Signal-to-noise ratio,contrast-to-noise ratio and pharmacokinetic modeling considerations in dynamic contrast-enhanced magnetic resonance imaging

With advances in magnetic resonance imaging (MRI) technology, dynamic contrast-enhanced (DCE)-MRI is approaching the capability to simultaneously deliver both high spatial and high temporal resolutions for clinical applications. However, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) considerations and their impacts regarding pharmacokinetic modeling of the time-course data continue to represent challenges in the design of DCE-MRI acquisitions. Given that many acquisition parameters can affect the nature of DCE-MRI data, minimizing tissue-specific data acquisition discrepancy (among sites and scanner models) is as important as synchronizing pharmacokinetic modeling approaches.     

Development and applications of a sample controlled DSC system

The development of a new sample controlled thermal analysis technique based on a heat flux DSC is described. The performance of the system is demonstrated by studies on the decomposition of sodium bicarbonate and the oxidation of a copper impregnated carbon. The ability of the technique to study reactions which take place without a change in mass is illustrated by the curing of an epoxy resin with a polyaminoamide hardener.     

Bond-shift rearrangement during hydrogenolysis of neopentyl iodide on group VIII metal catalysts. An analogue of the mechanism of action of vitamin B12

The hydrogenolysis of neopentyl iodide on reduced Co or Pt dispersed on MgO support yields increasing amounts of 2-metylbutane and 2-methylbutenes in addition to neopentane, as the temperature is raised from 50 to 150°C. These results support the idea that a π-complexed half-reaction state is simultaneously involved in activation of the R---I bond and in the evident 1,2-methyl shift. This π-complex mechanism is the same as that first suggested almost a quarter of a century ago for neopentane isomerism during hydrogenolysis at 200°C on Pt catalysts. The present results also support the contention that similar π-complexes are responsible for analogous carbon skeleton rearrangement reactions mediated by coenzyme B₁₂.     

An investigation of strontium nitrite and its role in the ageing of the magnesium-strontium nitrate pyrotechnic system using isothermal microcalorimetry and thermal analysis techniques

A sample of strontium nitrite has been synthesised and thermally characterised to investigate its role in the ageing of magnesium-strontium nitrate pyrotechnic compositions in the presence of water vapour. Studies by isothermal microcalorimetry show that the addition of strontium nitrite to a 50% magnesium-50% strontium nitrate composition eliminated the induction reaction normally observed in closed ampoule studies in air at 50 °C and relative humidities in the range 65-69%.     

Tricyclic chemistry. Synthesis and chemistry of a novel polyheterocycle

The photochemical reaction of 1 with acrylonitrile gave the cyclobutane adducts II and III, which on treatment with base afforded a novel polycyclic structure IV. Reduction of IV with LAH followed by Eschweiler-Clarke methylation yielded the polyheterocyclic structure VI.     

1,8-Naphthyridines. Part I. Synthesis of some trifluoromethyl-1,8-naphthyridine derivatives

The synthesis of some 2-amino-1,8-naphthyridine derivatives substituted in the 5- and/or 7-positions with trifluoromethyl is described along with their conversions to the corresponding 1,8-naphthyridin-2(1H)ones. A modified procedure for oxidizing electron-deficient heterocyclic compounds to their N-oxides is presented.     

Sauerstoffbestimmung

Ohne Zusammenfassung