Peer-Reviewed Journal Articles

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    For the Asian First and Then for the Westerner
    (1990) Stefanović, Zdravko
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    Daniel: A Book of Significant Reversals
    (1992) Stefanović, Zdravko
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    Spectrophotometric Determination of Bromate Ions Using Phenothiazines
    (1995) Farrell, E. Sebastian; Joa, J. F.; Pacey, Gilbert E.
    A highly sensitive spectrophotometric method for the determination of bromate ion is described. The method is based on the reduction of aqueous bromate ion by a phenothiazine in acidic conditions to produce a colored species. The method is suitable for bromate ion determination in the 1–700 μg/l range. For the most sensitive reagent, trifluoperazine, the limit of detection and limit of quantitation were calculated to be 0.67 and 2.25 μg/l, respectively.
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    Design and Evaluation of a New Thermospray Liquid/Liquid Extractor for the Extraction of Semivolatile and Nonvolatile Organic Compounds from Water
    (1996) Farrell, E. Sebastian; Pacey, Gilbert E.
    The recovery of several semivolatile organic compounds (SVOCs) using a new thermospray liquid/liquid extractor (TSLLE) was investigated. The base system includes a 300 mL multiport extraction vessel, jacketed in a 500 mL cooling flask, a dual-stage condenser for progressive cooling, several thermospray probes, and solvent/sample delivery systems. Aqueous mixtures of SVOCs were used to evaluate the TSLLE. For most compounds, recovery values of 80−100% were obtained during a single cycle in <1 h. The design, evaluation, and extraction capability of the TSLLE are discussed.
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    Behavior of Model Ionic Compounds under Thermospray Liquid/Liquid Extraction Conditions
    (1997) Farrell, E. Sebastian; Pacey, Gilbert E.
    Our previously reported procedure for the extraction of semivolatile and nonvolatile organic compounds from aqueous samples by thermospray liquid/liquid extraction was extended to the extraction of charged organic compounds from water. By thermally disrupting or extricating the solvation shell of hydrated ions, the thermospray process facilitates the extraction of these analytes from the aqueous matrix. The effects of probe temperature, probe flow rate, and sample pH on the extraction efficiency of model compounds such as phenylalanine, benzoate ion, p-toluenesulfonate ion, and naphthalenetrisulfonic acid trisodium salt were investigated. Under optimized conditions, the percent recoveries for these compounds were 95, 97, 91, and 13%, respectively.
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    Improving the Recovery of Ionic Solutes from Aqueous Media by Modified Thermospray Liquid-Liquid Extraction Conditions
    (2000) Farrell, E. Sebastian; Pacey, Gilbert E.
    Our previously reported procedure for the extraction of charged compounds from aqueous samples by thermospray liquid−liquid extraction (TSLLE) was essentially a one-step extraction involving large sample volumes. In this report, recirculative extraction, analysis of small sample volumes, the halide ion effect, and the effect of solvency or solvent modification on the extraction efficiency of benzoic acid (BA) by TSLLE were investigated. Compared to the one-step procedure that resulted in an extraction efficiency of only 28% for BA in n-hexane, recirculative TSLLE resulted in a BA recovery of 65% after five extraction cycles. When applied to sample volumes of 5−10 mL, TSLLE extracted BA with a precision of 2.8−6.1%. NaF, NaCl, and NaBr were also used to enhance analyte recovery. NaF gave the best recovery, 104%, for BA relative to the 88% obtained by batch processing. Some improvements in the extraction efficiency was observed when solvent modifiers such as methanol, ethanol, and 2-propanol were used.
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    Multi-Scale Breeding Bird and Land-cover Associations
    (Journal of the Tennessee Academy of Science, 2001) Butler, J. Russell
    The association patterns between breeding bird diversity and amount of different land cover types at five spatial scales were analyzed. Breeding bird surveys were conducted at 2,021 randomly selected roadside locations in a 500,000 ha area of north-central Tennessee. The land cover of the area was classified from satellite imagery. Both bird and land cover data were separated into relevant groups: birds into migration guilds, and land cover into natural and artificial types. The study area was subdivided into geographic blocks ranging from 36 to 62,000 ha. Study-area richness-distribution maps for each migration guild were created. The multiscale association patterns between bird species richness and proportion of land cover types were statistically analyzed using canonical and bivariate procedures. Residents displayed relatively even distributions. However, Neotropical migrant species displayed a large distribution gap in the southeast corner of the study area. Furthermore, residents did not display land cover associations, but Neotropical and short-distance migrants were significantly correlated with amount of land cover type over the breadth of the study scales. These findings suggest that migrants may be more sensitive to habitat changes than resident bird species. In addition, the multiscale results indicate the contextual and interrelated characteristics of the small- and large-scale patterns and processes. This suggests that local as well as regional scale areas need to be assessed in order to more effectively design management and conservation strategies.
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    The Spatial Impact of an Urban Area on Breeding Birds
    (Journal of the Tennessee Academy of Science, 2003) Butler, J. Russell
    Urbanization alters the landscape profoundly affecting plant and animal distributions and abundances. Urbanized areas negatively affect bird communities by favoring resident generalist or invasive species, in turn, reducing diversity and promoting local extinction. Even though urbanization affects biodiversity in many systems, the spatial extent to which a metropolitan area impacts biodiversity is not well characterized. The goal of the present study was to elucidate the areal extent to which an urban/suburban landscape affects avian diversity. I conducted a breeding-bird distribution study containing over 2,000 roadside survey locations in a 500,000 ha study area in north-central Tennessee, that contained areas of natural and urban (mainly the city of Nashville) land cover. Breeding bird species were divided into three guilds: those that breed and winter in the same area—residents; those that breed and winter in different but relatively close areas—short-distance migrants; and those that breed in North America and winter in Central and South America—Neotropical migrants. These data were spatially analyzed through spatial interpolation surface models: Kriging and linear surface models. Neotropical migrant richness exhibited stronger negative associations with urban land cover than either residents or short-distance migrants. The surface model for urban land cover formed urban density zones. Neotropical migrant total richness spatial patterns significantly corresponded to the urban spatial patterns. Neotropical migrant breeding bird richness was significantly less over a 150,000 ha area of urban/suburban-developed landscape, or an area 50 times larger than Nashville's downtown district. Assessment of the overall metropolitan spatial effect to diversity will provide a benchmark for areal urban/suburban impacts that can assist conservation and management strategies directed towards controlling environmental impacts of urban sprawl.
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    Dietary Supplementation of Endoxylanases and Phospholipase for Turkeys Fed Wheat-based Rations
    (2004) Santos, Anael A. Jr; Ferket, P. R.; Grimes, J. L.; Edens, F. W.
    The adverse effects of non-starch polysaccharides (NSP) on turkeys fed wheat-based diets may be alleviated by dietary supplementation of endoxylanase (to reduce the adverse effects of digesta viscosity) or phospholipase (to improve the digestibility of fat). BUTA toms were fed wheat-based diets containing one of 5 enzyme treatments: unsupplemented control, Natugrain Blend® (> 5,500 EXU/kg diet; NB), Lyxasan®-50 (> 2,250 EXU/kg diet; LX50), Lyxasan®-100 (> 5,500 EXU/kg diet; LX100), and Phospholipase (> 500 PLU/kg diet; PL) (BASF, Germany). Each treatment group was assigned to 8 pens containing 12 birds to evaluate growth performance (1-128 d), and 2 pens of 12 birds (excluding LX50) for the apparent metabolizable energy N-corrected (AMEn) and ileum viscosity determination (56-128 d). All enzyme treatments improved growth performance. In comparison to the control, dietary enzyme increased (P < 0.05) BW and decreased 1-128 d feed/gain (2.45 vs 2.37, P < 0.005). PL was most effective in reducing feed/gain during the starting phase and LX100 during the finishing phase, while NB had intermediate benefits throughout the experiment. PL increased AMEn from 9 to 12 wk, while NB and LX-100 resulted in the highest AMEn during the later finishing period. Viscosity was significantly higher for PL than the other treatments (13.5 vs 7.07 cP, P < 0.001). Growth performance and energy utilization of turkeys fed wheat-based diets can be significantly enhanced by phospholipase supplementation of starter feeds and endoxylanase supplementation of growing and finishing feeds. However, enzyme blends may provide a positive response regardless of turkey age.
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    Dietary Pentosanase Supplementation of Diets Containing Different Qualities of Wheat on Growth Performance and Metabolizable Energy of Turkey Poults
    (2004) Santos, Anael A. Jr; Ferket, P. R.; Grimes, J. L.; Edens, F. W.
    Wheat varies in apparent metabolizable energy N-corrected (AMEn) due to the presence of non-starch polysaccharides (NSP), which can be improved by dietary enzyme supplementation. Poults from 0-17 d-age were fed diets containing various wheat sources (WS) with or without Natugrain Blend® (NB) (BASF, Germany). Five replicate cages of 10 poults were assigned to each eight-soybean-meal/wheat treatment diets and a control soybean-meal/corn diet. The treatments were a factorial arrangement of 4 WS (A, B, C, D) and 2 enzyme levels (0 and 200 mg NB/kg). The WS differed by the degree of frost damage during seed development. Regardless of the source of wheat, NB increased 17 d BW (351 vs 381 g, P < 0.001), decreased 1-17 d FCR (1.55 vs 1.49, P < 0.05), increased AMEn (2,204 vs 2,455 kcal/kg, P < 0.001), and increased apparent nitrogen retention (ANR) (35.0 vs 41.4 %, P < 0.05). No effects of WS were seen on growth performance, but WS A and B had higher (P < 0.05) AMEn than sources C and D (2,396 and 2,460 vs 2,246 and 2,216 kcal/kg, respectively). Gut viscosity was higher (P < 0.05) in poults fed wheat-based diets than the control diet. Enzyme supplementation to the wheat-based diets decreased viscosity (5.57 vs 3.98 cP, P < 0.05) to a level similar to the corn-based control diet, and it resulted in equivalent growth performance. Viscosities were negatively correlated with AMEn. The results demonstrated a positive effect of enzyme supplementation on nutrient utilization and performance of turkeys.
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    Influence of Grain Particle Size and Insoluble Fiber Content on Salmonella Colonization and Shedding of Turkeys Fed Corn-Soybean Meal Diets
    (2006) Santos, F. B. O.; Santos, Anael A. Jr; Ferket, P. R.; Sheldon, B. W.
    This study aimed to determine the impact of feeding partially ground corn or insoluble fiber on intestinal development, Salmonella cecal colonization and fecal shedding of turkeys from 0-28d. Turkeys reared in cage-batteries were assigned to 1 of 3 diets: ground corn-SBM (GC, TRT 1), coarse ground corn-SBM (CC, TRT 2), and 4% wood shavings + ground corn-SBM (SC, TRT 3). A 3-strain cocktail of nalidixic acid-resistant Salmonella enterica serotypes Hadar, Javaina, and Typhimurium was orally-gavaged into each poult at placement. Cecal and fecal Salmonella populations, growth performance and intestinal weights and lengths were measured. The diets had no impact on Salmonella cecal or fecal populations. At 28d, Salmonella cecal populations decreased approximately 3-logs (range: 2.4-3.3 log reduction) across all treatments in comparison to 7d (P< 0.0001). At 28d body weight, body gain and feed conversion ratio were not impacted by the diets. However, at 14d poults consuming the SC diet had lower feed consumption than those fed the GC and CC diets (231 vs. 243 and 252 g, P=0.001, respectively). The CC diet resulted in heavier relative gizzard weights at 28d in comparison to the GC and SC diets (30 vs. 28 and 22 g/kg, respectively, P< 0.0001). Conversely, the SC treatment reduced the mass of the small intestine relative to body weight, especially the jejunum. Dietary inclusion of coarsely ground corn and wood shavings had no adverse effect on growth performance yet improved gizzard and intestinal development, which could have positive effects on intestinal health.
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    Dynamics of Poly(styrenesulfonate) Sodium Salt in Aqueous Solution
    (2006) Cong, Rongjuan; Temyanko, Elena; Russo, Paul S.; Edwin, Nadia J.; Uppu, Rao M.
    The diffusion of poly(styrenesulfonate) sodium salt (NaPSS) was investigated using dialysis dynamic light scattering (DLS) and dialysis fluorescence photobleaching recovery (FPR). Never-dried or “virgin” NaPSS was synthesized directly from 4-styrenesulfonic sodium salt to achieve 100% sulfonation. Upon reducing the ionic strength directly in the DLS cell by dialysis, a clean sample developed clearly distinct fast and slow modes that were first identified as an extraordinary phase in low-salt solutions of poly-l-lysine by Lin, Lee, and Schurr [Biopolymers1978, 17, 1041]. This result complements published polyelectrolyte investigations in a high-dielectric constant organic solvent, and also studies where the degree of ionization was tuned, which confirms that hydrophobic patches along the polymer chain are not required for the extraordinary behavior. The fast mode dominated even at low ionic strength, with scattering amplitude exceeding 70% of the total. For the virgin NaPSS sample in the dialysis cell, there is no convincing evidence of a slow mode at high salt (≥200 mM NaCl). The appearance of distinct slow and fast modes proved reversible upon removing and adding salt by dialysis, without any other perturbation save restoration of the concentration by dialysis centrifugation. This suggests that the behavior represents a thermodynamically equilibrated state. Dialysis FPR measurements of aqueous solutions of a commercial NaPSS that was labeled with fluoresceinamine (LNaPSS) showed no obvious long-range ordering. A reversible decrease in the optical tracer self-diffusion coefficient of LNaPSS as salt is dialyzed out of the solution is instead attributed to chain expansion. Comparison of FPR and DLS on a mixed LNaPSS/NaPSS sample suggests that the residence time of a chain in temporal aggregates [Schmitz et al. Biopolymers1984, 23, 1637] that are thought to be responsible for the DLS slow mode is shorter than the FPR time scale.
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    Determination of Ileum Microbial Diversity of Broilers Fed Triticale- or Corn-based Diets and Colonized by Salmonella
    (2007) Santos, F. B. O.; Sheldon, B. W.; Santos, Anael A. Jr; Ferket, P. R.; Lee, M. D.; Smith, D.
    Diversity of the bacterial communities in the ileum of broilers was characterized using denaturing gradient gel electrophoresis. Denaturing gradient gel electrophoresis separation of polymerase chain reaction amplicons of the V2–V3 variable regions of the 16S rDNA is a common method to profile community diversity and has been used to assess the effects of diet and antibiotics on the ileal bacterial community of chickens. Broilers raised either on litter floor or in cage batteries were fed either a finely ground corn- (control), a finely ground triticale-, or a whole triticale-based diet from 0 to 42 d. Microbial DNA was extracted from the ileum content of 42-d-old broilers, and the 16S rDNA gene was amplified by polymerase chain reaction and the amplicons separated by denaturing gradient gel electrophoresis. Diversity indexes including richness, evenness, diversity, and pairwise similarity coefficients were calculated. Diversity indexes were related to the dietary treatments, housing designs, and to changes in Salmonella colonization of broiler ceca as characterized by the most probable number method. Higher microbial diversity indexes were observed among birds fed whole triticale-based diets and reared on litter floors. In contrast, finely ground grain treatments had lower diversity and higher Salmonella prevalence than the whole triticale treatment. The data indicated that combination of high dietary fiber content and increased coarseness of the diet by feeding whole triticale stimulated microbial community diversity and discouraged Salmonella colonization, perhaps through a competitive exclusion-type mechanism.
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    Temperature-associated Dynamics of Songbird Winter Distribution and Abundances
    (2007) Butler, J. Russell; MacMynowski, Dena P.; Laurent, Chad; Root, Terry L.
    Using Christmas Bird Count data, we analyze the annual spatio-temporal abundances of six passerine species in the upper Great Plains, US (1960-1990). This study provides new insight into how global warming could cause separation of species within present-day communities. We find that winter relative abundances of similarly-sized songbirds are differentially affected by ambient winter temperature. As such, average annual winter temperature fluctuations (i.e., severity of winter) are significantly (P < 0.05) correlated with the relative abundances of three species while the other three are not. Our conditional probability-of-occurrence analysis indicates that the abundances of the three temperature-associated species declined markedly below -4°C while the abundances of the other three species fluctuated little from 8°C to -16°C. We conclude that even in colder climates i) the winter distributions of some, but not all, songbirds are directly or indirectly limited by temperature; and ii) these birds have dynamic abundances that can quickly respond to temperature changes.