Showing papers by "Universidade Federal de Santa Catarina published in 2003"

The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability

Abstract: Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) widespread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications.

Anti-inflammatory compounds of plant origin. Part I. Action on arachidonic acid pathway, nitric oxide and nuclear factor kappa B (NF-kappaB).

Abstract: Over the last 10 years, a significant body of evidence has emerged indicating that chemically diverse classes of naturally-occurring substances derived from higher plants are of potential interest for therapeutic interventions in several inflammatory diseases. Part I of this review article focuses on our current knowledge of the mechanisms by which a large range of plant-derived constituents interfere with three relevant targets involved in the inflammatory process, namely arachidonic acid metabolite pathways, nitric oxide and NF-kappaB, and discusses their potential therapeutic use in the management of relevant inflammatory diseases.

Prevalence of traumatic dental injury and associated factors among 12-year-old school children in Florianópolis, Brazil.

Abstract: The objective of this study was to assess the prevalence and type of accidents that resulted in traumatic injuries to the permanent dentition of 12-year-old school children in Florianopolis, Brazil. A dental trauma cross-sectional survey was carried out through clinical examination of upper and lower permanent incisors and interviews with 307 12-year-old school children enrolled in public primary schools. Intra-examiner diagnosis variability was good, measured by kappa values on tooth-by-tooth basis. The prevalence of dental injury was 18.9%. There was no statistical difference in the prevalence between boys and girls (P = 0.103). The main types of accidents that resulted in dental injuries were falls and collisions with objects or people. It can be concluded that the prevalence of dental injuries in Florianopolis, Brazil is high and they have a great potential to be considered an emerging public health problem.

Cytotoxicity and potential antiviral evaluation of violacein produced by Chromobacterium violaceum.

Abstract: Natural products are an inexhaustible source of compounds with promising pharmacological activities including antiviral action. Violacein, the major pigment produced by Chromobacterium violaceum, has been shown to have antibiotic, antitumoral and anti-Trypanosoma cruzi activities. The goal of the present work was to evaluate the cytotoxicity of violacein and also its potential antiviral properties.The cytotoxicity of violacein was investigated by three methods: cell morphology evaluation by inverted light microscopy and cell viability tests using the Trypan blue dye exclusion method and the MTT assay. The cytotoxic concentration values which cause destruction in 50% of the monolayer cells (CC 50 ) were different depending on the sensitivity of the method. CC 50 values were ≥ 2.07 ± 0.08 µM for FRhK-4 cells: ≥ 2.23 ± 0.11 µM for Vero cells; ≥ 2.54 ± 0.18 µM for MA104 cells; and ≥ 2.70 ± 0.20 µM for HEp-2 cells. Violacein showed no cytopathic inhibition of the following viruses: herpes simplex virus type 1 (HSV-1) strain 29-R/acyclovir resistant, hepatitis A virus (strains HM175 and HAF-203) and adenovirus type 5 nor did it show any antiviral activity in the MTT assay. However violacein did show a weak inhibition of viral replication: 1.42 ± 0.68%, 14.48 ± 5.06% and 21.47 ± 3.74% for HSV-1 (strain KOS); 5.96 ± 2.51%, 8.75 ± 3.08% and 17.75 ± 5.19% for HSV-1 (strain ATCC/VR-733); 5.13 ± 2.38 %, 8.18 ± 1.11% and 8.51 ± 1.94% for poliovirus type 2; 8.30 ± 4.24%; 13.33 ± 4.66% and 24.27 ± 2.18% for simian rotavirus SA11, at 0.312, 0.625 and 1.250 mM, respectively, when measured by the MTT assay.

Cryopreservation of sperm in Brazilian migratory fish conservation

Abstract: Simple, effective protocols for cryopreserving milt of five Brazilian migratory characids (Brycon orbignyanus, Prochilodus lineatus, Piaractus mesopotamicus, Salminus maxillosus and Leporinus elongatus) and one Brazilian migratory catfish (Pseudoplatystoma corruscans) are described. Milt was frozen and stored in dry shippers immediately after collection, making the procedure practical for use in the field. A diluent of 5% glucose, 10% dimethyl sulphoxide and 10% egg yolk was effective for all of the characid species, and a diluent of 10% methanol and 15% powdered milk was effective for P. corruscans. Milt was thawed in an ambient temperature water bath (28-30° C). Activation of thawed milt was effective with either saline (0.9 or 0.45% NaCl) or bicarbonate (1% NaHCO 3 ). Fertilization rates with frozen milt varied between 49 and 300% of the control. Application of the technology for increasing genetic diversity in hatchery programmes for enhancement, mitigation or conservation breeding is discussed, as is its application in aquaculture. Inappropriate use of the technology can threaten wild biodiversity and appropriate legislation and education may be required for its responsible use.

Blockade of nociceptin/orphanin FQ-NOP receptor signalling produces antidepressant-like effects: pharmacological and genetic evidences from the mouse forced swimming test.

Abstract: Nociceptin/orphanin FQ (N/OFQ), the endogenous ligand of the NOP receptor, regulates several central functions such as pain transmission, learning and memory, fear and anxiety and feeding and locomotor activity. It has been recently reported that NOP receptor antagonists induce antidepressant-like effects in the mouse forced swimming test (FST), i.e. reduce immobility time. This assay was used in the present study for further investigating the involvement of the NOP receptor in depression states. In male Swiss mice, intracerebroventricular injection (i.c.v) of the novel NOP receptor antagonist, UFP-101 (1-10 nmol) dose-dependently reduced the immobility time (control 192 +/- 14 s, UFP-101 91 +/- 15 s). The effect of 3 or 10 nmol UFP-101 was fully or partially reversed, respectively, by the coadministration of 1 nmol N/OFQ, which was inactive per se. NOP receptor knockout mice showed a reduced immobility time compared with their wild-type littermates (wild-type 215 +/- 10 s, knockout 143 +/- 12 s). Moreover, i.c.v. injected UFP-101 (10 nmol) significantly reduced immobility time in wild-type mice but not in NOP receptor knockout animals. In conclusion, these results, obtained using a combined pharmacological and genetic approach, indicate that blockade of the N/OFQ-NOP receptor signalling in the brain produces antidepressant-like effects in the mouse FST. These findings support the NOP receptor as a candidate target for the development of innovative antidepressant drugs.

A new look at the crossed-product of a C^*-algebra by an endomorphism

Abstract: We give a new definition for the crossed-product of a C*-algebra A by a *-endomorphism arises as the result of our construction when applied to the corresponding Markov subshift and a very natural transfer operator.

Review Article: recent advances in metal-ceramic brazing

Abstract: Metal-ceramic joining has slowly but steadily become an important manufacturing step. The evolution of joining processes has allowed ceramics to be used in combination with metals in a number of hybrid devices from traditional light bulbs and seals to improved cutting tools and modern monitoring and measuring electronic devices. New joining methods and newer approaches to conventional methods have been developed aiming at joints characterized by improved reliability, and interfaces capable of withstanding high-temperature resistance with minimum residual stresses. A summary of recent improvements on alternative approaches to ceramic-metal joining as well as new developments on brazing are presented herein. The present review also focuses on recent advances towards brazing metallized ceramics and the selection of filler alloys, since in a scenario that includes joining by laser and direct bonding with liquid transient phases, brazing continues to be by far the most widely used approach to joining as a result of its low-cost and possibility to join intricate geometries for large-scale production. Finally, methods to evaluate the mechanical strength and residual thermal stresses are presented in addition to alternative approaches to minimize residual stresses and, consequently, improve joint reliability.

Trypanocidal and Leishmanicidal Properties of Substitution-Containing Chalcones

Abstract: Ten chalcones were synthesized and tested as potential leishmanicidal and trypanocidal agents. All tested compounds caused concentration-dependent inhibition of the in vitro growth of Leishmania braziliensis and Trypanosoma cruzi with no significant toxic effect towards host macrophages. Our results show that the positions of the substituents seem to be critical for their antiprotozoal activities.

A Globally Convergent Filter Method for Nonlinear Programming

Abstract: In this paper we present a filter algorithm for nonlinear programming and prove its global convergence to stationary points. Each iteration is composed of a feasibility phase, which reduces a measure of infeasibility, and an optimality phase, which reduces the objective function in a tangential approximation of the feasible set. These two phases are totally independent, and the only coupling between them is provided by the filter. The method is independent of the internal algorithms used in each iteration, as long as these algorithms satisfy reasonable assumptions on their efficiency. Under standard hypotheses, we show two results: for a filter with minimum size, the algorithm generates a stationary accumulation point; for a slightly larger filter, all accumulation points are stationary.

Cloud-point extraction for the determination of Cd, Pb and Pd in blood by electrothermal atomic absorption spectrometry, using Ir or Ru as permanent modifiers

Abstract: The phase-separation phenomenon of nonionic surfactants occurring in aqueous solution was used to perform the extraction of Cd, Pb and Pd from digested blood samples. After complexation with O,O-diethyldithiophosphate (DDTP) in hydrochloric acid medium, the analytes are quantitatively extracted to the phase rich in the nonionic surfactant octylphenoxypolyethoxyethanol (Triton X-114) after centrifugation. 0.1 mol L−1 HNO3 in methanol was added to the surfactant-rich phase prior to its analysis by electrothermal atomic absorption spectrometry (ETAAS). The adopted concentrations for DDTP, Triton X-114 and hydrochloric acid were all optimized, and the performance of 500 µg of either iridium or ruthenium as a permanent modifier was evaluated for the determination of Cd and Pb. No modifier was required for the Pd determinations. Detection limits (3σB) of 0.02 µg L−1, 0.08 µg L−1 and 0.014 µg L−1, along with enrichment factors of 71, 34 and 100 for Cd, Pb and Pd, respectively, were achieved. The proposed procedure was applied to the analysis of two certified blood reference samples (lyophilized bovine blood and reconstituted human blood) after microwave-assisted digestion in a mixture of H2O2 and HNO3. Comparison with certified values and recovery tests were performed to validate the methodology; good accuracy was obtained within the 95% confidence interval in both cases.

Phosphate diester hydrolysis and DNA damage promoted by new cis-aqua/hydroxy copper(II) complexes containing tridentate imidazole-rich ligands.

Abstract: The tridentate Schiff base [(2-(imidazol-4-yl)ethyl)(1-methylimidazol-2-yl)methyl)imine (HISMIMI) and its reduced form HISMIMA were synthesized and characterized, as well their mononuclear cis-dihalo copper(II) complexes 1 and 2, respectively. In addition, the dinuclear [CuII(μ-OH)2CuII]2+ complexes (3) and (4) obtained from complexes 1 and 2, respectively, were also isolated and characterized by several physicochemical techniques, including magnetochemistry, electrochemistry, and EPR and UV−vis spectroscopies. The crystal structures of 1 and 2 were determined by X-ray crystallography and revealed two neutral complexes with their tridentate chelate ligands meridionally coordinated. Completing the coordination spheres of the square-pyramidal structures, a chloride ion occupies the apical position and another is bonded in the basal plane. In addition, complexes 1 and 2 were investigated by infrared, electronic, and EPR spectroscopies, cyclic voltammetry, and potentiometric equilibrium studies. The hydrolyti...

Microstructural investigation of a silica fume–cement–lime mortar

Abstract: Several additions, minerals and organic, are used in mortars, such as pozzolanic materials, cementicious materials and polymers. Literature about the use of additions in masonry mortars (cement/lime/sand mixes) is scarce; usually, studies are about concrete mortars. The purpose of this work is to study the microstructural effects of the substitution of 10% of Portland cement by silica fume in a 1:1:6 (cement/lime/sand mix proportion by volume) masonry mortar. Scanning electron microscopy with energy dispersive X-rays analysis (SEM/EDX) shows that, with silica fume, the C–S–H formed is type III at early ages and that type III and type I coexist at later ages. Silica fume lowers the total porosity and increases compressive strength only at later age and, as expected, the pore structure of mortar with silica fume is found to be finer than of non-silica fume mortar.

Reflexões metodológicas para o estudo das práticas alimentares

Abstract: A alimentacao humana, envolvendo aspectos psicologicos, fisiologicos e socioculturais, e um fenomeno de grande complexidade e, em assim sendo, o estudo das praticas alimentares tem suscitado o desenvolvimento de instrumentos e metodos no interior de varias disciplinas. Neste artigo, que apresenta a alimentacao humana sob abordagem da Sociologia e da Antropologia, definem-se as diferentes dimensoes do espaco social alimentar, desde o registro do consumo alimentar ate os processos de diferenciacao social envolvendo as formas de cozinhar, as formas de consumir e a temporalidade. Analisam-se os diferentes tipos de dados que podem ser utilizados, tomando-se o cuidado de distinguir os dados comportamentais (que podem ser obtidos tanto pela observacao quanto pela declaracao) dos dados de representacao. Apresentam-se, em seguida, os diferentes instrumentos de coleta e as vias de entrada no fenomeno alimentar. Esses instrumentos metodologicos, construidos no interior de um quadro teorico-sociologico, sao propostos aos pesquisadores da area, objetivando a construcao de uma possivel visao comum, que proporcione uma abordagem pluridisciplinar do fato alimentar.

Fumonisin contamination and fusarium incidence in corn from Santa Catarina, Brazil.

Abstract: In Brazil, the southern region has the highest incidence of esophageal cancer and also the highest production and consumption of corn (Zea mays) products. Corn samples intended for human consumption from the western, northern, and southern regions of the state of Santa Catarina, southern Brazil, had mean total fumonisin B (B(1), B(2), and B(3)) levels of 3.2, 3.4, and 1.7 mg/kg, respectively. Fusarium verticillioides, the predominant fungus in the corn samples, had mean incidences (percent of kernels infected) of 14, 11, and 18% for the three regions, respectively. Additional corn samples intended for animal feed from the southern region had a mean total fumonisin level of 1.5 mg/kg and a mean F. verticillioides incidence of 10%. The fumonisin levels in corn from the state of Santa Catarina, Brazil, were similar to the high levels determined in other high esophageal cancer incidence regions of the world.

Partial Dynamical Systems and the KMS Condition

Abstract: Given a countably infinite 0–1 matrix A without identically zero rows, let 𝒪 A be the Cuntz–Krieger algebra recently introduced by the authors and 𝒯 A be the Toeplitz extension of 𝒪 A , once the latter is seen as a Cuntz–Pimsner algebra, as recently shown by Szymanski. We study the KMS equilibrium states of C * -dynamical systems based on 𝒪 A and 𝒯 A , with dynamics satisfying for the canonical generating partial isometries s x and arbitrary real numbers N x > 1. The KMSβ states on both 𝒪 A and 𝒯 A are completely characterized for certain values of the inverse temperature β, according to the position of β relative to three critical values, defined to be the abscissa of convergence of certain Dirichlet series associated to A and the N(x). Our results for 𝒪 A are derived from those for 𝒯 A by virtue of the former being a covariant quotient of the latter. When the matrix A is finite, these results give theorems of Olesen and Pedersen for 𝒪 n and of Enomoto, Fujii and Watatani for 𝒪 A as particular cases.

Distributed Learning Agents in Urban Traffic Control

Abstract: Automatic learning techniques stand as promising tools to respond to the need of higher efficiency of traffic network, even more so at times of mounting pressure from economic and energy markets. To this end, this paper looks into the operation of a traffic network with distributed, intelligent agents. In particular, it casts the task of operating a traffic network as a distributed, stochastic game in which the agents solve reinforcement-learning problems. Results from computational experiments show that these agents can yield substantial gains with respect to the performance achieved by two other control policies for traffic lights. The paper ends with an outline of future research to deploy machine-learning technology in real-world traffic networks.

Genetic selection of two new rat lines displaying different levels of anxiety-related behaviors.

Abstract: We have recently identified, using two inbred rat strains (Lewis and SHR), the first two loci for an emotionality-related behavior in rats (locomotion in the central area of the open field test). Aiming to develop an alternative genetic model that will help to corroborate the existence of these loci and that could serve as a tool in the study of anxiety, we have started breeding two new rat lines. From a highly heterogeneous population, we have selectively bred rats for four generations with high and low scores for central locomotion in the open field. At the fourth generation, the new outbred lines differed from each other for the selected trait by as much as threefold. At each generation, all rats were also tested in the elevated plus maze and the black and white box, with the two lines differing significantly also in these two models of anxiety. These results suggest that behavioral measures from different tests of emotionality/anxiety are, at least in part, genetically related. They also indicate that this newly developed genetic model (herein named Floripa H and L rat lines) may be useful in the study of anxiety, as well as serving as a tool to test the existence/significance of the two aforementioned loci putatively associated with emotionality.

The association between socioeconomic development at the town level and the distribution of dental caries in Brazilian children

Abstract: OBJECTIVE: To investigate the association between dental caries among children in the state of Sao Paulo, Brazil, and town-level indices of socioeconomic development. METHODS: We examined 15 385 oral-examination records from children aged 5 or 6 years old from 129 towns and cities in the state of Sao Paulo. We studied two outcomes: (1) the mean number of decayed, missing, and filled deciduous teeth (dmft index) and (2) the care index, which is the proportion of decayed teeth that have already been filled. The explanatory variables were the child development index, human development index, illiteracy rate among subjects older than 20 years, household income, Gini coefficient, insufficient income, fluoridated water supply, number of dentists per 10 000 inhabitants, number of dentists in the public service per 10 000 inhabitants, and number of weekly hours of dentist work in the public service per 10 000 inhabitants. Multiple linear regression models were fitted to the two outcome variables (dmft index and care index). RESULTS: The multiple linear regression analysis showed that a higher dmft index was associated with a low child development index, a high illiteracy rate, and an unfluoridated water supply. The child development index was significantly associated with the care index, and the number of dentists in the public service per 10 000 inhabitants showed borderline statistical significance. CONCLUSIONS: Our results indicate that town-level indices of socioeconomic status are significantly correlated with caries indices. Our results also emphasize the beneficial effect that fluoridating water has on reducing the prevalence of dental caries and the fact that strategies for treating and preventing oral diseases should be emphasized within the context of overall health promotion for children.