UNLABELLED PET permits the quantification of myocardial blood flow, but is hampered by the limited spatial resolution of PET images. METHODS We evaluated two methods for the correction of resolution effects in PET perfusion 13NH3-ammonia images. In one model, the spillover and recovery coefficients are estimated in the kinetic modeling analysis. The new, second model uses an explicit delineat...

Metabolic Control Analysis (MCA) is a powerful quantitative framework for understanding and explaining the relationships between the global steady-state properties of a cellular system in terms of control coefficients, and the local properties of the individual components of the system in terms of elasticities. The elasticities are apparent kinetic orders, which derive directly from the kinetic...

We have investigated the formation and early growth of atmospheric secondary aerosol particles building on atmospheric measurements. The measurements were part of the QUEST 2 campaign which took place in spring 2003 in Hyytiälä (Finland). During the campaign numerous aerosol particle formation events occurred of which 15 were accompanied by gaseous sulphuric acid measurements. Our detailed anal...

Direct numerical simulations ~DNS! are conducted to study the turbulence-chemical reaction interactions in homogeneous decaying compressible fluid flows. The reaction is of a single-step irreversible Arrhenius type. The results indicate that the heat of reaction has a noticeable influence on the solenoidal and the dilatational turbulent motions. The effect of reaction on the solenoidal velocity...

Tracer diffusion in a granular gas in simple shear flow is analyzed. The analysis is made from a perturbation solution of the Boltzmann kinetic equation through first order in the gradient of the mole fraction of tracer particles. The reference state (zeroth-order approximation) corresponds to a Sonine solution of the Boltzmann equation, which holds for arbitrary values of the restitution coeff...

A type of closed exterior algebra in R3 under the cross product is revealed to hold between differential forms from the three Whittaker scalar potentials, associated with the fields of a moving electron. A special algebraic structure is revealed in the context of Clebsch reparametrization of these scalars, and a special prescription for the construction of permutation invariant electromagnetic ...

Gas-phase autoxidation-regenerative peroxy radical formation following intramolecular hydrogen shifts-is known to be important in the combustion of organic materials. The relevance of this chemistry in the oxidation of organics in the atmosphere has received less attention due, in part, to the lack of kinetic data at relevant temperatures. Here, we combine computational and experimental approac...

An expression for the two-particle relaxation time of collective excitations on a distorted Fermi surface in diffusion approach to kinetic theory is obtained. The general case momentum-dependent and drift coefficients considered. temperature dependence obtained established.

Purpose: To directly compare HRRT (high resolution brain) and HR+ (standard wholebody) PET only scanners for quantitative brain studies using three tracers with vastly different tracer distributions. Procedures: Healthy volunteers underwent successive scans on HR+ and HRRT scanners (in random order) using either (R)-[C]verapamil (n=6), [C]raclopride (n=7) or [C]flumazenil (n=7). For all tracers...