97 results on '"Walker TW"'
Search Results
2. Optical Techniques for the Determination of Pulsed Laser Damage in Thin Films
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Walker, TW, primary, Guenther, AH, additional, and Nielsen, PE, additional
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3. A Novel Technique for Investigating Impurity Initiated Short Pulse Laser Damage in Thin Films
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Wiggins, TA, primary, Walker, TW, additional, and Guenther, AH, additional
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4. Workshop on Cell-Culture Test Methods
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Brown, SA, primary, Nickel, TD, additional, and Walker, TW, additional
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5. Residual mosquito barrier treatments on U.S. military camouflage netting in a southern California desert environment.
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Britch SC, Linthicum KJ, Wynn WW, Walker TW, Farooq M, Smith VL, Robinson CA, Lothrop BB, Snelling M, Gutierrez A, Lothrop HD, Britch, Seth C, Linthicum, Kenneth J, Wynn, Wayne W, Walker, Todd W, Farooq, Muhammad, Smith, Vincent L, Robinson, Cathy A, Lothrop, Branka B, and Snelling, Melissa
- Abstract
Treating perimeters of vegetation with residual insecticides for protection from mosquito vectors has potential for U.S. military force health protection. However, for current U.S. military operations in hot-arid environments with little or no vegetation, residual applications on portable artificial materials may be a viable alternative. We evaluated bifenthrin residual treatments of U.S. military camouflage netting under hot-arid field conditions in a desert area in southern California exposed to abundant wild Culex tarsalis mosquitoes. We assessed the ability of the treatment to reduce the numbers of mosquitoes penetrating perimeters of netting and reaching CO2-baited mosquito traps. Treated camouflage netting barriers reduced mosquitoes by > or = 50% for 7-14 days and by 20-35% for 21-28 days compared to untreated barriers. Although reductions may be translated into reductions in risk of exposure to mosquito-borne diseases, we emphasize that barrier treatments should be a component in a suite of insect control measures to be effective. [ABSTRACT FROM AUTHOR]
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- 2010
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6. Longitudinal Associations Between Blood Biomarkers and White Matter MRI in Sport-Related Concussion: A Study of the NCAA-DoD CARE Consortium.
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Wu YC, Wen Q, Thukral R, Yang HC, Gill JM, Gao S, Lane KA, Meier TB, Riggen LD, Harezlak J, Giza CC, Goldman J, Guskiewicz KM, Mihalik JP, LaConte SM, Duma SM, Broglio SP, Saykin AJ, McAllister TW, and McCrea MA
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- Humans, Diffusion Tensor Imaging methods, Prospective Studies, Biomarkers, White Matter diagnostic imaging, Athletic Injuries diagnostic imaging, Brain Concussion diagnostic imaging, Football injuries
- Abstract
Background and Objectives: To study longitudinal associations between blood-based neural biomarkers (including total tau, neurofilament light [NfL], glial fibrillary acidic protein [GFAP], and ubiquitin C-terminal hydrolase-L1) and white matter neuroimaging biomarkers in collegiate athletes with sport-related concussion (SRC) from 24 hours postinjury to 1 week after return to play., Methods: We analyzed clinical and imaging data of concussed collegiate athletes in the Concussion Assessment, Research, and Education (CARE) Consortium. The CARE participants completed same-day clinical assessments, blood draws, and diffusion tensor imaging (DTI) at 3 time points: 24-48 hours postinjury, point of becoming asymptomatic, and 7 days after return to play. DTI probabilistic tractography was performed for each participant at each time point to render 27 participant-specific major white matter tracts. The microstructural organization of these tracts was characterized by 4 DTI metrics. Mixed-effects models with random intercepts were applied to test whether white matter microstructural abnormalities are associated with the blood-based biomarkers at the same time point. An interaction model was used to test whether the association varies across time points. A lagged model was used to test whether early blood-based biomarkers predict later microstructural changes., Results: Data from 77 collegiate athletes were included in the following analyses. Among the 4 blood-based biomarkers, total tau had significant associations with the DTI metrics across the 3 time points. In particular, high tau level was associated with high radial diffusivity (RD) in the right corticospinal tract (β = 0.25, SE = 0.07, p
FDR-adjusted = 0.016) and superior thalamic radiation (β = 0.21, SE = 0.07, pFDR-adjusted = 0.042). NfL and GFAP had time-dependent associations with the DTI metrics. NfL showed significant associations only at the asymptomatic time point (|β|s > 0.12, SEs <0.09, p sFDR-adjusted < 0.05) and GFAP showed a significant association only at 7 days after return to play (βs > 0.14, SEs <0.06, p sFDR-adjusted < 0.05). The p values for the associations of early tau and later RD were not significant after multiple comparison adjustment, but were less than 0.1 in 7 white matter tracts., Discussion: This prospective study using data from the CARE Consortium demonstrated that in the early phase of SRC, white matter microstructural integrity detected by DTI neuroimaging was associated with elevated levels of blood-based biomarkers of traumatic brain injury. Total tau in the blood showed the strongest association with white matter microstructural changes., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)- Published
- 2023
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7. Experimental investigation of the performance of anaerobic membrane bioreactor with electrolytic regeneration (AMBER) for challenges and options in wastewater treatment.
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Amouamouha M, Gholikandi GB, and Walker TW
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- Anaerobiosis, Biofuels, Bioreactors, Electrolysis, Membranes, Artificial, Sewage, Waste Disposal, Fluid methods, Wastewater chemistry, Water Purification methods
- Abstract
Significant changes in wastewater services are necessary for achieving the sustainable development goals (SDGs), by utilizing resource recovery, recycle, and reuse in urban wastewater-treatment plants. Based on recent experiences, to improve the filtration behavior of a membrane bioreactor, a hybrid system including an upgraded anaerobic baffled reactor coupled with an electrolysis process and a nanocomposite-membrane was developed. The system, called an anaerobic membrane bioreactor with electrolytic regeneration (AMBER), is a bio-electrochemical process that is expected to be simultaneously efficient in both biogas augmentation and fouling mitigation. The goals were to enhance the stability and efficiency of the anaerobic membrane bioreactor. The integration of the electrolytic process with the ABR (EABR) using a pair of iron electrodes enhanced the removal of contaminants in the ABR while successfully maintained pH in the optimum range for anaerobic digestion (6.8 to 7.2). Then, the performance of AMBER in pollutant removal, including organic load, suspended solids, and microbial load, were investigated over 240 days. The results showed that configuration considerably enhanced permeate flux, as it reduced the deposition of extracellular polymeric substances (EPS) on the surface of the nanocomposite membrane, leading to a reduction in membrane fouling. EPS was extracted and quantified to compare the effect of biogas backwash on the function of the membrane reactor. After 7 d of operation with a daily biogas backwash, the flux reduction was approximately 13 % for the conventional combination of the anaerobic baffled reactor and the membrane bioreactor (AMBR), while it was limited to 4 % in AMBER. After cleaning by the biogas, EPS formation decreased 63 % in AMBER when compared to the AMBR. The results revealed that AMBER can be considered an environmentally competitive bioenergy technology for wastewater treatment with the purpose of water recovery and reuse, employing optimized operational conditions, application of antifouling membranes, and electrically-based strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)
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- 2022
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8. Frugal Imaging Technique of Capillary Flow through Three-Dimensional Polymeric Printing Powders.
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Donovan KJ, Stasiak J, Özbek Ş, Rochefort WE, and Walker TW
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- Powders, Microscopy, Particle Size, Printing, Three-Dimensional, Polymers chemistry
- Abstract
The development of novel imaging techniques of molecular and colloidal transport, including nanoparticles, is an area of active investigation in microfluidic and millifluidic studies. With the advent of three-dimensional (3D) printing, a new domain of materials has emerged, thereby increasing the demand for novel polymers. Specifically, polymeric powders, with average particle sizes on the order of a micron, are experiencing a growing interest from academic and industrial communities. Controlling material tunability at the mesoscopic to microscopic length scales creates opportunities to develop innovative materials, such as gradient materials. Recently, a need for micron-sized polymeric powders has been growing, as clear applications for the material are developing. Three-dimensional printing provides a high-throughput process with a direct link to new applications, driving investigations into the physio-chemical and transport interactions on a mesoscale. The protocol that is discussed in this article provides a non-invasive technique to image fluid flow in packed powder beds, providing high temporal and spatial resolution while leveraging mobile technology that is readily available from mobile devices, such as smartphones. By utilizing a common mobile device, the imaging costs that would normally be associated with an optical microscope are eliminated, resulting in a frugal-science approach. The proposed protocol has successfully characterized a variety of combinations of fluids and powders, creating a diagnostic platform for quickly imaging and identifying an optimal combination of fluid and powder.
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- 2022
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9. Social Support and Loneliness Among Black and Hispanic Senior Women Experiencing Food Insecurity: The Nurse as Primary, Secondary, and Tertiary Intervention.
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Kirkland TW and Woo J
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- Aged, Ethnicity, Female, Food Insecurity, Food Supply, Hispanic or Latino, Humans, Minority Groups, Social Support, Socioeconomic Factors, COVID-19 epidemiology, Loneliness
- Abstract
The impact of social determinants of health (SDOH) is understudied and until recently not a focal point in nursing education. The new Essentials coupled with the impact of the coronavirus (COVID-19) pandemic deem it necessary to address the intersection of SDOH and population health. The impact of COVID 19 disproportionately affects Black and Hispanic families. Couple the disproportionate numbers of COVID 19 among these groups with the growing incidence of food insecurity, and there is a need to explore intersecting links. Emerging research link the lack of social support systems and loneliness to food insecurity. In alignment with addressing competency-based education, it is critical to assess factors such as social support systems and loneliness and the intersection of its effects on such determinants as food insecurity. The article provides an overview for its readers in examining the incidence of food insecurity in older ethnic minority women along with postulated social attributes as contributing factors to the growth rates of food insecurity. The incidence of food insecurity among older ethnic minority women has grown exponentially amid the pandemic. The authors illustrate the role nurses can play in addressing primary, secondary, and tertiary interventions using Neuman's Theory. The intervention pathways are delineated through the lens of nursing theoretic framework created by Betty Neuman Systems Model., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2022 Elsevier Inc. All rights reserved.)
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- 2022
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10. Spatial Repellents Protect Small Perimeters from Riceland Mosquitoes in a Warm-Humid Environment.
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Britch SC, Dame DA, Meisch MV, Kline DL, Walker TW, Allan SA, Urban J, Aldridge RL, and Linthicum KJ
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- Animals, Environment, Female, Acyclic Monoterpenes, Allethrins, Culicidae, Cyclopropanes, Fluorobenzenes, Insect Repellents
- Abstract
Recent experiments suggest spatial repellents may significantly reduce biting pressure from host-seeking riceland mosquitoes, such as Anopheles quadrimaculatus, in a warm-humid open-field habitat. However, little is known regarding efficacy of these formulations in partially enclosed spaces where US military personnel may be sheltered or concealed in an operational environment. In this study we investigated the capability of 3 spatial repellents-metofluthrin, linalool, and d-cis/trans allethrin-to reduce mosquito incursion into small open-top enclosures of US military camouflage netting. We found that metofluthrin was more effective in partially enclosed spaces compared with the open field, whereas both linalool and d-cis/trans allethrin provided superior protection in the open. These findings support strategic selection of spatial repellents depending on the environment immediately surrounding the host., (Copyright © 2021 by The American Mosquito Control Association, Inc.)
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- 2021
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11. Recycling of multilayer plastic packaging materials by solvent-targeted recovery and precipitation.
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Walker TW, Frelka N, Shen Z, Chew AK, Banick J, Grey S, Kim MS, Dumesic JA, Van Lehn RC, and Huber GW
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Many plastic packaging materials manufactured today are composites made of distinct polymer layers (i.e., multilayer films). Billions of pounds of these multilayer films are produced annually, but manufacturing inefficiencies result in large, corresponding postindustrial waste streams. Although relatively clean (as opposed to municipal wastes) and of near-constant composition, no commercially practiced technologies exist to fully deconstruct postindustrial multilayer film wastes into pure, recyclable polymers. Here, we demonstrate a unique strategy we call solvent-targeted recovery and precipitation (STRAP) to deconstruct multilayer films into their constituent resins using a series of solvent washes that are guided by thermodynamic calculations of polymer solubility. We show that the STRAP process is able to separate three representative polymers (polyethylene, ethylene vinyl alcohol, and polyethylene terephthalate) from a commercially available multilayer film with nearly 100% material efficiency, affording recyclable resins that are cost-competitive with the corresponding virgin materials., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)
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- 2020
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12. 'Bubble sign': gas-forming bacteria from an odontogenic infection.
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Richards C, Walker TW, Girgis S, and Colbert S
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- Abscess drug therapy, Abscess etiology, Abscess surgery, Dental Caries diagnostic imaging, Female, Humans, Middle Aged, Radiography, Panoramic, Sepsis diagnosis, Tooth Extraction, Dental Caries complications, Emphysema etiology, Focal Infection, Dental complications, Sepsis etiology
- Abstract
Competing Interests: Competing interests: None declared.
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- 2020
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13. Solid-state NMR studies of solvent-mediated, acid-catalyzed woody biomass pre-treatment for enzymatic conversion of residual cellulose.
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Walker TW, Kuch N, Vander Meulen KA, Clewett CFM, Huber GW, Fox BG, and Dumesic JA
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Enzymes selectively hydrolyze the carbohydrate fractions of lignocellulosic biomass into corresponding sugars, but these processes are limited by low yields and slow catalytic turnovers. Under certain conditions, the rates and yields of enzymatic sugar production can be increased by pretreating biomass using solvents, heat and dilute acid catalysts. However, the mechanistic details underlying this behavior are not fully elucidated, and designing effective pretreatment strategies remains an empirical challenge. Herein, using a combination of solid-state and high-resolution magic-angle-spinning NMR, infrared spectroscopy and X-ray diffractometry, we show that the extent to which cellulase enzymes are able to hydrolyze solvent-pretreated biomass can be understood in terms of the ability of the solvent to break the chemical linkages between cellulose and non-cellulosic materials in the cell wall. This finding is of general significance to enzymatic biomass conversion research, and implications for designing improved biomass conversion strategies are discussed. These findings demonstrate the utility of solid-state NMR as a tool to elucidate the key chemical and physical changes that occur during the liquid-phase conversion of real biomass.
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- 2020
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14. QuitSMART Utah: an implementation study protocol for a cluster-randomized, multi-level Sequential Multiple Assignment Randomized Trial to increase Reach and Impact of tobacco cessation treatment in Community Health Centers.
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Fernandez ME, Schlechter CR, Del Fiol G, Gibson B, Kawamoto K, Siaperas T, Pruhs A, Greene T, Nahum-Shani I, Schulthies S, Nelson M, Bohner C, Kramer H, Borbolla D, Austin S, Weir C, Walker TW, Lam CY, and Wetter DW
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- Basic Helix-Loop-Helix Transcription Factors, Drosophila Proteins, Health Behavior, Humans, Implementation Science, Inservice Training organization & administration, Program Development, Socioeconomic Factors, Text Messaging, Tobacco Use Cessation Devices, Utah, Community Health Centers organization & administration, Electronic Health Records organization & administration, Hotlines organization & administration, Primary Health Care organization & administration, Tobacco Use Cessation methods
- Abstract
Background: Tobacco use remains the leading cause of death and disability in the USA and is disproportionately concentrated among low socioeconomic status (SES) populations. Community Health Centers (CHCs) are a key venue for reaching low SES populations with evidence-based tobacco cessation treatment such as Quitlines. Electronic health record (EHR)-based interventions at the point-of-care, text messaging (TM), and phone counseling have the potential to increase Quitline reach and are feasible to implement within CHCs. However, there is a lack of data to inform how, when, and in what combination these strategies should be implemented. The aims of this cluster-randomized trial are to evaluate multi-level implementation strategies to increase the Reach (i.e., proportion of tobacco-using patients who enroll in the Quitline) and Impact (i.e., Reach × Efficacy [efficacy is defined as the proportion of tobacco-using patients who enroll in Quitline treatment that successfully quit]) and to evaluate characteristics of healthcare system, providers, and patients that may influence tobacco-use outcomes., Methods: This study is a multilevel, three-phase, Sequential Multiple Assignment Randomized Trial (SMART), conducted in CHCs (N = 33 clinics; N = 6000 patients). In the first phase, clinics will be randomized to two different EHR conditions. The second and third phases are patient-level randomizations based on prior treatment response. Patients who enroll in the Quitline receive no further interventions. In phase two, patients who are non-responders (i.e., patients who do not enroll in Quitline) will be randomized to receive either TM or continued-EHR. In phase three, patients in the TM condition who are non-responders will be randomized to receive either continued-TM or TM + phone coaching., Discussion: This project will evaluate scalable, multi-level interventions to directly address strategic national priorities for reducing tobacco use and related disparities by increasing the Reach and Impact of evidence-based tobacco cessation interventions in low SES populations., Trial Registration: This trial was registered at ClinicalTrials.gov (NCT03900767) on April 4th, 2019.
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- 2020
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15. Visualizing Efficacy of Pesticides Against Disease Vector Mosquitoes in the Field.
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Britch SC, Linthicum KJ, Aldridge RL, Golden FV, and Walker TW
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- Animals, Desert Climate, Culicidae drug effects, Disease Vectors, Mosquito Vectors drug effects, Pesticides toxicity
- Abstract
Efficacy of public health pesticides targeting nuisance and disease-vector insects such as mosquitoes, sand flies, and filth-breeding flies is not uniform across ecological zones. To best protect public and veterinary health from these insects, the environmental limitations of pesticides need to be investigated to inform effective use of the most appropriate pesticide formulations and techniques. We have developed a research program to evaluate combinations of pesticides, pesticide application equipment, and application techniques in hot-arid desert, hot-humid tropical, warm and cool temperate, and urban locations to derive pesticide use guidelines specific to target insect and environment. To these ends we designed a system of protocols to support efficient, cost-effective, portable, and standardized evaluation of a diverse range of pesticides and equipment across multiple environments. At the core of these protocols is the use of an array of small cages with colony-reared sentinel mosquitoes (adults and immatures) and sand flies (adults), strategically arranged in natural habitats and exposed to pesticide spray. Spatial and temporal patterns of pesticide efficacy are derived from percent mortality in sentinel cages, then mapped and visualized in a geographic information system. Maps of sentinel mortality data may be statistically compared to evaluate relative efficacy of a pesticide across multiple environments, or to study multiple pesticides in a single environment. Protocols may be modified to accommodate a variety of scenarios, including, for example, the vertical orientation of sentinels in canopy habitats or simultaneous testing of ground and aerial application methods.
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- 2019
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16. Effects of chloride ions in acid-catalyzed biomass dehydration reactions in polar aprotic solvents.
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Mellmer MA, Sanpitakseree C, Demir B, Ma K, Elliott WA, Bai P, Johnson RL, Walker TW, Shanks BH, Rioux RM, Neurock M, and Dumesic JA
- Abstract
The use of polar aprotic solvents in acid-catalyzed biomass conversion reactions can lead to improved reaction rates and selectivities. We show that further increases in catalyst performance in polar aprotic solvents can be achieved through the addition of inorganic salts, specifically chlorides. Reaction kinetics studies of the Brønsted acid-catalyzed dehydration of fructose to hydroxymethylfurfural (HMF) show that the use of catalytic concentrations of chloride salts leads to a 10-fold increase in reactivity. Furthermore, increased HMF yields can be achieved using polar aprotic solvents mixed with chlorides. Ab initio molecular dynamics simulations (AIMD) show that highly localized negative charge on Cl
- allows the chloride anion to more readily approach and stabilize the oxocarbenium ion that forms and the deprotonation transition state. High concentrations of polar aprotic solvents form local hydrophilic environments near the reactive hydroxyl group which stabilize both the proton and chloride anions and promote the dehydration of fructose.- Published
- 2019
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17. Residual Pesticide On Hesco ® Blast Protection Wall In Temperate Florida Habitat Effective Against Mosquitoes, Stable Flies, and Sand Flies.
- Author
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Britch SC, Linthicum KJ, Aldridge RL, Walker TW, Rush MJE, Aubuchon MD, and Kerce JD
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- Animals, Florida, Houseflies, Insecticides, Mosquito Control, Culex, Insect Control, Muscidae, Nitriles, Pesticide Residues, Phlebotomus, Pyrethrins
- Abstract
United States military troops in the field are exposed to the environment and are thus at high risk for transmission of arboviruses, and degradation of mission from continual harassment from insects. Passive vector control, such as application of residual insecticides to US military materials common in the field such as tents and camouflage netting, has been shown to be effective and can contribute to a successful integrated vector management (IVM) plan in the field to reduce this risk. However, other common US military field materials have not been evaluated with residual pesticides. In this study we conducted the first known investigation of the efficacy and longevity of a residual pesticide containing λ-cyhalothrin applied to HESCO
® blast protection wall geotextile. We exposed treated material to a temperate Florida environment and found that this treatment can be effective against sand flies, filth-breeding flies, and mosquitoes for at least 6 wk. This study provides evidence that residual treatment of this US military material may be leveraged as an IVM component to enhance the US Department of Defense pest management system.- Published
- 2018
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18. Effects of truck-mounted, ultra low volume mosquito adulticides on honey bees (Apis mellifera) in a suburban field setting.
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Pokhrel V, DeLisi NA, Danka RG, Walker TW, Ottea JA, and Healy KB
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- Animals, Bees enzymology, Bees growth & development, Esterases metabolism, Gene Expression Regulation, Enzymologic drug effects, Glutathione Transferase metabolism, Inactivation, Metabolic, Insect Proteins metabolism, Motor Vehicles, Nitriles toxicity, Bees drug effects, Insecticides toxicity, Mosquito Control instrumentation, Pyrethrins toxicity
- Abstract
Few studies have examined the impact of mosquito adulticides on honey bees under conditions that reflect actual field exposure. Whereas several studies have evaluated the toxicity of mosquito control products on honey bees, most have been laboratory based and have focused solely on acute mortality as a measure of impact. The goal of this study was to determine effects of routine applications of truck-based ultra-low volume (ULV) mosquito adulticides (i.e., Scourge, Duet, and Deltagard) on honey bees in a suburban setting. The mosquito adulticides used in this study were pyrethroids with active ingredients resmethrin (Scourge), prallethrin and sumithrin (Duet), and deltamethrin (Deltagard), in which resmethrin, prallethrin, and sumithrin were synergized with piperonyl butoxide. We measured and compared mortality and detoxification enzyme activities (esterase and glutathione S-transferase) from sentinel beehives within and outside of mosquito control areas. Concurrently, colony health (i.e., number of adult bees, brood quantity and brood quality) was compared throughout the study period. No significant differences were observed in honey bee mortality, colony health or detoxification enzyme activities between treated (five sprayed areas each received one to three insecticide treatment) and control sites (four unsprayed areas that did not receive insecticide treatment) over the seven week study period. However, our laboratory study showed that exposure to resmethrin, the active ingredient in Scourge, caused significant inhibition of esterase activity compared with the control group. Our findings suggest that proper application of truck based insecticides for mosquito control results in little or no exposure and therefore minimal effects on domestic honey bees.
- Published
- 2018
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19. Evaluation of the long-term efficacy of K-Othrine ® PolyZone on three surfaces against laboratory reared Anopheles gambiae in semi-field conditions.
- Author
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Dunford JC, Estep AS, Waits CM, Richardson AG, Hoel DF, Horn K, Walker TW, Blersch JS, Kerce JD, and Wirtz RA
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- Animals, Biological Assay, Drug Interactions, Florida, Georgia, Survival Analysis, Anopheles drug effects, Anopheles growth & development, Construction Materials, Insecticides pharmacology, Nitriles pharmacology, Pyrethrins pharmacology
- Abstract
Background: In this semi-field study, a new polymer-enhanced deltamethrin formulation, K-Othrine
® PolyZone, was compared to a standard deltamethrin product for residual activity against a susceptible strain of laboratory-reared Anopheles gambiae using standard WHO cone bioassays., Methods: Residual insecticide efficacy was recorded after exposure to metal, cement and wood panels maintained in experimental huts in sub-tropical environmental conditions in north central Florida, USA, and panels stored in a climate controlled chamber located at the Centers for Disease Control and Prevention, Georgia, USA., Conclusions: K-Othrine® PolyZone demonstrated 100% control on metal and cement panels 1 year post application and > 80% control on wood panels up to 6 mo. The new formulation should be considered for use in indoor residual spray programmes requiring long-term control of malaria vectors.- Published
- 2018
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20. Reduced biomass burning emissions reconcile conflicting estimates of the post-2006 atmospheric methane budget.
- Author
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Worden JR, Bloom AA, Pandey S, Jiang Z, Worden HM, Walker TW, Houweling S, and Röckmann T
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Several viable but conflicting explanations have been proposed to explain the recent ~8 p.p.b. per year increase in atmospheric methane after 2006, equivalent to net emissions increase of ~25 Tg CH
4 per year. A concurrent increase in atmospheric ethane implicates a fossil source; a concurrent decrease in the heavy isotope content of methane points toward a biogenic source, while other studies propose a decrease in the chemical sink (OH). Here we show that biomass burning emissions of methane decreased by 3.7 (±1.4) Tg CH4 per year from the 2001-2007 to the 2008-2014 time periods using satellite measurements of CO and CH4 , nearly twice the decrease expected from prior estimates. After updating both the total and isotopic budgets for atmospheric methane with these revised biomass burning emissions (and assuming no change to the chemical sink), we find that fossil fuels contribute between 12-19 Tg CH4 per year to the recent atmospheric methane increase, thus reconciling the isotopic- and ethane-based results.- Published
- 2017
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21. Psychometric characteristics of the MATRICS Consensus Cognitive Battery in a large pooled cohort of stable schizophrenia patients.
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Georgiades A, Davis VG, Atkins AS, Khan A, Walker TW, Loebel A, Haig G, Hilt DC, Dunayevich E, Umbricht D, Sand M, and Keefe RSE
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- Adult, Age Factors, Computer Simulation, Female, Humans, Male, Psychometrics, Regression Analysis, Reproducibility of Results, Sex Factors, Cognition, Neuropsychological Tests, Schizophrenia diagnosis, Schizophrenic Psychology
- Abstract
The MATRICS Consensus Cognitive Battery (MCCB) was developed to assess cognitive treatment effects in schizophrenia clinical trials, and is considered the FDA gold standard outcome measure for that purpose. The aim of the present study was to establish pre-treatment psychometric characteristics of the MCCB in a large pooled sample. The dataset included 2616 stable schizophrenia patients enrolled in 15 different clinical trials between 2007 and 2016 within the United States (94%) and Canada (6%). The MCCB was administered twice prior to the initiation of treatment in 1908 patients. Test-retest reliability and practice effects of the cognitive composite score, the neurocognitive composite score, which excludes the domain Social Cognition, and the subtests/domains were examined using Intra-Class Correlations (ICC) and Cohen's d. Simulated regression models explored which domains explained the greatest portion of variance in composite scores. Test-retest reliability was high (ICC=0.88) for both composite scores. Practice effects were small for the cognitive (d=0.15) and neurocognitive (d=0.17) composites. Simulated bootstrap regression analyses revealed that 3 of the 7 domains explained 86% of the variance for both composite scores. The domains that entered most frequently in the top 3 positions of the regression models were Speed of Processing, Working Memory, and Visual Learning. Findings provide definitive psychometric characteristics and a benchmark comparison for clinical trials using the MCCB. The test-retest reliability of the MCCB composite scores is considered excellent and the learning effects are small, fulfilling two of the key criteria for outcome measures in cognition clinical trials., (Copyright © 2017 Elsevier B.V. All rights reserved.)
- Published
- 2017
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22. Limited impacts of truck-based ultra-low-volume applications of mosquito adulticides on mortality in honey bees (Apis mellifera).
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Rinkevich FD, Margotta JW, Pokhrel V, Walker TW, Vaeth RH, Hoffman WC, Fritz BK, Danka RG, Rinderer TE, Aldridge RL, Linthicum KJ, Ottea JA, and Healy KB
- Subjects
- Animals, Culex, Female, Toxicity Tests, Bees, Insecticides administration & dosage, Mosquito Control
- Abstract
Adulticides applied against mosquitoes can reduce vector populations during times of high arbovirus transmission. However, impacts of these insecticides on pollinators and other non-target organisms are of concern to mosquito control professionals, beekeepers and others. We evaluated mortality of Culex quinquefasciatus and Apis mellifera when caged insects were exposed to low and high label rates of four common adulticides (Aqua-Pursuit™ [permethrin], Duet® [prallethrin + sumithrin], Fyfanon® [malathion] and Scourge® [resmethrin]) at six distances up to 91.4 m from a truck-mounted ultra-low-volume sprayer. Honey bee mortality was both absolutely low (61 m had limited impacts on honey bee mortality while providing effective mosquito control.
- Published
- 2017
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23. Differential Roles for the Coagulation Factors XI and XII in Regulating the Physical Biology of Fibrin.
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Sylman JL, Daalkhaijav U, Zhang Y, Gray EM, Farhang PA, Chu TT, Zilberman-Rudenko J, Puy C, Tucker EI, Smith SA, Morrissey JH, Walker TW, Nan XL, Gruber A, and McCarty OJT
- Subjects
- Humans, Polyphosphates chemistry, Blood Coagulation Factor Inhibitors chemistry, Factor XI antagonists & inhibitors, Factor XI chemistry, Factor XII antagonists & inhibitors, Factor XII chemistry, Fibrin chemistry, Fibrinolysis
- Abstract
In the contact activation pathway of the coagulation, zymogen factor XII (FXII) is converted to FXIIa, which triggers activation of FXI leading to the activation of FIX and subsequent thrombin generation and fibrin formation. Feedback activation of FXI by thrombin has been shown to promote thrombin generation in a FXII-independent manner and FXIIa can bypass FXI to directly activate FX and prothrombin in the presence of highly negatively charged molecules, such as long-chain polyphosphates (LC polyP). We sought to determine whether activation of FXII or FXI differentially regulate the physical biology of fibrin formation. Fibrin formation was initiated with tissue factor, ellagic acid (EA), or LC polyP in the presence of inhibitors of FXI and FXII. Our data demonstrated that inhibition of FXI decreased the rate of fibrin formation and fiber network density, and increased the fibrin network strength and rate of fibrinolysis when gelation was initiated via the contact activation pathway with EA. FXII inhibition decreased the fibrin formation and fibrin density, and increased the fibrinolysis rate only when fibrin formation was initiated via the contact activation pathway with LC polyP. Overall, we demonstrate that inhibition of FXI and FXII distinctly alter the biophysical properties of fibrin.
- Published
- 2017
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- View/download PDF
24. Kinetics of Levoglucosenone Isomerization.
- Author
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Krishna SH, Walker TW, Dumesic JA, and Huber GW
- Subjects
- Furaldehyde analogs & derivatives, Furaldehyde chemistry, Glucose chemistry, Isomerism, Kinetics, Models, Chemical, Sulfuric Acids chemistry, Temperature, Water chemistry, Bridged Bicyclo Compounds, Heterocyclic chemistry, Glucose analogs & derivatives
- Abstract
We studied the acid-catalyzed isomerization of levoglucosenone (LGO) to 5-hydroxymethylfurfural (HMF) and developed a reaction kinetics model that describes the experimental data across a range of conditions (100-150 °C, 50-100 mm H
2 SO4 , 50-150 mm LGO). LGO and its hydrated derivative exist in equilibrium under these reaction conditions. Thermal and catalytic degradation of HMF are the major sources of carbon loss. Within the range of conditions studied, higher temperatures and shorter reaction times favor the production of HMF. The yields of HMF and levulinic acid decrease monotonically as tetrahydrofuran is added to the aqueous solvent system, indicating that water plays a role in the LGO isomerization reaction. Initial-rate analyses show that HMF is produced solely from LGO rather than from the hydrated derivative of LGO. The results of this study are consistent with a mechanism for LGO isomerization that proceeds through hydration of the anhydro bridge, followed by ring rearrangement analogous to the isomerization of glucose to fructose., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2017
- Full Text
- View/download PDF
25. The Olympic legacy: Journal metrics in sports medicine and dentistry.
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Thomas J, Walker TW, Miller S, Cobb A, and Thomas SJ
- Abstract
Systematic analysis of integral aspects within sport enables improvement in performance. One key aspect is the management and prevention of injuries. Bibliometrics is a systematic method for evaluating research output. It may be expected that the quantity and quality of sports injury research over time may strongly correlate with the timing of the Olympic games. This study was conducted to determine the effect of the Olympic legacy on academic sports medicine and evidence to prevent injuries of the face and teeth. A literature search within the PubMed database was undertaken to identify the quantity of literature published annually between 1996 and 2015 in the fields of sports injuries and injury prevention. The top 5 journals publishing in each field were then identified and the change in their impact factor (IF) was investigated. It was seen that, since 1996, there has been an overall increase in the quantity of literature published regarding sports injuries and prevention of sports injuries of 209% and 217%, respectively. Publications regarding facial injuries and dental injuries within sport show an increase of 114% and 71%, respectively. There was an increase in IF since 2000 in almost every journal investigated. A strong, positive correlation is seen among journals publishing on the prevention of sports injuries, showing a median IF increase of 2.8198. No statistical significance was found between Olympic years and the number of publications. Hence, there has been a gradual increase in both the quality and quantity of publications regarding sports injuries since 1996. However, there appears to be no immediate added effect of the "Olympic legacy" following each Olympic games on the quantity or quality of publications in these fields., Competing Interests: There are no conflicts of interest
- Published
- 2016
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26. Nanoscale Patterning of Extracellular Matrix Alters Endothelial Function under Shear Stress.
- Author
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Nakayama KH, Surya VN, Gole M, Walker TW, Yang W, Lai ES, Ostrowski MA, Fuller GG, Dunn AR, and Huang NF
- Subjects
- Blood Vessels chemistry, Cell Movement, Cell Proliferation, Collagen chemistry, Endothelial Cells metabolism, Extracellular Matrix metabolism, Humans, Nanofibers chemistry, Tissue Engineering, Cell Tracking, Endothelial Cells chemistry, Extracellular Matrix chemistry, Stress, Mechanical
- Abstract
The role of nanotopographical extracellular matrix (ECM) cues in vascular endothelial cell (EC) organization and function is not well-understood, despite the composition of nano- to microscale fibrillar ECMs within blood vessels. Instead, the predominant modulator of EC organization and function is traditionally thought to be hemodynamic shear stress, in which uniform shear stress induces parallel-alignment of ECs with anti-inflammatory function, whereas disturbed flow induces a disorganized configuration with pro-inflammatory function. Since shear stress acts on ECs by applying a mechanical force concomitant with inducing spatial patterning of the cells, we sought to decouple the effects of shear stress using parallel-aligned nanofibrillar collagen films that induce parallel EC alignment prior to stimulation with disturbed flow resulting from spatial wall shear stress gradients. Using real time live-cell imaging, we tracked the alignment, migration trajectories, proliferation, and anti-inflammatory behavior of ECs when they were cultured on parallel-aligned or randomly oriented nanofibrillar films. Intriguingly, ECs cultured on aligned nanofibrillar films remained well-aligned and migrated predominantly along the direction of aligned nanofibrils, despite exposure to shear stress orthogonal to the direction of the aligned nanofibrils. Furthermore, in stark contrast to ECs cultured on randomly oriented films, ECs on aligned nanofibrillar films exposed to disturbed flow had significantly reduced inflammation and proliferation, while maintaining intact intercellular junctions. This work reveals fundamental insights into the importance of nanoscale ECM interactions in the maintenance of endothelial function. Importantly, it provides new insight into how ECs respond to opposing cues derived from nanotopography and mechanical shear force and has strong implications in the design of polymeric conduits and bioengineered tissues.
- Published
- 2016
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27. Deposition from Ultra-Low Volume Application of Public Health Insecticides in a Hot Desert Environment.
- Author
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Fisher ML, Hoel DF, Farooq M, and Walker TW
- Subjects
- Animals, Humans, Insecticides administration & dosage, Insecticides pharmacology, Kuwait, Malathion administration & dosage, Malathion chemistry, Malathion pharmacology, Nebulizers and Vaporizers, Pesticide Residues, Petroleum, Pyrethrins administration & dosage, Pyrethrins chemistry, Pyrethrins pharmacology, Desert Climate, Insect Control methods, Insecticides chemistry, Psychodidae drug effects, Public Health
- Abstract
Three insecticides commonly used for mosquito and sand fly control were applied 30 min to 3 h after sunset during June and July 2010, at Camp Buehring, Kuwait, to determine the relative quantity of pesticides to height and distance traveled in a hot desert environment. A BVA dilution oil was used for the control. Oil-based adulticides were sprayed using a truck-mounted Curtis DynaFog Maxi-Pro 4 ultra-low volume (ULV) sprayer. Malathion (Fyfanon ULV, 96% active ingredient [AI]), resmethrin (Scourge 4+12, 4% AI), pyrethrins (ULD BP-300, 3% AI), and BVA Spray 13 (100% refined petroleum distillate) were mixed with Uvitex optical brightener fluorescent dye and applied at 2 speeds on evenings when wind speed was less than 16.1 km/h (10 mph). Collection targets using biodegradable cotton ribbons (1 m×2.5 cm) were later read with a fluorometer to quantify the amount of insecticide deposited on targets set at heights of 15.2, 76.2, and 152.4 cm (6, 30, and 60 in.) and distances of 1.5, 6.1, 15.2, 30.5, 61.0, and 91.4 m (5, 20, 50, 100, 200, and 300 ft). Mean insecticide deposition across all distances was 31% on 76.2-cm targets and 49% on 152.4-cm targets, while 15.2-cm targets typically collected <20% of test spray. Mean ground temperatures were typically within 5°C of air temperatures at 152.4 cm and within 1 to 5°C of air at 15.2 cm or 76.2 cm. Collectively, mean insecticide deposition was 80% at or above 76.2 cm for all insecticides. This finding may explain in part why control of low-flying phlebotomine sand flies with ULV insecticides has been met with less than optimal success by US military forces deployed in the Middle East.
- Published
- 2015
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28. Oral surgery: Suturing in the real world.
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French K, Sonde N, Perry R, and Walker TW
- Subjects
- Humans, Oral Surgical Procedures methods, Oral Surgical Procedures education, Suture Techniques education
- Published
- 2015
- Full Text
- View/download PDF
29. Public health nurses strive to keep community safe, healthy.
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Campbell LA and Linderman TW
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Patient Safety, United States, Health Promotion methods, Nurse's Role, Nurses, Public Health psychology, Patient Education as Topic, Public Health Nursing organization & administration, Tobacco Use prevention & control
- Published
- 2015
30. SR450 And Superhawk XP Applications Of Bacillus thuringiensis israelensis Against Culex quinquefasciatus.
- Author
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Dunford JC, Stoops CA, Estep AS, Britch SC, Richardson AG, Walker TW, Farooq M, Hoel DF, Platt RR, Smith VL, Wirtz RA, and Kerce JD
- Subjects
- Animals, Culex growth & development, Florida, Larva growth & development, Larva microbiology, Mosquito Control instrumentation, Pest Control, Biological instrumentation, Bacillus thuringiensis pathogenicity, Culex microbiology, Mosquito Control methods, Pest Control, Biological methods
- Abstract
Sprayer comparisons and larval morality assays were conducted following SR450 backpack mist blower and Superhawk XP thermal fogger applications of Vectobac® WDG Bacillus thuringiensis israelensis (Bti) against Culex quinquefasciatus. Bacillus thuringiensis israelensis was applied at maximum label rate in a 232.26-m(2) field plot located in north-central Florida with containers placed at 2 heights (ground level and 1.52 m above ground) on stakes positioned 3.04, 6.09, 9.14, 12.19, and 15.24 m from the spray line. Results indicated that there was no significant (P > 0.05) difference in 24- and 48-h larval mortality between the 2 sprayers or between the 2 heights. There was significant difference (P < 0.05) among the 5 rows, with mortality continuously decreasing with increasing distance from sprayer. Both sprayers provided on average >70% larval mortality 3.04-9.14 m from the spray line, and <60% mortality at 12.19 and 15.24 m. The data suggest that the SR450 and Superhawk XP may be comparable sprayers for use with Bti to control mosquito larvae.
- Published
- 2014
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31. Healing efficacy of sea buckthorn (Hippophae rhamnoides L.) seed oil in an ovine burn wound model.
- Author
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Ito H, Asmussen S, Traber DL, Cox RA, Hawkins HK, Connelly R, Traber LD, Walker TW, Malgerud E, Sakurai H, and Enkhbaatar P
- Subjects
- Animals, Burns diagnostic imaging, Debridement, Disease Models, Animal, Laser-Doppler Flowmetry, Seeds, Sheep, Domestic, Transplantation, Autologous, Ultrasonography, Burns surgery, Hippophae, Phytotherapy, Plant Oils pharmacology, Skin Transplantation methods, Wound Healing drug effects
- Abstract
To investigate the efficacy of sea buckthorn (SBT) seed oil - a rich source of substances known to have anti-atherogenic and cardioprotective activity, and to promote skin and mucosa epithelization - on burn wound healing, five adult sheep were subjected to 3rd degree flame burns. Two burn sites were made on the dorsum of the sheep and the eschar was excised down to the fascia. Split-thickness skin grafts were harvested, meshed, and fitted to the wounds. The autograft was placed on the fascia and SBT seed oil was topically applied to one recipient and one donor site, respectively, with the remaining sites treated with vehicle. The wound blood flow (LASER Doppler), and epithelization (ultrasound) were determined at 6, 14, and 21 days after injury. 14 days after grafting, the percentage of epithelization in the treated sites was greater (95 ± 2.2% vs. 83 ± 2.9%, p<0.05) than in the untreated sites. Complete epithelization time was shorter in both treated recipient and donor sites (14.20 ± 0.48 vs. 19.60 ± 0.40 days, p<0.05 and 13.40 ± 1.02 vs. 19.60 ± 0.50 days, p<0.05, respectively) than in the untreated sites, confirmed by ultrasound. In conclusion, SBT seed oil has significant wound healing activity in full-thickness burns and split-thickness harvested wounds., (Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
32. Shoulder injuries among US high school athletes, 2005/2006-2011/2012.
- Author
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Robinson TW, Corlette J, Collins CL, and Comstock RD
- Subjects
- Adolescent, Female, Humans, Male, Schools, Time Factors, Athletic Injuries epidemiology, Shoulder Injuries
- Abstract
Objectives: The objective of this study was to describe shoulder injuries in a nationally representative sample of high school athletes playing 9 sports. A national estimate of shoulder injuries among high school athletes was subsequently calculated., Methods: Injury data were collected in 9 sports (boys' football, soccer, basketball, wrestling, and baseball; girls' soccer, volleyball, basketball, and softball) during the 2005-2006 through 2011-2012 academic years from a nationally representative sample of high schools via High School Reporting Information Online., Results: During the 2005-2006 through 2011-2012 academic years, high school athletes in this study sustained 2798 shoulder injuries during 13,002,321 athlete exposures, for an injury rate of 2.15 per 10,000 athlete exposures. This corresponds to a nationally estimated 820,691 injuries during this time period. Rates of injury were higher in competition as compared with practice (rate ratio = 3.17 [95% confidence interval: 2.94-3.41]). The highest rate of injury was in football (4.86) and the lowest in girls' soccer (0.42). The most common types of injury were strain/sprain (37.9%) and dislocation/separation (29.2%). Boys were more likely than girls to sustain their injuries after contact with another person or with the playing surface. Surgical repair was required for 7.9% of the injuries. Time loss from athletic participation varied among sports, with 40.7% of athletes returning within 1 week, whereas 8.2% were medically disqualified for their season/career., Conclusions: High school shoulder injury rates and patterns varied by sport and gender. Prospective epidemiologic surveillance is warranted to discern trends and patterns to develop evidence-based interventions to prevent shoulder injuries.
- Published
- 2014
- Full Text
- View/download PDF
33. Microvascular endothelial cells migrate upstream and align against the shear stress field created by impinging flow.
- Author
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Ostrowski MA, Huang NF, Walker TW, Verwijlen T, Poplawski C, Khoo AS, Cooke JP, Fuller GG, and Dunn AR
- Subjects
- Finite Element Analysis, Humans, Molecular Imaging, Cell Movement, Human Umbilical Vein Endothelial Cells cytology, Hydrodynamics, Materials Testing instrumentation, Microvessels cytology, Stress, Mechanical
- Abstract
At present, little is known about how endothelial cells respond to spatial variations in fluid shear stress such as those that occur locally during embryonic development, at heart valve leaflets, and at sites of aneurysm formation. We built an impinging flow device that exposes endothelial cells to gradients of shear stress. Using this device, we investigated the response of microvascular endothelial cells to shear-stress gradients that ranged from 0 to a peak shear stress of 9-210 dyn/cm(2). We observe that at high confluency, these cells migrate against the direction of fluid flow and concentrate in the region of maximum wall shear stress, whereas low-density microvascular endothelial cells that lack cell-cell contacts migrate in the flow direction. In addition, the cells align parallel to the flow at low wall shear stresses but orient perpendicularly to the flow direction above a critical threshold in local wall shear stress. Our observations suggest that endothelial cells are exquisitely sensitive to both magnitude and spatial gradients in wall shear stress. The impinging flow device provides a, to our knowledge, novel means to study endothelial cell migration and polarization in response to gradients in physical forces such as wall shear stress., (Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
34. Temporal and storage effects on ultra-low volume droplets of insecticides collected on Teflon-coated slides.
- Author
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Farooq M, Lloyd AM, Estep AS, Walker TW, and Hughes T
- Subjects
- Drug Storage, Insecticides chemistry, Polytetrafluoroethylene, Temperature, Insecticides administration & dosage
- Abstract
Use of microscope slides is the most commonly used method to field-assess the droplet spectrum of ultra-low volume (ULV) sprays. Due to absence of analysis facilities during military deployments, slides must be stored and shipped, and the impact of delays in processing and storage conditions on droplets is unknown. This study was designed to evaluate the effect of storage temperatures and duration on droplets on Teflon-coated slides. Treatments included BVA-13 mineral oil, Kontrol 30-30 (30% permethrin), and Fyfanon (96.5% malathion), 2 slide wrapping techniques (proper and improper), and 2 storage temperatures (23 and 45 degrees C), replicated 6 times. The same areas of a slide were measured at different times for 56-58 days using the DropVision droplet measurement system. Regardless of the wrapping technique, droplets of BVA-13, Fyfanon, and Kontrol 30-30 on slides stored at 45 degrees C reduced significantly after 1, 2, and 1 day, respectively, but droplets on slides stored at 23 degrees C were not significantly affected. The results of this study may assist vector control professionals to accurately interpret the droplet size and help in the effective dispersal of ULV-applied insecticides.
- Published
- 2013
- Full Text
- View/download PDF
35. Academic background of oral and maxillofacial specialty trainees in the United Kingdom.
- Author
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Walker TW, Tahim AS, Lau CK, Nyunt T, and Magennis P
- Subjects
- Achievement, Adult, Career Choice, Educational Status, Female, Humans, Male, Middle Aged, Publications, Surveys and Questionnaires, United Kingdom, Students, Dental, Surgery, Oral education
- Abstract
Introduction: The academic profile of a specialty can be measured in a number of ways. In the selection process for entry into higher training in oral & maxillofacial surgery (OMFS) and for interface fellowships in surgery trainees are awarded points for papers published, presentations, teaching and learning, grants and higher degrees. General information about career development can provide trainers, and trainees, with information and guidance., Methods: A web-based questionnaire was developed and distributed via electronic mailing lists to all OMFS specialist trainees. Basic demographic information was collected. Previous, current and future career plans were questioned, as was academic background in terms of publications, presentations, prizes and research grants as well as further degrees and examinations., Results: One hundred and five OMFS specialty registrar trainees (StR) replied (76.6% response rate). 83.3% were male and the average age of all trainees was 37 years old. 74.7% obtained a training post on the first application. 62.6% of trainees were keen to practice in trauma surgery. 76.6% were keen to undertake a fellowship. 20.9% were keen to be involved in academia (teaching) and 9.9% in academia (research). 22.1% of trainees had obtained grants., Conclusion: Those involved in appointing to training programmes will now be able to see the level of competition. Future applicants to training programmes in oral and maxillofacial surgery in the United Kingdom are now aware of the level of competition. OMFS is not immune to the 'academic crisis' that exists in other surgical specialties, and the completion of higher degrees and entry in to academic careers should be encouraged and supported among trainees with an interest.
- Published
- 2013
- Full Text
- View/download PDF
36. High-throughput mosquito and fly bioassay system for natural and artificial substrates treated with residual insecticides.
- Author
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Aldridge RL, Wynn WW, Britch SC, Allan SA, Walker TW, Geden CJ, Hogsette JA, and Linthicum KJ
- Subjects
- Animals, Female, Male, Culicidae, Insecticides, Pesticide Residues, Toxicity Tests instrumentation
- Abstract
A high-throughput bioassay system to evaluate the efficacy of residual pesticides against mosquitoes and muscid flies with minimal insect handling was developed. The system consisted of 4 components made of readily available materials: 1) a CO2 anaesthetizing chamber, 2) a specialized aspirator, 3) a cylindrical flat-bottomed glass bioassay chamber assembly, and 4) a customized rack.
- Published
- 2013
- Full Text
- View/download PDF
37. West of Ireland facial injury study. Part 2.
- Author
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Walker TW, Donnellan J, Byrne S, McArdle N, Kerin MJ, and McCann PJ
- Subjects
- Age Distribution, Athletic Injuries epidemiology, Facial Injuries etiology, Female, Humans, Ireland epidemiology, Male, Prospective Studies, Sex Distribution, Violence statistics & numerical data, Alcohol Drinking adverse effects, Athletic Injuries classification, Emergency Service, Hospital statistics & numerical data, Facial Injuries epidemiology, Protective Devices statistics & numerical data
- Abstract
The pattern, presentation, and volume of facial injury in the west of Ireland are subjectively different from those in the United Kingdom. We know of no prospective regional study of facial injury in Ireland to date, and nationally there is no system in place to collect data on injury. The epidemiology of facial trauma has important implications for the development of health services, the education and training of clinicians, workforce planning, prevention of injury, and promotion of health. Over 1 week we did a multicentre prospective data collection study involving all emergency departments in the west of Ireland. All patients who attended with facial injuries were included (n=325), and those with injuries solely of the scalp and neck were excluded. The proforma recorded a patient's characteristics, details of injury and presentation, treatment and follow-up. It also included relation with sport, alcohol, assault, and animals. Eighty-two fractures were suspected, of which 46% were nasal. Accidents caused 75% of injuries and sport caused 27%. Fractures were sustained by 63% (n=5) of those wearing helmets while playing hurling, but by only 22% of those who were not. Helmets did, however, reduce the total number of injuries. Injuries were associated with alcohol (23%), assault (14%), falls (38%), and motor vehicle crashes (11%). Because of the differences in aetiology, different avenues and methods are required to prevent injury. Staff in emergency departments will need training in this area, given the large proportion of facial trauma in the region., (Copyright © 2012. Published by Elsevier Ltd.)
- Published
- 2012
- Full Text
- View/download PDF
38. West of Ireland facial injury study. Part 1.
- Author
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Walker TW, Byrne S, Donnellan J, McArdle N, Kerin MJ, and McCann PJ
- Subjects
- Age Distribution, Athletic Injuries epidemiology, Facial Injuries etiology, Female, Humans, Ireland epidemiology, Male, Prospective Studies, Sex Distribution, Violence statistics & numerical data, Alcohol Drinking adverse effects, Emergency Service, Hospital statistics & numerical data, Facial Injuries epidemiology
- Abstract
The pattern, presentation, and volume of facial injury in the west of Ireland are subjectively different from that in the United Kingdom. We know of no prospective regional study of facial injury in Ireland to date, and nationally there is no system in place to collect data on injury. The epidemiology of facial trauma has important implications for the development of health services, the education and training of clinicians, workforce planning, prevention of injury, and promotion of health. Over one week we did a multicentre prospective data collection study involving all emergency departments in the west of Ireland. All patients who attended with facial injuries were included, and those with injuries solely of the scalp and neck were excluded. The proforma recorded patients' characteristics, details of injury and presentation, treatment and follow-up. It also included relation with sport, alcohol, assault, and animals. During the study period 325 patients were injured (5% of attendances at emergency departments in the region). The mean was 29.8%, and 68% were male. Falls caused 39% of injuries, sport 27%, and assault 14%. Sixteen percent of patients were treated in oral and maxillofacial surgery departments, and 16% in plastics, and ear, nose and throat (ENT) departments combined. There were 166 serious injuries. The busiest 24h were from Saturday at 09:00. Forty-five percent presented between 1 and 2h after injury. Different approaches and methods may be needed to prevent injury because of differences in aetiology, and staff in emergency departments will need training in this area, given the large proportion of facial injuries in the region., (Copyright © 2011 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
39. Qualitative comparison of curricula in oral and maxillofacial surgery training. Part 1: dental foundation training.
- Author
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Varley IS, Argiris K, Walker TW, and Magennis P
- Subjects
- Clinical Competence, Education, Dental, Graduate standards, Educational Measurement, Humans, Qualitative Research, Surgery, Oral standards, United Kingdom, Curriculum, Education, Dental, Graduate methods, Surgery, Oral education
- Abstract
Dental foundation training (DFT) is a two-year programme being introduced for new dental graduates. It is not currently compulsory but there are plans to make it so. Those studying oral and maxillofacial surgery (OMFS) must complete both medical and dental degrees, and training, and if DFT becomes a requirement for dental registration, the process could be lengthened. We aimed to examine the overlap between DFT and medical foundation and core surgical training, to highlight areas of potential duplication for those who completed their surgical training before graduating from dental school. Relevant curricula for OMFS trainees were identified and compared with the DFT curriculum, and a qualitative assessment tool was developed to measure overlap between non-analogous curricula. Depending on previous experience, an OMFS trainee who completed core training in surgery before studying dentistry may already have covered 76% of the DFT curriculum. Areas with the least duplication in clinical skills (53%) were notably those related to restorative dentistry, prosthodontics, and periodontology, but there was considerable overlap in non-clinical areas such as communication skills (100%) and professionalism (90%). A method of standardised assessment of previous experience may allow for DFT to be shortened for OMFS trainees., (Copyright © 2011 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
40. Qualitative comparison of curricula in oral and maxillofacial surgery training. Part 2: oral surgery.
- Author
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Walker TW, Varley IS, Argiris K, and Magennis P
- Subjects
- Clinical Competence, Education, Dental, Graduate standards, Humans, Qualitative Research, United Kingdom, Curriculum, Education, Dental, Graduate methods, Surgery, Oral education
- Abstract
A comparison between the curricula for specialist training in oral surgery (OS), and oral and maxillofacial surgery (OMFS) illustrates the overlap between the two specialties. We identified and compared relevant curricula for OMFS with competencies in the OS specialist-training curriculum using a qualitative assessment to establish the degree of overlap. All competencies within the OS curriculum are covered by OMFS curricula, and 21 of 96 OMFS clinical competencies are covered by OS core competencies. The majority of OMFS competencies are unique and are not directly comparable with those in the OS curriculum. Knowledge of this overlap may help to avoid unnecessary duplication in the training of those who wish to transfer specialty., (Copyright © 2011 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
41. Further evaluation of spray characterization of sprayers typically used in vector control.
- Author
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Hoffmann WC, Walker TW, Fritz BK, Farooq M, Smith VL, Robinson CA, and Lan Y
- Subjects
- Animals, Military Personnel, Particle Size, United States, Insecticides chemistry, Mosquito Control instrumentation, Mosquito Control methods
- Abstract
This work reports droplet-size data measured as part of a collaborative testing program between the US Department of Agriculture, Agricultural Research Service, and the US Navy, Navy Entomological Center for Excellence. This is an ongoing relationship that seeks to test new and revised spray technologies that may potentially be used by deployed personnel. As new equipment comes to market or when existing equipment is modified they are all integrated into this annual testing. During the 2011 equipment evaluations, 24 sprayers were operated across their range of available settings (pressure and flow rate), using both water and oil solutions. Droplet-size data as measured with laser diffraction ranged from 4 to 223 microm (volume median diameter). Generally, as the spray rate increased, droplet size increased, and as the pressure increased at a given same spray rate, droplet size decreased. This information allows users to set up and operate these sprayers in a manner such that a particular droplet size is applied optimizing efficiency and efficacy of applications.
- Published
- 2012
- Full Text
- View/download PDF
42. Re: Andrade NN, Raikwar K. Congenital benign teratoma of the tongue with bifid tip, ankyloglossia and polydactyly: report of case.
- Author
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Walker TW, Ayliffe P, and Miedzybrodzka Z
- Subjects
- Humans, Glossectomy methods, Lingual Frenum abnormalities, Polydactyly complications, Teratoma congenital, Tongue Neoplasms congenital
- Published
- 2012
- Full Text
- View/download PDF
43. Oral cavity examination: beyond the core curriculum?
- Author
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Shanks LA, Walker TW, McCann PJ, and Kerin MJ
- Subjects
- Curriculum, Female, Humans, Male, Schools, Medical, Students, Medical, Surveys and Questionnaires, United Kingdom, Diagnosis, Oral education, Education, Medical, Undergraduate, Mouth Neoplasms diagnosis
- Abstract
There has been little improvement in the survival of patients with oral cancer despite advances in treatment, and late presentation of the disease is one reason for this poor outcome. Research and experience tell us that tuition in medical schools about examination of the oral cavity is poor. We aimed to ascertain the opinions and experience of students regarding this in our institution by dissemination of a web-based anonymous questionnaire that focused on education about examination of the oral cavity and experience in carrying it out. From a cohort of 600 students 458 (76%) responded. A total of 334 (73%) had not been taught how to examine the oral cavity, 372 (81%) had had no experience of doing so in patients, and only 13/86 (15%) felt confident to diagnose a carcinoma of the lip or oral cavity. Eighty-nine percent felt that the tuition given had not been adequate. Examination of the oral cavity cannot be considered part of the core clinical curriculum, and medical schools and departments of oral and maxillofacial surgery urgently need to embrace the introduction of the necessary skills., (Copyright © 2011 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
44. Evaluation of ULV applications against Old World sand fly (Diptera: Psychodidae) species in equatorial Kenya.
- Author
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Britch SC, Linthicum KJ, Walker TW, Farooq M, Gordon SW, Clark JW, Ngere F, Ngonga D, and Chepchieng C
- Subjects
- Animals, Kenya, Weather, Insect Control, Insect Vectors, Insecticides administration & dosage, Psychodidae
- Abstract
Reducing populations of phlebotomine sand flies in areas prevalent for human leishmaniases is of ongoing importance to United States military operations and civilian populations in endemic regions. However, not enough is known regarding the efficacy of Department of Defense-approved pesticides and equipment against sand flies; specifically, the potential for ultra-low volume (ULV) pesticide applications to control Old World sand fly vectors. In this study we examine two sprayers, the Terminator ULV and the Grizzly ULV, with UV-labeled Duet and Fyfanon in four combinations against caged Phlebotomus duboscqi (Neveu-Lemaire) and wild sand fly populations in a natural environment in western Kenya. All equipment and Fyfanon have United States military National Stock Numbers and both pesticides are registered with the United States Environmental Protection Agency. Caged sand flies were reared from local P. duboscqi and the area has long been studied because of high incidences of human cutaneous and visceral Leishmania. Patterns of mortality across grids of caged sand flies showed greater efficacy from the Grizzly ULV regardless of chemical. The Terminator ULV performed well with Duet but with a less uniform and overall lower rate of mortality across the spray grid. Sampling of wild populations before and after treatments suggested local population suppression from ULV treatments, as well as a possible repellent effect in nearby untreated areas. Surprisingly, ULV active ingredient deposition inferred from patterns of UV-labeled droplets captured on cotton ribbons adjacent to sand fly cages in spray plots did not match patterns of mortality. We discuss the implications of this study, the first of its kind, for future military preventive medicine activities, including relative performance costs and benefits of larger or smaller sprayers, and the relative stability of ULV-induced mortality patterns in varied or sub-optimal conditions.
- Published
- 2011
- Full Text
- View/download PDF
45. Insertion mechanism of a poly(ethylene oxide)-poly(butylene oxide) block copolymer into a DPPC monolayer.
- Author
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Leiske DL, Meckes B, Miller CE, Wu C, Walker TW, Lin B, Meron M, Ketelson HA, Toney MF, and Fuller GG
- Subjects
- Microscopy, Fluorescence, Rheology, Surface Properties, X-Ray Diffraction, 1,2-Dipalmitoylphosphatidylcholine chemistry, Epoxy Compounds chemistry, Polyethylene Glycols chemistry
- Abstract
Interactions between amphiphilic block copolymers and lipids are of medical interest for applications such as drug delivery and the restoration of damaged cell membranes. A series of monodisperse poly(ethylene oxide)-poly(butylene oxide) (EOBO) block copolymers were obtained with two ratios of hydrophilic/hydrophobic block lengths. We have explored the surface activity of EOBO at a clean interface and under 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayers as a simple cell membrane model. At the same subphase concentration, EOBO achieved higher equilibrium surface pressures under DPPC compared to a bare interface, and the surface activity was improved with longer poly(butylene oxide) blocks. Further investigation of the DPPC/EOBO monolayers showed that combined films exhibited similar surface rheology compared to pure DPPC at the same surface pressures. DPPC/EOBO phase separation was observed in fluorescently doped monolayers, and within the liquid-expanded liquid-condensed coexistence region for DPPC, EOBO did not drastically alter the liquid-condensed domain shapes. Grazing incidence X-ray diffraction (GIXD) and X-ray reflectivity (XRR) quantitatively confirmed that the lattice spacings and tilt of DPPC in lipid-rich regions of the monolayer were nearly equivalent to those of a pure DPPC monolayer at the same surface pressures., (© 2011 American Chemical Society)
- Published
- 2011
- Full Text
- View/download PDF
46. Longevity and efficacy of bifenthrin treatment on desert-pattern US military camouflage netting against mosquitoes in a hot-arid environment.
- Author
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Britch SC, Linthicum KJ, Wynn WW, Aldridge RL, Walker TW, Farooq M, Dunford JC, Smith VL, Robinson CA, Lothrop BB, Snelling M, Gutierrez A, Wittie J, and White G
- Subjects
- Animals, Arthropod Vectors, Desert Climate, Military Facilities, United States, Mosquito Control instrumentation, Mosquito Nets, Pesticide Residues analysis, Pyrethrins analysis
- Abstract
The current Department of Defense pest management system does not provide adequate protection from arthropod disease vectors to personnel deployed in support of US military operations. We hypothesized that military camouflage netting, ubiquitous around living and working areas in current US military operations in Africa and the Middle East, treated with a residual pesticide such as bifenthrin may reduce the presence of biting insects and improve the military pest management system. In this study, we examined the longevity and efficacy of bifenthrin applied to camouflage netting material at the maximum label rate of 0.03 liter formulation (7.9% AI) per 92.9 m2 against field populations of mosquitoes in southern California in a hot-arid environment similar to regions of Iraq, Afghanistan, and the Horn of Africa. We showed that bifenthrin treatment of camouflage netting was effective at reducing mosquito populations, predominantly Psorophora columbiae and Aedes vexans, by an average of up to 46% for 56 days, and could cause as much as 40% mortality in Culex quinquefasciatus in laboratory bioassays for nearly 2 months postapplication. These population reductions could translate to commensurate reductions in risk of exposure to mosquito-borne pathogens, and could potentially be effective against sand flies and filth flies.
- Published
- 2011
- Full Text
- View/download PDF
47. The emergence of spanking among a representative sample of children under 2 years of age in north Carolina.
- Author
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Zolotor AJ, Robinson TW, Runyan DK, Barr RG, and Murphy RA
- Abstract
Spanking is common in the United States but less common in many European countries in which it has been outlawed. Being spanked has been associated with child abuse victimization, poor self-esteem, impaired parent-child relationships, and child and adult mental health, substance abuse, and behavioral consequences. Being spanked as a child has also been shown to increase the likelihood of abusing one's own children or spouse as an adult. Spanking of very young children less than two is almost never recommended even among experts that consider spanking as reasonable in some circumstances. Using a cross-sectional anonymous telephone survey, we describe spanking rates among a representative sample of North Carolina mothers of children less than 2 years old and the association of spanking with demographic characteristics. A substantial proportion of mothers admit to spanking their very young children. The rate of spanking in the last year among all maternal respondents was 30%. Over 5% of the mothers of 3-month olds reported spanking. Over 70% of the mothers of 23-month olds reported spanking. Increased spanking was associated with higher age of the child and lower maternal age. With every month of age, a child had 27% increased odds of being spanked. Early spanking has been shown to be associated with poor cognitive development in early childhood. Further, early trauma has been shown to have significant effects on the early developing brain. It is therefore critical that health and human services professionals address the risk of corporal punishment as a method of discipline early in the life of the child. The spanking of very young children may be an appropriate locus for policy and legislative debates regarding corporal punishment.
- Published
- 2011
- Full Text
- View/download PDF
48. Curriculum crutch.
- Author
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Walker TW
- Subjects
- Education, Dental methods, Humans, Mass Media, Curriculum, Education, Dental standards, Learning
- Published
- 2011
- Full Text
- View/download PDF
49. Electronic follow-up of facial lacerations in the emergency department.
- Author
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Walker TW, O'Connor N, Byrne S, McCann PJ, and Kerin MJ
- Subjects
- Adolescent, Adult, Aged, Cell Phone, Child, Child, Preschool, Cicatrix, Electronic Mail, Emergency Service, Hospital, Feasibility Studies, Female, Humans, Internet, Male, Middle Aged, Patient Satisfaction, Photography, Sutures, Young Adult, Facial Injuries therapy, Lacerations therapy, Patient Compliance statistics & numerical data, Remote Consultation statistics & numerical data, Wound Healing
- Abstract
It is often difficult for emergency department staff to follow up the primary closure of simple facial lacerations. This is important to allow closure of the feedback loop. Consecutive patients who were sutured by a single operator using the same technique were asked to send a photograph of the laceration six months and 12 months afterwards. The patients had Internet access and a digital camera, or a mobile phone with a camera. They were given a leaflet with the details of the email address or mobile number to send the picture to. A reminder telephone call was made to each patient at six months and 12 months, and the email address or mobile number to send the picture to was given again. In each telephone call patients were asked to grade the healing on a 5-point scale from 1 = very happy to 5 = very unhappy. At 13 months all patients were re-contacted and reminded again. Fifty patients were included in the study (33 males). The cause of injury was sport in 17 patients, assault in 18 and accidents in 15. At six months, 23 patients stated that they were happy and 27 were very happy with the scar. The mean score was 1.5. At 12 and 13 months, four patients were happy and 46 very happy. The mean score was 1.1. Twenty-four patients said they would use a computer/camera to send in the follow-up image, and 26 patients had a mobile phone with a camera and said they would use that. Despite the reminders, no patients sent a photograph. The results provide no evidence to support the use of photographs sent by email or text message for the follow-up of facial lacerations sutured in the emergency department.
- Published
- 2011
- Full Text
- View/download PDF
50. Impact of electrostatic and conventional sprayers characteristics on dispersion of barrier spray.
- Author
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Farooq M, Walker TW, Heintschel BP, Hoffmann WC, Fritz BK, Smith VL, Robinson CA, and English T
- Subjects
- Animals, Mosquito Control methods, Static Electricity, Aerosols administration & dosage, Insecticides chemistry, Mosquito Control instrumentation
- Abstract
A study was conducted to analyze the performance of 3 electrostatic (Electrolon BP-2.5, Spectrum Electrostatic 4010, and Spectrum Electrostatic head on a Stihl 420) and 2 conventional (Buffalo Turbine CSM2 and Stihl 420) sprayers for barrier sprays to suppress an adult mosquito population in an enclosed area. Sprayer characteristics such as charge-mass ratio, air velocity, flow rate, and droplet spectra were measured while spraying water. Dispersion of the spray cloud from these sprayers was determined using coverage on water-sensitive cards at various heights (0.5 m, 1.0 m, 1.5 m, 2.0 m, 2.5 m, and 3.0 m) and depths (1 m, 3 m, and 5 m) into the under-forest vegetation while spraying bifenthrin (Talstar 7.9% AI; FMC Corporation, Philadelphia, PA) at the rate of 21.8 ml/300 m of treated row. The charge-mass ratio data show that Electrostatic head on a Stihl 420 did not impart enough charge to the droplets to be considered as an electrostatic sprayer. In general, the charged spray cloud moved down toward the ground. The Electrolon BP 2.5 had significantly lower spray coverage on cards, indicating lack of spray dispersion. This sprayer had the lowest air velocity and did not have the air capacity needed to deliver droplets close to the target for electrostatic force to affect deposition. The analysis shows that these 2 sprayers are not a suitable choice for barrier sprays on vegetation. The results indicate that the Buffalo Turbine is suitable for barriers wider than 3 m, and the Spectrum 4010 and Stihl 420 are suitable for 1-3-m-wide barriers.
- Published
- 2010
- Full Text
- View/download PDF
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