Analysis of mechanical behavior of implant-supported prostheses in the anterior maxilla: analysis by speckle pattern interferometry

The use of implants to rehabilitation of total edentulous, partial edentulous or single tooth is increasing, it is due to the high rate of success that this type of treatment present. The objective of this study was to analyze the mechanical behavior of different positions of two dental implants in a rehabilitation of 4 teeth in the region of maxilla anterior. The groups studied were divided according the positioning of the implants. The Group 1: Internal Hexagonal implant in position of lateral incisors and pontic in region of central incisors; Group 2: Internal Hexagonal implant in position of central incisors and cantilever of the lateral incisors and Group3 - : Internal Hexagonal implants alternate with suspended elements. The Electronic Speckle Pattern Interferometry (ESPI) technique was selected for the mechanical evaluation of the 3 groups performance. The results are shown in interferometric phase maps representing the displacement field of the prosthetic structure.

Cell death and quantitative reduction of rests of Malassez according to age

Background and Objective: Rests of Malassez are clusters of epithelial cells that remain in the periodontal ligament throughout life. However, it has been reported that the number of these structures decreases with age, and some epithelial cells undergo apoptosis in rests of Malassez of young and adult rats. Therefore, the purpose of the present study was to investigate the incidence of epithelial cell death and the quantitative changes in the rests of Malassez in rat molars of different ages.Material and Methods: Fragments containing the upper molars of rats aged 29, 45 and 120 d were fixed, decalcified and embedded for analysis by light microscopy. In the sections stained by hematoxylin and eosin, the number of rests of Malassez and the number of nuclei of these epithelial structures were obtained. Moreover, the nuclei exhibiting typical features of cell death were also counted in each rest of Malassez. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method for detection of cell death was also carried out.Results: In all groups examined, some rests of Malassez exhibited epithelial cell nuclei with typical features of apoptosis and some of them were also TUNEL positive. From 29 to 120 d of age in rats, the quantitative analysis showed a significant decrease in the total number of rests of Malassez in the cervical, middle and furcation regions of the periodontal ligament. Moreover, a significant decrease of epithelial cell nuclei was concomitant to an increase in the frequency of cell death in the oldest rats.Conclusion: These results suggest that epithelial cell death by apoptosis may be, at least in part, responsible for the reduction in the number of rests of Malassez according to age.

Measurement of shrinkage of composite resin by laser speckle contrast analysis

The aim of this study was to evaluate the shrinkage of a microhybrid dental composite resin photo-activated by one LED with different power densities by means of speckle technique. The dental composite resin Filtek (TM) Z-250 (3M/ESPE) at color A(2) was used for the samples preparation. Uncured composite was packed in a metallic mold and irradiated during 20 s from 100 to 1000 mW cm(-2). For the photo-activation of the samples, it was used a LED prototype (Light Emission Diode) with wavelength centered at 470 nm and adjustable power density until 1 W cm(-2). The speckle patterns obtained from the bottom composite surfaces were monitored using a CCD camera without lens. The speckle field is recorded in a digital picture and stored by CCD camera as the carrier of information on the displacement of the tested surface. The calculated values were obtained for each pair of adjacent patterns and the changes in speckle contrast as a function of time were obtained from six repeated measurements. The speckle contrasts obtained from the bottom surface with 100 mW cm(-1) were smaller than those than the other power densities. The higher power densities provided the higher shrinkage.

Reduction of crotoxin-induced neuromuscular blockade by gamma radiation

A comparative study between crotoxin and gamma irradiated crotoxin was performed on the indirectly evoked twitches and tetani of sciatic nerve-extensor digitorum longus muscle of rats. Crotoxin (3 to 14 mu g/ml) decreased the amplitude of twitches and induced a slight tetanic fade, and irradiated crotoxin did not significantly affect either twitch amplitude or tetanic tension. Since gamma radiation reduced the neurotoxicity of crotoxin it may be useful for the production of anticrotalic serum. (C) 1998 Elsevier B.V. Ltd. All rights reserved.

Acceleration of Sperm Transit Time and Reduction of Sperm Reserves in the Epididymis of Rats Exposed to Sibutramine

Sibutramine is a drug globally used for the treatment of obesity. The aim of this study was to investigate male reproductive disorders caused by sibutramine in adult rats. Wistar rats were treated for 28 consecutive days (gavage) with 10 mg/kg of sibutramine. Control animals received only vehicle (dimethylsulfoxide and saline). The rats were sacrificed for evaluation of body and reproductive organ weights, sperm parameters, hormone levels (luteinizing hormone, follicle-stimulating hormone, and testosterone), testicular and epididymal histopathology, sexual behavior, fertility and in vitro contractility of the epididymal duct. Sibutramine decreased (P < .05) weights of the epididymis and ventral prostate, but not of other reproductive organs. The sperm number and transit time in the epididymal cauda were decreased (P < .001), but the daily sperm production was not altered. Moreover, morphology and sperm motility, histopathology of the testes and epididymis, sexual behavior, fertility, and serum hormone levels were not altered by the treatment. Sibutramine increased the potency of norepinephrine and, per se, increased the mechanical activity of the epididymal duct in vitro. Thus, although sibutramine in these experimental conditions did not interfere with the reproductive process of rats, it provoked acceleration of the sperm transit time and a decrease in the sperm reserves in the epididymal cauda. This alteration is probably related to the sympathomimetic effect of this drug, as shown by the in vitro assays. In humans, use of this drug might present a threat for male fertility because sperm reserves in men are naturally lower than those in rats.

Cytogenetic characterization of Eurysternus caribaeus (Coleoptera: Scarabaeidae): evidence of sex-autosome fusion and diploid number reduction prior to species dispersion

Mitotic and meiotic chromosomes of several populations of Eurysternus caribaeus (Coleoptera: Scarabaeidae) were analysed through conventional staining, C-banding, base-specific fluorochromes, silver nitrate staining and fluorescent in situ hybridization (FISH). All specimens showed 2n = 8 in their karyotypes, with a neo-XY sex system (Y is a submetacentric and X a metacentric) and three pairs of submetacentric autosomes. The analysis of constitutive heterochromatin (CH) revealed small blocks located in the centromeric region of all chromosomes which do not present positive staining under the fluorochromes CMA3 and DAPI. Silver nitrate staining revealed that the nucleolar organizer region (NORs) is associated with the sex chromosomes. The FISH technique revealed that rDNA sites in the X and Y are different in size. Data from different populations indicate that the diploid number reduction (2n = 8) observed in E. caribaeus is established and presumably has preceded the dispersion of this species. Moreover, this reduction occasioned the translocation of rDNA sites to the sex chromosomes, X and Y, an uncommon pattern in Scarabaeidae that was observed for the first time by the FISH in this work.

Evaluation of reduction in egg shedding of gastrointestinal nematodes in cattle following administration of anthelmintics

No intuito de avaliar o tempo necessário para redução dos valores de OPG visando identificar o início de atuação dos anti-helmínticos, cinco grupos de novilhos, naturalmente infectados por nematódeos gastrintestinais foram tratados com moxidectina, ivermectina, fosfato de levamisol e sulfóxido de albendazol. O levamisol promoveu redução no número de ovos de nematódeos eliminados nas fezes (R-OPG) de 97,4% 24 horas após a aplicação, a moxidectina de 98,3% após 36 horas, e o sulfóxido de albendazol de 95,9% após 36 horas. Foi registrada a presença de Cooperia spp. e Haemonchus spp. com resistência a ivermectina. A contagem de OPG realizada aos sete dias pós-tratamento apresentou resultados similares aos obtidos nas contagens realizadas 10 e 14 dias após a aplicação dos anti-helmínticos avaliados, demonstrando que o intervalo adequado entre o tratamento anti-helmíntico e o exame para verificar a redução do OPG pode ser de 7 dias.

Reduction of a native fish fauna by alien species: an example from Brazilian freshwater tropical lakes

The consequences of introducing Cichla cf. monoculus Spix & Agassiz, Astronotus ocellatus (Agassiz) and Pygocentrus nattereri Kner into lakes in the River Doce basin, Brazil, on richness, diversity and efficiency of aquatic macrophytes as natural refugia to native fishes was investigated. Samples were taken from lakes with and without alien fishes in areas with and without aquatic macrophytes. The presence of alien fishes reduced richness and diversity of the native fish community. The refugia function, which could be attributed to the clustering of aquatic macrophytes, does not exist in these lakes probably because the alien fishes exploit such habitats for reproduction. Since introductions threaten the native fish diversity of the region, studies on regional dispersion and factors that minimise the spread of alien fishes are needed.

Chromosome banding in three species of Hypsiboas (Hylidae, Hylinae), with special reference to a new case of B-chromosome in anuran frogs and to the reduction of the diploid number of 2n=24 to 2n=22 in the genus

The chromosomes of hylids Hypsiboas albopunctatus, H. raniceps, and H. crepitans from Brazil were analyzed with standard and differential staining techniques. The former species presented 2n = 22 and 2n = 23 karyotypes, the odd diploid number is due to the presence of an extra element interpreted as B chromosome. Although morphologically very similar to the small-sized chromosomes of the A complement, the B was promptly recognized, even under standard staining, on the basis of some characteristics that are usually attributed to this particular class of chromosomes. The two other species have 2n = 24, which is the chromosome number usually found in the species of Hypsiboas karyotyped so far. This means that 2n = 22 is a deviant diploid number, resulted from a structural rearrangement, altering the chromosome number of 2n = 24 to 2n = 22. Based on new chromosome data, some possibilities were evaluated for the origin of B chromosome in Hypsiboas albopunctatus, as well as the karyotypic evolution in the genus, leading to the reduction in the diploid number of 2n = 24 to 2n = 22.

Reduction of insulin signalling pathway IRS-1/IRS-2/AKT/mTOR and decrease of epithelial cell proliferation in the prostate of glucocorticoid-treated rats

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

Efficacy of Endodontic Treatment for Endotoxin Reduction in Primarily Infected Root Canals and Evaluation of Cytotoxic Effects

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

Supersymmetry flows, semi-symmetric space sine-Gordon models and the Pohlmeyer reduction

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A symmetry reduction technique for higher order Painleve systems

The symmetry reduction of higher order Painleve systems is formulated in terms of Dirac procedure. A set of canonical variables that admit Dirac reduction procedure is proposed for Hamiltonian structures governing the A(2M)((1)) and A(2M-1)((1)) Painleve systems for M = 2,3,.... (C) 2012 Elsevier B.V. All rights reserved.

Dimensional reduction of the ABJM model

We dimensionally reduce the ABJM model, obtaining a two-dimensional theory that can be thought of as a 'master action'. This encodes information about both T- and S-duality, i.e. describes fundamental (F1) and D-strings (D1) in 9 and 10 dimensions. The Higgsed theory at large VEV, (v) over tilde, and large k yields D1-brane actions in 9d and 10d, depending on which auxiliary fields are integrated out. For N = 1 there is a map to a Green-Schwarz string wrapping a nontrivial circle in C(4)/Z(k).