Nonlinear Optics for High-Speed Digital Information Processing

Recent advances in developing nonlinear optical techniques for processing serial digital information at high speed are reviewed. The field has been transformed by the advent of semiconductor nonlinear devices capable of operation at 100 gigabits per second and higher, well beyond the current speed limits of commercial electronics. These devices are expected to become important in future high-capacity communications networks by allowing digital regeneration and other processing functions to be performed on data signals "on the fly" in the optical domain.     

The conservation value of oil palm plantation estates, smallholdings and logged peat swamp forest for birds

The expansion of industrial oil palm cultivation threatens tropical biodiversity globally, especially in developing countries. Driven by plans to generate economic revenue, large-scale plantations are emerging in Southeast Asia, Africa and Brazilian Amazon. However, the ecological impacts of the sector are poorly studied with respect to oil palm management system, and recommended conservation measures are based on limited data. We studied avifauna in oil palm landscapes in Peninsular Malaysia under different management systems (large plantation estates versus smallholdings) and age classes (uniform age versus mixed-age stands). We sampled 41 large plantation estates and 14 smallholdings, as well as 20 sites in an extensively logged peat swamp forest, the type of natural forest prior to conversion to oil palms. Compared with logged peat swamp forest, our results showed that forest conversion to oil palm cultivation may have eliminated 48-60% of bird species. We also found: (i) plantation estates and smallholdings supported similar bird assemblages but the latter supported significantly more species (P = 0.007); and (ii) despite reduced species richness in oil palm landscapes, we found high abundance of some individual bird species in specific types of stands including some forest, migratory, and wetland species. Conversion of natural forest to oil palm landscapes should not occur in the future through clearing of primary or secondary native forests. To complement conventional conservation approaches (e.g. the establishment of protected areas) in palm oil-producing countries, existing plantation estates and smallholdings should be managed in ways to promote improved conservation outcomes, although oil palm landscapes maintained a fraction of the original forest biodiversity. Managing habitat heterogeneity at both a local and a landscape-level is highly recommended in oil palm landscapes to maintain and/or enhance avian biodiversity.     

Anomeric specificity of glucose-stimulated insulin release: evidence for a glucoreceptor?

The effects on insulin secretion of alpha and beta anomers of D-glucose were studied in the in vitro perfused rat pancreas. Both phases of insulin release showed consistent stereospecificity for alpha-glucose; this specificity indicates an action of glucose independent of intracellular glucose metabolism.     

Trace metals as biomarkers for eumelanin pigment in the fossil record

Well-preserved fossils of pivotal early bird and nonavian theropod species have provided unequivocal evidence for feathers and/or downlike integuments. Recent studies have reconstructed color on the basis of melanosome structure; however, the chemistry of these proposed melanosomes has remained unknown. We applied synchrotron x-ray techniques to several fossil and extant organisms, including Confuciusornis sanctus, in order to map and characterize possible chemical residues of melanin pigments. Results show that trace metals, such as copper, are present in fossils as organometallic compounds most likely derived from original eumelanin. The distribution of these compounds provides a long-lived biomarker of melanin presence and density within a range of fossilized organisms. Metal zoning patterns may be preserved long after melanosome structures have been destroyed.     

Enrichment of channel catfish (Ictalurus punctatus) fillets with conjugated linoleic acid and omega-3 fatty acids by dietary manipulation

An experiment was conducted in aquaria with channel catfish (Ictalurus punctatus) to determine the efficacy of augmenting fillets with conjugated linoleic acid (CLA) and omega-3 highly unsaturated fatty acids (n − 3 HUFA) by feeding diets amended with products containing high levels of these nutrients. Refined menhaden fish oil at 1.5% of diet supplied the n − 3 HUFA. CLA was used at dietary levels of 0.5% and 1% with a preparation that contained approximately 65% isomers of CLA. Corn oil was added to the basal diet at maximum inclusion level for added lipids of 3% for the control diet and to adjust total added lipid content of the other diets to 3%. Average initial body weight was 57.39 ± 0.25 g/fish. Six experimental diets were fed twice daily to four replicate aquaria for six weeks. At that time, fish were group weighed for determination of weight gain and feed conversion. Fillets of six fish per aquarium were recovered and stored at − 80 °C for moisture and total lipid analyses, fatty acid analysis, and sensory evaluation. Results showed feed consumption and feed conversion did not differ (P > 0.05). Significantly (P < 0.05) greater body weight gains were observed only for fish fed the diets with two combinations of CLA and 1.5% fish oil compared to fish fed the diet containing 0.5% CLA and corn oil. Fillet n − 3 HUFA levels were significantly (P < 0.05) elevated for fish fed diets containing fish oil when compared to n − 3 HUFA of fillets of fish fed diets containing either corn oil or CLA and corn oil. Similarly, fillets from fish fed diets amended with CLA contained substantial amounts of CLA of up to 6.4% of total lipids. Fillets from fish fed corn oil or fish oil diets had no CLA. Taste panel evaluation indicated that fillets containing n − 3 HUFA and CLA were essentially without fishy off-flavor and had excellent sensory qualities. Catfish fillets produced by amending diets with sources of n − 3 HUFA and CLA at the levels used in this study would contain elevated levels of these nutraceuticals and could be an important human food source for these healthful fatty acids.     

Lectin‐Binding Pattern in Ovarian Structures of Rats with Experimental Polycystic Ovaries

Numerous experimental models in different species have been developed for the study of polycystic ovarian syndrome. In this study, we used a model of induction of polycystic ovaries (PO) in rats by exposure to constant light to study the distribution and variations of glycosylated residues present in the different ovarian structures. Seven biotinylated lectins were used (Con‐A, WGA, DBA, SBA, PNA, RCA and UEA‐I) on tissue sections, and detection was performed using the streptavidin/peroxidase method. In tissue sections was observed an increase in affinity for Con‐A in the granulosa and theca interna of growing follicles and cysts in animals with PO in relation to the control group. Follicular cysts showed higher affinity for WGA and RCA‐I which growing follicles in the same group, and there was a decrease in affinity for PNA in the cysts in relation to the growth of follicles in both groups. Atretic follicles in both groups showed greater labelling with lectins PNA, SBA and RCA‐I in relation to healthy follicles. It could also be noted that the zona pellucida of cystic follicles lost the affinity for the lectin Con‐A. There was no staining on follicles in any category with the lectins DBA and UEA‐I, although it was staining in the corpus luteum (control group) and in the mesothelium and interstitial glands of both groups with DBA. These observations probably reflect changes in the glycosaminoglycans present in the different ovarian compartments or in the glycosylation of cellular components essential for proper follicular dynamics.     

Liquorice and canine Addison's disease

Abstract

Extract

Hypoadrenocorticism, or Addison's disease, is an uncommon en-docrinopathy of dogs (Feldman and Nelson 2004 Feldman, EC and Nelson, RW. 2004. “Hypoadrenocorticism (Addison's disease)”. In Canine and Feline Endocrinology and Reproduction, 3rd, 394–439. Philadelphia, , USA: WB Saunders.  [Google Scholar]). Long-term management of affected dogs in New Zealand involves treatment with oral fludrocortisone acetate (Florinef tablets; Bristol-Myers Squibb (NZ) Ltd, Auckland, NZ), which is a relatively expensive synthetic adrenocortical steroid. Table salt may be added to the food, in an attempt to reduce the amount of fludrocortisone required. Despite fludrocortisone therapy, many Addisonian dogs remain hyponatraemic and hyperkalaemic and the required dose of fludrocortisone may need to be increased during the first year of treatment. Increasing the dose of fludrocortisone is not only expensive, but may also have undesirable effects through its potent glucocorticoid action.