In vitro biomechanical comparison of six different fixation methods following 5-mm sagittal split advancement osteotomies

The sagittal split ramus osteotomy (SSRO) is a surgical technique used widely to treat many congenital and acquired mandibular discrepancies. Stabilization of the osteotomy site and the potential for skeletal relapse after the procedure are still major problems. The aim of this study was to compare the mechanical stability of six methods of rigid fixation in SSRO using a biomechanical test model. Sixty polyurethane replicas of human hemimandibles were divided into six groups. In group I, the osteotomies were fixed with two four-hole titanium miniplates; in group II, with one four-hole miniplate; in group III, with one four-hole miniplate + a bicortical screw; in group IV, with a grid miniplate; in group V, with a four-hole locking miniplate; and in group VI, with a six-hole miniplate. A linear load in the premolar region was applied to the hemimandibles. The resistance forces (N) needed to displace the distal segment by 1, 3, and 5 mm were recorded and the data transmitted from the load cell to a computer. One-way analysis of variance with Tukey's post hoc test was performed to compare the means between groups. For the three displacement conditions, there was a strong tendency for the 2.0-mm plate + screw and the grid plate to have higher values.

Burnout in dental students: effectiveness of different methods

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fecal collection methods for the determination of protein digestibility in bullfrogs

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

Computer graphics applied to anatomy: a study of two bio-cad modeling methods on finite element analysis of human edentulous hemi-mandible

Modeling is a step to perform a finite element analysis. Different methods of model construction are reported in literature, as the Bio-CAD modeling. The purpose of this study was to perform a model evaluation and application using two methods of Bio-CAD modeling from human edentulous hemi-mandible on the finite element analysis. From CT scans of dried human skull was reconstructed a stereolithographic model. Two methods of modeling were performed: STL conversion approach (Model 1) associated to STL simplification and reverse engineering approach (Model 2). For finite element analysis was used the action of lateral pterygoid muscle as loading condition to assess total displacement (D), equivalent von-Mises stress (VM) and maximum principal stress (MP). Two models presented differences on the geometry regarding surface number (1834 (model 1); 282 (model 2)). Were observed differences in finite element mesh regarding element number (30428 nodes/16683 elements (model 1); 15801 nodes/8410 elements (model 2). D, VM and MP stress areas presented similar distribution in two models. The values were different regarding maximum and minimum values of D (ranging 0-0.511 mm (model 1) and 0-0.544 mm (model 2), VM stress (6.36E-04-11.4 MPa (model 1) and 2.15E-04-14.7 MPa (model 2) and MP stress (-1.43-9.14 MPa (model 1) and -1.2-11.6 MPa (model 2). From two methods of Bio-CAD modeling, the reverse engineering presented better anatomical representation compared to the STL conversion approach. The models presented differences in the finite element mesh, total displacement and stress distribution.

Porosity and sealing ability of root fillings with gutta-percha and BioRoot RCS or AH Plus sealers. Evaluation by three ex vivo methods

To investigate the ability of BioRoot RCS, a tricalcium silicate-based root canal sealer and AH Plus to effectively fill the root canals of contralateral teeth using three evaluation methods, and to investigate also the correlation between the methods. The prepared root canals of ten pairs of contralateral mandibular premolar teeth were filled with gutta-percha and sealer using lateral compaction. The percentage of voids within the root canal was assessed by micro-computed tomography, whilst sealing ability was investigated by fluid transport and leakage of fluorescent microspheres. The interaction of sealer with dentine, and sealer penetration were assessed by confocal microscopy. The void volume, fluid flow, microsphere leakage and sealer interaction with dentine for both materials were compared. Nonparametric (Mann-Whitney) tests were used to compare the % void and fluid transport of the two sealers. Spearman correlation was used to assess the pairwise relationships between the techniques. The level of significance was set to 0.05. BioRoot RCS exhibited significantly more percentage of voids than AH Plus. There was no difference in fluid flow and microsphere penetration. BioRoot RCS exhibited a different pattern of sealer penetration and interaction with the dentine walls compared to AH Plus. For both materials, the pairwise correlations between the three techniques were close to zero, indicating weak relationships. MicroCT analysis revealed a higher void volume for BioRoot RCS. The other techniques did not show a difference between the sealing ability of the sealers. The correlation between the three ex vivo methods of assessment was weak demonstrating their complementarity rather than their concordance.

Doxycycline hyclate: a review of properties, applications and analytical methods

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

O efeito da ordenação e estrutura geométrica dos materiais PtSn/C e PdSn/C na eletrooxidação do glicerol em meio alcalino

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparison of screening methods for conductive hearing loss identification in children: low-cost proposal

Objective To evaluate the effectiveness of two screening methods (imitanciometry screening and questionnaire) to identify children at risk for conductive hearing loss, comparing this data with complete audiologic evaluation. Methods Of 507 children aged between three and six, 111 completed all procedures. The observational methods used were: imitanciometry screening, a questionnaire to identify risk factors for hearing loss and complete audiologic evaluation. Results obtained in the first two instruments were compared with results from complete audiologic evaluation (gold standard). From these comparisons, sensitivity and specificity, accuracy, positive and negative predictive values, and odds ratio were determined for the two screening methods and for the combination of both methods. Results The two methods applied in series (questionnaire and after imitanciometry screening) showed a greater odds ratio and better correlation between sensitivity and proportion of false-positives (ROC curve). Conclusion Combining the two tests in series improved screening accuracy. This combination was the best tool for identifying children at risk for conductive hearing loss.

Assessment of myocardial infarction by CT angiography and cardiovascular MRI in patients with cocaine-associated chest pain: a pilot study

Objectives: Cocaine is a commonly used illicit drug that leads to the most emergency department (ED) visits. Chest pain is the most common presentation, reported in 40% of patients. Our aim was to evaluate the incidence of previous myocardial infarction among young cocaine users (18-40 years) with cocaine-associated chest pain by the assessment of myocardial fibrosis by cardiovascular MRI. Second, we also intended to evaluate the coronary tree by CT angiography (CTA). Methods: 24 cocaine users (22 males) who frequently complained about cocaine-associated chest pain underwent CTA and cardiovascular MRI. Mean age of patients was 29.7 years and most of them (79%) had frequently used inhalatory cocaine. Results: The calcium score turned out to be positive in only one patient (Agatston=54). Among the coronary segments evaluated, only one patient had calcified plaques at the anterior descending coronary artery (proximal and medium segments). Assessment of regional ventricular function by the evaluation of 17 segments was normal in all patients. None of the patients showed myocardial delayed enhancement, indicative of myocardial fibrosis. CTA therefore confirmed the low cardiovascular risk of these patients, since most of them (96%) had no atherosclerosis detected by this examination. Only one patient (4%) had coronary atherosclerosis detected, without significant coronary stenosis. Conclusion: Cardiovascular MR did not detect the presence of delayed enhancement indicative of myocardial fibrosis among young cocaine users with low cardiovascular risk who had complained of cocaine-associated chest pain.

INTRAVITREAL INJECTION OF RANIBIZUMAB DURING CATARACT SURGERY IN PATIENTS WITH DIABETIC MACULAR EDEMA

Purpose: To investigate macular thickness and visual acuity changes after 1 intravitreal injection of 0.5-mg ranibizumab during phacoemulsification cataract surgery in eyes with diabetic macular edema refractory to laser treatment. Methods: Eleven eyes of 11 patients with diabetic macular edema refractory to modified Early Treatment Diabetic Retinopathy Study laser therapy received intravitreal during phacoemulsification cataract surgery. Comprehensive ophthalmic evaluation was performed preoperatively and at 1, 4, 8 +/- 1, and 12 +/- 2 weeks postoperatively. Main outcome measures included central subfield thickness and best-corrected Early Treatment Diabetic Retinopathy Study visual acuity. Results: Eleven patients completed the 12-week study visit. Mean central subfield thickness (+/- SEM) was 399.82 +/- 29.50 mu m at baseline and did not change significantly at any postoperative study visit (P > 0.05). Mean (+/- SEM) best-corrected Early Treatment Diabetic Retinopathy Study visual acuity was 0.95 +/- 0.13 logarithm of the minimum angle of resolution (20/200) at baseline and was significantly improved at Weeks 1 (0.38 +/- 0.13), 4 (0.38 +/- 0.11), 8 (0.35 +/- 0.08), and 12 (0.46 +/- 0.12) after treatment (P < 0.05). Conclusion: In this case series of patients with diabetic macular edema refractory to laser therapy, intravitreal ranibizumab administered during cataract surgery was associated with no significant change in central subfield thickness postoperatively. Significant improvement in best-corrected Early Treatment Diabetic Retinopathy Study visual acuity was observed after treatment, likely because of cataract removal. RETINA 32:1799-1803, 2012

Analysis by MRI of Residual Tumor After Radiofrequency Ablation for Early Stage Breast Cancer

OBJECTIVE. The objective of our study was to evaluate the effectiveness of MRI in the detection of possible residual lesions after radiofrequency ablation (RFA) in the treatment of breast cancer. SUBJECTS AND METHODS. We prospectively evaluated 14 patients who had undergone ultrasound-guided core biopsies diagnostic of invasive ductal carcinoma (IDC; range of diameters, 1.0-3.0 cm) and then ultrasound-guided percutaneous RFA with sentinel node biopsy as the primary treatment. Breast MRI was performed 1 week before RFA to evaluate tumor extension and again 3 weeks after RFA to verify the presence of possible residual lesions. Conventional surgical resection of the tumors was performed 1 week after RFA. The MRI findings were compared with histopathologic analyses to confirm the presence or absence of residual tumor. RESULTS. There was no residual enhancement in seven lesions on the postablation breast MRI scans. These findings were confirmed by negative histopathologic findings in the surgical specimens. The MRI scans of five patients showed small areas of irregular enhancement that corresponded to residual lesions. In the two remaining patients, we observed enhancement of almost the entire lesion, indicating that RFA had failed. CONCLUSION. Breast MRI is effective in detecting residual lesions after RFA in patients with IDC.

Duplications of BHLHA9 are associated with ectrodactyly and tibia hemimelia inherited in non-Mendelian fashion

Background Split-hand/foot malformation (SHFM)-also known as ectrodactyly-is a congenital disorder characterised by severe malformations of the distal limbs affecting the central rays of hands and/or feet. A distinct entity termed SHFLD presents with SHFM and long bone deficiency. Mouse models suggest that a defect of the central apical ectodermal ridge leads to the phenotype. Although six different loci/mutations (SHFM1-6) have been associated with SHFM, the underlying cause in a large number of cases is still unresolved. Methods High resolution array comparative genomic hybridisation (CGH) was performed in patients with SHFLD to detect copy number changes. Candidate genes were further evaluated for expression and function during limb development by whole mount in situ hybridisation and morpholino knock-down experiments. Results Array CGH showed microduplications on chromosome 17p13.3, a locus previously associated with SHFLD. Detailed analysis of 17 families revealed that this copy number variation serves as a susceptibility factor for a highly variable phenotype with reduced penetrance, particularly in females. Compared to other known causes for SHFLD 17p duplications appear to be the most frequent cause of SHFLD. A similar to 11.8 kb minimal critical region was identified encompassing a single gene, BHLHA9, a putative basic loop helix transcription factor. Whole mount in situ hybridisation showed expression restricted to the limb bud mesenchyme underlying the apical ectodermal ridge in mouse and zebrafish embryos. Knock down of bhlha9 in zebrafish resulted in shortening of the pectoral fins. Conclusions Genomic duplications encompassing BHLHA9 are associated with SHFLD and non-Mendelian inheritance characterised by a high degree of non-penetrance with sex bias. Knock-down of bhlha9 in zebrafish causes severe reduction defects of the pectoral fin, indicating a role for this gene in limb development.

Synthesis of supported metal nanoparticle catalysts using ligand assisted methods

The synthesis and characterization methods of metal nanoparticles (NPs) have advanced greatly in the last few decades, allowing an increasing understanding of structure-property-performance relationships. However, the role played by the ligands used as stabilizers for metal NPs synthesis or for NPs immobilization on solid supports has been underestimated. Here, we highlight some recent progress in the preparation of supported metal NPs with the assistance of ligands in solution or grafted on solid supports, a modified deposition-reduction method, with special attention to the effects on NPs size, metal-support interactions and, more importantly, catalytic activities. After presenting the general strategies in metal NP synthesis assisted by ligands grafted on solid supports, we highlight some recent progress in the deposition of pre-formed colloidal NPs on functionalized solids. Another important aspect that will be reviewed is related to the separation and recovery of NPs. Finally, we will outline our personal understanding and perspectives on the use of supported metal NPs prepared through ligand-assisted methods.

The aplication of land use and nighttime lights on the development of high-resolution emission inventories for South America

In this paper, nighttime light data are suggested as a proxy for spatial distribution of vehicles running in urban and nearby areas. Nighttime lights focus on human activities, in contrast to traditional Earth observing systems that focus on natural systems. It is the human activity being visible in the form of brightness of nocturnal lights. Two available nighttime lights dataset were used in this work. The first one was provided by the U.S. Air Force Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS), henceforth, DMSO-OLS. The second one is the NASA-NOAA Suomi National Polar-orbiting Polar-orbiting Partnership (NPP) satellite, henceforth, Suomi-NPP. To validate the new proposed methodology, hundreds of urban areas of South America were analyzed in a high degree of resolution. The results of this study showed that night-time lights are very well correlated with vehicle fleet, population, and impervious surfaces but with strong spatial variability. The results of this study suggest a better understanding of the human activities in the context of a vehicular-based city conception.

Characterization and modeling of the barrier properties in nanostructured systems

The object of the present study is the process of gas transport in nano-sized materials, i.e. systems having structural elements of the order of nanometers. The aim of this work is to advance the understanding of the gas transport mechanism in such materials, for which traditional models are not often suitable, by providing a correct interpretation of the relationship between diffusive phenomena and structural features. This result would allow the development new materials with permeation properties tailored on the specific application, especially in packaging systems. The methods used to achieve this goal were a detailed experimental characterization and different simulation methods. The experimental campaign regarded the determination of oxygen permeability and diffusivity in different sets of organic-inorganic hybrid coatings prepared via sol-gel technique. The polymeric samples coated with these hybrid layers experienced a remarkable enhancement of the barrier properties, which was explained by the strong interconnection at the nano-scale between the organic moiety and silica domains. An analogous characterization was performed on microfibrillated cellulose films, which presented remarkable barrier effect toward oxygen when it is dry, while in the presence of water the performance significantly drops. The very low value of water diffusivity at low activities is also an interesting characteristic which deals with its structural properties. Two different approaches of simulation were then considered: the diffusion of oxygen through polymer-layered silicates was modeled on a continuum scale with a CFD software, while the properties of n-alkanthiolate self assembled monolayers on gold were analyzed from a molecular point of view by means of a molecular dynamics algorithm. Modeling transport properties in layered nanocomposites, resulting from the ordered dispersion of impermeable flakes in a 2-D matrix, allowed the calculation of the enhancement of barrier effect in relation with platelets structural parameters leading to derive a new expression. On this basis, randomly distributed systems were simulated and the results were analyzed to evaluate the different contributions to the overall effect. The study of more realistic three-dimensional geometries revealed a prefect correspondence with the 2-D approximation. A completely different approach was applied to simulate the effect of temperature on the oxygen transport through self assembled monolayers; the structural information obtained from equilibrium MD simulations showed that raising the temperature, makes the monolayer less ordered and consequently less crystalline. This disorder produces a decrease in the barrier free energy and it lowers the overall resistance to oxygen diffusion, making the monolayer more permeable to small molecules.