5,943 research outputs found

    Noncognitive Variables to Predict Academic Success Among Junior Year Baccalaureate Nursing Students

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    An equitable predictor of academic success is needed as nursing education strives toward comprehensive preparation of diverse nursing students. The purpose of this study was to discover how Sedlacek’s (2004a) Noncognitive Questionnaire (NCQ) and Duckworth & Quinn’s (2009) Grit-S predicted baccalaureate nursing student academic performance and persistence in the junior year, when considered in conjunction with academic variables such as previous college GPAs and the SAT. Three cohorts of junior year nursing students (N= 150) answered the survey, and their academic records were combed for previous college GPAs and SAT scores. After the junior academic year, these variables were regressed on junior year student grade point averages and persistence in the major (dependent variables) to determine predictors of academic success among this student group. Findings indicated that previous college GPAs were the most predictive of junior year success. These results impact the practice of nursing education in several ways, and lead to suggestions for further research

    Einselection and Decoherence from an Information Theory Perspective

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    We introduce and investigate a simple model of conditional quantum dynamics. It allows for a discussion of the information-theoretic aspects of quantum measurements, decoherence, and environment-induced superselection (einselection).Comment: Proceedings of the Planck constant centenary meeting. Uses annalen.cls and fleqn.st

    Quantifying Charge Effects on Fouling Layer Strength and (Ir)Removability during Cross-Flow Microfiltration

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    Fouling of membranes is still an important limiting factor in the application of membrane technology. Therefore, there is still a need for an in-depth understanding of which parameters affect the (ir)removability of fouling layers, as well as the mechanisms behind fouling. In this study, fluid dynamic gauging (FDG) was used to investigate the influence of charge effects between negatively charged foulant particles and cations on cake cohesive strength. Fouling cakes’ thicknesses and cohesive strengths were estimated during membrane operations, where microfiltration (MF) membranes were fouled in a feed-and-bleed cross-flow filtration system with low and highly negatively charged polystyrene-polyacrylic acid core-shell particles. In addition, an added procedure to determine the irremovability of cakes using FDG was also proposed. Comparing layers formed in the presence and absence of calcium ions revealed that layers formed without calcium ions had significantly lower cohesive strength than layers formed in the presence of calcium ions, which is explained by the bridging effect between negatively charged particles and calcium ions. Results also confirmed more cohesive cakes formed by high negative charge particles in the presence of calcium compared to lower negative charge particles. Hence, it was demonstrated that FDG can be used to assess the cohesive strength ((ir)removability) of cake layers, and to study how cake cohesive strength depends on foulant surface charge and ionic composition of the solution

    Development of a fluid dynamic gauging method for the characterization of fouling behavior during cross-flow filtration of a wood extraction liquor

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    A method based on fluid dynamic gauging (FDG) was developed to investigate the membrane fouling behavior of streams containing dissolved wood components and small particles extracted using a mild steam explosion pretreatment. Industrially chipped softwood was subjected to saturated steam at 7 bar for 20 min, followed by cross-flow filtration of steam explosion liquors using 10 kDa polysulfone membranes at 2 bar transmembrane pressure. The results showed a severe decline in permeate flux during the initial stages of the cross-flow filtration. The FDG profiles from five filtration experiments revealed that thicker fouling layers were formed during initial fouling on pristine membranes compared to subsequent fouling on non-pristine membranes. The difference in fouling behavior suggests that cake layer formation was dominant during initial fouling, whereas pore blocking was more pronounced during refouling. This study highlights how FDG can be used to gain a better mechanistic understanding of the fouling behavior of extracted wood components

    Fouling characteristics of microcrystalline cellulose during cross-flow microfiltration: Insights from fluid dynamic gauging and molecular dynamics simulations

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    The fouling behaviour of microcrystalline cellulose (MCC) particles on polyethersulfone (PES) membranes was investigated using fluid dynamic gauging (FDG) and molecular dynamics (MD) simulations. Experimental cross-flow microfiltration (MF) of a dilute MCC suspension at 400 mbar transmembrane pressure using 0.45 μm PES membranes revealed an estimated fouling layer thickness of 616 \ub1 5 μm for both fouled and re-fouled membranes at an applied shear stress of 37 \ub1 2 Pa. A decline in pure water flux was observed after each membrane cleaning and flushing procedure, indicating that highly resilient layers were formed close to the membrane surface. A possible explanation for the formation of resilient cellulose layers was obtained through MD simulations of the free energy profiles, which predicted deep energy minima at close interparticle separations of the cellulose–cellulose and cellulose–PES systems. The consequence of this energy minima is that attractive and repulsive forces are in balance at a specific distance between the particles, suggesting high binding energy at close interparticle distances. This implies that a certain force is needed to remove the layer or redisperse the cellulose particles. MD simulations also suggested that contributions made by repulsive hydration forces negatively influenced the adsorption of cellulose particles onto the PES membrane. These results highlight how experimental FDG measurements, when complemented with MD simulations, can provide insights into the fouling behaviour of an organic model material during cross-flow filtration

    Electroosmotic dewatering of cellulose nanocrystals

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    One of the main challenges for industrial production of cellulose nanocrystals is the high energy demand during the dewatering of dilute aqueous suspensions. It is addressed in this study by utilising electroosmotic dewatering to increase the solid content of suspensions of cellulose nanocrystals. The solid content was increased from 2.3 up to 15.3\ua0wt%, i.e. removal of more than 85% of all the water present in the system, at a much lower energy demand than that of thermal drying. Increasing the strength of the electric field increased not only the dewatering rate but also the specific energy demand of the dewatering operation: the electric field strength used in potential industrial applications is thus a trade-off between the rate of dewatering and the energy demand. Additionally, it was fo und that high local current intensity had the potential of degrading cellulose nanocrystals in contact with the anode. The maximum strength of the electric field applied should therefore be limited depending on the equipment design and the suspension conditions

    p63 is an alternative p53 repressor in melanoma that confers chemoresistance and a poor prognosis.

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    The role of apoptosis in melanoma pathogenesis and chemoresistance is poorly characterized. Mutations in TP53 occur infrequently, yet the TP53 apoptotic pathway is often abrogated. This may result from alterations in TP53 family members, including the TP53 homologue TP63. Here we demonstrate that TP63 has an antiapoptotic role in melanoma and is responsible for mediating chemoresistance. Although p63 was not expressed in primary melanocytes, up-regulation of p63 mRNA and protein was observed in melanoma cell lines and clinical samples, providing the first evidence of significant p63 expression in this lineage. Upon genotoxic stress, endogenous p63 isoforms were stabilized in both nuclear and mitochondrial subcellular compartments. Our data provide evidence of a physiological interaction between p63 with p53 whereby translocation of p63 to the mitochondria occurred through a codependent process with p53, whereas accumulation of p53 in the nucleus was prevented by p63. Using RNA interference technology, both isoforms of p63 (TA and ΔNp63) were demonstrated to confer chemoresistance, revealing a novel oncogenic role for p63 in melanoma cells. Furthermore, expression of p63 in both primary and metastatic melanoma clinical samples significantly correlated with melanoma-specific deaths in these patients. Ultimately, these observations provide a possible explanation for abrogation of the p53-mediated apoptotic pathway in melanoma, implicating novel approaches aimed at sensitizing melanoma to therapeutic agents
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