Effect of recasting procedure upon corrosion behavior and metallic ion release of Co-Cr-Mo dental alloy in physiological

Recasting process influence upon corrosion behavior of Co-Cr-Mo dental alloy in simulated physiological serum has been investigated using chemical and electrochemical techniques. Recast Co-Cr-Mo alloy by induction (IND) or by blowtorch (FLAME) has exhibited similar dendritic structures. Both IND and FLAME alloys have presented good corrosion resistance in physiological serum. Passivation process provides this corrosion resistance. Codissolution makes this process difficult. Passive films, formed on these alloys, have been analyzed as a dual layer consisting of an inner barrier and an outer porous layer. Passive film protective characteristics are higher in FLAME than in IND alloy. On this last alloy, the passive film is more porous due to a higher Codissolution. ©Carl Hanser Verlag, München.

Running-based anaerobic sprint test as a procedure to evaluate anaerobic power

The aim of this study was to evaluate the use of the running anaerobic sprint test (RAST) as a predictor of anaerobic capacity, compare it to the maximal accumulated oxygen deficit (MAOD) and to compare the RAST's parameters with the parameters of 30-s all-out tethered running on a treadmill. 39 (17.0±1.4 years) soccer players participated in this study. The participants underwent an incremental test, 10 submaximal efforts [50-95% of velocity correspondent to VO2MAX (vVO2MAX)] and one supramaximal effort at 110% of vVO2MAX for the determination of MAOD. Furthermore, the athletes performed the RAST. In the second stage the 30-s all-out tethered running was performed on a treadmill (30-s all-out), and compared with RAST. No significant correlation was observed between MAOD and RAST parameters. However, significant correlations were found between the power of the fifth effort (P5) of RAST with peak and mean power of 30-s all-out (r=0.73 and 0.50; p<0.05, respectively). In conclusion, the parameters from RAST do not have an association with MAOD, suggesting that this method should not be used to evaluate anaerobic capacity. Although the correlations between RAST parameters with 30-s all-out do reinforce the RAST as an evaluation method of anaerobic metabolism, such as anaerobic power.

Determinação do posicionamento ótimo de apoios em pontes

This paper presents a study to determine the optimal support positions in bridges, as well as the optimal relation between the spans of beams, aiming both the reduction and the unifirmization of the efforts in these structures. The mathematical problem is formulated in order to minimize the maximum bending moments, taking the coordinate of each internal support as design variable. To take into account possible location limitations, size constraints are also considered in the formulation. The software developed based on this study determines the efforts in each support for load shifting along the structure by the usage of the Displacement Method, and the optimization is performed with a mathematical programming technique. The structures analyzed from the computational implementation of the idealized model point to the validation and efficiency of the proposed procedure.

EMERGENT CONDITIONAL RELATIONS IN A GO/NO-GO PROCEDURE: FIGURE-GROUND AND STIMULUS-POSITION COMPOUND RELATIONS

Past research has demonstrated emergent conditional relations using a go/no-go procedure with pairs of figures displayed side-by-side on a computer screen. The present Study sought to extend applications Of this procedure. In Experiment, 1, we evaluated whether emergent conditional relations Could be demonstrated when two-component stimuli were displayed in figure-ground relationships-abstract figures displayed on backgrounds of different colors. Five normal)), capable adults participated. During training, each two-component stimulus Was presented successively. Responses emitted in the presence of some Stimulus pairs (A1B1, A2B2, A3B3, B1C1, B2C2 and B3C3) were reinforced, whereas responses emitted in the presence of other pairs (A1B2, A1B3, A2B1, A2B3, A3B1, A3B2, B1C2, B1C3, B2C1, B2C3, B3C1 and B3C2) were not. During tests, new configurations (AC and CA) were presented, thus emulating structurally the matching-to-sample tests employed in typical equivalence Studies. All participants showed emergent relations consistent with stimulus equivalence during testing. In Experiment 2, we systematically replicated the procedures with Stimulus compounds consisting Of four figures (A1, A2, C1 and C2) and two locations (left - B1 and right - 132). A,11 6 normally capable adults exhibited emergent stimulus-stimulus relations. Together, these experiments show that the go/no-go procedure is a potentially useful alternative for Studying emergent. conditional relations when matching-to-sample is procedurally cumbersome or impossible to use.

Influence of the use of Aliquat 336 in the immobilization procedure in sol-gel of lipase from Bacillus sp ITP-001

Aliquat 336, a liquid hydrophobic material, was used at different concentrations (0.5-3.0%, w/v) as an additive in the preparation of encapsulated lipase from Bacillus sp. ITP-001 on sol-gel silica matrices using tetraethoxysilane (TEOS) as the precursor. The resulting hydrophobic matrices and immobilized lipases were characterized with regard to specific surface area (BET method), adsorption-desorption isotherms, pore volume (Vp) and size (dp) by nitrogen adsorption (BJH method) and scanning electron microscopy (SEM). The catalytic activities and the corresponding coupling yields were assayed in the hydrolysis of olive oil. In comparison with pure silica matrices, the immobilization process in the presence of Aliquat 336 decreased the values for specific surface area and increased the values for pore specific volume (Vp) and mean pore diameter (dp). This behavior may be related to the partial adsorption of the enzyme on the external surface of the hydrophobic matrix as indicated by scanning electron microscopy. Aliquat 336 concentrations in the range from 0.5 to 1.5% (w/v) provided immobilized derivatives with higher coupling yields and better substrate affinity. The highest coupling yield (Y-A = 71%) was obtained for the immobilized enzyme prepared in the presence of 1.5% Aliquat which gave the following morphological properties: specific surface area = 183 m(2)/g, pore specific volume (Vp) = 0.36 cc/g and mean pore diameter (dp)= 91 angstrom. (c) 2012 Elsevier B.V. All rights reserved.

Cleft lip and palate: recommendations for dental anesthetic procedure based on anatomic evidences

Patients with cleft lip and palate usually present dental anomalies of number, shape, structure and position in the cleft area and the general dentist is frequently asked to restore or extract those teeth. Considering that several anatomic variations are expected in teeth adjacent to cleft areas and that knowledge of these variations by general dentists is required for optimal treatment, the objectives of this paper are: 1) to describe changes in the innervation pattern of anterior teeth and soft tissue caused by the presence of a cleft, 2) to describe a local anesthetic procedure in unilateral and bilateral clefts, and 3) to provide recommendations to improve anesthetic procedures in patients with cleft lip and palate. The cases of 2 patients are presented: one with complete unilateral cleft lip and palate, and the other with complete bilateral cleft lip and palate. The patients underwent local anesthesia in the cleft area in order to extract teeth with poor bone support. The modified anesthetic procedure, respecting the altered course of nerves in the cleft maxilla and soft tissue alterations at the cleft site, was accomplished successfully and the tooth extraction was performed with no pain to the patients. General dentists should be aware of the anatomic variations in nerve courses in the cleft area to offer high quality treatment to patients with cleft lip and palate.

Clinical and nutritional status in the late postoperative of pancreaticoduodenectomy. Influence of pylorus preservation procedure

PURPOSE: To evaluate the nutritional status of patients in the late postoperative period of pancreaticoduodenectomy (PD) and compare the long-term outcome according to pylorus-preserving (PPPD) or the standard technique (SPD) in which the pylorus is resected. METHODS: This prospective study was conducted twelve months prior or more in patients who had underwent PD (PD Group, n=15) and health volunteers (Control Group, n=15). At a post hoc analysis, the PD Group was divided in PPPD Subgroup (n=9) and SPD Subgroup (n=6), according to the PD techniques. Gastrointestinal complaints and nutritional status were evaluated, apart from a biochemical assessment; Student t-test or Mann-Whitney test were used. RESULTS: The patients recovered their body weight and the gastrointestinal complaints were uncommon. The PD Group showed higher energy and protein intake even though BMI was lower than in Control Group. There were no differences in laboratorial data, except for higher glycemia, serum alkaline phosfatase and C-reactive protein in PD Group. There was no difference in the various parameters evaluated when the Subgroups (PPPD and SPD) were compared. CONCLUSION: For long-term pancreaticoduodenectomy, the gastrointestinal symptoms are minimal and the patients had the clinical and nutritional status preserved, regardless of pylorus preservation.

A Bayesian nonparametric model for Taguchi's on-line quality monitoring procedure for attributes

A Bayesian nonparametric model for Taguchi's on-line quality monitoring procedure for attributes is introduced. The proposed model may accommodate the original single shift setting to the more realistic situation of gradual quality deterioration and allows the incorporation of an expert's opinion on the production process. Based on the number of inspections to be carried out until a defective item is found, the Bayesian operation for the distribution function that represents the increasing sequence of defective fractions during a cycle considering a mixture of Dirichlet processes as prior distribution is performed. Bayes estimates for relevant quantities are also obtained. (C) 2012 Elsevier B.V. All rights reserved.

The Nuss procedure made safer: an effective and simple sternal elevation manoeuvre

The Nuss procedure requires the creation of a substernal tunnel for bar positioning. This is a manoeuvre that can be dangerous, and cardiac perforation has occurred in a few cases. Our purpose was to describe two technical modifications that enable the prevention of these fatal complications. A series of 25 patients with pectus excavatum were treated with a modification of the Nuss procedure that included the entrance in the left haemithorax first, and the use of the retractor to lift the sternum, with the consequent lowering displacement of the heart. These modified techniques have certain advantages: (i) the narrow anterior mediastinum between the sternum and the pericardial sac is expanded by pulling up the sternum; (ii) the thoracoscopic visualization of the tip of the introducer during tunnel creation is improved; (iii) the rubbing of the introducer against the pericardium is minimized; (iv) the exit path of the introducer can be guided by the surgeon's finger and (v) haemostasis and integrity of the pericardial sac can be more easily confirmed. We observed that with these manoeuvres, the risk of pericardial sac and cardiac injury can be markedly reduced.

Rapid sample preparation procedure for As speciation in food samples by LC-ICP-MS

This paper describes a rapid method for arsenic (As) speciation by LC-ICP-MS in several types of food samples. Prior to analysis, samples were milled and the As species extracted from biological tissues by sonication in only 2 min with a solution containing MeOH (10%, v/v) plus HNO3 (2%, v/v). As species were separated by LC using an anion exchange column. Method detection limits for AsB, As3+,DMA, MMA and As5+ were 1.3, 0.9, 0.6, 0.7 and 0.8 ng g(-1), respectively. Method accuracy and precision were traceable to Certified Reference Materials SRM1577 bovine liver from the National Institute of Standards and Technology, CE278 mussel tissue from the Institute of Reference Materials and Measurements and DOLT-3 dogfish liver tissue and DORM-3 fish protein from the National Research Council of Canada. Finally, the method was applied to speciate As in food samples (egg, fish muscle, beef and chicken) purchased in Brazilian markets.

Simultaneous Quantification of Lycopene, beta-Carotene, Retinol and alpha-Tocopherol in Plasma after a Simple Extraction Procedure: Stability Study and Application to Human Volunteers

A method for the simultaneous quantification of lycopene, beta-carotene, retinol and alpha-tocopherol by high-performance liquid chromatography (HPLC) with Vis/fluorescence detection with isocratic elution was optimized and validated. The method consists of a rapid and simple liquid-liquid extraction procedure and a posterior quantification of extracted supernatants by HPLC. Aliquots of plasma were stored at -20 degrees C for three months for stability study. The methodology was applied to samples from painters and individuals not exposed to paints (n = 75). The assay was linear for all vitamins (r > 0.99). Intra-and inter-run precisions were obtained with coefficient of variation smaller than 5%. The accuracies ranged from 0.29 to -5.80% and recoveries between 92.73 and 101.97%. Plasma samples and extracted supernatants were stable for 60 days at -20 degrees C. A significant decrease of lycopene, beta-carotene and retinol concentrations in plasma from exposed individuals compared to non-exposed individuals (p < 0.05) was observed. The method is simple, reproducible, precise, accurate and sensitive, and can be routinely utilized in clinical laboratories.

Nanogravimetric study of lead underpotential deposition on selenium thin films as a semiconductor alloy formation procedure

An electrochemical quartz crystal microbalance Au electrode modified with a Se thin film was used to investigate the electrochemical behavior of lead ad-atoms using underpotential deposition (UPD) conditions. A specific quasi-reversible process was observed during the reduction of Pb2+ on Se thin films in perchloric acid media. The charge density of Pb ad-atoms on Se thin film (46.86 mu C cm(-2)) suggests a recovery of 0.1 monolayers, which is in good agreement with EQCM data. The Se thin film can be successfully alloyed with Pb atoms that are deposited by chronoamperometry using time intervals large enough to allow for diffusion toward the inner Se phase. Linear sweep voltammetry combined with EQCM in perchloric acid was used to characterize the amount of Pb absorbed in the Se thin film. These findings offer a new strategy for alloy formation in semiconductor films using UPD as an effective tool to quantify the exact amount of the incorporated metal.

An environmentally friendly analytical procedure for nickel determination by atomic and molecular spectrometry after cloud point extraction in different samples

Cloud point extraction (CPE) was employed for separation and preconcentration prior to the determination of nickel by graphite furnace atomic absorption spectrometry (GFAAS), flame atomic absorption spectrometry (FAAS) or UV-Vis spectrophotometry. Di-2-pyridyl ketone salicyloylhydrazone (DPKSH) was used for the first time as a complexing agent in CPE. The nickel complex was extracted from the aqueous phase using the Triton X-114 surfactant. Under optimized conditions, limits of detection obtained with GFAAS, FAAS and UV-Vis spectrophotometry were 0.14, 0.76 and 1.5 mu g L-1, respectively. The extraction was quantitative and the enrichment factor was estimated to be 27. The method was applied to natural waters, hemodialysis concentrates, urine and honey samples. Accuracy was evaluated by analysis of the NIST 1643e Water standard reference material.

An analysis of Taguchi's on-line quality monitoring procedure for variables based on the results of a sequence of inspections

In this paper, a procedure for the on-line process control of variables is proposed. This procedure consists of inspecting the m-th item from every m produced items and deciding, at each inspection, whether the process is out-of-control. Two sets of limits, warning (µ0 ± W) and control (µ0 ± C), are used. If the value of the monitored statistic falls beyond the control limits or if a sequence of h observations falls between the warning limits and the control limits, the production is stopped for adjustment; otherwise, production goes on. The properties of an ergodic Markov chain are used to obtain an expression for the average cost per item. The parameters (the sampling interval m, the widths of the warning, the control limits W and C(W < C), and the sequence length (h) are optimized by minimizing the cost function. A numerical example illustrates the proposed procedure.