Vitamin A Supplementation for Different Periods Alters Oxidative Parameters in Lungs of Rats

Matheus Augusto de Bittencourt Pasquali,Daniel Pens Gelain,Marcos Roberto de Oliveira,Guilherme Antônio Behr,Leonardo Lisbôa da Motta,Ricardo Fagundes da Rocha,Fábio Klamt,José Cláudio Fonseca Moreira 한국식품영양과학회 2009 Journal of medicinal food Vol.12 No.6

Lungs require an adequate supply of vitamin A (retinol) for normal embryonic development, postnatal maturation, and maintenance and repair during adult life. However, recent intervention studies revealed that supplementation with retinoids resulted in higher incidence of lung cancer, although the mechanisms underlying this effect are still unknown. Here, we studied the effect of vitamin A supplementation on oxidative stress parameters in lungs of Wistar rats. Vitamin A supplementation at either therapeutic (1,000 and 2,500IU/kg) or excessive (4,500 and 9,000IU/kg) doses for 3, 7, or 28 days induced lipid peroxidation, protein carbonylation, and oxidation of protein thiol groups, as well as change in catalase and superoxide dismutase activity. Together, these results suggest that vitamin A supplementation causes significant changes in redox balance, which are frequently associated with severe lung dysfunction.

A Seamless Flow Mobility Management Architecture for Vehicular Communication Networks

Meneguette, Rodolfo Ipolito,Bittencourt, Luiz Fernando,Madeira, Edmundo Roberto Mauro The Korea Institute of Information and Commucation 2013 Journal of communications and networks Vol.15 No.2

Vehicular ad-hoc networks (VANETs) are self-organizing, self-healing networks which provide wireless communication among vehicular and roadside devices. Applications in such networks can take advantage of the use of simultaneous connections, thereby maximizing the throughput and lowering latency. In order to take advantage of all radio interfaces of the vehicle and to provide good quality of service for vehicular applications, we developed a seamless flow mobility management architecture based on vehicular network application classes with network-based mobility management. Our goal is to minimize the time of flow connection exchange in order to comply with the minimum requirements of vehicular application classes, as well as to maximize their throughput. Network simulator (NS-3) simulations were performed to analyse the behaviour of our architecture by comparing it with other three scenarios. As a result of this work, we observed that the proposed architecture presented a low handover time, with lower packet loss and lower delay.

Finite element computational modeling of externally bonded CFRP composites flexural behavior in RC beams

André Luís Gamino,Túlio Nogueira Bittencourt,José Luiz Antunes de Oliveira e Sousa 사단법인 한국계산역학회 2009 Computers and Concrete, An International Journal Vol.6 No.3

This paper focuses on the flexural behavior of RC beams externally strengthened with Carbon Fiber Reinforced Polymers (CFRP) fabric. A non-linear finite element (FE) analysis strategy is proposed to support the beam flexural behavior experimental analysis. A development system(QUEBRA2D/FEMOOP programs) has been used to accomplish the numerical simulation. Appropriate constitutive models for concrete, rebars, CFRP and bond-slip interfaces have been implemented and adjusted to represent the composite system behavior. Interface and truss finite elements have been implemented (discrete and embedded approaches) for the numerical representation of rebars, interfaces and composites.

Finite element analysis of concrete cracking at early age

Aurich, Mauren,Filho, Americo Campos,Bittencourt, Tulio Nogueira,Shah, Surendra P. Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.37 No.5

The study of the early age concrete properties is becoming more important, as the thermal effects and the shrinkage, even in the first hours, could generate cracks, increasing the permeability of the structure and being able to induce problems of durability and functionality in the same ones. The detailed study of the stresses development during the construction process can be decisive to keep low the cracking levels. In this work a computational model, based on the finite element method, was implemented to simulate the early age concrete behavior and, specially, the evaluation of the cracking risk. The finite element analysis encloses the computational modeling of the following phenomena: chemical, thermal, moisture diffusion and mechanical which occur at the first days after the concrete cast. The developed software results were compared with experimental values found in the literature, demonstrating an excellent approach for all the implemented analysis.

Finite element analysis of concrete cracking at early age

Mauren Aurich,Américo Campos Filho,Túlio Nogueira Bittencourt,Surendra P. Shah 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.37 No.5

The study of the early age concrete properties is becoming more important, as the thermal effects and the shrinkage, even in the first hours, could generate cracks, increasing the permeability of the structure and being able to induce problems of durability and functionality in the same ones. The detailed study of the stresses development during the construction process can be decisive to keep low the cracking levels. In this work a computational model, based on the finite element method, was implemented to simulate the early age concrete behavior and, specially, the evaluation of the cracking risk. The finite element analysis encloses the computational modeling of the following phenomena: chemical, thermal, moisture diffusion and mechanical which occur at the first days after the concrete cast. The developed software results were compared with experimental values found in the literature, demonstrating an excellent approach for all the implemented analysis.

Effect of irrigation protocols on smear layer removal, bond strength and nanoleakage of fiber posts using a self-adhesive resin cement

Alessi Rodrigo Stadler,Jitumori Renata Terumi,Bittencourt Bruna Fortes,Gomes Giovana Mongruel,Gomes João Carlos 대한치과보존학회 2023 Restorative Dentistry & Endodontics Vol.48 No.3

Objectives This study aimed to investigate the effect of the application method of 2% chlorhexidine (CHX) and its influence on the adhesion of fiberglass posts cemented with a self-adhesive resin cement. Materials and Methods Sixty human mandibular premolars were endodontically treated and divided into 5 groups (n = 12), according to the canal irrigant and its application method: 2 groups with conventional syringe irrigation (CSI)—2.5% sodium hypochlorite (NaOCl) (control) and 2% CHX— and 3 groups with 2% CHX irrigation/activation—by passive ultrasonic irrigation (PUI), Easy Clean file, and XP-Endo Finisher file. Two roots per group were evaluated for smear layer (SL) removal by scanning electron microscopy. For other roots, fiber posts were luted using a self-adhesive resin cement. The roots were sectioned into 6 slices for push-out bond strength (BS) (7/group) and nanoleakage (NL) (3/group). Data from SL removal were submitted to Kruskal-Wallis and Student-Newman-Keuls tests (α = 0.05). Data from BS and NL were evaluated by 2-way analysis of variance and Tukey’s test (α = 0.05). Results For SL removal and BS, the CHX irrigation/activation promoted better values than CSI with CHX (p < 0.05), but it was not significantly different from CSI with NaOCl (p > 0.05). For NL, the lowest values were obtained by the chlorhexidine irrigation/activation groups (p < 0.05). Conclusions Active 2% CHX irrigation can be used to improve the post space cleaning and adhesion before fiber post cementation with self-adhesive resin cements. Objectives This study aimed to investigate the effect of the application method of 2% chlorhexidine (CHX) and its influence on the adhesion of fiberglass posts cemented with a self-adhesive resin cement. Materials and Methods Sixty human mandibular premolars were endodontically treated and divided into 5 groups (n = 12), according to the canal irrigant and its application method: 2 groups with conventional syringe irrigation (CSI)—2.5% sodium hypochlorite (NaOCl) (control) and 2% CHX— and 3 groups with 2% CHX irrigation/activation—by passive ultrasonic irrigation (PUI), Easy Clean file, and XP-Endo Finisher file. Two roots per group were evaluated for smear layer (SL) removal by scanning electron microscopy. For other roots, fiber posts were luted using a self-adhesive resin cement. The roots were sectioned into 6 slices for push-out bond strength (BS) (7/group) and nanoleakage (NL) (3/group). Data from SL removal were submitted to Kruskal-Wallis and Student-Newman-Keuls tests (α = 0.05). Data from BS and NL were evaluated by 2-way analysis of variance and Tukey’s test (α = 0.05). Results For SL removal and BS, the CHX irrigation/activation promoted better values than CSI with CHX (p < 0.05), but it was not significantly different from CSI with NaOCl (p > 0.05). For NL, the lowest values were obtained by the chlorhexidine irrigation/activation groups (p < 0.05). Conclusions Active 2% CHX irrigation can be used to improve the post space cleaning and adhesion before fiber post cementation with self-adhesive resin cements.

Improving site index estimates for pine and spruce plantations: a case study in the sub-boreal spruce zone in British Columbia

Christopher D.B. Hawkins,Amalesh Dhar,Eduardo Bittencourt 한국산림과학회 2013 Forest Science And Technology Vol.9 No.2

Site index (SI) expresses the growth potential for a species on a given site. Three SI determination methods were used for each managed stand sampled in the southern portion of the Prince George Timber Supply Area (TSA): forest inventory, calculated growth intercept or height over age, and site index biogeoclimatic ecosystem classification (SIBEC). Interior spruce and lodgepole pine leading stands were sampled in the Bowron Valley and only pine stands were sampled in the rest of the TSA. In the Bowron Valley for both species, calculated SI was greater than SIBEC SI, which was greater than inventory SI. Increases were greater for spruce. In the remaining pine areas sampled, the same relationship was observed. Pine yield model projections indicate mean annual increment (MAI) culmination occurred 5.7 and 16.4 years sooner for calculated SI compared with SIBEC and inventory SI, respectively, with yields increasing by 8% and 13%. The increases could be due to improved silviculture, tree response to climate change or a combination of the two. Differences could result in a mid-term timber supply available sooner or a greater yield at planned harvest age. This is particularly important in areas attacked by mountain pine beetle.

EVOLUTION OF MONETARY POLICY TRANSMISSION MECHANISM IN MALAWI: A TVP-VAR APPROACH

CHANCE NGAMANYA MWABUTWA,NICOLA VIEGI,MANOEL BITTENCOURT 중앙대학교 경제연구소 2016 Journal of Economic Development Vol.41 No.1

This paper investigates the evolution of monetary transmission mechanism in Malawi between 1981 and 2010 using a time varying parameter vector autoregressive (TVP-VAR) model with stochastic volatility. We evaluate how the responses of real output and general price level to bank rate, exchange rate and credit shocks have changed over time since Malawi adopted financial reforms in 1980s. It is becoming clear from literature that financial reforms can change the monetary transmission by changing the overall impact of the policy or by altering the transmission channels overtime. Therefore, the impact of monetary policy on price stability and output growth can vary and portray delayed effects overtime. The paper finds that inflation and real output responses to monetary policy shocks changed over the period under the review. Importantly, beginning mid-2000s, the monetary transmission performed consistently with predictions of economic theory partly due to stable macroeconomic conditions and positive structural changes in the economy. However, the statistical significance of the private credit supply remains weak and this calls for more financial reforms targeting the credit market which can contribute to monetary transmission and promote further economic growth in Malawi.

A Seamless Flow Mobility Management Architecture for Vehicular Communication Networks

Rodolfo Ipolito Meneguette,,Luiz Fernando Bittencourt,Edmundo Roberto Mauro Madeira 한국통신학회 2013 Journal of communications and networks Vol.15 No.2

Vehicular ad-hoc networks (VANETs) are selforganizing,self-healing networks which provide wireless communication among vehicular and roadside devices. Applications in such networks can take advantage of the use of simultaneous connections,therebymaximizing the throughput and lowering latency. In order to take advantage of all radio interfaces of the vehicle and to provide good quality of service for vehicular applications,we developed a seamless flow mobility management architecture based on vehicular network application classes with network-based mobility management. Our goal is to minimize the time of flow connection exchange in order to comply with the minimum requirements of vehicular application classes, as well as to maximize their throughput. Network simulator (NS-3) simulations were performed to analyse the behaviour of our architecture by comparing it with other three scenarios. As a result of this work, we observed that the proposed architecture presented a low handover time, with lower packet loss and lower delay.

The Influence of Levetiracetam in Cognitive Performance in Healthy Individuals: Neuropsychological, Behavioral and Electrophysiological Approach

Julio Cesar Magalhães,Mariana Gongora,Renan Vicente,Juliana Bittencourt,Guaraci Tanaka,Bruna Velasques,Silmar Teixeira,Gledys Morato,Luis F. Basile,Oscar Arias-Carrión,Fernando A.M.S Pompeu,Mauricio C 대한정신약물학회 2015 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.13 No.1

Objective: The present study sought to analyze the influence of Levetiracetam (LEV) in cognitive performance by identifying the changes produced by LEV in reaction time, in neuropsychological assessment of attention and memory and in absolute theta power in frontal activity. Methods: Twelve healthy subjects (5 men and 7 women; mean age, 30.08 years, standard deviation, 4.71) were recruited for this study. The neuropsychological tests: Trail Making Test (A and B), Digit Span (direct and indirect numerical orders/working memory); Stroop test (inhibitory control of attention); Tower of London (planning and decision-making) and a quantitative electroencephalography were applied in 2 different days after and before the participants ingested the capsule of placebo or 500 mg LEV. Results: A two-way-ANOVA was implemented to observe the interaction between conditions (placebo or LEV 500 mg) and moments (pre- and post-ingestion of LEV or placebo). The data were analyzed by the SPSS statistical package (p<0.05). For the neuropsychological parameter, the Trail Making Test (A) was the only test that showed significant difference for condition in the task execution time (p=0.026). Regarding the reaction time in the behavioral parameter, an interaction between both factors (p=0.034) was identified through a two-way-ANOVA (condition versus moment). Electrophysiological measures showed a significant interaction for electrodes: F7, F3, and FZ. Conclusion: The findings showed that LEV promotes an important cognitive enhancement in the executive functions.