The Source of Anthropogenic Heavy Metals in Fluvial Sediments of a Rural Catchment: Coxs River,Australia     

Birch  Gavin  Siaka  Made  Owens  Christopher 《Water, air, and soil pollution》2001,126(1-2):13-35

A serious health scare involving thesupply of drinking water to Sydney, Australia hasrecently focussed attention on the environmentalstatus of river catchments of the main reservoir, LakeBurragorang. Although the Coxs River – a majorcatchment of Lake Burragorang – comprises mainlyforests and grazing land, it supports a moderate sizedtown, power stations and coal mines. The heavy metal content of stream-bed sedimentscharacterises environmental impact in this ruralcatchment and sources of contamination. Sediment in acreek flowing through a country town (population 12 000) is markedly enriched in Cr, Pb and Zn (3×, 18×and 52×, respectively) over background, probably dueto a long history of metal-based industry. The highestCu, Pb and Zn concentrations (204, 332 and2460 μg g^-1, respectively) in fluvialsediment in the town are, however associated withdischarges from a sewage treatment plant. Twocoal-based power stations in the catchment contributeconsiderable Cu and Ni (maximum concentrations 562 and157 μg g^-1, respectively) to ambient fluvialsediments, possibly from cooling towers and coalstorage areas. The highest Co and Cr concentrations(113 and 490 μg g^-1) in fluvial sediments ofthis catchment are associated with coal-miningactivities. Selective extraction indicates that about50% of the anthropogenic fraction may bebioavailable, whereas sequential extraction proceduressuggest that <25% is associated with the easilyexchangeable/adsorbed phase.Two dams restrict the migration of heavy metals downthe Coxs River and sediment discharging into LakeBurragorang is low in metals.  相似文献   

The characterization of cycad palm toxicosis and treatment effects in 130 dogs     

BB Lake  T Edwards  G Atiee  R Stone  L Scott 《Australian veterinary journal》2020,98(11):555-562

The purpose of this retrospective study is to characterize the clinical signs, laboratory values, treatment modalities and mortality outcomes related to cycad palm toxicosis in dogs and to identify medical interventions that potentially correlate with mortality. Dogs with confirmed cycad palm ingestion were identified by reviewing medical records from two private veterinary referral centres for key terms and phrases indicative of cycad palm toxicosis. Of 130 dogs included, 107 (82.3%) presented with clinical signs. A total of 2 (1.5%) died and 14 (10.8%) were euthanized. Diarrhea, lethargy and mortality were all associated with an elevated initial alanine transaminase (ALT) concentration. Overall mortality was 12.3%, with a significantly higher proportion of dogs with an ALT concentration <125 U/L surviving compared to dogs with an elevated ALT concentration. Treatment with activated charcoal reduced the odds of death among all dogs by 82% and was even more protective among dogs with an elevated initial ALT concentration. Among dogs that had an initial platelet count performed, the presence of thrombocytopenia (<200,000/μL) was a negative prognostic indicator and was associated with a significant increase in mortality. Given the high mortality rates reported for cycad palm toxicosis, it is imperative to identify early clinical indicators of mortality as well as treatments that reduce mortality.  相似文献   

Background and summary of this issue on sediment linkages     

Philip N. Owens 《Journal of Soils and Sediments》2007,7(5):273-276

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Processing of equine bone marrow using the automated MarrowXpress System: RBC depletion, volume reduction, and mononuclear cell recovery     

Owens SD  Burges J  Johns JL  Carrade DD  Galuppo LD  Librach F  Borjesson DL 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2011,40(4):444-449

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Forced Diffusion soil flux: A new technique for continuous monitoring of soil gas efflux     

David Risk  Nick NickersonChance Creelman  Gordon McArthurJennifer Owens 《Agricultural and Forest Meteorology》2011,151(12):1622-1631

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Developmental alterations in the regulation of glucagon and insulin secretion in Holstein calves     

S W Owens  J L Sartin  R J Kemppainen  K A Cummins  F F Bartol  M A Bowman 《American journal of veterinary research》1986,47(2):263-269

Twenty-one Holstein bull calves were randomly assigned at birth to 3 groups. Two groups (each of 7 calves) were raised as follows: fed a milk diet alone or fed milk with grain supplementation after 2 weeks of age; studies were done when calves reached 4 weeks of age. The 3rd group was fed on milk with grain supplementation until weaning after which the calves were maintained on grain and pasture. These calves (older calves) were studied at 12 weeks of age. Either propionate (0.28 mmol/kg) or glucose (0.56 mmol/kg) was injected IV in a random order. Samples of blood were obtained from the calves before and immediately after injections were done and at 2, 5, 10, 15, 30, 45, and 60 minutes after secretagogue injection. Plasma was examined for glucose by a glucose oxidase procedure and for immunoreactive insulin (IRI) and glucagon (IRG) by radioimmunoassay. The IRI response to the injection of glucose was greater in older calves (P less than 0.02). Patterns of IRI secretion, as determined by heterogeneity of regression, showed age differences for both secretagogues (P less than 0.05). Base-line IRG was greater in milk/grain-fed calves than in milk-fed calves (P less than 0.05). Mean IRG response to propionate injection was higher (P less than 0.05) in milk/grain-fed calves than in milk-fed calves. Plasma glucose concentration increased in older calves, but decreased in milk-fed calves after propionate injection. The data indicate that maturation in the ruminant is accompanied by altered regulation of insulin and glucagon secretion.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Limits to starch digestion in the ruminant small intestine   总被引：7，自引：0，他引：7  

F N Owens  R A Zinn  Y K Kim 《Journal of animal science》1986,63(5):1634-1648

Site and extent of starch digestion by ruminant animals varies with species, grain type and processing method. Based on a review of 40 different experiments with cattle, between 18 and 42% of the dietary starch from corn and sorghum grains fed to cattle reaches the small intestine for digestion. With more extensive grain processing, a smaller quantity of starch reaches the small intestine. In the small intestine, from 47 to 88% of the presented starch is digested, while in the large intestine, 33 to 62% of the presented starch is digested. Though limits to digestion in and absorption from the small intestine can be demonstrated by infusing starch and glucose into the duodenum, enzymatic capacity does not appear to limit intestinal starch digestion since no plateau in the amount of starch disappearing from the small intestine is detected with typical diets. Yet, extent of digestion is incomplete. Other factors, such as time and surface exposure may limit small intestinal digestion of starch. Processing methods to reduce particle size or alter the protein matrix, which cements starch granules together, will increase the extent of digestion both in the rumen and in the small intestine. Performance data from growing cattle fed processed corn and sorghum grains indicate that starch was used 42% more efficiently if it was digested in the small intestine rather than in the rumen. Though total tract starch digestibility is of primary concern, results support the concept that energetic efficiency of growing ruminants is greater if starch is digested in the small intestine rather than in the rumen.  相似文献   

INTRACRANIAL RING ENHANCING LESIONS IN DOGS: A CORRELATIVE CT SCANNING AND NEUROPATHOLOGIC STUDY     

Michael  Wolf  Dr. Vet. Med.  Vince  Pedroia  DVM  Robert J.  Higgins  BVSc  PhD  Philip D.  Koblik  DVM  MS  Jane M.  Turrel  DVM  MS  Jerry M.  Owens  DVM 《Veterinary radiology & ultrasound》1995,36(1):16-20

This retrospective analysis of 15 dogs with postcontrast ring enhancing brain lesions, each detected by a single Computed Tomography [CT] examination, searched for any association between their CT appearance and the pathologic diagnosis. In a subgroup of these dogs [n = 7] necropsied within 2 days of the last CT scan, we evaluated whether there was any anatomic correlation between the ring zone and the histopathologic features of the lesions. Our study consisted of eight dogs with primary brain tumors [3 meningiomas, 3 astrocytomas, 1 mixed glioma, 1 oligodendroglioma], 4 with metastatic brain tumors [2 fibrosarcomas, 1 mammary carcinoma, 1 melanoma] and 3 with non-neoplastic brain lesions [2 intraparenchymal hemorrhages, 1 pyogranulomatous meningoencephalitis]. The overall size and shape of the contrast enhancing CT lesions, as well as the thickness, surface texture and degree of enhancement of the ring were subjectively evaluated. No association was found between the CT lesion characteristics and the pathologic diagnosis. In the sub-group of dogs euthanatized within 2 days of the CT examination, distinct histologic features which anatomically correlated with the zone of ring enhancement were found in 3 of 7 lesions. The findings of this study are consistent with those of ring-enhancing lesions in people, and indicates that CT ring enhancement is a non-specific phenomenon which can occur in a variety of neoplastic and non-neoplastic lesions in the dog.  相似文献   

Response of heifer mammary gland macrophages and neutrophils to interferon-gamma stimulation in vitro.          下载免费PDF全文

G H Quiroga  W E Owens    S C Nickerson 《Canadian journal of veterinary research》1993,57(3):212-214

The phagocytic and killing abilities of heifer mammary gland macrophages (M phi) and neutrophils were evaluated after exposure to recombinant bovine interferon-gamma (rBoIFN-gamma) stimulation in vitro. Macrophages or neutrophils were cultured for 2 h with 0, 10(2), 10(4) and 10(5) units rBoIFN-gamma/mL. Phagocytosis assays were performed by incubation with Staphylococcus aureus at a leukocyte:bacteria ratio of 1:10. After 45 min, cells were stained with acridine-orange and phagocytic and killing abilities were determined. Although rBoIFN-gamma had no effect on M phi phagocytic activity, neutrophil phagocytic activity after incubation in 10(4) units rBoIFN-gamma (41.62%) was significantly higher than 0 (25.24%) or 10(2) units rBoIFN-gamma (24.73%). Neutrophil and M Phi killing abilities were not affected by any dose of rBoIFN-gamma. Results suggested that rBoIFN-gamma promoted neutrophil phagocytic activity, but did not affect neutrophil killing or overall M phi function in vitro.  相似文献   

Faecal contamination of watercourses from farm waste disposal for three sites in the UK with contrasting soil types     

L.K. Deeks  M. McHugh  P.N. Owens 《Soil Use and Management》2005,21(2):212-220

Abstract. Despite considerable investment, some UK bathing waters fail to comply with mandatory standards as defined by the EU Bathing Water Directive (76/160/EEC). Continued non-compliance has been associated with diffuse sources of faecal indicator organism (FIO) contamination, in particular those deriving from agricultural land. This paper examines concentrations of FIOs in surface, subsurface and instream water samples at field sites considered to pose a high potential risk of FIO contamination. Quality of samples was compared with FIO standards for bathing water compliance in the UK. FIO concentrations exceeding mandatory and guideline standards were recorded frequently at all sites. In freely draining soils, FIO mobilization by rainfall was predominantly via subsurface flow, with occasional surface water flow linked to intensive rainfall events. In slowly permeable soils, surface mobilization of FIOs predominated, with the occurrence of limited subsurface samples linked to seasonal desiccation cracking within the soil, and to intense rainfall events. Watercourse FIO concentrations were significantly increased as the stream passed-by fields with freely draining soils. The data imply a generally higher risk of FIO transfer from freely draining soils and occasional increased risk from less permeable soils due to temporal changes in soil structure and rainfall intensity.  相似文献