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 & Catalysis. The organization has 2143 authors who have published 3674 publications receiving 71071 citations. The organization is also known as: FFCLRP & FFCLRP-USP.

Effect of the vanadium(V) concentration on the spectroscopic properties of nanosized europium-doped yttrium phosphates

Abstract: Nanosized rare earth phosphovanadate phosphors (Y(P,V)O4:Eu3+) have been prepared by applying the organic–inorganic polymeric precursors methodology. Luminescent powders with tetragonal structure and different vanadate concentrations (0%, 1%, 5%, 10%, 20%, 50%, and 100%, with regard to the phosphate content) were then obtained for evaluation of their structural and spectroscopic properties. The solids were characterized by scanning electron microscopy, X-ray diffractometry, vibrational spectroscopy (Raman and infrared), and electronic spectroscopy (emission, excitation, luminescence lifetimes, chromaticity, quantum efficiencies, and Judd–Ofelt intensity parameters). The solids exhibited very intense 5D0 → 7FJ Eu3+ transitions, and it was possible to control the luminescent characteristics, such as excitation maximum, lifetime and emission colour, through the vanadium(V) concentration. The observed luminescent properties correlated to the characteristics of the chemical environments around the Eu3+ ions with respect to the composition of the phosphovanadates. The Eu3+ luminescence spectroscopy results indicated that the presence of larger vanadium(V) amounts in the phosphate host lattice led to more covalent and polarizable chemical environments. So, besides allowing for control of the luminescent properties of the solids, the variation in the vanadate concentration in the obtained YPO4:Eu3+ phosphors enabled the establishment of a strict correlation between the observable spectroscopic features and the chemical characteristics of the powders.

Egg Production Strategies of the Tropical Hermit Crab Paguristes Tortugae from Brazil

Abstract: The aim of the present study was to characterize the total and seasonal fecundity of the hermit crab Paguristes tortugae as well as the influence of shell type on fecundity using the morphometric relationship. Ovigerous females were collected monthly from January to December, 1998, in the infralittoral region of Anchieta Island. Samplings were performed using SCUBA. The hermit crabs and the gastropod shells were measured. Hermit wet weight and shell dry weight were recorded. For the fecundity analysis, only ovigerous females with the eggs in the early phase of development were selected. The number of eggs carried by individuals of several sizes (shield length), condition of development, and egg size were determined. A high percentage (69.88%) of ovigerous females with eggs in the early phase of development were captured, with a low frequency (4.29%) of females with eggs in the final stage of development. Size-frequency distribution during the months showed two peaks in the ovigerous female popula...

Quantification of fractal dimension and Shannon's entropy in histological diagnosis of prostate cancer.

Abstract: Prostate cancer is a serious public health problem that affects quality of life and has a significant mortality rate. The aim of the present study was to quantify the fractal dimension and Shannon’s entropy in the histological diagnosis of prostate cancer. Thirty-four patients with prostate cancer aged 50 to 75 years having been submitted to radical prostatectomy participated in the study. Histological slides of normal (N), hyperplastic (H) and tumor (T) areas of the prostate were digitally photographed with three different magnifications (40x, 100x and 400x) and analyzed. The fractal dimension (FD), Shannon’s entropy (SE) and number of cell nuclei (NCN) in these areas were compared. FD analysis demonstrated the following significant differences between groups: T vs. N and H vs. N groups (p < 0.05) at a magnification of 40x; T vs. N (p < 0.01) at 100x and H vs. N (p < 0.01) at 400x. SE analysis revealed the following significant differences groups: T vs. H and T vs. N (p < 0.05) at 100x; and T vs. H and T vs. N (p < 0.001) at 400x. NCN analysis demonstrated the following significant differences between groups: T vs. H and T vs. N (p < 0.05) at 40x; T vs. H and T vs. N (p < 0.0001) at 100x; and T vs. H and T vs. N (p < 0.01) at 400x. The quantification of the FD and SE, together with the number of cell nuclei, has potential clinical applications in the histological diagnosis of prostate cancer.

Production of reactive oxygen and nitrogen species by light irradiation of a nitrosyl phthalocyanine ruthenium complex as a strategy for cancer treatment

Abstract: Production of reactive oxygen species has been used in clinical therapy for cancer treatment in a technique known as Photodynamic Therapy (PDT). The success of this therapy depends on oxygen concentration since hypoxia limits the formation of reactive oxygen species with consequent clinical failure of PDT. Herein, a possible synergistic effect between singlet oxygen and nitric oxide (NO) is examined since this scenario may display increased tumoricidal activity. To this end, the trinuclear species [Ru(pc)(pz)2{Ru(bpy)2(NO)}2](PF6)6(I) (pc = phthalocyanine; pz = pyrazine; bpy = bipyridine) was synthesized to be a combined NO and singlet oxygen photogenerator. Photobiological assays using (I) at 4 × 10−6 M in the B16F10 cell line result in the decrease of cell viability to 21.78 ± 0.29% of normal under light irradiation at 660 nm. However, in the dark and at the same concentration of compound (I), viability was 91.82 ± 0.37% of normal. The potential application of a system like (I) in clinical therapy against cancer may be as an upgrade to normal photodynamic therapy.