Papers by Rafael Oliveira
Brazilian Journal of Infectious Diseases, 2007
This study aimed to test in vitro a RNA-interference based antiviral approach for rabies with sho... more This study aimed to test in vitro a RNA-interference based antiviral approach for rabies with short-interfering RNAs (siRNAs) against rabies virus nucleoprotein mRNA. BHK-21 cells were infected with serial dilutions of PV rabies virus strain and transfected with a pool of three siRNAs. Direct immunofluorescence staining showed a 5-time decrease in virus titer when compared to a non-treated plate, showing a promising new approach to the development of antivirals for rabies treatment.
Neotropical Ichthyology, 2007
Fish passages are constructed with the aim of reestablishing connectivity between critical habita... more Fish passages are constructed with the aim of reestablishing connectivity between critical habitats, in order to sustain those species that move over a large area during their lives. The upstream movements of most of the known migratory species are made for purposes of reproduction (adults) or dispersal (juveniles). The present study was conducted at the ladder constructed at Lajeado Dam (Luis Eduardo Magalhães Hydroelectric Power), on the Tocantins River. The objective was to assess whether there is a temporal pattern in the abundance of fish below the dam and in the ladder, that correlates with their breeding seasons. Additionally, it was examined whether reproduction is the predominant motivation of the shoals of fish that ascend the ladder. Samples were taken monthly from November, 2002 through October, 2003, downriver from the dam with gillnets, and in the resting pools of the fish ladder with cast nets. The analysis of seasonality in the aggregation of the shoals was based on the temporal variations in abundance and species richness. The possibility of a reproductive motivation for ascending the ladder was inferred from the frequency of the stages of gonadal development. However, during the entire study period we observed a high frequency of individuals with gonads in the pre-vitellogenic stage for all analyzed species, both downriver from the dam (97%) and in the fish ladder (98%). These findings suggest that there was no reproductive motivation for the aggregation of the fish downstream and for their entry into the ladder. On the other hand, the dominance of these stages downriver suggests that the spawning habitats are distant, and that the upstream movements occur for other reasons such as dispersal and search for more appropriate habitats for feeding and growth. The entrance into the ladder resulted more from rheophilic behavior, which is more pronounced in migratory species, than from an endogenous motivation linked to reproductive migration.
Biophysical Journal, 2002
Lipid lateral organization is increasingly found to modulate membrane-bound enzymes. We followed ... more Lipid lateral organization is increasingly found to modulate membrane-bound enzymes. We followed in real time the reaction course of sphingomyelin (SM) degradation by Bacillus cereus sphingomyelinase (SMase) of lipid monolayers by epifluorescence microscopy. There is evidence that formation of ceramide (Cer), a lipid second messenger, drives structural reorganization of membrane lipids. Our results provide visual evidence that SMase activity initially alters surface topography by inducing phase separation into condensed (Cer-enriched) and expanded (SM-enriched) domains. The Cer-enriched phase grows steadily as the reaction proceeds at a constant rate. The surface topography derived from the SMase-driven reaction was compared with, and found to differ from, that of premixed SM/Cer monolayers of the same lipid composition, indicating that substantial information content is stored depending on the manner in which the surface was generated. The long-range topographic changes feed back on the kinetics of Smase, and the onset of condensed-phase percolation is temporally correlated with a rapid drop of reaction rate. These observations reveal a bidirectional influence and communication between effects taking place at the local molecular level and the supramolecular organization. The results suggest a novel biocatalytictopographic mechanism in which a surface enzymatic activity can influence the function of amphitropic proteins important for cell function.
Journal of Periodontology, 2007
Introduction: Due to penetration of pathogenic bacteria into the periodontal tissues in moderate ... more Introduction: Due to penetration of pathogenic bacteria into the periodontal tissues in moderate to severe periodontitis, the mechanical methods are not sufficient in these cases. Therefore, administration of local/systemic antibiotic is recommended following mechanical root debridement. However, side effects of antibiotics such as microbial resistance and patient allergy led to development of alternative methods. One of the suggested methods is the antimicrobial photodynamic therapy (aPDT). aPDT is a local non invasive treatment modality without the side effects caused by antibiotics. The aim of this study was to collect the clinical articles related to the application of aPDT in the treatment of chronic periodontitis. Method: In order to find related clinical articles, a search of PubMed, Google Scholar and Science Direct until 2012 was performed. Results: A total of 11 articles were found. In 7 of the 11 articles, the assessment of aPDT led to a significant improvement in the clinical attachment and probing depth. In 4 studies, there was no difference between the scaling & root planing (SRP) and adjunctive application of aPDT. aPDT in most cases resulted in less gingival bleeding compare to SRP alone. Furthermore, its application in multiple doses was more effective in comparison to a single dose treatment.
Neurochemical Research, 2000
Myelin lipids form liquid-expanded monolayers at the air-water interface, with no evidence of sur... more Myelin lipids form liquid-expanded monolayers at the air-water interface, with no evidence of surface pressure-induced two-dimensional phase transition. However, the film doped with 2 mole % of the fluorescent probe N-(7-nitro-2-1,3-benzoxadiazol-4-yl) Diacyl Phosphatidyl-ethanolamine (NBD-PE) shows an irregular pattern of coexisting laterally segregated surface domains with diffuse boundaries that change from smooth patterns to fractal-like structures depending on surface pressure. Successive expansion-recompression cycles lead to more defined domains, with a general reorganization occurring at surface pressures of about 20 mN/m. At least two coexisting phases occur over almost all the compression isotherms. The presence of proteins in whole myelin monolayers induces defined domain textures with relatively sharp boundaries. The patterns during compression and expansion are quite similar and, after the first cycle, little changes occur under recompression. The patterns observed provide topographical evidence for the existence of dynamic domain microheterogeneity in the surface of myelin interfaces.
Biochimica Et Biophysica Acta-biomembranes, 1998
Myelin can be spread as a stable monomolecular layer, with reproducible properties, at the air-wa... more Myelin can be spread as a stable monomolecular layer, with reproducible properties, at the air-water interface. The major lipids and proteins of myelin are represented in this monolayer in molar ratios similar to those in the original membrane. A well-defined collapse point of the myelin monolayer occurs at ca. 46 mNrm. At a surface pressure of ca. 20 mNrm, the surface pressure-molecular area isotherm of the myelin monolayer shows a change in its compressibility, exhibited as a diffuse but reproducible inflection with a clearly marked change of the surface compressional modulus; the surface potential-area curve shows a change of slope at the same surface pressure. The myelin monolayer shows considerable hysteresis during the first compression-decompression cycle; no detectable protein unfolding under expansion; and decreased hysteresis after the first cycle. The average molecular areas, the inflection at 20 mNrm, the variation of the surface potential per unit of molecular surface density, and the hysteresis properties of the myelin monolayer indicate that this membrane undergoes changes of intermolecular organization mostly ascribed to the protein fraction, above a lateral surface pressure of ca. 20 mNrm. The behavior is consistent with a surface pressure-dependent relocation of protein components in the film. This has marked effects on the stability, molecular packing, and dipolar organization of the myelin interface. q 1998 Elsevier Science B.V.
Journal of Tropical Ecology, 2005
2005). Evidence for direct water absorption by the shoot of the desiccationtolerant plant Vellozi... more 2005). Evidence for direct water absorption by the shoot of the desiccationtolerant plant Vellozia flavicans in the savannas of central Brazil.
Journal of Periodontology, 2006
Background: Implant esthetics have been the focus of attention for the last few years, and one of... more Background: Implant esthetics have been the focus of attention for the last few years, and one of the most important points is the effect that interimplant distances can have on papilla formation and bone loss. The aim of this study was to evaluate the effect that distances of 1, 2, and 3 mm between implants after prosthetic restoration will have on crestal bone resorption (from the top of the implant to the bone crest [TI-BC]) and bone resorption (from the top of the implant to the first bone-to-implant contact TI-BIC) in two-stage implants used in a submerged and non-submerged protocol.
Talanta, 2008
A preconcentration method for manganese determination by sequential injection cloud point extract... more A preconcentration method for manganese determination by sequential injection cloud point extraction with subsequent detection by flame atomic absorption spectrometry (FAAS) has been developed. The enrichment of Mn was performed after a preliminary on-line cloud point extraction and entrapment of manganese-containing surfactant aggregated within a minicolumn packed with cotton. The laboratorymade reagent 4-(5 -bromo-2 -thiazolylazo)orcinol (Br-TAO) and the surfactant Triton X-114 were used for cloud point extraction. The manganese ions were eluted with sulphuric acid solution and directly introduced into the FAAS. Chemical and flow variables affecting the preconcentration were studied. Using a sample volume of 2.80 mL the limit of detection and enrichment factor were calculated to be 0.5 g L −1 and 14, respectively. The sample frequency is 48 h −1 , considering a total run cycle of 75 s. The accuracy of the proposed method has been demonstrated by the analysis of the certified reference biological materials rice flour and tomato leaves. The method has been applied to determination of manganese in food samples.
Oecologia, 2005
About half of the Amazon rainforest is subject to seasonal droughts of 3 months or more. Despite ... more About half of the Amazon rainforest is subject to seasonal droughts of 3 months or more. Despite this drought, several studies have shown that these forests, under a strongly seasonal climate, do not exhibit significant water stress during the dry season. In addition to deep soil water uptake, another contributing explanation for the absence of plant water stress during drought is the process of hydraulic redistribution; the nocturnal transfer of water by roots from moist to dry regions of the soil profile. Here, we present data on patterns of soil moisture and sap flow in roots of three dimorphic-rooted species in the Tapajós Forest, Amazônia, which demonstrate both upward (hydraulic lift) and downward hydraulic redistribution. We measured sap flow in lateral and tap roots of our three study species over a 2-year period using the heat ratio method, a sap-flow technique that allows bi-directional measurement of water flow. On certain nights during the dry season, reverse or acropetal flow (i.e.,in the direction of the soil) in the lateral roots and positive or basipetal sap flow (toward the plant) in the tap roots of Coussarea racemosa (caferana), Manilkara huberi (maçaranduba) and Protium robustum (breu) were observed, a pattern consistent with upward hydraulic redistribution (hydraulic lift). With the onset of heavy rains, this pattern reversed, with continuous night-time acropetal sap flow in the tap root and basipetal sap flow in lateral roots, indicating water movement from wet top soil to dry deeper soils (downward hydraulic redistribution). Both patterns were present in trees within a rainfall exclusion plot (Seca Floresta) and to a more limited extent in the control plot. Although hydraulic redistribution has traditionally been associated with arid or strongly seasonal environments, our findings now suggest that it is important in ameliorating water stress and improving rain infiltration in Amazonian rainforests. This has broad implications for understanding and modeling ecosystem process and forest function in this important biome.
Materials Research-ibero-american Journal of Materials, 2007
In this study HDPE specimens were fabricated by selective laser sintering using different particl... more In this study HDPE specimens were fabricated by selective laser sintering using different particle sizes to obtain controlled variations in the porosity. Electron microscopy, density measurements and mechanical analyses were conducted for the characterization of the specimens. Parts with controlled pore gradients were also manufactured and characterized. The specimens with larger particle sizes had a high sintering degree and a significant level of close pores, as shown by microscopy and density analyses. However, the mechanical properties of specimens prepared with large particles had low values due to the limited density of union points, i.e., low neck number/area. HDPE parts with pore gradients were prepared by selective laser sintering demonstrating that this technique can be used to easily control the structure and the properties of the parts manufactured. This technology may have applications in areas such as drug delivery devices and scaffolds for tissue engineering.
This paper is concerned with video sequence analysis for urban area surveillance applications. Th... more This paper is concerned with video sequence analysis for urban area surveillance applications. The aim is to detect, track and classify targets entering a urban scene under varying illumination conditions and distracters. The paper contributions consist in the integration of algorithms for performing the various tasks and in their statistical evaluation. Results are presented on the basis of a benchmark video sequence.
Journal of Periodontology, 2006
The position of gingival soft tissues depends on the position and health of the underlying alveol... more The position of gingival soft tissues depends on the position and health of the underlying alveolar bone. The aim of this study was to evaluate the influence of different interimplant distances on crestal bone resorption after prosthetic restoration with a 5-mm distance between the contact point and the bone crest. The mandibular bilateral premolars of six dogs were extracted and, after 12 weeks, each dog received eight implants, totaling 48 implants in the experiment. Two pairs, one in each hemiarch, were separated by 2 mm (group 1) and two by 3 mm (group 2). After 12 weeks, the implants received temporary acrylic prostheses. After 4 more weeks, metallic crowns substituted the temporary prostheses. After 4 more weeks, the animals were sacrificed, and their hemimandibles were removed, dissected, and processed. For groups 1 and 2, respectively, the mean of interimplant bone resorption (IIBR) analyzed histologically was 2.03 and 1.98 mm (P >or=0.05), and the mean of the distal extension bone resorption was 2.04 and 1.92 mm for groups 1 and 2, respectively (P >or=0.05). The crestal bone resorption between the implants was 0.13 mm (P >or=0.05) for both groups. The mean of IIBD for groups 1 and 2 was 79% and 80%, respectively. When the IIBD was compared to the distal extension bone density for group 1 (79% and 64%) and group 2 (80% and 62%), statistically significant differences were obtained for both groups (P <or=0.05). The distances of 2 and 3 mm between implants do not result in statistically significant differences in crestal bone resorption around implant surfaces in dogs. The bone density is enhanced when loading is present at…
Journal of Oral Implantology, 2006
Implant esthetics has been the focus of attention for the past decade, and one vital issue is the... more Implant esthetics has been the focus of attention for the past decade, and one vital issue is the effect of interimplant distance on interimplant papilla formation and crestal bone loss. The aim of this study was to evaluate the effect of 1, 2, and 3 mm of interimplant distance on papilla formation and crestal resorption in submerged and nonsubmerged Ankylos implants after prosthetic restoration. Bilateral mandibular premolars of 7 dogs were extracted, and after 12 weeks each dog received 8 implants. Implants were placed so that 3 interimplant distances were created at 1 mm (group 1), 2 mm (group 2), and 3 mm (group 3). The sides and the position of the groups were randomly selected. Twelve weeks after placement, the implants received metallic prostheses that allowed 5 mm of space between the prosthetic contact point (CP) and the crestal bone (CB). After 8 weeks, the distance between the CP and the papilla (CP-P) and the gingival height at the distal proximal aspect of the prosthesis (CP-DE) was clinically measured. Radiographic images were obtained to measure the distance of the CP to the CB within the interimplant surfaces (CP-IP) and adjacent to the edentulous surfaces (CP-ED). The clinical measurement of CP-P for submerged and nonsubmerged implants was 3.57+/-1.17 mm and 3.10+/-0.82 mm for group 1, 3.57+/-0.78 mm and 3.16+/- 0.87 mm for group 2, and 3.35+/- 0.55 mm and 3.07+/-0.93 mm for group 3. The CP-DE was 3.25+/-0.77 mm for submerged and 2.78+/- 0.64 mm for nonsubmerged implants. The CP-IP for the submerged and nonsubmerged implants was 6.91+/-0.95 mm and 7.68+/-2.73 mm for group 1, 7.46+/-1.43 mm and 5.87+/-1.71 mm for group 2, and 7.72+/-0.81 mm and 7.59+/-1.33 mm for group 3. The CP-ED was 6.77+/-1.33 mm for submerged implants and 6.03+/-1.58 mm for nonsubmerged implants. There were no statistical significant differences for any of the measured parameters. We conclude that when the distance from the CP to the CB was 5 mm, interimplant distances of 1 to 3 mm did not affect papilla formation or crestal resorption of submerged or nonsubmerged implants in the dog model.
This paper presents a tool for prototyping ODE (Ordinary Differential Equations) based systems in... more This paper presents a tool for prototyping ODE (Ordinary Differential Equations) based systems in the area of computational modeling. The models, tailored during the project step of the system development, are recorded in MathML, a markup language built upon XML. This design choice improves interoperability with other tools used for mathematical modeling, mainly considering that it is based on Web architecture. The resulting work is a Web portal that transforms an ODE model documented in MathML to a C++ API that offers numerical solutions for that model.
EverQuest and Ultima Online are currently implemented as client-server systems. Although this app... more EverQuest and Ultima Online are currently implemented as client-server systems. Although this approach allows the development of commercially viable MMG services, the costs associated with running a scalable client-server MMG service are often too high for small companies or research projects. This paper proposes FreeMMG, a mixed peer-to-peer and client-server approach to the distribution aspect of MMGs. It is argued that the FreeMMG model supports scalable, cheat-resistant, massively multiplayer realtime strategy (RTS) games using a lightweight server that delegates the bulk of the game simulation to the clients. A working prototype game called FreeMMG Wizards is presented, together with some preliminary scalability test results featuring up to 300 simulated game clients connected to a FreeMMG server. The results show that the measured server traffic can be considered very low if compared with more centralized alternatives.
Proceedings of The National Academy of Sciences, 2005
Hydraulic redistribution (HR), the nocturnal vertical transfer of soil water from moister to drie... more Hydraulic redistribution (HR), the nocturnal vertical transfer of soil water from moister to drier regions in the soil profile by roots, has now been observed in Amazonian trees. We have incorporated HR into an atmospheric general circulation model (the National Center for Atmospheric Research Community Atmospheric Model Version 2) to estimate its impact on climate over the Amazon and other parts of the globe where plants displaying HR occur. Model results show that photosynthesis and evapotranspiration increase significantly in the Amazon during the dry season when plants are allowed to redistribute soil water. Plants draw water up and deposit it into the surface layers, and this water subsidy sustains transpiration at rates that deep roots alone cannot accomplish. The water used for dry season transpiration is from the deep storage layers in the soil, recharged during the previous wet season. We estimate that HR increases dry season (July to November) transpiration by Ϸ40% over the Amazon. Our model also indicates that such an increase in transpiration over the Amazon and other drought-stressed regions affects the seasonal cycles of temperature through changes in latent heat, thereby establishing a direct link between plant root functioning and climate.
Resumo: A gestão logística nos terminais portuários está apoiada basicamente no gerenciamento da ... more Resumo: A gestão logística nos terminais portuários está apoiada basicamente no gerenciamento da informação. Alguns terminais de container no Brasil tem investido altas somas em infra-estrutura de TI de última geração, para poder gerenciar e oferecer serviços de ...
Current Opinion in Colloid & Interface Science, 2004
Advances in understanding how glycosphingolipids and chemically related sphingolipids affect the ... more Advances in understanding how glycosphingolipids and chemically related sphingolipids affect the structure and dynamics of bio-interfaces have been grouped in four inter-related areas: (a) influence of chemical structure in local interactions along lateral and transverse membrane planes; (b) effect of polar head group and hydrocarbon moieties on the mesomorphic state; (c) thermodynamic–geometric compensations affecting interfacial topology; and (d) domain segregation
This paper shows how to use a decision-theoretic task scheduler in order to automatically generat... more This paper shows how to use a decision-theoretic task scheduler in order to automatically generate efficient intention selection functions for BDI agent-oriented programming languages. We concentrate here on the particular extensions to a known BDI language called AgentSpeak(L) and its interpreter which were necessary so that the integration with a task scheduler was possible. The proposed language, called AgentSpeak(XL), has several other features which increase its usability; some of these are indicated briefly in this paper. We assess the extended language and its interpreter by means of a factory plant scenario where there is one mobile robot that is in charge of packing and storing items, besides other administrative and security tasks. This case study and its simulation results show that, in comparison to AgentSpeak(L), AgentSpeak(XL) provides much easier and efficient implementation of applications that require quantitative reasoning, or require specific control over intentions (e.g., for giving priority to certain tasks once they become intended).
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Papers by Rafael Oliveira