2,081 research outputs found
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Catalyzed Gasoline Particulate Filters Reduce Secondary Organic Aerosol Production from Gasoline Direct Injection Vehicles
The
effects of photochemical aging on exhaust emissions from two
light-duty vehicles with gasoline direct injection (GDI) engines equipped
with and without catalyzed gasoline particle filters (GPFs) were investigated
using a mobile environmental chamber. Both vehicles with and without
the GPFs were exercised over the LA92 drive cycle using a chassis
dynamometer. Diluted exhaust emissions from the entire LA92 cycle
were introduced to the mobile chamber and subsequently photochemically
reacted. It was found that the addition of catalyzed GPFs will significantly
reduce tailpipe particulate emissions and also provide benefits in
gaseous emissions, including nonmethane hydrocarbons (NMHC). Tailpipe
emissions composition showed important changes with the use of GPFs
by practically eliminating black carbon and increasing the fractional
contribution of organic mass. Production of secondary organic aerosol
(SOA) was reduced with GPF addition, but was also dependent on engine
design which determined the amount of SOA precursors at the tailpipe.
Our findings indicate that SOA production from GDI vehicles will be
reduced with the application of catalyzed GPFs through the mitigation
of reactive hydrocarbon precursors
Inactivation of Aurora kinases and Cyclin-dependent kinases 4/6 allows cancers to adopt an endoreplication and form polyploid/polyaneuploid giant cancer cells (PGCCs/PACCs) that resist antimitotic drugs
View full abstracthttps://openworks.mdanderson.org/leading-edge/1044/thumbnail.jp
The Effects of Danofloxacin and Tilmicosin on Neutrophil Function and Lung Consolidation in Beef Heifer Calves with Induced Pasteurella (Mannheimia) haemolytica Pneumonia
Pneumonia caused by Pasteurella (Mannheimia) haemolytica was induced in weaned beef heifer calves, approximately 6 months of age. Calves were treated at 20 h after challenge with therapeutic doses of danofloxacin or tilmicosin. Peripheral blood neutrophils were collected at 3, 24 and 48 h after treatment. The ex vivo effects on neutrophil function, neutrophil apoptosis, and hematological parameters were examined, as was the effect on percentage lung consolidation. Neutrophil function assays included random migration under agarose, cytochrome C reduction, iodination, Staphylococcus aureus ingestion, chemotaxis, and antibody-dependent and antibody-independent cell-mediated cytotoxicity. Apoptosis was determined using a cell death detection kit. Killing was performed at 72 h after treatment. Statistical comparisons were made among the three groups of challenged–treated animals: saline, danofloxacin, and tilmicosin. Comparisons were also made between nonchallenged nontreated animals (NCH) and challenged saline-treated animals. There were no significant differences for any of the neutrophil function assays or neutrophil apoptosis among the challenged–treated groups. This suggests that danofloxacin and tilmicosin have no clinically significant effects on neutrophil function or apoptosis. There were also no significant differences in percentage lung consolidation among the challenged–treated groups. Significant differences were found between the NCH calves and the challenged saline-treated calves in several neutrophil assays, which were attributed to effects of P. haemolyticainfectio
Differently anchored influenza hemagglutinin mutants display distinct interaction dynamics with mutual rafts
Lipid rafts play important roles in cellular functions through concentrating or sequestering membrane proteins. This requires proteins to differ in the stability of their interactions with lipid rafts. However, knowledge of the dynamics of membrane protein–raft interactions is lacking. We employed FRAP to measure in live cells the lateral diffusion of influenza hemagglutinin (HA) proteins that differ in raft association. This approach can detect weak interactions with rafts not detectable by biochemical methods. Wild-type (wt) HA and glycosylphosphatidylinositol (GPI)-anchored HA (BHA-PI) diffused slower than a nonraft HA mutant, but became equal to the latter after cholesterol depletion. When antigenically distinct BHA-PI and wt HA were coexpressed, aggregation of BHA-PI into immobile patches reduced wt HA diffusion rate, suggesting transient interactions with BHA-PI raft patches. Conversely, patching wt HA reduced the mobile fraction of BHA-PI, indicating stable interactions with wt HA patches. Thus, the anchoring mode determines protein–raft interaction dynamics. GPI-anchored and transmembrane proteins can share the same rafts, and different proteins can interact stably or transiently with the same raft domains
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Irrigation in Support of Research Project: Seismic Absorption and Modulus Measurement
The irrigation site located at the University of Arizona Maricopa Agricultural Center was designed to support controlled irrigation through the use of evenly spaced drip tubing under a heavy black plastic tarp. Soil solution samplers (lysimeters) are placed at specific locations to collect water from 1.5 meters, 3.0 meters and 10 meters from the soil surface. Suction provided by a vacuum pump was applied to the lysimeters for three hours prior to collection. After this time, the soil solution, if any was collected and placed into 20 ml HDPE scintillation vials and stored at -15 C for later analysis. These samples were analyzed for pH with a Ross Sure Flow Combination Electrode. Electrical conductivity for each sample was measured with the use of an Accumet Conductivity Cell. Both electrodes were connected to an Accumet Model 50 pH/ion/conductivity meter. High Performance Liquid Chromatography was employed in an attempt to determine the amount of Biosurfactant present in each sample. Our HPLC equipment includes a 5mm x 15mm CIS chromatography column, Waters 2487 detector, 510 pump, and WISP 710 Auto Injector. Millennium software was used to integrate data from these analyses
Results of the 2016 Indianapolis Biodiversity Survey, Marion County, Indiana
Surprising biodiversity can be found in cities, but urban habitats are understudied. We report on a bioblitz conducted primarily within a 24-hr period on September 16 and 17, 2016 in Indianapolis, Indiana, USA. The event focused on stretches of three waterways and their associated riparian habitat: Fall Creek (20.6 ha; 51 acres), Pleasant Run (23.5 ha; 58 acres), and Pogue’s Run (27.1 ha; 67 acres). Over 75 scientists, naturalists, students, and citizen volunteers comprised 14 different taxonomic teams. Five hundred ninety taxa were documented despite the rainy conditions. A brief summary of the methods and findings are presented here. Detailed maps of survey locations and inventory results are available on the Indiana Academy of Science website (https://www.indianaacademyofscience.org/)
Role of Stone-Wales Defects on the Interfacial Interactions Among Graphene, Carbon Nanotubes, and Nylon 6: A First-Principles Study
We investigate computationally the role of Stone-Wales (SW) defects on the interfacial interactions among graphene, carbon nanotubes (CNTs), and Nylon 6 using density functional theory (DFT) and the empirical force-field. Our first-principles DFT calculations were performed using the Quantum ESPRESSO electronic structure code with the highly accurate van der Waals functional (vdW-DF2). Both pristine and SW-defected carbon nanomaterials were investigated. The computed results show that the presence of SW defects on CNTs weakens the CNT-graphene interactions. Our result that CNT-graphene interaction is much stronger than CNT-CNT interaction indicates that graphene would be able to promote the dispersion of CNTs in the polymer matrix. Our results demonstrate that carbon nanomaterials form stable complexes with Nylon 6 and that the van der Waals interactions, as revealed by the electronic charge density difference maps, play a key stabilizing role on the interfacial interactions among graphene, CNTs, and Nylon 6. Using the density of states calculations, we observed that the bandgaps of graphene and CNTs were not significantly modified due to their interactions with Nylon 6. The Young’s moduli of complexes were found to be the averages of the moduli of their individual constituents. Published by AIP Publishing. https://doi.org/10.1063/1.503208
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