4,610 research outputs found

    Silicon Waveguides and Ring Resonators at 5.5 {\mu}m

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    We demonstrate low loss ridge waveguides and the first ring resonators for the mid-infrared, for wavelengths ranging from 5.4 to 5.6 {\mu}m. Structures were fabricated using electron-beam lithography on the silicon-on-sapphire material system. Waveguide losses of 4.0 +/- 0.7 dB/cm are achieved, as well as Q-values of 3.0 k.Comment: 4 pages, 4 figures, includes supplemental material

    Self-regulation: A new perspective on learning problems experienced by children born extremely preterm

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    Survival rates are increasing for children born extremely preterm, yet despite the majority of these children having IQ scores within the average range, 50-70% of these children have later school difficulties. This paper reviews factors associated with academic difficulties in these children, emphasizing the contributions of executive functions (EF) and self-regulation. The roles of EF are examined separately, and also under the unifying construct of self-regulation; that is, the integration of various behavioural, cognitive, and affective elements. Improving self-regulatory skills could moderate the negative effects of EF deficits and inform interventions to improve the educational outcomes of these childre

    Structure of a liquid crystalline fluid around a macroparticle: Density functional theory study

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    The structure of a molecular liquid, in both the nematic liquid crystalline and isotropic phases, around a cylindrical macroparticle, is studied using density functional theory. In the nematic phase the structure of the fluid is highly anisotropic with respect to the director, in agreement with results from simulation and phenomenological theories. On going into the isotropic phase the structure becomes rotationally invariant around the macroparticle with an oriented layer at the surface.Comment: 10 pages, 6 figues. Submitted to Phys. Rev.

    Identification of Plasma Cells in Lung Alveoli and Interstitial Tissues After Localized Lung Immunization

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    Large numbers of antibody‐forming cells (AFC) can be identified with the Jerne plaque assay in immunized lung lobes of the beagle dog after localized instillation of particulate antigen. Published data suggest that these AFC are secreting antibody and are responsible for increased levels of specific antibody in immunized lung lobes. If AFC in the lung are actively secreting antibody, there should be an increase in the number of mature plasma cells in lung lobes exposed to antigen. The purposes of this study were to evaluate the number of lymphoid cells present in immunized and control lung lobes and to determine if lung immunization produces a localized increase in the number of plasma cells. Sheep red blood cells (SRBC), autologous dog red blood cells, and saline were instilled into specific lung lobes of beagle dogs with the aid of a fiberoptic bronchoscope. Light and transmission electron microscopy studies of tissues from lung lobes instilled with SRBC showed perivascular infiltrates and intra‐alveolar accumulations of lymphoid cells which were not present in control lung lobes. The morphology of these lymphoid cells ranged from small lymphocytes through mature plasma cells. From 5% to 15% of the cells present in the interstitial tissues and alveoli of immunized lung lobes were plasma cells. These observations suggest that lymphoid cells which entered the SRBC immunized lung can mature to plasma cells which are probably responsible for the local production of antigen‐specific antibody.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142186/1/jlb0001.pd

    Force Output Comparison between Six U.S. Collegiate Athletic Teams.

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    The aim of the study was to compare allometrically scaled peak force and the force at 250 ms between six U.S. collegiate sport teams using isometric mid-thigh pull. Ninety subjects performed maximum effort of isometric mid-thigh pull to measure force output. The data were averaged within the teams, and statistically compared between teams using one-way ANOVA (p=.01). Significant difference was found that men’s soccer and baseball produced higher allometrically scaled peak force, and men’s soccer, tennis, and baseball produced higher allometrically scaled force at 250 ms. The data indicates that not all sports possess similar strength characteristics because of the nature of the sports, and observed separation between gender. Teams such as volleyball and baseball showed higher coefficient of variation due to the various positions within their sports

    Protein−Surfactant Film Voltammetry of Wild-Type and Mutant Cytochrome P450 BM3

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    We are investigating the redox chemistry of wild-type (WT) and mutant (1-12G) cytochrome P450 BM3. Absorption spectra in solution feature the FeIII Soret at 418 nm for WT and a split Soret for 1-12G at 390 and 418 nm. Voltammetry of the proteins within DDAPSS films on the surface of carbon electrodes reveal nearly identical Fe^(III/II) potentials (approximately −200 mV vs Ag/AgCl), but significant differences in k°, 250 vs 30 s^(-1), and Fe^(III/II)−CO potentials, −140 vs −115 mV, for WT vs 1-12G. Catalytic reduction of dioxygen by the proteins on rotating-disk electrodes was analyzed using Levich and Koutecky−Levich treatments. The data reveal 1-12G n and k_(obs) values that are, respectively, 1.7 and 0.07 times those of WT, suggesting that the two proteins differ strikingly in their reactions with dioxygen

    Hysteresis phenomenon in deterministic traffic flows

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    We study phase transitions of a system of particles on the one-dimensional integer lattice moving with constant acceleration, with a collision law respecting slower particles. This simple deterministic ``particle-hopping'' traffic flow model being a straightforward generalization to the well known Nagel-Schreckenberg model covers also a more recent slow-to-start model as a special case. The model has two distinct ergodic (unmixed) phases with two critical values. When traffic density is below the lowest critical value, the steady state of the model corresponds to the ``free-flowing'' (or ``gaseous'') phase. When the density exceeds the second critical value the model produces large, persistent, well-defined traffic jams, which correspond to the ``jammed'' (or ``liquid'') phase. Between the two critical values each of these phases may take place, which can be interpreted as an ``overcooled gas'' phase when a small perturbation can change drastically gas into liquid. Mathematical analysis is accomplished in part by the exact derivation of the life-time of individual traffic jams for a given configuration of particles.Comment: 22 pages, 6 figures, corrected and improved version, to appear in the Journal of Statistical Physic

    A Water-Damaged Home and Health of Occupants: A Case Study

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    A family of five and pet dog who rented a water-damaged home and developed multiple health problems. The home was analyzed for species of mold and bacteria. The diagnostics included MRI for chronic sinusitis with ENT and sinus surgery, and neurological testing for neurocognitive deficits. Bulk samples from the home, tissue from the sinuses, urine, nasal secretions, placenta, umbilical cord, and breast milk were tested for the presence of trichothecenes, aflatoxins, and Ochratoxin A. The family had the following diagnosed conditions: chronic sinusitis, neurological deficits, coughing with wheeze, nose bleeds, and fatigue among other symptoms. An infant was born with a total body flare, developed multiple Cafe-au-Lait pigmented skin spots and diagnoses with NF1 at age 2. The mycotoxins were detected in bulk samples, urine and nasal secretions, breast milk, placenta, and umbilical cord. Pseudomonas aueroginosa, Acinetobacter, Penicillium, and Aspergillus fumigatus were cultured from nasal secretions (father and daughter). RT-PCR revealed A. fumigatus DNA in sinus tissues of the daughter. The dog had 72 skin lesions (sebaceous glands and lipomas) from which trichothecenes and ochratoxin A. were detected. The health of the family is discussed in relation to the most recent published literature regarding microbial contamination and toxic by-products present in water-damaged buildings
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