Development of a Waveform Sampling ASIC with Femtosecond Timing for a Low Occupancy Vertex Detector.

Ph.D. Thesis. University of Hawaiʻi at Mānoa 2018

Nano- und Mikro Strukturierung von Nanokompositen auf Glas durch optische Raster-Nahfeldmikroskopie

Die Erzeugung von Strukturen im Bereich von Mikro- bzw. Nanometern ist eine wesentliche Voraussetzung für die Funktionalisierung von Glasoberflächen. Bis in den Bereich von 0,10 µm stellt die Lithografie die dominierende Strukturierungstechnik dar. Unterhalb dieser Abmessungen verhindern Beugungsphänomene die Erzeugung von noch kleineren Strukturen. Verbesserungen hinsichtlich der Auflösung konnten durch Verringerung der verwendeten Wellenlänge erzielt werden. Gleichzeitig erfordert dies die Entwicklung von Linsen, die im Bereich von λ~193 nm hinreichend durchlässig sind. Die lithografische Technik wurde zudem durch weiterführende Ansätze verbessert. Exemplarisch sei hier die Röntgenlithografie, extreme Ultraviolettlithografie, Elektronenstrahllithografie oder Rastersondenlithografie genannt. Rastersondenlithografie ist aufgrund ihrer hohen Auflösung von bis zu 20 nm eine der vielversprechendsten Methoden. Die vorliegende Arbeit beschäftigt sich aus diesem Grund mit der lithografischen Mikro- und Nanostrukturierung unter Verwendung der optischen Rasternahfeldmikroskopie (Scanning Near Field Optical Microskopie (SNOM)). SNOM-Lithografie kombiniert die etablierte Rastersondentechnik mit den Vorteilen der Nahfeldoptik und erreicht auf diese Weise Auflösungen im Bereich von Rasterelektronenmikroskopen (REM). Zudem besitzt die SNOM Methode den Vorteil, dass für den Betrieb kein Vakuum erforderlich ist. Eine Großserienproduktion oder großflächige Herstellung von strukturierten Oberflächen durch direktes Schreiben mit SNOM-Sonden auf ein Substrat ist ökonomisch nicht sinnvoll

Cyanine-Flavonol Hybrids for Near-Infrared Light-Activated Delivery of Carbon Monoxide

Carbon monoxide (CO) is an endogenous signaling molecule that controls a number of physiological processes. To circumvent the inherent toxicity of CO, light-activated CO-releasing molecules (photoCORMs) have emerged as an alternative for its administration. However, their wider application requires photoactivation using biologically benign visible and near-infrared (NIR) light. In this work, a strategy to access such photoCORMs by fusing two CO-releasing flavonol moieties with a NIR-absorbing cyanine dye is presented. These hybrids liberate two molecules of CO in high chemical yields upon activation with NIR light up to 820 nm and exhibit excellent uncaging cross-sections, which surpass the state-of-the-art by two orders of magnitude. Furthermore, the biocompatibility and applicability of the system in vitro and in vivo are demonstrated, and a mechanism of CO release is proposed. It is hoped that this strategy will stimulate the discovery of new classes of photoCORMs and accelerate the translation of CO-based phototherapy into practice

Six Studies in Nineteenth-Century English Literature and Thought

122 p. 23 cm. Includes bibliography University of Kansas autho

TELDOM: international network for diagnosis of pigmented skin lesions

TELDOM je naslov projekta, ki predvideva razvoj računalniške infrastrukture, ki bo zagotovila kvalitetno, uporabniku dostopno in preprosto uporabno modernoin natančno diagnostiko pigmentnih sprememb kože v ambulanti družinskega zdravnika. Digitalni posnetki, ki jih bo ta napravil, bodo po omrežju varno preneseni v specializirano ustanovo, kjer bodo postavili diagnozo in odgovor posredovali v zdravnikovo ambulanto. TELDOM bo omogočil tudi tesnejši kontakt med specialistom in družinskim zdravnikom in širjenje znanja iz specializiranih centrov na periferijo.TELDOM will provide a network infrastructure for delivering innovative, high quality, user friendlly and easy accessible medical services to citizens for diagnosis of pigmented skin lesions and tumors at the point of care regardlessof location by using advanced information technologies. Digital images will be send to th ecentres of excellence for diagnoses and returning to th e points of care. Contact between general physicians and specialists will be strenghtened and the transfer of medical knowledge from centers to remote areas intensified

Single electron Sensitive Readout (SiSeRO) X-ray detectors: Technological progress and characterization

Single electron Sensitive Read Out (SiSeRO) is a novel on-chip charge detector output stage for charge-coupled device (CCD) image sensors. Developed at MIT Lincoln Laboratory, this technology uses a p-MOSFET transistor with a depleted internal gate beneath the transistor channel. The transistor source-drain current is modulated by the transfer of charge into the internal gate. At Stanford, we have developed a readout module based on the drain current of the on-chip transistor to characterize the device. Characterization was performed for a number of prototype sensors with different device architectures, e.g. location of the internal gate, MOSFET polysilicon gate structure, and location of the trough in the internal gate with respect to the source and drain of the MOSFET (the trough is introduced to confine the charge in the internal gate). Using a buried-channel SiSeRO, we have achieved a charge/current conversion gain of >700 pA per electron, an equivalent noise charge (ENC) of around 6 electrons root mean square (RMS), and a full width half maximum (FWHM) of approximately 140 eV at 5.9 keV at a readout speed of 625 Kpixel/s. In this paper, we discuss the SiSeRO working principle, the readout module developed at Stanford, and the characterization test results of the SiSeRO prototypes. We also discuss the potential to implement Repetitive Non-Destructive Readout (RNDR) with these devices and the preliminary results which can in principle yield sub-electron ENC performance. Additional measurements and detailed device simulations will be essential to mature the SiSeRO technology. However, this new device class presents an exciting technology for next generation astronomical X-ray telescopes requiring fast, low-noise, radiation hard megapixel imagers with moderate spectroscopic resolution.Comment: To appear in SPIE Proceedings of Astronomical Telescopes + Instrumentation, 202

The high-speed X-ray camera on AXIS

AXIS is a Probe-class mission concept that will provide high-throughput, high-spatial-resolution X-ray spectral imaging, enabling transformative studies of high-energy astrophysical phenomena. To take advantage of the advanced optics and avoid photon pile-up, the AXIS focal plane requires detectors with readout rates at least 20 times faster than previous soft X-ray imaging spectrometers flying aboard missions such as Chandra and Suzaku, while retaining the low noise, excellent spectral performance, and low power requirements of those instruments. We present the design of the AXIS high-speed X-ray camera, which baselines large-format MIT Lincoln Laboratory CCDs employing low-noise pJFET output amplifiers and a single-layer polysilicon gate structure that allows fast, low-power clocking. These detectors are combined with an integrated high-speed, low-noise ASIC readout chip from Stanford University that provides better performance than conventional discrete solutions at a fraction of their power consumption and footprint. Our complementary front-end electronics concept employs state of the art digital video waveform capture and advanced signal processing to deliver low noise at high speed. We review the current performance of this technology, highlighting recent improvements on prototype devices that achieve excellent noise characteristics at the required readout rate. We present measurements of the CCD spectral response across the AXIS energy band, augmenting lab measurements with detector simulations that help us understand sources of charge loss and evaluate the quality of the CCD backside passivation technique. We show that our technology is on a path that will meet our requirements and enable AXIS to achieve world-class science.Comment: 17 pages, 11 figures, submitted to Proceedings of SPIE Optics + Photonics 202

Computer-aided detection in breast MRI: a systematic review and meta-analysis

To evaluate the additional value of computer-aided detection (CAD) in breast MRI by assessing radiologists' accuracy in discriminating benign from malignant breast lesions. A literature search was performed with inclusion of relevant studies using a commercially available CAD system with automatic colour mapping. Two independent researchers assessed the quality of the studies. The accuracy of the radiologists' performance with and without CAD was presented as pooled sensitivity and specificity. Of 587 articles, 10 met the inclusion criteria, all of good methodological quality. Experienced radiologists reached comparable pooled sensitivity and specificity before and after using CAD (sensitivity: without CAD: 89%; 95% CI: 78-94%, with CAD: 89%; 95%CI: 81-94%) (specificity: without CAD: 86%; 95% CI: 79-91%, with CAD: 82%; 95% CI: 76-87%). For residents the pooled sensitivity increased from 72% (95% CI: 62-81%) without CAD to 89% (95% CI: 80-94%) with CAD, however, not significantly. Concerning specificity, the results were similar (without CAD: 79%; 95% CI: 69-86%, with CAD: 78%; 95% CI: 69-84%). CAD in breast MRI has little influence on the sensitivity and specificity of experienced radiologists and therefore their interpretation remains essential. However, residents or inexperienced radiologists seem to benefit from CAD concerning breast MRI evaluation

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements