University of Saskatchewan

About: University of Saskatchewan is a education organization based out in Saskatoon, Saskatchewan, Canada. It is known for research contribution in the topics: Population & Health care. The organization has 25021 authors who have published 52579 publications receiving 1483049 citations. The organization is also known as: USask.

Transcending Cultural Borders: Implications for Science Teaching

Abstract: The current development towards ‘science for all’ in all parts of the globe necessitates that consideration be given to how pupils move between their everyday life‐world and the world of school science, how pupils deal with cognitive conflicts between those two worlds, and what this means for effective teaching of science. This paper reviews a new cognitive explanation‐‐collateral learning theory‐‐for how pupils cope with disparate worldviews mediated by transcending cultural borders between their everyday culture and the culture of science. The assistance that most pupils receive when they attempt to negotiate these cultural borders will influence their success at science. A new pedagogy is proposed in which teachers assume a role of culture broker in the classroom to achieve culturally sensitive curriculum and assessment.

Transport of α-Helical Peptides through α-Hemolysin and Aerolysin Pores†

Abstract: A series of negatively charged α-helical peptides of the general formula fluorenylmethoxycarbonyl (Fmoc)-DxAyKz were synthesized, where x and z were 1, 2, or 3 and y was 10, 14, 18, or 22. The translocation of the peptides through single pores, which were self-assembled into lipid membranes, was analyzed by measuring the current blockade iblock and the duration tblock. The pores were either α-hemolysin, which has a wide vestibule leading into the pore, or aerolysin, which has no vestibule but has a longer pore of a similar diameter. Many thousands of events were measured for each peptide with each pore, and they could be assigned to two types: bumping events (type I) have a small iblock and long tblock, and translocation events (type II) have a larger iblock and shorter tblock. For type-II events, both iblock and tblock increase with the length of the peptides on both pores tested. The dipole moment and the net charge of each peptide has a major effect on the transport characteristics. The ratio of type-...

Aging produces a specific pattern of striatal dopamine loss: implications for the etiology of idiopathic Parkinson's disease.

Abstract: To examine the possible causal contribution of normal or accelerated aging to the neurodegenerative process of Parkinson's disease, we measured the influence of aging on subregional striatal dopamine and homovanillic acid levels in postmortem brain of 23 neurologically and psychiatrically normal human subjects 14-92 years old. We observed a significant decline in striatal dopamine levels and increase in the homovanillic acid/dopamine molar ratios with increasing age. The dopamine loss, on average, was of the same magnitude in the caudate nucleus and the putamen (-60% in the 84-year-old group as compared with the 22-year-old group), with the caudal component of both nuclei being more affected than the rostral subdivisions. The level of subregional dopamine metabolism, as measured by the homovanillic acid/dopamine ratio, in our young individuals (mean age, 22 years) was found to be inversely correlated to the degree of subregional dopamine loss suffered by the individuals in the older age groups. We conclude the following: (a) Striatal subdivisions with physiologically higher dopamine metabolism are not at a greater risk of suffering dopamine neuronal damage with advancing age, as would seem to be implied by the oxidative stress hypothesis; thus, formation of dopamine-derived oxy radicals in the human striatum appears unlikely to be a primary factor responsible for the age-related striatal dopamine loss. (b) The regional and subregional pattern of striatal dopamine loss in normal aging differs substantially from the pattern typically observed in idiopathic Parkinson's disease; therefore, the cause of idiopathic Parkinson's disease cannot be primarily an age-dependent neurodegenerative process.