Dilute magnetic semiconductor quantum-well structures for magnetic field tunable far-infrared/terahertz absorption

The design of ZnCdSe–ZnMnSe-based quantum wells is considered, in order to obtain a large shift of the peak absorption wavelength in the far infrared range, due to a giant Zeeman splitting with magnetic field, while maintaining a reasonably large value of peak absorption. A triple quantum-well structure with a suitable choice of parameters has been found to satisfy such requirements. A maximal tuning range between 14.6 and 34.7 meV is obtained, when the magnetic field varies from zero to 5 T, so the wavelength of the absorbed radiation decreases from 85.2 to 35.7 μm with absorption up to 1.25% at low temperatures. These structures might form the basis for magnetic field tunable photodetectors and quantum cascade lasers in the terahertz range

Magnetic field tunable terahertz quantum well infrared photodetector

A theoretical model and a design of a magnetic field tunable CdMnTe/CdMgTe terahertz quantum well infrared photodetector are presented. The energy levels and the corresponding wavefunctions were computed from the envelope function Schr¨odinger equation using the effective mass approximation and accounting for Landau quantization and the giant Zeeman effect induced by magnetic confinement. The electron dynamics were modeled within the self-consistent coupled rate equations approach, with all relevant electron-longitudinal optical phonon and electron-longitudinal acoustic phonon scattering included. A perpendicular magnetic field varying between 0 T and 5 T, at a temperature of 1.5 K, was found to enable a large shift of the detection energy, yielding a tuning range between 24.1 meV and 34.3 meV, equivalent to 51.4 μm to 36.1 μm wavelengths. For magnetic fields between 1 T and 5 T, when the electron population of the QWIP is spin-polarized, a reasonably low dark current of ≤1.4×10–² A/cm² and a large responsivity of 0.36−0.64 A/W are predicted

Zytologie der ableitenden Harnwege: Zwischen Zweifel und Gewissheit

Zusammenfassung: Wenig differenzierte Urothelkarzinome und das bioptisch oft schwierig fassbare Carcinoma in situ lassen sich im Gegensatz zu den "low-grade" urothelialen Neoplasien in der Urinzytologie zuverlässig diagnostizieren. Wir empfehlen folgendes Klassifikationssytem: negativ, zweifelhaft, suspekt und positiv. Angesichts der komplexen klinisch-pathologischen Zusammenhänge sollte die Klassifikation stets von einem Kommentar begleitet sein. Die 2004 WHO-Klassifikation der urothelialen Tumoren stellt die klinisch weniger relevanten "Low-grade-Tumoren" den klinisch relevanten "High-grade-Tumoren" gegenüber, die sich zytologisch meist als "positiv" klassifizieren lassen. Die zytologische Diagnose der zystoskopisch meist sichtbaren Low-grade-Neoplasien ist klinisch nicht dringlich. Urotheliale Neoplasien zeichnen sich im Gegensatz zu reaktiven Veränderungen durch chromosomale Aberrationen aus. Fluoreszenz-in-situ-Hybridisierung (FISH) mit mehreren DNS-Sonden eignet sich deshalb für die Abklärung unklarer Befunde. Bei eindeutig positiver Zytologie ist eine FISH-Untersuchung dagegen nicht notwendig. Eine standardisierte Diagnoseformulierung und die Möglichkeit zu weiteren Abklärungen mittels FISH erhöhen den diagnostischen Stellenwert der Harntraktzytologi

Radial Primary Angioplasty The Gold Standard Treatment for STEMI Patients∗

This is the author accepted manuscript.There is another ORE record for this publication: http://hdl.handle.net/10871/30367Challenges such as water scarcity and ever-increasing demand put an additional strain onto water distribution networks. Better asset management through leakage mitigation and demand forecasting can offset the current and future implications of these challenges. This paper shows how new high-resolution logging (e.g. 1 litre ticks) is able to enhance traditional methods of investigating leakages (e.g. minimum night flows) and instantiate novel methods for demand prediction (through micro-component analysis). Machine learning or other statistical analytical techniques coupled with the high-resolution data can be used in an adaptive way for leakage detection and demand forecasting. As a proof of concept, this paper investigates example datasets obtained from a UK based water company. The analyses suggest that it is possible to: extrapolate leakage from night flow time series data; predict water consumption patterns for different types of households and create consumption profiles based upon water user characteristics/behaviour.The authors would like to thank the EPSRC funding from WISE Centre for Doctoral Training. The authors also acknowledge the provision of anonymised data and financial support from South West Water, UK

Interplay between mesoscopic phase separation and bulk magnetism in the layered NaxCoO2

Specific heat of the layered NaxCoO2 (x=0.65, 0.70 and 0.75) oxides has been measured in the temperature range of 3-360 K and magnetic field of 0 and 9 T. The analysis of data, assuming the combined effect of inter-layer superexchange and the phase separation into mesoscopic magnetic domains with localized spins embedded in a matrix with itinerant electronic character, suggests that the dominant contribution to the specific heat in the region of short-range ordering is mediated by quasi-2D antiferromagnetic clusters, perpendicular to the CoO2 layers

DEVELOPMENT AND OPTIMIZATION OF CARVEDILOL FORMULATION USING EXPERIMENTAL DESIGN

The aim of this paper was to develop and optimize the carvedilol tablets formulation using the full factorial design. The content of binder (PVP K30), content of disintegrant (crospovidone) and main compression force were used as the independent variables. Tablets were prepared by wet granulation. The percentage of released carvedilol from prepared formulation after 10 minutes was defined as the response. It has been found that formulation with the low content of binding agents (4.8%), high content of disintegrant (4.5%) and compression force of 50 N has the best profile of drug. The optimal formulation was defined based on implementation of pharmaceuticaltechnological tests (testing strength, friability, disintegrating, contents of drug substance, drug release profiles). The stability of the optimal formulation with carvedilol was estimated using the aging tests

On the coherence/incoherence of electron transport in semiconductor heterostructure optoelectronic devices

This paper compares and contrasts different theoretical approaches based on incoherent electron scattering transport with experimental measurements of optoelectronic devices formed from semiconductor heterostructures. The Monte Carlo method which makes no a priori assumptions about the carrier distribution in momentum or phase space is compared with less computationally demanding energy-balance rate equation models which assume thermalised carrier distributions. It is shown that the two approaches produce qualitatively similar results for hole transport in p-type Si1-xGex/Si superlattices designed for terahertz emission. The good agreement of the predictions of rate equation calculations with experimental measurements of mid- and far-infrared quantum cascade lasers, quantum well infrared photodetectors and quantum dot infrared photodetectors substantiate the assumption of incoherent scattering dominating the transport in these quantum well based devices. However, the paper goes on to consider the possibility of coherent transport through the density matrix method and suggests an experiment that could allow coherent and incoherent transport to be distinguished from each other