BACKGROUND AND PURPOSE The Patlak model has been applied to first-pass perfusion CT (PCT) data to extract information on blood-brain barrier permeability (BBBP) to predict hemorrhagic transformation in patients with acute stroke. However, the Patlak model was originally described for the delayed steady-state phase of contrast circulation. The goal of this study was to assess whether the first p...

In quantitative dynamic PET studies, graphical analysis methods including the Gjedde-Patlak plot, the Logan plot, and the relative equilibrium-based graphical plot (RE plot) (Zhou Y., Ye W., Brasić J.R., Crabb A.H., Hilton J., Wong D.F. 2009b. A consistent and efficient graphical analysis method to improve the quantification of reversible tracer binding in radioligand receptor dynamic PET studi...

We describe a patient with general paresis who developed progressive dementia and a cerebellar syndrome including wide-based gait, slurred speech, and intention tremor. Quantitative analysis by means of a Patlak plot of single-photon emission computed tomography (SPECT) with 99mTc-ethyl cysteinate dimer showed generally low blood flow in the cerebrum and the cerebellum. After antisyphilitic the...

Material and methods 13 patients with histopathologically proven oesophageal adenocarcinoma underwent a combined dynamic and static F-FDG PET/CT including CT tumour perfusion (Siemens, Biograph mCT). Dynamic PET (listmode) was acquired for 60 min resulting in 38 frames from 10 to 600 sec duration for the full dynamic dataset and 2 frames each with 600 sec duration (20-30 min and 50-60 min p.i.)...

Here hi = uiφ − ūiφ̄ is the SGS scalar flux. Both τij and hi are not available from the resolved (LES) flow field and thus have to be modeled. A very promising approach to modeling τij and hi consists of utilization of extra LES quantities such as SGS kinetic energy (Schumann 1975; Ghosal et al. 1995) and SGS scalar variance (Jiménez et al. 2001; Chumakov & Rutland 2004, 2005). For these quantit...

The Boltzmann-plot (BPT) method for laboratory plasma diagnostic was used for a quick estimate of physical conditions in the Broad Line Region (BLR) of 14 Active Galactic Nuclei (AGNs). For the BLR of nine AGNs, where PLTE exist, the estimated electron temperature are in the range T∼ 130000K 37000K are in good agreement with previous estimates. The estimated electron densities depend on the opa...

Recently, there has been a wide interest in the study of aggregation equations and Patlak-Keller-Segel (PKS) models for chemotaxis with degenerate diffusion. The focus of this paper is the unification and generalization of the well-posedness theory of these models. We prove local well-posedness on bounded domains for dimensions d ≥ 2 and in all of space for d ≥ 3, the uniqueness being a result ...

A finite volume method is presented to discretize the Patlak-Keller-Segel (PKS) model for chemosensitive movements. On the one hand, we prove existence and uniqueness of a numerical solution to the proposed scheme. On the other hand, we give a priori estimates and establish a threshold on the initial mass, for which we show that the numerical approximation convergences to the solution to the PK...

Although a vast amount of literature exists on the selection of an appropriate probubility distribution for annual maximum fluodflows, few studies huve examined which probability distributions ure most suitable to fit to sequences of annual minimum streamflow!;. Probabilily plots have been u!;ed widely in hydrology as a gruphicul uid to assess the goodnes!; of fu of ultemative distributions. Re...