Universidade de Pernambuco

About: Universidade de Pernambuco is a education organization based out in Recife, Brazil. It is known for research contribution in the topics: Population & Medicine. The organization has 6147 authors who have published 6948 publications receiving 73648 citations.

Impact of remineralizing agents on enamel microhardness recovery after in-office tooth bleaching therapies.

Abstract: Objective. It has been shown that bleaching with 35/38% hydrogen peroxides may alter both enamel morphology and mineral content. This study aimed to analyze the morphology and microhardness of enamel bleached with in-office hydrogen peroxides and exposed toremineralizing agents. Materials and methods. After recording initial enamel morphology and microhardness, 60 bovine incisors were bleached using either a calcium-containing 35% hydrogen peroxide (Whiteness HP Blue) or a calcium-free 35% hydrogen peroxide (Whitegold Office) (n = 30). Then, the teeth were subjected to one of three post-bleaching remineralizing treatments (n = 10): storage in artificial saliva only, application of a sodium fluoride gel or application of a nanohydroxyapatite-based agent (Nano-P). After 24 h and 14 days of post-bleaching treatments, the enamel morphology and microhardness were re-evaluated. The microhardness data were analyzed by means of two-way ANOVA with repeated measurements and Tukey tests (p < 0.05), while th...

Biomodulatory effects of lllt on bone regeneration

Abstract: Tissue healing is a complex process that involves local and systemic responses. The use of Low Level Laser Therapy (LLLT) for wound healing has been shown to be effective in modulating both local and systemic response. Usually the healing process of bone is slower than that of soft tissues. The effects of LLLT on bone are still controversial as previous reports show different results. This paper reports recent observations on the effect of LLLT on bone healing. The amount of newly formed bone after 830nm laser irradiation of surgical wounds created in the femur of rats was evaluated morphometricaly. Forty Wistar rats were divided into four groups: group A (12 sessions, 4.8J/cm2 per session, 28 days); group C (three sessions, 4.8J/cm2 per session, seven days). Groups B and D acted as non-irradiated controls. Forty eight hours after the surgery, the defects of the laser groups were irradiated transcutaneously with a CW 40mW 830nm diode laser, (f∼1mm) with a total dose of 4.8J/cm2. Irradiation was performed three times a week. Computerized morphometry showed a statistically significant difference between the areas of mineralized bone in groups C and D (p=0.017). There was no significant difference between groups A and B (28 days) (p=0.383). In a second investigation, we determined the effects of LLLT on bone healing after the insertion of implants. It is known that dental implants need four and six months period for fixation on the maxillae and on the mandible before receiving loading. Ten male and female dogs were divided into two groups of five animals that received the implant. Two animals of each group acted as controls. The animals were sacrificed 45 and 60 days after surgery. The animals were irradiated three times a week for two weeks in a contact mode with a CW 40mW 830nm diode laser, (f ∼1mm) with a total dose per session of 4.8J/cm2 and a dose per point of 1.2J/cm2. The results of the SEM study showed better bone healing after irradiation with the 830nm diode laser. These findings suggest that, under the experimental conditions of the investigation, the use of LLLT at 830nm significantly improves bone healing at early stages. It is concluded that LLLT may increase bone repair at early stages of healing.

Particle Swarm Optimization of Neural Network Architectures andWeights

Abstract: The optimization of architecture and weights of feed forward neural networks is a complex task of great importance in problems of supervised learning. In this work we analyze the use of the particle swarm optimization algorithm for the optimization of neural network architectures and weights aiming better generalization performances through the creation of a compromise between low architectural complexity and low training errors. For evaluating these algorithms we apply them to benchmark classification problems of the medical field. The results showed that a PSO-PSO based approach represents a valid alternative to optimize weights and architectures of MLP neural networks.

Validity of physical activity and food consumption questionnaire for children aged seven to ten years old

Abstract: OBJECTIVES: assess reproducibility and concurrent validity of the questionnaire focusing on a typical physical activity and food intake day (DAFA) to measure physical activity and food intake in children between seven and ten years old. METHODS: sixty nine children recruited in a public school located in Florianopolis, Santa Catarina participated of the survey. Reproducibility was determined by comparing measures of two DAFA applications in a two week interval while concurrent validity of physical activity was assessed by comparing DAFA with a questionnaire filled by parents/teachers. As for food intake, the reference method was a 24 hour recordatory. Analysis included concordance coefficient determination, intraclass correlation, adjusted kappa coefficient and Wilcoxon and Kruskal-Wallis tests. RESULTS: concordance coefficient was of 88% (school commuting) and 68% (physical activity related attitude) while intraclass correlation was of 0.85 for the general measure for physical activity. Using the report of parents/teachers, the children were broken into three groups of physical activities (low/medium/high), it should be considered that DAFA scores differed significantly. As for food intake measuring, 80% of concordance was determined between DAFA applications. Interinstrument convergence was substantial/moderate in relation to 17 food items. CONCLUSIONS: DAFA allows for physical activity and food intake measures in children with good reproducibility and moderate validation evidence.

Chronic treatment with sildenafil stimulates Leydig cell and testosterone secretion

Abstract: The phosphodiesterase type 5 (PDE5) inhibitor, Sildenafil, is a novel, oral treatment approach for pulmonary hypertension. As Leydig cells present PDE5, this study was conducted to investigate the effects of the chronic treatment with Sildenafil (25 mg/kg) on male Swiss Webster mice steroidogenesis. After a 4-week long experimental design, Leydig cells were analysed by morphological and immunocytochemical procedures. Serum testosterone was assayed by radioimmunoassay. Leydig cells presented noteworthy ultrastructural alterations, such as a vesicular smooth endoplasmic reticulum, large vacuoles scattered through the cytoplasm, enlarged mitochondria with discontinue cristaes and whorle membranes with vesicles at the periphery, which are typical characteristics of an activated steroid-secreting cell. Important immunocytochemical labelling for steroidogenic acute regulatory protein, cytochrome P450 side-chain cleavage enzyme and testosterone were detected in isolated Leydig cells. In addition, Sildenafil-treated mice showed significant increased levels of total testosterone. The results obtained in the present study are consistent with the hypothesis that the accumulation of cyclic guanosine monophosphate by PDE5 inhibition could be involved in the androgen biosynthesis stimulation. Important clinical implications of hormonal disorders should be taken into account for patients with pulmonary hypertension.