University of Rochester

About: University of Rochester is a education organization based out in Rochester, New York, United States. It is known for research contribution in the topics: Population & Laser. The organization has 63915 authors who have published 112762 publications receiving 5484122 citations. The organization is also known as: Rochester University.

Expression of Pseudomonas aeruginosa virulence genes requires cell-to-cell communication

Abstract: Pseudomonas aeruginosa is an opportunistic human pathogen that causes a variety of infections in immunocompromised hosts and individuals with cystic fibrosis. Expression of elastase, one of the virulence factors produced by this organism, requires the transcriptional activator LasR. Experiments with gene fusions show that gene lasl is essential for high expression of elastase. The lasl gene is involved in the synthesis of a diffusible molecule termed Pseudomonas autoinducer (PAI). PAI provides P. aeruginosa with a means of cell-to-cell communication that is required for the expression of virulence genes and may provide a target for therapeutic approaches.

Impairment of paravascular clearance pathways in the aging brain

Abstract: Objective: In the brain, protein waste removal is partly performed by paravascular pathways that facilitate convective exchange of water and soluble contents between cerebrospinal fluid (CSF) and interstitial fluid (ISF). Several lines of evidence suggest that bulk flow drainage via the glymphatic system is driven by cerebrovascular pulsation, and is dependent on astroglial water channels that line paravascular CSF pathways. The objective of this study was to evaluate whether the efficiency of CSF–ISF exchange and interstitial solute clearance is impaired in the aging brain. Methods: CSF–ISF exchange was evaluated by in vivo and ex vivo fluorescence microscopy and interstitial solute clearance was evaluated by radiotracer clearance assays in young (2–3 months), middle-aged (10–12 months), and old (18–20 months) wild-type mice. The relationship between age-related changes in the expression of the astrocytic water channel aquaporin-4 (AQP4) and changes in glymphatic pathway function was evaluated by immunofluorescence. Results: Advancing age was associated with a dramatic decline in the efficiency of exchange between the subarachnoid CSF and the brain parenchyma. Relative to the young, clearance of intraparenchymally injected amyloid-b was impaired by 40% in the old mice. A 27% reduction in the vessel wall pulsatility of intracortical arterioles and widespread loss of perivascular AQP4 polarization along the penetrating arteries accompanied the decline in CSF–ISF exchange. Interpretation: We propose that impaired glymphatic clearance contributes to cognitive decline among the elderly and may represent a novel therapeutic target for the treatment of neurodegenerative diseases associated with accumulation of misfolded protein aggregates. ANN NEUROL 2014;76:845–861

Self-Assembly of Ordered Microporous Materials from Rod-Coil Block Copolymers

Abstract: Rod-coil diblock copolymers in a selective solvent for the coil-like polymer self-organize into hollow spherical micelles having diameters of a few micrometers. Long-range, close-packed self-ordering of the micelles produced highly iridescent periodic microporous materials. Solution-cast micellar films consisted of multilayers of hexagonally ordered arrays of spherical holes whose diameter, periodicity, and wall thickness depended on copolymer molecular weight and composition. Addition of fullerenes into the copolymer solutions also regulated the microstructure and optical properties of the microporous films. These results demonstrate the potential of hierarchical self-assembly of macromolecular components for engineering complex two- and three-dimensional periodic and functional mesostructures.

Four channels mediate the mechanical aspects of touch

Abstract: Although previous physiological and anatomical experiments have identified four afferent fiber types (PC, RA, SA II, and SA I) in glabrous (nonhairy) skin of the human somatosensory periphery, only three have been shown to mediate tactile (mechanoreceptive) sensation. Psychophysical evidence that four channels (P, NP I, NP II, and NP III) do, indeed, participate in the perceptual process is presented. In a series of experiments involving selective masking of the various channels, modification of the skin‐surface temperature, and testing cutaneous sensitivity down to very low‐vibratory frequencies, the fourth psychophysical channel (NP III) is defined. Based on these experiments and previous work from our laboratory, it is concluded that the four channels work in conjunction at threshold to create an operating range for the perception of vibration that extends from at least 0.4 to greater than 500 Hz. Each of the four channels appears to mediate specific portions of the overall threshold‐frequency characteristic. Selection of appropriate neural‐response criteria from previously published physiological data and correlation of their derived frequency characteristics with the four psychophysical channels indicates that each channel has its own physiological substrate: P channel and PC fibers, NP I channel and RA fibers, NP II channel and SA II fibers, and NP III channel and SA I fibers. These channels partially overlap in their absolute sensitivities, making it likely that suprathreshold stimuli may activate two or more of the channels at the same time. Thus the perceptual qualities of touch may be determined by the combined inputs from four channels.

Predicting Success in College: A Longitudinal Study of Achievement Goals and Ability Measures as Predictors of Interest and Performance From Freshman Year Through Graduation

Abstract: The authors examined the role of achievement goals, ability, and high school performance in predicting academic success over students’ college careers. First, the authors examined which variables predicted students’ interest and performance in an introductory psychology course taken their first semester in college. Then, the authors followed students until they graduated to examine continued interest in psychology and performance in subsequent classes. Achievement goals, ability measures, and prior high school performance each contributed unique variance in predicting initial and long-term outcomes, but these predictors were linked to different educational outcomes. Mastery goals predicted continued interest, whereas performance-approach goals predicted performance. Ability measures and prior high school performance predicted academic performance but not interest. The findings support a multiple goals perspective.