Digital control of magnetic bearings supporting a multimass flexible rotor

The characteristics of magnetic bearings used to support a three mass flexible rotor operated at speeds up to 14,000 RPM are discussed. The magnetic components of the bearing are of a type reported in the literature previously, but the earlier analog controls were replaced by digital ones. Analog-to-digital and digital-to-analog converters and digital control software were installed in an AT&T PC. This PC-based digital controller was used to operate one of the magnetic bearings on the test rig. Basic proportional-derivative control was applied to the bearings, and the bearing stiffness and damping characteristics were evaluated. Particular attention is paid to the frequency dependent behavior of the stiffness and damping properties, and comparisons are made between the actual controllers and ideal proportional-derivative control

ISS Solar Array Management

The International Space Station (ISS) Solar Array Management (SAM) software toolset provides the capabilities necessary to operate a spacecraft with complex solar array constraints. It monitors spacecraft telemetry and provides interpretations of solar array constraint data in an intuitive manner. The toolset provides extensive situational awareness to ensure mission success by analyzing power generation needs, array motion constraints, and structural loading situations. The software suite consists of several components including samCS (constraint set selector), samShadyTimers (array shadowing timers), samWin (visualization GUI), samLock (array motion constraint computation), and samJet (attitude control system configuration selector). It provides high availability and uptime for extended and continuous mission support. It is able to support two-degrees-of-freedom (DOF) array positioning and supports up to ten simultaneous constraints with intuitive 1D and 2D decision support visualizations of constraint data. Display synchronization is enabled across a networked control center and multiple methods for constraint data interpolation are supported. Use of this software toolset increases flight safety, reduces mission support effort, optimizes solar array operation for achieving mission goals, and has run for weeks at a time without issues. The SAM toolset is currently used in ISS real-time mission operations

Eye movements during information processing tasks: Individual differences and cultural effects

AbstractThe eye movements of native English speakers, native Chinese speakers, and bilingual Chinese/English speakers who were either born in China (and moved to the US at an early age) or in the US were recorded during six tasks: (1) reading, (2) face processing, (3) scene perception, (4) visual search, (5) counting Chinese characters in a passage of text, and (6) visual search for Chinese characters. Across the different groups, there was a strong tendency for consistency in eye movement behavior; if fixation durations of a given viewer were long on one task, they tended to be long on other tasks (and the same tended to be true for saccade size). Some tasks, notably reading, did not conform to this pattern. Furthermore, experience with a given writing system had a large impact on fixation durations and saccade lengths. With respect to cultural differences, there was little evidence that Chinese participants spent more time looking at the background information (and, conversely less time looking at the foreground information) than the American participants. Also, Chinese participants’ fixations were more numerous and of shorter duration than those of their American counterparts while viewing faces and scenes, and counting Chinese characters in text

A State-Wide Union Catalog Feasibility Study: Final Report on Project III-D FY 1976

Coordinated Science Laboratory was formerly known as Control Systems Laborator

Biofilms: possible strategies for suppression in chronic wounds

The aim of this paper is to provide a brief overview of strategies that could be applied to chronic wounds harbouring biofilms. The importance of biofilms in chronic wounds is highlighted in respect of them preventing the normal wound healing processes and with regards to their resistance to removal by conventional antimicrobial agents. An array of anti-biofilm agents is provided, and the mode of action of these agents together with their efficacy in suppressing biofilms is discussed. It is hoped this article will provide foresight into wound management and promote consideration of future anti-biofilm strategies

Antimicrobial resistance in equine faecal Escherichia coli isolates from North West England

<p>Abstract</p> <p>Background</p> <p><it>Escherichia coli </it>isolates of equine faecal origin were investigated for antibiotic resistance, resistance genes and their ability to perform horizontal transfer.</p> <p>Methods</p> <p>In total, 264 faecal samples were collected from 138 horses in hospital and community livery premises in northwest England, yielding 296 resistant <it>E. coli </it>isolates. Isolates were tested for susceptibility to antimicrobial drugs by disc diffusion and agar dilution methods in order to determine minimum inhibitory concentrations (MIC). PCR amplification was used to detect genes conferring resistance to: ampicillin (TEM and SHV beta-lactamase), chloramphenicol (<it>catI, catII, catIII </it>and <it>cml</it>), tetracycline <it>(tetA, tetB, tetC, tetD, tet E </it>and <it>tetG</it>), and trimethoprim (<it>dfrA1, dfrA9, dfrA12, dfrA13, dfr7</it>, and <it>dfr17</it>).</p> <p>Results</p> <p>The proportion of antibiotic resistant isolates, and multidrug resistant isolates (MDR) was significantly higher in hospital samples compared to livery samples (MDR: 48% of hospital isolates; 12% of livery isolates, p < 0.001). Resistance to ciprofloxacin and florfenicol were identified mostly within the MDR phenotypes. Resistance genes included <it>dfr</it>, TEM beta-lactamase, <it>tet </it>and <it>cat</it>, conferring resistance to trimethoprim, ampicillin, tetracycline and chloramphenicol, respectively. Within each antimicrobial resistance group, these genes occurred at frequencies of 93% (260/279), 91%, 86.8% and 73.5%, respectively; with 115/296 (38.8%) found to be MDR isolates. Conjugation experiments were performed on selected isolates and MDR phenotypes were readily transferred.</p> <p>Conclusions</p> <p>Our findings demonstrate that <it>E. coli </it>of equine faecal origin are commonly resistant to antibiotics used in human and veterinary medicine. Furthermore, our results suggest that most antibiotic resistance observed in equine <it>E. coli </it>is encoded by well-known and well-characterized resistant genes common to <it>E. coli </it>from man and domestic animals. These data support the ongoing concern about antimicrobial resistance, MDR, antimicrobial use in veterinary medicine and the zoonotic risk that horses could potentially pose to public health.</p

Engineered Skeletal Muscle Units for Repair of Volumetric Muscle Loss in the Tibialis Anterior Muscle of a Rat

Volumetric muscle loss (VML) is the traumatic, degenerative, or surgical loss of muscle tissue, which may result in function loss and physical deformity. To date, clinical treatments for VML?the reflected muscle flap or transferred muscle graft?are limited by tissue availability and donor site morbidity. To address the need for more innovative skeletal muscle repair options, our laboratory has developed scaffoldless tissue-engineered skeletal muscle units (SMUs), multiphasic tissue constructs composed of engineered skeletal muscle with engineered bone-tendon ends, myotendinous junctions, and entheses, which in vitro can produce force both spontaneously and in response to electrical stimulation. Though phenotypically immature in vitro, we have shown that following 1 week of implantation in an ectopic site, our muscle constructs develop vascularization and innervation, an epimysium-like outer layer of connective tissue, an increase in myosin protein content, formation of myofibers, and increased force production. These findings suggest that our engineered muscle tissue survives implantation and develops the interfaces necessary to advance the phenotype toward adult muscle. The purpose of this study was to evaluate the potential of our SMUs to restore muscle tissue to sites of acute VML. Our results indicate that our SMUs continue to mature in vivo with longer recovery times and have the potential to repair VML sites by providing additional muscle fibers to damaged muscles. We conclude from this study that our SMUs have the potential to restore lost tissue volume in cases of acute VML.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140233/1/ten.tea.2014.0060.pd

Gamma band activity in the developing parafascicular nucleus

The parafascicular nucleus (Pf) receives cholinergic input from the pedunculopontine nucleus, part of the reticular activating system involved in waking and rapid eye movement (REM) sleep, and sends projections to the cortex. We tested the hypothesis that Pf neurons fire maximally at gamma band frequency (30–90 Hz), that this mechanism involves high-threshold voltage-dependent P/Q- and N-type calcium channels, and that this activity is enhanced by the cholinergic agonist carbachol (CAR). Patch-clamped 9- to 25-day-old rat Pf neurons (n = 299) manifested a firing frequency plateau at gamma band when maximally activated (31.5 ± 1.5 Hz) and showed gamma oscillations when voltage-clamped at holding potentials above −20 mV, and the frequency of the oscillations increased significantly with age (24.6 ± 3.8 vs. 51.6 ± 4.4 Hz, P < 0.001) but plateaued at gamma frequencies. Cells exposed to CAR showed significantly higher frequencies early in development compared with those without CAR (24.6 ± 3.8 vs. 41.7 ± 4.3 Hz, P < 0.001) but plateaued with age. The P/Q-type calcium channel blocker ω-agatoxin-IVA (ω-Aga) blocked gamma oscillations, whereas the N-type blocker ω-conotoxin-GVIA (ω-CgTx) only partially decreased the power spectrum amplitude of gamma oscillations. The blocking effect of ω-Aga on P/Q-type currents and ω-CgTx on N-type currents was consistent over age. We conclude that P/Q- and N-type calcium channels appear to mediate Pf gamma oscillations during development. We hypothesize that the cholinergic input to the Pf could activate these cells to oscillate at gamma frequency, and perhaps relay these rhythms to cortical areas, thus providing a stable high-frequency state for “nonspecific” thalamocortical processing.Fil: Kezunovic, Nebojsa. University Of Arkansas For Medical Sciences; Estados UnidosFil: Hyde, James. University Of Arkansas For Medical Sciences; Estados UnidosFil: Simon, Christen. University Of Arkansas For Medical Sciences; Estados UnidosFil: Urbano Suarez, Francisco Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Williams, D. Keith. University Of Arkansas For Medical Sciences; Estados UnidosFil: Garcia Rill, Edgar. University Of Arkansas For Medical Sciences; Estados Unido