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.

Pre-treatment of flax fibers for use in rotationally molded biocomposites

Abstract: The objective of this study was to determine the effects of pre-treated flax fibers on the performance of the fiber-reinforced composites. Lack of good interfacial adhesion and poor resistance to moisture absorption make the use of natural fiber-reinforced composites less attractive. In order to improve fiber/matrix interfacial properties, fibers were subjected to chemical treatments, namely, mercerization, silane treatment, benzoylation, and peroxide treatment. Selective removal of non-cellulosic compounds constitutes the main objective of the chemical treatments of flax fibers to improve the performance of fiber-reinforced composites. Flax fibers were derived from Saskatchewan-grown flax straws. Composites consisting of high-density polyethylene (HDPE) or linear low-density polyethylene (LLDPE) or HDPE/LLDPE mix, chemically treated fibers and additives were prepared by the extrusion process. The test samples were prepared by rotational molding. The fiber surface morphology and the tensile fracture surfa...

Transformation of two-line ferrihydrite to goethite and hematite as a function of pH and temperature.

Abstract: Under oxic aqueous conditions, two-line ferrihydrite gradually transforms to more thermodynamically stable and more crystalline phases, such as goethite and hematite. This temperature- and pH-dependent transformation can play an important role in the sequestration of metals and metalloids adsorbed onto ferrihydrite. A comprehensive assessment of the crystallization of two-line ferrihydrite with respect to temperature (25, 50, 75, and 100 °C) and pH (2, 7, and 10) as a function of reaction time (minutes to months) was conducted via batch experiments. Pure and transformed phases were characterized by X-ray diffraction (XRD), X-ray absorption near-edge spectroscopy (XANES), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The rate of transformation of two-line ferrihydrite to hematite increased with increasing temperature at all pHs studied and followed first-order reaction kinetics. XRD and XANES showed simultaneous formation of goethite and hematite at 50 and 75 °C at pH 10, with hema...

Pulmonary oedema associated with airway obstruction.

Abstract: The purpose of this review is to describe the pathogenesis of pulmonary oedema associated with upper airway obstruction, summarize what is known of its clinical presentation, and reflect upon its implications for the clinical management of airway obstruction. The pathogenesis of pulmonary oedema associated with upper airway obstruction is multifactorial. However, as the phrase "negative pressure pulmonary oedema" suggests, markedly negative intrapleural pressure is the dominant pathophysiological mechanism involved in the genesis of pulmonary oedema associated with upper airway obstruction. The frequency of the event is impossible to ascertain from the literature but paediatric cases requiring airway intervention for croup or epiglottitis and adults requiring airway intervention for emergence laryngospasm or upper airway tumours account for over 50 per cent of the documented cases in each age group, respectively. Individuals at risk should be observed closely while they remain at risk. The majority of cases present within minutes either of the development of acute severe upper airway obstruction or of relief of the obstruction. Resolution is typically rapid, over a period of a few hours. Rarely is anything more required for management than the maintenance of a patent airway, supplemental oxygen, and, in approximately 50 per cent of cases, mechanical ventilation and positive end-expiratory pressure.

Plants Integrate Information About Nutrients and Neighbors

Abstract: Animals regularly integrate information about the location of resources and the presence of competitors, altering their foraging behavior accordingly. We studied the annual plant Abutilon theophrasti to determine whether a plant can demonstrate a similarly complex response to two conditions: presence of a competitor and heterogeneous resource distributions. Individually grown plants fully explored the pot by using a broad and uniform rooting distribution regardless of soil resource distributions. Plants with competitors and uniform soil nutrient distributions exhibited pronounced reductions in rooting breadth and spatial soil segregation among the competing individuals. In contrast, plants with competitors and heterogeneous soil nutrient distributions reduced their root growth only modestly, indicating that plants integrate information about both neighbor and resource distributions in determining their root behavior.