Publications by authors named "Scott Knight"

22 Publications

  • Page 1 of 1

Impact of Intervention on College Students' Vending Selections.

J Am Coll Health 2021 Apr 2:1-7. Epub 2021 Apr 2.

Department of Nutrition and Hospitality Management, The University of Mississippi, University, Oxford, Mississippi, USA.

Objectives: To place in vending machines and determine if different sales strategies affect selection.

Participants: University students living in resident halls.

Methods: Vending machines included 50% and 50% non compliant snacks. Three sales strategies targeted student selection of : Reduced price, signage, and nutrition education activities. Three-way ANOVA was used for analysis.

Results: There was a statistically significant three-way interaction on snack selection between sales strategy, study period, and snack type, (4, 77) = 3.33, = .01. There were no statistically significant simple two-way interaction between study period and sales strategy for either , (1, 77) = 1.62,  = 0.18, or NC snack types, (1, 77) = 2.02,  = 0.07.

Conclusions: Sales strategies did not affect selections. Advocates for healthier snacks in vending machines can align with
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http://dx.doi.org/10.1080/07448481.2021.1909048DOI Listing
April 2021

Physical activity in the Families in Transformation (FIT) weight management program for children.

Health Promot Perspect 2018 7;8(3):237-242. Epub 2018 Jul 7.

Director of University of Mississippi Field Station, University of Mississippi, University, MS, USA.

The purpose was to determine if an 8-week nutrition education and exercise program for families could influence health and fitness parameters, and retention of nutrition knowledge. Eighteen children (mean age: 10.52 ± 1.26 year; 50% boys, 50% girls; 56% white, 25% black, 19% multiracial) participated in the Families in Transformation (FIT) program. Preand post-study anthropocentric, blood pressure, fitness, and nutrition knowledge data was collected. Diastolic blood pressure decreased for the total group (66.63 ± 8.81 to 63.75 ± 11.81mm Hg). Significant (P < 0.05) increases were seen for the group for push-ups (14.31 ± 7.62 to 19.63 ± 6.62) and chair squats (30.50 ± 10.21 to 34.44 ± 7.39). The reinforcing physical activity group performed significantly better on nutrition knowledge quizzes. Although, body mass index (BMI) z-scores did not change, there was a decrease in diastolic blood pressure, increase in fitness parameters, and increased retention of nutrition knowledge.
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http://dx.doi.org/10.15171/hpp.2018.32DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6064755PMC
July 2018

Lake Nutrient Responses to Integrated Conservation Practices in an Agricultural Watershed.

J Environ Qual 2017 Mar;46(2):330-338

Watershed-scale management efforts to reduce nutrient loads and improve the conservation of lakes in agricultural watersheds require effective integration of a variety of agricultural conservation best management practices (BMPs). This paper documents watershed-scale assessments of the influence of multiple integrated BMPs on oxbow lake nutrient concentrations in a 625-ha watershed of intensive row-crop agricultural activity during a 14-yr monitoring period (1996-2009). A suite of BMPs within fields and at field edges throughout the watershed and enrollment of 87 ha into the Conservation Reserve Program (CRP) were implemented from 1995 to 2006. Total phosphorus (TP), soluble reactive phosphorus (SRP), ammonium, and nitrate were measured approximately biweekly from 1996 to 2009, and total nitrogen (TN) was measured from 2001 to 2009. Decreases in several lake nutrient concentrations occurred after BMP implementation. Reductions in TP lake concentrations were associated with vegetative buffers and rainfall. No consistent patterns of changes in TN or SRP lake concentrations were observed. Reductions in ammonium lake concentrations were associated with conservation tillage and CRP. Reductions in nitrate lake concentrations were associated with vegetative buffers. Watershed simulations conducted with the AnnAGNPS (Annualized Agricultural Non-Point Source) model with and without BMPs also show a clear reduction in TN and TP loads to the lake after the implementation of BMPs. These results provide direct evidence of how watershed-wide BMPs assist in reducing nutrient loading in aquatic ecosystems and promote a more viable and sustainable lake ecosystem.
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http://dx.doi.org/10.2134/jeq2016.08.0324DOI Listing
March 2017

Locus-specific epigenetic remodeling controls addiction- and depression-related behaviors.

Nat Neurosci 2014 Dec 27;17(12):1720-7. Epub 2014 Oct 27.

Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.

Chronic exposure to drugs of abuse or stress regulates transcription factors, chromatin-modifying enzymes and histone post-translational modifications in discrete brain regions. Given the promiscuity of the enzymes involved, it has not yet been possible to obtain direct causal evidence to implicate the regulation of transcription and consequent behavioral plasticity by chromatin remodeling that occurs at a single gene. We investigated the mechanism linking chromatin dynamics to neurobiological phenomena by applying engineered transcription factors to selectively modify chromatin at a specific mouse gene in vivo. We found that histone methylation or acetylation at the Fosb locus in nucleus accumbens, a brain reward region, was sufficient to control drug- and stress-evoked transcriptional and behavioral responses via interactions with the endogenous transcriptional machinery. This approach allowed us to relate the epigenetic landscape at a given gene directly to regulation of its expression and to its subsequent effects on reward behavior.
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http://dx.doi.org/10.1038/nn.3871DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4241193PMC
December 2014

Engineered zinc-finger transcription factors activate OCT4 (POU5F1), SOX2, KLF4, c-MYC (MYC) and miR302/367.

Nucleic Acids Res 2014 Jun 3;42(10):6158-67. Epub 2014 May 3.

Sigma-Aldrich Corporation, Saint Louis, MO 63103, USA

Artificial transcription factors are powerful tools for regulating gene expression. Here we report results with engineered zinc-finger transcription factors (ZF-TFs) targeting four protein-coding genes, OCT4, SOX2, KLF4 and c-MYC, and one noncoding ribonucleic acid (RNA) gene, the microRNA (miRNA) miR302/367 cluster. We designed over 300 ZF-TFs whose targets lie within 1 kb of the transcriptional start sites (TSSs), screened them for increased messenger RNA or miRNA levels in transfected cells, and identified potent ZF-TF activators for each gene. Furthermore, we demonstrate that selected ZF-TFs function with alternative activation domains and in multiple cell lines. For OCT4, we expanded the target range to -2.5 kb and +500 bp relative to the TSS and identified additional active ZF-TFs, including three highly active ZF-TFs targeting distal enhancer, proximal enhancer and downstream from the proximal promoter. Chromatin immunoprecipitation (FLAG-ChIP) results indicate that several inactive ZF-TFs targeting within the same regulatory region bind as well as the most active ZF-TFs, suggesting that efficient binding within one of these regulatory regions may be necessary but not sufficient for activation. These results further our understanding of ZF-TF design principles and corroborate the use of ZF-TFs targeting enhancers and downstream from the TSS for transcriptional activation.
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http://dx.doi.org/10.1093/nar/gku243DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4041418PMC
June 2014

Role in tumor growth of a glycogen debranching enzyme lost in glycogen storage disease.

J Natl Cancer Inst 2014 Apr 3;106(5). Epub 2014 Apr 3.

Affiliations of authors: Department of Surgery (SGui, CP, YR, CRL, JED, GD, CO, DT) and Department of Pharmacology (SGui, CP, YR, CRL, JED, GD, CO, DT), University of Colorado, Denver, CO; Sigma-Aldrich Research Biotech, Saint Louis, MO (AS, SK, HH); Department of Pathology, Cleveland Clinic, Cleveland, OH (SGup, DH); Department of Nutritional Sciences and Toxicology, University of California at Berkeley, Berkeley, CA (MH); Department of Medicine, University of California at San Francisco, San Francisco, CA (MH); Center for Regulatory and Environmental Analytical Metabolomics, Department of Chemistry, University of Louisville, Louisville, KY (PL); Graduate Center of Toxicology, Biopharm Complex, University of Kentucky, Lexington, KY (ANL, TW-MF); University of Colorado Comprehensive Cancer Center, Denver, CO (DT). Present affiliations: Department of Biomedical Informatics, Windber Research Institute, Windber, PA (YR); Mathematics and Computer Science Department, Eastern Connecticut State University, Willimantic, CT (GD).

Background: Bladder cancer is the most common malignancy of the urinary system, yet our molecular understanding of this disease is incomplete, hampering therapeutic advances.

Methods: Here we used a genome-wide functional short-hairpin RNA (shRNA) screen to identify suppressors of in vivo bladder tumor xenograft growth (n = 50) using bladder cancer UMUC3 cells. Next-generation sequencing was used to identify the most frequently occurring shRNAs in tumors. Genes so identified were studied in 561 patients with bladder cancer for their association with stratification of clinical outcome by Kaplan-Meier analysis. The best prognostic marker was studied to determine its mechanism in tumor suppression using anchorage-dependent and -independent growth, xenograft (n = 20), and metabolomic assays. Statistical significance was determined using two-sided Student t test and repeated-measures statistical analysis.

Results: We identified the glycogen debranching enzyme AGL as a prognostic indicator of patient survival (P = .04) and as a novel regulator of bladder cancer anchorage-dependent (P < .001), anchorage-independent (mean ± standard deviation, 180 ± 23.1 colonies vs 20±9.5 in control, P < .001), and xenograft growth (P < .001). Rescue experiments using catalytically dead AGL variants revealed that this effect is independent of AGL enzymatic functions. We demonstrated that reduced AGL enhances tumor growth by increasing glycine synthesis through increased expression of serine hydroxymethyltransferase 2.

Conclusions: Using an in vivo RNA interference screen, we discovered that AGL, a glycogen debranching enzyme, has a biologically and statistically significant role in suppressing human cancer growth.
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http://dx.doi.org/10.1093/jnci/dju062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4580555PMC
April 2014

Mitigating agrichemicals from an artificial runoff event using a managed riverine wetland.

Sci Total Environ 2012 Jun 4;427-428:373-81. Epub 2012 May 4.

USDA-ARS National Sedimentation Laboratory, Oxford, MS 38655, USA.

We examined the mitigation efficiency of a managed riverine wetland amended with a mixture of suspended sediment, two nutrients (nitrogen and phosphorus), and three pesticides (atrazine, metolachlor, and permethrin) during a simulated agricultural runoff event. Hydrologic management of the 500 m-long, 25 m-wide riverine wetland was done by adding weirs at both ends. The agrichemical mixture was amended to the wetland at the upstream weir simulating a four-hour, ~1cm rainfall event from a 16ha agricultural field. Water samples (1L) were collected every 30 min within the first 4h, then every 4h until 48 h, and again on days 5, 7, 14, 21, and 28 post-amendment at distances of 0m, 10 m, 40 m, 300 m and 500 m from the amendment point within the wetland for suspended solids, nutrient, and pesticide analyses. Peak sediment, nutrient, and pesticide concentrations occurred within 3 h of amendment at 0m, 10 m, 40 m, and 300 m downstream and showed rapid attenuation of agrichemicals from the water column with 79-98%, 42-98%, and 63-98% decrease in concentrations of sediments, nutrients, and pesticides, respectively, within 48 h. By day 28, all amendments were near or below pre-amendment concentrations. Water samples at 500 m showed no changes in sediment or nutrient concentrations; pesticide concentrations peaked within 48 h but at ≤11% of upstream peak concentrations and had dissipated by day 28. Managed riverine wetlands≥1 ha and with hydraulic residence times of days to weeks can efficiently trap agricultural runoff during moderate (1cm) late-spring and early-summer rainfall events, mitigating impacts to receiving rivers.
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http://dx.doi.org/10.1016/j.scitotenv.2012.04.025DOI Listing
June 2012

Responses of Hyalella azteca and phytoplankton to a simulated agricultural runoff event in a managed backwater wetland.

Chemosphere 2012 May 13;87(7):684-91. Epub 2012 Jan 13.

USDA - ARS National Sedimentation Laboratory, Oxford, MS 38655, USA.

We assessed the aqueous toxicity mitigation capacity of a hydrologically managed floodplain wetland following a synthetic runoff event amended with a mixture of sediments, nutrients (nitrogen and phosphorus), and pesticides (atrazine, S-metolachlor, and permethrin) using 48-h Hyalella azteca survival and phytoplankton pigment, chlorophyll a. The runoff event simulated a 1h, 1.27 cm rainfall event from a 16 ha agricultural field. Water (1L) was collected every 30 min within the first 4h, every 4h until 48 h, and on days 5, 7, 14, 21, and 28 post-amendment at distances of 0, 10, 40, 300 and 500 m from the amendment point for chlorophyll a, suspended sediment, nutrient, and pesticide analyses. H. azteca 48-h laboratory survival was assessed in water collected at each site at 0, 4, 24, 48 h, 5 d and 7 d. Greatest sediment, nutrient, and pesticide concentrations occurred within 3h of amendment at 0m, 10 m, 40 m, and 300 m downstream. Sediments and nutrients showed little variation at 500 m whereas pesticides peaked within 48 h but at <15% of upstream peak concentrations. After 28 d, all mixture components were near or below pre-amendment concentrations. H. azteca survival significantly decreased within 48 h of amendment up to 300 m in association with permethrin concentrations. Chlorophyll a decreased within the first 24h of amendment up to 40m primarily in conjunction with herbicide concentrations. Variations in chlorophyll a at 300 and 500 m were associated with nutrients. Managed floodplain wetlands can rapidly and effectively trap and process agricultural runoff during moderate rainfall events, mitigating impacts to aquatic invertebrates and algae in receiving aquatic systems.
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http://dx.doi.org/10.1016/j.chemosphere.2011.12.058DOI Listing
May 2012

RNA interference in marine and freshwater sponges: actin knockdown in Tethya wilhelma and Ephydatia muelleri by ingested dsRNA expressing bacteria.

BMC Biotechnol 2011 Jun 16;11:67. Epub 2011 Jun 16.

Department of Biology, University of Richmond, Richmond, VA, USA.

Background: The marine sponge Tethya wilhelma and the freshwater sponge Ephydatia muelleri are emerging model organisms to study evolution, gene regulation, development, and physiology in non-bilaterian animal systems. Thus far, functional methods (i.e., loss or gain of function) for these organisms have not been available.

Results: We show that soaking developing freshwater sponges in double-stranded RNA and/or feeding marine and freshwater sponges bacteria expressing double-stranded RNA can lead to RNA interference and reduction of targeted transcript levels. These methods, first utilized in C. elegans, have been adapted for the development and feeding style of easily cultured marine and freshwater poriferans. We demonstrate phenotypic changes result from 'knocking down' expression of the actin gene.

Conclusion: This technique provides an easy, efficient loss-of-function manipulation for developmental and gene regulatory studies in these important non-bilaterian animals.
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http://dx.doi.org/10.1186/1472-6750-11-67DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3146823PMC
June 2011

Toxicity evaluation of a conservation effects assessment program watershed, Beasley Lake, in the Mississippi Delta, USA.

Bull Environ Contam Toxicol 2010 Apr 14;84(4):422-6. Epub 2010 Mar 14.

USDA-ARS National Sedimentation Laboratory, PO Box 1157, Oxford, MS 38655, USA.

Beasley Lake was assessed monthly in 2005 for biological impairment from 17 historic and current-use pesticides in water and leaf litter using Hyalella azteca (Saussure). Sixteen pesticides were detected in both water and leaf litter with peak detections in spring and summer. Detections ranged from 1-125 ng L(-1) in water and 1-539 ng g(-1) OC in leaf litter. Ten-day H. azteca survival and growth (mg dw) bioassay results indicated no adverse effects on survival or growth in H. azteca exposed to water or leaf litter. Rather, enhanced growth occurred in both lake water and leaf litter exposures for 8 and 6 months, respectively.
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http://dx.doi.org/10.1007/s00128-010-9951-xDOI Listing
April 2010

Effects of an atrazine, metolachlor and fipronil mixture on Hyalella azteca (Saussure) in a modified backwater wetland.

Bull Environ Contam Toxicol 2009 Dec;83(6):836-40

USDA-ARS National Sedimentation Laboratory, P.O. Box 1157, Oxford, MS 38655, USA.

We examined the toxicity mitigation efficiency of a hydrologically modified backwater wetland amended with a pesticide mixture of atrazine, metolachlor, and fipronil, using 96 h survival bioassays with Hyalella azteca. Significant H. azteca 96 h mortality occurred within the first 2 h of amendment at the upstream amendment site but not at any time at the downstream site. H. azteca survival varied spatially and temporally in conjunction with measured pesticide mixture concentrations. Hyalella azteca 96 h survival pesticide mixture effects concentrations ranges were 10.214–11.997, 5.822–6.658, 0.650–0.817, and 0.030–0.048 μg L−1 for atrazine, metolachlor, fipronil, and fipronil-sulfone, respectively.
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http://dx.doi.org/10.1007/s00128-009-9850-1DOI Listing
December 2009

Hyalella azteca (Saussure) responses to Coldwater River backwater sediments in Mississippi, USA.

Bull Environ Contam Toxicol 2009 Oct 7;83(4):493-6. Epub 2009 Jul 7.

USDA-ARS National Sedimentation Laboratory, P.O. Box 1157, Oxford, MS 38655, USA.

Sediment from three Coldwater River, Mississippi backwaters was examined using 28 day Hyalella azteca bioassays and chemical analyses for 33 pesticides, seven metals and seven PCB mixtures. Hydrologic connectivity between the main river channel and backwater varied widely among the three sites. Mortality occurred in the most highly connected backwater while growth impairment occurred in the other two. Precopulatory guarding behavior was not as sensitive as growth. Fourteen contaminants (seven metals, seven pesticides) were detected in sediments. Survival was associated with the organochlorine insecticide heptachlor.
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http://dx.doi.org/10.1007/s00128-009-9804-7DOI Listing
October 2009

Agricultural pesticides in Mississippi Delta oxbow lake sediments during autumn and their effects on Hyalella azteca.

Arch Environ Contam Toxicol 2009 Oct 28;57(3):495-503. Epub 2009 Apr 28.

USDA-ARS National Sedimentation Laboratory, PO Box 1157, Oxford, MS 38655, USA.

Agricultural pesticide contamination of sediments from five Mississippi Delta oxbow lakes and their effects and bioavailablity to Hyalella azteca were assessed during a low-application season-autumn. Three reference oxbow lakes were located in the White River National Wildlife Refuge (WRNWR), Arkansas and two impaired lakes, according to the US Environmental Agency Sect. 303 (d) Clean Water Act, were located in Mississippi. Surface sediment (top 5 cm) was collected at three sites within each lake and analyzed for 17 current and historic-use pesticides and metabolites. Chronic 28-day H. azteca sediment bioassays and pesticide body residue analyses were completed to determine the degree of biological responses and bioavailability. The greatest number of detectable pesticides in WRNWR and 303 (d) sediment samples was 9 and 12, respectively, with historic-use pesticide metabolite, p,p'-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] ubiquitous. No significant (p > 0.05) differences in animal survival were observed among sites. Animal growth was significantly (p < 0.05) less at only one site in a 303 (d)-listed lake (Macon Lake). Only six pesticides were observed in H. azteca with current-use pesticides detected at three sites; historic-use pesticides and metabolites detected at 11 sites. Animal body residues of a historic-use pesticide (dieldrin) and metabolite (p,p'-DDE) were associated with observed growth responses. Results show limited current-use pesticide contamination of sediments and H. azteca body tissues during autumn and that historic-use pesticides and metabolites are the primary contributors to observed biological responses.
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http://dx.doi.org/10.1007/s00244-009-9327-6DOI Listing
October 2009

Reduction of turbulent boundary layer induced interior noise through active impedance control.

J Acoust Soc Am 2008 Mar;123(3):1427-38

BBN Technologies, 10 Moulton Street, Cambridge, Massachusetts 02138, USA.

The use of a single actuator tuned to an optimum impedance to control the sound power radiated from a turbulent boundary layer (TBL) excited aircraft panel into the aircraft interior is examined. An approach to calculating the optimum impedance is defined and the limitations on the reduction in radiated power by a single actuator tuned to that impedance are examined. It is shown that there are too many degrees of freedom in the TBL and in the radiation modes of the panel to allow a single actuator to control the radiated power. However, if the panel modes are lightly damped and well separated in frequency, significant reductions are possible. The implementation of a controller that presents a desired impedance to a structure is demonstrated in a laboratory experiment, in which the structure is a mass. The performance of such a controller on an aircraft panel is shown to be effective, if the actuator impedance is similar to but not the same as the desired impedance, provided the panel resonances are well separated in frequency and lightly damped.
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http://dx.doi.org/10.1121/1.2835608DOI Listing
March 2008

Glia maturation factor overexpression in neuroblastoma cells activates glycogen synthase kinase-3beta and caspase-3.

Brain Res 2008 Jan 13;1190:206-14. Epub 2007 Nov 13.

Veterans Affair Medical Center, Iowa City, IA, USA.

In the present study we report that a replication-defective adenovirus construct of GMF cDNA (GMF-V) induced overexpression of GMF protein in neuroblastoma (N18) cells caused cytotoxicity and loss of cell viability. A significant increase in activation of GSK-3beta occurred after infection with GMF-V when compared with mock and lacZ controls. Overexpression of GMF also increased caspase-3 activity, an early marker of apoptosis. Depletion of GMF gene by introducing GMF-specific siRNA (GsiRNA) completely blocked both activation of GSK-3beta and caspase-3 activation whereas a control scrambled siRNA (CsiRNA) had no effect. A cell-permeable peptide inhibitor of GSK-3beta, and lithium completely prevented GMF-dependent activation of caspase-3. These results demonstrate that GSK-3 mediates activation of the death domain caspase by GMF overexpression. We also show that the phosphorylation of GSK-3-dependent site of Tau was a consequence of GMF-overexpression in N18 cells. Taken together our results imply that GMF is involved in the signaling leading to the activation of GSK-3beta and caspase-3 in N18 cells and strongly suggest its involvement in neurodegeneration since GSK-3beta is known to hyperphosphorylate tau which is associated with the neurotoxicity of neurofibrillary tangles in Alzheimer's disease.
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http://dx.doi.org/10.1016/j.brainres.2007.11.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2343001PMC
January 2008

Can warmwater streams be rehabilitated using watershed-scale standard erosion control measures alone?

Environ Manage 2007 Jul 26;40(1):62-79. Epub 2007 Apr 26.

Water Quality and Ecology Research Unit, National Sedimentation Laboratory, U.S. Department of Agriculture Agricultural Research Service, P.O. Box 1157, Oxford, MS 38655-1157, USA.

Degradation of warmwater streams in agricultural landscapes is a pervasive problem, and reports of restoration effectiveness based on monitoring data are rare. Described is the outcome of rehabilitation of two deeply incised, unstable sand-and-gravel-bed streams. Channel networks of both watersheds were treated using standard erosion control measures, and aquatic habitats within 1-km-long reaches of each stream were further treated by addition of instream structures and planting woody vegetation on banks ("habitat rehabilitation"). Fish and their habitats were sampled semiannually during 1-2 years before rehabilitation, 3-4 years after rehabilitation, and 10-11 years after rehabilitation. Reaches with only erosion control measures located upstream from the habitat measure reaches and in similar streams in adjacent watersheds were sampled concurrently. Sediment concentrations declined steeply throughout both watersheds, with means > or = 40% lower during the post-rehabilitation period than before. Physical effects of habitat rehabilitation were persistent through time, with pool habitat availability much higher in rehabilitated reaches than elsewhere. Fish community structure responded with major shifts in relative species abundance: as pool habitats increased after rehabilitation, small-bodied generalists and opportunists declined as certain piscivores and larger-bodied species such as centrarchids and catostomids increased. Reaches without habitat rehabilitation were significantly shallower, and fish populations there were similar to the rehabilitated reaches prior to treatment. These findings are applicable to incised, warmwater streams draining agricultural watersheds similar to those we studied. Rehabilitation of warmwater stream ecosystems is possible with current knowledge, but a major shift in stream corridor management strategies will be needed to reverse ongoing degradation trends. Apparently, conventional channel erosion controls without instream habitat measures are ineffective tools for ecosystem restoration in incised, warmwater streams of the Southeastern U.S., even if applied at the watershed scale and accompanied by significant reductions in suspended sediment concentration.
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http://dx.doi.org/10.1007/s00267-006-0191-0DOI Listing
July 2007

A novel role of glia maturation factor: induction of granulocyte-macrophage colony-stimulating factor and pro-inflammatory cytokines.

J Neurochem 2007 Apr 22;101(2):364-76. Epub 2007 Jan 22.

Veterans Affair Medical Center, Iowa City, Iowa, USA.

The glia maturation factor (GMF), which was discovered in our laboratory, is a highly conserved protein predominantly localized in astrocytes. GMF is an intracellular regulator of stress-related signal transduction. We now report that the overexpression of GMF in astrocytes leads to the destruction of primary oligodendrocytes by interactions between highly purified cultures of astrocytes, microglia, and oligodendrocytes. We infected astrocytes with a replication-defective adenovirus carrying the GMF cDNA. The overexpression of GMF caused the activation of p38 MAP kinase and transcription factor NF-kappaB, as well as the induction of granulocyte-macrophage colony-stimulating factor (GM-CSF) mRNA and protein in astrocytes. Small interfering RNA-mediated GMF knockdown completely blocked the GMF-dependent activation of p38 mitogen-activated protein kinase (MAPK), NF-kappaB, and enhanced expression of GM-CSF by astrocytes. Inhibition of p38 MAPK or NF-kappaB by specific inhibitors prevented GM-CSF production. The cell-free conditioned medium from overexpressing GMF astrocytes contained 320 +/- 33 pg/mL of GM-CSF, which was responsible for enhanced production and secretion of TNF-alpha, IL-1beta, IL-6, and IP-10 by microglia. Presence of these inflammatory cytokines in the conditioned medium from microglia efficiently destroyed oligodendrocytes in culture. These results suggest that GMF-induced production of GM-CSF in astrocytes is depending on p38 MAPK and NF-kappaB activation. The GM-CSF-dependent expression and secretion of inflammatory cytokine/chemokine, TNF-alpha, IL-1beta, IL-6, and IP-10, is cytotoxic to oligodendrocytes, the myelin-forming cells in the central nervous system, and as well as neurons. Our results suggest a novel pathway of GMF-initiated cytotoxicity of brain cells, and implicate its involvement in inflammatory diseases such as multiple sclerosis.
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http://dx.doi.org/10.1111/j.1471-4159.2006.04385.xDOI Listing
April 2007

Influence of watershed system management on herbicide concentrations in Mississippi Delta oxbow lakes.

Sci Total Environ 2006 Nov 26;370(2-3):552-60. Epub 2006 Sep 26.

USDA Agricultural Research Service, Southern Weed Science Research Unit, Stoneville, MS 38776, USA.

The Mississippi Delta Management Systems Evaluation Area (MD-MSEA) project was established in 1994 in three small watersheds (202 to 1,497 ha) that drain into oxbow lakes (Beasley, Deep Hollow, and Thighman). The primary research objective was to assess the implications of management practices on water quality. Monthly monitoring of herbicide concentrations in lake water was conducted from 2000 to 2003. Water samples were analyzed for atrazine, cyanazine, fluometuron, metolachlor, and atrazine metabolites. Herbicide concentrations observed in the lake water reflected cropping systems of the watershed, e.g., atrazine and metolachlor concentrations were associated with the level of corn and sorghum production, whereas cyanazine and fluometuron was associated with the level of glyphosate-sensitive cotton production. The dynamics of herbicide appearance and dissipation in lake samples were strongly influenced by herbicide use, lake hydrology, rainfall pattern, and land management practices. The highest maximum concentrations of atrazine (7.1 to 23.4 microg L(-1)) and metolachlor (0.7 to 14.9 microg L(-1)) were observed in Thighman Lake where significant quantities of corn were grown. Introduction of s-metolachlor and use of glyphosate-resistant cotton coincided with reduced concentration of metolachlor in lake water. Cyanazine was observed in two lakes with the highest levels (1.6 to 5.5 microg L(-1)) in 2000 and lower concentrations in 2001 and 2002 (<0.4 microg L(-1)). Reduced concentrations of fluometuron in Beasley Lake were associated with greater use of glyphosate-resistant cotton and correspondingly less need for soil-applied fluometuron herbicide. In contrast, increased levels of fluometuron were observed in lake water after Deep Hollow was converted from conservation tillage to conventional tillage, presumably due to greater runoff associated with conventional tillage. These studies indicate that herbicide concentrations observed in these three watersheds were related to crop and soil management practices.
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http://dx.doi.org/10.1016/j.scitotenv.2006.08.023DOI Listing
November 2006

A hybrid active/passive exhaust noise control system for locomotives.

J Acoust Soc Am 2005 Jan;117(1):68-78

BBN Technologies, Cambridge, Massachusetts 02138, USA.

A prototype hybrid system consisting of active and passive components for controlling far-field locomotive exhaust noise has been designed, assembled, and tested on a locomotive. The system consisted of a resistive passive silencer for controlling high-frequency broadband noise and a feedforward multiple-input, multiple-output active control system for suppressing low-frequency tonal noise. The active system used ten roof-mounted bandpass speaker enclosures with 2-12-in. speakers per enclosure as actuators, eight roof-mounted electret microphones as residual sensors, and an optical tachometer that sensed locomotive engine speed as a reference sensor. The system was installed on a passenger locomotive and tested in an operating rail yard. Details of the system are described and the near-field and far-field noise reductions are compared against the design goal.
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http://dx.doi.org/10.1121/1.1836851DOI Listing
January 2005

The role of RNA editing by ADARs in RNAi.

Mol Cell 2002 Oct;10(4):809-17

Department of Biochemistry and Howard Hughes Medical Institute, University of Utah, 20 North 1900 East, Salt Lake City, UT 84132, USA.

Adenosine deaminases that act on RNA (ADARs) are RNA-editing enzymes that deaminate adenosines to create inosines in double-stranded RNA (dsRNA). Here we demonstrate that ADARs are not required for RNA interference (RNAi) and that they do not antagonize the pathway to a detectable level when RNAi is initiated by injecting dsRNA. We find, however, that transgenes expressed in the somatic tissues of wild-type animals are silenced in strains with deletions in the two genes encoding ADARs, adr-1 and adr-2. Transgene-induced gene silencing in adr-1;adr-2 mutants depends on genes required for RNAi, suggesting that a dsRNA intermediate is involved. In wild-type animals we detect edited dsRNA corresponding to transgenes, and we propose that editing of this dsRNA prevents somatic transgenes from initiating RNAi in wild-type animals.
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http://dx.doi.org/10.1016/s1097-2765(02)00649-4DOI Listing
October 2002

Comparison of two methods of fibrescope-guided tracheal intubation.

Br J Anaesth 1991 May;66(5):546-50

Department of Anaesthesia, Selly Oak Hospital, Birmingham.

We have compared intubation time and cardiovascular effects of fibrescope-guided orotracheal intubation aided by the Berman 11 Intubating Airway with those of the tongue traction method of fibreoptic intubation and with conventional Macintosh intubation. We studied 75 patients who received a standard general anaesthetic which included non-depolarizing neuromuscular block; they were allocated randomly to one of the three groups immediately before intubation. The mean time required to effect Berman airway intubation (34.9 s) was similar to that required for tongue traction intubation (35.3 s) and significantly greater than that required for Macintosh intubation (11.7 s). The cardiovascular responses to both types of fibreoptic intubation were significantly greater and more prolonged than those of Macintosh intubation. There were no significant differences between the responses to the two fibreoptic techniques. Haemodynamic effects should be considered when performing fibrescope-guided tracheal intubation under general anaesthesia and, when necessary, appropriate measures should be taken to minimize them.
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http://dx.doi.org/10.1093/bja/66.5.546DOI Listing
May 1991

Cardiovascular effects of fibrescope-guided nasotracheal intubation.

Anaesthesia 1989 Nov;44(11):907-10

Department of Anaesthesia, Selly Oak Hospital, Birmingham.

The cardiovascular effects of fibrescope-guided nasotracheal intubation were compared to those of a control group of patients who were intubated using the Macintosh laryngoscope. The 60 patients studied received a standard anaesthetic technique which included a muscle relaxant and were allocated randomly to one of two groups immediately before tracheal intubation. Systolic and diastolic arterial pressures in the fibreoptic group were significantly lower than in the control group during the first minute after intubation. The maximum increase in diastolic pressure was significantly lower in the fibreoptic group. The heart rate in the fibreoptic group was significantly higher than in the control group during all five minutes after intubation. The maximum increase in heart rate was significantly higher in the fibreoptic group. The cardiovascular responses to fibreoptic nasotracheal intubation under general anaesthesia should not cause undue concern in fit patients, but appropriate measures should be taken to prevent excessive tachycardia in compromised patients.
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http://dx.doi.org/10.1111/j.1365-2044.1989.tb09145.xDOI Listing
November 1989