Linear optical coherence tomography (LOCT) systems are a simple and robust alternative to time-domain optical coherence tomography systems, but a detector with approximately 10(4) pixels is needed ...for an imaging depth of 2 mm. We present a new system for LOCT with a special mask attached to the image sensor. The mask essentially performs a downconversion of the spatial frequencies by multiplication with a second spatial frequency. This reduces the fringe frequency of the optical coherence tomography signal so that the signal can be sampled with fewer pixels.
Zusammenfassung
Die konventionell-radiologische Diagnostik war über Jahrzehnte mit einer Gesamtgenauigkeit von 73% der unumstrittene Goldstandard in der bildgebenden Diagnostik des Dünndarms. In ...neuerer Zeit wird sie durch die Mehrzeilen-CT und moderne Kernspintomographie abgelöst. Die Sonographie eignet sich zur orientierenden Untersuchung des Dünndarms sowie zur Verlaufskontrolle bei speziellen Fragestellungen mit Sensitivitäten von 67–96% und einer Spezifität bis 97%. Die endoskopischen Untersuchungsverfahren des Dünndarms wie Kapselendoskopie und Doppelballonenteroskopie sind sehr zeit- und kostenintensive Verfahren, die bei gezielter Indikationsstellung jedoch wertvolle Informationen liefern. Anders als in anderen Bereichen des Gastrointestinaltrakts spielt die Diagnostik primärer Tumoren des Dünndarms aufgrund ihrer geringen Inzidenz von 3–5% aller gastrointestinalen Neoplasien eine eher untergeordnete Rolle, hier aber dann mit einer hohen Sensitivität von 84% und einer Spezifität bis zu 97% für CT und MRT. Vorherrschend sind Fragestellungen zur Ileusdiagnostik oder zur Diagnostik von Passagestörungen nach vorangegangenen Operationen zur Darstellung von Briden oder Verwachsungen sowie die Beteiligung des Dünndarms bei peritoneal metastasierenden Tumorerkrankungen. In der Primärdiagnostik des Morbus Crohn liegt die Per-Läsions-Sensitivität bei 47–68% für die Kapselendoskopie, 43% für die MRT und 21% für die CT-Enterographie. Bei Patienten mit bekanntem M. Crohn beträgt die Sensitivität im erneuten Schub 70% für die Kapsel und 79% für das MRT. Ein weiteres Indikationsfeld ist die Abklärung akuter und okkulter gastrointestinaler Blutungen.
This paper presents the MIMOSA architecture and development platform to create Ambient Intelligence applications. MIMOSA achieves this objective by developing a personal mobile-device centric ...architecture and open technology platform where microsystem technology is the key enabling technology for their realization due to its low-cost, low power consumption, and small size. This paper focuses the demonstration activities carried out in the field of health care. MIMOSA project is a European level initiative involving 15 enterprises and research institutions and universities.
Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence ...of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly-rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2-4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a neutron star extreme matter observatory (NEMO): a gravitational-wave interferometer optimized to study nuclear physics with merging neutron stars. The concept uses high circulating laser power, quantum squeezing and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above one kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year, and potentially allows for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.
The fuel-motion measurement capability of the fast-neutron hodoscope has been upgraded by the addition of a 360-detector proton-recoil proportional-counter array, which detects high-energy fission ...neutrons. The current sensitive amplifier/discriminator module for each detector fits into a 12.7- by 12.7- by 102-mm package and costs less than 100 per module. It has a 50-ns rise time, a noise level of 100 nA, and a deadtime per event of 200 ns. Provision has been provided for the independent adjustment of the input current versus discriminator voltage for each module. The new proportional-counters cost approximately 400 each. Each detector has been tested to have the same gain versus voltage response. A space-charge model relating count-rate changes to space-charge effects has also been developed. The new detector array has been operational for approximately two years and has become the main detector system in fuel-motion analysis. It has significantly improved the linearity, stability, count-rate capability, and setup ease of the hodoscope.
In this paper, carbon nanotubes/nanofibers for microwave amplifiers and parallel e-beam lithography have been discussed. Field emission properties of CN arrays will be presented.
PDF
