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Yabsley MJ, Garrett KB, Thompson AT, Box EK, Giner MR, Haynes E, Barron H, Schneider RM, Coker SM, Beasley JC, Borchert EJ, Tumlison R, Surf A, Dukes CG, Olfenbuttel C, Brown JD, Swanepoel L, Cleveland CA. Otterly diverse - A high diversity of Dracunculus species (Spirurida: Dracunculoidea) in North American river otters ( Lontra canadensis). Int J Parasitol Parasites Wildl 2024; 23:100922. [PMID: 38516639 PMCID: PMC10955650 DOI: 10.1016/j.ijppaw.2024.100922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/01/2024] [Accepted: 03/02/2024] [Indexed: 03/23/2024]
Abstract
The genus Dracunculus contains numerous species of subcutaneous parasites of mammals and reptiles. In North America, there are at least three mammal-infecting species of Dracunculus. Reports of Dracunculus infections have been reported from river otters (Lontra canadensis) since the early 1900s; however, little is known about the species infecting otters or their ecology. Most reports of Dracunculus do not have a definitive species identified because females, the most common sex found due to their larger size and location in the extremities of the host, lack distinguishing morphological characteristics, and few studies have used molecular methods to confirm identifications. Thus, outside of Ontario, Canada, where both D. insignis and D. lutrae have been confirmed in otters, the species of Dracunculus in river otters is unknown. In the current study, molecular characterization of nematodes from river otters revealed a high diversity of Dracunculus species. In addition to confirming D. insignis infections, two new clades were detected. One clade was a novel species in any host and the other was a clade previously detected in Virginia opossums (Didelphis virginiana) from the USA and a domestic dog from Spain. No infections with D. lutrae were detected and neither new lineage was genetically similar to D. jaguape, which was recently described from a neotropical otter (Lontra longicaudis) from Argentina. These data also indicate that Dracunculus spp. infections in otters are widespread throughout Eastern North America. Currently the life cycles for most of the Dracunculus spp. infecting otters are unknown. Studies on the diversity, life cycle, and natural history of Dracunculidae parasites in wildlife are important because the related parasite, D. medinensis (human Guinea worm) is the subject of an international eradication campaign and there are increasing reports of these parasites in new geographic locations and new hosts, including new species in humans and domestic dogs.
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Affiliation(s)
- Michael J. Yabsley
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
- Center for Ecology of Infectious Diseases, Athens, GA, 30602, USA
| | - Kayla B. Garrett
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - Alec T. Thompson
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
- Center for Ecology of Infectious Diseases, Athens, GA, 30602, USA
| | - Erin K. Box
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
| | - Madeline R. Giner
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
| | - Ellen Haynes
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
| | - Heather Barron
- Clinic for the Rehabilitation of Wildlife, Sanibel, FL, 33957, USA
| | | | - Sarah M. Coker
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
| | - James C. Beasley
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA
| | - Ernest J. Borchert
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA
| | - Renn Tumlison
- Applied Science and Technology, Henderson State University, Arkadelphia, AR, 71999, USA
| | - Allison Surf
- Applied Science and Technology, Henderson State University, Arkadelphia, AR, 71999, USA
| | - Casey G. Dukes
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
- North Carolina Wildlife Resources Commission, NCSU Centennial Campus, 1751 Varsity Drive, Raleigh, NC, 27606, USA
| | - Colleen Olfenbuttel
- North Carolina Wildlife Resources Commission, NCSU Centennial Campus, 1751 Varsity Drive, Raleigh, NC, 27606, USA
| | - Justin D. Brown
- Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA, 16802, USA
| | - Liandrie Swanepoel
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
| | - Christopher A. Cleveland
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
- Center for Ecology of Infectious Diseases, Athens, GA, 30602, USA
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Troiano AT, Peel M, Cameron AI, Bast R, Flewelling L, Abbott J, Barron H. INVESTIGATING BLOOD LACTATE CONCENTRATION AS A PROGNOSTIC INDICATOR FOR BIRDS PRESENTING WITH BREVETOXICOSIS: 2020-2021. J Zoo Wildl Med 2023; 54:23-31. [PMID: 36971625 DOI: 10.1638/2022-0087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2022] [Indexed: 03/29/2023] Open
Abstract
Large blooms of the dinoflagellate Karenia brevis cause annual harmful algal bloom events, or "red tides" on Florida's Gulf Coast. Each year, the Clinic for the Rehabilitation of Wildlife (CROW) is presented with hundreds of cases of aquatic birds that exhibit neurologic clinical signs due to brevetoxicosis. Double-crested cormorants (Phalacrocorax auratus) are the most common species seen, and typically present with a combination of ataxia, head tremors, knuckling, and/or lagophthalmos. Blood lactate levels are known to increase in mammals for a variety of reasons, including stress, hypoxia, sepsis, and trauma, but there is limited literature on blood lactate values in avian species. The objective of this study was to determine the prognostic value of blood lactate concentration on successful rehabilitation and release of birds presenting with clinical signs consistent with brevetoxicosis. Blood lactate levels were collected on intake, the morning after presentation and initial therapy, and prior to disposition (release or euthanasia) from 194 birds (including 98 cormorants) representing 17 species during the 2020-2021 red tide season. Overall, mean blood lactate at intake, the morning after intake, and predisposition was 2.9, 2.8, and 3.2 mmol/L, respectively, for released birds across all species (2.9, 2.9, and 3.2 mmol/L for released cormorants); 3.4, 3.4, and 6.5 mmol/L for birds that died (4.0, 3.5, and 7.9 mmol/L for cormorants that died); and 3.1, 3.5, and 4.7 mmol/L for birds that were euthanized (3.5, 4.7, and 4.9 mmol/L for cormorants that were euthanized). On average, birds that died or were euthanized had an elevated lactate at all time points as compared to those that were released, but these results were not statistically significant (P = 0.13). These results indicate that blood lactate levels do not appear to be useful as a prognostic indicator for successful release of birds, including double-crested cormorants, affected by brevetoxicosis.
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Affiliation(s)
| | - Melanie Peel
- Clinic for the Rehabilitation of Wildlife, Sanibel, FL 33957 USA
| | | | - Robin Bast
- Clinic for the Rehabilitation of Wildlife, Sanibel, FL 33957 USA
| | - Leanne Flewelling
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, St. Petersburg, FL 33701, USA
| | - Jay Abbott
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, St. Petersburg, FL 33701, USA
| | - Heather Barron
- Clinic for the Rehabilitation of Wildlife, Sanibel, FL 33957 USA
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Garrett KB, Hernandez SM, Balsamo G, Barron H, Beasley JC, Brown JD, Cloherty E, Farid H, Gabriel M, Groves B, Hamer S, Hill J, Lewis M, McManners K, Nemeth N, Oesterle P, Ortiz S, Peshock L, Schnellbacher R, Schott R, Straif-Bourgeois S, Yabsley MJ. Prevalence, distribution, and diversity of cryptic piroplasm infections in raccoons from selected areas of the United States and Canada. Int J Parasitol Parasites Wildl 2019; 9:224-233. [PMID: 31198681 PMCID: PMC6555877 DOI: 10.1016/j.ijppaw.2019.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/24/2019] [Accepted: 05/25/2019] [Indexed: 12/12/2022]
Abstract
The order Piroplasmida contains a diverse group of intracellular parasites, many of which can cause significant disease in humans, domestic animals, and wildlife. Two piroplasm species have been reported from raccoons (Procyon lotor), Babesia lotori (Babesia sensu stricto clade) and a species related to Babesia microti (called B. microti-like sp.). The goal of this study was to investigate prevalence, distribution, and diversity of Babesia in raccoons. We tested raccoons from selected regions in the United States and Canada for the presence of Babesia sensu stricto and Babesia microti-like sp. piroplasms. Infections of Babesia microti-like sp. were found in nearly all locations sampled, often with high prevalence, while Babesia sensu stricto infections had higher prevalence in the Southeastern United States (20–45% prevalence). Co-infections with both Babesia sp. were common. Sequencing of the partial 18S rRNA and cytochrome oxidase subunit 1 (cox1) genes led to the discovery of two new Babesia species, both found in several locations in the eastern and western United States. One novel Babesia sensu stricto sp. was most similar to Babesia gibsoni while the other Babesia species was present in the ‘western piroplasm’ group and was related to Babesia conradae. Phylogenetic analysis of the cox1 sequences indicated possible eastern and western genetic variants for the three Babesia sensu stricto species. Additional analyses are needed to characterize these novel species; however, this study indicates there are now at least four species of piroplasms infecting raccoons in the United States and Canada (Babesia microti-like sp., Babesia lotori, a novel Babesia sensu stricto sp., a novel western Babesia sp.) and a possible fifth species (Babesia sensu stricto) in raccoons in Japan. Raccoons in all locations tested were infected with piroplasms. Babesia microti-like sp. was commonly found in raccoons throughout North America. Babesia sensu stricto spp. were less common throughout North America. Four, possibly five, distinct species of piroplasms in raccoons. Possible spatial genetic variation within the two raccoon piroplasm species.
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Affiliation(s)
- Kayla B. Garrett
- Warnell School of Forestry and Natural Resources, 140 Green Street, University of Georgia, Athens, GA, 30602, USA
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, 589 DW Brooks Drive, University of Georgia, Athens, GA, 30602, USA
- Corresponding author. 589 D. W. Brooks Drive, Wildlife Health Building, Athens, GA, 30602, USA.
| | - Sonia M. Hernandez
- Warnell School of Forestry and Natural Resources, 140 Green Street, University of Georgia, Athens, GA, 30602, USA
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, 589 DW Brooks Drive, University of Georgia, Athens, GA, 30602, USA
| | - Gary Balsamo
- Louisiana Department of Health, 628 N. 4th Street, Baton Rouge, LA, 70802, USA
| | - Heather Barron
- Clinic for the Rehabilitation of Wildlife (CROW), 3883 Sanibel Captiva Road, Sanibel Island, FL, 33957, USA
| | - James C. Beasley
- Warnell School of Forestry and Natural Resources, 140 Green Street, University of Georgia, Athens, GA, 30602, USA
- Savannah River Ecology Laboratory, University of Georgia, P.O. Drawer E., Aiken, SC, 29802, USA
| | - Justin D. Brown
- Pennsylvania Game Commission, 2001 Elmerton Ave, Harrisburg, PA, 17110, USA
| | - Erin Cloherty
- New Orleans Mosquito, Termite, and Rodent Control Board, 2100 Leon C Simon Dr., New Orleans, LA, 70122, USA
| | - Hossain Farid
- Department of Animal Science and Aquaculture, Faculty of Agriculture, Agricultural Campus, PO Box 550, Dalhousie University, Truro, Nova Scotia, B2N 5E3, Canada
| | - Mourad Gabriel
- Karen C. Drayer Wildlife Health Center, University of California Davis School of Veterinary Medicine, Davis, CA, 95616, USA
- Integral Ecology Research Center, 239 Railroad Ave, Blue Lake, CA, 95525, USA
| | | | - Sarah Hamer
- Department of Veterinary Integrative Biosciences, TAMU 4458, Texas A&M University, College Station, TX, 77843, USA
| | - Julia Hill
- Clinic for the Rehabilitation of Wildlife (CROW), 3883 Sanibel Captiva Road, Sanibel Island, FL, 33957, USA
| | - Meghan Lewis
- Warnell School of Forestry and Natural Resources, 140 Green Street, University of Georgia, Athens, GA, 30602, USA
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, 589 DW Brooks Drive, University of Georgia, Athens, GA, 30602, USA
- Young Scholars Program at the University of Georgia, Athens, GA, 30602, USA
| | - Katie McManners
- Warnell School of Forestry and Natural Resources, 140 Green Street, University of Georgia, Athens, GA, 30602, USA
| | - Nicole Nemeth
- Warnell School of Forestry and Natural Resources, 140 Green Street, University of Georgia, Athens, GA, 30602, USA
- Ontario Veterinary College, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
| | - Paul Oesterle
- Ontario Veterinary College, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
| | - Sebastian Ortiz
- Warnell School of Forestry and Natural Resources, 140 Green Street, University of Georgia, Athens, GA, 30602, USA
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, 589 DW Brooks Drive, University of Georgia, Athens, GA, 30602, USA
| | - Lea Peshock
- Greenwood Wildlife Rehabilitation Center, 5761 Ute Hwy, Longmont, CO, 80503, USA
| | | | - Renee Schott
- Wildlife Rehabilitation Center of Minnesota, 2530 Dale St N, Roseville, MN, 55113, USA
| | - Susanne Straif-Bourgeois
- Louisiana State University Health Sciences Center, School of Public Health, 2020 Gravier Street, New Orleans, LA, 70112, USA
| | - Michael J. Yabsley
- Warnell School of Forestry and Natural Resources, 140 Green Street, University of Georgia, Athens, GA, 30602, USA
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, 589 DW Brooks Drive, University of Georgia, Athens, GA, 30602, USA
- Corresponding author. 589 D. W. Brooks Drive, Wildlife Health Building, Athens, GA, 30602, USA.
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Barron H, Bennett A, Carpenter JW, Hoefer H, Paul-Murphy J, Tully TN, Rich G. The veterinary bucket list: what's left to do? J Avian Med Surg 2014; 28:64-7. [PMID: 24881156 DOI: 10.1647/1082-6742-28.1.64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Deepak FL, Casillas-Garcia G, Esparza R, Barron H, Jose-Yacaman M. New Insights into the structure of Pd-Au nanoparticles as revealed by aberration-corrected STEM. J Cryst Growth 2011; 325:60-67. [PMID: 21804646 PMCID: PMC3144588 DOI: 10.1016/j.jcrysgro.2011.04.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Bimetallic nanoparticles of Au-Pd find important applications in catalysis. Their catalytic performance is directly related to the structure, alloy formation and variation of composition in the structure. A standard idea is that bimetallic nanoparticles can be either an alloy or a core shell structure. Our group has investigated the structure and composition of Pd-Au nanoparticles by using aberration corrected high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). We reported previously that the nanoparticles are composed of an evenly alloyed inner core, an Au-rich intermediate layer, and a Pd-rich outer shell. The structure is more complicated than what simple models can predict. In this paper we report additional studies of this system wherein by carrying out spectral and chemical analysis (STEM*-EDAX, STEM-EELS) the interface structure can now be better identified and understood. Apart from the three-layered core-shell structures we have also been able to observe in some cases a four-layered core-shell structure as well. The entire core-shell structure is not rigid and there is indeed intercalation of Au-Pd into the other layers as well. In addition we have been able to locate stacking faults present in the nanoparticles. We also address the problem of the interface structure between the layers. By using nanodiffraction we have found that the whole structure of the nanoparticles becomes hcp in contrast to the bulk structure of Au or Pd.
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Affiliation(s)
- Francis Leonard Deepak
- Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, USA
- International Iberian Nanotechnology Laboratory, Avda Mestre Jose Veiga, Braga 4715, Portugal
| | - Gilberto Casillas-Garcia
- Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, USA
| | - Rodrigo Esparza
- Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, USA
| | - H. Barron
- Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, USA
| | - Miguel Jose-Yacaman
- Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, USA
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Miller MK, Lee JH, Blanc PD, Pasta DJ, Gujrathi S, Barron H, Wenzel SE, Weiss ST. TENOR risk score predicts healthcare in adults with severe or difficult-to-treat asthma. Eur Respir J 2006; 28:1145-55. [PMID: 16870656 DOI: 10.1183/09031936.06.00145105] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The aim of the present study was to predict which patients with severe or difficult-to-treat asthma are at highest risk for healthcare utilisation can be predicted so as to optimise clinical management. Data were derived from 2,821 adults with asthma enrolled in The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study. Multiple potential predictors were assessed at baseline using a systematic algorithm employing stepwise logistic regression. Outcomes were asthma-related hospitalisations or emergency department (ED) visits within 6 months following baseline. Overall, 239 subjects (8.5%) reported hospitalisation or ED visits at follow-up. Predictors retained after multivariate analysis were as follows: younger age; female sex; non-white race; body mass index > or =35 kg x m(-2); post-bronchodilator per cent predicted forced vital capacity <70%; history of pneumonia; diabetes; cataracts; intubation for asthma; and three or more steroid bursts in the prior 3 months. A final risk score derived from the logistic regression model ranged from 0-18 and was highly predictive (c-index: 0.78) of hospitalisation or ED visits. This tool was re-tested in a prospective validation using outcomes at 12- to 18-months follow-up among the same cohort (c-index: 0.77). The risk score derived is a clinically useful tool for assessing the likelihood of asthma-related hospitalisation or emergency department visits in adults with severe and difficult-to-treat asthma.
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Affiliation(s)
- M K Miller
- Genentech, Inc, 1 DNA Way, MS 214B, South San Francisco, CA 94044, USA.
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Barron H. Use of Helicopter Transportation in Acute Myocardial Infarction in the United States. J Am Coll Cardiol 1998. [DOI: 10.1016/s0735-1097(97)84879-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Arjunan K, Daniels SR, Meyer RA, Schwartz DC, Barron H, Kaplan S. Coronary artery caliber in normal children and patients with Kawasaki disease but without aneurysms: an echocardiographic and angiographic study. J Am Coll Cardiol 1986; 8:1119-24. [PMID: 3760385 DOI: 10.1016/s0735-1097(86)80390-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A total of 110 children aged 3 months to 16 years underwent two-dimensional echocardiography of the coronary arteries. Forty-two normal subjects and 68 patients with Kawasaki disease were evaluated. All 68 patients with Kawasaki disease underwent selective coronary arteriography. The objectives of this study were to 1) develop a normal profile of the proximal left and right coronary arteries as to caliber and shape in infants, toddlers and children using echocardiography; 2) compare the dimensions and shape of the coronary arteries of patients with Kawasaki disease but no obvious aneurysms with those of the coronary arteries of normal children; and 3) develop criteria that would permit distinguishing a large but normal coronary artery from a true aneurysm in patients with Kawasaki disease. In the normal subjects and patients with Kawasaki disease, the caliber of the coronary arteries showed little variability from the ostium to 10 mm distally, and ranged in size from 2 mm in infants to 5 mm in teenagers. There was no significant difference between male and female subjects. The feature that distinguished the large but normal coronary artery without aneurysm from that with an aneurysm was its uniformity of caliber. Also, the caliber of the opposite coronary artery was generally at the lower limits of normal. It appears that the proximal coronary arteries of infants and children can be accurately assessed using high resolution two-dimensional echocardiography, and that sequential evaluation of subtle changes over time may be performed.
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Barron H. Adsorptive Properties of Carbon Black. A New Angle. Rubber Chemistry and Technology 1935. [DOI: 10.5254/1.3548293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Abstract
(1) A new method has been developed for quantitatively determining the adsorptive properties of finely divided fillers, whereby advantage is taken of the partition coefficient of solutes between immiscible solvents. If carbon black is shaken with a mixture of polar and non-polar solvents (e. g., benzene and water) the carbon black is always retained in the non-polar layer after separation. The behavior with other fillers has been investigated. This phenomenon has made it possible rapidly to determine the amount of iodine, benzoic acid, or phenol adsorbed by carbon black from the two phase liquid system by titration of the aqueous layer after equilibrium has been reached. A knowledge of the partition coefficient then enables the adsorption from the non-polar liquid to be readily calculated. (2) The adsorption isotherms for carbon black, degassed carbon black and heat-treated carbon black have been investigated, employing this technic. (3) Since the partition coefficient of a solute between immiscible liquids is unaffected by the presence in either liquid of a substance insoluble in the other phase, the method developed can be used to investigate the effect of dispersed rubber, sulfur, etc., upon the adsorptive properties of the filler. Sulfur and stearic acid were found to have a negligible effect upon the absorptive power of carbon black for phenol benzoic acid, and iodine; whereas the presence of 1 per cent rubber in the benzene phase greatly reduced the ability of carbon black to adsorb the first two of these substances. This action of rubber in depressing adsorption also occurred in the presence of sulfur and stearic acid, and suggests powerful adsorption of rubber upon the surface of carbon black.
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Barron H, Cotton FH. Hysteresis and Reinforcement. Rubber Chemistry and Technology 1932. [DOI: 10.5254/1.3539360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Abstract
1. The relationships between work of extension, work of retraction, and hysteresis loss in vulcanized rubbers loaded with fillers have been examined. 2. The hysteresis loss in vulcanized rubber during a cycle of extension and retraction increases with amplitude to an extent comparable with the increase in work of extension. 3. If the work required to extend a vulcanized rubber to a given elongation be increased by compounding with fillers, the energy lost through hysteresis on slow retraction increases to a comparable extent. Hence reinforcement does not appreciably increase the ability of rubber to store energy. 4. With any rubber vulcanized to optimum tensile properties, hysteresis loss and work of retraction from any elongation are proportional to the work required to extend to that elongation. Therefore if the hysteresis loss during a given cycle be known, the work of retraction from the breaking point can be calculated. 5. The work of retraction from the ultimate breaking point of a vulcanized rubber increases slightly with reinforcement, and becomes greatest when reinforcement is at a maximum. This is thought to be a function of the rubber-filler interface. 6. No filler was found to lessen the work of retraction from the breaking point until the rubber was highly compounded. 7. It is suggested that the increased work required to rupture rubber that has been reinforced with fillers is mainly dissipated in overcoming consequent increased internal friction; a small quantity being converted to potential energy through strain of the filler-rubber interface.
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Affiliation(s)
- H. Barron
- 1Department of Chemistry and Rubber Technology, Northern Polytechnic, London
| | - F. H. Cotton
- 1Department of Chemistry and Rubber Technology, Northern Polytechnic, London
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