Dose-dependent effects of folic acid on blood concentrations of homocysteine: a meta-analysis of the randomized trials

Background: Dietary supplementation with B vitamins that lower blood homocysteine concentrations is expected to reduce cardiovascular disease risk, but there has been uncertainty about the optimum regimen to use for this purpose.

An Investigation into the Dissolution Properties of Celecoxib Melt Extrudates: Understanding the Role of Polymer Type and Concentration in Stabilizing Supersaturated Drug Concentrations

In this study, the dissolution properties of celecoxib (CX) solid dispersions manufactured from Eudragit 4155F and polyvinylpyrrolidone (PVP) were evaluated. Hot-melt extrusion (HME) technology was used to prepare amorphous solid dispersions of drug/polymer binary systems at different mass ratios. The drug concentrations achieved from the dissolution of PVP and Eudragit 4155F solid dispersions in phosphate buffer, pH 7.4 (PBS 7.4) were significantly greater than the equilibrium solubility of CX (1.58 µg/mL). The degree of supersaturation increased significantly as the polymer concentration within the solid dispersion increased. The maximum drug concentration achieved by PVP solid dispersions did not significantly exceed the apparent solubility of amorphous CX. The predominant mechanism for achieving supersaturated CX concentrations in PBS 7.4 was attributed to stabilization of amorphous CX during dissolution. Conversely, Eudragit 4155F solid dispersions showed significantly greater supersaturated drug solutions particularly at high polymer concentrations. For example, at a drug/polymer ratio of 1:9, a concentration of 100 µg/mL was achieved after 60 min that was stable (no evidence of drug recrystallization) for up to 72 h. This clearly identifies the potential of Eudragit 4155F to act as a solubilizing agent for CX. These findings were in good agreement with the results from solubility performed using PBS 7.4 in which Eudragit 4155F had been predissolved. In these tests, Eudragit 4155F significantly increased the equilibrium solubility of CX. Solution 1H NMR spectra were used to identify drug/polymer interactions. Deshielding of CX aromatic protons (H-1a and H-1b) containing the sulfonamide group occurred as a result of dissolution of Eudragit 4155F solid dispersions, whereas deshielding of H-1a protons and shielding of H-1b protons occurred as a result of the dissolution of PVP solid dispersions. In principle, it is reasonable to suggest that the different drug/polymer interactions observed give rise to the variation in dissolution observed for the two polymer/drug systems.

Origin of Low CO2 Selectivity on Platinum in the Direct Ethanol Fuel Cell

Calculated answer: First-principles calculations have been applied to calculate the energy barrier for the key step in CO formation on a Pt surface (see picture; Pt blue, Pt atoms on step edge yellow) to understand the low CO2 selectivity in the direct ethanol fuel cell. The presence of surface oxidant species such as O (brown bar) and OH (red bar) led to an increase of the energy barrier and thus an inhibition of the key step. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

The assimilation and chronic effects of sub-lethal concentrations of Endosulfan on condition and spawning in the common mussel Mytilus edulis

The rate of uptake of Endosulfan by Mytilus edulis L. exposed to pesticide concentrations of 0.1, 0.5, and 1.0 mg/l, and its subsequent elution on removal to clean sea water, was investigated. Higher residue levels were recorded for mussels exposed to higher concentrations of the pesticide, but concentration factors were reduced. There was a rapid initial fall in tissue residue levels on transfer to clean sea water due, it is suggested, to elution of Endosulfan adsorbed on particulate matter assimilated in the gut. The spawning period was prolonged at higher concentrations and, at 1.0 mg/l, the onset of spawning was delayed, possibly due to interference with gamonic action. At 0.1 mg/l, the minor protraction of the spawning period may reflect the effect of experimental tank conditions. No seasonal trend was obvious, and there was an exaggeration of the expected fall in condition in mussels exposed to higher concentrations of Endosulfan. In controls, the expected seasonal trend was reduced.

THE DETECTION OF HOT ETHANOL IN G34.3+0.15

Hot molecular cores in star-forming regions are known to have gas-phase chemical compositions determined by the evaporation of material from the icy mantles of interstellar grains, followed by subsequent reactions in the gas phase. Current models suggest that the evaporated material is rich in hydrogenated species, such as water, methane and methanol. In this paper, we report the detection of 14 rotational transitions of ethanol in the submillimetre spectrum of the molecular cloud associated with the ultra-compact H II region G34.3+0.15. We derive a rotation temperature of 125 K and a beam-averaged column density of 2.0x10(15) cm(-2), corresponding to a fractional abundance on the order of 4x10(-9). This large abundance, which is a lower limit due to the likelihood of beam dilution, cannot be made by purely gas-phase processes, and we conclude that the ethanol must be formed efficiently in the grain surface chemistry. Since it has been argued previously that methanol is formed via surface chemistry, it appears that alcohol formation may be a natural by-product of surface reactions.

Effect of atorvastatin on circulating hsCRP concentrations: A sub-study of the Achieve Cholesterol Targets Fast with Atorvastatin Stratified Titration (ACTFAST) study

Background: Elevated C-reactive protein (CRP) concentration is a risk factor for cardiovascular events that may add prognostic information. Statin treatment is associated with significant reductions in CRP concentrations, which appear to be unrelated to the magnitude of LDL-cholesterol reduction. We investigated the effect of atorvastatin, across its dose range, on high sensitivity (hs)CRP in subjects at high cardiovascular risk. Methods: ACTFAST was a 12 week, prospective, multicenter, open-label trial in which high-risk subjects were assigned a starting dose of atorvastatin (10, 20, 40 or 80 mg/d) based on LDL-C and status of statin use at screening (1345 statin-free [ SF] and 772 previously statin-treated [ST]). Results: At baseline, ST subjects had significantly lower hsCRP levels than SF subjects (ST group 2.31, 95% CI 2.15, 2.48 mg/L vs. SF group 3.16, 95% CI 2.98, 3.34 mg/L, p