Artificial neural networks for load flow and external equivalents studies

In this paper an artificial neural network (ANN) based methodology is proposed for (a) solving the basic load flow, (b) solving the load flow considering the reactive power limits of generation (PV) buses, (c) determining a good quality load flow starting point for ill-conditioned systems, and (d) computing static external equivalent circuits. An analysis of the input data required as well as the ANN architecture is presented. A multilayer perceptron trained with the Levenberg-Marquardt second order method is used. The proposed methodology was tested with the IEEE 30- and 57-bus, and an ill-conditioned 11-bus system. Normal operating conditions (base case) and several contingency situations including different load and generation scenarios have been considered. Simulation results show the excellent performance of the ANN for solving problems (a)-(d). (C) 2010 Elsevier B.V. All rights reserved.

Treatment of segmental tibial defects using acute bone shortening followed by gradual lengthening with circular external fixator

The aim of this study was to clinically and radiographically evaluate acute bone shortening followed by gradual lengthening in the treatment of large segmental tibia defects induced in seven clinically normal dogs. A circular external fixator was assembled with one proximal 5/8-circle ring, one middle ring and one distal ring connected with three rods. Thirty per cent of the tibia and fibula were removed in the middle and distal parts of the diaphyses, between the middle and distal rings. Acute bone shortening with compression of proximal and distal segments was performed. A subperiosteal osteotomy was performed between the half-ring and middle ring. Bone distraction started 7 days after surgery; after lengthening, the apparatus was left in place for 14 weeks for consolidation of regenerated bone. The frame was removed at the end of this period, and the dogs observed for four more weeks. Functional results were considered excellent in two, good in three and fair in the other two dogs. Bone regeneration within the distraction gap was obtained 14 weeks after neutral fixation period. We concluded that acute bone shortening followed by gradual lengthening by Ilizarov method can be used to treat extensive tibial defects in dogs, although it presents limb temporary abnormal limb shape and unequal length as early disadvantages.

Paracoccidioidomycosis of external genitalia: report of six new cases and review of the literature

BACKGROUND: Paracoccidioidomycosis is a systemic mycosis of dermatological interest due to the frequency of cutaneous and mucosal lesions. The involvement of the external genitalia is extremely rare and few cases have been reported.OBJECTIVE: To study the prevalence of external genitalia lesions in paracoccidioidomycosis patients, identify clinical characteristics and compare with what is observed in the specific literature.METHODS: This is a cross-sectional, descriptive study, with focus on paracoccidioiodomycosis patients with external genitalia lesions. The demographic and clinical aspects of cases were compared with what has been reported so far on LILACS, SciELO e MEDLINE data bases.RESULTS: Data of 483 cases of paracoccidioidomycosis were studied in a 42-year period. Six (1.2%) patients showed specific lesions on external genitalia. Five patients were male with mean age of 47.2 years and all of them presented with the chronic multifocal clinical form. Only one, a 15-year-old female patient was observed who showed a subacute clinical form, juvenile type.CONCLUSIONS: Compromise of the genitourinary tract among paracoccidioidomycosis patients is rare and even rarer when only the external genitalia are considered. As observed in the classical picture of paracoccidioidomycosis patients, the male gender and the chronic multifocal clinical form prevailed in the present study.

The influence of external ultrasound on the histologic architecture of the organic capsule around smooth silicone implants: Experimental study in rats

Background Capsular contracture is the main complication related to breast silicone implants, and its prevention remains a medical challenge. The authors present experimental research examining the effect of external ultrasound on the formation and contracture of peri-implant capsules.Methods In this study, 42 male Wistar rats had a 2-mm smooth surface implant placed in a dorsal submuscular pocket. They then were separated into ultrasound'' and control'' groups that received repeated external applications either with or without the ultrasound power on. Ultrasound applications were given three times a week for a period of 90 days. After that, both groups were housed under the same conditions with no application scheduled. Five animals of each group, killed at 30, 60, 90, and 180 days, had their implants removed along with the capsule, which received a special histologic preparation via annular sectioning that provided wide circumferential observation of the capsular tissue. Sections were stained with hematoxylin/eosin stain, Masson's trichrome stain, and Pricrosirius Red stain for regular microscopic evaluation under normal and polarized light.Results Histologic data showed that capsules from the ultrasound and control groups had statistically significant differences. Ultrasound application developed a capsular architecture similar to that shown within textured silicone implants, and its effect had an early definition with subsequent stabilization.Conclusion The authors conclude that early and repeated external ultrasound application enhances the thickness, cellular count, and vascularity of smooth silicone capsular tissue, whereas it diminishes the pattern of parallel orientation of collagen fibers.

Testicular fine needle aspiration cytology from a stallion with testicular degeneration after external genitalia trauma.

A seven-year-old Quarter Horse had a serious external genitalia trauma with severe swelling of ventrum, penis, prepuce and scrotum after falling over a fence. Appropriated treatment was rapidly started after clinical examination. During recovery period, the spermatogenesis assess by semen evaluation was not possible due to stallion's inability to ejaculate. Therefore, for testicular evaluation fine needle aspiration cytology (FNAC) was performed. The first FNAC showed a deviation of germ cell line towards immature cells, mainly by primary spermatocytes (59.5%) with very few late spermatids and spermatozoa (2.5% each), and an increased Sertoli cells/germ cells ratio (478/100), which characterized testicular degeneration. One month after the first FNAC, the second exam presented a drastic decrease of Sertoli cells/germ cells ratio (7/100) and marked increase of mature cell number, specially by early and late spermatids (50% and 24.5%, respectively). In this case, the results of both FNAC could demonstrate a partial recovery of spermatogenesis activity. Two months later, the stallion had mated two mares successfully and they became pregnant. In conclusion, the adequate treatment allowed a complete recovery of the stallion's reproductive function, and since semen collection was impossible during treatment, testicular FNAC showed to be an efficient diagnostic method for evaluating acute damage in the spermatogenesis.

Photoelastic Stress Analysis in Screwed and Cemented Implant-Supported Dentures With External Hexagon Implants

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

Periapical tissue reactions to calcium hydroxide and MTA after external root resorption as a sequela of delayed tooth replantation

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

Digital Radiographic Evaluation of the Level of Alveolar Bone Crest in External Hexagon Implants Submitted to 2 Types of Implant Abutments Under Immediate Loading

Purpose: The aim of this study was to evaluate by means of digital radiography the behavior of the alveolar bone crest in external hexagon implants following the use of 2 different types of abutments, one for conventional cemented prosthesis and one for modified cemented prosthesis.Methods: Ten external hexagon implants (platform 4.1) were placed in 5 patients. Initial instrumentation was carried out to obtain primary stability of the temporary prostheses under immediate loading. Each patient received both abutments for conventional and modified cemented prosthesis. Standardized digital periapical radiographies were performed at times T0 (immediately after implant placement) and T1 (4 months after implant placement). A straight line was initially established from the implant platform to the distal and mesial periimplantar marginal bone tissue (immediately in contact with the implant) and measured by digital radiography, using Sidexis version 2.3 (Sirona Dental Systems GmbH, Bensheim, Germany) software. The data were submitted to paired-samples t-test analysis.Results: There was no significant difference between the conventional and modified cemented prosthesis. In both cases, t-test results were within the null hypothesis level.Conclusion: The abutment for the modified cemented prosthesis resulted in no significant radiographic difference of alveolar bone crest height, when compared with the conventional cemented prostheses.

Comparative analysis of root surface smear layer removal by different etching modalities or erbium:yttrium-aluminum-garnet laser irradiation. A scanning electron microscopy study

The purpose of this study was to evaluate the effect of erbium:yttrium-aluminum-garnet (Er:YAG) laser (2.94 mu m) irradiation on the removal of root surface smear layer of extracted human teeth and to compare its efficacy with that of citric acid, ethylenediamine tetra-acetic acid (EDTA), or a gel containing a mixture of tetracycline hydrochloride (HCl) and citric acid, using scanning electron microscopy (SEM). Thirty human dentin specimens were randomly divided into six groups: G1 (control group), irrigated with 10 ml of physiologic saline solution; G2, conditioned with 24% citric acid gel; G3, conditioned with 24% EDTA gel; G4, conditioned with a 50% citric acid and tetracycline gel; G5, irradiated with Er:YAG laser (47 mJ/10 Hz/5.8 J/cm(2)/pulse); G6, irradiated with Er:YAG laser (83 mJ/10 Hz/10.3 J/cm(2)/pulse). Electron micrographs were obtained and analyzed according to a rating system. Statistical analysis was conducted with Kruskal-Wallis and Mann-Whitney tests (P < 0.05). G1 was statistically different from all the other groups; no statistically significant differences were observed between the Er:YAG laser groups and those undergoing the other treatment modalities. When the two Er:YAG laser groups were compared, the fluency of G6 was statistically more effective in smear layer removal than the one used in G5 (Mann-Whitney test, P < 0.01). Root surfaces irradiated by Er:YAG laser had more irregular contours than those treated by chemical agents. It can be concluded that all treatment modalities were effective in smear layer removal. The results of our study suggest that the Er:YAG laser can be safely used to condition diseased root surfaces effectively. Furthermore, the effect of Er:YAG laser irradiation on root surfaces should be evaluated in vivo so that its potential to enhance the healing of periodontal tissues can be assessed.

Preload Evaluation of Different Screws in External Hexagon Joint

Purpose: This study compared the maintenance of tightening torque in different retention screw types of implant-supported crowns.Materials and Methods: Twelve metallic crowns in UCLA abutments cast with cobalt-chromium alloy were attached to external hexagon osseointegrated implants with different retention screws: group A: titanium alloy retention screw; group B: gold alloy retention screw with gold coating; group C: titanium alloy retention screw with diamond-like carbon film coating; and group D: titanium alloy retention screw with aluminum titanium nitride coating. Three detorque measurements were obtained after torque insertion in each replica. Data were evaluated by analysis of variance (ANOVA), Tukey's test (P < 0.05), and t test (P < 0.05).Results: Detorque value reduced in all groups (P < 0.05). Group A retained the highest percentage of torque in comparison with the other groups (P < 0.05). Groups B and D retained the lowest percentage of torque without statistically significant difference between them (P < 0.05).Conclusions: All screw types exhibited reduction in the detorque value. The titanium screw maintained the highest percentage of torque whereas the gold-coated screw and the titanium screw with aluminum titanium nitride coating retained the lowest percentage. (Implant Dent 2012;21:46-50)

Biomechanical evaluation of internal and external hexagon platform switched implant-abutment connections: An in vitro laboratory and three-dimensional finite element analysis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

External control of the public water supply in 29 Brazilian cities

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of Nd:YAG Irradiation and Fluoride Application on Dentine Resistance to Erosion in Vitro

Objective: In this paper we evaluated the effect of two fluoridated agents and Nd:YAG irradiation separately and in combination on dentine resistance to erosion. Background Data: The morphological changes in dentin induced by laser treatment may reduce the progression of erosive lesions. Due to the possibility of a synergistic effect of laser with fluoride, this study was conducted. Materials and Methods: Eighty bovine dentine samples (4 x 4 mm) were randomly divided into eight groups, according to the following treatments: G1: untreated (control); G2: acidic phosphate fluoride gel (APF 1.23%) for 4 min; G3: fluoride varnish (NaF 2.26%) for 6 h; G4: 0.5 W Nd: YAG laser (250 mu sec pulse, 10 Hz, 35 J/cm(2), 30 sec); G5: 0.75 W Nd: YAG laser (52.5 J/cm(2)); G6: 1.0 W Nd: YAG laser (70 J/cm(2)); G7: APF + 0.75 W Nd: YAG laser; and G8: NaF + 0.75 W Nd: YAG laser. After the treatments, half of each dentine surface was protected with nail varnish. The samples were stored in artificial saliva (30 mL/sample) for 24 h and submitted to four erosive 1-min cycles. Between the erosive attacks, the blocks were maintained in artificial saliva for 59 min. The erosive wear was evaluated by profilometry. Results: The mean wear (+/- SD, mu m) was: G1: 1.20 +/- 0.20; G2: 0.47 +/- 0.06; G3: 0.81 +/- 0.11; G4: 1.47 +/- 0.32; G5: 1.52 +/- 0.24; G6: 1.49 +/- 0.30; G7: 0.49 +/- 0.11; and G8: 1.06 +/- 0.31 (Tukey's test, p < 0.05). Conclusions: Laser irradiation was not able to reduce dentine erosion. However, fluoride application was able to increase the dentine's resistance to erosion, and APF showed better results than fluoride varnish.

Increased Viability of Odontoblast-Like Cells Subjected to Low-Level Laser Irradiation

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

Effect of low-level laser irradiation on odontoblast-like cells

Low-level laser therapy (LLLT), also referred to as therapeutic laser, has been recommended for a wide array of clinical procedures, among which the treatment of dentinal hypersensitivity. However, the mechanism that guides this process remains unknown. Therefore, the objective of this study was to evaluate in vitro the effects of LLL irradiation on cell metabolism (MTT assay), alkaline phosphatase (ALP) expression and total protein synthesis. The expression of genes that encode for collagen type-1 (Col-1) and fibronectin (FN) was analyzed by RT-PCR. For such purposes, oclontoblast-like cell line (MDPC-23) was previously cultured in Petri dishes (15000 cells/cm(2)) and submitted to stress conditions during 12 h. Thereafter, 6 applications with a monochromatic near infrared radiation (GaAlAs) set at predetermined parameters were performed at 12-h intervals. Non-irradiated cells served as a control group. Neither the MTT values nor the total protein levels of the irradiated group differed significantly from those of the control group (Mann-Whitney test; p > 0.05). on the other hand, the irradiated cells showed a decrease in ALP activity (Mann-Whitney test; p < 0.05). RT-PCR results demonstrated a trend to a specific reduction in gene expression after cell irradiation, though not significant statistically (Mann-Whitney test; p > 0.05). It may be concluded that, under the tested conditions, the LLLT parameters used in the present study did not influence cell metabolism, but reduced slightly the expression of some specific proteins.