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- Odor (4)
- Volatile organic compounds (4)
- Cattle (3)
- Gas chromatography (3)
- Land and Water Resources Engineering (3)
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- Manure (3)
- Volatile fatty acids (3)
- Air quality (2)
- Air sampling (2)
- Ammonia (2)
- Area source (2)
- Carbofuran (2)
- Continuous emissions monitoring (2)
- Daphnia magna (2)
- Dynamic flow through surface chamber (2)
- Flux (2)
- Hedonic tone (2)
- Hydrogen sulfide (2)
- Intensity (2)
- Multiple stressors (2)
- Open dirt cattle feedlots (2)
- Permeation tubes (2)
- Precision Agriculture (2)
- Remote sensing (2)
- Soil moisture (2)
- Solid phase microextraction (2)
- Spectrophotometry (2)
- Standard gas generation (2)
- Suspended solids (2)
- Abundance (1)
Articles 1 - 29 of 29
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Estimations Of Ammonia And Hydrogen Sulfide Fluxes From Cattle Feedlot Surfaces In Texas High Plains, Bok-Haeng Baek, Jacek A. Koziel, Jarett P. Spinhirne, David B. Parker, Nolan A. Cole
Estimations Of Ammonia And Hydrogen Sulfide Fluxes From Cattle Feedlot Surfaces In Texas High Plains, Bok-Haeng Baek, Jacek A. Koziel, Jarett P. Spinhirne, David B. Parker, Nolan A. Cole
Jacek A. Koziel
A dynamic flow-through chamber system and continuous analyzers were used for on-site measurements of ammonia-nitrogen (NH 3 -N) and hydrogen sulfide-sulfur (H 2 S-S) fluxes from commercial feedlot surfaces in northwestern Texas during two week period in the summer of 2002. Ambient air and air inside chamber temperatures, and manure pack temperature were measured continuously. Manure pack moisture content, pH, and TKN were measured daily to characterize its correlation with NH 3 -N fluxes. The preliminary average NH 3 -N flux from the feedlot surface for the entire measurement period was 1,669 ± 1,212 NH 3 -N µ g/m 2 …
Generation And Calibration Of Standard Gas Mixtures For Volatile Fatty Acids Using Permeation Tubes And Solid Phase Microextraction, Jacek A. Koziel, Jarett P. Spinhirne
Generation And Calibration Of Standard Gas Mixtures For Volatile Fatty Acids Using Permeation Tubes And Solid Phase Microextraction, Jacek A. Koziel, Jarett P. Spinhirne
Jacek A. Koziel
Volatile fatty acids (VFAs) are major components of odors associated with agricultural operations and livestock housing, solid waste processing and disposal, and industrial and municipal wastewater collection and treatment systems. Emissions estimation and assessment of odor control methods depend on reliable air sampling and analysis methods for VFAs. The objective of this research was to develop and test a method for continuous and reliable generation of standard gas mixtures for VFAs based on permeation tubes. Standard gas mixtures for acetic, propionic, isobutyric, butyric, isovaleric, valeric, and hexanoic acids were generated with permeation tubes and monitored for a 100-day period. The …
Sensitization Of Staphylococcus Aureus And Escherichia Coli To Antibiotics By The Sesquiterpenoids Nerolidol, Farnesol, Bisabolol, And Apritone, Byron F. Brehm-Stecher, Eric A. Johnson
Sensitization Of Staphylococcus Aureus And Escherichia Coli To Antibiotics By The Sesquiterpenoids Nerolidol, Farnesol, Bisabolol, And Apritone, Byron F. Brehm-Stecher, Eric A. Johnson
Byron F. Brehm-Stecher
The sesquiterpenoids nerolidol, farnesol, bisabolol, and apritone were investigated for their abilities to enhance bacterial permeability and susceptibility to exogenous antimicrobial compounds. Initially, it was observed by flow cytometry that these sesquiterpenoids promoted the intracellular accumulation of the membrane-impermeant nucleic acid stain ethidium bromide by live cells of Lactobacillus fermentum, suggesting that enhanced permeability resulted from disruption of the cytoplasmic membrane. The ability of these sesquiterpenoids to increase bacterial susceptibility to a number of clinically important antibiotics was then investigated. In disk diffusion assays, treatment with low concentrations (0.5 to 2 mM) of nerolidol, bisabolol, or apritone enhanced the susceptibility …
Does Landscape Diversity Slow The Spread Of Rotation-Resistant Western Corn Rootworm (Coleoptera: Chrysomelidae)?, D. W. Onstad, D. W. Crwoder, S. A. Isard, E. Levine, J. L. Spencer, Matthew E. O'Neal, S. T. Ratcliffe, M. E. Gray, L. W. Bledsoe, C. D. Di Fonzo, J. B. Eisley, C. R. Edwards
Does Landscape Diversity Slow The Spread Of Rotation-Resistant Western Corn Rootworm (Coleoptera: Chrysomelidae)?, D. W. Onstad, D. W. Crwoder, S. A. Isard, E. Levine, J. L. Spencer, Matthew E. O'Neal, S. T. Ratcliffe, M. E. Gray, L. W. Bledsoe, C. D. Di Fonzo, J. B. Eisley, C. R. Edwards
Matthew E. O'Neal
A behavioral change in some western corn rootworm (Diabrotica virgifera virgifera LeConte) populations is threatening the effectiveness of crop rotation, a successful management strategy for controlling this pest. We created a set of simple meteorologic and behavioral models that can be used to predict the spread of the beetle infesting soybean (Glycine max (L.)) throughout the midwestern United States. We used data collected in Illinois, IN, MI, and Ohio to create maps of observations to evaluate the model. We displayed data on the maps using detection thresholds for western corn rootworm in soybean fields of 10 or 20 beetles per …
Ammonia Concentrations In Poultry Broiler Production Units Treated With Liquid Alum, K. A. Armstrong, Robert T. Burns, F. R. Walker, L. R. Wilhelm, D. Raj Raman
Ammonia Concentrations In Poultry Broiler Production Units Treated With Liquid Alum, K. A. Armstrong, Robert T. Burns, F. R. Walker, L. R. Wilhelm, D. Raj Raman
D. Raj Raman
High ammonia concentrations in commercial broiler production houses can result in poor bird performance, lower feed conversion ratios, and higher mortalities. Growers have traditionally controlled in-house ammonia levels by increasing ventilation. During cold weather, increased ventilation rates result in higher heating energy requirements. Granular alum (aluminum sulfate, Al2(SO4)3 · 14H2O) has been successfully used as a litter amendment to reduce ammonia volatilization from litter inside broiler production houses. In this study, liquid aluminum sulfate was investigated as a litter amendment for ammonia suppression in four commercial poultry-broiler units. This project investigates four treatment levels of liquid alum in four adjacent …
Release And Transport Of Bacteria And Nutrients From Livestock Manure Applied To Pastureland, Michelle L. Soupir
Release And Transport Of Bacteria And Nutrients From Livestock Manure Applied To Pastureland, Michelle L. Soupir
Michelle L. Soupir
Transport of fecal bacteria and nutrients from point and nonpoint sources to surface water bodies is of significant concern in Virginia and the United States. In Virginia, 4,320 river miles are impaired for one or more beneficial use and 72% of the streams are impaired due to pathogen indicators (VDEQ, 2002). Land applications of manure from confined animal systems and by direct deposit by grazing animals are both major sources of fecal bacteria and nutrients in runoff. Therefore, an understanding of the overland transport mechanisms for fecal bacteria and nutrients is very important for the development of best management practices …
Properties Of Corn Masa Processing Byproducts, Kurt A. Rosentrater
Properties Of Corn Masa Processing Byproducts, Kurt A. Rosentrater
Kurt A. Rosentrater
The production of corn masa-based products in the U.S. has been increasing over the last several years, and as a result, so has the quantity of waste materials generated from this industry. These byproduct materials may have potential for value-added processing and utilization, which are options that hold the promise of economic benefits for masa processors and decreased potential pollution for the environment. Fundamental to any byproduct development, however, is a full characterization of the processing residue, because physical and nutritional properties are necessary for the proper design of processing operations and applications. Vital physical properties include moisture content, water …
Using Efficient Software Architecture For Computer-Based Training Programs To Promote International Development, Kurt A. Rosentrater, Kari Pape Rosentrater
Using Efficient Software Architecture For Computer-Based Training Programs To Promote International Development, Kurt A. Rosentrater, Kari Pape Rosentrater
Kurt A. Rosentrater
Many international agencies offer volunteer services to improve agricultural knowledge and infrastructure in developing countries. Although effective, these efforts are severely constrained by limited funding and personnel, and can only address a fraction of current global educational needs. Computer-based training programs, either in the form of CD-ROM-based or Internet-based incarnations, hold the promise of removing many of the obstacles that currently confront international volunteer efforts. The art of web programming has drastically accelerated in recent years, both in terms of capacity as well as complexity. One reason for this is that advanced software has been developed to simplify and speed …
Assessment Of Moisture Control And Additives For Odor Reduction From Open-Lot Feedyard Surfaces, Jocelyn D. Buchanan, David B. Parker, Marty B. Rhoades, Jacek A. Koziel, William J. Rogers
Assessment Of Moisture Control And Additives For Odor Reduction From Open-Lot Feedyard Surfaces, Jocelyn D. Buchanan, David B. Parker, Marty B. Rhoades, Jacek A. Koziel, William J. Rogers
Jacek A. Koziel
Amendments for reducing odor from open-lot beef cattle feedyards were evaluated in the laboratory. Manure was placed in small Tupperware® containers. Water and amendments were added to the manure surface and the containers were attached to a vacuum pump that continually passed 2.5 L/min of carbon-filtered air over the surface. Eleven different amendments were tested, at two different concentrations, in a series of five experiments. Odor samples were collected 3 times during a 10-day period in each experiment and were analyzed by trained panelists for detection threshold (DT), intensity and hedonic tone. None of the amendments showed any overwhelming evidence …
Background Odors In Tedlar® Bags Used For Cafo Odor Sampling, David B. Parker, Marty B. Rhoades, Jacek A. Koziel, Jarett Spinhirne
Background Odors In Tedlar® Bags Used For Cafo Odor Sampling, David B. Parker, Marty B. Rhoades, Jacek A. Koziel, Jarett Spinhirne
Jacek A. Koziel
Tedlar® film is manufactured in a wet solvent process and continues to emit organic compounds after manufacturing. Tedlar® bags are used for odor sampling at concentrated animal feeding operations (CAFOs). Odor regulations for CAFOs vary widely, but maximum detection thresholds (DTs) of 2 to 15 have been proposed downwind of feeding operations. Results at the WTAMU Olfactometry Laboratory have shown that both commercially available Tedlar® bags and homemade Tedlar® bags have a detectable background odor (DTs of 20 to 60 typical) even following standard protocols for purging. Purging the bags before sampling was not effective in reducing DTs to acceptable …
Estimation Of Ammonia And Hydrogen Sulfide Emissions From Cattle Feedlots In Texas, Bok-Haeng Baek, Jacek A. Koziel, Jarett P. Spinhirne, David B. Parker, Nolan A. Cole
Estimation Of Ammonia And Hydrogen Sulfide Emissions From Cattle Feedlots In Texas, Bok-Haeng Baek, Jacek A. Koziel, Jarett P. Spinhirne, David B. Parker, Nolan A. Cole
Jacek A. Koziel
A dynamic flow-through chamber system and continuous analyzers were used for on-site measurements of ammonia-nitrogen (NH 3 -N) and hydrogen sulfide-sulfur (H 2 S-S) fluxes from commercial feedlot surfaces in northwestern Texas during two week period in the summer of 2002. Manure pack moisture content, pH, and TKN were measured daily to characterize its relation with NH 3 -N fluxes. The preliminary average NH 3 -N and H 2 S-S flux from the feedlot surface were 1,669 ± 1,212 NH 3 -N µ g/m 2 /min and 1.884 ± 1.497 H 2 S-S µ g S/m 2 /min. Manure pack …
Soil Moisture Estimation From Remotely Sensed Hyperspectral Data, Amy L. Kaleita, Lei F. Tian, Haibo Yao
Soil Moisture Estimation From Remotely Sensed Hyperspectral Data, Amy L. Kaleita, Lei F. Tian, Haibo Yao
Amy L. Kaleita
A methodology for mapping surface soil moisture content across an agricultural field from optical remote sensing and ground sampling is developed. This study uses both ground-based and remotely sensed spectral measurements of soil reflectance in visible and near-infrared wavelengths and concurrent measurements of volumetric soil moisture within the top 6 cm. After determining appropriate wavelengths for soil moisture estimation from spectral reflectance, a cokriging scheme was used to generate soil moisture maps. Results indicate that combining reflectance and ground measurements can yield more detailed maps of soil moisture than ground measurement alone.
Soil Moisture Estimation From Remotely Sensed Hyperspectral Data, Amy L. Kaleita, Lei Tian, Haibo Yao
Soil Moisture Estimation From Remotely Sensed Hyperspectral Data, Amy L. Kaleita, Lei Tian, Haibo Yao
Amy L. Kaleita
A methodology for mapping surface soil moisture content across an agricultural field from optical remote sensing and ground sampling is developed. This study uses both ground-based and remotely sensed spectral measurements of soil reflectance in visible and near-infrared wavelengths and concurrent measurements of volumetric soil moisture within the top 6 cm. After determining appropriate wavelengths for soil moisture estimation from spectral reflectance, a cokriging scheme was used to generate soil moisture maps. Results indicate that combining reflectance and ground measurements can yield more detailed maps of soil moisture than ground measurement alone.
Modeling Of Sediment Trapping In A Vegetative Filter Accounting For Two-Dimensional Overland Flow, Matthew J. Helmers, Dean E. Eisenhauer, Thomas G. Franti, Michael G. Dosskey
Modeling Of Sediment Trapping In A Vegetative Filter Accounting For Two-Dimensional Overland Flow, Matthew J. Helmers, Dean E. Eisenhauer, Thomas G. Franti, Michael G. Dosskey
Matthew J. Helmers
Vegetative filters (VF) are used to remove sediment and other pollutants from overland flow. When modeling the hydrology of VF it is often assumed that overland flow is planar but our research indicates that it can be two-dimensional with converging and diverging pathways. Our hypothesis is that flow convergence will negatively influence the sediment trapping capability of VF. The objectives were to develop a two-dimensional modeling approach for estimating sediment trapping in VF and to investigate the impact of converging overland flow on sediment trapping by VF. In this study, the performance of a VF that has field-scale flow path …
Development Of A Controller Area Network Based Handheld Data Acquisition System For Identity Preservation, Matthew J. Darr, Jason Kellam Ward, Timothy S. Stombaugh, Michael D. Montross
Development Of A Controller Area Network Based Handheld Data Acquisition System For Identity Preservation, Matthew J. Darr, Jason Kellam Ward, Timothy S. Stombaugh, Michael D. Montross
Matthew J. Darr
The development of a diverse, modular and portable system to accurately measure and record field operations is required to effectively bring identity preservation of crops to all farms and farmers. A demonstration system has been built based on a worldwide standard communications protocol and was evaluated for its ability to efficiently measure a variety of field operations and management practices. The CAN Bus 2.0B communication protocol was used to record GPS location data, ground speed and simulated spraying system data. This data was compiled and stored in a form that was compatible with multiple software programs for the purposes of …
Odor Characterization At Open-Lot Beef Cattle Feedyards Using Triangular Forced Choice Olfactometry, David B. Parker, Marty B. Rhoades, Brent W. Auvermann, Jacek A. Koziel
Odor Characterization At Open-Lot Beef Cattle Feedyards Using Triangular Forced Choice Olfactometry, David B. Parker, Marty B. Rhoades, Brent W. Auvermann, Jacek A. Koziel
Jacek A. Koziel
Odor samples were collected two to four times per month over a one-year period in 2002-2003 at three large open-lot beef cattle feedyards in the Texas panhandle. Samples were collected in 10 L Tedlar bags using a vacuum chamber upwind of the feedyard, downwind of the pens, and downwind of the runoff storage pond. Samples were analyzed in the odor lab for detection threshold (DT) using triangular forced choice olfactometry with trained human odor panelists. Full-strength odor samples were also analyzed for intensity and hedonic tone. Weather data was collected on-site at each of the feedyards for correlation to odor …
Characterization Of Volatile Organic Compounds In Bovine Breath Using Solid-Phase Microextraction And Gas Chromatography-Mass Spectrometry, Jacek A. Koziel, Jarett P. Spinhirne, Norbert K. Chirase
Characterization Of Volatile Organic Compounds In Bovine Breath Using Solid-Phase Microextraction And Gas Chromatography-Mass Spectrometry, Jacek A. Koziel, Jarett P. Spinhirne, Norbert K. Chirase
Jacek A. Koziel
A face mask sampling device, DVB/Carboxen/PDMS 50/30 µ m solid phase microextraction (SPME) fibers, and a gas chromatograph with a mass spectrometer detector (GC-MS) were used for sampling and analysis of volatile organic compounds (VOCs) in bovine breath. Breath of 3 morbid steers with respiratory tract infections and 3 healthy steers were sampled 7 times in 19 days for 15 min at each sampling. A total of 21 VOCs were detected, many of them for the first time in cattle breath. Preliminary statistical analyses using Chi-square Test on the frequency of detection of each VOC in each group was performed. …
Bifunctional Abietadiene Synthase: Mutual Structural Dependence Of The Active Sites For Protonation-Initiated And Ionization-Initiated Cyclizations, Reuben J. Peters, Ora A. Carter, Yan Zhang, Brian W. Matthews, Rodney B. Croteau
Bifunctional Abietadiene Synthase: Mutual Structural Dependence Of The Active Sites For Protonation-Initiated And Ionization-Initiated Cyclizations, Reuben J. Peters, Ora A. Carter, Yan Zhang, Brian W. Matthews, Rodney B. Croteau
Reuben J. Peters
Abietadiene synthase from grand fir catalyzes two sequential, mechanistically distinct cyclizations, of geranylgeranyl diphosphate and of copalyl diphosphate, in the formation of a mixture of abietadiene isomers as the committed step of diterpenoid resin acid biosynthesis. Each reaction is independently conducted at a separate active site residing in what were considered to be structurally distinct domains typical of terpene cyclases. Despite the presence of an unusual 250-residue N-terminal insertional element, a tandem pair of charged residues distal to the insertion was shown to form a functional part of the C-terminal active site. Because abietadiene synthase resembles the ancestral plant terpene …
Rapid Gut Transit Time And Slow Fecal Isoflavone Disappearance Phenotype Are Associated With Greater Genistein Bioavailability In Women, Yan Zheng, Jiang Hu, Patricia A. Murphy, D. Lee Alekel, Warren D. Franke, Suzanne Hendrich
Rapid Gut Transit Time And Slow Fecal Isoflavone Disappearance Phenotype Are Associated With Greater Genistein Bioavailability In Women, Yan Zheng, Jiang Hu, Patricia A. Murphy, D. Lee Alekel, Warren D. Franke, Suzanne Hendrich
Warren D Franke
The bioavailability of soybean isoflavones varies widely among individuals due to many factors, including activities of gut microflora. To characterize factors that affect fecal isoflavone disappearance phenotype and isoflavone bioavailability in women, 35 Asian and 33 Caucasian women, 18-43 y of age, provided fecal samples for anaerobic incubation with isoflavones in vitro at two times 5 mo apart (Phases I and II). Diet, physical activity and health history were investigated at these times. A single dose of soymilk powder [1.2 mg (4.57 micromol) total isoflavone/kg body] was given to all subjects with breakfast in phase II. Daidzein and genistein from …
Linear And Nonlinear Effects Of Habitat Structure On Composition And Abundance In The Macroinvertebrate Community Of A Large River, Timothy W. Stewart, Tammy L. Shumaker, Thomas A. Radzio
Linear And Nonlinear Effects Of Habitat Structure On Composition And Abundance In The Macroinvertebrate Community Of A Large River, Timothy W. Stewart, Tammy L. Shumaker, Thomas A. Radzio
Timothy W. Stewart
We used an experiment and regression analyses to quantify effects of spatial variation in habitat structure abundance on a riverine macroinvertebrate community under winter conditions. Concrete slabs (0.21 m2; n 5 24) with different numbers of stones (mean individual stone surface area 5 6.44 cm2) attached to upper faces were placed in the James River and retrieved after 28 d. Macroinvertebrate abundance and taxonomic richness on slabs were significantly positively related to stone abundance. Total macroinvertebrate abundance and abundance of oligochaetes (Nais spp.), Asiatic clams (Corbicula fluminea), caddisflies (Leptoceridae), riffle beetles (Elmidae) and stoneflies (Strophopteryx sp.) were linearly related to …
Seventy Years Of Forest Change In The Northern Great Lakes Region, Usa, Lisa A. Schulte-Moore, Thomas R. Crow, Dave Cleland
Seventy Years Of Forest Change In The Northern Great Lakes Region, Usa, Lisa A. Schulte-Moore, Thomas R. Crow, Dave Cleland
Lisa A. Schulte Moore
The rates and magnitudes of forest change have important social and economic implications. We address facets of change associated with 20th century recovery of the U.S. Lake States (Michigan, Wisconsin, and Minnesota) forests from the Great Cutover, and discuss ecological and socioeconomic implications for future forest resources.
Overview Of Data And Conceptual Approaches For Derivation Of Quantitative Structure-Activity Relationships For Ecotoxicological Effects Of Organic Chemicals, Steven P. Bradbury, Christine L. Russom, Gerald T. Ankley, T. Wayne Schultz, John D. Walker
Overview Of Data And Conceptual Approaches For Derivation Of Quantitative Structure-Activity Relationships For Ecotoxicological Effects Of Organic Chemicals, Steven P. Bradbury, Christine L. Russom, Gerald T. Ankley, T. Wayne Schultz, John D. Walker
Steven P. Bradbury
The use of quantitative structure–activity relationships (QSARs) in assessing potential toxic effects of organic chemicals on aquatic organisms continues to evolve as computational efficiency and toxicological understanding advance. With the everincreasing production of new chemicals, and the need to optimize resources to assess thousands of existing chemicals in commerce, regulatory agencies have turned to QSARs as essential tools to help prioritize tiered risk assessments when empirical data are not available to evaluate toxicological effects. Progress in designing scientifically credible QSARs is intimately associated with the development of empirically derived databases of well-defined and quantified toxicity endpoints, which are based on …
Qsar Prioritization Of Chemical Inventories For Endocrine Disruptor Testing, Steven P. Bradbury, Patricia Schmeider, Ovanes Mekenyan, Gilman Veith
Qsar Prioritization Of Chemical Inventories For Endocrine Disruptor Testing, Steven P. Bradbury, Patricia Schmeider, Ovanes Mekenyan, Gilman Veith
Steven P. Bradbury
Binding affinity between chemicals and the estrogen receptor (ER) serves as an indicator of the potential to cause endocrine disruption through this receptor-mediated endocrine pathway. Estimating ER-binding affinity is, therefore, one strategic approach to reducing the costs of screening chemicals for potential risks of endocrine disruption. While measuring ER binding with in vitro assays may be the first choice in prioritizing chemicals for additional in vitro or in vivo estrogenicity testing, the time and costs associated with screening thousands of chemicals is prohibitive. Recent advances in 3D modeling of the reactivity of flexible structures make in silico methods for estimating …
An Overview Of The Use Of Quantitative Structure-Activity Relationships For Ranking And Prioritzing Large Chemical Inventories For Environmental Risk Assessments, Steven P. Bradbury, Christine L. Russom, Roger L. Breton, John D. Walker
An Overview Of The Use Of Quantitative Structure-Activity Relationships For Ranking And Prioritzing Large Chemical Inventories For Environmental Risk Assessments, Steven P. Bradbury, Christine L. Russom, Roger L. Breton, John D. Walker
Steven P. Bradbury
Ecological risk assessments for chemical stressors are used to establish linkages between likely exposure concentrations and adverse effects to ecological receptors. At times, it is useful to conduct screening risk assessments to assist in prioritizing or ranking chemicals on the basis of potential hazard and exposure assessment parameters. Ranking of large chemical inventories can provide evidence for focusing research and/or cleanup efforts on specific chemicals of concern. Because of financial and time constraints, data gaps exist, and the risk assessor is left with decisions on which models to use to estimate the parameter of concern. In this review, several methods …
Influence Of Suspended Solids On Acute Toxicity Of Carbofuran To Daphnia Magna: Ii. An Evaluation Of Potential Interactive Mechanisms, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer
Influence Of Suspended Solids On Acute Toxicity Of Carbofuran To Daphnia Magna: Ii. An Evaluation Of Potential Interactive Mechanisms, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer
Steven P. Bradbury
It has been demonstrated that simultaneous exposure of Daphnia magna to suspended solids and a carbamate pesticide potentiates the toxic response to the pesticide. The toxicodynamics between these stressors were investigated to determine possible mechanisms of interaction. Three experimental series were conducted with D. magna to determine: the effect of food availability on carbofuran toxicity; the effect of food availability on jointly administered carbofuran and suspended solids; and changes in the magnitude of effects which can occur with suspended solids of different composition. These experiments demonstrated that both carbofuran toxicity and the joint toxicity of carbofuran and suspended solids to …
Quantitative Structure-Activity Relationship Models For Prediction Of Estrogen Receptor Binding Affinity Of Structurally Diverse Chemicals, Steven P. Bradbury, Patricia K. Schmeider, Gerald Ankley, Ovanes Mekenyan, John D. Walker
Quantitative Structure-Activity Relationship Models For Prediction Of Estrogen Receptor Binding Affinity Of Structurally Diverse Chemicals, Steven P. Bradbury, Patricia K. Schmeider, Gerald Ankley, Ovanes Mekenyan, John D. Walker
Steven P. Bradbury
The demonstrated ability of a variety of structurally diverse chemicals to bind to the estrogen receptor has raised the concern that chemicals in the environment may be causing adverse effects through interference with nuclear receptor pathways. Many structure–activity relationship models have been developed to predict chemical binding to the estrogen receptor as an indication of potential estrogenicity. Models based on either two-dimensional or three-dimensional molecular descriptions that have been used to predict potential for binding to the estrogen receptor are the subject of the current review. The utility of such approaches to predict binding potential of diverse chemical structures in …
Influence Of Suspended Solids On Acute Toxicity Of Carbofuran To Daphnia Magna: I. Interactive Effects, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer
Influence Of Suspended Solids On Acute Toxicity Of Carbofuran To Daphnia Magna: I. Interactive Effects, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer
Steven P. Bradbury
This study explored the effects on Daphnia magna from exposure to the pesticide carbofuran in combination with stress from suspended solids exposure. Our objective was to assess whether suspended solids affects the toxicodynamic response of D. magna to carbofuran. A series of laboratory experiments was performed where animals were exposed to carbofuran concentrations ranging from 0 to 160 mg/l in combination with suspended solids concentrations ranging from 0 to 10,000 mg/l. In the absence of suspended solids, effects of carbofuran were dose dependent and resulted in an EC(sub)50 of 92 mg/l. Exposure to suspended solids, up to extreme levels that …
Characterizing Volatile Fatty Acids And Other Gases In A Rumen Closed In Vitro Fermentation System Using Solid Phase Microextraction, Jarett P. Spinhirne, Jacek A. Koziel, Norbert K. Chirase
Characterizing Volatile Fatty Acids And Other Gases In A Rumen Closed In Vitro Fermentation System Using Solid Phase Microextraction, Jarett P. Spinhirne, Jacek A. Koziel, Norbert K. Chirase
Jacek A. Koziel
A new method for rapid sampling and qualitative characterization of the headspace gases of closed in vitro cultures using solid phase microextraction (SPME) was evaluated for ruminal fluid and ruminal fluid with feed containing a feed additive. Gas sample collection was achieved by exposing a DVB/Carboxen/PDMS 50/30 .m SPME fiber to the headspace of cultures for 1 min every hour. This was followed by immediate analysis on a GC–MS and then reuse of the SPME fiber. Acetic, propionic, isobutyric, butyric, isovaleric, valeric, and hexanoic acids and toluene, dimethyl disulfide, and pentadecane were identified in the headspace. SPME technology facilitated rapid …
Generation And Calibration Of Standard Gas Mixtures For Volatile Fatty Acids Using Permeation Tubes And Solid-Phase Microextraction, Jacek A. Koziel, Jarett P. Spinhirne
Generation And Calibration Of Standard Gas Mixtures For Volatile Fatty Acids Using Permeation Tubes And Solid-Phase Microextraction, Jacek A. Koziel, Jarett P. Spinhirne
Jacek A. Koziel
Volatile fatty acids (VFAs) are major components of odors associated with agricultural operations and livestock housing, solid waste processing and disposal, industrial and municipal wastewater collection, and treatment systems. Emission estimation and assessment of odor control methods depend on reliable air sampling and analysis methods for VFAs. The objective of this research was to develop and test a method for continuous and reliable generation of standard gas mixtures for VFAs based on permeation tubes. Standard gas mixtures for acetic, propionic, isobutyric, butyric, isovaleric, valeric, and hexanoic acids were generated with permeation tubes and monitored for a 100-day period. The gravimetric …