Corrosion Kinetics And Topography Analysis Of Ti-6al-4v Alloy Subjected To Different Mouthwash Solutions.

This study evaluated the corrosion kinetics and surface topography of Ti-6Al-4V alloy exposed to mouthwash solutions (0.12% chlorhexidine digluconate, 0.053% cetylpyridinium chloride and 3% hydrogen peroxide) compared to artificial saliva (pH6.5) (control). Twenty Ti-6Al-4V alloy disks were used and divided into 4 groups (n=5). For the electrochemical assay, standard tests as open circuit potential and electrochemical impedance spectroscopy (EIS) were applied at baseline, 7 and 14days after immersion in the solutions. Scanning electron microscopy, atomic force microscopy and profilometry (average roughness - Ra) were used for surface characterization. Total weight loss of disks was calculated. Data were analyzed by ANOVA and Bonferroni's test (α=0.05). Hydrogen peroxide generated the lowest polarization resistance (Rp) values for all periods (P<0.05). For the capacitance (Cdl), similar results were observed among groups at baseline (P=0.098). For the 7 and 14-day periods, hydrogen peroxide promoted the highest Cdl values (P<0.0001). Hydrogen peroxide promoted expressive superficial changes and greater Ra values than the others (P<0.0001). It could be concluded that solutions containing cetylpyridinium chloride and chlorhexidine digluconate might be the mouthwashes of choice during the post-operatory period of dental implants. However, hydrogen peroxide is counter-indicated in these situations. Further studies evaluating the dynamics of these solutions (tribocorrosion) and immersing the disks in daily cycles (two or three times a day) to mimic a clinical situation closest to the application of mouthwashes in the oral cavity are warranted to prove our results.

Observation Of D0 Meson Nuclear Modifications In Au+au Collisions At Sqrt[s(nn)] = 200 Gev.

We report the first measurement of charmed-hadron (D(0)) production via the hadronic decay channel (D(0) → K(-) + π(+)) in Au+Au collisions at sqrt[s(NN)] = 200 GeV with the STAR experiment. The charm production cross section per nucleon-nucleon collision at midrapidity scales with the number of binary collisions, N(bin), from p+p to central Au+Au collisions. The D(0) meson yields in central Au + Au collisions are strongly suppressed compared to those in p+p scaled by N(bin), for transverse momenta p(T) > 3 GeV/c, demonstrating significant energy loss of charm quarks in the hot and dense medium. An enhancement at intermediate p(T) is also observed. Model calculations including strong charm-medium interactions and coalescence hadronization describe our measurements.

Tissue Microarray Is A Reliable Method For Immunohistochemical Analysis Of Pleomorphic Adenoma.

To determine the most adequate number and size of tissue microarray (TMA) cores for pleomorphic adenoma immunohistochemical studies. Eighty-two pleomorphic adenoma cases were distributed in 3 TMA blocks assembled in triplicate containing 1.0-, 2.0-, and 3.0-mm cores. Immunohistochemical analysis against cytokeratin 7, Ki67, p63, and CD34 were performed and subsequently evaluated with PixelCount, nuclear, and microvessel software applications. The 1.0-mm TMA presented lower results than 2.0- and 3.0-mm TMAs versus conventional whole section slides. Possibly because of an increased amount of stromal tissue, 3.0-mm cores presented a higher microvessel density. Comparing the results obtained with one, two, and three 2.0-mm cores, there was no difference between triplicate or duplicate TMAs and a single-core TMA. Considering the possible loss of cylinders during immunohistochemical reactions, 2.0-mm TMAs in duplicate are a more reliable approach for pleomorphic adenoma immunohistochemical study.

The Neuromuscular Activity Of Bothriopsis Bilineata Smaragdina (forest Viper) Venom And Its Toxin Bbil-tx (asp49 Phospholipase A2) On Isolated Mouse Nerve-muscle Preparations.

The presynaptic action of Bothriopsis bilineata smaragdina (forest viper) venom and Bbil-TX, an Asp49 PLA2 from this venom, was examined in detail in mouse phrenic nerve-muscle (PND) preparations in vitro and in a neuroblastoma cell line (SK-N-SH) in order to gain a better insight into the mechanism of action of the venom and associated Asp49 PLA2. In low Ca(2+) solution, venom (3μg/ml) caused a quadriphasic response in PND twitch height whilst at 10μg/ml the venom additionally induced an abrupt and marked initial contracture followed by neuromuscular facilitation, rhythmic oscillations of nerve-evoked twitches, alterations in baseline and progressive blockade. The venom slowed the relaxation phase of muscle twitches. In low Ca(2+), Bbil-TX [210nM (3μg/ml)] caused a progressive increase in PND twitch amplitude but no change in the decay time constant. Venom (10μg/ml) and Bbil-TX (210nM) caused minor changes in the compound action potential (CAP) amplitude recorded from sciatic nerve preparations, with no significant effect on rise time and latency; tetrodotoxin (3.1nM) blocked the CAP at the end of the experiments. In mouse triangularis sterni nerve-muscle (TSn-m) preparations, venom (10μg/ml) and Bbil-TX (210nM) significantly reduced the perineural waveform associated with the outward K(+) current while the amplitude of the inward Na(+) current was not significantly affected. Bbil-TX (210nM) caused a progressive increase in the quantal content of TSn-m preparations maintained in low Ca(2+) solution. Venom (3μg/ml) and toxin (210nM) increased the calcium fluorescence in SK-N-SH neuroblastoma cells loaded with Fluo3 AM and maintained in low or normal Ca(2+) solution. In normal Ca(2+), the increase in fluorescence amplitude was accompanied by irregular and frequent calcium transients. In TSn-m preparations loaded with Fluo4 AM, venom (10μg/ml) caused an immediate increase in intracellular Ca(2+) followed by oscillations in fluorescence and muscle contracture; Bbil-TX did not change the calcium fluorescence in TSn-m preparations. Immunohistochemical analysis of toxin-treated PND preparations revealed labeling of junctional ACh receptors but a loss of the presynaptic proteins synaptophysin and SNAP25. Together, these data confirm the presynaptic action of Bbil-TX and show that it involves modulation of K(+) channel activity and presynaptic protein expression.

[comparative Study Between Fast And Slow Induction Of Propofol Given By Target-controlled Infusion: Expected Propofol Concentration At The Effect Site. Randomized Controlled Trial].

studies have shown that rate of propofol infusion may influence the predicted propofol concentration at the effect site (Es). The aim of this study was to evaluate the Es predicted by the Marsh pharmacokinetic model (ke0 0.26min(-1)) in loss of consciousness during fast or slow induction. the study included 28 patients randomly divided into two equal groups. In slow induction group (S), target-controlled infusion (TCI) of propofol with plasma, Marsh pharmacokinetic model (ke0 0.26min(-1)) with target concentration (Tc) at 2.0-μg.mL(-1) were administered. When the predicted propofol concentration at the effect site (Es) reached half of Es value, Es was increased to previous Es + 1μg.mL(-1), successively, until loss of consciousness. In rapid induction group (R), patients were induced with TCI of propofol with plasma (6.0μg.ml(-1)) at Es, and waited until loss of consciousness. in rapid induction group, Tc for loss of consciousness was significantly lower compared to slow induction group (1.67±0.76 and 2.50±0.56μg.mL(-1), respectively, p=0.004). the predicted propofol concentration at the effect site for loss of consciousness is different for rapid induction and slow induction, even with the same pharmacokinetic model of propofol and the same balance constant between plasma and effect site.

Reduction Of Oxidative Damage And Inflammatory Response In The Diaphragm Muscle Of Mdx Mice Using Iron Chelator Deferoxamine.

Oxidative stress and inflammatory processes strongly contribute to pathogenesis in Duchenne muscular dystrophy (DMD). Based on evidence that excess iron may increase oxidative stress and contribute to the inflammatory response, we investigated whether deferoxamine (DFX), a potent iron chelating agent, reduces oxidative stress and inflammation in the diaphragm (DIA) muscle of mdx mice (an experimental model of DMD). Fourteen-day-old mdx mice received daily intraperitoneal injections of DFX at a dose of 150 mg/kg body weight, diluted in saline, for 14 days. C57BL/10 and control mdx mice received daily intraperitoneal injections of saline only, for 14 days. Grip strength was evaluated as a functional measure, and blood samples were collected for biochemical assessment of muscle fiber degeneration. In addition, the DIA muscle was removed and processed for histopathology and Western blotting analysis. In mdx mice, DFX reduced muscle damage and loss of muscle strength. DFX treatment also resulted in a significant reduction of dystrophic inflammatory processes, as indicated by decreases in the inflammatory area and in NF-κB levels. DFX significantly decreased oxidative damage, as shown by lower levels of 4-hydroxynonenal and a reduction in dihydroethidium staining in the DIA muscle of mdx mice. The results of the present study suggest that DFX may be useful in therapeutic strategies to ameliorate dystrophic muscle pathology, possibly via mechanisms involving oxidative and inflammatory pathways.

Qualidade de vida e composição corporal : características do envelhecimento bem sucedido = Quality of life and body composition : characteristics of successful aging

Universidade Estadual de Campinas . Faculdade de Educação Física

Comparison of periodontal parameters in individuals with syndromic craniosynostosis

Craniosynostosis syndromes are characterized by premature closure of one or more cranial sutures, associated with other malformations, the most frequent of which are the Crouzon and Apert syndromes. Few studies in the literature have addressed the oral health of these individuals. The purpose of this study was to compare the periodontal status of individuals with Apert, Crouzon, Pfeiffer and Saethre-Chotzen syndromes before toothbrushing and compare the efficiency of plaque removal before and after mechanical toothbrushing. The probing depth, plaque index (according to Löe and O'Leary), clinical attachment level, gingival index (according to Silness and Löe) and amount of keratinized mucosa were evaluated before toothbrushing, and the O'Leary plaque index was assessed before and immediately after toothbrushing, on the same day, in 27 individuals aged 11 to 36 years. There was statistically significant difference in the mean probing depth and clinical attachment level among regions (p=0.00; p=0.01, respectively). The gingival index did not reveal statistically significant differences. With regard to the plaque index, the left region exhibited higher plaque index values than the right and anterior regions. No significant results were found in the analysis of keratinized mucosa. Comparison of the O'Leary plaque index before and after toothbrushing revealed statistically significant difference for all syndromes except for the Pfeiffer syndrome (p<0.05). In conclusion, there was no difference in the periodontal status among individuals with syndromic craniosynostosis. The posterior region was more affected than the anterior region as to the presence of plaque, loss of insertion and probing depth. Individuals with Pfeiffer syndrome exhibited greater toothbrushing efficiency than individuals with the other craniosynostosis syndromes.

Evaluation of screw loosening on new abutment screws and after successive tightening

This study evaluated the loss of the torque applied after use of new screws and after successive tightening. Four infrastructures (IE), using UCLA castable abutment type, were cast in cobalt-chromium alloy and new abutment screws (G1) were used in a first moment. Subsequently, the same abutment screws were used a second time (G2) and more than two times (G3). The values of the torques applied and detorques were measured with a digital torque wrench to obtain the values of initial tightening loss (%). Data were analyzed by ANOVA and Tukey's test (?=0.05). Significant differences were observed between the G1 (50.71% ± 11.36) and G2 (24.01% ± 3.33) (p=0.000) and between G1 (50.71% ± 11.36) and G3 (25.60% ± 4.64) (p=0.000). There was no significant difference between G2 and G3 (p=0.774). Within the limitations of the study, it may be concluded that the percentage of the initial torque loss is lower when screws that already suffered the application of an initial torque were used, remaining stable after application of successive torques.

Bone quality associated with daily intake of coffee: a biochemical, radiographic and histometric study

Caffeine induces loss of calcium and influences the normal development of bone. This study investigated the effects of coffee on bone metabolism in rats by biochemical measurement of calcium, bone densitometry and histometry. Male rats, born of female treated daily with coffee and with coffee intake since born, were anesthetized, subjected to extraction of the upper right incisor, and sacrificed 7, 21 and 42 days after surgery. Blood and urine samples were taken, and their maxilla radiographed and processed to obtain 5-µm-thick semi-serial sections stained with hematoxylin and eosin. The volume and bone quality were estimated using an image-analysis software. The results showed significantly greater amount of calcium in the plasma (9.40 ± 1.73 versus 9.80 ± 2.05 mg%) and urine (1.00 ± 0.50 versus 1.25 ± 0.70 mg/24 h) and significantly less amount in bone (90.0 ± 1.94 versus 86.0 ± 2.12 mg/mg bone), reduced bone mineral density (1.05 ± 0.11 versus 0.65 ± 0.15 mmAL), and lower amount of bone (76.19 ± 1.6 versus 53.41 ± 2.1 %) (ANOVA; p≤0.01) in animals treated with coffee sacrificed after 42 days. It may be concluded that coffee/caffeine intake caused serious adverse effects on calcium metabolism in rats, including increased levels of calcium in the urine and plasma, decreased bone mineral density and lower volume of bone, thus delaying the bone repair process.

Sex ratio and morphological characteristics of rufous gnateaters, Conopophaga lineata (Aves, Passeriformes) in Atlantic forest fragments

Unequal sex ratios lead to the loss of genetic variability, decreasing the viability of populations in the long term. Anthropogenic activities often disturb the natural habitats and can cause alterations in sex ratio and morphological characteristics of several species. Forest fragmentation is a major conservation concern, so that understanding its effects in natural populations is essential. In this study, we evaluated the sex ratio and the morphological characteristics of Rufous Gnateaters (Conopophaga lineata (Wied, 1831)) in small and large forest fragments in Minas Gerais, Brazil. Birds (n = 89) were sexed by plumage characteristics and molecular markers. The molecular analysis showed that plumage is not a totally reliable method for sexing Rufous Gnateaters. We observed that sex ratio did not differ between large and small forest fragments, but birds in small fragments had larger wings and tarsus. Wing and tarsus changes may affect the movement ability of individuals within and among forest fragments. In conclusion, Rufous Gnateaters have been able to survive in both small and large Atlantic rain forest fragments without altering their sex ratio, but morphological changes can be prejudicial to their long term survival.

Characterization of oil shale residue and rejects from irati formation by electron paramagnetic resonance

In this study, sedimentary organic matter of oil shale rejects, calschist, shale fine and the so called retorted shale from Irati formation was characterized. EPR was used to analyse the samples regarding loss of signal in g = 2.003 associated to the organic free radical with the calcined samples and washing with hydrogen peroxide. The radical signal was detected in all samples, however, for the calschist and shale fine samples another signal was identified at g = 2.000 which disappeared when the sample was heated at 400 ºC. Hydrogen peroxide washing was also performed and it was noted that after washing the signal appeared around g = 2.000 for all samples, including retorted shale, which might be due to the quartz E1 defect.

Characterization of aqueous silver nitrate solutions for leakage tests

OBJECTIVE: To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated. MATERIAL AND METHODS: A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled) and three brands of silver nitrate salt (Merck, Synth or Cennabras) at 0, 1, 2, 24, 48, 72, 96 and 168 h after preparation, and storage in transparent or dark bottles. Ionic silver was assayed according to the post-preparation times (2, 24, 48, 72, 96, 168 h) and concentrations (1, 5, 25, 50%) of solutions by atomic emission spectrometry. For each sample of each condition, three readings were obtained for calculating the mean value. Class V cavities were prepared with enamel margins on primary and permanent teeth and restored with the adhesive systems OptiBond FL or OptiBond SOLO Plus SE and the composite resin Filtek Z-250. After nail polish coverage, the permanent teeth were immersed in 25% or 50% AgNO3 solution and the primary teeth in 5% or 50% AgNO3 solutions for microleakage evaluation. ANOVA and the Tukey's test were used for data analyses (α=5%). RESULTS: The mean pH of the solutions ranged from neutral to alkaline (7.9±2.2 to 11.8±0.9). Mean ionic silver content differed depending on the concentration of the solution (4.75±0.5 to 293±15.3 ppm). In the microleakage test, significant difference was only observed for the adhesive system factor (p=0.000). CONCLUSIONS: Under the tested experimental conditions and based on the obtained results, it may be concluded that the aqueous AgNO3 solutions: have neutral/alkaline pH and service life of up to 168 h; the level of ionic silver is proportional to the concentration of the solution; even at 5% concentration, the solutions were capable of indicating loss of marginal seal in the composite restorations; the 3-step conventional adhesive system had better performance regarding microleakage in enamel on primary and permanent teeth.

Effect of protein intake on bone and muscle mass in the elderly

The aging process is frequently characterized by an involuntary loss of muscle (sarcopenia) and bone (osteoporosis) mass. Both chronic diseases are associated with decreased metabolic rate, increased risk of falls fracture, and, as a result, increased morbidity and loss of independence in the elderly. The quality and quantity of protein intake affects bone and muscle mass in several ways and there is evidence that increased essential amino acid or protein availability can enhance muscle protein synthesis and anabolism, as well as improve bone homeostasis in older subjects. A thorough evaluation of renal function is important, since renal function decreases with age. Finally, protein and calcium intake should be considered in the prevention or treatment of the chronic diseases osteoporosis and sarcopenia

Risk optimization of a steel frame communications tower subject to tornado winds

The structural engineering community in Brazil faces new challenges with the recent occurrence of high intensity tornados. Satellite surveillance data shows that the area covering the south-east of Brazil, Uruguay and some of Argentina is one of the world most tornado-prone areas, second only to the infamous tornado alley in central United States. The design of structures subject to tornado winds is a typical example of decision making in the presence of uncertainty. Structural design involves finding a good balance between the competing goals of safety and economy. This paper presents a methodology to find the optimum balance between these goals in the presence of uncertainty. In this paper, reliability-based risk optimization is used to find the optimal safety coefficient that minimizes the total expected cost of a steel frame communications tower, subject to extreme storm and tornado wind loads. The technique is not new, but it is applied to a practical problem of increasing interest to Brazilian structural engineers. The problem is formulated in the partial safety factor format used in current design codes, with all additional partial factor introduced to serve as optimization variable. The expected cost of failure (or risk) is defined as the product of a. limit state exceedance probability by a limit state exceedance cost. These costs include costs of repairing, rebuilding, and paying compensation for injury and loss of life. The total expected failure cost is the sum of individual expected costs over all failure modes. The steel frame communications, tower subject of this study has become very common in Brazil due to increasing mobile phone coverage. The study shows that optimum reliability is strongly dependent on the cost (or consequences) of failure. Since failure consequences depend oil actual tower location, it turn,,; out that different optimum designs should be used in different locations. Failure consequences are also different for the different parties involved in the design, construction and operation of the tower. Hence, it is important that risk is well understood by the parties involved, so that proper contracts call be made. The investigation shows that when non-structural terms dominate design costs (e.g, in residential or office buildings) it is not too costly to over-design; this observation is in agreement with the observed practice for non-optimized structural systems. In this situation, is much easier to loose money by under-design. When by under-design. When structural material cost is a significant part of design cost (e.g. concrete dam or bridge), one is likely to lose significantmoney by over-design. In this situation, a cost-risk-benefit optimization analysis is highly recommended. Finally, the study also shows that under time-varying loads like tornados, the optimum reliability is strongly dependent on the selected design life.