Universelle Miniatur-Signalauswertung fuer die Laser Doppler Anemometrie

Ein Laser Doppler Anemometer (LDA) ist ein beruehrungsloser optischer Sensor, der Stroemungsgeschwindigkeiten misst. Die Ueberlagerung zweier Laserstrahlen erzeugt im Schnittpunkt ein Messvolumen mit Inferenzstreifen. Ein Teilchen, das sich mit einer Stroemung durch das Messvolumen bewegt, streut mit der Doppelfrequenz des Doppler moduliertes Licht, das von einem Detektor empfangen wird. Die Frequenz des Doppler-modulierten Lichts ist der Geschwindigkeit des Teilchens proportional. Hier wird die technische Realisierung einer Auswerteelektronik fuer Laser Doppler Signale im Zeitbereich mit programmierbaren Gate-Arrays von Xilinx beschrieben. (orig.)A laser doppler anemometer (LDA) is a contactless optical sensor for flow rate measurement. Interference of two laser beams generates a measuring volume with interference lines in the point of intersection. A particle moving through the measuring volume with a current scatters light modulated wiith the doppler frequency, which is received by a detector. The frequency of the doppler-modulated light is proportional to the velocity of the particle. The report describes the technical details of an electronic evaluation system for laser doppler signals in the time range using programmable gate arrays by Xilinix. (orig.)SIGLEAvailable from TIB Hannover: RO 3132(32) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Quadratur-Signalauswertung fuer die Laser-Doppler-Anemometrie mit Field Programmable Gate Arrays (FPGA)

By processing of the phase angle-time course defined by a quadrature signal pair, the quadrature signal processing allowes the direct access to the local-time course of a scattered particle. At high chronological resolution the sign and magnitude of velocity and acceleration are obtained for each point within the measuring volume. Algorithms of signal processing suited for quadrature signal pairs have been developed, and a algorithm has been adapted for implementation in a quick, high-integrated programmable gate array from Xilinx. Technical realization of the processing electroncis as a modul can be adapted to different requirements in the laser doppler anemometry. (WEN)SIGLEAvailable from TIB Hannover: RO 3132(47) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Eigenschaften der Halbleiter der III. und V. Hauptgruppe-Elemente im festen und fluessigen Zustand und Erfassung ihrer stroemungsmechanischen Kennzahlen

SIGLEDEGerman

Untersuchung verschiedener optischer Eigenschaften von GaAlAs-Laserdioden und Si-Photodioden Vergleichsmessungen von Photoempfaengern in optischen Stroemungssensoren mit Halbleiterlaser- und Nd:YAG-Laser-Doppler-Anemometern. Rauschkompensation am 4-#pi#-LDA. Experimental investigation of the optical characteristics of diode lasers in cw- and high-frequency pulsed operation modes for LDA applications. Abschlussbericht

Within the framework of the R and D project, a variety of investigations were to be conducted. According to the priorities of investigations under this sub-project the results of this final report are not presented in a coherent form but rendered in three separate final reports. The use of a diode pumped solid state laser (Nd:YAG laser) is covered in the contribution 'Comparative Measurements of Photo Receivers in Optical Flow Sensors with Solid State Laseer Anemometers and Nd:YAG Laser Doppler Anemometers'. This report describes the configuration and testing of a laser doppler anemometer (LDA) with tunable optical output power. The planned investigations relating to the reduction of inherent noise of diode lasers by opposite phase superimposition of LDA signals with a laser diode reference signal have successfully be continued. The method can be used to eliminate disturbing pulses and amplitude noise of laser diodes, particularly disturbing influences in 4-#pi# LDA arrangements. The contribution 'Noise Compensation on the 4-#pi# LDA' describes the configuration and testing of the necessary components and presents results. The third contribution deals with planned investigations of high-frequency pulsed diode lasers. In particular the measurements of optical spectra and the determination of stable working points with pulsation have been successful. A comparison of the signal-to-noise ratio of LDAs with high-frequency pulsed lasers and cw operated laser diodes was also conducted. (orig./HM)Im Rahmen des F und E-Vorhabens waren vielfaeltige Untersuchungen durchzufuehren. Entsprechend den Untersuchungsschwerpunkten des Teilvorhabens sind die Ergebnisse im vorliegenden Abschlussbericht nicht in zusammenhaengender Form dargestellt, sondern in drei Abschlussteilberichten getrennt wiedergegeben. Mit dem Einsatz eines diodengepumpten Festkoerperlasers (Nd:YAG-Laser) befasst sich der Beitrag 'Vergleichsmessungen von Photoempfaengern in optischen Stroemungssensoren mit Halbleiterlaser- und Nd:YAG-Laser-Doppler-Anemometern'. Er beschreibt den Aufbau und die Erprobung eines Laser-Doppler-Anemometers (LDA) mit regelbarer optischer Ausgangsleistung. Die geplanten Untersuchungen zur Verringerung des inhaerenten Rauschens von Diodenlasern durch die gegenphasige Ueberlagerung der LDA-Signale mit einem Laserdioden-Referenzsignal wurden erfolgreich weitergefuehrt. Mit dem realisierten Verfahren koennen Stoerimpulse und Amplitudenrauschen von Laserdioden, fuer 4-#pi#-LDA-Anordnungen besonders stoerende Einfluesse, eliminiert werden. Der Beitrag 'Rauschkompensation and 4-#pi#-LDA' beschreibt Aufbau und Erprobung der notwendigen Komponenten und stellt die Resultate vor. Mit den vorgesehenen Untersuchungen an hochfrequent gepulsten Diodenlaser beschaeftigt sich der dritte Beitrag. Insbesondere die Messungen von optischen Spektren und die Ermittlung stabiler Arbeitspunkte bei Pulsation waren erfolgreich. Ein Vergleich des Signal-Rausch-Verhaeltnisses von LDA mit hochfrequent gepulsten und cw-betriebenen Laserdioden wurde ebenfalls durchgefuehrt. (orig./HM)SIGLEAvailable from TIB Hannover: F94B0747+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

The role of epoxide hydrolase Y113H gene variant in pancreatic diseases.

Contains fulltext : 81167.pdf (publisher's version ) (Closed access)OBJECTIVES: Chronic pancreatitis (CP) and pancreatic adenocarcinoma (pCA) are associated with risk factors such as alcohol intake and tobacco smoking. Microsomal epoxide hydrolase (EPHX1) is a phase II detoxifying enzyme capable of tobacco-borne toxicant inactivation. We studied the role of the EPHX1 c.337T>C (p.Y113H) variant, whichleads to altered enzyme activity, in pancreatic diseases. METHODS: We genotyped 2391 patients by melting curve analysis. We enrolled 367 patients with pCA, 341 patients with alcoholic CP (aCP), 431 patients with idiopathic CP or hereditary pancreatitis, 192 patients with acute pancreatitis, and 679 controls of German descent. We replicated data in 77 patients with aCP and 304 controls from The Netherlands. RESULTS: In German patients with aCP, Y113 was more common than in controls (allele frequencies, 0.73 vs 0.68; risk ratio, 1.21 [95% confidence interval, 1.05-1.39]). However, we could not confirm this association in the Dutch population (allele frequencies, 0.62 vs 0.68, P=not significant). In total, Y113 frequency was 0.71 in aCP and 0.68 in controls (P = not significant). Allele frequencies did not differ in the other disease groups (acute pancreatitis, 0.69; idiopathic CP or hereditary pancreatitis, 0.68; pCA, 0.68; and control, 0.68). CONCLUSIONS: The EPHX1 Y113H variant is not associated with pancreatic diseases indicating that EPHX1 does not play a significant role in the initiation of pancreatic inflammation or cancer

Evaluating Casama: Contextualized semantic maps for summarization of lung cancer studies

OBJECTIVEIt is crucial for clinicians to stay up to date on current literature in order to apply recent evidence to clinical decision making. Automatic summarization systems can help clinicians quickly view an aggregated summary of literature on a topic. Casama, a representation and summarization system based on “contextualized semantic maps,” captures the findings of biomedical studies as well as the contexts associated with patient population and study design. This paper presents a user-oriented evaluation of Casama in comparison to a context-free representation, SemRep.MATERIALS AND METHODSThe effectiveness of the representation was evaluated by presenting users with manually annotated Casama and SemRep summaries of ten articles on driver mutations in cancer. Automatic annotations were evaluated on a collection of articles on EGFR mutation in lung cancer. Seven users completed a questionnaire rating the summarization quality for various topics and applications.RESULTSCasama had higher median scores than SemRep for the majority of the topics (p ≤ 0.00032), all of the applications (p ≤ 0.00089), and in overall summarization quality (p ≤ 1.5e-05). Casama’s manual annotations outperformed Casama’s automatic annotations (p = 0.00061).DISCUSSIONCasama performed particularly well in the representation of strength of evidence, which was highly rated both quantitatively and qualitatively. Users noted that Casama’s less granular, more targeted representation improved usability compared to SemRep.CONCLUSIONThis evaluation demonstrated the benefits of a contextualized representation for summarizing biomedical literature on cancer. Iteration on specific areas of Casama’s representation, further development of its algorithms, and a clinically-oriented evaluation are warranted