Mechanical testing of a steel-reinforced epoxy resin bar and clamp for external skeletal fixation of long-bone fractures in cats     

BJ Leitch  AJ Worth 《New Zealand veterinary journal》2018,66(3):144-153

AIMS: To provide veterinarians with confidence when using a commercially available epoxy resin in external skeletal fixators (ESF), testing was conducted to determine exothermia during curing of the epoxy resin compared to polymethylmethacrylate (PMMA), the hardness of the epoxy resin as a bar over 16 weeks, and the strength of the epoxy resin bar compared with metal clamps in similarly constructed Type 1a ESF constructs simulating the repair of feline long bone fractures.

METHODS: Exothermia of the epoxy resin during curing was tested against PMMA with surface temperatures recorded over the first 15 minutes of curing, using four samples of each product. The hardness of 90 identical epoxy resin bars was tested by subjecting them to cyclic loads (1,000 cycles of 20.5?N, every 7 days) over a 16-week period and impact testing 10 bars every 2 weeks. Ten bars that were not subjected to cyclic loads were impact tested at 0 weeks and another 10 at 16 weeks. Strength of the epoxy resin product, as a bar and clamp composite, was tested against metal SK and Kirschner-Ehmer (KE) clamps and bars in Type 1a, tied-in intramedullary pin, ESF constructs with either 90° or 75° pin placement, subjected to compressive and bending loads to 75?N.

RESULTS: The maximum temperature during curing of the epoxy resin (min 39.8, max 43.0)°C was less than the PMMA (min 85.2, max 98.5)°C (p<0.001). There was no change in hardness of the epoxy resin bars over the 16 weeks of cyclic loading (p=0.58). There were no differences between the median strength of the epoxy resin, SK or KE ESF constructs in compression or bending when tested to 75?N (p>0.05). Stiffness of constructs with 75° pin placement was greater for SK than epoxy resin constructs in compression (p=0.046), and was greater for KE than epoxy resin constructs in bending (p=0.033).

CONCLUSIONS: The epoxy resin tested was found to be less exothermic than PMMA; bars made from the epoxy resin showed durability over an expected fracture healing timeframe and had mechanical strength characteristics comparable to metal bar and clamp ESF constructs.

CLINICAL RELEVANCE: The epoxy resin ESF construct tested in this study can be considered a suitable replacement for SK or KE ESF constructs in the treatment of feline long-bone fractures, in terms of mechanical strength.  相似文献   

Clinical and epidemiological features of West Nile virus equine encephalitis in New South Wales,Australia, 2011     

AJ Read  DS Finlaison  X Gu  PM Hick  BJ Moloney  T Wright  PD Kirkland 《Australian veterinary journal》2019,97(5):133-143

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Ancient diets, ecology, and extinction of 5-million-year-Old horses from florida     

BJ MacFadden  N Solounias  TE Cerling 《Science (New York, N.Y.)》1999,283(5403):824-827

Six sympatric species of 5-million-year-old (late Hemphillian) horses from Florida existed during a time of major global change and extinction in terrestrial ecosystems. Traditionally, these horses were interpreted to have fed on abrasive grasses because of their high-crowned teeth. However, carbon isotopic and tooth microwear data indicate that these horses were not all C4 grazers but also included mixed feeders and C3 browsers. The late Hemphillian Florida sister species of the modern genus Equus was principally a browser, unlike the grazing diet of modern equids. Late Hemphillian horse extinctions in Florida involved two grazing and one browsing species.  相似文献   

Formation of molecular chlorine from the photolysis of ozone and aqueous sea-salt particles     

KW Oum  MJ Lakin  DO DeHaan  T Brauers  BJ Finlayson-Pitts 《Science (New York, N.Y.)》1998,279(5347):74-77

Halogen atoms from the reactions of sea-salt particles may play a significant role in the marine boundary layer. Reactions of sodium chloride, the major component of sea-salt particles, with nitrogen oxides generate chlorine atom precursors. However, recent studies suggest there is an additional source of chlorine in the marine troposphere. This study shows that molecular chlorine is generated from the photolysis of ozone in the presence of sea-salt particles above their deliquescence point; this process may also occur in the ocean surface layer. Given the global distribution of ozone, this process may provide a global source of chlorine.  相似文献   

Elevation change of the southern greenland ice sheet     

CH Davis  CA Kluever  BJ Haines 《Science (New York, N.Y.)》1998,279(5359):2086-2088

Seasat and Geosat satellite altimeter measurements for the Greenland ice sheet (south of 72 degreesN latitude) show that surface elevations above 2000 meters increased at an average rate of only 1. 5 +/- 0.5 centimeters per year from 1978 to 1988. In contrast, elevation changes varied regionally from -15 to +18 centimeters per year, seasonally by +/-15 centimeters, and interannually by +/-8 centimeters. The average growth rate is too small to determine if the Greenland ice sheet is undergoing a long-term change due to a warmer polar climate.  相似文献   

Dissimilar effects of human and elephant disturbance on woodland structure and functional bird diversity in the mopane woodlands of Zambia     

Tripathi  Hemant G.  Mzumara  Tiwonge I.  Martin  Rowan O.  Parr  Catherine L.  Phiri  Chaona  Ryan  Casey M. 《Landscape Ecology》2019,34(2):357-371

Landscape Ecology - Humans and elephants are major disturbance agents in the African savanna woodlands. While both species remove trees, humans selectively harvest larger stems, which are less...  相似文献   

Farmer perception of fall armyworm (Spodoptera frugiderda J.E. Smith) and farm‐level management practices in Zambia     

Monica K Kansiime  Idah Mugambi  Ivan Rwomushana  Winnie Nunda  Julien Lamontagne‐Godwin  Harrison Rware  Noah A Phiri  Gilson Chipabika  Mathias Ndlovu  Roger Day 《Pest management science》2019,75(10):2840-2850

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An in situ single-pass perfusion model for assessing absorption across the intestinal mucosa of the brushtail possum     

BJ McLeod  H Zhang  L Huang  EG Thompson  AG Butt  IG Tucker 《New Zealand veterinary journal》2013,61(4):234-241

AIM: To develop an in situ animal model for assessing absorption of molecules across the intestinal mucosa of possums.

METHODS: A surgical preparation was used to perfuse known concentrations of reference compounds (fluorescein and luteinising hormone-releasing hormone; LHRH) through measured sections of selected regions (jejunum, caecum, proximal colon) of the intestinal tract of 19 possums, over a 2-h period. Plasma concentrations of the compounds, which were perfused either with or without co-administration of a permeation enhancer (sodium deoxycholic acid; SDA), were determined in the perfusion effluent, peripheral and in some instances in the pre-hepatic circulation by spectrofluorometry (fluorescein) or radio-immunoassay (LHRH). Pharmacokinetic parameters of both compounds in the possum were determined over a period of up to 4 h in a further 30 animals (fluorescein, n=6; LHRH n=24), from their plasma profiles following intravenous (I/V) administration of a bolus dose.

RESULTS: In animals perfused with 25 mg/ml fluorescein (Perfusion Experiment (PE) 1), the mean plasma concentration was 2.8 (SE 0.12) µg/ml in post-hepatic blood samples. When possums were perfused with 2.5 mg/ml fluorescein and 7 µg/ml LHRH (PE 2), mean plasma concentrations were 0.3 (SE 0.01) and 7.8 (SE 1.64) µg/ml fluorescein and 0.1 (SE 0.02) and 6.3 (SE 0.45) ng/ml LHRH, in the absence and presence of permeation enhancer, respectively. There was a poor correlation between pre-hepatic and post-hepatic concentrations.

CONCLUSIONS: The single-pass in situ perfusion technique provided a useful model for investigating basic information on the absorption of biocontrol agents across the intestinal tract of possums, but had limitations that must be recognised.  相似文献   

Survival advantage of cyromazine‐resistant sheep blowfly larvae on dicyclanil‐ and cyromazine‐treated Merinos     

GW Levot  BJ Langfield  DJ Aiken 《Australian veterinary journal》2014,92(11):421-426

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Comparison of the measurement of heart rate in adult free‐range chickens (Gallus domesticus) by auscultation and electrocardiography     

CF Smith  BJ Gavaghan  D McSweeney  V Powell  A Lisle 《Australian veterinary journal》2014,92(12):509-511

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