Mercury Flux Measurements over Air and Water in Kejimkujik National Park,Nova Scotia

Mercury flux measurements were conducted at two lakes and three soil sites in Kejimkujik National Park, located in the eastern Canadian province of Nova Scotia. One of the lakes had high levels of both mercury and Dissolved Organic Carbon (DOC). Two of the soil sites were located under the forestcanopy, while the other was in a small clearing surrounded by forest. Flux measurements were performed using the dynamic chamber method. Mercury concentrations in the air were measured with a TEKRAN mercury analyzer. Mercury fluxes over the two lakes were most strongly correlated with solar radiation, although the flux was also significantly correlated with water temperature, air temperature, and negatively correlated with relative humidity. The flux from the high DOC lake (Big Dam West) was especially high when the conditions were both sunny and windy (wind speed greater than 1.3 m s^-1) and the average flux measured was 5.4 ng m^-2 h^-1. The mercury flux from this lake was wellparameterized in terms of a simple expression involving solar radiation and a nonlinear dependence on wind speed. The flux measured from the low DOC lake (North Cranberry) tended to be lower than from the high DOC lake. The averageflux measured was 1.1 ng m^-2 h^-1, but was again strongly correlated with solar radiation. The flux was low during windy conditions in the absence of sunlight, suggesting that wind enhances mercury evasion from lakes only in the presence of solar radiation. Mercury fluxes measured over the soil sites tended to be smaller than those over water (a range of –1.4–4.3 ng m^-2 h^-1). At one of the forest sites, mercury flux was very strongly correlated with 0.5 cm soil temperature, and this dependence was well described by an Arrhenius-typeexpression with an activation energy of 14.6 kcal^-1 mole, quite close to the heat of vaporization of mercury (14.5 kcal^-1 mol^-1 at 20 °C). At the clearing, where there was direct exposure to the sun, the mercury flux was most strongly correlated with solar radiation.     

Gallbladder sludge on ultrasound is predictive of increased liver enzymes and total bilirubin in cats

The purposes of this retrospective study were to assess the prevalence of gallbladder sludge (GBS) in a population of cats presented for abdominal ultrasound in a teaching hospital and to determine its association with increased serum alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total bilirubin (TB). Gallbladder sludge was detected in 152 (14%) of the cats undergoing abdominal ultrasound between 2004 and 2008. This population was compared to a control group of 32 cats without GBS. Alanine aminotransferase, ALP, and TB mean values were significantly higher in cats with GBS than in controls (P ≤ 0.0005) and odds for increased values in cats with GBS were 4.2 [95% confidence interval (CI): 1.6 to 11.0], 9.5 (95% CI: 2.2 to 41.7), and 4.1 (95% CI: 1.5 to 11.5), respectively (P ≤ 0.007). In conclusion, GBS is an uncommon ultrasonographic finding in cats that is predictive of increased liver enzymes and TB. More studies are needed to establish potential links between GBS and hepatobiliary disease in cats.     

Xenon as a nucleophile in gas-phase displacement reactions: formation of the methyl xenonium ion

Xenon undergoes reaction with protonated methyl fluoride in the gas phase to form abundant quantities of the stable methyl xenonium ion, CH(3)Xe(+). Estimated values for the xenon-carbon and krypton-carbon bond strengths in the rare gas-methyl molecular ions are 43 +/- 8 and 21 +/- 15 kilocalories per mole, respectively.     

Comparison of radiography and ultrasonography to detect osteochondrosis lesions in the tarsocrural joint: A prospective study

Reasons for performing study: Lesions located on the medial malleolus of the tarsocrural joint can be difficult to image radiographically. Ultrasonography allows evaluation of articular cartilage and subchondral bone. Objectives: To compare dorso30° lateral‐plantaromedial‐oblique (DL‐PlMO) and dorso45° views to detect lesions on the medial malleolus, to validate the use of ultrasonography to show lesions in the tarsocrural joint and to compare its sensitivity to radiography. Methods: Tarsocrural joints (n = 111) with osteochondrosis were evaluated ultrasonographically and radiographically prior to arthroscopic lesion debridement. A complete radiographic examination was made and the best view to detect each lesion recorded. Longitudinal and transverse ultrasonography of the dorsal aspect of the joint was performed and the best scan plane to image each lesion recorded. Results: There were 94 joints with lesions on the distal intermediate ridge of tibia, 24 with lesions on the medial malleolus, and 4 with lesions on the lateral trochlear ridge. The sensitivity of radiography to detect lesions on the medial malleolus and distal intermediate ridge of tibia was 71 and 96%, respectively. Eighty‐two percent of lesions on the medial malleolus were better imaged on dorso30° view. The sensitivity of ultrasonography to detect lesions on the medial malleolus and distal intermediate ridge of tibia was 83 and 98%, respectively. Ultrasonography was significantly more sensitive than radiography to detect lesions on the medial malleolus and distal intermediate ridge of tibia. Conclusion: Dorso30° lateral‐plantaromedial‐oblique view was the best to image lesions on the medial malleolus. Ultrasonography was a valuable diagnostic tool to diagnose lesions in the tarsocrural joint and was more sensitive than radiography for lesions located on the medial malleolus and distal intermediate ridge of tibia. Clinical relevance: Radiographic examination should include a dorso30° view for detection of lesions on the medial malleolus and ultrasonography should be considered to diagnose osteochondrosis in the tarsocrural joints.     

Effects of oral administration of meloxicam,carprofen, and a nutraceutical on thyroid function in dogs with osteoarthritis

The purpose of this study was to evaluate the effect of the administration of meloxicam; carprofen; and a slow-acting disease modifying osteoarthritis agent, that contains chondroitin sulfate, purified glucosamine, and manganese ascorbate (CS-G-M), on thyroid function in dogs. Forty-six healthy (except for osteoarthritis) euthyroid dogs were blindly assigned to 3 treatment groups: meloxicam, carprofen, and CS-G-M. Each group received the recommended dose of the drug for 60 days. Sixteen other osteoarthritic euthyroid dogs, which received a placebo, were used as a control group to validate the study. For all groups, blood samples were collected on days 0, 30, and 60 to evaluate the serum total and free thyroxine, and endogenous thyrotropin concentrations. There were no significant differences among the treatment groups at each time or within each group over a 60-day period for all parameters. Moreover, none of these values were within the hypothyroid range. Based on the results of this study, the administration of meloxicam, carprofen, and CS-G-M did not affect canine thyroid function evaluation.     

Comparison of an alcohol-based hand rub and water-based chlorhexidine gluconate scrub technique for hand antisepsis prior to elective surgery in horses

This prospective clinical study evaluates the effectiveness of an alcohol-based hand rub (Avagard™) for pre-surgical hand antisepsis in an equine hospital and compares it with traditional scrubbing technique using 4% chlorhexidine gluconate sponges and water. Prior to elective surgery, 3 board-certified surgeons were randomly assigned to hand antisepsis with either technique. Culture samples of each hand were taken at 4 times: before and after neutral soap hand wash, after scrub or rubbing technique, and after surgery. There was no significant difference in mean bacterial colony forming units between scrub and rub techniques over the 3 time periods (P = 0.6), controlling for initial counts. One horse from the scrub group had a skin incision infection following stifle arthroscopy; this was resolved with medical treatment. The alcohol-based hand rub is equivalent in efficacy for pre-surgical hand antisepsis to traditional water-based scrubs in an equine hospital setting.     

Limited inhibition of nitrous oxide reduction in soil in the presence of acetylene

Anaerobic flasks with two different soils contained microorganisms which effectively reduced NO₃⁻ to N₂ in the absence of C₂H₂ and in the presence or absence of CO₂. In the presence of C₂H₂, the microorganisms reduced NO₃⁻ to N₂O and the further reduction of N₂O to N₂ was temporarily inhibited. This was shown for two partial pressures of C₂H₂ (0.1 kPa and 1.0 kPa). However. after a maximum of 168 h, microorganisms were able to reduce N₂O to N₂ in the presence of C₂H₂. This was shown in the presence of CO₂ for both partial pressures of C₂H₂ and in the absence of CO₂ for 1.0 kPa C₂H₂. The absence of CO₂ delayed the complete reduction of N₂O. Microorganisms which had reduced N₂O in the presence of C₂H₂ retained this ability for at least 3 days after the original atmosphere containing C₂H₂ had been removed.