Decorated titania fibers as photocatalysts for hydrogen generation and organic matter degradation

Heterogenous photocatalysts based on electrospun fibers composed of polyvinylpyrrolidone and titanium propoxide were prepared and heated at 500, 750 and 950 °C to obtain anatase and rutile fibers. The fibers were then decorated with Pd and Co nanoparticles as well as a symmetrical zinc phthalocyanine (Pc). The fibrous materials obtained have a paper-like macroscopic appearance allowing for easy handling and separation. The photocatalytic activities of the new materials were evaluated for the generation of H2 upon UV (368 nm) or visible (630 nm) light excitation. Depending on the heat treatment or the post-synthetic decoration method, the materials show higher, or similar, activity compared to P25-TiO2, with superior ease of separation. The catalysts showed ability to degrade organic matter, with MeOH used as a model compound. This is of considerable importance for potential water treatment applications that will require flow-compatible materials

Beyond Acetylene: Exploring Solvent Stabilization of Calcium Carbide‐derived Acetylide Intermediates and Their Significance in Small Organic Molecule Synthesis

The reaction of calcium carbide with water has been widely used as a source of acetylene for the synthesis of organic molecules. In contrast with this traditional approach, we use the CaC2 reaction under water-starved conditions and show reactions that involve a calcium acetylide intermediate, reminiscent of Grignard reaction intermediates, which are stabilized by the solvent. Using this reaction pathway may allow for new chemistry, finer reaction control, and safety by limiting the formation of acetylene gas during the reaction. For example, reaction with bromoarenes, readily yields the corresponding diaryl acetylene

Photocatalytic Hydrogen Generation Using Metal-Decorated TiO₂: Sacrificial Donors vs True Water Splitting

Photocatalytic Hydrogen Generation Using Metal-Decorated TiO₂: Sacrificial Donors vs True Water Splittin

Brain Serotonin Transporter Occupancy by Oral Sibutramine Dosed to Steady State: A PET Study Using 11C-DASB in Healthy Humans

Sibutramine is a centrally acting monoamine reuptake inhibitor prescribed as an appetite suppressant in the management of obesity. Its effects are mostly attributable to serotonin and norepinephrine transporter (SERT and NET, respectively) inhibition by its potent metabolites mono-desmethylsibutramine (M1) and di-desmethylsibutramine (M2). However, there is a paucity of in vivo data in humans about mechanisms underlying both clinical efficacy and the dose-independent non-response observed in a minority of patients. Twelve healthy male patients (mean age 41 years) completed a double-blind, placebo-controlled, within-subject crossover investigation of brain SERT occupancy by sibutramine 15 mg daily at steady state. Correlations were measured between occupancy and (i) plasma concentrations of sibutramine, M1 and M2; (ii) appetite suppression. 11C-DASB PET scans were performed on the HRRT camera. Binding potentials (BPND) were calculated by the Logan reference tissue (cerebellum) method. SERT occupancy was modest (mean 30±10%), was similar across brain regions, but varied widely across subjects (15–46%). Occupancy was correlated positively (p=0.09) with M2 concentration, but not with sibutramine or M1. No significant appetite suppression was seen at <25% occupancy and greatest suppression was associated with highest occupancy (25–46%). However, several subjects with occupancy (36–39%) in the higher range had no appetite suppression. SERT occupancy by clinical doses of sibutramine is of modest magnitude and may be mediated predominantly by M2 in humans. 5-HT reuptake inhibition may be necessary but is not sufficient for sibutramine's efficacy in humans, supporting preclinical data suggesting that the hypophagic effect requires the co-inhibition of both SERT and NET