Thermodynamic and electronic study of Ga-1 _ xMnxN films. A theoretical study

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

Thermoanalytical study of purine derivatives compounds

Os métodos térmicos em análises estão sendo atualmente muito utilizados nas investigações cientificas. Neste trabalho a termogravimetria-análise térmica diferencial simultânea (TG-DTA), difratometria de raios X pelo método do pó, espectroscopia de absorção na região do infravermelho foram utilizadas para estudar os compostos derivados da purina. Sendo estes: aminofilina. teofilina, cafeína e ácido úrico. Os resultados forneceram informações com respeito à estabilidade térmica e decomposição térmica sobre esses compostos.

Thermal stability and thermal decomposition of sucralose

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

Stability and convergence analysis of a neural model applied in nonlinear systems optimization

A neural model for solving nonlinear optimization problems is presented in this paper. More specifically, a modified Hopfield network is developed and its internal parameters are computed using the valid-subspace technique. These parameters guarantee the convergence of the network to the equilibrium points that represent an optimal feasible solution. The network is shown to be completely stable and globally convergent to the solutions of nonlinear optimization problems. A study of the modified Hopfield model is also developed to analyze its stability and convergence. Simulation results are presented to validate the developed methodology.

Attitude stability of artificial satellites subject to gravity gradient torque

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

On the stability of the satellites of asteroid 87 Sylvia

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

Temporal stability for unpredictable annual climatic variability for Hevea genotype selection

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

A study of the effect of hemorrhage on the cardiorespiratory actions of halothane, isoflurane and sevoflurane in the dog

Objective To compare the cardiorespiratory changes induced by equipotent concentrations of halothane (HAL), isoflurane (ISO) and sevollurane (SEVO) before and after hemorrhage.Study design. Prospective, randomized clinical trial.Animals. Twenty-four healthy adult dogs weighing 15.4 +/- 3.4 kg (mean +/- SD).Methods. Animals were randomly allocated to one of three groups (n = 8 per group). In each group, anesthesia was maintained with 1.5 minimum alveolar concentration of HAL (1.3%), ISO (1.9%,) and SEVO (3.5%) in oxygen. Controlled ventilation was performed to maintain eucapnia. Cardiorespiratory variables were evaluated at baseline (between 60 and 90 minutes after induction), immediately after and 30 minutes after the withdrawal of 32 mL kg(-1) of blood (400% of the estimated blood volume) over a 30-minute period.Results. During baseline conditions, ISO and SEVO resulted in higher cardiac index (CI) than HAL. Heart rates were higher with SEVO at baseline. while mean arterial pressure (MAP) and mean pulmonary arterial pressure did not differ between groups. Although heart rate values were higher for ISO and SEVO after hemorrhage, only ISO resulted in a higher CI when compared with HAL. In ISO-anesthetized dogs, MAP was higher immediately after hemorrhage, and this was related to better maintenance of CI and to an increase in systemic vascular resistance index from baseline.Conclusions. Although the hemodynamic responses of ISO and SEVO are similar in normovolaemic dogs, ISO results in better maintenance of circulatory function during the early period following a massive blood loss. Clinical relevance Inhaled anesthetics should be used judiciously in animals presented with blood loss. However, if an inhalational agent is to be used under these circumstances, ISO may provide better hemodynamic stability than SEVO or HAL.

Comparative study between target-controlled-infusion and continuous-infusion anesthesia in dogs treated with methotrimeprazine and treated with propofol and remifentanil

OBJETIVO: Comparar duas técnicas de infusão de propofol em cadelas submetidas à ovariohisterectomia, estudando a eficácia da dose alvo de propofol, avaliando os atributos cardiorrespiratórios, hemogasométricos e escala do índice bispectral, (BIS) bem como as características do período de recuperação. MÉTODOS: Foram anestesiadas 20 cadelas, distribuídos em dois grupos (GI e GII). em GI, os animais foram pré-tratados com levomepromazina e anestesiados com propofol por infusão alvo controlada, através de bomba de infusão Harvard pump, associado com remifentanila, através de bomba de seringa. em GII, os animais receberam o mesmo tratamento de GI, só que ao invés de receberem o propofol por infusão alvo controlada, receberam o propofol em infusão contínua de velocidade fixa. RESULTADOS: Bradicardia e discreta hipotensão, estabilidade hemogasométrica e respiratória, além de um bom miorrelaxamento, mais evidente na infusão contínua e boa hipnose. CONCLUSÕES: As doses de propofol utilizadas em ambas as técnicas, após o pré-tratamento de levomepromazina e associadas ao opióide, foram eficazes para a realização cirúrgica. A técnica de anestesia alvo controlada obteve um menor consumo de anestésico (propofol) com períodos mais rápidos de recuperação.

Compromised Primary Implant Stability

The aim of this study was to evaluate implants installed with compromised primary stability associated or not with polylactide and polyglycolide copolymer (PLA/PGA). Two 0.4-mm overdrilled defects (3 mm in diameter and 6 mm long) were produced in the right tibia of 25 rabbits. Half of the defects were left untreated, and the other half was filled with PLA/PGA. Implants of 2.6 mm in diameter and 6 mm long were placed into all defects. Animals were killed at 5, 15, 40, and 60 postoperative days, and biomechanical analysis (torque-reverse), histomorphometry, and immunohistochemistry (osteoprotegerin, receptor activator of NFJB ligand [RANKL], osteocalcin, and collagen-1 [ COL- I] staining) were performed. All the implants achieved osseointegration. There were no statistically significant differences in the torque-reverse and in linear contact extension between bone tissue and implant surface and no statistically significant difference in osteoprotegerin, RANKL, osteocalcin, and collagen-1 expression between the studied groups in all studied periods (P > 0.05). We can conclude that osseointegration can occur in compromised primary implant stability situations, and the addition of PLA/PGA did not improve the osseointegration process in this experimental model.

COLOR STABILITY of SEALED COMPOSITE RESIN RESTORATIVE MATERIALS AFTER ULTRAVIOLET ARTIFICIAL AGING and IMMERSION IN STAINING SOLUTIONS

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

Effect of Chemical Disinfection and Accelerated Aging on Color Stability of Maxillofacial Silicone with Opacifiers

Purpose: The purpose of this study was to evaluate the color stability of MDX4-4210 maxillofacial elastomer with opacifier addition submitted to chemical disinfection and accelerated aging.Materials and Methods: Ninety specimens were obtained from Silastic MDX4-4210 silicone. The specimens were divided into three groups (n = 30): Group I: colorless, Group II: barium sulfate opacifier, Group III: titanium dioxide opacifier. Specimens of each group (n = 10) were disinfected with effervescent tablets, neutral soap, or 4% chlorhexidine gluconate. Disinfection was conducted three times a week for 2 months. Afterward, the specimens were submitted to different periods of accelerated aging. Color evaluation was carried out after 60 days (disinfection period) and after 252, 504, and 1008 hours of accelerated aging, using a reflection spectrophotometer. Color alterations were calculated by the CIE L*a*b* system. Data were analyzed by three-way ANOVA and Tukey test (alpha = 0.05).Results: Group II exhibited the lowest color change, whereas Group III the highest (p < 0.05), regardless of the chemical disinfection and accelerated aging periods.Conclusion: Opacifier addition, chemical disinfection, and accelerated aging procedures affected the color stability of the maxillofacial silicone.

Effect of polymerization and accelerated aging on iris color stability of ocular prosthesis

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

Influence of Pigments and Opacifiers on Color Stability of an Artificially Aged Facial Silicone

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

Effect of Disinfection and Accelerated Aging on Color Stability of Colorless and Pigmented Facial Silicone

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)