Digital Commons Network^™

Epidemiological Characteristics Of Human Herpesvirus-8 Infection In A Large Population Of Antenatal Women In Zambia, W. Klaskala, B. P. Brayfield, C. Kankasa, G. Bhat, J. T. West, C. D. Mitchell, Charles Wood

Nebraska Center for Virology: Faculty Publications

Comprehensive data describing epidemiological characteristics of the human herpesvirus-8 or Kaposi’s sarcoma-associated herpesvirus (HHV-8 or KSHV) infection among pregnant women in a central sub-Saharan Africa are not available. This study determined virus prevalence estimates and the risk factors associated with HHV-8 infection. Cross-sectional, enrollment visit data were analyzed from a prospective cohort study of perinatal transmission of HHV-8 in Lusaka, Zambia. Exposure data were obtained via structured interview, physical examination, medical chart review, and laboratory testing. Among 3,160 antenatal women serologically screened for HHV-8 between September 1998 and October 2000, 40.2% were seropositive. The HHV-8 positive women were more likely …

Compartmentalization Of Hiv-1 In The Central Nervous System: Role Of The Choroid Plexus, Evan J. Burkala, Jun He, John T. West, Charles Wood, Carol K. Petito

Nebraska Center for Virology: Faculty Publications

Objectives: To determine the genetic and phenotypic composition of HIV-1 found in the choroid plexus (CPx) and its relationship to virus in the brain and peripheral lymphoid tissue. Design: Phenotypic and molecular comparisons of HIV-1 found in autopsy brain, CPx, and spleen tissues. Methods: HIV-1 was co-cultured from matched postmortem brain (basal ganglia), CPx, and spleen tissues of AIDS patients with and without HIV-associated encephalitis and dementia. Viral phenotypes were determined by infection of monocyte-derived macrophages, MT-2 or co-receptor-specific cell lines. Viral env and pol sequences were determined from genomic DNA isolated directly from tissues or co-cultures, and phylogenetic comparisons …

Cutting Edge: Cd4+Cd25+ Regulatory T Cells Contribute To Gender Differences In Susceptibility To Experimental Autoimmune Encephalomyelitis, Jay Reddy, Hanspeter Waldner, Xingmin Zhang, Zsolt Illes, Kai W. Wucherpfennig, Raymond A. Sobel, Vijay K. Kuchroo

Jay Reddy Publications

Female B10.S mice are highly resistant to proteolipid protein (PLP) 139–151-induced experimental autoimmune encephalomyelitis (EAE) and depletion of PLP 139–151- reactive CD4+CD25+regulatory T (Treg) cells can slightly increase their EAE susceptibility. Although male B10.S mice are moderately susceptible to EAE, we report that depletion of Treg cells in male B10.S mice before immunization with PLP 139–151 renders them highly susceptible to severe EAE with more CNS neutrophil infiltrates than nondepleted controls. Increased susceptibility is associated with an enhanced PLP 139–151-specific T cell response and greater production of IFN-γ, IL-6, and IL-17. Male CD4+CD25+ effector cells depleted of Treg cells proliferate …

Latency-Related Gene Encoded By Bovine Herpesvirus 1 Promotes Virus Growth And Reactivation From Latency In Tonsils Of Infected Calves, Sandra Perez, Melissa Inman, Alan R. Doster, Clinton J. Jones

School of Veterinary and Biomedical Sciences: Faculty Publications

Infection of calves with bovine herpesvirus 1 (BHV-1) results in transient immunosuppression that may lead to bacterium-induced pneumonia and, occasionally, death. Although sensory neurons in the trigeminal ganglia (TG) are the primary site of BHV-1 latency, viral genomes are detected in the tonsils of latently infected calves. Dexamethasone (DEX) consistently induces reactivation from latency, and viral gene expression is detected in TG and tonsils. In sensory neurons of latently infected calves, the latency-related (LR) gene is abundantly expressed and is required for reactivation from latency. In the present study, we compared the abilities of wild-type (wt) BHV-1 and a strain …

Factors Associated With The Presence Of Coliforms In The Feed And Water Of Feedlot Cattle, Michael W. Sanderson, Jan M. Sargeant, David G. Renter, Dicky Dee Griffin, Robert A. Smith

School of Veterinary and Biomedical Sciences: Faculty Publications

The objective of this study was to investigate coliform counts in feedlot cattle water and feed rations and their associations with management, climate, fecal material, and water Escherichia coli O157 using a cross-sectional study design. Coliform counts were performed on feed samples from 671 pens on 70 feedlots and on water samples from 702 pens on 72 feedlots in four U.S. states collected between May and August 2001. Management and climate factors were obtained by survey and observation. Month of sampling (higher in May and June), presence of corn silage in the ration (negative association), temperature of the feed 1 …

Serologic Survey Of Select Infectious Diseases In Coyotes And Raccoons In Nebraska, Richard Bischof, Douglas G. Rogers

School of Veterinary and Biomedical Sciences: Faculty Publications

To obtain data about select zoonotic and other infectious diseases in free-ranging predators in five ecoregions in Nebraska, sera were collected from 67 coyotes (Canis latrans) and 63 raccoons (Procyon lotor)) from November 2002 through January 2003. For coyotes, antibodies were detected against canine distemper virus (CDV, 61%), Francisella tularensis) (32%), Rickettsia rickettsi) (13%), and flaviviruses (48%). None of the coyote sera had antibodies to Borrelia burgdorferi, Brucella canis), or six serovars of Leptospira interrogans). Because serologic cross-reactivity exists among flaviviruses, 14 sera from flavivirus-positive coyotes were also tested for St. Louis …

A Multilocus Population Genetic Survey Of The Greater Sage-Grouse Across Their Range, S. J. Oyler-Mccance, S.E. Taylor, T. W. Quinn

United States Geological Survey: Staff Publications

The distribution and abundance of the greater sage-grouse (Centrocercus urophasianus) have declined dramatically, and as a result the species has become the focus of conservation efforts. We conducted a range-wide genetic survey of the species which included 46 populations and over 1000 individuals using both mitochondria1 sequence data and data from seven nuclear microsatellites. Nested clade and STRUCTURE analyses revealed that, in general, the greater sage-grouse populations follow an isolation-by-distance model of restricted gene flow. This suggests that movements of the greater sage-grouse are typically among neighboring populations and not across the species, range. This may have important …

Transport Of Chemical And Microbial Compounds From Known Wastewater Discharges: Potential For Use As Indicators Of Human Fecal Contamination, Susan Glassmeyer, Edward Furlong, Dana Kolpin, Jeffrey Cahill, Steven Zaugg, Stephen Werner, Michael Meyer, David Kryak

United States Geological Survey: Staff Publications

The quality of drinking and recreational water is currently (2005) determined using indicator bacteria. However, the culture tests used to analyze for these bacteria require a long time to complete and do not discriminate between human and animal fecal material sources. One complementary approach is to use chemicals found in human wastewater, which would have the advantages of (1) potentially shorter analysis times than the bacterial culture tests and (2) being selected for human-source specificity. At 10 locations, water samples were collected upstream and at two successive points downstream from a waste-waster treatment plant (WWTP); a treated effluent sample was …

West Nile Virus Infection In Farmed American Alligators (Alligator Mississippiensis) In Florida, Elliott R. Jacobson, Pamela E. Ginn, J. Mitchell Troutman, Lisa Farina, Lillian Stark, Kaci Klenk, Kristen L. Burkhalter, Nicholas Komar

United States Department of Agriculture Wildlife Services: Staff Publications

No abstract provided.

Climate Change And Amphibians, P.S. Corn

United States Geological Survey: Staff Publications

Amphibian life histories are exceedingly sensitive to temperature and precipitation, and there is good evidence that recent climate change has already resulted in a shift to breeding earlier in the year for some species. There are also suggestions that the recent increase in the occurrence of El Niño events has caused declines of anurans in Central America and is linked to elevated mortality of amphibian embryos in the northwestern United States. However, evidence linking amphibian declines in Central America to climate relies solely on correlations, and the mechanisms underlying the declines are not understood. Connections between embryo mortality and declines …

An Evaluation Of Weather And Disease As Causes Of Decline In Two Populations Of Boreal Toads, Rick D. Scherer, Erin Muths, Barry R. Noon, Paul Stephen Corn

United States Geological Survey: Staff Publications

Two populations of boreal toads (Bufo boreas) experienced drastic declines in abundance in the late 1990s. Evidence supported the hypothesis of disease (the chytrid fungus, Batrachochytrium dendrobatidis) as the cause of these declines. but other hypotheses had not been evaluated. We used an 11-year capture-recapture data set to evaluate weather and disease as causes of these declines. We developed sets of mathematical models that reflected hypothesized relationships between several weather variables and annual survival rates of adult males in these populations. In addition, models that reflected the possibility that the declines were caused by an introduced fungus …

Amphibian Research And Monitoring Initiative (Armi): A Successful Start To A National Program In The United States, Erin Muths, Robin E. Jung, Larissa L. Bailey, Michael J. Adams, P. Stephen Corn, C. Kenneth Dodd Jr., Gary M. Fellers, Walter J. Sadinski, Cecil R. Schwalbe, Susan C. Walls, Robert N. Fisher, Alisa L. Gallant, William A. Battaglin, D. Earl Green

United States Geological Survey: Staff Publications

Most research to assess amphibian declines has focused on local-scale projects on one or a few species. The Amphibian Research and Monitoring Initiative (ARMI) is a national program in the United States mandated by congressional directive and implemented by the U.S. Department of the Interior (specifically the U.S. Geological Survey, USGS). Program goals are to monitor changes in populations of amphibians across U.S. Department of the Interior lands and to address research questions related to amphibian declines using a hierarchical framework of base-, mid- and apex-level monitoring sites. ARMI is currently monitoring 83 amphibian species (29% of species in the …

Processing Of Yield Map Data, J. L. Ping, Achim R. Dobermann

Department of Agronomy and Horticulture: Faculty Publications

Yield maps reflect systematic and random sources of yield variation as well as numerous errors caused by the harvest and mapping procedures used. A general framework for processing of multi-year yield map data was developed. Steps included (1) raw data screening, (2) standardization, (3) interpolation, (4) classification of multi-year yield maps, (5) post-classification spatial filtering to create spatially contiguous yield classes, and (6) statistical evaluation of classification results. The techniques developed allow more objective mapping of yield zones, which are an important data layer in algorithms for prescribing variable rates of production inputs.

Environmental Factors Affecting Seed Persistence Of Annual Weeds Across The U.S. Corn Belt, Adam S. Davis, John Cardina, Frank Forcella, Gregg A. Johnson, George Kegode, John L. Lindquist, Edward C. Luschei, Karen A. Renner, Christy L. Sprague, Martin M. Williams Ii

Department of Agronomy and Horticulture: Faculty Publications

Weed seedbanks have been studied intensively at local scales, but to date, there have been no regional-scale studies of weed seedbank persistence. Empirical and modeling studies indicate that reducing weed seedbank persistence can play an important role in integrated weed management. Annual seedbank persistence of 13 summer annual weed species was studied from 2001 through 2003 at eight locations in the north central United States and one location in the northwestern United States. Effects of seed depth placement, tillage, and abiotic environmental factors on seedbank persistence were examined through regression and multivariate ordinations. All species examined showed a negative relationship …

Influence Of Soybean Row Width And Velvetleaf Emergence Time On Velvetleaf (Abutilon Theophrasti), Shawn M. Hock, Stevan Z. Knezevic, Alex R. Martin, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Row spacing and the relative time of velvetleaf emergence affects the time of soybean canopy closure relative to velvetleaf, influencing the growth and development of velvetleaf. Field studies were conducted in northeastern Nebraska in 2002 and 2003 to describe velvetleaf growth as influenced by soybean presence or absence (velvetleaf grown with soybean or in monoculture), soybean row spacing (19 and 76 cm), and relative time of velvetleaf emergence. Velvetleaf seed production, leaf area (LA), and total dry matter (TDM) were greater in 76-cm- than in 19-cm-wide soybean rows. LA, TDM, and seed production of velvetleaf were reduced with later emergence …

Species Diversity And Functional Composition Of Pastures That Vary In Landscape Position And Grazing Management, John A. Guretzky, Kenneth J. Moore, E. Charles Brummer, C. Lee Burras

Department of Agronomy and Horticulture: Faculty Publications

The productivity of grasslands depends in part on their diversity of species and functional composition. Our objective was to examine the effects of three landscape positions (summit, backslope, and toe-slope) and three stocking systems (continuous, rotational, and non-grazed) on species diversity and percentage of cover of grass, legume, and weed species functional types in southeastern Iowa pastures.Data were collected in 0.2-m² plots randomly distributed throughout each of four replicate pastures in spring and summer 2000 and 2001. Backslope landscape positions within pastures managed with either continuous or rotational stocking contained the greatest overall diversity of species. Across years, overall …

Leaf Radiative Properties And The Leaf Energy Budget, Timothy J. Arkebauer

Department of Agronomy and Horticulture: Faculty Publications

Leaf radiative properties are the physical properties of leaves that characterize radiant energy exchange with their surroundings. Radiant energy exchange is an important consideration in studies of plant function since, for example, absorption of photosynthetically active radiation (PAR) leads to the transformation of this energy into chemical energy via photosynthesis. Thus, plant productivity, and hence, agricultural production, ultimately depend on leaf radiative properties.

Leaf temperature is an additional, very important, parameter in intimate association with leaf radiant energy exchange. This association occurs since energy gained via radiation must be in balance with energy lost through various processes and energy loss …

Estimating Surface Wetness On Plants, R.D. Magarey, R.C. Seem, A. Weiss, T. Gillespie, L. Huber

Department of Agronomy and Horticulture: Faculty Publications

Plant surface (leaf, stem, petiole, etc) wetness or leaf wetness is an important agricultural weather variable for the prediction of plant diseases (Yarwood, 1978). The estimation of surface wetness has received considerable attention from a diverse group of scientists but unfortunately, no standard for measuring surface wetness has been widely accepted. Since surface wetness is not a true meteorological variable, as is temperature or precipitation, its measurement has not been routinely made as part of a general observation program by most national meteorological agencies. The main problem of not observing surface wetness on a routine basis has been the lack …

Self-Assembly Of Nanoparticles On Live Bacterium: An Avenue To Fabricate Electronic Devices, Ravi F. Saraf, Vikas Berry

Papers in Nanotechnology

Recently, hybrid structures of microorganisms with inorganic nanoscale moieties have received great interest owing to their potential in fabricating electronic systems. The electronic properties of metal nanoparticles, as a result of the singleelectron transport of current,[1] make them ideal materials for nanodevices. Concomitantly, the nanostructure of microorganisms such as bacteria,[2] viruses,[3, 4] and yeast[5] are attractive scaffolds for the templating of metal nanoparticles through the interactions of the former with surface charges and the affinity of certain metals for specific biological molecules.[2–7] However, the key challenges in building hybrid devices are 1) to pattern nanostructures without destroying the biological construct …

Crystallization And Preliminary X-Ray Analysis Of Na-Asp-1, A Multi-Domain Pathogenesis-Related-1 Protein From The Human Hookworm Parasite Necator Americanus, Oluwatoyin A. Asojo, Alex Loukas, Mehmet Inan, Rick Barent, Jicai Huang, Brad Plantz, Amber Swanson, Mark Gouthro, Michael M. Meagher, Peter J. Hotez

Department of Chemical and Biomolecular Engineering: Faculty Publications

Human hookworm infection is a major cause of anemia and malnutrition in the developing world. In an effort to control hookworm infection, the Human Hookworm Vaccine Initiative has identified candidate vaccine antigens from the infective larval stage (L3) of the parasite, including a family of pathogenesis-related-1 (PR-1) proteins known as the ancylostoma-secreted proteins (ASPs). The functions of the ASPs are unknown. In addition, it is unclear why some ASPs have one while others have multiple PR-1 domains. There are no known structures of a multi-domain ASP and in an effort to remedy this situation, recombinant Na-ASP-1 has been expressed, …

Evaluating Livestock System Environmental Performance With Whole-Farm Nutrient Balance, Richard K. Koelsch

Department of Agricultural and Biological Systems Engineering: Faculty Publications

As a part of the USEPA’s concentrated animal feeding operation (CAFO) final rule, all CAFOs are required to develop and implement a nutrient management plan (NMP). The USEPA’s emphasis on better management of nutrients appropriately targets a critical environmental issue associated with animal production. The concentration of animals in livestock feeding operations, often separate from feed grain production, requires importing of substantial quantities of feed nutrients. Due to the inefficiencies of nutrient utilization in livestock production, quantities of nitrogen (N) and phosphorus (P) in manure greater than can be utilized in local crop production often result. With the focus of …

Improvement Of Tractor Performance, K. U. Kim, Leonard L. Bashford, Brent T. Sampson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Improvement of agricultural tractor performance was analyzed using the data from 926 diesel tractors tested at the Nebraska Tractor Test Laboratory from 1959 through 2002. The performance analysis included the specific volumetric fuel consumption, power per unit weight, traction coefficient, maximum torque rise, and sound level. They were evaluated based on the PTO power level and chassis type of tractor. Some of the results are: (1) The average specific volumetric fuel consumptions for the maximum PTO and drawbar powers increased by 20.5% and 23.4% to 3.47 kW•h/L and 3.01 kW•h/L, respectively, from 1959 through 2002. (2) The average maximum PTO …

Takagi–Sugeno Fuzzy Modeling Of Skin Permeability, Deepak R. Keshwani, David D. Jones, Rhonda M. Brand

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The skin is a major exposure route for many potentially toxic chemicals. It is, therefore, important to be able to predict the permeability of compounds through skin under a variety of conditions. Available skin permeability databases are often limited in scope and not conducive to developing effective models. This sparseness and ambiguity of available data prompted the use of fuzzy set theory to model and predict skin permeability. Using a previously published database containing 140 compounds, a rule-based Takagi–Sugeno fuzzy model is shown to predict skin permeability of compounds using octanol-water partition coefficient, molecular weight, and temperature as inputs. Model …

Extraction Of Lipids From Grain Sorghum Ddg, L. Wang, Curtis L. Weller, K. T. Hwang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Soxhlet and recirculated solvent extraction methods were used to extract lipid materials from grain sorghum DDG. The lipid content in DDG with a moisture content of 6.7% (dry basis) was as high as 9.32% of the dried DDG as determined by Soxhlet extraction with n-hexane. There was a slight increase in the lipid yield from 9.21% to 9.68% when the moisture contents increased from 2.1% to 17.4% (d.b.). Thin-layer chromatography (TLC) analysis showed that the sorghum lipids were composed of triacylglycerols, fatty acids, fatty alcohols, fatty aldehydes, free sterols, wax esters, and steryl esters. A bench-scale recirculated extraction system was …

Finite Element Modeling And Experimental Validation Of Cooling Rates Of Large Ready-To-Eat Meat Products In Small Meat-Processing Facilities, A. Amézquita, L. Wang, Curtis L. Weller

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A two−dimensional axisymmetric transient heat conduction model was developed to simulate air chilling of large ready−to−eat meat products of ellipsoidal shape. A finite element scheme, using 1,600 linear triangular elements with 861 nodes, was implemented in Matlab 6.5 to solve the model. The model considered a variable initial temperature distribution and combined convective, radiative, and evaporative boundary conditions. Predicted values agreed well with experimental data collected in actual processing conditions. Validation of model performance resulted in maximum deviations of 2.54°C and 0.29% for temperature and weight loss histories, respectively. The maximum temperature deviation (2.54°C) occurred at the surface; however, for …

Policosanol Contents And Compositions In Wax-Like Materials Extracted From Selected Cereals Of Korean Origin, Keum Taek Hwang, Ji Eun Kim, Curtis L. Weller

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Policosanols. long-chained alcohols. have been reported to have beneficial physiological activities. Content and composition of policosanols in wax-like materials extracted from selected cereals of Korean origin were determined. Wax-like materials were extracted using hot hexane. Yields of wax-like materials from unpolished grain sorghum, polished grain sorghum. brown rice. purple rice, wheat, and maize were 223, 37, 33, 61, 10, and 10 mg/100 g of dry kernels, respectively. Policosanol contents, as determined using HPLC, in the wax-like materials from the cereals were 33, 29, 6.0, and 2% (w/w, db), respectively. Major alcohols in the policosanols from grain sorghum were octacosanol and …

Modeling Of Bubble Growth Dynamics And Nonisothermal Expansion In Starch-Based Foams During Extrusion, Lijun Wang, Girish M. Ganjyal, David D. Jones, Curtis L. Weller, Milford Hanna

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A mathematical model was developed to describe expansion phenomena in starch-based foams during extrusion. The model was divided into three parts to describe the microbubble growth dynamics, to couple bubble growth with extrudate expansion, and to describe the macrotransport phenomena in the extrudate, respectively. The differential equations involved in the model were solved by finite element schemes. For validating the model, the predicted radius, density, and residual moisture of final extrudate were compared with experimental data. Standard deviations between the predicted and experimental radius, density, and residual moisture of final extrudates were 16.7%, 11.2%, and 39.3%, respectively. The model was …

Root Zone Temperatures Of Viburnum Odoratissimum Grown In The Multipot Box System And Conventional Systems: Measurement And Analyses Of Temperature Profiles And Predicting Root Zone Temperatures, Suat Irmak, D. Z. Haman, Ayse Kilic, J. W. Jones, B. Tonkinson, D. Burch, T. H. Yeager, C. Larsen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This research study evaluates the effectiveness of a recently introduced irrigation- plant production system, multipot box system (MPBS), for moderating root zone temperature (RZT) compared with the conventional nursery containers. The study also deals with the development, calibration, and validation of a series of models that can be used to predict maximum (max) and minimum (min) RZTs using commonly available input variables. The Viburnum odoratissimum (Ker.-gawl.) was used as the test plant. Models were calibrated in the fall growing season and validated during the summer. The RZT was used as the dependent variable while the max and min air temperatures …

Evaluation Of Toxic Agent Effects On Lung Cells By Fiber Evanescent Wave Spectroscopy, Pierre Lucas, David Lee Coq, Christophe Juncker, Jayne Collier, Dianne E. Boesewetter, Catherine Boussard-Pledel, Bruno Bureau, Mark R. Riley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Biochemical changes in living cells are detected using a fiber probe system composed of a single chalcogenide fiber acting as both the sensor and transmission line for infrared optical signals. The signal is collected via evanescent wave absorption along the tapered sensing zone of the fiber. We spectroscopically monitored the effects of the surfactant Triton X-lOO, which serves as a toxic agent simulant on a transformed human lung carcinoma type II epithelial cell line (A549). We observe spectral changes between 2800-3000 cm-1 in four absorptions bands, which are assigned to hydrocarbon vibrations of methylene and methyl groups in membrane lipids. …

Evaluation Of Methods For Estimating Daily Reference Crop Evapotranspiration At A Site In The Humid Southeast United States, R. E. Yoder, Lameck O. Odhiambo, Wesley C. Wright

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Estimated daily reference crop evapotranspiration (ET_o) is normally used to determine the water requirement of crops using the crop factor method. Many ET_o estimation methods have been developed for different types of climatic data, and the accuracy of these methods varies with climatic conditions. In this study, pair−wise comparisons were made between daily ET_o estimated from eight different ET_o equations and ET_o measured by lysimeter to provide information helpful in selecting an appropriate ET_o equation for the Cumberland Plateau located in the humid Southeast United States. Based on the standard error of the …