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Ambient Air (ambient + air)
Terms modified by Ambient Air Selected AbstractsPrediction of Droplet Velocities and Rain Out in Horizontal Isothermal Free Jet Flows of Air and Viscous Liquid in Stagnant Ambient AirCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 11 2007S. Al Rabadi Abstract Two-dimensional phase Doppler anemometer measurements of droplet size and velocity conducted under several nozzle conditions and a systematic variation of the air mass flow quality and liquid phase viscosity show that the air entrainment process is enhanced when keeping all test conditions constant except for increasing the Newtonian liquid viscosity above of that of water. A two-zone entrainment model based on a variable two-phase entrainment coefficient is proposed with the normalized axial distance allowing for a change in the jet angle. Thus, the jet perimeter is lower and the breakup length is longer in the case of air/relatively higher viscosity liquid phase. It provides the most accurate reproduction of the experimental droplet velocity in comparison with that of other models in the literature and, hence, is recommended for the prediction of the droplet velocity in the case of two-phase air/liquid phase free jet flow in stagnant ambient air. A model for predicting the droplet rain out, considering the droplet trajectories in the free jet flow, allows also for an adequate reproduction of the experimental data. [source] Emission of legacy chlorinated pesticides from agricultural and orchard soils in British Columbia, CanadaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2006Terry F. Bidleman Abstract Air samples were collected above agricultural fields in the Fraser Valley and orchards in the Okanagan Valley, British Columbia, Canada, to investigate volatilization of organochlorine pesticides used in the past. Concentrations of pesticides in air were elevated over soils that contained higher residues. Soil/air fugacity ratios at sites with the higher soil residues were calculated relative to air sampled at 40 cm height and background air. The fugacity ratios in the first case indicated net volatilization or soil-air equilibrium for most compounds and occasional net deposition for p,p, -dichlorodiphenyldichloroethene (p,p, -DDE), whereas those in the second case showed a strong potential for net volatilization of all compounds. The enantiomer fraction (EF) of chiral compounds ,-hexachlorocyclohexane (,-HCH), trans -chlordane, cis -chlordane, and o,p, -DDT were determined in overlying air samples and soils. Enantiomer fractions in air corresponded to those in soils at fields in which soil concentrations were high but were decoupled from soil signatures at fields with low soil residues. Mean EFs in air sampled over soils were significantly (p < 0.001) nonracemic for ,-HCH and the chlordanes and agreed with published EFs in regional ambient air. The mean EF of o,p, -DDT for all air samples did not show a significant deviation from racemic EFs (p > 0.2), but EFs of individual samples reflected the ambivalent nature of o,p, -DDT degradation, sometimes preferring the (+) enantiomer and other times the (,) enantiomer. The study indicates that soils are continuing to emit "legacy" pesticides into the regional atmosphere. [source] A dynamic process convolution approach to modeling ambient particulate matter concentrationsENVIRONMETRICS, Issue 1 2008Catherine A. Calder Abstract Elevated levels of particulate matter (PM) in the ambient air have been shown to be associated with certain adverse human health effects. As a result, monitoring networks that track PM levels have been established across the United States. Some of the older monitors measure PM less than 10 µm in diameter (PM10), while the newer monitors track PM levels less than 2.5 µm in diameter (PM2.5); it is now believed that this fine component of PM is more likely to be related to the negative health effects associated with PM. We propose a bivariate dynamic process convolution model for PM2.5 and PM10 concentrations. Our aim is to extract information about PM2.5 from PM10 monitor readings using a latent variable approach and to provide better space-time interpolations of PM2.5 concentrations compared to interpolations made using only PM2.5 monitoring information. We illustrate the approach using PM2.5 and PM10 readings taken across the state of Ohio in 2000. Copyright © 2007 John Wiley & Sons, Ltd. [source] Increased myocardial matrix metalloproteinases in hypoxic newborn pigs during resuscitation: effects of oxygen and carbon dioxideEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 7 2004W. B. Borke Abstract Background, Perinatal asphyxia is associated with cardiac dysfunction, and it is important to prevent further tissue injury during resuscitation. There is increasing evidence that myocardial matrix metalloproteinases (MMPs) are involved in myocardial hypoxaemia,reoxygenation injury. Objective, To assess MMPs and antioxidant capacity in newborn pigs after global ischaemia and subsequent resuscitation with ambient air or 100% O2 at different PaCO2 -levels. Methods, Newborn pigs (12,36 h of age) were resuscitated for 30 min by ventilation with 21% or 100% O2 at different PaCO2 levels after a hypoxic insult, and thereafter observed for 150 min. In myocardial tissue extracts, MMPs were analyzed by gelatin zymography and broad matrix-degrading capacity (total MMP). Total endogenous antioxidant capacity in myocardial tissue extracts was measured by the oxygen radical absorbance capacity (ORAC) assay. Results, Matrix metalloproteinase-2 more than doubled from baseline values (P < 0·001), and was higher in piglets resuscitated with 100% O2 than with ambient air (P = 0·012). The ORAC value was considerably decreased (P < 0·001). In piglets with elevated PaCO2, total MMP-activity in the right ventricle was more increased than in the left ventricle (P = 0·008). In the left ventricle, total MMPactivity was higher in the piglets with low PaCO2 than in the piglets with elevated PaCO2 (P = 0·013). Conclusion, In hypoxaemia-reoxygenation injury the MMP-2 level was highly increased and was most elevated in the piglets resuscitated with 100% O2. Antioxidant capacity was considerably decreased. Assessed by total MMP-activity, elevated PaCO2 during resuscitation might protect the left ventricle, and probably increase right ventricle injury of the myocardium. [source] Hyperbaric Oxygen Does Not Prevent Neurologic Sequelae after Carbon Monoxide PoisoningACADEMIC EMERGENCY MEDICINE, Issue 1 2002Benjamin Gilmer MS Abstract Delayed neurologic sequelae occur in up to 40% of severe carbon monoxide (CO) poisonings. Conflicting clinical data support the efficacy of hyperbaric oxygen (HBO) therapy in the acute treatment of CO poisoning. Objective: To determine whether oxygen therapy reduces neurologic sequelae after CO poisoning in mice. Methods: Male Swiss-Webster mice were exposed to CO at 1,000 ppm for 40 minutes and then 50,000 ppm until loss of consciousness (LOC) (4-9 additional minutes). Total time of both phases of CO exposure was 40-49 minutes. Treatment included HBO with 3 atmospheres (ATA) 100% oxygen, normobaric oxygen (NBO) with 1 ATA 100% oxygen, or ambient air 15 minutes after LOC. All animals underwent passive avoidance training and memory was assessed by measuring step-down latency (SDL) and step-up latency (SUL) seven days following CO exposure. Results: Carbon monoxide poisoning induced significant memory deficits (SDLCO= 156 sec; SULCO= 75%) compared with nonpoisoned (NP) animals (SDLNP= 272 sec; SULNP= 100%). Both HBO and NBO did not prevent these neurologic sequelae. Furthermore, no significant neurobehavioral differences were found between HBO and NBO. Histologic examination of the CA1 layer of the hippocampus for pyknotic cells showed significant damage from CO in the air-treated animals (9.6%) but not in the nonpoisoned animals (3.8%). No significant neuroprotection was seen histologically with NBO and HBO compared with ambient air. Conclusions: These results suggest that HBO is not effective in preventing neurologic sequelae in mice and that there is no benefit of HBO over NBO following severe CO neurotoxicity. [source] Organic Electronics: High Tg Cyclic Olefin Copolymer Gate Dielectrics for N,N,-Ditridecyl Perylene Diimide Based Field-Effect Transistors: Improving Performance and Stability with Thermal Treatment (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 16 2010Mater. Abstract A novel application of ethylene-norbornene cyclic olefin copolymers (COC) as gate dielectric layers in organic field-effect transistors (OFETs) that require thermal annealing as a strategy for improving the OFET performance and stability is reported. The thermally-treated N,N, -ditridecyl perylene diimide (PTCDI-C13)-based n-type FETs using a COC/SiO2 gate dielectric show remarkably enhanced atmospheric performance and stability. The COC gate dielectric layer displays a hydrophobic surface (water contact angle = 95° ± 1°) and high thermal stability (glass transition temperature = 181 °C) without producing crosslinking. After thermal annealing, the crystallinity improves and the grain size of PTCDI-C13 domains grown on the COC/SiO2 gate dielectric increases significantly. The resulting n-type FETs exhibit high atmospheric field-effect mobilities, up to 0.90 cm2 V,1 s,1 in the 20 V saturation regime and long-term stability with respect to H2O/O2 degradation, hysteresis, or sweep-stress over 110 days. By integrating the n-type FETs with p-type pentacene-based FETs in a single device, high performance organic complementary inverters that exhibit high gain (exceeding 45 in ambient air) are realized. [source] High Tg Cyclic Olefin Copolymer Gate Dielectrics for N,N,-Ditridecyl Perylene Diimide Based Field-Effect Transistors: Improving Performance and Stability with Thermal TreatmentADVANCED FUNCTIONAL MATERIALS, Issue 16 2010Jaeyoung Jang Abstract A novel application of ethylene-norbornene cyclic olefin copolymers (COC) as gate dielectric layers in organic field-effect transistors (OFETs) that require thermal annealing as a strategy for improving the OFET performance and stability is reported. The thermally-treated N,N, -ditridecyl perylene diimide (PTCDI-C13)-based n-type FETs using a COC/SiO2 gate dielectric show remarkably enhanced atmospheric performance and stability. The COC gate dielectric layer displays a hydrophobic surface (water contact angle = 95° ± 1°) and high thermal stability (glass transition temperature = 181 °C) without producing crosslinking. After thermal annealing, the crystallinity improves and the grain size of PTCDI-C13 domains grown on the COC/SiO2 gate dielectric increases significantly. The resulting n-type FETs exhibit high atmospheric field-effect mobilities, up to 0.90 cm2 V,1 s,1 in the 20 V saturation regime and long-term stability with respect to H2O/O2 degradation, hysteresis, or sweep-stress over 110 days. By integrating the n-type FETs with p-type pentacene-based FETs in a single device, high performance organic complementary inverters that exhibit high gain (exceeding 45 in ambient air) are realized. [source] Carbon dioxide generation calorimetry,Errors induced by the simplifying assumptions in the standard test methodsFIRE AND MATERIALS, Issue 2 2009S. Brohez Abstract Carbon dioxide generation (CDG) calorimetry is commonly used for measuring heat release rates of materials. Calorimetric equation provided in the ASTM E 2058 and the NFPA code 287 is a simplified equation since the water content in the ambient air and the fumes as well as the expansion factor of the combustion gases are neglected. This paper provides general equation for CDG calorimetry based on the Tewarson formulation. A comparison is proposed between the Standard test methods (simplified equation) and the general one. It is shown that the errors induced by the simplifying assumptions are negligible for oxygen depletion factor values commonly encountered in the Fire Propagation Apparatus (where large dilution factors of the combustion gases are used before the measurements of species concentrations). Copyright © 2009 John Wiley & Sons, Ltd. [source] Numerical simulation of natural convection heat transfer in the open space between two horizontal circular planesHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 6 2001Hideki Tokanai Abstract Numerical simulations were conducted for natural convection heat transfer in a narrow gap between two horizontal plates in air. The lower plate is an infinite plate with a circular heating zone. The upper one is the bottom of a vertical cylinder, which is placed right above the circular heated plate and kept at room temperature. A set of Navier,Stokes equations and an energy equation are analyzed for a variety of combinations of gap clearance and Rayleigh number. The calculated average heat transfer values are shown to be in good agreement with the experimentally obtained ones reported in a previous paper. From the obtained isotherms, streamlines, and local Nusselt numbers, it is found that two types of convection appear in the gap space according to the conditions of Rayleigh number and gap clearance: one is a simple convection due to a single renewal flow which replaces heated air with ambient air and the other is a combined convection due to several vortex flows and a renewal flow. Furthermore, the flow rate of each flow controls the rate of heat transfer from the limited area which is covered by each flow. From this fact, the validity of the previously proposed heat transfer correlation is briefly discussed. © 2001 Scripta Technica, Heat Trans Asian Res, 30(6): 485,502, 2001 [source] A One-Step Method for the Growth of Ga2O3 -Nanorod-Based White-Light-Emitting PhosphorsADVANCED MATERIALS, Issue 35 2009Sampathkumar Chrisolite Vanithakumari A one-step synthesis of Ga2O3 nanorods by heating molten gallium in ambient air at high temperatures is presented. The high-temperature synthesis creates oxygen vacancies and incorporates nitrogen from the environment. The oxygen vacancy in Ga2O3 is responsible for the emission in the blue,green region, while nitrogen in Ga2O3 is responsible for red emission. [source] Enumeration of Campylobacter spp. on the surface and within chicken breast filletsJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2007P. Luber Abstract Aim:, To investigate how many Campylobacter bacteria are present on the surface and inside chicken breast fillets, with a focus on generating data distributions which can be used in risk assessments for this pathogen,commodity combination. Methods and Results:, We analysed 100 fresh retail chicken breast fillets (skinless and deboned) by means of a rinse sample for surface and 55 fillets for internal pathogen contamination using 10 g meat and a most probable number technique. Prevalence was 87% on the surface and 20% in the deep tissue. The mean number of Campylobacter on the surface of the fillets was 1903 CFU, with a median of 537 CFU and a maximum of 38 905 CFU. Campylobacter counts inside the tissue were <1 CFU g,1 meat (mean = 0·24 CFU, median = 0·15 CFU, maximum = 0·74 CFU). In addition, we investigated the influence of the type of package on the occurrence of the pathogen. Data provide an indication of less favourable conditions for survival of the pathogen on chicken meat packed under a modified atmosphere of carbon dioxide in nitrogen, in comparison with ambient air or vacuumed packages. Conclusions:, Given the high numbers of the pathogen on the chicken meat surface in comparison with low levels of internal contamination, it can be concluded that cross-contamination during the preparation of contaminated chicken is a more important pathway for consumers' exposure to Campylobacter than the consumption of undercooked meat. Significance and Impact of the Study:, The detailed quantitative data on the occurrence of C. jejuni and C. coli on the surface and inside chicken meat presented here can be useful for future probabilistic exposure assessments. [source] Refractive-index anisotropy and optical dispersion in films of deoxyribonucleic acid,JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Anna Samoc Abstract We have determined the refractive indices in the directions parallel and perpendicular to the surface plane of films of deoxyribonucleic acid (DNA) and their wavelength dispersion. These parameters are fundamental for understanding the properties of waveguiding structures containing DNA-based photonic materials. The orientation of DNA molecules in films and their optical properties are sensitive to the film fabrication and environmental conditions influencing the structure. Prism coupling measurements show ambient-humidity-related changes in the refractive index, birefringence, and anisotropy of the alignment of the DNA molecules in the films studied. These films were 0.5,5 ,m thick, were prepared by both spin coating and casting from aqueous solutions containing 0.1,3 wt % DNA, and were measured in ambient air with relative humidities of 37,58%. The optical properties of the films and the orientation of the DNA molecules are discussed with respect to the mechanism for the formation of the polymer liquid-crystalline phases during film deposition. The dispersion of the refractive indices in films of native DNA has been derived from interference fringes in absorption and reflection spectra in the wavelength range of 350,2700 nm through the fitting of the positions of the fringes with the Sellmeier dispersion formula in combination with the prism coupling data. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 236,245, 2007 [source] Active Packaging of Fresh Chicken Breast, with Allyl Isothiocyanate (AITC) in Combination with Modified Atmosphere Packaging (MAP) to Control the Growth of PathogensJOURNAL OF FOOD SCIENCE, Issue 2 2010Joongmin Shin ABSTRACT:,Listeria monocytogenes,and,Salmonella typhimurium,are major bacterial pathogens associated with poultry products. Ally isothiocyanate (AITC), a natural antimicrobial compound, is reportedly effective against these pathogenic organisms. A device was designed for the controlled release of AITC with modified atmosphere packaging (MAP), and then evaluated for its ability to control the growth of,L. monocytogenes,and,S. typhimurium,on raw chicken breast during refrigerated storage. In order to obtain controlled release during the test period, a glass vial was filled with AITC and triglyceride. It was then sealed using high-density polyethylene film. The release of AITC was controlled by the concentration (mole fraction) of AITC in the triglyceride and by the AITC vapor permeability through the film. The fresh chicken samples were inoculated with one or the other of the pathogens at 104 CFU/g, and the packages (with and without AITC-controlled release device) were flushed with ambient air or 30% CO2/70% N2 before sealing, and then stored at 4 °C for up to 21 d. The maximum reduction in MAP plus AITC (compared to MAP alone) was 0.77 log CFU/g for,L.,monocytogenes,and 1.3 log CFU/g for,S.,typhimurium. The color of the chicken breast meat was affected by the concentration of AITC. Overall, a release rate of 0.6 ,g/h of AITC was found to not affect the color, whereas at 1.2 ,g/h of AITC the surface of the chicken was discolored. [source] Microbial Reduction Efficiencies of Filtration, Electrostatic Polarization, and UV Components of a Germicidal Air Cleaning SystemJOURNAL OF FOOD SCIENCE, Issue 6 2002C.J. Cundith ABSTRACT: This study determined the effectiveness of components of a germicidal air-cleaning system involving filtration, electrostatic polarization, and UV light on the reduction of airborne bacteria and molds. The filter alone, filter and electrostatic polarization combined, and the filter, electrostatic polarization, and UV light were found to be effective (P < 0.05) in reducing a given concentration of M. luteus and S. marcescens by 90 to 92%. The same components were also found to be effective (P < 0.05) in reducing indigenous airborne bacteria and molds from ambient air in processing plant production conditions by 62 to 77% after only 1 pass through the filtration system. A germicidal air-filtration system utilizing electrostatic polarization and ultraviolet light can be used to reduce the chance of contaminating surfaces with airborne bacteria and molds. [source] Three-bed PVSA process for high-purity O2 generation from ambient airAICHE JOURNAL, Issue 11 2005Jeong-Geun Jee Abstract A three-bed PVSA (pressure vacuum swing adsorption) process, combining equilibrium separation with kinetic separation, was developed to overcome the 94% O2 purity restriction inherent to air separation in the adsorption process. To produce 97+% and/or 99+% purity O2 directly from air, the PVSA process with two zeolite 10X beds and one CMS bed was executed at 33.44,45.60 to 253.31 kPa. In addition, the effluent gas from the CMS bed to be used for O2 purification was backfilled to the zeolite 10X bed to improve its purity, recovery, and productivity in bulk separation of the air. PVSA I, which made use of a single blowdown/backfill step, produced an O2 product with a purity of 95.4,97.4% and a recovery of 43.4,84.8%, whereas PVSA II, which used two consecutive blowdown/backfill steps, produced O2 with a purity of 98.2,99.2% and a recovery of 47.2,63.6%. Because the primary impurity in the O2 product was Ar, the amounts of N2 contained in the product were in the range of 4000,5000 ppm at PVSA I and several tens of ppm at PVSA II. A nonisothermal dynamic model incorporating mass, energy, and momentum balances was applied to predict the process dynamics. Using the linear driving force (LDF) model with constant diffusivity for the equilibrium separation bed and a modified LDF model with concentration dependency of the diffusion rate for the kinetic separation bed, the dynamic model was able to accurately predict the results of the experiment. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source] Evaluation of solution oxygenation requirements for azonitrile-based oxidative forced degradation studies of pharmaceutical compoundsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 7 2006Eric D. Nelson Abstract AIBN and ACVA oxidative forced degradation models are examined for two drug molecules whose predominant oxidation chemistries arise from different reaction mechanisms (i.e., free radical vs. nucleophilic). Stress was conducted under a variety of initiator concentrations, and under ambient and pressurized oxygen atmospheres. In each case examined, the azonitrile initiator solutions served as a good predictive model of the major oxidative degradation products observed in pharmaceutical formulations. At low to moderate inititator concentrations, the degradation product distributions and degree of reactivity were similar for samples stored in ambient and pressurized oxygen environments. These results are rationalized with reference to the oxygen consumption kinetics of AIBN and ACVA solutions as a function of initiator concentration. The data suggests that ambient air provides sufficient oxygen to enable chain propagation of peroxy radicals in azonitrile solutions of concentrations appropriate to the forced degradation of pharmaceutical compounds. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95: 1527,1539, 2006 [source] A BATCH CULTURE METHOD FOR MICROALGAE AND CYANOBACTERIA WITH CO2 SUPPLY THROUGH POLYETHYLENE MEMBRANES,JOURNAL OF PHYCOLOGY, Issue 4 2010Yvonne Pörs A new method for CO2 supply to photoautotrophic organisms was developed, and its applicability for measuring specific growth rates in shaken batch cultures of cyanobacteria and unicellular algae was shown. Small bags containing a concentrated carbonate buffer with a CO2 partial pressure of 32 mbar were prepared from a thin foil of low density polyethylene (LDPE). These bags were inserted as CO2 reservoirs (CRs) into polystyrene culture flasks with gas-permeable screw caps, which were suitable to photometric growth measurement. CO2 was released directly into the medium with membrane-controlled kinetics. The CRs were not depleted within 1 week, although the atmosphere in the culture vessel exchanged rapidly with the ambient air. Rates of initial growth and final densities of the cultures of six different unicellular algal species and one cyanobacterium were markedly increased by diffusive CO2 supply from the CR. In the presence of a CR, growth was exponential during the first 2 d in all cultures studied. The method described allowed a high number of measurements of specific growth rates with relatively simple experimental setup. [source] Effects of CRF1 -Receptor and Opioid-Receptor Antagonists on Dependence-Induced Increases in Alcohol Drinking by Alcohol-Preferring (P) RatsALCOHOLISM, Issue 9 2008Nicholas W. Gilpin Background:, Selective breeding of rats over generations and induction of alcohol dependence via chronic vapor inhalation both enhance alcohol consumption in animal models. The purpose of this study was to determine whether dependence-induced increases in alcohol consumption by P rats is sensitive to naltrexone, a general opioid receptor antagonist (but with highest affinity at the ,-opioid receptor at low doses), and the recently characterized small molecule CRF1 -receptor antagonist MPZP (N,N -bis(2-methoxyethyl)-3-(4-methoxy-2-methylphenyl)-2,5-dimethyl-pyrazolo[1,5- a]pyrimidin-7-amine). Methods:, P rats (n = 20) were trained to respond for alcohol and water in a 2-lever operant situation during daily 30-minute sessions. P rats were then matched for alcohol intake and exposed to chronic intermittent alcohol vapor (n = 10) or ambient air (n = 10) for approximately 10 weeks. All rats were then administered MPZP and naltrexone in 2 separate and consecutive Latin-square designs. Results:, MPZP attenuated dependence-induced increases in alcohol intake by P rats while having no effect on alcohol consumption by nondependent controls. Conversely, operant alcohol responding was reduced similarly in dependent and nondependent P rats by naltrexone. Conclusions:, These results confirm a role for brain CRF1 -receptor systems in dependence-induced changes in the reinforcing properties of alcohol, and CRF1 -receptor blockade appears to suppress dependence-induced drinking at lower doses in P rats relative to other rat lines. Therefore, brain CRF1 -receptor systems are important in the regulation of dependence-induced alcohol consumption, whereas brain opioid systems are important in the regulation of basal alcohol consumption by rats. [source] Surface-sensitive reflection-mode EXAFS from layered sample systems: the influence of surface and interface roughnessJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2009P. Keil The calculation of reflection-mode grazing-incidence X-ray absorption spectra from single surfaces and (multi-)layered systems is studied here. In particular, the influence of the surface and interface roughness was investigated in detail. Simulations of grazing-incidence reflection-mode EXAFS spectra using a simple Fresnel theory neglecting any effect of roughness are compared with the Névot,Croce model and the elaborated distorted-wave Born approximation which both include surface and interface roughness. Data are presented for clean gold surfaces, where the strong influence of the surface roughness on the resulting spectra is demonstrated. Furthermore, in the case of layered systems, the influence of both the outer (air or vacuum side) surface roughness and the inner interface roughness on the reflection-mode EXAFS spectra is evaluated. The practical consequences of the observed correlations are discussed, and a quantitative data analysis of a copper sample that was oxidized in ambient air for several months is shown, including the evaluation of specular reflectivity profiles at fixed energy. [source] Shaking alone, without concurrent aeration, affects the growth characteristics of Escherichia coliLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2007M.A. Juergensmeyer Abstract Aims:, This study investigated the effects of linear vibration on cultures grown in both hard- and soft-sided containers to determine whether vibration alone affected the growth rate. Methods and Results:, Cultures of Escherichia coli were exposed to vibrational acceleration with and without access to additional oxygen. Vibrated cultures grown in hard-sided containers exited lag phase earlier and had a higher final yield than identical unshaken cultures, whether or not the cultures had access to ambient air. Cultures grown in soft-sided containers showed no response to vibration. Conclusions:, Vibration in hard-sided containers decreases the length of the lag phase and increases final OD in E. coli, with or without increased oxygenation. Increased mixing and improved suspension, which result from vibration of cultures in hard-sided containers, are the most likely physical mechanisms for the more favorable culture conditions. Significance and Impact of the Study:, This paper demonstrates that growth enhancement of shaken cultures is a function of the rigidity of the vessel even without aeration of the medium. [source] Anisotropic Motion of Electroactive Papers Coated with PEDOT/PSSMACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2010Jian Zhou Abstract We report on an anisotropic actuation of electroactive papers with a PEDOT/PSS coating in ambient air. PEDOT/PSS-coated papers were prepared by wetting Manila papers with a concentrated PEDOT/PSS aqueous dispersion and subsequent drying. The electroactive papers displayed a contractile stress when an external voltage was applied, the magnitude and direction of the stress depending on the relative orientation of paper fibers and the loading direction of the coating. We also demonstrated that a butterfly-like reversible bending motion of the PEDOT/PSS coated paper occurred when the voltage switching between on and off. [source] The allergen Bet v 1 in fractions of ambient air deviates from birch pollen countsALLERGY, Issue 7 2010J. T. M. Buters To cite this article: Buters JTM, Weichenmeier I, Ochs S, Pusch G, Kreyling W, Boere AJF, Schober W, Behrendt H. The allergen Bet v 1 in fractions of ambient air deviates from birch pollen counts. Allergy 2010; 65: 850,858. Abstract Background:, Proof is lacking that pollen count is representative for allergen exposure, also because allergens were found in nonpollen-bearing fractions of ambient air. Objective:, We monitored simultaneously birch pollen and the major birch pollen allergen Bet v 1 in different size fractions of ambient air from 2004 till 2007 in Munich, Germany. Methods:, Air was sampled with a ChemVol® high-volume cascade impactor equipped with stages for particulate matter (PM)>10 ,m, 10 ,m>PM>2.5 ,m, and 2.5 ,m>PM>0.12 ,m. Allergen was determined with a Bet v 1-specific ELISA. Pollen count was assessed with a Burkard pollen trap. We also measured the development of allergen in pollen during ripening. Results:, About 93 ± 3% of Bet v 1 was found in the PM,>,10 ,m fraction, the fraction containing birch pollen. We did not measure any Bet v 1 in 2.5 ,m,>,PM,>,0.12 ,m. Either in Munich no allergen was in this fraction or the allergen was absorbed to diesel soot particles that also deposit in this fraction. Pollen released 115% more Bet v 1 in 2007 than in 2004. Also within 1 year, the release of allergen from the same amount of pollen varied more than 10-fold between different days. This difference was explained by a rapidly increasing expression of Bet v 1 in pollen in the week just before pollination. Depending on the day the pollen is released during ripening, its potency varies. Conclusion:, In general, pollen count and allergen in ambient air follow the same temporal trends. However, because a 10-fold difference can exist in allergen potency of birch pollen, symptoms might be difficult to correlate with pollen counts, but perhaps better with allergen exposure. [source] Comparison of plume structures of carbon dioxide emitted from different mosquito trapsMEDICAL AND VETERINARY ENTOMOLOGY, Issue 1 2006Miriam F. Cooperband Abstract., A large field wind tunnel was used to compare four types of CO2 -baited mosquito traps. This study compared the plume structure and concentration of CO2 emitted by each trap, flow of suction into the trapping systems, flow of CO2 being released, trap shape and configuration, differences in visual appearance, and differences in temperature and humidity of emissions at the source of CO2 compared to ambient air. The structure of the CO2 plumes emitted by each trap differed considerably. All four plumes were turbulent, causing the concentration of CO2 within several metres of the source to attenuate to between 375 and 875 p.p.m. The Encephalitis Virus Surveillance (EVS) trap emitted concentrations of CO2 exceeding 20 000 p.p.m., the detection limits of our equipment, whereas the Mosquito Magnet® Freedom (MMF), Mosquito Magnet® Liberty (MML) and Mosquito Magnet® X (MMX) traps released CO2 at peaks of about 3500, 7200 and 8700 p.p.m., respectively. The MMX trap produced the greatest air velocity at both the suction inlet and CO2 outlet, followed by the MMF, MML and the EVS traps, respectively. [source] Synthesis and stability of iron nanoparticles for lunar environment studiesMETEORITICS & PLANETARY SCIENCE, Issue 6 2010Ching-Cheh HUNG However, unlike the true lunar dust, today's simulants do not contain nanophase iron. Two different processes have been developed to fabricate nanophase iron to be used as part of a lunar dust simulant. (1) The first is to sequentially treat a mixture of ferric chloride, fluorinated carbon, and soda lime glass beads at about 300 °C in nitrogen, at room temperature in air, and then at 1050 °C in nitrogen. The product includes glass beads that are gray in color, can be attracted by a magnet, and contains ,-iron nanoparticles (which seem to slowly lose their lattice structure in ambient air during a period of 12 months). This product may have some similarity to the lunar glassy agglutinate, which contains FeO. (2) The second is to heat a mixture of carbon black and a lunar simulant (a mixed metal oxide that includes iron oxide) at 1050 °C in nitrogen. This process simulates lunar dust reactions with the carbon in a micrometeorite at the time of impact. The product contains a chemically modified simulant that can be attracted by a magnet and has a surface layer whose iron concentration increased during the reaction. The iron was found to be ,-iron and Fe3O4 nanoparticles, which appear to grow after the fabrication process. This growth became undetectable after 6 months of ambient air storage, but may last for several years or longer. [source] Detection of pollen grains in multifocal optical microscopy images of air samplesMICROSCOPY RESEARCH AND TECHNIQUE, Issue 6 2009Sander H. Landsmeer Abstract Pollen is a major cause of allergy and monitoring pollen in the air is relevant for diagnostic purposes, development of pollen forecasts, and for biomedical and biological researches. Since counting airborne pollen is a time-consuming task and requires specialized personnel, an automated pollen counting system is desirable. In this article, we present a method for detecting pollen in multifocal optical microscopy images of air samples collected by a Burkard pollen sampler, as a first step in an automated pollen counting procedure. Both color and shape information was used to discriminate pollen grains from other airborne material in the images, such as fungal spores and dirt. A training set of 44 images from successive focal planes (stacks) was used to train the system in recognizing pollen color and for optimization. The performance of the system has been evaluated using a separate set of 17 image stacks containing 65 pollen grains, of which 86% was detected. The obtained precision of 61% can still be increased in the next step of classifying the different pollen in such a counting system. These results show that the detection of pollen is feasible in images from a pollen sampler collecting ambient air. This first step in automated pollen detection may form a reliable basis for an automated pollen counting system. Microsc. Res. Tech., 2009. © 2009 Wiley-Liss, Inc. [source] Endothelial nitric oxide synthase and nitric oxide regulate endothelial tissue factor expression in vivo in the sickle transgenic mouse,AMERICAN JOURNAL OF HEMATOLOGY, Issue 1 2010Anna Solovey Activation of the coagulation system is a characteristic feature of sickle cell anemia, which also includes clinical thrombosis. The sickle transgenic mouse abnormally expresses tissue factor (TF) on the pulmonary vein endothelium. Knowing that this aberrancy is stimulated by inflammation, we sought to determine whether nitric oxide (NO) contributes to regulation of endothelial TF expression in the sickle mouse model. We used the NY1DD sickle mouse, which exhibits a low-TF to high-TF phenotype switch on exposure to hypoxia/reoxygenation. Manipulations of NO biology, such as breathing NO or addition of arginine or L -NAME (N -nitro- L -arginine-methyl-ester) to the diet, caused significant modulations of TF expression. This was also seen in hBERK1 sickle mice, which have a different genetic background and already have high-TF even at ambient air. Study of NY1DD animals bred to overexpress endothelial nitric oxide synthase (eNOS; eNOS-Tg) or to have an eNOS knockout state (one eNOS,/, animal and several eNOS+/, animals) demonstrated that eNOS modulates endothelial TF expression in vivo by down-regulating it. Thus, the biodeficiency of NO characteristic of patients with sickle cell anemia may heighten risk for activation of the coagulation system. Am. J. Hematol., 2010. © 2009 Wiley-Liss, Inc. [source] Field evaluation of vaporised ethyl formate and carbon dioxide for fumigation of stored wheatPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 4 2010Greg Dojchinov Abstract BACKGROUND: VapormateÔ is a cylinderised non-flammable mixture of ethyl formate (16.7% by weight) and carbon dioxide (CO2) that has been developed as a rapid fumigant of stored grain. Four field trials were undertaken on wheat in 50 t farm silos to demonstrate the feasibility of dynamic application. To assess treatment efficacy, each trial tested mixed stages of Rhyzopertha dominica F. (>11 000), Tribolium castaneum (Herbst.) (>1500) and Sitophilus oryzae (L.) (>13 000) in mesh cages positioned through the centre of the grain bulk and on the grain surface. Ethyl formate and CO2 concentrations were measured in the silo during fumigation and in ambient air outside the 6 m fumigation zone. Application rates of 420, 660 and 940 g m,3 of ethyl formate/CO2 formulation and exposure times of 24, 3 and 72 h, respectively, were examined using wheat of 10.4,11.7% moisture content and grain temperatures between 2 and 32 °C. RESULTS: All life stages of R. dominica and T. castaneum were fully controlled under all conditions tested, and mortality of all life stages of S. oryzae was greater than 98%. CONCLUSION: Dynamic application of vaporised ethyl formate and CO2 to 50 t silos proved safe to operators and rapidly effective against stored-grain insects on cold to warm grain. Copyright © 2009 CSIRO, Australia. Published by John Wiley & Sons, Ltd [source] Development of graphene layers by reduction of graphite fluoride C2F surfacePHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11-12 2009A. V. Okotrub Abstract We studied a possibility of reduction of the surface of graphite fluoride obtained by fluorination of highly oriented pyrolytic graphite (HOPG) by a gaseous mixture of BrF3 and Br2. X-ray diffraction (XRD) revealed a layered structure of the fluorinated product being a second-stage intercalate due to a presence of bromine molecules between the fluorinated graphite layers. Scanning tunneling microscopy and spectroscopy showed that the "old" surface of graphite fluoride (exposed to the ambient air) has the graphite-like structure, while the fresh cleaved surface is non-conductive. Therefore, the outer layers of graphite fluoride can be reduced by water present in the laboratory atmosphere. The sample was treated by H2O vapor to confirm that. The reduction was controlled by Raman spectroscopy using intensity of the 1360 and 1580,cm,1 bands. The energy dependent photoelectron spectroscopy was used for estimation of thickness of the reduction layer, which was found, does not exceed 2,3 graphite layers. The obtained results indicate the possibility of synthesis of graphene layers on dielectric fluorinated graphite matrix. [source] Stomatal responses to humidity and temperature in darknessPLANT CELL & ENVIRONMENT, Issue 7 2010KEITH A. MOTT ABSTRACT Stomatal responses to leaf temperature (Tl) and to the mole fractions of water vapour in the ambient air (wa) and the leaf intercellular air spaces (wi) were determined in darkness to remove the potential effects of changes in photosynthesis and intercellular CO2 concentration. Both the steady-state and kinetic responses of stomatal conductance (gs) to wa in darkness were found to be indistinguishable from those in the light. gs showed a steep response to the difference (,w) between wa and wi when wa was varied. The response was much less steep when wi was varied. Although stomatal apertures responded steeply to Tl when ,w was held constant at 17 mmol mol,1, the response was much less steep when ,w was held constant at about zero. Similar results were obtained in the light for ,w = 15 mmol mol,1 and ,w , 0 mmol mol,1. These results are discussed in the context of mechanisms for the stomatal response to humidity. [source] The effect of gravity on surface temperatures of plant leavesPLANT CELL & ENVIRONMENT, Issue 4 2003Y. KITAYA ABSTRACT A fundamental study was conducted to develop a facility having an adequate air circulation system for growing healthy plants over a long-term under microgravity conditions in space. To clarify the effects of gravity on heat exchange between plant leaves and the ambient air, surface temperatures of sweet potato and barley leaves and replica leaves made of wet paper and copper were evaluated at gravity levels of 0.01, 1.0, 1.5 and 2.0 g for 20 s each during parabolic aeroplane flights. Thermal images were captured using infrared thermography at an air temperature of 26 °C, a relative humidity of 18% and an irradiance of 260 W m,2. Mean leaf temperatures increased by 0.9,1.0 °C with decreasing gravity levels from 1.0 to 0.01 g and decreased by 0.5 °C with increasing gravity levels from 1.0 to 2.0 g. The increase in leaf temperatures was at most 1.9 °C for sweet potato leaves over 20 s as gravity decreased from 1.0 to 0.01 g. The boundary layer conductance to sensible heat exchange decreased by 5% when the gravity decreased from 1.0 to 0.01 g at the air velocity of 0.2 m s,1. The decrease in the boundary layer conductance with decrease in the gravity levels was more significant in a lower air velocity. Heat exchange between leaves and the ambient air was more retarded at lower gravity levels because of less sensible and latent heat transfers with less heat convection. [source] | |||||||||||||||||||||||||