Palladium-platinum electrocatalysts for the ethanol oxidation reaction: comparison of electrochemical activities in acid and alkaline media

Journal of Solid State Electrochemistry - Carbon-supported Pd, Pt, Pt1Pd1, and Pt3Pd1 electrocatalysts were prepared by metal ion chemical reduction with borohydride. The electrocatalysts were...     

New insight into the reaction of singlet oxygen with sulfur-containing cyclic alkenes: dye-sensitized photooxygenation of 5,6-dihydro-1,4-dithiins

The reaction of 3-methyl-5,6-dihydro-1,4-dithiins with singlet oxygen affords dicarbonyl compounds and/or ring-contracted ketosulfoxides, the latter regio- and stereoselectively, depending on the nature of the substituent at C-2 and on the reaction conditions. In competition with normal fragmentation, the intermediate dioxetanes, derived from [2 + 2] cycloaddition of singlet oxygen to the double bond, undergo an intramolecular oxygen transfer to the sulfur-1 atom, leading to labile epoxide intermediates. The latter convert to cis- and trans-ketosulfoxides through a non-concerted S-4 migration. This pathway is promoted by the electron-withdrawing group at C-2 and, for monosubstituted amide, by the solvent basicity. S-Oxidation of dithiins is insignificant, except for the monosubstituted amide derivative or in the presence of protic species, and occurs selectively at the S-1 atom.     

Propanediol (and) Caprylic Acid (and) Xylitol as a New Single Topical Active Ingredient against Acne: In Vitro and In Vivo Efficacy Assays

In addition to dermatological complications, acne can affect the quality of life of individuals in numerous ways, such as employment, social habits and body dissatisfaction. According to our expertise, caprylic acid and propanediol would not have a direct action on Cutibacterium acnes. Despite this, we investigated the existence of a synergistic effect among xylitol, caprylic acid and propanediol as a mixture of compounds representing a single topical active ingredient that could benefit the treatment against acne. In vitro and in vivo assays were performed to challenge and to prove the efficacy of propanediol, xylitol and caprylic acid (PXCA) against acne. PXCA had its MIC challenged against C. acnes (formerly Propionibacterium acnes) and Staphylococcus aureus, resulting in concentrations of 0.125% and 0.25%, respectively, and it also developed antimicrobial activity against C. acnes (time-kill test). PXCA was able to reduce the 5-alpha reductase expression in 24% (p < 0.01) in comparison with the testosterone group. By the end of 28 days of treatment, the compound reduced the skin oiliness, porphyrin amount and the quantity of inflammatory lesions in participants. According to the dermatologist evaluation, PXCA improved the skin’s general appearance, acne presence and size.     

Photoreactivity of triazolopyridinones, including the drug trazodone, in aqueous solution

Irradiation of triazolo[4,3-a]pyridin-3-ones at 310 nm has been investigated in water/acetonitrile (7%). Cis-cisoid-fused cyclobutanes are generally obtained. Cage products are found starting from derivatives bearing (piperazin-1-yl)aryl moiety under dilute conditions (10⁻³ M). Two different routes appear to be involved in the formation of the observed photoproducts. A plausible mechanistic explanation is reported.     

Reduction of Protein Networks Models by Passivity Preserving Projection

Reduction of complex protein networks models is of great importance. The accuracy of a passivity preserving algorithm (PRIMA) for model order reduction (MOR) is here tested on protein networks, introducing innovative variations of the standard PRIMA method to fit the problem at hand. The reduction method does not require to solve the complete system, resulting in a promising tool for studying very large-scale models for which the full solution cannot be computed. The mathematical structure of the considered kinetic equations is preserved. Keeping constant the reduction factor, the approximation error is lower for larger systems.     

Algorithm for accurate similarity measurements of peptide mass fingerprints and its application

We present a simple algorithm which allows accurate estimates of the similarity between peptide fingerprint mass spectra from matrix assisted laser desorption/ionization (MALDI) spectrometers. The algorithm, which is a combination of mass correlation and intensity rank correlation, was used to cluster similar spectra and to generate consensus spectra from a data store of more than 100,000 spectra. The resulting first spectra library of 1248 unambiguously identified different protein digests was used to search for missed cleavage patterns that have not been reported so far and to shed light on some peptide ionization characteristics. The findings of this study could be directly implemented in peptide mass fingerprint search algorithms to decrease the false positive error rate to <0.25%. Furthermore, the results contribute to the understanding of the peptide ionization process in MALDI experiments.     

Tailoring the interface using thiophene small molecules in TiO(2)/P3HT hybrid solar cells

In this paper we focus on the effect of carboxylated thiophene small molecules as interface modifiers in TiO(2)/P3HT hybrid solar cells. Our results show that small differences in the chemical structure of these molecules, for example, the presence of the -CH(2)- group in the 2-thiopheneacetic acid (TAA), can greatly increase the TiO(2) surface wettability, improving the TiO(2)/polymer contact. This effect is important to enhance exciton splitting and charge separation.     

Nanostructured diamine-fullerene derivatives: computational density functional theory study and experimental evidence for their formation via gas-phase functionalization

Nanostructure derivatives of fullerene C(60) are used in emerging applications of composite matrices, including protective and decorative coating, superadsorbent material, thin films, and lightweight high-strength fiber-reinforced materials, etc. In this study, quantum chemical calculations and experimental studies were performed to analyze the derivatives of diamine-fullerene prepared by the gas-phase solvent-free functionalization technique. In particular, the aliphatic 1,8-diamino-octane and the aromatic 1,5-diaminonaphthalene, which are diamines volatile in vacuum, were studied. We addressed two alternative mechanisms of the amination reaction via polyaddition and cross-linking of C(60) with diamines, using the pure GGA BLYP, PW91, and PBE functionals; further validation calculations were performed using the semiempirical dispersion GGA B97-D functional which contains parameters that have been specially adjusted by a more realistic view on dispersion contributions. In addition, we looked for experimental evidence for the covalent functionalization by using laser desorption/ionization time-of-flight mass spectrometry, thermogravimetric analysis, and atomic force microscopy.     

Rhodium and iridium complexes containing the anion of 1-phenyl-3-methyl-4-benzoyl- pyrazolone-5, a sophisticated analogue of β-diketones

Several (diolefin)M(A) complexes (M = Rh, Ir) were prepared, where AH is 1-phenyl-3-methyl- 4-benzoylpyrazolone-5, a very stable asymmetric analogue of acetylacetone. In these complexes the diolefin could be replaced by one mole of (Ph₂PCH₂CH₂)₂, two of CO or of PPh₃, or three of CNBu^t, while 1,10-phenanthroline displaced the chelating ligand to yield [(cyclooctadiene)Rh(phen)]⁺ (A)^?. Some compounds X?Y (X?Y = iodine or MeI) added oxidatively yielding the corresponding trivalent species. Using ³¹P NMR spectra the presence of the expected steric isomers was detected in (Ph₃P)(CO)Rh(A) and in (Ph₃P) (CO)Rh(A)(X)(Y).