Measurement of low-derivative surface lenses by two-laser holography with Bi12TiO20 crystals

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Bounds on contact interactions from LEP1 data and high-Q2 HERA events

A contact four-fermion interaction between light quarks and electrons has been evoked as a possible explanation for the excess of events observed by HERA at high-Q2. We explore the 1-loop effects of such interaction in Γ(Z0 → e+e-) measured at LEP and impose strong bounds on the lower limit of the effective scale. Our results are able to discard some of the contact interactions as possible explanation for the HERA events. © 1997 Elsevier Science B.V.

Constraints on electroweak contact interactions from LEP and tevatron data

A complete set of dimension-six effective contact interactions involving Higgs, gauge bosons and quarks is studied. Limits on the coefficients of these new operators are obtained from the experimental values of the Z and W gauge bosons widths.

Can four-fermion contact interactions at one-loop explain the new atomic parity violation results?

We investigate the possibility that four-fermion contact interactions give rise to the observed deviation from the standard model prediction for the weak charge of cesium, through one-loop contributions. We show that the presence of loops involving the third generation quarks can explain such a deviation.

The influence of the flexibility of the chair seat on pressure peak and distribution of the contact area in individuals with cerebral palsy during the execution of a task

This study aimed to determine the influence of flexibility of the chair seat surface on the pressure peak and on the contact area during the execution of a task of handling an object on the seated position by individuals with spastic cerebral palsy. Ten individuals of both genders with diagnosis of spastic cerebral palsy, who had some control to voluntarily move the body and the upper limbs, participated in this study. Quantification of data was carried out in two experimental situations: (1) execution of a task of fitting with upper limbs, and with the individual placed on an adapted canvas seat; (2) execution of a task of fitting with the participant positioned on an adapted wooden seat. Data obtained were submitted to a non-parametric and descriptive statistical analysis using the Wilcoxon test. Results indicated that the use of canvas seat increased the contact area and decreased the pressure peak and the medio-lateral displacement of centre pressure on the seated posture. © 2011 Informa UK, Ltd.

On the undamped free vibration of a mass interacting with a Hertzian contact stiffness

Three methods are used to determine the natural frequency of undamped free vibration of a mass interacting with a Hertzian contact stiffness. The exact value is determined using the first integral of motion. The harmonic balance method is used on a transformed equation for an approximate solution, and the multiple scales method is used on an approximate equation. The maximum initial displacement avoiding contact loss is also determined, and the corresponding exact natural frequency is also obtained analytically. The methods are evaluated by studying the free vibration of an elastic sphere on a flat rigid surface. © 2011 Elsevier Ltd © 2011 Elsevier Ltd. All rights reserved.

Effect of disinfection and accelerated ageing on dimensional stability and detail reproduction of a facial silicone with nanoparticles

The aim of the present study was to evaluate the effect of disinfection and accelerated ageing on the dimensional stability and detail reproduction of a facial silicone with different types of nanoparticle. A total of 60 specimens were fabricated with Silastic MDX 4-4210 silicone and they were divided into three groups: colourless and pigmented with nanoparticles (make-up powder and ceramic powder). Half of the specimens of each group were disinfected with Efferdent tablets and half with neutral soap for 60 days. Afterwards, all specimens were subjected to accelerated ageing. Both dimensional stability and detail reproduction tests were performed after specimen fabrication (initial period), after chemical disinfection, and after accelerated ageing periods (252, 504 and 1008 hours). The dimensional stability test was conducted using AutoCAD software, while detail reproduction was analysed using a stereoscope magnifying glass. Dimensional stability values were statistically evaluated by analysis of variance (ANOVA) followed by Tukey's test (p < 0.01). Detail reproduction results were compared using a score. Chemical disinfection and also accelerated ageing affected the dimensional stability of the facial silicone with statistically significant results. The silicone's detail reproduction was not affected by these two factors regardless of nanoparticle type, disinfection and accelerated ageing. © 2012 Informa UK, Ltd.

A hydrogel scaffold that maintains viability and supports differentiation of dental pulp stem cells

Objectives: The clinical translation of stem cell-based Regenerative Endodontics demands further development of suitable injectable scaffolds. Puramatrix™ is a defined, self-assembling peptide hydrogel which instantaneously polymerizes under normal physiological conditions. Here, we assessed the compatibility of Puramatrix™ with dental pulp stem cell (DPSC) growth and differentiation. Methods: DPSC cells were grown in 0.05-0.25% Puramatrix™. Cell viability was measured colorimetrically using the WST-1 assay. Cell morphology was observed in 3D modeling using confocal microscopy. In addition, we used the human tooth slice model with Puramatrix™ to verify DPSC differentiation into odontoblast-like cells, as measured by expression of DSPP and DMP-1. Results: DPSC survived and proliferated in Puramatrix™ for at least three weeks in culture. Confocal microscopy revealed that cells seeded in Puramatrix™ presented morphological features of healthy cells, and some cells exhibited cytoplasmic elongations. Notably, after 21 days in tooth slices containing Puramatrix™, DPSC cells expressed DMP-1 and DSPP, putative markers of odontoblastic differentiation. Significance: Collectively, these data suggest that self-assembling peptide hydrogels might be useful injectable scaffolds for stem cell-based Regenerative Endodontics. © 2012 Academy of Dental Materials.

Evaluation of skin hydration after exposition to the aqueous and hydroalcoholic bases and silicone emulsion

Several dermocosmetic bases even without active substances, can increase the cutaneous hydration, resulting in a beneficial effect to the skin. The evidence and interpretation of possible hydration effect of formulations in the skin can be carried through by means of histopathological and histomorphometrical evaluation, a time that allows the analysis of the epithelial tissue, of dermis and also of the cellular characteristics. The objective of this research was to evaluate the skin hydration after exposition to the aqueous and hydroalcoholic bases and silicone emulsion. Swines had areas submitted to treatments during 15 days with three different formulations (F1 - aqueous gel, F2 - hydroalcoholic gel and F3 - silicone emulsion). By means of histometric and histopathological techniques were gotten the thickness of the epidermis and stratum corneum. Comparison of means was done using ANOVA followed by the Tukey test. The F1 provoked significant increase in the thickness of the epidermis. The formulaton F2 provoked significant reduction in the thickness of the epidermis and stratum corneum. F3 not presented significant difference in this structures. According to the study, the type of base chosen intervenes with the skin hydration.

Search for contact interactions in μ+μ- events in pp collisions at √s=7 TeV

Results are reported from a search for the effects of contact interactions using events with a high-mass, oppositely charged muon pair. The events are collected in proton-proton collisions at √s=7 TeV using the Compact Muon Solenoid detector at the Large Hadron Collider. The data sample corresponds to an integrated luminosity of 5.3 fb-1. The observed dimuon mass spectrum is consistent with that expected from the standard model. The data are interpreted in the context of a quark- and muon-compositeness model with a left-handed isoscalar current and an energy scale parameter Λ. The 95% confidence level lower limit on Λ is 9.5 TeV under the assumption of destructive interference between the standard model and contact-interaction amplitudes. For constructive interference, the limit is 13.1 TeV. These limits are comparable to the most stringent ones reported to date. © 2013 CERN. Published by the American Physical Society.

Search for contact interactions using the inclusive jet pT spectrum in pp collisions at √s=7 TeV

Results are reported of a search for a deviation in the jet production cross section from the prediction of perturbative quantum chromodynamics at next-to-leading order. The search is conducted using a 7 TeV proton-proton data sample corresponding to an integrated luminosity of 5.0 fb-1, collected with the Compact Muon Solenoid detector at the Large Hadron Collider. A deviation could arise from interactions characterized by a mass scale Λ too high to be probed directly at the LHC. Such phenomena can be modeled as contact interactions. No evidence of a deviation is found. Using the CL s criterion, lower limits are set on Λ of 9.9 TeV and 14.3 TeV at 95% confidence level for models with destructive and constructive interference, respectively. Limits obtained with a Bayesian method are also reported. © 2013 CERN.

Deproteinized bovine bone mineral particles and osseointegration of implants without primary bone contact: An experimental study in dogs

Objectives: To evaluate the influence on osseointegration of Deproteinized bovine bone mineral (DBBM) particles used to fill defects of at least 1 mm around implants having no primary contact with bone. Material and methods: Premolars and first molars were extracted bilaterally from the mandible of six Labrador dogs. After 3 months of healing, mucoperiosteal full-thickness flaps were elevated, and one recipient site was prepared in the molar region of each hemi-mandible to place implants. These were installed with a deliberate circumferential and periapical space to the bone walls of 1.2 mm. All implants were stabilized with passive fixation plates to maintain the implants in situ and without any contact with the implant bed. The control sites were left to be filled with coagulum, while at the test sites, the residual gap was filled with DBBM. After 3 months of submerged healing, the animals were sacrificed. Ground sections were prepared and analyzed histomorphometrically. Results: Mineralized bone-to-implant contact was 4.0% and 3.9% for control and test sites, respectively. The width of the residual defects was 0.48 mm and 0.88 mm at the control and test sites, respectively. The percentage of implant surface covered by a layer of dense connective tissue of 0.12 mm of width on average was 84.9% and 88.5% at the control and test sites, respectively. Conclusion: A minor and not predictable degree of contact or distance osteogenesis was obtained on the implant surface when primary contact of the implant surface with the implant bed had deliberately been avoided. DBBM grafting of the artificial gap did not favor osseointegration. Neither did it enhance the ability to bridge the gap with newly formed bone in an artificial defect wider than 1 mm. © 2013 John Wiley & Sons A/S.

Evaluation of the biocompatibility of silicone gel implants - histomorphometric study

Breast implants are medical devices that are used to augment breast size or to reconstruct the breast following mastectomy or to correct a congenital abnormality. Breast implants consist of a silicone outer shell and a filler (most commonly silicone gel or saline). Approximately 5 to 10 million women worldwide have breast implants. Histomorphometric study to evaluate the biological tissue compatibility of silicone implants suitable for plastic surgery and the adverse effects and risks of this material. Thirty Wistar white rats received subcutaneous implants and the revestiment of silicone gel Silimed ®®, and randomized into six groups of five animals each, according to the type of implanted material and the time of sacrifice. Eight areas of 60.11mm2 corresponding to the obtained surgical pieces were analyzed, counting mesenchymal cells, eosinophils, and foreign body giant cells, observing an acceptable biocompatibility in all implants, for subsequent statistical analysis by Tukey test. Silicone gel showed inflammation slightly greater than for other groups, with tissue reactions varying from light to moderate, whose result was the formation of a fibrous capsule around the material, recognized by the organism as a foreign body. Despite frequent local complications and adverse outcomes, this research showed that the silicone and top layer presented an acceptable chronic inflammatory reaction, which did not significantly differ from the control group. In general, it is possible to affirm that silicone gel had acceptable levels of biocompatibility, confirmed the rare presence of foreign body giant cells, and when of the rupture, formed a fibrous capsule around the material, separating the material of the organism. © AVICENA 2013.

Previous contact with Strongyloides venezuelensis contributed to prevent insulitis in MLD-STZ diabetes

Epidemiological and experimental studies support the idea that helminth infections can induce a protective effect against the development of autoimmune and allergic diseases. In this study we characterized the immune response induced by Strongyloides venezuelensis infection in C57BL/6 mice and then evaluated the effect of a previous contact with this helminth in the outcome of type 1 diabetes. Animals were initially infected with 2000 L3 larvae from S. venezuelensis and euthanized 22. days later. An acute phase, identified by a high amount of eggs per gram of feces, was established between days 7 and 9 post-infection. Recovery from infection was associated with a Th2 polarized response characterized by a significant level of serum IgG1 specific antibodies and also a significant production of IL-5 and IL-10 by spleen cells stimulated with S. venezuelensis soluble antigen. Immunization with soluble S. venezuelensis antigen associated with complete Freund's adjuvant followed by infection with S. venezuelensis protected mice from diabetes development induced by streptozotocin. Protection was characterized by a higher body weight gain, lower glycemic levels, much less severe insulitis and preserved insulin production. Together, these results indicate that S. venezuelensis contributed to protect C57BL/6 mice against experimental diabetes induced by streptozotocin. © 2013 Elsevier Inc.

Surface Roughness of Acrylic and Silicone-Based Soft Liners: In Vivo Study in a Rat Model

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)