Ajuste oclusal na Ortodontia: Por que, quando e como?

Introduction: The knowledge of dental occlusion should be considered the basic foundation to an excellent orthodontic practice. The patient's diagnose without the centric relation assessment can take the orthodontist to an unpleasant surprises. The use of rectangular archwires requires occlusal contacts been checked to decide what kind of the dental movement will be necessary to achieve the dental equilibrium and mainly to investigate if the movement will be possible. Considering the occlusal surfaces complexity, the occlusal adjustment by selective grinding should be performed during the orthodontic treatment to allow vertical dental movements reducing treatment's time. Occlusal interferences are responsible not only for biomechanics adverse effects, producing undesirable dental movements, but also for potential side effects such as excessive forces (occlusal trauma), leading to roots reabsorption. The occlusal adjustment is a determinant point on dental balance after the end of orthodontics treatments, where each posterior occlusal tooth contacts A and B, or B and C on buccolingual aspect, as well as the stoppers and equalizers contacts on mesiodistal direction must be achieved and well established. The appropriate role of anterior teeth in mandibular movements must be determined, allowing immediate disclusion of posterior teeth, known as anterior guide, and promoting protecting muscle forces to the stomatognathic system. Selective grinding should not be used. in place of well planned and executed orthodontic movement. Aim: The aim of this article is to present the rationale use of occlusal adjustment in Orthodontics.

Metal separation from mixed types of batteries using selective precipitation and liquid-liquid extraction techniques

The purpose of this paper is to study metal separation from a sample composed of a mixture of the main types of spent household batteries, using a hydrometallurgical route, comparing selective precipitation and liquid-liquid extraction separation techniques. The preparation of the solution consisted of: grinding the waste of mixed batteries, reduction and volatile metals elimination using electric furnace and acid leaching. From this solution two different routes were studied: selective precipitation with sodium hydroxide and liquid-liquid extraction using Cyanex 272 [bis(2,4,4-trimethylpentyl) phosphoric acid] as extracting agent. The best results were obtained from liquid-liquid extraction in which Zn had a 99% extraction rate at pH 2.5. More than 95% Fe was extracted at pH 7.0, the same pH at which more than 90% Ce was extracted. About 88% Mn, Cr and Co was extracted at this pH. At pH 3.0, more than 85% Ni was extracted, and at pH 3.5 more than 80% of Cd and La was extracted. (C) 2010 Elsevier Ltd. All rights reserved.

Design, Synthesis And Biological Evaluation Of Hybrid Bioisoster Derivatives Of N-acylhydrazone And Furoxan Groups With Potential And Selective Anti-trypanosoma Cruzi Activity.

Hybrid bioisoster derivatives from N-acylhydrazones and furoxan groups were designed with the objective of obtaining at least a dual mechanism of action: cruzain inhibition and nitric oxide (NO) releasing activity. Fifteen designed compounds were synthesized varying the substitution in N-acylhydrazone and in furoxan group as well. They had its anti-Trypanosoma cruzi activity in amastigotes forms, NO releasing potential and inhibitory cruzain activity evaluated. The two most active compounds (6, 14) both in the parasite amastigotes and in the enzyme contain the nitro group in para position of the aromatic ring. The permeability screening in Caco-2 cell and cytotoxicity assay in human cells were performed for those most active compounds and both showed to be less cytotoxic than the reference drug, benznidazole. Compound 6 was the most promising, since besides activity it showed good permeability and selectivity index, higher than the reference drug. Thereby the compound 6 was considered as a possible candidate for additional studies.

Improved Selective Cholesterol Adsorption By Molecularly Imprinted Poly(methacrylic Acid)/silica (pmaa-sio₂) Hybrid Material Synthesized With Different Molar Ratios.

The present paper describes the synthesis of molecularly imprinted polymer - poly(methacrylic acid)/silica and reports its performance feasibility with desired adsorption capacity and selectivity for cholesterol extraction. Two imprinted hybrid materials were synthesized at different methacrylic acid (MAA)/tetraethoxysilane (TEOS) molar ratios (6:1 and 1:5) and characterized by FT-IR, TGA, SEM and textural data. Cholesterol adsorption on hybrid materials took place preferably in apolar solvent medium, especially in chloroform. From the kinetic data, the equilibrium time was reached quickly, being 12 and 20 min for the polymers synthesized at MAA/TEOS molar ratio of 6:1 and 1:5, respectively. The pseudo-second-order model provided the best fit for cholesterol adsorption on polymers, confirming the chemical nature of the adsorption process, while the dual-site Langmuir-Freundlich equation presented the best fit to the experimental data, suggesting the existence of two kinds of adsorption sites on both polymers. The maximum adsorption capacities obtained for the polymers synthesized at MAA/TEOS molar ratios of 6:1 and 1:5 were found to be 214.8 and 166.4 mg g(-1), respectively. The results from isotherm data also indicated higher adsorption capacity for both imprinted polymers regarding to corresponding non-imprinted polymers. Nevertheless, taking into account the retention parameters and selectivity of cholesterol in the presence of structurally analogue compounds (5-α-cholestane and 7-dehydrocholesterol), it was observed that the polymer synthesized at the MAA/TEOS molar ratio of 6:1 was much more selective for cholesterol than the one prepared at the ratio of 1:5, thus suggesting that selective binding sites ascribed to the carboxyl group from MAA play a central role in the imprinting effect created on MIP.

Short-Term effect of COX-2 selective inhibitor as an adjunct for the treatment of periodontal disease: a clinical double-blind study in humans

Adjunctive therapeutic strategies that modulate the inflammatory mediators can play a significant role in periodontal therapy. In this double-blind, placebo-controlled study, 60 subjects diagnosed as periodontitis patients were evaluated for 28 days after periodontal treatment combined with selective cyclooxygenase-2 (COX-2) inhibitor. The experimental group received scaling and root planning (SRP) combined with the Loxoprofen antiinflammatory drug (SRP+Loxoprofen). The control group received SRP combined with placebo (SRP+placebo). Plaque index (PI), probing pocket depth (PD) and bleeding on probing (BOP) were monitored with an electronic probe at baseline and after 14 and 28 days. Both groups displayed clinical improvement in PD, PI and BOP. They also showed statistically similar values (p>0.05) of PD reduction on day 14 (0.4 mm) and on day 28 (0.6 mm). At the baseline, few deeper sites (>7 mm) from SRP+Loxoprofen group were responsible and most PD reduction was observed after 14 days (p<0.05). The percentage of remaining deep pockets (>7 mm) after 14 days in the SRP+Loxoprofen group was significantly lower (p<0.05) than in the SRP+placebo group. Loxoprofen presents potential effect as an adjunct of periodontal disease treatment, but long-term clinical trials are necessary to confirm its efficacy.

Performance of transport and selective media for swine Bordetella bronchiseptica recovery and it comparison to polymerase chain reaction detection

Three comparative assays were performed seeking to improve the sensitivity of the diagnosis of Bordetella bronchiseptica infection analyzing swine nasal swabs. An initial assay compared the recovery of B. bronchiseptica from swabs simultaneously inoculated with B. bronchiseptica and some interfering bacteria, immersed into three transport formulations (Amies with charcoal, trypticase soy broth and phosphate buffer according to Soerensen supplemented with 5% of bovine fetal serum) and submitted to different temperatures (10ºC and 27ºC) and periods of incubation (24, 72 and 120 hours). A subsequent assay compared three selective media (MacConkey agar, modified selective medium G20G and a ceftiofur medium) for their recovery capabilities from clinical specimens. One last assay compared the polymerase chain reaction to the three selective media. In the first assay, the recovery of B. bronchiseptica from transport systems was better at 27ºC and the three formulations had good performances at this temperature, but the collection of qualitative and quantitative analysis indicated the advantage of Amies medium for nasal swabs transportation. The second assay indicated that MacConkey agar and modified G20G had similar results and were superior to the ceftiofur medium. In the final assay, polymerase chain reaction presented superior capability of B. bronchiseptica detection to culture procedures.

Ticks produce highly selective chemokine binding proteins with antiinflammatory activity

Bloodsucking parasites such as ticks have evolved a wide variety of immunomodulatory proteins that are secreted in their saliva, allowing them to feed for long periods of time without being detected by the host immune system. One possible strategy used by ticks to evade the host immune response is to produce proteins that selectively bind and neutralize the chemokines that normally recruit cells of the innate immune system that protect the host from parasites. We have identified distinct cDNAs encoding novel chemokine binding proteins (CHPBs), which we have termed Evasins, using an expression cloning approach. These CHBPs have unusually stringent chemokine selectivity, differentiating them from broader spectrum viral CHBPs. Evasin-1 binds to CCL3, CCL4, and CCL18; Evasin-3 binds to CXCL8 and CXCL1; and Evasin-4 binds to CCL5 and CCL11. We report the characterization of Evasin-1 and -3, which are unrelated in primary sequence and tertiary structure, and reveal novel folds. Administration of recombinant Evasin-1 and - 3 in animal models of disease demonstrates that they have potent antiinflammatory properties. These novel CHBPs designed by nature are even smaller than the recently described single-domain antibodies (Hollinger, P., and P. J. Hudson. 2005. Nat. Biotechnol. 23: 1126-1136), and may be therapeutically useful as novel antiinflammatory agents in the future.

Evaluation technique for determining wheel performance in the grinding of aerospace materials

Nickel-based super alloys are used in a variety of applications in which high-temperature strength and resistance to creep, corrosion, and oxidation are required, such as in aircraft gas turbines, combustion chambers, and automotive engine valves. The properties that make these materials suitable for these applications also make them difficult to grind. Grinding systems for such materials are often built around vitrified cBN (cubic boron nitride) wheels to realize maximum productivity and minimum cost per part. Conditions that yield the most economical combination of stock removal rate and wheel wear are key to the successful implementation of the grinding system. Identifying the transition point for excessive wheel wear is important. The aim of this study is to compare the performance of different cBN wheels when grinding difficult-to-grind (DTG) materials by determining the 'wheel wear characteristic curve', which correlates the G-ratio to the calculated tangential force per abrasive grain. With the proposed methodology, a threshold force per grit above which the wheel wear rate increases rapidly can be quickly identified. A comparison of performance for two abrasive product formulations in the grinding of three materials is presented. The obtained results can be applied for the development of grinding applications for DTG materials.

Selective activation of the rectus abdominis muscle during low-intensity and fatiguing tasks

In order to understand the potential selective activation of the rectus abdominis muscle, we conducted two experiments. In the first, subjects performed two controlled isometric exercises: the curl up (supine trunk raise) and the leg raise (supine bent leg raise) at low intensity (in which only a few motor units are recruited). In the second experiment, subjects performed the same exercises, but they were required to maintain a certain force level in order to induce fatigue. We recorded the electromyographic (EMG) activities of the lower and upper portions of the rectus abdominis muscle during the exercises and used spatial-temporal and frequency analyses to describe muscle activation patterns. At low-intensity contractions, the ratio between the EMG intensities of the upper and lower portions during the curl up exercise was significantly larger than during the leg raise exercise (p = 0.02). A cross-correlation analysis indicated that the signals of the abdominal portions were related to each other and this relation did not differ between the tasks (p = 0.12). In the fatiguing condition, fatigue for the upper portion was higher than for the lower portion during the curl up exercise (p = 0.008). We conclude that different exercises evoked, to a certain degree, individualized activation of each part of the rectus abdominis muscle, but different portions of the rectus abdominis muscle contributed to the same task, acting like a functional unit. These results corroborate the relevance of varying exercise to modify activation patterns of the rectus abdominis muscle.

Selective Decrease of Components of the Creatine Kinase System and ATP Synthase Complex in Chronic Chagas Disease Cardiomyopathy

Background: Chronic Chagas disease cardiomyopathy (CCC) is an inflammatory dilated cardiomyopathy with a worse prognosis than other cardiomyopathies. CCC occurs in 30 % of individuals infected with Trypanosoma cruzi, endemic in Latin America. Heart failure is associated with impaired energy metabolism, which may be correlated to contractile dysfunction. We thus analyzed the myocardial gene and protein expression, as well as activity, of key mitochondrial enzymes related to ATP production, in myocardial samples of end-stage CCC, idiopathic dilated (IDC) and ischemic (IC) cardiomyopathies. Methodology/Principal Findings: Myocardium homogenates from CCC (N = 5), IC (N = 5) and IDC (N = 5) patients, as well as from heart donors (N = 5) were analyzed for protein and mRNA expression of mitochondrial creatine kinase (CKMit) and muscular creatine kinase (CKM) and ATP synthase subunits aplha and beta by immunoblotting and by real-time RT-PCR. Total myocardial CK activity was also assessed. Protein levels of CKM and CK activity were reduced in all three cardiomyopathy groups. However, total CK activity, as well as ATP synthase alpha chain protein levels, were significantly lower in CCC samples than IC and IDC samples. CCC myocardium displayed selective reduction of protein levels and activity of enzymes crucial for maintaining cytoplasmic ATP levels. Conclusions/Significance: The selective impairment of the CK system may be associated to the loss of inotropic reserve observed in CCC. Reduction of ATP synthase alpha levels is consistent with a decrease in myocardial ATP generation through oxidative phosphorylation. Together, these results suggest that the energetic deficit is more intense in the myocardium of CCC patients than in the other tested dilated cardiomyopathies.

Flow injection analysis of paracetamol using a biomimetic sensor as a sensitive and selective amperometric detector

This work describes the coupling of a biomimetic sensor to a flow injection system for the sensitive determination of paracetamol. The sensor was prepared as previously described in the literature (M. D. P. T. Sotomayor, A. Sigoli, M. R. V. Lanza, A. A. Tanaka and L. T. Kubota, J. Braz. Chem. Soc., 2008, 19, 734) by modifying a glassy carbon electrode surface with a Nafion (R) membrane doped with iron tetrapyridinoporphyrazine (FeTPyPz), a biomimetic catalyst of the P450 enzyme. The performance of the sensor for paracetamol detection was investigated and optimized in a flow injection system (FIA) using a wall jet electrochemical cell. Under optimized conditions a wide linear response range (1.0 x 10(-5) to 5.0 x 10(-2) mol L(-1)) was obtained, with a sensitivity of 2579 (+/- 129) mu A L mu mol(-1). The detection and quantification limits of the sensor for paracetamol in the FIA system were 1.0 and 3.5 mu mol L(-1), respectively. The analytical frequency was 51 samples h(-1), and over a period of five days (320 determinations) the biosensor maintained practically the same response. The system was successfully applied to paracetamol quantification in seven pharmaceutical formulations and in water samples from six rivers in Sao Paulo State, Brazil.

Evaluation of grinding methods for pellets preparation aiming at the analysis of plant materials by laser induced breakdown spectrometry

It has been demonstrated that laser induced breakdown spectrometry (LIBS) can be used as an alternative method for the determination of macro (P, K. Ca, Mg) and micronutrients (B, Fe, Cu, Mn, Zn) in pellets of plant materials. However, information is required regarding the sample preparation for plant analysis by LIBS. In this work, methods involving cryogenic grinding and planetary ball milling were evaluated for leaves comminution before pellets preparation. The particle sizes were associated to chemical sample properties such as fiber and cellulose contents, as well as to pellets porosity and density. The pellets were ablated at 30 different sites by applying 25 laser pulses per site (Nd:YAG@1064 nm, 5 ns, 10 Hz, 25J cm(-2)). The plasma emission collected by lenses was directed through an optical fiber towards a high resolution echelle spectrometer equipped with an ICCD. Delay time and integration time gate were fixed at 2.0 and 4.5 mu s, respectively. Experiments carried out with pellets of sugarcane, orange tree and soy leaves showed a significant effect of the plant species for choosing the most appropriate grinding conditions. By using ball milling with agate materials, 20 min grinding for orange tree and soy, and 60 min for sugarcane leaves led to particle size distributions generally lower than 75 mu m. Cryogenic grinding yielded similar particle size distributions after 10 min for orange tree, 20 min for soy and 30 min for sugarcane leaves. There was up to 50% emission signal enhancement on LIBS measurements for most elements by improving particle size distribution and consequently the pellet porosity. (C) 2011 Elsevier B.V. All rights reserved.

A TR beta-selective agonist confers resistance to diet-induced obesity

Thyroid hormone receptor beta (TR beta also listed as THRB oil the MGI Database)-selective agonists activate brown adipose tissue (BAT) thermogenesis, while only minimally affecting cardiac activity or lean body mass. Here, we tested the hypothesis that daily administration of the TR beta agonist GC-24 prevents the metabolic alterations associated with a hypercaloric diet. Rats were placed on a high-fat diet and after a month exhibited increased body weight (BW) and adiposity, fasting hyperglycemia and glucose intolerance, increased plasma levels of triglycerides, cholesterol, nonesterified Fatty acids and interleukin-6. While GC-24 administration to these animals did not affect food ingestion or modified the progression of BW gain, it did increase energy, g the increase in adiposity Without expenditure, eliminating causing cardiac hypertrophy Fasting hyperglycemia remained unchanged, but treatment with GC-24 improved glucose I tolerance by increasing insulin Sensitivity and also normalized plasma triglyceride levels. plasma cholesterol levels were only Partially normalized and liver cholesterol content remained high in the GC-24-treated animals. Gene expression in liver, skeletal muscle, and white adipose tissue was only minimally affected by treatment with GC-24, with the main target being BAT In conclusion, during high-fat feeding treatment with the TR beta-selective agonist, GC-24 only partially improves metabolic control probably as a result Of accelerating the resting metabolic rate. Journal of Endocrinology (2009) 203, 291-299

Thermal error evaluation and modelling of a CNC cylindrical grinding machine

With the relentless quest for improved performance driving ever tighter tolerances for manufacturing, machine tools are sometimes unable to meet the desired requirements. One option to improve the tolerances of machine tools is to compensate for their errors. Among all possible sources of machine tool error, thermally induced errors are, in general for newer machines, the most important. The present work demonstrates the evaluation and modelling of the behaviour of the thermal errors of a CNC cylindrical grinding machine during its warm-up period.

Industrial challenges in grinding

This keynote paper aims at analyzing relevant industrial demands for grinding research. The chosen focus is to understand what are the main research challenges in the extensive industrial use of the process. Since the automotive applications are the most important driving forces for grinding development, the paper starts with an analysis on the main trends in more efficient engines and the changes in their components that will affect the grinding performance. A view from 23 machine tool builders is also presented based on a survey made in interviews and during the EMO and IMTS machine tool shows. Case studies received by the STC G members were used to show how research centers and industries are collaborating. A view from the authors and the final conclusions show hot topics for future grinding research. (C) 2009 CIRP.