Electrically detected magnetic resonance modeling and fitting: An equivalent circuit approach

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Infrared LED irradiation photobiomodulation of oxidative stress in human dental pulp cells

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Investigations on PVP/Y3BO6:Eu3+, a red Luminescent composite for lighting devices based on near UV-LEDs

This work deals with a red phosphor. Y3BO6:Eu3+, and its corresponding poly(N-vinylpyrrolidone) (PVP)/Y3BO6:Eu3+ luminescent composite film suitable for applications in the next generation of Hg-free lamps based on near ultraviolet (UV) light emitting diodes (LEDs). Well crystallized samples of Y3BO6 powders with the Eu3+ content up to 20 mol% were prepared by the Pechini method. After structural, morphological and optical characterization, the best doping rate of Eu3+ in the matrix was determined to be 15 mol%. This optimal powder, which is highly friable, was easily ground into fine particles and homogeneously dispersed into a PVP polymer solution to give rise to a polymer phosphor composite. Structural and optical features of the composite film have been studied and compared to those of a pristine PVP film and Y3BO6:Eu3+ powder. All the characterization (XRD, SAXS, luminescence...) proved that the red phosphor particles are well incorporated into the polymer composite film which exhibited the characteristic red emission of Eu3+ under UV light excitation. Furthermore, photostability of the polymer/phosphor composite film under UV-LED irradiation was evaluated from exposure to accelerated artificial photoageing at wavelengths above 300 nm.

Redes de neblina e armadilhas luminosas, uma nova proposta ao estudo de quirópteros

The use of light sources in combination with mist nets was tested in order to verify their efficiency for capturing insectivorous bats. Using a ultraviolet light emitting luminous attractive and 10 mist nets mounted in rows, reached the conclusion that such methodology should be futher studied before being efficiently used in order to inventory the species of bats in a region

Terapia fotodinâmica e luz branca: aspectos analíticos e perspectivas da viabilidade do tratamento

Photodynamic Therapy (PDT) is a technique used to treat several types of lesions, such as cancer, microbial control, and esthetic dentistry cases. The performance of PDT involves the use of a photosensitizer (PS), which mainly will be located in cancer cells and is irradiated with visible light. This process, when it occurs in the presence of oxygen triggers the formation of reactive oxygen species that are cytotoxic to cells. These species cause cell death and subsequent tumor necrosis. The use of white light as a light source for multispectral Photodynamic Therapy and its consequences to the photodynamic effect is not yet completely established, and therefore there is interest in studying the parameters involved for analyzing the best conditions for applying treatment. The wavelength is crucial to improve the therapeutic effect, since both the optical properties of the biological tissue as the PS depend on these parameters. For FS studied in this work (Photogem®) are most often used wavelengths in the red region, due to their larger penetration depth in biological tissue. Thus, the light source becomes a fundamental aspect, their choice depends on the specific application and is based on the tumor location, light dose to be delivered and FS chosen. Despite all the advantages presented by lasers, the fact of having an emission spectrum essentially monochrome makes only one possible transition possible for the absorption of FS is used. Therefore, more extensive light sources such as light emitting diodes (LED), could be better used in some cases the laser, with the additional advantage of a reduced cost. Therefore, the choice of the white LED comes from an emission spectrum that still wider LED colors defined by allowing greater use of the several absorption bands and with varying depths of operation, according to the wavelength... (Complete abstract click electronic access below)

Influência da luz LED em culturas de células-tronco mesenquimais in-vitro

Stem cells are defined as cells capable of self-renewal and differentiation into specialized cells when submited to external signalings in the enviroment. Among adult stem cells, mesenchymal cells occupy an important position because they can differentiate into mesodermal cells such as osteoblasts, adipocytes and chondrocytes. Cell therapy consists in the use of mesenchymal stem cells (MSC) in the treatment of degenerative diseases and harmed tissue reconstruction. Due to the longstanding and costly procedure for cultivation of MSC, it was proposed the use of low power light sources, such as light emitting diodes (LED), to optimize these factors. Recent works have shown a series of results from the influence of LED light on biological tissues such as increased rate of cell proliferation, increased RNA, DNA and ATP synthesis rate. The purpose of this study is to compare the biomodulator effect of LED light set at wavelengths 630nm ± 10nm and 805nm ± 10nm on the mesenchymal stem cells proliferation. For this, the mesenchymal stem cells culture adopted the procedure used in the Departament of Animal Reproduction and Veterinary Radiology of the Faculty of Veterinary Medicine and Animal Sciences of Botucatu. MSC were obtained from an adult horse bone marrow, and isolated by density gradient separation, with the FICOLL reagent and by centrifugation. The pellet containing the stem cells was removed and these were placed in low glucose DMEM culture medium, containing 10% fetal calf serum and antibiotics. The material was observed daily by inverted microscopy for monitoring the progression of the cells and subsequently the amount of cells were counted in a Neubauer counting chamber. The amount of MSC was obtained by cell culture seeded in 24 wells culture plate and segregated into three distinct groups: Group 1 was irradiated with wavelength set at 630nm ± 10 nm, Group... (Complete abstract click electronic access below)

Longitudinal effect of curcumin-photodynamic antimicrobial chemotherapy in adolescents during fixed orthodontic treatment: a single-blind randomized clinical trial study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photodynamic antimicrobial chemotherapy on streptococcus mutans using curcumin and toluidine blue activated by a novel LED device

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Transdentinal cell photobiomodulation using different wavelengths

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Resistência ao cisalhamento de bráquetes fotopolimerizados com arco de plasma, LED e luz halógena utilizando diferentes tempos

This study evaluated in vitro the shear bond strength of brackets bonded with xenon plasma arc light, light-emitting diode (LED) and conventional halogen light using different curing times. Brackets were bonded to the buccal surface of 60 human maxillary premolars allocated to five groups. In groups 1 and 2, the resin was cured with the plasma arc for three and six seconds (s), respectively; in groups 3 and 4, the LED was used for five and ten s, respectively; and in group 5, the halogen light was used for 40 s. The specimens were stored in water for 24 hours and subjected to a shear force until bracket failure. The debonding pattern was classified according to the adhesive remnant index (ARI). The results were assessed by Anova and the SNK post-hoc test. No differences were detected among groups 2, 4 and 5, which showed higher averages than groups 1 and 3, which were not different between themselves. The ARI scores showed no differences among the three types of light sources in all times tested. Plasma arc and LED lights can be used with shorter curing times, within certain limits, than conventional halogen light for bonding orthodontic brackets, without decreasing bond strength.

Photodynamic therapy in root canals contaminated with Enterococcus faecalis using curcumin as photosensitizer

The aim of the study was to evaluate the photodynamic therapy (PDT) effect on root canals contaminated with Enterococcus faecalis using a light emitting diode (LED) light and a curcumin solution (CUR) as photosensitizer (PS). Eighty root canals from uniradicular human teeth were prepared with Protaper Universal rotary system and contaminated with E. faecalis for 21 days. They were divided as: GIa-PDT (CUR, pre-irradiation for 5 + 5 min of irradiation); GIb-PDT (CUR, pre-irradiation for 5 + 10 min of irradiation); GIIa-(CUR, pre-irradiation for 5 + 5 min without irradiation); GIIb-(CUR pre-irradiation for 5 + 10 min of irradiation); GIIIa-(physiological solution and irradiation for 5 min); and GIIIb-(physiological solution and irradiation for 10 min); positive and negative control groups. Collections from root canals were made at time intervals of 21 days after contamination, immediately after treatment, and 7 days after treatment, and submitted to colony forming units per milliter (CFU mL-1) counts. The data were submitted to ANOVA and Tukey multiple comparison tests, at a level of significance of 5 %. In the immediate post-treatment collection, group GIa showed greater bacterial reduction in comparison with GIIa, GIIb, GIIIa, GIIIb, and positive control (P < 0.05). At 7 days post-treatment, GIa showed significant bacterial reduction only in comparison with GIIIa (P < 0.05). Curcumin as sensitizer was effective by 5 min LED irradiation but not by 10 min irradiation PDT using LED light, and curcumin as PS was not effective in eliminating E. faecalis. No difference was observed for periods of irradiation.

Efeito antimicrobiano de múltiplas sessões de tereapia fotodinâmica sobre biofilmes de Candida spp. formados in vitro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Hopping-tunneling model to describe electric charge injection at metal/organic semiconductor heterojunctions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of time exposure and low power sonochemical treatment on ZnO mesostructures

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Zirconium-methacrylate oxoclusters as new hybrid materials for the modification of epoxy systems

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)