Pathology of experimentally-induced, acute toxoplasmosis in macropods

SUMMARY Thirteen Tammar wallabies (Macropus eugenii) were dosed orally with 500, 1000 or 10 000 oocysts of Toxoplasma gondii, as part of a vaccination trial. Eleven animals died of acute toxoplasmosis 9 to 15 days after challenge. The lesions were similar in all animals, consisting of foci of necrosis and inflammation in the intestines, lymphoid tissue, adrenal cortex, heart, skeletal muscle and brain, and severe generalised pulmonary congestion and oedema. Free and intracellular tachyzoites of Toxoplasma were associated with the lesions. The remaining 2 animals had shown no signs of disease when euthanased four months after challenge. Small, focal, non-suppurative inflammatory lesions were seen in brain, heart and skeletal muscle of these animals and chronic Toxoplasma infection was confirmed by mouse inoculation.     

Gender,caponization and exogenous estrogen effects on lipids,bone and blood characteristics in Taiwan country chickens

This study investigated gender, caponization and exogenous estrogen effects on lipids, bone and blood characteristics in Taiwan country chickens. Thirty male chickens were caponized at 8 weeks (capons); 15 capons were injected with estrogen (5 mg/bird estradiol 3‐benzoate) every 2 weeks from 8 to 28 weeks, and 15 sham‐operated male (shams) chickens and 15 females were selected for this trial. The results showed that the shams had lower relative abdominal and chest subcutaneous fat than females (P < 0.05). The estrogen‐treated capons had greater relative abdominal and chest subcutaneous fat than shams and capons (P < 0.05), which might result from higher blood very low‐density lipoproteins and triacylglycerol concentrations (P < 0.05). Caponization could dramatically increase relative abdominal fat (506%; P < 0.05). The shams had higher tibia weight and biomechanical properties, such as maximum bone strength and bending moment values than the capons (P < 0.05). Tibia biomechanical properties were reduced by estrogen treatment (P < 0.05). The females obtained the lowest biomechanical value in all treatments (P < 0.05). Histological examination revealed cavity formation in the cortical bone of estrogen‐treated capons and female chickens, which suggested that estrogen reduced bone biomechanical properties by destroying its structural integrity.     

A national serological survey to verify Australia's freedom from porcine reproductive and respiratory syndrome

Objective To provide serological data to support Australia's claim of freedom from porcine reproductive and respiratory syndrome.
Design A national serological survey was designed to provide 99% confidence of detecting at least one infected pig herd in Australia, assuming that at least 5% of herds would have been exposed to porcine reproductive and respiratory syndrome virus and that at least 25% of the 'finisher' pigs in these herds would have antibodies to the virus.
Procedure A two-stage testing regime was used. All samples were tested with a commercially available enzyme-linked immunosorbent assay. If assay reactions were found, all samples from the herd were to be tested using the indirect immunofluorescence antibody assay.
Results Of the 875 samples from 163 herds from all States in Australia, there was some evidence of reactivity in only four samples from four herds on the enzyme-linked immunosorbent assay. Further testing using the indirect immunofluorescence antibody assay according to the study protocol demonstrated that the reactions were not due to the presence of specific porcine reproductive and respiratory syndrome virus antibodies in the sera.
Conclusion The results of this study support the view that Australian pigs are free of porcine reproductive and respiratory syndrome virus.     

Nondestructive evaluation techniques for assessing dynamic modulus of elasticity of moso bamboo (Phyllosachys edulis) lamina

Bamboo, an extensively used material in Asia, is becoming an increasingly available structural (e.g., flooring and furniture) material in Taiwan. The bending strength and dynamic modulus of elasticity of moso bamboo (Phyllosachys edulis) laminae were investigated using ultrasonic-wave and drilling resistance techniques. The strength quality of bamboo was reduced after steaming treatment and was significantly affected by node characteristics. The transverse variations of the mean drilling resistance value (R) gradually increased outward from the bamboo cavity layer. There were very significant positive relationships among density (ju), the drilling resistance value (R), the dynamic modulus of elasticity (Eb), the modulus of elasticity (MOE), and the modulus of rupture (MOR), although the coefficients of determination were small. Combining ultrasonic-wave and drilling resistance techniques is efficient in estimating and establishing the dynamic modulus of elasticity (REb). Values of REb for moso bamboo increased with increasing ju, R, Eb, MOE, and MOR, and the relationships could each be represented by positive linear regression formulas.     

Fire retardancy and CO/CO2 emission of intumescent coatings on thin plywood panel with waterborne vinyl acetate-acrylic resin

Using intumescent coatings on wood-based materials is an effective method for fire safety. Previous studies have demonstrated that the formulation of components strongly influences the performance of coatings. This study investigated the effect of intumescent formulation of vinyl acetate-acrylic coating on flame retardancy of plywood. The fire retardancy of materials was assessed by both heat release and CO and CO₂ emissions. The CO and CO₂ emissions have not been used frequently to rank materials; the highly toxic CO and CO₂ may cause most fire fatalities. The fire retardancy of coatings on plywood was assessed by a cone calorimeter. Total heat release and time to peak heat release rate were the two primary parameters. The data show that low contents of binder resin (BR) and foam producing substance (FPS) decreased total heat release and lengthened time to peak heat release rate. Additionally, low BR and FPS content can form an ideal char layer. The ideal char layer significantly decreased the CO and CO₂ emission. The mechanism to achieve better fire performance was verified by thermogravimetrical analysis exhibiting lower weight loss. Moreover, evaluated by ³¹P NMR, the low BR and FPS content can extend the survival duration of phosphor-carbonaceous chars. The results provide information for designing vinyl acetate-acrylic emulsion coating.     

Effects of intumescent formulation for acrylic-based coating on flame-retardancy of painted red lauan (<Emphasis Type="Italic">Parashorea</Emphasis> spp.) thin plywood

Acrylic emulsion based painted red lauan plywood (Parashorea spp.) is most commonly used for indoor furnishings. This study investigated the enhancement of the fire retardance of painted plywood by interaction among four major components of intumescent formulation: (1) acrylic emulsion resin as binder resin (BR), (2) pentaerythritol as carbonizing substance (CS), (3) melamine as foam producing substance (FPS) and (4) ammonium polyphosphate as dehydrating agent (DA). Effects of changing BR/CS ratios (designated as FRA series) and FPS/DA ratios (designated as FRM series) on flame-retardance of painted plywood were investigated using a cone calorimeter. The intumescent formulation significantly enhanced fire retardancy of painted plywood by exhibiting lower peak release rates and longer times to reach peak release rates, compared with uncoated plywood (UP) panel and plywood panel solely coated with acrylic emulsion resin. Lower BR content in the FRA series and lower FPS content in the FRM series were shown to enhance flame retardancy of painted plywood. The positive correlation between total heat release values under increasing combustion duration and incremental changes of BR and FPS contents in two series further verified the above findings. Consistent with the observed flame retardancy enhancement of painted plywood, lower heats of combustion and weight losses for paints in the FRM series were also identified by oxygen bomb calorimeter measurements and thermogravimetrical analysis. Infrared analysis of the chars indicated the formation of phosphate ester linkages with the lowest BR content in the FRA series and the lowest FPS content in the FRM series showing superior enhancements of flame retardancy for painted red lauan plywood.     

Vegetation recovery monitoring and assessment at landslides caused by earthquake in Central Taiwan

Massive landslides, caused by the catastrophic Chi-Chi earthquake in 1999, occurred at the Jou-Jou Mountain area in the Wu-Chi basin, Taiwan. Multi-temporal satellite images and digital elevation models coupled with GIS were used to process the vegetation index analysis for identifying landslide sites and calculating the vegetation recovery rate (VRR). Topographic information for these areas was extracted. Eight hundred twenty-nine hectares of landslide area was extracted from multi-date NDVI images by combining the image differencing method with the change detection threshold. Over 2 years of monitoring and assessing, the vegetation recovery rate reached 58.93% original vegetation regeneration in the landslide areas. Soil moisture is one of the most important environmental factors for vegetation recovery in the landslide sites. The analyzed results provide very useful information for decision making and policy planning in the landslide area.