1,830 research outputs found

    Biological particle analysis by mass spectrometry

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    An instrument that analyzes the chemical composition of biological particles in aerosol or hydrosol form was developed. Efforts were directed toward the acquisition of mass spectra from aerosols of biomolecules and bacteria. The filament ion source was installed on the particle analysis by mass spectrometry system. Modifications of the vacuum system improved the sensitivity of the mass spectrometer. After the modifications were incorporated, detailed mass spectra of simple compounds from the three major classes of biomolecules, proteins, nucleic acids, and carbohydrates were obtained. A method of generating bacterial aerosols was developed. The aerosols generated were collected and examined in the scanning electron microscope to insure that the bacteria delivered to the mass spectrometer were intact and free from debris

    Characterizing Compromise Stability of Games Using Larginal Vectors

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    The core cover of a TU-game is a superset of the core and equals the convex hull of its larginal vectors. A larginal vector corresponds to an order of the players and describes the efficient payoff vector giving the first players in the order their utopia demand as long as it is still possible to assign the remaining players at least their minimum right. A game is called compromise stable if the core is equal to the core cover, i.e. the core is the convex hull of the larginal vectors. In this paper we describe two ways of characterizing sets of larginal vectors that satisfy the condition that if every larginal vector of the set is a core element, then the game is compromise stable. The first characterization of these sets is based on a neighbor argument on orders of the players. The second one uses combinatorial and matching arguments and leads to a complete characterization of these sets. We find characterizing sets of minimum cardinality, a closed formula for the minimum number of orders in these sets, and a partition of the set of all orders in which each element of the partition is a minimum characterizing set.Core;core cover;larginal vectors;matchings

    Solid-State Excitation Laser for Laser-Ultrasonics

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    The inspection speed of laser-ultrasonics compared with conventional ultrasonic testing is limited by the pulse repetition rate of the excitation laser. The maximum pulse repetition rate reported up to now for CO2-lasers, which are presently used for nearly all systems, is in the range of 400 Hz. In this paper a new approach based on a diode-pumped solid-state laser is discussed, which is currently being developed. This new excitation laser is designed for a repetition rate of 1 kHz and will operate at a mid-IR wavelength of 3.3 m. The higher repeti-tion rate enables a higher inspection speed, whereas the mid-IR wavelength anticipates a better coupling efficiency. The total power for pumping the laser crystals is transported via flexible optical fibres to the compact laser head, thus allowing operation on a robot arm. The laser head consists of a master oscillator feeding several lines of power amplifiers and in-cludes nonlinear optical wavelength conversion by an optical parametric process. It is char-acterized by a modular construction which provides optimal conditions for operation at high average power as well as for easy maintenance. These features will enable building reliable, long-lived, rugged, smart laser ultrasonic systems in futur

    Spectral properties and geology of bright and dark material on dwarf planet Ceres

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    Variations and spatial distributions of bright and dark material on dwarf planet Ceres play a key role in understanding the processes that have led to its present surface composition. We define limits for bright and dark material in order to distinguish them consistently, based on the reflectance of the average surface using Dawn Framing Camera data. A systematic classification of four types of bright material is presented based on their spectral properties, composition, spatial distribution, and association with specific geomorphological features. We found obvious correlations of reflectance with spectral shape (slopes) and age; however, this is not unique throughout the bright spots. Although impact features show generally more extreme reflectance variations, several areas can only be understood in terms of inhomogeneous distribution of composition as inferred from Dawn Visible and Infrared Spectrometer data. Additional material with anomalous composition and spectral properties are rare. The identification of the composition and origin of the dark, particularly the darkest material, remains to be explored. The spectral properties and the morphology of the dark sites suggest an endogenic origin, but it is not clear whether they are more or less primitive surficial exposures or excavated subsurface but localized material. The reflectance, spectral properties, inferred composition, and geologic context collectively suggest that the bright and dark material tends to gradually change toward the average surface over time. This could be because of multiple processes, i.e., impact gardening/space weathering, and lateral mixing, including thermal and aqueous alteration, accompanied by changes in composition and physical properties such as grain size, surface temperature, and porosity (compaction).Comment: Meteoritics and Planetary Science; Dawn at Ceres special issu

    Characterizing Compromise Stability of Games Using Larginal Vectors

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    The core cover of a TU-game is a superset of the core and equals the convex hull of its larginal vectors. A larginal vector corresponds to an order of the players and describes the efficient payoff vector giving the first players in the order their utopia demand as long as it is still possible to assign the remaining players at least their minimum right. A game is called compromise stable if the core is equal to the core cover, i.e. the core is the convex hull of the larginal vectors. In this paper we describe two ways of characterizing sets of larginal vectors that satisfy the condition that if every larginal vector of the set is a core element, then the game is compromise stable. The first characterization of these sets is based on a neighbor argument on orders of the players. The second one uses combinatorial and matching arguments and leads to a complete characterization of these sets. We find characterizing sets of minimum cardinality, a closed formula for the minimum number of orders in these sets, and a partition of the set of all orders in which each element of the partition is a minimum characterizing set.

    Diagnostic value of duplex ultrasound and liquid crystal contact thermography in preclinical detection of deep vein thrombosis after proximal femur fractures

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    During a prospective clinical study the diagnostic value of the two non-invasive examinations colour-coded duplex ultrasound (Duplex) and fluid crystal contact thermography (LCCT) was investigated in relation to phlebography, the standard examination for the diagnosis of deep vein thrombosis (DVT), in 112 patients with proximal femur fractures. In 19% of the patients, DVT was diagnosed by phlebography, with the main localisation in the lower leg in 19 of 21 (90%) thromboses. With a negative prediction value of 83%, Duplex is less suitable than LCCT under such difficult examination conditions as the early postoperative period. The specificity of Duplex is 95%, but the sensitivity only 18%. The specificity of LCCT is 85% and the sensitivity 75%. Considering the frequency of postoperative DVT after surgery on the legs, especially hip surgery, a postoperative screening for DVT should become mandatory. LCCT has proved to be a suitable, cheap, non-invasive examination with a negative prediction value of 94

    Prostate-specific antigen, sexual behavior, and sexually transmitted infections in US men 40–59 years old, 2001–2004: a cross – sectional study

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    <p>Abstract</p> <p>Background</p> <p>Sexually transmitted infections (STIs) are hypothesized to play a role in the development of prostate cancer, perhaps due to inflammation-induced oncogenesis. We assessed in a nationally representative population of middle-aged men whether sexual behavior indicators for an increased risk of genital infection were associated with serum prostate-specific antigen (PSA) concentration, a marker of prostatic disease and inflammation.</p> <p>Results</p> <p>The percentage of men between the ages of 40 and 59 with a PSA ≥ 4.0 ng/ml was 2.6% (95% confidence interval [CI], 1.8% – 3.8%). The percentage of men between the ages of 40 and 59 self-reporting a past diagnosis of genital warts or genital herpes, or a recent diagnosis of gonorrhea or chlamydia is estimated to be 7.3% (95% CI, 6.2% – 8.6%). Men self-reporting that they had had sex without using a condom in the past month had a lower PSA concentration and higher %fPSA than those who did not. There were no associations between any of the other sexual activity or laboratory measures and PSA or %fPSA.</p> <p>Conclusion</p> <p>In this nationally representative sample of middle-aged American men, we did not find consistent evidence for an association between sexual behavior or a history of STIs and PSA levels. Therefore, sexual factors are unlikely to lead to falsely elevated PSA tests in this population. We cannot rule out the role of these factors in causing false positive PSA tests in subgroups of the population that have a higher prevalence of high-risk sexual behavior, and more protracted or recent exposures to these agents.</p

    Haze at Occator crater on dwarf planet Ceres

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    A diurnal varying haze layer at the bright spots of Occator on dwarf planet Ceres has been reported from images of the Dawn Framing Camera. This finding is supported by ground-based observations revealing diurnal albedo changes at Occator's longitude. In the present work, we further investigate the previously reported haze phenomenon in more detail using additional Framing Camera images. We demonstrate that the light scattering behavior at the central floor of Occator is different compared to a typical cerean surface and is likely inconsistent with a pure solid surface scatterer. The identified deviation is best explained by an additional component to the scattered light of the surface, i.e., a haze layer. Our results support the water vapor detection by Herschel observations though the existence of a tenuous cerean exosphere is not yet confirmed.Comment: 2016 ApJL 833 L2

    Komplexe proximale Humerusfraktur beim alten Menschen: Winkelstabile Plattenosteosynthese vs. Hemiarthroplastik

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    Zusammenfassung: Hintergrund: Ziel der vorliegenden Untersuchung ist ein direkter Vergleich der Schulterhemiarthroplastik (SHA) mit der winkelstabilen Plattenosteosynthese (WSPOS) beim alten Patienten mit komplexer proximaler Humerusfraktur. Patienten und Methoden: Zwischen 2003 und 2005 wurden alle Patienten (n=52, Alter ≥70Jahre) mit 3- und 4-Segment-Frakturen des proximalen Humerus, welche mit einer WSPOS (PHILOS®) versorgt wurden, prospektiv erfasst und nach einem Jahr mittels Constant-Score (CS), Oxford Shoulder Score (OSS) und radiologisch nachkontrolliert. Verglichen wurde die WSPOS mit einem historischen Kollektiv mit identischen Einschlusskriterien, welches zwischen 1995 und 1997 an der gleichen Institution mittels SHA versorgt wurde (n=59). Ergebnisse: Beide Patientenkollektive zeigten keine Unterschiede bezüglich Alter, Geschlechterverteilung und Frakturtypen. Der CS war signifikant besser für die WSPOS (median 71 vs. 41). Bezüglich Schmerzen zeigte sich im OSS kein Unterschied zwischen den Gruppen. In der WSPOS-Gruppe mussten signifikant mehr Revisionseingriffe durchgeführt werden (25% vs. 2%). Schlussfolgerung: Die WSPOS liefert beim alten Patienten, bei komplexen proximalen Humerusfrakturen deutlich bessere funktionelle Resultate, ist jedoch mit mehr Rezidiveingriffen behaftet. Die Selbständigkeit der Patienten kann bei beiden Operationsmethoden bei guter Schmerzfreiheit meist erhalten werde
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