Effectiveness of Screw Surface Coating on the Stability of Zirconia Abutments After Cyclic Loading

Purpose: Different surface treatments have been developed in attempts to prevent the loosening of abutment screws. The aim of the current study was to compare the effectiveness of titanium alloy screws with tungsten-doped diamond-like carbon (W-DLC) coating and uncoated screws in providing stability to zirconia (ZrO2) ceramic abutments after cyclic loading. Materials and Methods: Twenty prefabricated ZrO2 ceramic abutments on their respective external-hex implants were divided into two groups of equal size according to the type of screw used: uncoated titanium alloy screw (Ti) or titanium alloy screw with W-DLC coating (W-DLC/Ti). The removal torque value (preload) of the abutment screw was measured before and after loading. Cyclic loading between 11 and 211 N was applied at an angle of 30 degrees to the long axis of the implants at a frequency of 15 Hz. A target of 0.5 x 10(6) cycles was defined. Group means were calculated and compared using analysis of variance and the F test (alpha=.05). Results: Before cyclic loading, the preload for Ti screws was significantly higher than that for W-DLC/Ti screws (P=.021). After cyclic loading, there was no significant difference between them (P=.499). Conclusions: Under the studied conditions, it can be concluded that, after cyclic loading, both abutment screws presented a significant reduction in the mean retained preload and similar effectiveness in maintaining preload. INT J ORAL MAXILLOFAC IMPLANTS 2012;27:1061-1067

Markiana nigripinnis (Perugia, 1891) as a putative member of the subfamily Stevardiinae (Characiformes: Characidae): spermatic evidence

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

A new species of the Rhinella margaritifera group (Anura: Bufonidae) from Brazilian Pantanal

We describe adult morphology, advertisement call and some natural history traits of a new species of toad from the Pantanal, western Brazil. Rhinella paraguayensis sp. nov. belongs to the Rhinella margaritifera group, and is characterized by medium size, snout rounded in dorsal view, with a vertical apical ridge, supraorbital crests weakly developed, parietal crest not well developed, postorbital crest prominent, presence of a dorsolateral line of tubercles, tympanum evident, bony protrusions at angle of jaws, absence of vertebral apophyses and of projections on upper eyelids, and parotoid glands small. The new species is distinguished from other species of the group by geographic distribution and by the use of floating mats of vegetation as reproductive site.

Wettability of Aqueous Rhamnolipids Solutions Produced by Pseudomonas aeruginosa LBI

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

Spectral analysis of the electromyograph of the erector spinae muscle before and after a dynamic manual load-lifting test

The aim of the present study was to assess the spectral behavior of the erector spinae muscle during isometric contractions performed before and after a dynamic manual load-lifting test carried out by the trunk in order to determine the capacity of muscle to perform this task. Nine healthy female students participated in the experiment. Their average age, height, and body mass (± SD) were 20 ± 1 years, 1.6 ± 0.03 m, and 53 ± 4 kg, respectively. The development of muscle fatigue was assessed by spectral analysis (median frequency) and root mean square with time. The test consisted of repeated bending movements from the trunk, starting from a 45º angle of flexion, with the application of approximately 15, 25 and 50% of maximum individual load, to the stand up position. The protocol used proved to be more reliable with loads exceeding 50% of the maximum for the identification of muscle fatigue by electromyography as a function of time. Most of the volunteers showed an increase in root mean square versus time on both the right (N = 7) and the left (N = 6) side, indicating a tendency to become fatigued. With respect to the changes in median frequency of the electromyographic signal, the loads used in this study had no significant effect on either the right or the left side of the erector spinae muscle at this frequency, suggesting that a higher amount and percentage of loads would produce more substantial results in the study of isotonic contractions.

Influence of acute pancreatitis on the in vitro responsiveness of rat mesenteric and pulmonary arteries

Background: Acute pancreatitis is an inflammatory disease characterized by local tissue injury and systemic inflammatory response leading to massive nitric oxide (NO) production and haemodynamic disturbances. Therefore, the aim of this work was to evaluate the vascular reactivity of pulmonary and mesenteric artery rings from rats submitted to experimental pancreatitis.Male Wistar rats were divided into three groups: saline (SAL); tauracholate (TAU) and phospholipase A(2) (PLA(2)). Pancreatitis was induced by administration of TAU or PLA(2) from Naja mocambique mocambique into the common bile duct of rats, and after 4 h of duct injection the animals were sacrificed. Concentration-response curves to acetylcholine (ACh), sodium nitroprusside (SNP) and phenylephrine (PHE) in isolated mesenteric and pulmonary arteries were obtained. Potency (pEC(50)) and maximal responses (E(MAX)) were determined. Blood samples were collected for biochemical analysis.Results: In mesenteric rings, the potency for ACh was significantly decreased from animals treated with TAU (about 4.2-fold) or PLA(2) (about 6.9-fold) compared to saline group without changes in the maximal responses. Neither pEC(50) nor E(MAX) values for Ach were altered in pulmonary rings in any group. Similarly, the pEC(50) and the E(MAX) values for SNP were not changed in both preparations in any group. The potency for PHE was significantly decreased in rat mesenteric and pulmonary rings from TAU group compared to SAL group (about 2.2- and 2.69-fold, for mesenteric and pulmonary rings, respectively). No changes were seen in the E(MAX) for PHE. The nitrite/nitrate (NO(x)(-)) levels were markedly increased in animals submitted to acute pancreatitis as compared to SAL group, approximately 76 and 68% in TAU and PLA(2) protocol, respectively.Conclusion: Acute pancreatitis provoked deleterious effects in endothelium-dependent relaxing response for ACh in mesenteric rings that were strongly associated with high plasma NO(x)(-) levels as consequence of intense inflammatory responses. Furthermore, the subsensitivity of contractile response to PHE in both mesenteric and pulmonary rings might be due to the complications of this pathological condition in the early stage of pancreatitis.

Cardiorespiratory responses to hypoxia in the African catfish, Clarias gariepinus (Burchell 1822), an air-breathing fish

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

Short-term stromal alterations in the rat ventral prostate following alloxan-induced diabetes and the influence of insulin replacement

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The Anatomy of the Thoracic Spinal Canal Investigated with Magnetic Resonance Imaging

BACKGROUND: We investigated, with magnetic resonance imaging, the distance of the dura mater to the spinal cord in patients without spinal or medullar disease at the 2nd, 5th, and 10th thoracic segments.METHODS: Fifty patients in the supine position underwent magnetic resonance imaging. Medial sagittal slices of the 2nd, 5th, and 10th thoracic segments were measured for the relative distances using the 1.5-T superconducting system (Gyroscan Intera, Philips Medical Systems, Best, the Netherlands). In 10 patients, the angles relative to the tangent at the insertion point on the skin were measured.RESULTS: The posterior dural-spinal cord distance is significantly greater at the midthoracic region (5th thoracic = 5.8 +/- 0.8 mm) than at the upper (2nd thoracic = 3.9 +/- 0.8 mm) and lower thoracic levels (10th thoracic = 4.1 +/- 1.0 mm) (P < 0.015). There were no differences between interspaces T2 and 110. There was no correlation between age and the measured distance between the dura mater and the spinal cord. The entry angle of the needle at T2 was 9.0 degrees +/- 2.5 degrees; at T5, 45.0 degrees +/- 7.4 degrees; and at T10, 9.50 degrees +/- 4.2 degrees.CONCLUSIONS: This study demonstrated that there is greater depth of the posterior subarachnoid space at the T2, T5, and T10 levels. The greater distance was found at T5. (Anesth Analg 2010;110:1494-5)

Sources of errors in the quantitative analysis of food carotenoids by HPLC

Several factors render carotenoid determination inherently difficult. Thus, in spite of advances in analytical instrumentation, discrepancies in quantitative results on carotenoids can be encountered in the international literature. A good part of the errors comes from the pre-chromatographic steps such as sampling scheme that does not yield samples representative of the food lots under investigation; sample preparation which does not maintain representativity and guarantee homogeneity of the analytical sample; incomplete extraction; physical losses of carotenoids during the various steps, especially during partition or washing and by adsorption to glass walls of containers; isomerization and oxidation of carotenoids during analysis. on the otherhand, although currently considered the method of choice for carotenoids, high performance liquid chromatography (HPLC) is subject to various sources of errors, such as: incompatibility of the injection solvent and the mobile phase, resulting in distorted or split peaks; erroneous identification; unavailability, impurity and instability of carotenoid standards; quantification of highly overlapping peaks; low recovery from the HPLC column; errors in the preparation of standard solutions and in the calibration procedure; calculation errors. Illustrations of the possible errors in the quantification of carotenoids by HPLC are presented.

Burrowing behavior of Dermatonotus muelleri (Anura, Microhylidae) with reference to the origin of the burrowing behavior of Anura

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of mechanical cycling on the bonding of zirconia and fiber posts to human root dentin

Purpose: To evaluate the effect of cyclical mechanical loading on the bond strength of a fiber and a zirconia post bonded to root dentin.Materials and Methods: Forty single-rooted human teeth (maxillary incisors and canines) were sectioned, and the root canals were prepared at 12 mm. Twenty randomly seleced specimens received a quartz fiber post (FRC) (D.T. Light-Post) and 20 others received a zirconia post (ZR) (Cosmopost). The posts were resin luted (All Bond 2 + resin cement Duo-link) and each specimen was embedded in epoxy resin inside a PVC cylinder. Ten specimens with FRC post and 10 specimens with ZR post were submitted to fatigue testing (2,000,000 cycles; load: 50 N; angle of 45 degrees; frequency: 8 Hz), while the other 20 specimens were not fatigued. Thus, 4 groups were formed: G1: FRC+O cycles; G2: FRC+2,000,000 cycles; G3: ZR+O cycles; G4: ZR+2,000,000 cycles. Later, the specimens were cut perpendicular to their long axis to form 2-mm-thick disk-shaped samples (4 sections/specimen), which were submitted to the push-out test (1 mm/min). The mean bond strength values (MPa) were calculated for each tooth (n = 10) and data were submitted to statistical analysis (alpha = 0.05).Results: Two-way ANOVA revealed that the bond strength was significantly affected by mechanical cycling (p = 0.0014) and root post (p = 0.0325). The interaction was also statistically significant (p = 0.0010). Tukey's test showed that the mechanical cycling did not affect the bonding of FRC to root dentin, while fatigue impaired the bonding of zirconium to root dentin.Conclusion: (1) the bond strength of the FRC post to root dentin was not reduced after fatigue testing, whereas the bonding of the zirconia post was significantly affected by the fatigue. (2) Cyclical mechanical loading appears to damage the bond strength of the rigid post only.

Confocal Laser Microscopic Analysis of Biofilm on Newer Feldspar Ceramic

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

Resistance to compression of weakened roots subjected to different root reconstruction protocols

Objective: This study evaluated, in vitro, the fracture resistance of human non-vital teeth restored with different reconstruction protocols. Material and methods: Forty human anterior roots of similar shape and dimensions were assigned to four groups (n=10), according to the root reconstruction protocol: Group I (control): non-weakened roots with glass fiber post; Group II: roots with composite resin by incremental technique and glass fiber post; Group III: roots with accessory glass fiber posts and glass fiber post; and Group IV: roots with anatomic glass fiber post technique. Following post cementation and core reconstruction, the roots were embedded in chemically activated acrylic resin and submitted to fracture resistance testing, with a compressive load at an angle of 45 degrees in relation to the long axis of the root at a speed of 0.5 mm/min until fracture. All data were statistically analyzed with bilateral Dunnett's test (alpha=0.05). Results: Group I presented higher mean values of fracture resistance when compared with the three experimental groups, which, in turn, presented similar resistance to fracture among each other. None of the techniques of root reconstruction with intraradicular posts improved root strength, and the incremental technique was suggested as being the most recommendable, since the type of fracture that occurred allowed the remaining dental structure to be repaired. Conclusion: The results of this in vitro study suggest that the healthy remaining radicular dentin is more important to increase fracture resistance than the root reconstruction protocol.

Tree-level violation of the equivalence principle

Massive particles of spin 0 and 1 violate the equivalence principle (EP) at the tree level. on the other hand, if these particles are massless, they agree with the EP, which leads us to conjecture that from a semiclassical viewpoint massless particles, no matter what their spin, obey the EP. General relativity predicts a deflection angle of 2.63' for a nonrelativistic spinless massive boson passing close to the Sun, while for a massive vectorial boson of spin 1 the corresponding deflection is 2.62'.