Interspecies variation in orbital bone structure of psittaciform birds (with emphasis on Psittacidae)

Objectives: This text presents an anatomical study of the normal bony orbital structure of a sample of different bird species belonging to the order Psittaciformes.Procedures: the bony anatomy of Psittaciformes' skulls was examined and described using cadavers of birds that were presented already dead to the Federal University of Parana, Brazil or had been euthanized for humane reasons. Dissections of the orbital cavity were performed under 2-4 x magnification, and descriptions of the orbital bones were made from observations of macerated skulls that had been boiled and cleaned. The present paper discusses the main features of the bony orbit of psittaciform birds, describing known anatomical information but also bringing new information, mainly concerning species differences that might help not only veterinary anatomists but also zoologists, clinicians, researchers, and students of veterinary ophthalmology to better comprehend this order of birds.Results and conclusions: Variations in the anatomic conformation of the bony elements of the orbit were observed in different species of Psittaciformes. Based on these differences, Psittaciformes were classified into two different groups. The first group of Psittaciformes shows an enclosed (complete) bony orbit formed by the junction of the orbital with the postorbital processes, creating a suborbital arch. The second group of Psittaciformes essentially lacked a suborbital arch, presenting an open (incomplete) bony orbit, typical of most modern birds. In the latter group, orbital and postorbital processes are present.

Charge-orbital ordering and phase separation in the two-orbital model for manganites: Roles of Jahn-Teller phononic and Coulombic interactions

The main properties of realistic models for manganites are studied using analytic mean-field approximations and computational numerical methods, focusing on the two-orbital model with electrons interacting through Jahn-Teller (JT) phonons and/or Coulombic repulsions. Analyzing the model including both interactions by the combination of the mean-field approximation and the exact diagonalization method, it is argued that the spin-charge-orbital structure in the insulating phase of the purely JT-phononic model with a large Hund couphng J(H) is not qualitatively changed by the inclusion of the Coulomb interactions. As an important application of the present mean-held approximation, the CE-type antiferromagnetic state, the charge-stacked structure along the z axis, and (3x(2) - r(2))/(3y(2) - r(2))-type orbital ordering are successfully reproduced based on the JT-phononic model with large JH for the half-doped manganite, in agreement with recent Monte Carlo simulation results. Topological arguments and the relevance of the Heisenberg exchange among localized t(2g) spins explains why the inclusion of the nearest-neighbor Coulomb interaction does not destroy the charge stacking structure. It is also verified that the phase-separation tendency is observed both in purely JT-phononic (large JH) and purely Coulombic models in the vicinity of the hole undoped region, as long as realistic hopping matrices are used. This highlights the qualitative similarities of both approaches and the relevance of mixed-phase tendencies in the context of manganites. In addition, the rich and complex phase diagram of the two-orbital Coulombic model in one dimension is presented. Our results provide robust evidence that Coulombic and JT-phononic approaches to manganites are not qualitatively different ways to carry out theoretical calculations, but they share a variety of common features.

Treatment of radius, ulna and humerus fractures with the aid of a bone morphogenetic protein in a giant anteater (Myrmecophaga tridactyla)

A giant anteater (Myrmecophaga tridactyla) was found with closed comminuted fractures on the fight radius and ulna and left humerus he duration of which was unknown. The animal was unable to use either of he thoracic limbs. The fractures were stabilized with 3.5-mm titanium plates and a commercially available mixture of micro lyophilized bovine cortical osseous and bovine BMP (Gen-tech(R), Baumer, Brazil) was implanted into the fractures sites. Postoperative radiographic evaluations were performed every 30 days and after four months. Bone healing was observed in all of he fractures. The animal was able to be reintroduced into its natural habitat. From his case we conclude that despite he low metabolic fate of the giant anteater, which is an inherent characteristic of this species, he treatment of radius, ulna and humerus fractures by means of plates and screws, associated with BMP on the Myrmecophaga tridactyla, was a success.

Spin, charge, and orbital correlations in the one-dimensional t(2g)-orbital Hubbard model

We present the zero-temperature phase diagram of the one-dimensional t(2g)-orbital Hubbard model, obtained using the density-matrix renormalization group and Lanczos techniques. Emphasis is given to the case of the electron density n=5 corresponding to five electrons per site, while several other cases for electron densities between n=3 and 6 are also studied. At n=5, our results indicate a first-order transition between a paramagnetic (PM) insulator phase, with power-law slowly decaying correlations, and a fully polarized ferromagnetic (FM) state by tuning the Hund's coupling. The results also suggest a transition from the n=5 PM insulator phase to a metallic regime by changing the electron density, either via hole or electron doping. The behavior of the spin, charge, and orbital correlation functions in the FM and PM states are also described in the text and discussed. The robustness of these two states against varying parameters suggests that they may be of relevance in quasi-one-dimensional Co-oxide materials, or even in higher dimensional cobaltite systems as well.

Structural deformation monitored by vibrational properties and orbital modeling in (Pb,Sm)TiO3 systems

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Epidemiologic Evaluation of Mandibular Fractures in the Rio de Janeiro High-Complexity Hospital

The aim of this study was to gather data on trauma etiology and mandibular fracture localization in patients who presented at the General Hospital of Nova Iguacu, Rio de Janeiro, Brazil. From March 2007 to December 2008, 95 patients with mandibular fracture were registered in a medical form, at the Bucomax-illofacial Surgery Department of the General Hospital of Nova Iguacu, Rio de Janeiro, Brazil. Concerning mandibular fracture etiology, 21.05% were caused by motorcycle accidents, followed by interpersonal violence without use of weapons (punches, kicks, bumps with the head, blows with the elbow, etc) (16.84%) and interpersonal violence with firearm (14.73%). It was found that 52.63% of the patients had a single fracture line. The most affected fracture area was the parasymphysis (26.02%), followed by the condyle (22.60%) and mandibular angle (18.49%). Concerning the injury area, 24.21% were directed to the mandibular symphysis, 22.17% of the patients did not remember the injury area, and 18.94% had multiple injuries. When the injury was directed to the symphysis, the result was more condyle fractures (11.64%), and injuries at the mandibular angle resulted in fractures at the angle itself (8.90%). The most common fracture cause was traffic accidents, mainly motorcycle accidents, and the most affected areas were the parasymphysis and the condyle. The mandible isolated fractures occurred in half of the cases. Motorcycle accidents resulted in more fractures in the parasymphysis area, and when the symphysis area is affected by injuries, the result is a higher percentage in condyle fractures.

Synthesis Pengo System plates for the treatment of long-bone diaphyseal fractures in dogs

A Brazilian orthopaedic company designed a stainless steel plate called Synthesis Pengo System (S.P.S.), which has one fixed and one changeable extremity. According to the assembly of the changeable extremity, it is possible to obtain dynamization or neutralization of the fracture site. Since the S.P.S. plate was developed for use in human patients, the aim of this study was to evaluate this system in long-bone diaphyseal fractures in dogs. Eight dogs with closed diaphyseal fractures of the femur (n = 1), radius and ulna (n = 5), and tibia (n = 2) were used. Patients were aged seven months to three years and weighed 18 to 31.2 kg. The S.P.S. plate was assembled with one fixed extremity and one changeable extremity in dynamization mode. The trail bar was positioned for synthesis modules with holes for cortical screws. The modules were positioned close to one another in two fractures and for away from the fracture site in the others. The bone healing occurred by external callus. Since motion at the fracture site determines the amount of callus required, the secondary bone healing that was observed in all of the cases indicated less rigid fixation of this system. A potential benefit of this system was a lesser interface contact with the bone since it was only done by trail bar. The major disadvantage was the prominence of the implant. It was possible to conclude that the S.P.S. plate appears to be a suitable method for the treatment of diaphyseal fractures in dogs.

Treatment of traumatized permanent incisors with crown and root fractures: A case report

A case report of the treatment of permanent incisors with crown and root fractures is presented. A radiolucent lesion at the fracture lines was treated with calcium hydroxide in the coronal fragments for 18 months. Clinically, the teeth became firm and the radiographic results after 2 years showed healing of the lesion and hard tissue filling in the space at the fracture lines. © Munksgaard, 2001.

Resistance to maxillary premolar fractures after restoration of class II preparations with resin composite or ceromer.

OBJECTIVE: The aim of this study was to evaluate the resistance to fracture of intact and restored human maxillary premolars. METHOD AND MATERIALS: Thirty noncarious human maxillary premolars, divided into three groups of 10, were submitted to mechanical tests to evaluate their resistance to fracture. Group 1 consisted of intact teeth. Teeth in group 2 received mesio-occlusodistal cavity preparations and were restored with direct resin composite restorations. Teeth in group 3 received mesio-occlusodistal cavity preparations and were restored with ceromer inlays placed with the indirect technique. After restoration, teeth were stored at 37 degrees C for 24 hours and then thermocycled for 500 cycles at temperatures of 5 degrees C and 55 degrees C. RESULTS: Statistical analysis revealed that group 3 (178.765 kgf) had a significantly greater maximum rupture load than did group 1 (120.040 kgf). There was no statistically significant difference between groups 1 and 2 or between groups 2 and 3. CONCLUSION: Class II cavity preparations restored with indirect ceromer inlays offered greater resistance to fracture than did intact teeth. The fracture resistance of teeth restored with resin composite was not significantly different from that of either the ceromer or intact teeth.

Rigid internal fixation with titanium versus bioresorbable miniplates in the repair of mandibular fractures in rabbits

The purpose of this study was to compare by qualitative histology the efficacy of rigid internal fixation with titanium system and the Lacto Sorb® system in mandibular fractures in rabbits. Thirty male adult rabbits Oryctolagus cuniculus were used. Unilateral mandibular osteotomies were performed between the canine and first premolar. The animals were divided into two groups: for Group I - rigid internal fixation was performed with titanium system 1.5 mm (Synthes, Oberdorf, Switzerland), with two screws of 6 mm (bicortical) on each side of the osteotomy. For Group II-rigid internal fixation was performed with PLLA/PGA system 1.5 mm (Lacto Sorb®, WLorenz, Jacksonville, FL, USA). The histological analysis evaluated the presence of inflammatory reaction, degree of bone healing and degree of resorption of the Lacto Sorb® screws. The results of both fixation systems were similar, only with a small difference after 15 and 30 days. In Group I a faster bony healing was noted. But after 60 days, bony healing was similar in both groups. It is concluded that both PLLA/PGA and titanium plates and screws provide sufficient strength to permit mandibular bone healing. The resorption process of PLLA/PGA osteosynthesis material did not cause acute or chronic inflammatory reaction or foreign body reaction during the studied period. © 2004 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Peri-orbital bone dimensional analysis using computed tomography for placement of osseointegrated implants

Craniofacial osseointegrated implants enabled producing implant-retained facial prosthesis, namely the orbital prosthesis. Aim: To evaluate the length and width of the bone structure of the peri-orbital region and to present the method validation. Methods: Computed tomography scans of 30 dry human skulls were obtained in order to register linear length and width measurements of the periorbital region. Two examiners made the measurements twice with intervals of at least 7 days between them. Data were analyzed by descriptive statistics and the paired Student's t-test was used as inferential technique (SAS, α =0.05). Results: In most cases, the intra- and inter-examiner variations were not significant (p>0.05). Therefore, the method proposed was considered as precise and valid for the measurement of the peri-orbital region. The measured points correspond to the hours of a clock. The major lengths were observed at 1 h (18.32 mm) for the left peri-orbital bone and at 11h (19.28 mm) for the right peri-orbital bone, followed by the points situated at 2h (13.05 mm) and 12h (11.37 mm) for the left side and at 10 h (12.34 mm) and 12 h (11.56 mm) for the right side. It was verified that the three points with lowest values followed the same anatomical sequence in the supraorbital rim for the right and left orbits, showing compatibility with the insertion of the intraoral osseointegrated implants. The medial wall of both orbits did not present sufficient length to allow the insertion of intraoral or craniofacial implants. Conclusions: The largest width points were observed in the supraorbital rim and in the infralateral region of both orbits and those of smallest width were found in the supralateral region of both orbits.

Complete denture wearing and fractures among edentulous patients treated in university clinics

Objective: The prevalence of wearing and fracture of complete dentures was evaluated among edentulous patients treated in two dental schools in Brazil. Background: Acceptance and wearing of complete dentures are related to adaptive behaviour of edentulous patients. However, one reason that could interfere with the wearing dentures is their potential to fracture, which is still a common complication in denture rehabilitation practice. Material and methods: Two hundred and twenty-four edentulous patients rehabilitated with complete dentures from 2000 to 2005 in Araçatuba and Araraquara Dental School, University of State of São Paulo, were assessed in 2006 and 2007 to answer a questionnaire about wearing and fracture of their dentures. Statistical analysis were performed using Epi Info software and chi-squared test to compare maxillary and mandibular data (α = 0.05). Results: Almost 26% of the patients did not wear their dentures, and among the remainder, the majority wore the maxillary denture. About 30% of the dentures were fractured, with higher prevalence in the maxillary arch (p = 0.003). Conclusions: Discontinuation of wearing dentures was quite high, especially considering the treatment which was carried out in university clinics. Prevalence of fractures was also high, greater for the maxillary denture, and was one of the main reasons for non-wearing of complete dentures. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

Determination of onboard coplanar orbital maneuvers with orbits determined using GPS

In the present paper a study is made in order to find an algorithm that can calculate coplanar orbital maneuvers for an artificial satellite. The idea is to find a method that is fast enough to be combined with onboard orbit determination using GPS data collected from a receiver that is located in the satellite. After a search in the literature, three algorithms are selected to be tested. Preliminary studies show that one of them (the so called Minimum Delta-V Lambert Problem) has several advantages over the two others, both in terms of accuracy and time required for processing. So, this algorithm is implemented and tested numerically combined with the orbit determination procedure. Some adjustments are performed in this algorithm in the present paper to allow its use in real-time onboard applications. Considering the whole maneuver, first of all a simplified and compact algorithm is used to estimate in real-time and onboard the artificial satellite orbit using the GPS measurements. By using the estimated orbit as the initial one and the information of the final desired orbit (from the specification of the mission) as the final one, a coplanar bi-impulsive maneuver is calculated. This maneuver searches for the minimum fuel consumption. Two kinds of maneuvers are performed, one varying only the semi major axis and the other varying the semi major axis and the eccentricity of the orbit, simultaneously. The possibilities of restrictions in the locations to apply the impulses are included, as well as the possibility to control the relation between the processing time and the solution accuracy. Those are the two main reasons to recommend this method for use in the proposed application.

Prospective study of postoperative sensory disturbances after surgical treatment of mandibular fractures

Introduction: This present study's purpose is to evaluate the degree of paresthesia and recovery of inferior alveolar nerve in patients with mandible fractures who underwent surgical treatment. Material and methods: Nineteen patients were evaluated (27 hemimandibles) at six different times: preoperative (T1), postoperative 1 week (T2), postoperative 1 month (T3), postoperative 3 months (T4), postoperative 6 months (T5), and postoperative 1 year (T6). Subjective and objective methods were used for this evaluation. Results: The results were analyzed using likelihood ratio chi-square test for the hypothesis of no association between indicators of sensitivity and responses to the questionnaire, and the Cochran-Mantel-Haenszel test for equality hypothesis. All objective tests showed a statistically significant worsening in sensitivity at T2 (p < 0. 0001) and a significant improvement after T4 (α < 0. 05). The subjective tests showed an association with the objectives tests, and improvement in sensitivity after T4 (p < 0. 0001) was noted. Discussion: The first postoperative week is the period in which there are major changes with respect to sensitivity, and after 3 months postoperatively, the recovery reaches its apex with little difference observed after this period. In this research 100 % of the patients analyzed recovered all sensibility until T6. © 2012 Springer-Verlag.