614 research outputs found
Alteration of intramembrane particle distribution in amphibian urinary bladders exposed to 3,3'-diallyldiethylsilbestrol (DADES)
No full textMELTING from an ISOTHERMAL VERTICAL WALL. Synthesis of a numerical comparison exercise
No full textB. BASU, R. PARDESHI and A.K. SINGH : [email protected]. BERTRAND, E. ARQUIS : [email protected]. BINET : [email protected]. COMBEAU : [email protected]. GOBIN, G. VIEIRA : [email protected]. GOSCIK : [email protected]. LACROIX : [email protected]. LE QUERE : [email protected]. MEDALE : [email protected]. MENCINGER, B. SARLER : [email protected]. SADAT, S. COUTURIER : [email protected]. WINTRUFF : [email protected] audienceThis paper provides an analysis of the results of a comparison exercise on the numerical 2D solution of melting from a vertical wall, dominated by natural convection in the liquid phase. The thirteen contributions to this exercise cover the great variety of mathematical models and numerical procedures most commonly used in this field. The main conclusions presented at the AMIF Workshop (PCC99) held in Warsaw in June 1999 and at the Moving BoundariesSeminar in Ljubljana are summarized in the paper. They emphasize the need for the definition of such reference validation tests
Water pathways across a reconstituted epithelial barrier formed by Caco-2 cells: effect of medium hypertonicity
No full textCaco-2 cells, originated in a human colonic cancer, are currently used as model systems to study transepithelial transports. To further characterize their water permeability properties, clone P1 Caco-2 cells were cultured on permeable supports. At confluence, the transepithelial net water movement (Jw), mannitol permeability (Ps), and electrical resistance (R) were simultaneously measured. The observed results were correlated with transmission and freeze-fracture electron microscopy studies and compared with those obtained, in similar experimental conditions, in a typical mammalian epithelial barrier: the rabbit rectum. When the serosal solution was made hypertonic (50 mM polyethylene glycol-PEG), the spontaneously observed secretory Jw rapidly reversed, became absorptive and then stabilized. Simultaneously, the R values dropped and Ps went up. In the case of the rabbit rectal epithelium, a similar treatment did not elicit significant changes in the water permeability during the first 20 min following the osmotic challenge while there was a significant increase in the transepithelial resistance. After exposure to serosal hypertonicity, several morphological modifications developed in the Caco-2 cells: Localized dilations in the intercellular spaces and vacuoles in the cytoplasm appeared. Nevertheless, most cells remained in contact and no evidence of cell shrinking was observed. Simultaneously, the tight-junction structure was more or less disorganized. The filament network lost its sharpness and "omega" figures appeared, bordering the intercellular spaces. In some cases the tight-junction network was completely disrupted. In the case of the rabbit rectum the structural modifications were completely different: Serosal hypertonicity rapidly induced cell shrinking and the opening of the intercellular spaces, with no noticeable change in the tight-junction structure
Multiculturalisme et marginalisation à Los Angeles. De Watts (1965) à South Central (1992)
No full textMulticulturalism and marginalization in Los Angeles. From Watts (1965) to South Central (1992), Cynthia Ghorra-Godin.
From the 1992 South Central events, the author looks on the major upheavals that have marked Los Angeles in the last two decades: the shifts in population composition since the spectacular arrival of the Hispanics, the socio-economic and inter-ethnic tensions stemming from de-industralization, the limits of political regulation. The sudden riots of 1992, just as the permanent tensions underlying urban life, reflect mainly the failure of a town planning which focused on spatial expansion and individual housing to the detriment of the development of a genuinely public space able to blend the various communities.Ghorra-Gobin Cynthia. Multiculturalisme et marginalisation à Los Angeles. De Watts (1965) à South Central (1992). In: Vingtième Siècle, revue d'histoire, n°40, octobre-décembre 1993. pp. 23-32
Antidiuretic response in the urinary bladder of Xenopus laevis: persistance of typical aggrephores and apical aggregates
No full textThe urinary bladder of the aquatic toad Xenopus laevis is known to exhibit a low permeability to water and a poor sensitivity to antidiuretic hormone. In order to precise the characteristics and the specific cellular mechanisms of this reduced hydro-osmotic response we used a sensitive volumetric technique to monitor net water flow and studied the correlation between the antidiuretic hormone (ADH)-induced net water flow and the fine ultrastructural appearance of the urinary bladder epithelium. Transmural net water flow was entirely dependent on the osmotic gradient across the preparation and not on the hydrostatic pressure difference. We observed the existence of a low but significant hydro-osmotic response to arginine vasopressin. Freeze-fracture electron microscopy demonstrated the presence of typical aggrephores in the subapical cytoplasm. The response to the hormone was accompanied by the appearance of typical intramembrane aggregates into the apical plasma membrane. Water permeability increase and apical aggregate insertion were both slowly but fully reversible. Except for the multilayered structure of the epithelium and the particularly low response to antidiuretic hormone, all the studied permeability and ultrastructural characteristics of the bladder were thus very similar to those observed in other sensitive epithelia such as the amphibian bladder and skin and the mammalian collecting duct which exhibit a high hydro-osmotic response to the hormone
Effects of salt acclimation on water and urea permeabilities across the frog bladder: relationship with intramembrane particle aggregates.
No full textIn salt-acclimated frogs, water and urea bladder permeabilities are markedly higher than in tap water-acclimated animals. 2. Intra-membrane particle aggregates (IMPA) cover an unusually large surface area of the salt-acclimated frog bladder apical plasma membrane. 3. In saline-adapted animals, proteins extracted from the apical plasma membrane contain additional species of 19, 26, 31 and 53-61 kDa. These proteins might be related to the water channels contained by IMPA
Antidiuretic challenge in the urinary bladder of Xenopus laevis: aggrephores and apical particle aggregates
No full textImpact of heat and drought stress on arable crop production in Belgium
No full textModelling approaches are needed to accelerate understanding of adverse weather impacts on crop performances and yields. The aim was to elicit biometeorological conditions that affect Belgian arable crop yield, commensurate with the scale of climatic impacts. The regional crop model REGCROP (Gobin, 2010) enabled to examine changing weather patterns in relation to the crop season and crop sensitive stages of six arable crops: winter wheat, winter barley, winter rapeseed, potato, sugar beet and maize. The sum of vapour pressure deficit during the growing season is the single best predictor of arable yields, with <i>R</i><sup>2</sup> ranging from 0.55 for sugar beet to 0.76 for wheat. Drought and heat stress, in particular during the sensitive crop stages, occur at different times in the crop season and significantly differ between two climatic periods, 1947–1987 and 1988–2008. Though average yields have risen steadily between 1947 and 2008, there is no evidence that relative tolerance to stress has improved
Opening Plenary
No full textWelcome from Conference Organizers Scott Redman, Executive Chair Cecilia Gobin, Program Co-Chair Julie Watson, Program Co-Chair Fran Wilshusen, Program Co-Chair Christianne Wilhelmson, Program Co-Chair Ginny Broadhurst, Salish Sea Institute Coast Salish Welcome Cecilia Gobin, Northwest Indian Fisheries Commission Coast Salish Perspectives on the Last 150 years Patti Gobin, Tulalip Tribes Patti Gobin has over 25 years of Community Development experience with the Tulalip Tribes. Presently, she is with the Natural Resource Treaty Rights office working with state, local and federal agencies regarding those issues that impact the life ways of the Tulalip Tribes. In addition to her years of experience, Ms. Gobin is a member of the Tulalip Tribes and is well versed in the culture and history of her people. Her personal goal is to invest in the future of the Coast Salish community, helping to affect a sustainable future for the next generations to come. The State of the Salish Sea Dr Isobel Pearsall and Dr Kathryn Sobocinski will give an overview about the current state of the Salish Sea. Both have led recent Salish Sea ecosystem-wide analyses – the Salish Sea Marine Survival Project and the State of the Salish Sea report, respectively. Isobel and Kathryn will each provide presentations followed by discussion with the session moderators Scott Redman, Science Program Director at the Puget Sound Partnership and Christianne Wilhelmson, Executive Director of Georgia Strait Alliance. Dr. Isobel Pearsall is the Director of the Pacific Salmon Foundation’s Marine Science Program. She co-ordinated the Canadian component of the international Salish Sea Marine Survival Project, a $24M program set to address declines in Chinook, Coho and Steelhead in the Salish Sea (2014-2019) and is continuing to work on this massive transboundary effort. Isobel holds a first class degree in Pure and Applied biology from Oxford University, a M.Sc. in Ecology from the Department of Biology at Dalhousie University, and a PhD. in Ecology from the Department of Plant Science, UBC. She was a post-doctoral fellow in ecosystem management at the Pacific Biological Station, Department of Fisheries and Oceans, Nanaimo. Since 1995, she has worked as a scientist on numerous programs for government, non-profit organizations, and private industry. She is an adjunct professor at UBC. Dr. Kathryn L. Sobocinski is an Assistant Professor in the Department of Environmental Sciences and the Marine and Coastal Science program at Western Washington University. She is the lead author of State of the Salish Sea published May 2021. Kathryn is an applied marine ecologist focusing on fishes, fish habitats, and impacts of human disturbance and climate change in coastal ecosystems. She holds a BA in Environmental Studies from Connecticut College, MS in Aquatic and Fishery Sciences from the University of Washington, and PhD in Marine Science from the Virginia Institute of Marine Science/College of William & Mary. Kathryn completed post-doctoral work at Oregon State University and NOAA-NWFSC prior to joining the WWU faculty. She resides in Bellingham, WA
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