Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto

About: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto is a based out in . It is known for research contribution in the topics: Population & Genus. The organization has 2143 authors who have published 3674 publications receiving 71071 citations. The organization is also known as: FFCLRP & FFCLRP-USP.

Electrospray mass spectrometric and DFT study of substituent effects in Ag+ complexation to polycyclic aromatic hydrocarbons (PAHs)

Abstract: Complexation of Ag(I) cation to a series of substituted anthracenes (AN), phenanthrenes (PH), pyrenes (PY) and cyclopenta[a]phenanthrenes (CPaPH) was studied in competitive experiments by allowing PAHs to react in pairs with AgOTf. The resulting complexes were examined by electrospray mass spectrometry (ES-MS) to determine relative abundances of the corresponding monomeric and dimeric complexes. Based on this data a sequence of complexation ability rankings was derived for each group. Among the substituents examined, a -COMe group when placed at the meso position in AN and PH, or at the C-1 in PY is most effective in Ag+ complexation, whereas an -NO2 group is least efficient. Methyl groups at the meso positions are better than in the terminal rings. For the CPaPH series, bay region substitution (methyl and alkoxy) have limited effect as does carbonyl substitution in the annelated CP ring. In the PY series, a -COPh or a -CH(Me)OH group at C-1 is as efficient as -COMe. Based on extensive potential energy searches, four types of complexation modes were identified by B3LYP/LANL2DZ calculations involving Ag+ complexation to -NO2 oxygens, to -COMe or to -OH and a peri-carbon, to just one ring carbon, or by bridging two ring carbons. Among these modes, the first two are most favorable. The energetic preferences were rationalized with charge decomposition analysis (CDA). Effect of Ag+ complexation on relative aromaticity in various rings was examined by NICS (nucleus independent chemical shift) in two representative cases. Structures and energies of the acetyl pyrene–Ag+–pyrene hetero-dimer and acetyl pyrene–Ag+–acetyl pyrene homo-dimer complexes were determined with the same model. These complexes have sandwich structures.

Lanthanoid-Doped Phosphate/Vanadate Mixed Hollow Particles as Ratiometric Luminescent Sensors.

Abstract: Rare earth (RE) phosphates and vanadates are structurally similar compositions that display distinct but complementary luminescent properties. The properties of these phosphors can be combined in REPO4-REVO4 heterostructures during the development of new sensing technologies for biological applications. This work presents the synthesis of hollow RE phosphate/vanadate colloidal particles and evaluates their applicability as luminescent markers. Hydrothermal treatments of RE hydroxycarbonate particles in the presence of the PO43– and VO43– precursors afforded the final REPO4–REVO4 solids in a two-step template synthesis. We converted precursor hydroxycarbonate particles into the final heterostructures and characterized their structure and morphology. According to our detailed study into the spectroscopic properties of Eu3+-doped particles and their luminescence response to several species, the presence of the phosphate and vanadate phases in a single particle provided different chemical environments and ena...

Anticonvulsant and GABA uptake inhibition properties of venom fractions from the spiders Parawixia bistriata and Scaptocosa raptoria

Abstract: In this article we describe an in vivo anticonvulsant effect from denatured crude venom and partially isolated fractions from two spiders: Parawixia bistriata and Scaptocosa raptoria. Intracerebroventricular injections of these venoms and fractions abolished rat convulsive tonic-clonic seizures induced by picrotoxin, bicuculline and pentylenetetrazole, and also, inhibited GABA uptake in synaptosomes of rat cerebral cortex. The venoms described in this work seems to be promising tools for the study of the GABAergic system, and may be a potential source for new anticonvulsant drugs.

Genetic differentiation of the Euglossini (Hymenoptera, Apidae) populations on a mainland coastal plain and an island in southeastern Brazil.

Abstract: Euglossini bees are among the main pollinators of plant species in tropical and subtropical forests in Central and South America. These bees are known as long-distance pollinators due to their exceptional flight performance. Here we assessed through microsatellite loci the gene variation and genetic differentiation between populations of four abundant Euglossini species populations sampled in two areas, Picinguaba (mainland) and Anchieta Island, Ubatuba, Sao Paulo State, southeastern Brazil. There was no significant genetic differentiation between the island and mainland samples of Euglossacordata (Fst = 0.008, P = 0.60), Eulaemacingulata (Fst = 0.029, P = 0.29) and Eulaema nigrita (Fst = 0.062, P = 0.38), but a significant gene differentiation between mainland and island samples of Euglossa stellfeldi (Fst = 0.028, P = 0.016) was detected. As expected, our results showed that the water body that separates the island from the mainland does not constitute a geographic barrier for these Euglossini bees. The absence of populational structuring of three out the four species studied corroborates previous reports on those bees, characterized by large populations, with high gene diversity and gene flow and very low levels of diploid males. But the Eg. stellfeldi results clearly point that dispersal ability is not similar to all euglossine bees, what requires the development of different conservationist strategies to the Euglossini species.