ∼ 1000 km s{sup −1}) and appeared as halo CMEs in the coronagraph field of view. The interplanetary type II radio bursts occurred over a wide wavelength range, indicating the existence of strong shocks throughout the inner heliosphere. No metric type II bursts were present in three events, indicating that the shocks formed beyond 2–3 Rs. In one case, there was a metric type II burst with low starting frequency, indicating a shock formation height of ∼2 Rs. The FE-associated SEP events did have softer spectra (spectral index >4) in the 10–100 MeV range, but there were other low-intensity SEP events with spectral indices ≥4. Some of these events are likely FE-SEP events, but were not classified as such in the literature because they occurred close to active regions. Some were definitely associated with large active region flares, but the shock formation height was large. We definitely find a diminished role for flares and complex type III burst durations in these large SEP events. Fast CMEs and shock formation at larger distances from the Sun seem to be the primary characteristics of the FE-associated SEP events.

  16. Investigation of Plasma Exhaust Profile Manipulation Using Magnetic Fields

    Science.gov (United States)

    Shambaugh, Bryan A.

    Electric propulsion systems are known for having a high specific impulse but very low thrust. In the case of a hypersonic, compressible flow, altering the exhaust profile has the potential to alter the exhaust velocity thus changing the total thrust output. In this research, the magnetoplasmadynamic (MPD) effects of applying a toroidal magnetic field to an ionized exhaust plume were investigated to manipulate the exhaust profile of the plasma jet under near vacuum conditions. The project also endeavored to determine the efficacy of permanent magnets as a replacement for electromagnetic systems in rocket propulsion. Tests for this experiment were conducted using the West Virginia University (WVU) Hypersonic Arc Jet Wind Tunnel, in which a series of N52 grade neodymium magnets were placed in different orientations around a steel toroid mounted around the arc jet plume. Four different magnet orientations which produced different magnetic fields around the plume were tested in this experiment: two of the configurations held the magnetic poles aligned with the flow direction with north or south facing the nozzle; two configurations held the magnetic poles in a tangential orientation to the flow with north or south facing in a clockwise direction. All magnets in each of the magnetized cases were positioned equidistant to one another and equidistant to the toroid's central axis. Two additional configurations were run as control tests without any imposed magnetic fields surrounding the plume. Each test was documented using 12 sets of photographs taken from a fixed position with respect to the flow, and the photographic data was analyzed by comparing images of the exhaust plume taken 10, 20, and 30 seconds after the plasma jet was activated. Analysis of the collected images showed that the tangential configurations where the magnets' north poles were oriented clockwise held the most influence in decreasing the size of the exhaust profile across all time steps. In contrast

  17. Modeling Transport in Fractured Porous Media with the Random-Walk Particle Method: The Transient Activity Range and the Particle-Transfer Probability

    Energy Technology Data Exchange (ETDEWEB)

    Lehua Pan; G.S. Bodvarsson

    2001-10-22

    Multiscale features of transport processes in fractured porous media make numerical modeling a difficult task, both in conceptualization and computation. Modeling the mass transfer through the fracture-matrix interface is one of the critical issues in the simulation of transport in a fractured porous medium. Because conventional dual-continuum-based numerical methods are unable to capture the transient features of the diffusion depth into the matrix (unless they assume a passive matrix medium), such methods will overestimate the transport of tracers through the fractures, especially for the cases with large fracture spacing, resulting in artificial early breakthroughs. We have developed a new method for calculating the particle-transfer probability that can capture the transient features of diffusion depth into the matrix within the framework of the dual-continuum random-walk particle method (RWPM) by introducing a new concept of activity range of a particle within the matrix. Unlike the multiple-continuum approach, the new dual-continuum RWPM does not require using additional grid blocks to represent the matrix. It does not assume a passive matrix medium and can be applied to the cases where global water flow exists in both continua. The new method has been verified against analytical solutions for transport in the fracture-matrix systems with various fracture spacing. The calculations of the breakthrough curves of radionuclides from a potential repository to the water table in Yucca Mountain demonstrate the effectiveness of the new method for simulating 3-D, mountain-scale transport in a heterogeneous, fractured porous medium under variably saturated conditions.

  18. Sintered indium-tin oxide particles induce pro-inflammatory responses in vitro, in part through inflammasome activation.

    Directory of Open Access Journals (Sweden)

    Melissa A Badding

    Full Text Available Indium-tin oxide (ITO is used to make transparent conductive coatings for touch-screen and liquid crystal display electronics. As the demand for consumer electronics continues to increase, so does the concern for occupational exposures to particles containing these potentially toxic metal oxides. Indium-containing particles have been shown to be cytotoxic in cultured cells and pro-inflammatory in pulmonary animal models. In humans, pulmonary alveolar proteinosis and fibrotic interstitial lung disease have been observed in ITO facility workers. However, which ITO production materials may be the most toxic to workers and how they initiate pulmonary inflammation remain poorly understood. Here we examined four different particle samples collected from an ITO production facility for their ability to induce pro-inflammatory responses in vitro. Tin oxide, sintered ITO (SITO, and ventilation dust particles activated nuclear factor kappa B (NFκB within 3 h of treatment. However, only SITO induced robust cytokine production (IL-1β, IL-6, TNFα, and IL-8 within 24 h in both RAW 264.7 mouse macrophages and BEAS-2B human bronchial epithelial cells. Our lab and others have previously demonstrated SITO-induced cytotoxicity as well. These findings suggest that SITO particles activate the NLRP3 inflammasome, which has been implicated in several immune-mediated diseases via its ability to induce IL-1β release and cause subsequent cell death. Inflammasome activation by SITO was confirmed, but it required the presence of endotoxin. Further, a phagocytosis assay revealed that pre-uptake of SITO or ventilation dust impaired proper macrophage phagocytosis of E. coli. Our results suggest that adverse inflammatory responses to SITO particles by both macrophage and epithelial cells may initiate and propagate indium lung disease. These findings will provide a better understanding of the molecular mechanisms behind an emerging occupational health issue.

  19. CHANG'E-3 Active Particle-induced X-ray Spectrometer: The synthesis design and performance

    Science.gov (United States)

    Cui, XingZhu; Peng, Wenxi; Wang, Huanyu; Liang, XiaoHua

    the Active Particle X-ray Spectrometer (APXS) was designed to deduce the elemental abundances of samples on the moon. Similar to the Alpha Particle X-ray Spectrometers onboard MSL and MER , the APXS was also an instrument took the advantage of X-ray fluorescence mechanism to determine elemental abundances, it determines the chemical compositions of both soil and rocks along the traverse of the rover. To provide a sound instrument working on the lunar surface,Four components were integrated in the APXS, the performances of the components were described in this paper.

  20. Bactericidal activity of green tea extracts: the importance of catechin containing nano particles

    OpenAIRE

    Judy Gopal; Manikandan Muthu; Diby Paul; Doo-Hwan Kim; Sechul Chun

    2016-01-01

    When we drink green tea infusion, we believe we are drinking the extract of the green tea leaves. While practically each tea bag infused in 300?mL water contains about 50?mg of suspended green tea leaf particles. What is the role of these particles in the green tea effect is the objective of this study. These particles (three different size ranges) were isolated via varying speed centrifugation and their respective inputs evaluated. Live oral bacterial samples from human volunteers have been ...

  1. Local Exhaust Optimization and Worker Exposure

    DEFF Research Database (Denmark)

    Heiselberg, Per; Pedersen, Morten; Plath, Thomas

    This paper describes a process of optimisation of exhaust efficiency and of minimisation of worker exposure at a semiautomatic printing machine at a printing office.......This paper describes a process of optimisation of exhaust efficiency and of minimisation of worker exposure at a semiautomatic printing machine at a printing office....

  2. Vital exhaustion and risk for cancer

    DEFF Research Database (Denmark)

    Bergelt, Corinna; Christensen, Jane Hvarregaard; Prescott, Eva

    2005-01-01

    Vital exhaustion, defined as feelings of depression and fatigue, has previously been investigated mainly as a risk factor for cardiovascular disease. The authors investigated the association between depressive feelings and fatigue as covered by the concept of vital exhaustion and the risk...

  3. 49 CFR 393.83 - Exhaust systems.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Exhaust systems. 393.83 Section 393.83... NECESSARY FOR SAFE OPERATION Miscellaneous Parts and Accessories § 393.83 Exhaust systems. (a) Every motor... shall have a system to direct the discharge of such fumes. No part shall be located where its location...

  4. Effect of exhaustive exercise on myocardial performance.

    Science.gov (United States)

    Grimditch, G K; Barnard, R J; Duncan, H W

    1981-11-01

    Several investigators have reported ultrastructural changes in hearts of animals exercised to exhaustion. The present study was designed to determine whether functional changes occur in the intact heart at exhaustion. Adult mongrel dogs (n = 8) were chronically instrumented to measure cardiac output, coronary blood flow, aortic blood pressure, left ventricular pressure, +dP/dtmax, and -dP/dtmax. After recovery, the dogs were run to exhaustion at a constant work load, eliciting approximately 70% of maximum heart rate. The exhaustive bouts were terminated when the animals either refused or were unable to continue running, at which time their rectal temperatures approaches 42.2 degree C. The mean exhaustion time was 76.7 +/- 11.8 min. All parameters increased from rest to steady state with the exception of stroke volume (23.2 +/- 4.9 vs. 20.5 +/- 1.6 ml), which remained constant. In the transition from steady state to exhaustion, only +dP/dtmax (6,652 +/- 291 vs. 7,689 +/- 479 Torr/s) and -dP/dtmax (4,110 +/- 227 vs. 4,890 +/- 215 Torr/s) increased significantly; all other values exhibited no significant change. Similarly, when maximum cardiovascular parameters were measured before and after exhaustion, no significant changes were found. These data show that cardiac contractile function is not depressed in dogs as a result of exhaustive exercise.

  5. Nitration of benzo[a]pyrene adsorbed on coal fly ash particles by nitrogen dioxide: role of thermal activation.

    Science.gov (United States)

    Kristovich, Robert L; Dutta, Prabir K

    2005-09-15

    Nitration of benzo[a]pyrene (BaP) by nitrogen dioxide (NO2) adsorbed on the surface of thermally activated coal fly ash and model aluminosilicate particles led to the formation of nitrobenzo[a]pyrenes as verified by extraction and gas chromatography/mass spectrometry (GC/MS). In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was utilized to follow the nitration reaction on the surface of zeolite Y. Nitrobenzo[a]pyrene formation was observed along with the formation of nitrous acid and nitrate species. The formation of the BaP radical cation was also observed on thermally activated aluminosilicate particles by electron spin resonance (ESR) spectroscopy. On the basis of GC/MS, DRIFTS, and ESR spectroscopy results, a mechanism of nitration involving intermediate BaP radical cations generated on thermally activated aluminosilicate particles is proposed. These observations have led to the hypothesis that nitration of adsorbed polyaromatic hydrocarbons on coal fly ash by reaction with nitrogen oxides can occur in the smokestack, but with the aging of the fly ash particles, the extent of the nitration reaction will be diminished.

  6. Circulating factors induce coronary endothelial ceIl activation foIlowing exposure to inhaled diesel exhaust and nitrogen dioxide in humans :Evidence from a novel translational in vitro model

    Science.gov (United States)

    The vascular toxicity of inhaled agents may be caused by soluble factors that are released into the systemic circulation. To confirm this in a straightforward manner, we obtained plasma from healthy human volunteers before and after exposure to diesel exhaust (DE) and nitrogen di...

  7. Activated Carbon by Co-pyrolysis and Steam Activation from Particle Board and Melamine Formaldehyde Resin: Production, Adsorption Properties and Techno Economic Evaluation

    Directory of Open Access Journals (Sweden)

    Kenny Vanreppelen

    2013-03-01

    Full Text Available One of the top strategic objectives and research areas in Europe is recovering wood from processing and end of life products. However, there are still several "contaminated" wood products that are not or only partly reused/recycled. Particle board waste which is contaminated with aminoplasts is one of these products. In addition, a considerable amount of aminoplast waste resinis produced for the production of particle board that cannot be re-used or recycled. The chemical properties of these wastes (high nitrogen content of 5.9 wt% and 54.1 wt% for particle board and melamine formaldehyde respectively make them ideal precursors for the production of nitrogenised activated carbon. The profitability of the produced activated carbon is investigated by calculating the net present value, the minimum selling price and performing a Monte Carlo sensitivity analysis. Encouraging results for a profitable production are obtained even though the current assumptions start from a rather pessimistic scenario.

  8. Method for removing soot from exhaust gases

    Energy Technology Data Exchange (ETDEWEB)

    Suib, Steven L.; Dharmarathna, D. A. Saminda; Pahalagedara, Lakshitha R.

    2018-01-16

    A method for oxidizing soot from diesel exhaust gas from a diesel engine. The method involves providing a diesel particulate filter for receiving the diesel exhaust gas; coating a catalyst composition on the diesel particulate filter; and contacting the soot from the diesel exhaust gas with the catalyst coated diesel particulate filter at a temperature sufficient to oxidize the soot to carbon dioxide. The catalyst composition is a doped or undoped manganese oxide octahedral molecular sieve (OMS-2) material. A diesel exhaust gas treatment system that includes a diesel particulate filter for receiving diesel exhaust gas from a diesel engine and collecting soot; and a catalyst composition coated on the diesel particulate filter. The catalyst composition is a doped or undoped manganese oxide octahedral molecular sieve (OMS-2).

  9. Enhancement of the photocatalytic activity of Ferrous Oxide by doping onto the nano-clinoptilolite particles towards photodegradation of tetracycline.

    Science.gov (United States)

    Nezamzadeh-Ejhieh, Alireza; Shirzadi, Arezoo

    2014-07-01

    Photodegradation of tetracycline (TC) aqueous solution by FeO doped onto nano-clinoptilolite particles was investigated using a high pressure Hg lamp as radiation source. Nano-particles of clinoptilolite were prepared using ball-milling of micro crystals of zeolite. The pretreated nano-particles ion exchanged in a ferrous solution and the Fe(II)-exchanged form was calcined at 450°C. All samples were characterized by FT-IR, DRS, SEM and XRD. The degradation extent was determined via UV-Vis absorption spectroscopy and COD. Based on the study of the effect of key operating parameters, the optimal conditions were determined to reach the higher efficiency of the process. The best photocatalytic activity was obtained in presence of the catalyst containing 5.4% FeO. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Sticking transition in a minimal model for the collisions of active particles in quantum fluids

    Science.gov (United States)

    Shukla, Vishwanath; Brachet, Marc; Pandit, Rahul

    2016-10-01

    Particles of low velocity, traveling without dissipation in a superfluid, can interact and emit sound when they collide. We propose a minimal model in which the equations of motion of the particles, including a short-range repulsive force, are self-consistently coupled with the Gross-Pitaevskii equation. We show that this model generates naturally an effective superfluid-mediated attractive interaction between the particles; and we study numerically the collisional dynamics of particles as a function of their incident kinetic energy and the length scale of the repulsive force. We find a transition from almost elastic to completely inelastic (sticking) collisions as the parameters are tuned. We find that aggregation and clustering result from this sticking transition in multiparticle systems.

  11. Research program in elementary particle theory. Progress report, 1975--1976. [Summaries of research activities

    Energy Technology Data Exchange (ETDEWEB)

    Sudarshan, E.C.G.; Ne' eman, Y.

    1976-01-01

    Research on particle theory is summarized including field theory models, phenomenological applications of field theory, strong interactions, the algebraic approach to weak and electromagnetic interactions, and superdense matter. A list of reports is also included. (JFP)

  12. Plant Virus Particles Carrying Tumour Antigen Activate TLR7 and Induce High Levels of Protective Antibody

    OpenAIRE

    Jantipa Jobsri; Alex Allen; Deepa Rajagopal; Michael Shipton; Kostya Kanyuka; Lomonossoff, George P.; Christian Ottensmeier; Diebold, Sandra S.; Stevenson, Freda K.; Natalia Savelyeva

    2015-01-01

    Induction of potent antibody is the goal of many vaccines targeted against infections or cancer. Modern vaccine designs that use virus-like particles (VLP) have shown efficacy for prophylactic vaccination against virus-associated cancer in the clinic. Here we used plant viral particles (PVP), which are structurally analogous to VLP, coupled to a weak idiotypic (Id) tumour antigen, as a conjugate vaccine to induce antibody against a murine B-cell malignancy. The Id-PVP vaccine incorporates a n...

  13. Emotionally exhausting factors in general practitioners’ work

    Science.gov (United States)

    Torppa, M.A.; Kuikka, L.; Nevalainen, M.; Pitkälä, K.H.

    2015-01-01

    Background. Emotional exhaustion is central in burnout syndrome and signals its development. General practitioners’ (GP) work is emotionally challenging but research on these aspects is lacking. Objective. To study the prevalence of emotional exhaustion among GPs and to evaluate how their characteristics and work experiences are associated with emotional exhaustion. Design and methods. A questionnaire survey was carried out among GPs in Finland in 2011 in which questions were posed regarding their experience of emotional exhaustion and items related to their work experiences and professional identity. A statement “I feel burnt out from my job” (never, seldom, sometimes, quite often, or often) enquired about emotional exhaustion. Those responding quite often or often were categorized as emotionally exhausted. Results. Among the GPs, 68% responded (165/244). Of the respondents, 18% were emotionally exhausted. Emotional exhaustion was associated with older age, longer working history, experiences of having too much work, fear and reports of having committed a medical error, low tolerance of uncertainty in their work, and feeling alone at work. No differences in positive work experiences were found. In logistic regression analysis working experience > 5 years (OR 4.1, 95% CI 1.6–10.8; p = 0.0036) and feeling alone at work (OR 2.9, 95% CI 1.2–7.1; p = 0.020) predicted emotional exhaustion, having committed a medical error in the past three months predicted it marginally significantly (OR 2.4, 95% CI 1.0–5.9, p = 0.057), whereas tolerating uncertainty well protected against it (OR 0.2, 95% CI 0.09–0.7; p = 0.0098). Conclusions. Emotional exhaustion among GPs was common and associated with longer working history, having committed a medical error, and feelings of isolation at work. GPs should receive more support throughout their careers. PMID:26311207

  14. Intra-particle migration of mercury in granular polysulfide-rubber-coated activated carbon (PSR-AC).

    Science.gov (United States)

    Kim, Eun-Ah; Masue-Slowey, Yoko; Fendorf, Scott; Luthy, Richard G

    2012-02-01

    The depth profile of mercuric ion after the reaction with polysulfide-rubber-coated activated carbon (PSR-AC) was investigated using micro-X-ray fluorescence (μ-XRF) imaging techniques and mathematical modeling. The μ-XRF results revealed that mercury was concentrated at 0-100 μm from the exterior of the particle after 3 months of treatment with PSR-AC in 10 ppm HgCl(2) aqueous solution. The μ-X-ray absorption near edge spectroscopic (μ-XANES) analyses indicated HgS as a major mercury species, and suggested that the intra-particle mercury transport involved a chemical reaction with PSR polymer. An intra-particle mass transfer model was developed based on either a Langmuir sorption isotherm with liquid phase diffusion (Langmuir model) or a kinetic sorption with surface diffusion (kinetic sorption model). The Langmuir model predicted the general trend of mercury diffusion, although at a slower rate than observed from the μ-XRF map. A kinetic sorption model suggested faster mercury transport, which overestimated the movement of mercuric ions through an exchange reaction between the fast and slow reaction sites. Both μ-XRF and mathematical modeling results suggest mercury removal occurs not only at the outer surface of the PSR-AC particle but also at some interior regions due to a large PSR surface area within an AC particle. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. [Size distribution of particle and polycyclic aromatic hydrocarbons in particle emissions from simulated emission sources].

    Science.gov (United States)

    Fu, Hai-Huan; Tian, Na; Shang, Hui-Bin; Zhang, Bin; Ye, Su-Fen; Chen, Xiao-Qiu; Wu, Shui-Ping

    2014-01-01

    Particles from cooking lampblack, biomass and plastics burning smoke, gasoline vehicular exhausts and gasoline generator exhausts were prepared in a resuspension test chamber and collected using a cascade MOUDI impactor. A total of 18 polycyclic aromatic hydrocarbons (PAHs) associated with particles were analyzed by GC-MS. The results showed that there were two peaks in the range of 0.44-1.0 microm and 2.5-10 microm for cooking lampblack, and only one peak in the range of 0.44-1.0 microm for straw and wood burning smoke. But there were no clear peak for plastics burning smoke. The peak for gasoline vehicular exhausts was found in the range of 2.5-10 microm due to the influence of water vapor associated with particles, while the particles from gasoline generator exhausts were mainly in the range of < or = 2.5 microm (accounting for 93% of the total mass). The peak in 2.5-10 microm was clear for cooking lampblack and gasoline vehicular exhausts. The peak in the range of 0.44-1.0 microm became more and more apparent with the increase of PAHs molecular weight. The fraction of PAH on particles less than 1.0 microm to that on the total particles increased along with PAH's molecular weight. Phenanthrene was the dominant compound for cooking lampblack and combustion smoke, while gasoline vehicular exhausts and generator exhausts were characterized with significantly high levels of naphthalene and benzo[g, h, i] perylene, respectively. The distribution of source characteristic ratios indicated that PAHs from cooking lampblack and biomass burning were close and they were different from those of vehicular exhausts and generator exhausts.

  16. Annealing effect on the particle size and chemical composition of activated carbon obtained from vacuum furnace of teak sawdust

    Energy Technology Data Exchange (ETDEWEB)

    Armynah, B., E-mail: dtahir@fmipa.unhas.ac.id; Tahir, D., E-mail: dtahir@fmipa.unhas.ac.id; Jaya, N., E-mail: dtahir@fmipa.unhas.ac.id [Department of Physics, Hasanuddin University, Makassar 90245 (Indonesia)

    2014-09-25

    Activated carbon was produced from sawdust by using physical method in a high temperature vacuum furnace without additional chemical. Fast pyrolysis process was carried out prior in fluidized a bed furnace to produce char before activation process. Experiments were conducted to investigate the influence of various process parameters such as particle size, activation temperature and activation time on the quality of the activated carbon. In addition, the chemical composition studies were done by using x-ray fluorescence (XRF) spectroscopy. The crystallite sizes were calculated by using Scherer equation based on x-ray diffraction (XRD) spectroscopy data. The pyrolysis temperature and time were varied from 600°C to 900°C and from 3 hours to 6 hours, respectively. The particle size of activated carbon was increase with increasing temperature. The composition and crystallite size of the prepared activated carbon was compared with the non-activated carbon. The results indicated that the teak sawdust carbon could be employed as a low cost alternative to produce commercial activated carbon.

  17. Factors affecting swimming performance of fasted rainbow trout with implications of exhaustive exercise on overwinter mortality

    Science.gov (United States)

    Simpkins, D.G.; Hubert, W.A.; Del Rio, C.M.; Rule, D.C.

    2004-01-01

    We evaluated the effects of body size, water temperature, and sustained swimming activity on swimming performance and the effects of exhaustive exercise on mortality of fasted juvenile rainbow trout. Fasting caused swimming performance to decline more rapidly for small fish than large fish, and warmer water temperatures and sustained swimming activity further decreased swimming performance. Exhaustive exercise increased mortality among fasted fish. Our observations suggest that juvenile rainbow trout with little or no food intake during winter can swim for long periods of time with little effect on mortality, but swimming to exhaustion can enhance mortality, especially among the smallest juveniles.

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

    Science.gov (United States)

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

    2011-01-01

    Decreasing the particle size of powdered activated carbon (PAC) by pulverization increases its adsorption capacities for natural organic matter (NOM) and polystyrene sulfonate (PSS, which is used as a model adsorbate). A shell adsorption mechanism in which NOM and PSS molecules do not completely penetrate the adsorbent particle and instead preferentially adsorb near the outer surface of the particle has been proposed as an explanation for this adsorption capacity increase. In this report, we present direct evidence to support the shell adsorption mechanism. PAC particles containing adsorbed PSS were sectioned with a focused ion beam, and the solid-phase PSS concentration profiles of the particle cross-sections were directly observed by means of field emission-scanning electron microscopy/energy-dispersive X-ray spectrometry (FE-SEM/EDXS). X-ray emission from sulfur, an index of PSS concentration, was higher in the shell region than in the inner region of the particles. The X-ray emission profile observed by EDXS did not agree completely with the solid-phase PSS concentration profile predicted by shell adsorption model analysis of the PSS isotherm data, but the observed and predicted profiles were not inconsistent when the analytical errors were considered. These EDXS results provide the first direct evidence that PSS is adsorbed mainly in the vicinity of the external surface of the PAC particles, and thus the results support the proposition that the increase in NOM and PSS adsorption capacity with decreasing particle size is due to the increase in external surface area on which the molecules can be adsorbed. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Changes of pedaling technique and muscle coordination during an exhaustive exercise

    National Research Council Canada - National Science Library

    Dorel, Sylvain; Drouet, Jean-Marc; Couturier, Antoine; Champoux, Yvan; Hug, François

    2009-01-01

    .... We designed the present study to test the hypothesis that these alterations in the biomechanics of pedaling, which occur during exhaustive exercise, are linked to changes in the activity patterns of lower limb muscles...

  20. Diesel Exhaust-Induced Pulmonary and Cardiovascular Impairment: The Role of Hypertension Intervention

    Science.gov (United States)

    Background–Exposure to diesel exhaust (DE) particles and associated gases is linked to cardiovascular impairments; however the susceptibility of hypertensive individuals is less well understood. Objective–1) To determine cardiopulmonary effects of gas-phase versus whole-DE, and 2...

  1. 40 CFR 90.407 - Engine inlet and exhaust systems.

    Science.gov (United States)

    2010-07-01

    ... exhaust emission compliance over the full range of air inlet filter systems and exhaust muffler systems. (b) The air inlet filter system and exhaust muffler system combination used on the test engine must...

  2. Exhaust gas recirculation system for an internal combustion engine

    Science.gov (United States)

    Wu, Ko-Jen

    2013-05-21

    An exhaust gas recirculation system for an internal combustion engine comprises an exhaust driven turbocharger having a low pressure turbine outlet in fluid communication with an exhaust gas conduit. The turbocharger also includes a low pressure compressor intake and a high pressure compressor outlet in communication with an intake air conduit. An exhaust gas recirculation conduit fluidly communicates with the exhaust gas conduit to divert a portion of exhaust gas to a low pressure exhaust gas recirculation branch extending between the exhaust gas recirculation conduit and an engine intake system for delivery of exhaust gas thereto. A high pressure exhaust gas recirculation branch extends between the exhaust gas recirculation conduit and the compressor intake and delivers exhaust gas to the compressor for mixing with a compressed intake charge for delivery to the intake system.

  3. Decreased paraoxonase-1 activity is associated with alterations of high-density lipoprotein particles in chronic liver impairment.

    Science.gov (United States)

    Marsillach, Judit; Aragonès, Gerard; Mackness, Bharti; Mackness, Michael; Rull, Anna; Beltrán-Debón, Raúl; Pedro-Botet, Juan; Alonso-Villaverde, Carlos; Joven, Jorge; Camps, Jordi

    2010-05-14

    Paraoxonase-1 (PON1), a lactonase synthesized by the liver, circulates in blood bound to high-density lipoproteins (HDL). This enzyme is thought to degrade oxidized phospholipids and play an important role in the organism's antioxidant and anti-inflammatory system. Chronic liver diseases are characterized by decreased serum PON1 activity. The aim of the present study was to investigate the compositional changes in HDL that could influence PON1 activity in liver impairment. The study was performed in samples from five patients with advanced liver cirrhosis and with preserved renal function, chosen on the basis of having low serum PON1 activity and high serum PON1 concentration. As a control group, we accessed five healthy volunteers from among our hospital staff. Lipid and protein compositional analysis of lipoprotein particles were done by high-performance liquid chromatography, gel electrophoresis, and Western-Blot. HDL particles from cirrhotic patients had an increased phospholipid content that was inversely correlated to PON1 activity. The HDL particles contained high levels of PON1 that corresponded, in part, to an immunoreactive protein of high molecular weight (55 kDa) not present in control subjects. This protein was identified as glycosylated PON1 and was also present in biopsies from patients with steatosis and from rats with CCl(4)-induced hepatic impairment. These changes were associated with an increased plasma concentration of markers of oxidative stress, inflammation and fibrogenesis. Abnormalities in the composition of lipids and proteins of HDL particles, including PON1 glycosylation, are associated with the decrease in serum PON1 activity in patients with liver disease. These alterations may adversely affect the protective role of HDL against oxidative stress and inflammation in these patients.

  4. Decreased paraoxonase-1 activity is associated with alterations of high-density lipoprotein particles in chronic liver impairment

    Directory of Open Access Journals (Sweden)

    Joven Jorge

    2010-05-01

    Full Text Available Abstract Background Paraoxonase-1 (PON1, a lactonase synthesized by the liver, circulates in blood bound to high-density lipoproteins (HDL. This enzyme is thought to degrade oxidized phospholipids and play an important role in the organism's antioxidant and anti-inflammatory system. Chronic liver diseases are characterized by decreased serum PON1 activity. The aim of the present study was to investigate the compositional changes in HDL that could influence PON1 activity in liver impairment. Methods The study was performed in samples from five patients with advanced liver cirrhosis and with preserved renal function, chosen on the basis of having low serum PON1 activity and high serum PON1 concentration. As a control group, we accessed five healthy volunteers from among our hospital staff. Lipid and protein compositional analysis of lipoprotein particles were done by high-performance liquid chromatography, gel electrophoresis, and Western-Blot. Results HDL particles from cirrhotic patients had an increased phospholipid content that was inversely correlated to PON1 activity. The HDL particles contained high levels of PON1 that corresponded, in part, to an immunoreactive protein of high molecular weight (55 kDa not present in control subjects. This protein was identified as glycosylated PON1 and was also present in biopsies from patients with steatosis and from rats with CCl4-induced hepatic impairment. These changes were associated with an increased plasma concentration of markers of oxidative stress, inflammation and fibrogenesis. Conclusion Abnormalities in the composition of lipids and proteins of HDL particles, including PON1 glycosylation, are associated with the decrease in serum PON1 activity in patients with liver disease. These alterations may adversely affect the protective role of HDL against oxidative stress and inflammation in these patients.

  5. Study of typical space wave-particle coupling events possibly related with seismic activity

    CERN Document Server

    Zhang, Zhenxia; Shen, Xuhui; Li, Xinqiao; Wu, Shugui

    2014-01-01

    Based on the DEMETER satellite, we found two space wave-particle coupling events during February 2010 taking place in the range of McIlwain parameter $L$($1.27\\sim1.37$). There are strong spatial and temporal correlation between the particle bursts(PBs) and the electromagnetic disturbances of the coupling events. The two PBs show different energy spectrum characteristics, while the corresponding electromagnetic disturbances concentrated on different frequencies range. In agreement with the prediction of the theory of wave-particle interaction, we conclude that the two wave-particle interactions can be probably explained as following: one is electron dominant precipitation with energy of $0.09\\sim0.2$ MeV induced by VLF electromagnetic wave with the frequency of $14\\sim20$ kHz, and another is proton dominant precipitation with energy of $0.65\\sim2.85$ MeV induced by VLF electromagnetic wave with the frequency of $\\le 100$ Hz. For the first time, those particle bursts origin, from electron or proton detected by...

  6. Comprehensive particle characterization of modern gasoline and diesel passenger cars at low ambient temperatures

    Science.gov (United States)

    Mathis, Urs; Mohr, Martin; Forss, Anna-Maria

    Particle measurements were performed in the exhaust of five light-duty vehicles (Euro-3) at +23, -7, and -20 °C ambient temperatures. The characterization included measurements of particle number, active surface area, number size distribution, and mass size distribution. We investigated two port-injection spark-ignition (PISI) vehicles, a direct-injection spark-ignition (DISI) vehicle, a compressed ignition (CI) vehicle with diesel particle filter (DPF), and a CI vehicle without DPF. To minimize sampling effects, particles were directly sampled from the tailpipe with a novel porous tube diluter at controlled sampling parameters. The diluted exhaust was split into two branches to measure either all or only non-volatile particles. Effect of ambient temperature was investigated on particle emission for cold and warmed-up engine. For the gasoline vehicles and the CI vehicle with DPF, the main portion of particle emission was found in the first minutes of the driving cycle at cold engine start. The particle emission of the CI vehicle without DPF was hardly affected by cold engine start. For the PISI vehicles, particle number emissions were superproportionally increased in the diameter size range from 0.1 to 0.3 μm during cold start at low ambient temperature. Based on the particle mass size distribution, the DPF removed smaller particles ( dp0.5μm). No significant effect of ambient temperature was observed when the engine was warmed up. Peak emission of volatile nanoparticles only took place at specific conditions and was poorly repeatable. Nucleation of particles was predominately observed during or after strong acceleration at high speed and during regeneration of the DPF.

  7. Helium exhaust in plasmas with strong radiative edge cooling

    Science.gov (United States)

    Samm, U.; Boedo, J.; Bertschinger, G.; Dippel, K. H.; Euringer, H.; Finken, K. H.; Gray, D.; Hillis, D.; Pospieszczyk, A.; Reiter, D.; Tokar, M.; Unterberg, B.

    1992-12-01

    The compatibility of radiative edge cooling by neon injection and He exhaust with the pump limiter ALT-II is studied on TEXTOR. It is demonstrated that in plasmas with strong auxiliary heating (2 MW NBI) and with the highest average electron densities (¯ ne≈5.5×10 19 m -3) the effective confinement time τ p* for He has a minimum. This good pumping performance is maintained even for cases in which up to 90% of the heating power is radiated from the plasma boundary (cold radiative edge). The processes inside the scoops of the pump limiter (neutral particle transport, re-ionization) and the variation of particle confinement in the main plasma dominate this behavior.

  8. Size-Dependent Photodynamic Anticancer Activity of Biocompatible Multifunctional Magnetic Submicron Particles in Prostate Cancer Cells

    Directory of Open Access Journals (Sweden)

    Kyong-Hoon Choi

    2016-09-01

    Full Text Available In this study, newly designed biocompatible multifunctional magnetic submicron particles (CoFe2O4-HPs-FAs of well-defined sizes (60, 133, 245, and 335 nm were fabricated for application as a photosensitizer delivery agent for photodynamic therapy in cancer cells. To provide selective targeting of cancer cells and destruction of cancer cell functionality, basic cobalt ferrite (CoFe2O4 particles were covalently bonded with a photosensitizer (PS, which comprises hematoporphyrin (HP, and folic acid (FA molecules. The magnetic properties of the CoFe2O4 particles were finely adjusted by controlling the size of the primary CoFe2O4 nanograins, and secondary superstructured composite particles were formed by aggregation of the nanograins. The prepared CoFe2O4-HP-FA exhibited high water solubility, good MR-imaging capacity, and biocompatibility without any in vitro cytotoxicity. In particular, our CoFe2O4-HP-FA exhibited remarkable photodynamic anticancer efficiency via induction of apoptotic death in PC-3 prostate cancer cells in a particle size- and concentration-dependent manner. This size-dependent effect was determined by the specific surface area of the particles because the number of HP molecules increased with decreasing size and increasing surface area. These results indicate that our CoFe2O4-HP-FA may be applicable for photodynamic therapy (PDT as a PS delivery material and a therapeutic agent for MR-imaging based PDT owing to their high saturation value for magnetization and superparamagnetism.

  9. Contrasting macrophage activation by fine and ultrafine titanium dioxide particles is associated with different uptake mechanisms

    Directory of Open Access Journals (Sweden)

    Schmidt Annette M

    2011-10-01

    Full Text Available Abstract Inhalation of (nanoparticles may lead to pulmonary inflammation. However, the precise mechanisms of particle uptake and generation of inflammatory mediators by alveolar macrophages (AM are still poorly understood. The aim of this study was to investigate the interactions between particles and AM and their associated pro-inflammatory effects in relation to particle size and physico-chemical properties. NR8383 rat lung AM were treated with ultrafine (uf, fine (f TiO2 or fine crystalline silica (DQ12 quartz. Physico-chemical particle properties were investigated by transmission electron microscopy, elemental analysis and thermogravimetry. Aggregation and agglomeration tende