1,565 research outputs found

    A Sailor’s Disease Presenting in Urban America with Red Spots on the Legs

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    Sailors were often affected by nutritional deficiencies due to the absence of fresh foods on long voyages. One example is the development of scurvy from a lack of vitamin C ingestion. In modern society in which fresh food are available this disease is infrequently recognized. The following case describes a 62-year-old male who presented with “red spots” on his legs and a large area of ecchymosis on his thigh. After initial testing failed to elicit a cause, a dietary history revealed that the patient had a peculiar diet of only ice cream with a total avoidance of fruits and vegetables. This case highlights the importance of a good history and physical examination as the basis for medical diagnosis

    Long-range electron transfer in structurally engineered pentaammineruthenium (histidine-62) cytochrome c

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    In many biological processes, long-range electron transfer (ET) plays a key role. When the three-dimensional structures of proteins are accurately known, use of modified proteins and protein-protein complexes provides an experimental approach to study ET rates between two metal centers. For Ru(His)- modified proteins, the introduction of histidine residues at any desired surface location by site-directed mutagenesis opens the way for systematic investigations of ET pathways

    Progress on Ultrasonic Flaw Sizing in Turbine Engine Rotor Components: Bore and Web Geometries

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    The application of generic flaw sizing techniques to specific components generally involves difficulties associated with geometrical complexity and simplifications arising from a knowledge of the expected flaw distribution. This paper is concerned with the case of ultrasonic flaw sizing in turbine engine rotor components. The sizing of flat penny shaped cracks in the web geometry will be discussed and new crack sizing algorithms based on the Born and Kirchhoff approximations will be introduced. Additionally we propose a simple method for finding the size of a flat, penny shaped crack given only the magnitude of the scattering amplitude. The bore geometry is discussed with primary emphasis on the cylindrical focussing of the incident beam. Important questions which are addressed include the effects of diffraction and the position of the flaw with respect to the focal line. The appropriate deconvolution procedures to account for these effects will be introduced. Generic features of the theory will be compared with experiment. Finally, the effects of focused transducers on the Born inversion algorithm are discussed

    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

    Using Simulations To Investigate Decision-making In Airline Operations

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    This paper examines a range of methods to collect data for the investigation of decision-making in airline Operations Control Centres (OCCs). A study was conducted of 52 controllers in five OCCs of both domestic and international airlines in the Asia-Pacific region. A range of methods was used including: surveys, interviews, observations, simulations, and think-aloud protocol. The paper compares and evaluates the suitability of these techniques for gathering data and provides recommendations on the application of simulations

    Traditional family planning in Bangladesh

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    “Traditional” methods of family planning (FP) generally are methods such as withdrawal and periodic abstinence that do not require contraceptive substances or devices, or clinical procedures. In 1991, approximately 38 million couples worldwide relied on withdrawal to prevent pregnancy, and 30-35 million relied on periodic abstinence. Together, these constituted one-quarter of all users of temporary methods of FP worldwide. In Bangladesh, the proportion using periodic abstinence or withdrawal was more than 20 percent of users of temporary methods. The reasons for use of traditional methods have not been investigated in Bangladesh, because of overriding attention to modern methods. Given that the use of traditional methods is widespread, what is the level of knowledge among Bangladeshi users about the safe periods of the monthly cycle for the most effective use of periodic abstinence? What factors cause higher socioeconomic groups to be the main users of traditional methods? Why do some people switch between traditional and modern methods? This report investigates these questions, and others, but is aimed at determining the main policy issues and the policy implications of findings

    Line-profile tomography of exoplanet transits I: The Doppler shadow of HD 189733b

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    We present a direct method for isolating the component of the starlight blocked by a planet as it transits its host star, and apply it to spectra of the bright transiting planet HD 189733b. We model the global shape of the stellar cross-correlation function as the convolution of a limb-darkened rotation profile and a gaussian representing the Doppler core of the average photospheric line profile. The light blocked by the planet during the transit is a gaussian of the same intrinsic width, whose trajectory across the line profile yields a precise measure of the misalignment angle and an independent measure of v sin I. We show that even when v sin I is less than the width of the intrinsic line profile, the travelling Doppler "shadow" cast by the planet creates an identifiable distortion in the line profiles which is amenable to direct modelling. Direct measurement of the trajectory of the missing starlight yields self-consistent measures of the projected stellar rotation rate, the intrinsic width of the mean local photospheric line profile, the projected spin-orbit misalignment angle, and the system's centre-of-mass velocity. Combined with the photometric rotation period, the results give a geometrical measure of the stellar radius which agrees closely with values obtained from high-precision transit photometry if a small amount of differential rotation is present in the stellar photosphere.Comment: 8 pages, 5 figures, 2 tables; accepted by MNRA

    Line Broadening in Field Metal-poor Red Giant and Red Horizontal Branch Stars

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    We report 349 radial velocities for 45 metal-poor field red giant and red horizontal branch stars. We have have identified one new spectroscopic binary, HD 4306, and one possible such system, HD 184711. We also report 57 radial velocities for 11 of the 91 stars reported on previously by Carney et al. (2003). As was found in the previous study, radial velocity "jitter" is present in many of the most luminous stars. Excluding stars showing spectroscopic binary orbital motion, all 7 of the red giants with M(V) <= -2.0 display jitter, as well as 3 of the 14 stars with -2.0 <= M(V) <= -1.4. We have also measured line broadening in all of the new spectra, using synthetic spectra as templates. The most luminous red giants show significant line broadening, as do many of the red horizontal branch stars, and we discuss briefly possible causes.Comment: To appear in the Astronomical Journa
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