14 research outputs found

    Evaluation of a Silica Hydride Based Diol Stationary Phase For High Pressue Liquid Chromatogrphy

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    The impact of chromatography across many scientific fields and applications is limitless. It is a vital everyday separation, characterization, and purification tool for many scientists worldwide. Innovations in high performance liquid chromatography (HPLC) stationary phases have led to more diverse separations essential to many fields including the pharmaceutical industry and research. Silica hydride based stationary phases have been shown to display both reverse phase (RP) and aqueous normal phase (ANP) chromatographic behavior. This is a result of both the silica hydride surface and the bonded phase. The goal of this work was to characterize silica hydride based diol stationary phases for HPLC. A wide range of compounds with varying polarities were analyzed. Retention was observed under ANP and RP conditions. Two representative silica hydride based diol stationary phases were compared to demonstrate the effect that the length of the bonded phase has on the separation capabilities of the column. The diol bonded phase with a longer carbon chain retained analytes with more hydrophobic (or non-polar) characteristics longer than analytes with more hydrophilic properties. As part of a larger study the effect of buffer concentration on the ANP retention of model compounds was investigated. Retention dramatically decreased when the concentration of some buffers was increased. This trend is opposite of what has been observed in hydrophilic interaction liquid chromatography (HILLIC), indicating a clear distinction in the retention mecahism for HILLIC and ANP

    The Irvine, Beatties, and Bresnahan (IBB) Forelimb Recovery Scale: An Assessment of Reliability and Validity

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    The IBB scale is a recently developed forelimb scale for the assessment of fine control of the forelimb and digits after cervical spinal cord injury (SCI; Irvine et al., 2010). The present paper describes the assessment of inter-rater reliability and face, concurrent and construct validity of this scale following SCI. It demonstrates that the IBB is a reliable and valid scale that is sensitive to severity of SCI and to recovery over time. In addition, the IBB correlates with other outcome measures and is highly predictive of biological measures of tissue pathology. Multivariate analysis using principal component analysis (PCA) demonstrates that the IBB is highly predictive of the syndromic outcome after SCI (Ferguson et al., 2013), and is among the best predictors of bio-behavioral function, based on strong construct validity. Altogether, the data suggest that the IBB, especially in concert with other measures, is a reliable and valid tool for assessing neurological deficits in fine motor control of the distal forelimb, and represents a powerful addition to multivariate outcome batteries aimed at documenting recovery of function after cervical SCI in rats
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