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Optimisation and Validation of Dynamic Susceptibility Contrast MRI Perfusion Measurements

Popular Abstract in Swedish Med magnetkamera (magnetresonans, MR) kan utmärkt morfologisk information erhållas men tekniken är även användbar för funktionella studier. En funktionell tillämpning är att mäta perfusion (kapillära blodflöden). Perfusionsrelaterad information kan åskådliggöras på flera sätt med MR, ofta via signalförändringar orsakade av spårämnen eller kontrastmedel i blodet. Den teThe studies presented in this thesis concern the optimisation and evaluation of the dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) technique for the assessment of perfusion-related parameters of the brain, such as cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT). Several methodological factors influence these measurements, for example, contra

Time-resolved laser spectroscopy on high-lying states in neutral oxygen

Radiative lifetimes have been measured for five triplet states of atomic oxygen. The oxygen atoms were generated by photodissociation of NO2 and the investigated states were populated through a two-step process involving a two-photon excitation to the lowest excited triplet state of even parity, 2p33p 3P, followed by a one-photon excitation to the investigated state. A similar scheme is applicable

Influence of Internal Diffusional Limitations on the Performance of an Immobilized Enzyme in Organic Medium

The influence of mass-transfer limitations on the performance of immobilized a-chymotrypsin operating in acetonitrile medium has been investigated. The enzyme was immobilized by deposition on various porous carrier materials such as celite, polyamides of different particle sizes, controlled-pore glasses, polypropylene or polyacrylamides. When carrying out kinetically controlled peptide synthesis r

The (misconceived) distinction between internal and external validity

Researchers often aim to make correct inferences both about that which is actually studied (internal validity) and about what the results generalize to (external validity). The language of internal and external validity is not used by everyone, but many of us would agree that intuitively the distinction makes a lot of sense. Two claims are commonly made with respect to internal and external validi

Large Eddy Simulation of Complex Turbulent Flows

This thesis concerns the Large Eddy Simulation methodology and its application to predict complex turbulent flows at high Reynolds numbers, and at times also with high Mach numbers. The meaning of the word ?complex? refers both to the presence of complex flow phenomena and the, often, complex geometry of man-made devices restricting the flow. A fairly thorough evaluation study of the numerical met

List sequence turbo decoding techniques

An algorithm for decoding turbo codes that combines conventional turbo decoding and list sequence (LS) maximum a posteriori probability (MAP) decoding is presented and evaluated. Compared to previous results on this theme, a reduction in the order of 0.7 dB of the signal-to-noise ratio (SNR) is obtained for turbo codes with 514-bit pseudo-random interleaving at frame error rate (FER) 10-4 on the a

Beta Camera: Development and applications.

Popular Abstract in Swedish En ny bildgivande detektor för realtids registreringar av laddade partiklar (beta-partiklar, konversions-elektroner och alfa-partiklar) från tunna preparat har utvecklats, Betakamera. Den består av en ljuskänslig detektor, baserad på mikrokanalplattor, en fotokatod och en resistiv anod . Preparatet som ska registreras placeras mot en plastscintillator, vilken är monteraA new detector for on-line digital detection of charged particles (beta-particles, conversion electrons and alpha-particles) from thin samples for rapid autoradiography has been developed; the Beta Camera. The device consists of a photon-sensitive detector (image photon detector, IPD); the main component of which is a microchannel plate. The sample to be measured is mounted in close contact to a t

Tillgänglighet, närhet och synlighet – gemensamma utmaningar för LUB-nätverket för att möta forskares behov av stöd vid Lunds universitet

This report presents a project at Lund University Libraries (LUB) during the fall of 2012, with the object to identify areas where the present research support services ought to be developed and strengthened. The project is three folded and contains a) a literature review focusing on definitions and examples of research support services as well as researchers’ needs and experiences of support serv

Climate variability and its effects on regional hydrology: a case study for the Baltic Sea drainage basin

As climate models can be used to reproduce historical climates, the outcomes can be used to put climate extremes in to a proper historical perspective. This also allows investigation of nonlinear properties of hydrologic processes (e. g. precipitation, runoff) to better understand regional hydrologic dynamics. To this end, the present study uses results from a so-called 'paleosimulation' (i.e. sim