Imaging of intermittency in ripple-wave turbulence

The dynamics of a fluid surface filled with high-amplitude ripples were studied with a technique (diffusing light photography) that resolves the height at all locations instantaneously. Even when nonlinearities are strong enough to generate a (Kolmogorov) cascade from long wavelength (where energy is input) to shorter wavelength, the resulting turbulent state contains large coherent spatial structures. The appearance of these structures in a thermal equilibrium state (with the same average energy) would be highly improbable.     

Predatory Dinosaurs from the Sahara and Late Cretaceous Faunal Differentiation

Late Cretaceous (Cenomanian) fossils discovered in the Kem Kem region of Morocco include large predatory dinosaurs that inhabited Africa as it drifted into geographic isolation. One, represented by a skull approximately 1.6 meters in length, is an advanced allosauroid referable to the African genus Carcharodontosaurus. Another, represented by a partial skeleton with slender proportions, is a new basal coelurosaur closely resembling the Egyptian genus Bahariasaurus. Comparisons with Cretaceous theropods from other continents reveal a previously unrecognized global radiation of carcharodontosaurid predators. Substantial geographic differentiation of dinosaurian faunas in response to continental drift appears to have arisen abruptly at the beginning of the Late Cretaceous.     

Ascorbic acid oxidation in sucrose aqueous model systems at subzero temperatures

The reduction of Tempol by ascorbic acid in concentrated sucrose solutions was measured by electron paramagnetic resonance (EPR) at temperatures ranging from 16 to -16 degrees C. This method allowed the determination of the rate constants (k) of this fast reaction, by recording the Tempol reduction as a function of time. The two reactants were initially separated and had to migrate for the reaction to occur. The experimental findings were compared with predicted values according to the equation for diffusion-controlled reaction proposed by Atkins. The experimental reaction rate constants were observed to be lower than the calculated ones. However, the experimental values were found to be controlled by the temperature and viscosity changes of the reaction media, as expected for a diffusion-controlled reaction.     

Indices of renal function: reference values in normal horses

Urine and blood samples were taken at the same time from normal adult horses presented for routine investigations to establish reference values for a variety of parameters reported to be useful in the clinical evaluation of renal function. Blood biochemical values were consistent with previous studies and had well-defined normal ranges. Parameters representing urine concentration and electrolyte excretion however, varied widely reflecting the ability of the healthy kidney to change the composition of urine in response to differences in environment and management. Percent creatinine clearance ratios for potassium in particular were lower than those reported in normal horses in previous studies. Rational interpretation of these latter measurements should accept a wide range of normal values and management conditions must be considered in this interpretation.     

Insulin sensitivity decreases with obesity, and lean cats with low insulin sensitivity are at greatest risk of glucose intolerance with weight gain

This study quantifies the effects of marked weight gain on glucose and insulin metabolism in 16 cats which increased their weight by an average of 44.2% over 10 months. Significantly, the development of feline obesity was accompanied by a 52% decrease in tissue sensitivity to insulin and diminished glucose effectiveness. In addition, glucose intolerance and abnormal insulin response occurred in some cats. An important finding was that normal weight cats with low insulin sensitivity and glucose effectiveness were at increased risk of developing impaired glucose tolerance with obesity. High basal insulin concentrations or low acute insulin response to glucose also independently increased the risk for developing impaired glucose tolerance. Male cats gained more weight relative to females and this, combined with their tendency to lower insulin sensitivity and higher insulin concentrations, may explain why male cats are at greater risk for diabetes. Results suggest an underlying predisposition for glucose intolerance in some cats, which is exacerbated by obesity. These cats may be more at risk of progressing to overt type 2 diabetes mellitus.     

Mucopolysaccharidosis type VI in a Miniature Poodle-type dog caused by a deletion in the arylsulphatase B gene

Abstract

AIM: To investigate and characterise an inborn error of metabolism in a dog with skeletal and ocular abnormalities.

METHODS: A 2.5-year-old small male Miniature Poodle-like dog was presented with gross joint laxity and bilateral corneal opacities. Clinical examination was augmented by routine haematology, serum chemistry, radiographs, pathology, enzymology and molecular genetic studies. Euthanasia was requested when the dog was 3 years of age because of progressively decreasing quality of life.

RESULTS: Radiology revealed generalised epiphyseal dysplasia, malformed vertebral bodies, luxation/subluxation of appendicular and lumbosacral joints with hypoplasia of the odontoid process and hyoid apparatus. These clinical and radiographic findings, together with a positive urinary Berry spot test for mucopolysaccharides, and metachromatic granules in leucocytes, were indicative of a mucopolysaccharidosis (MPS), a lysosomal storage disease. Histological lesions included vacuolation of stromal cells of the cornea, fibroblasts, chondrocytes, macrophages and renal cells. The brain was essentially normal except for moderate secondary Wallerian-type degeneration in motor and sensory tracts of the hind brain. Dermatan sulphate-uria was present and enzymology revealed negligible activity of N-acetylgalactosamine-4-sulphatase, also known as arylsulphatase B, in cultured fibroblasts and liver tissue. A novel homozygous 22 base pair (bp) deletion in exon 1 of this enzyme's gene was identified (c.103_124del), which caused aframe-shift and subsequent premature stop codon. The “Wisdom pure breed-mixed breed” test reported the dog as a cross between a Miniature and Toy Poodle.

CONCLUSIONS: The clinicopathological features are similar to those of MPS type VI as previously described in dogs, cats and other species, and this clinical diagnosis was confirmed by enzymology and molecular genetic studies. This is an autosomal recessively inherited lysosomal storage disease.

CLINICAL RELEVANCE: The prevalence of MPS VI in Miniature or Toy Poodles in New Zealand and elsewhere is currently unknown. Due to the congenital nature of the disorder, malformed pups may be subject to euthanasia without investigation and the potential genetic problem in the breed may not be fully recognised. The establishment of a molecular genetic test now permits screening for this mutation as a basis to an informed breeding policy.