Photorefractive phase coupling measurement using self-stabilized recording technique

The measurement of the phase shift φ between the transmited and difracted beams interfering along the same direction behind the hologram recorded in a photorefractive crystal is directly and accurately measured using a self-stabilized recording technique. The measured phase shift as a function of the applied electric field allows computing the Debye screening lenght and the effectively applied field coefficient of an undoped Bi 12TiO 20 crystal. The result is in good agreement with the already available information about this sample. © 2008 American Institute of Physics.

La technique de l’arc segmenté. Contrôle de l’ancrage et modification significative du profil facial : une étude de cas

This article evaluates space closure mechanics efficiency in an extraction case where maximum anchorage was a requirement. The Segmented Arch Technique (SAT) was utilized as an anchorage control strategy to obtain maximum anterior retraction and, in consequence, significant facial profile change. A 20-year-10-month old woman needed severe labial and profile changes. The patient had four premolars extracted and SAT with type A mechanics [1] (Marcotte [2] activation protocol) was applied. The results showed significant reduction in labial protrusion and incisal angulation with effective anchorage control. The results were compared to others available in the literature derived from different techniques, where anterior retraction was also accomplished with maximum anchorage [3-7]. In conclusion, the SAT with type A mechanics has been shown to be another treatment option when significant changes in the soft-tissue profile are needed in extraction cases. © 2008. CEO. Published by Elsevier Masson SAS. All rights reserved.

Bone spreading technique a case report

Bone spreading technique (BST) is a horizontal augmentation with minimal trauma for simultaneous implant placement and an alternative to Summer's osteotome technique both for its clinical use and for the armamentarium. The foremost advantage of the crest dilation technique is a substantially less invasive method; the buccal wall expands after the medullary bone is compressed against the cortical bone. The lateral dilation and compaction of medullary bone improved primary stability. The vital difference is that the BST used in this case report avoided discomfort of the patient, thus eliminating the need for malleting.

Longitudinal bond strength evaluation using the deproteinized dentin technique

This study evaluated bond strength to dentin as a result of storage time for conventional adhesive systems (with or without collagen) that had been deproteinized with 10% sodium hypochlorite (NaOCl). For this study, 72 human molars were sectioned in a mesiodistal axial plane and embedded in acrylic resin; at that point, the vestibular and lingual surfaces were worn down with abrasive paper. Acid etching was performed for 15 seconds (using 37% phosphoric acid) and the specimens were divided into 12 groups (n = 6), depending on the adhesive system used, the dentin treatment performed, and the length of evaluation (24 hours or six months). A resin composite was inserted over the prepared area with the aid of a metal matrix. Following a mechanical shear test, fractured surfaces were analyzed by stereomicroscope and the data were submitted to ANOVA and Tukey's test. It was concluded that the dentin deproteinization treatment with 10% NaOCI improved the bond strength in five of the six groups. The bond strength after 24 hours was significantly higher than the bond strength measured after six months. Of the three adhesive systems tested in this study, DenTASTIC UNO demonstrated the lowest bond strength.

Microhardness of glass ionomer cements indicated for the ART technique according to surface protection treatment and storage time

The aim of this study was to assess the microhardness of 5 glass ionomer cements (GIC) - Vidrion R (V, SS White), Fuji IX (F, GC Corp.), Magic Glass ART (MG, Vigodent), Maxxion R (MR, FGM) and ChemFlex (CF, Dentsply) - in the presence or absence of a surface protection treatment, and after different storage periods. For each GIC, 36 test specimens were made, divided into 3 groups according to the surface protection treatment applied - no protection, varnish or nail varnish. The specimens were stored in distilled water for 24 h, 7 and 30 days and the microhardness tests were performed at these times. The data obtained were submitted to the ANOVA for repeated measures and Tukey tests (α = 5%). The results revealed that the mean microhardness values of the GICs were, in decreasing order, as follows: F > CF = MR > MG > V; that surface protection was significant for MR, at 24 h, without protection (64.2 ± 3.6a), protected with GIC varnish (59.6 ± 3.4b) and protected with nail varnish (62.7 ± 2.8ab); for F, at 7 days, without protection (97.8 ± 3.7ab), protected with varnish (95.9 ± 3.2b) and protected with nail varnish (100.8 ± 3.4a); and at 30 days, for F, without protection (98.8 ± 2.6b), protected with varnish (103.3 ± 4.4a) and protected with nail varnish (101 ± 4.1ab) and, for V, without protection (46 ± 1.3b), protected with varnish (49.6 ± 1.7ab) and protected with nail varnish (51.1 ± 2.6a). The increase in storage time produced an increase in microhardness. It was concluded that the different GICs, surface protection treatments and storage times could alter the microhardness values.

Radiographic study of ossification of the pterygospinous and pterygoalar ligaments by the Hirtz axial technique.

The correct radiographic identification of ossification of the pterygospinous and pterygoalar ligaments plays an important role in surgical procedures for the treatment of trigeminal neuralgia. Most of these procedures are performed through the foramen ovale, a site where these ligaments can be found to be partially or completely ossified. We studied the radiographic features of these ossified ligaments and their location in relation to the foramen ovale by the Hirtz axial technique. For this purpose, 93 dry skulls from the Discipline of Anatomy, São José dos Campos Dental School, UNESP, which presented partial or complete ossification of these ligaments, were radiographed. The pterygospinous ligament was detected on 27.97% of radiographs and was partially ossified in 19.36% of cases and completely ossified in 8.61%. The pterygoalar ligament was present in 62.35% of radiographs, being partially ossified in 49.44% and completely ossified in 12.91%. The pterygospinous ligaments was found to be partially and completely ossified on the same radiograph in 3.23% of cases, whereas the pterygoalar ligament appeared partially and completely ossified on the same radiograph in 6.45%. Furthermore, the pterygospinous ligament was thinner than the pterygoalar ligament and located more medially in relation to the foramen ovale. The pterygoalar ligament formed a large bone bar lateral to the foramen ovale, often obliterating the lumen of the latter. The Hirtz axial technique is an excellent tool for the observation of complete or partial ossification of the pterygospinous and pterygoalar ligaments in surgical procedures for the treatment of trigeminal neuralgia performed through the foramen ovale.

Evaluation of a two-step pouring technique for implant-supported prostheses impression

The aim of this study was to evaluate the efficacy of a pouring technique for implant-supported prostheses impressions. A metallic matrix (control group) with two implants positioned at 90 and 65 degrees was fabricated. The matrix was submitted to the direct transfer impression technique. In group CP (conventional pouring - n = 10), casts were obtained by the conventional pouring technique. In group EP (experimental pouring - n = 10), the analogs were embraced with latex tubes before the first pouring and then submitted to a second pouring. Vertical misfit and implants/analogs inclinations were evaluated. Data were analyzed by analysis of variance and Tukey's test (p < .05). Results demonstrated significant difference (p < .05) between control and experimental groups for misfit measurement in perpendicular implant/analog and between control group and group EP in leaning implant/analog. Considering inclination, there were significant differences (p < .05) between control and experimental groups for leaning analogs. Independently of the pouring technique, perpendicular implants produced more accurate casts.

Mathematical decomposition technique applied to the probabilistic power flow problem

In this paper a framework based on the decomposition of the first-order optimality conditions is described and applied to solve the Probabilistic Power Flow (PPF) problem in a coordinated but decentralized way in the context of multi-area power systems. The purpose of the decomposition framework is to solve the problem through a process of solving smaller subproblems, associated with each area of the power system, iteratively. This strategy allows the probabilistic analysis of the variables of interest, in a particular area, without explicit knowledge of network data of the other interconnected areas, being only necessary to exchange border information related to the tie-lines between areas. An efficient method for probabilistic analysis, considering uncertainty in n system loads, is applied. The proposal is to use a particular case of the point estimate method, known as Two-Point Estimate Method (TPM), rather than the traditional approach based on Monte Carlo simulation. The main feature of the TPM is that it only requires resolve 2n power flows for to obtain the behavior of any random variable. An iterative coordination algorithm between areas is also presented. This algorithm solves the Multi-Area PPF problem in a decentralized way, ensures the independent operation of each area and integrates the decomposition framework and the TPM appropriately. The IEEE RTS-96 system is used in order to show the operation and effectiveness of the proposed approach and the Monte Carlo simulations are used to validation of the results. © 2011 IEEE.

A CAD/CAM flapless surgical technique and immediate prosthesis: A clinical report

Background: This article describes a clinical report with a new system for guided surgical treatment and immediate load prosthesis in the flapless surgical technique. Case report: Based on a computed tomography (CT) of a 64 - year-old edentulous patient, the cross sections were reformatted and used to construct a virtual planning of the implants and a guide template in Dental Slice. Six dental implants were placed in the maxilla and mandible using a Slice Guide System. Following a 30-month in maxilla and 24-month in mandible healing period, the clinical and radiographic evaluation and computed tomography (CT) showed good clinical stability. The Slice Guide System proved satisfactory for the Flapless Surgical Technique in dental implants.

A PZT-based technique for SHM using the coherence function

This paper presents a new approach for damage detection in structural health monitoring systems exploiting the coherence function between the signals from PZT (Lead Zirconate Titanate) transducers bonded to a host structure. The physical configuration of this new approach is similar to the configuration used in Lamb wave based methods, but the analysis and operation are different. A PZT excited by a signal with a wide frequency range acts as an actuator and others PZTs are used as sensors to receive the signal. The coherences between the signals from the PZT sensors are obtained and the standard deviation for each coherence function is computed. It is demonstrated through experimental results that the standard deviation of the coherence between the signals from the PZTs in healthy and damaged conditions is a very sensitive metric index to detect damage. Tests were carried out on an aluminum plate and the results show that the proposed methodology could be an excellent approach for structural health monitoring (SHM) applications.

Evaluation of water amount in hydrated ethanol fuel by gamma-ray attenuation technique

In this work, is presented an alternative and non conventional technique for evaluate the water amount present in the hydrated ethanol used as automotive fuel. The standard technique used in this kind of measure is the use of densimeter. The proposal of this work is based on the measure of the linear attenuation coefficient of hydrated ethanol, using the gamma-ray attenuation technique. The water amount, in volume, can be determined knowing the linear attenuation coefficient of hydrated ethanol. Samples of hydrated ethanol, collected at fuel stations, located in Sorocaba, SP, Brazil, were analyzed and the results showed the feasibility of the technique. © 2011 American Institute of Physics.

Ligature of external carotid artery as an optional technique in a patient with von Willebrand disease

The von Willebrand disease (vWD) is a hereditary coagulopathy. There is no gender predilection. Clinically characterized by mucocutaneous bleeding, especially nose bleeding, menorrhagia and bleeding after trauma. This article reports a case of a 52-year-old Caucasian male patient with vWD, who presented with extensive bleeding in the tongue after a lacerating injury caused by accidental biting, and describes some clinical, pathological and treatment aspects of vWD. After repeated attempts to suture the wound and replace clotting factors, a decision was made to perform the ligature of the external carotid artery ipsilateral to the injury. There was favorable resolution of the case, with a good aspect of the scar 2 months after ligation. This case reinforces that it is extremely important to make a thorough review of medical history of all patients, searching for possible bleeding disorders or previous family history.

Implant removal by means of an expansion of the alveolar bony crest: Report of a clinical technique

Aim: To describe the adaptation of the Edentulous Ridge Expansion (E.R.E.) technique for implant removal. Material and Methods: The E.R.E. technique for the removal of failed implants is described in detail. A clinical case is also reported. In a patient carrying a full arch removable prosthesis in the upper jaw, sustained by two bars, two out of five implants were found to be fractured. Bucco-lingual partial-thickness flaps were used to access the fractured implants. The implants were subsequently removed applying the E.R.E. technique. Two recipient sites were prepared in the same position, using bone expanders, and two new implants were installed. Results: After 4 months of healing, the implants were integrated and a new bar was fabricated, and the old prosthesis readapted. Conclusion: The ERE technique may be successfully applied for the removal of failed implants, and the immediate or delayed reinstallation of new implants. © 2012 John Wiley & Sons A/S.

QK-Means: A clustering technique based on community detection and K-Means for deployment of cluster head nodes

Wireless Sensor Networks (WSN) are a special kind of ad-hoc networks that is usually deployed in a monitoring field in order to detect some physical phenomenon. Due to the low dependability of individual nodes, small radio coverage and large areas to be monitored, the organization of nodes in small clusters is generally used. Moreover, a large number of WSN nodes is usually deployed in the monitoring area to increase WSN dependability. Therefore, the best cluster head positioning is a desirable characteristic in a WSN. In this paper, we propose a hybrid clustering algorithm based on community detection in complex networks and traditional K-means clustering technique: the QK-Means algorithm. Simulation results show that QK-Means detect communities and sub-communities thus lost message rate is decreased and WSN coverage is increased. © 2012 IEEE.