Quantifying photothermal heating at plasmonic nanoparticles by scanning electrochemical microscopy.

Photothermal heating at metal nanoparticles results from the non-radiative decay of localized surface plasmons. The local heat generation enhances the mass transport rate of redox molecules and causes a shift in their formal potential, both of which can impact an electrochemical process at the nanoparticle interface. Here we present a methodology for probing the surface temperature at a plasmonic nanoparticle substrate using scanning electrochemical microscopy (SECM). Light is used to excite a plasmonic substrate electrode, while an ultramicroelectrode tip is positioned close to the substrate to read out both the mass transfer rate and concentration profile of the redox molecules. The measured mass transfer rate and the shift in the equilibrium potential provide a quantitative value of the temperature increase at the substrate surface, which is verified by simulations using a mass transfer model coupled with heat dissipation. The developed SECM approach is suitable for probing heat generation at a variety of both plasmonic and non-plasmonic nanostructures.

The riddle of hyperlactatemia.

A recent observational study in a large cohort of critically ill patients confirms the association between hyperlactatemia and mortality. The mechanisms regulating the rates of lactate production and clearance in critical illness remain poorly understood. During exercise, hyperlactatemia clearly results from an imbalance between oxygen delivery and energy requirements. In critically ill patients, the genesis of hyperlactatemia is significantly more complex. Possible mechanisms include regional hypoperfusion, an inflammation-induced upregulation of the glycolitic flux, alterations in lactate-clearing mechanisms, and increases in the work of breathing. Understanding how these complex processes interact to produce elevations in lactate continues to be an important area of research.

The flavonoids and phenolic acids of the genus Silphium and their chemosystematic value.

The current review outlines the distribution of flavonoids and phenolic acids in eleven species of Silphium (Asteraceae). The chemosystematic significance of these findings is discussed and compared with DNA and morphological-based assignments for eleven species. Special attention is given to the five flavonol triglycosides that were previously isolated and characterized from Silphium species: isorhamnetin 3-O-alpha-L-rhamnosyl (1""-->6")-O-beta-D-galactopyranoside 7-O-beta-L-apiofuranoside (1), quercetin 3-O-alpha-L-rhamnosyl (1"'-->6")-O-beta-D-galactopyranoside 7-O-beta-L-apiofuranoside (2), quercetin 3-O-beta-L-galactosyl (1"'-->6")-O-beta-D-rhamnopyranoside 7-O-alpha-L-apiofuranoside (3), kaempferol 3-O-beta-D-apiofuranoside 7-O-alpha-L-rhamnosyl (1""-6"')-O-beta-D-galactopyranoside (4) and kaempferol 3-O-beta-D-apiofuranoside 7-O-alpha-L-rhamnosyl (1""-->6"')-O-beta-D (2"'-O-E-caffeoylgalactopyranoside) (5). In addition, several other known mono and diglycosidic flavonoids, along with 18 phenolic acids, were also identified and the structures of all of the compounds were established by LC/MS and NMR spectral investigations.

(S)-N-{3-[1-cyclopropyl-1-(2,4-difluoro-phenyl)-ethyl]-1H-indol-7-yl}-methanesulfonamide: a potent, nonsteroidal, functional antagonist of the mineralocorticoid receptor.

A novel, potent series of indole analogs were recently developed as MR antagonists, culminating in 14. This compound represents the first MR antagonist in this class of molecules, exhibiting picomolar binding affinity and in vivo blood pressure lowering at pharmaceutically relevant doses.

Enantiomeric separation of mineralocorticoid receptor (hMR) antagonists using the Chiralcel OJ-H HPLC column with novel polar cosolvent eluent systems.

This study demonstrates the increased versatility of the Chiralcel OJ-H stationary phase when using various alcohol/acetonitrile mobile phases. This chiral stationary phase has traditionally been employed in the normal phase mode and more recently with neat alcohols as eluents. Selected isomeric human mineralocorticoid receptor (hMR) antagonist pharmaceutical candidates and synthetic intermediates were separated using the Chiralcel OJ-H HPLC column with novel polar cosolvent eluent systems. The capacity factors, resolution, and selectivity of the chiral separations were assessed while varying the alcohol/acetonitrile composition and alcohol identity. The mixed polar eluents provide separations that are nearly always superior to both the traditional hexane-rich and single-alcohol "polar organic" eluents for the compounds tested in this article.