Showing papers by "Universidade Federal de Santa Catarina published in 2005"

Semi‐empirical analysis of Sloan Digital Sky Survey galaxies – I. Spectral synthesis method

Abstract: The study of stellar populations in galaxies is entering a new era with the availability of large and high-quality data bases of both observed galactic spectra and state-of-the-art evolutionary synthesis models. In this paper we investigate the power of spectral synthesis as a means to estimate the physical properties of galaxies. Spectral synthesis is nothing more than the decomposition of an observed spectrum in terms of a superposition of a base of simple stellar populations of various ages and metallicities, producing as output the star formation and chemical histories of a galaxy, its extinction and velocity dispersion. Our implementation of this method uses the recent models of Bruzual & Charlot and observed spectra in the 3650–8000 A range. The reliability of this approach is studied by three different means: (1) simulations, (2) comparison with previous work based on a different technique, and (3) analysis of the consistency of results obtained for a sample of galaxies from the Sloan Digital Sky Survey (SDSS). We find that spectral synthesis provides reliable physical parameters as long as one does not attempt a very detailed description of the star formation and chemical histories. Robust and physically interesting parameters are obtained by combining the (individually uncertain) strengths of each simple stellar population in the base. In particular, we show that, besides providing excellent fits to observed galaxy spectra, this method is able to recover useful information on the distributions of stellar ages and, more importantly, stellar metallicities. Stellar masses, velocity dispersion and extinction are also found to be accurately retrieved for realistic signal-to-noise ratios. We apply this synthesis method to a volume-limited sample of 50 362 galaxies from the SDSS Data Release 2, producing a catalogue of stellar population properties. Emission lines are also studied, their measurement being performed after subtracting the computed starlight spectrum from the observed one. A comparison with recent estimates of both observed and physical properties of these galaxies obtained by other groups shows good qualitative and quantitative agreement, despite substantial differences in the methods of analysis. The confidence in the present method is further strengthened by several empirical and astrophysically reasonable correlations between synthesis results and independent quantities. For instance, we report the existence of strong correlations between stellar and nebular metallicities, stellar and nebular extinctions, mean stellar age and equivalent width of Hα and 4000-A break, and between stellar mass and velocity dispersion.

Aplicación de diversos métodos químicos para determinar actividad antioxidante en pulpa de frutos

Abstract: El Brazil es considerado un de los principales paises productores de zumos de frutos, ocupando en concreto la tercera posicion respecto a esto. La diversidad de frutos en el mercado es cada vez mayor, introduciendose diariamente nuevos frutos tropicales cuyas propiedades y actividades no estan aun totalmente determinadas. El gobierno brasileno apoya el comercio exterior de frutos, invirtiendo fondos en exposiciones que promueven y situan a los nuevos productos en los paises de la Union Europea, tal como la "Brazilian Fruit Festival" que promociona frutos in natura, pulpas congeladas y zumos procesados. Se publican cada vez en mayor numero nuevas investigaciones que asocian el consumo de frutas con efectos beneficiosos para la salud humana. Este trabajo tiene por objeto la determinacion del indice de fenoles totales (FT), antocianos totales (AT) y la capacidad antioxidante de las pulpas de frutos comerciales congelados, aplicando los metodos espectrofotometrico quimicos mas en boga para la determinacion de la actividad antioxidante (ABTS, DPPH y DMPD). Se ha determinado la capacidad antioxidante de las pulpas de los frutos tropicales de mayor consumo en el mercado del sur de Brazil (mora, uva, acai, guayaba, fresa, acerola, pina, mango, graviola, cupuacu y maracuya) aplicando el metodo ABTS con medidas a dos tiempos (1 y 7 minutos), DPPH (30 y 60 minutos) y DMPD (10 minutos). Los valores TEAC (capacidad antioxidante equivalente al Trolox) obtenidos de las pulpas oscilan entre minimos y maximos de 2,0 y 67,2 µmol/g aplicando el ensayo ABTS, 1,02 y 67,0 µmol/g aplicando DPPH y 4,2 y 46,6 µmol/g aplicando DMPD. La capacidad antioxidante obtenida por los metodos ABTS y DPPH se encuentra correlacionada con el contenido de compuestos fenolicos y antocianos.

Swine and Poultry Pathogens: the Complete Genome Sequences of Two Strains of Mycoplasma hyopneumoniae and a Strain of Mycoplasma synoviae

Abstract: This work reports the results of analyses of three complete mycoplasma genomes, a pathogenic (7448) and a nonpathogenic (J) strain of the swine pathogen Mycoplasma hyopneumoniae and a strain of the avian pathogen Mycoplasma synoviae; the genome sizes of the three strains were 920,079 bp, 897,405 bp, and 799,476 bp, respectively. These genomes were compared with other sequenced mycoplasma genomes reported in the literature to examine several aspects of mycoplasma evolution. Strain-specific regions, including integrative and conjugal elements, and genome rearrangements and alterations in adhesin sequences were observed in the M. hyopneumoniae strains, and all of these were potentially related to pathogenicity. Genomic comparisons revealed that reduction in genome size implied loss of redundant metabolic pathways, with maintenance of alternative routes in different species. Horizontal gene transfer was consistently observed between M. synoviae and Mycoplasma gallisepticum. Our analyses indicated a likely transfer event of hemagglutinin-coding DNA sequences from M. gallisepticum to M. synoviae.

The effect of application time of EDTA and NaOCl on intracanal smear layer removal: an SEM analysis.

Abstract: Teixeira CS, Felippe MCS, Felippe WT. The effect of application time of EDTA and NaOCl on intracanal smear layer removal: an SEM analysis. International Endodontic Journal, 38, 285–290, 2005. Aim To verify, under the scanning electron microscope (SEM), the influence of irrigation time with ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) on intracanal smear layer removal. Methodology Twenty-one extracted human permanent teeth with single straight root canals were included. The root canals of the teeth were instrumented and, at the end of preparation, were irrigated with 3 mL of 15% EDTA, followed by 3 mL of 1% NaOCl for 1 min (group 1), for 3 min (group 2), and for 5 min (group 3). The canals of teeth in group 4 (control) did not receive the final irrigation. The teeth were sectioned longitudinally and prepared for an SEM. The dentinal wall of cervical, middle and apical thirds was graded according to the amount of debris and smear layer remaining on the walls. The results were analysed using the Kruskal–Wallis and Conover–Inman tests. Results In all the canals of experimental groups irrigation with EDTA and NaOCl completely removed the smear layer from the cervical and middle thirds. In the apical third, the dentine surface were partially covered, particularly in the teeth of group 1, where there was significantly more smear layer when compared with the other thirds in the same group (P 0.05). Conclusion In this limited laboratory study, canal irrigation with EDTA and NaOCl for 1, 3 and 5 min were equally effective in removing the smear layer from the canal walls of straight roots.

Social and biological early life influences on severity of dental caries in children aged 6 years.

Abstract: Objective: To investigate the relationship between social and biological conditions experienced in very early life and dental caries in children aged 6 years. Methosd: The design was a dental caries cross-sectional study nested in a birth cohort study started in Pelotas, Brazil, in 1993. The cross-sectional study was carried out in 1999. A random sample of 400 6-year-old children was selected from among 5249 live births in 1993. The World Health Organization (1997) criteria were used to diagnose dental caries. Results from the oral health study were linked to the data concerning perinatal and childhood health and illnesses and family social conditions collected at birth, 1, 3, 6 and 12 months, and in the sixth year of life. Dental caries was the outcome measured at two levels of severity (very low: dmft less than or equal to 1; high: dmft greater than or equal to 4). Unconditional univariate and multiple logistic regression analysis were performed. Results: Self-employed and employees/unemployed, fathers with <8 years of education at time child was born, child's height deficit for age at 12 months; child who did not attend day care centre in sixth year of life; brushing teeth less than once a day, and children with sweet consumption of at least once a day at 6 years were risk factors for high dental caries after controlling for possible confounders. Conclusions: Harmful social and biological risk factors accumulated in early life contributed to the development of a high level of dental caries in childhood.

Gênero Baccharis (Asteraceae): aspectos químicos, econômicos e biológicos

Abstract: The Baccharis genus is represented by more than 500 species distributed mainly in the tropical areas of South America. Many of them are extensively used in folk medicine in the treatment or prevention of anemias, inflammations, diabetes and stomach, liver and prostate diseases. Phytochemical and biological investigations in about 120 species resulted mainly in the isolation of clerodane and labdane diterpenes and flavonoid aglicones with the flavone unit being the most frequent.

Influence of thermal fluctuations on interfacial electron transfer in functionalized TiO2 semiconductors.

Abstract: The influence of thermal fluctuations on the dynamics of interfacial electron transfer in sensitized TiO2-anatase semiconductors is investigated by combining ab initio DFT molecular dynamics simula...

Antibacterial Activity of Coumarins

Abstract: The antibacterial activity of coumarin per se and other 45 coumarin derivatives was tested against strains of Bacillus cereus MIP 96016, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Staphylococcus aureus ATCC 25923. The inhibitory effects of coumarins were affected by their substitution patterns. Osthenol (44) showed the most effective antibacterial activity against Gram-positive bacteria with MIC values ranging between 125 and 62.5 microg/ml. These results suggested that the prenyl chain of 44 at position 8 and the presence of OH at position 7 of the benzenic ring are required for the antibacterial activity against these strains.

High-Resolution Continuum Source AAS: The Better Way to Do Atomic Absorption Spectrometry

Abstract: High-resolution continuum source atomic absorption spectrometry (HR-CS AAS) is the most revolutionary innovation since the introduction of AAS in 1955. Here, the authors provide the first complete and comprehensive discussion of HR-CS AAS and its application to the analysis of a variety of difficult matrices. Published just in time with the first commercial instrument available for this new technique, the book is a must for all those who want to know more about HR-CS AAS, and in particular for all future users.

Antinociceptive Properties of Mixture of α-Amyrin and β-Amyrin Triterpenes: Evidence for Participation of Protein Kinase C and Protein Kinase A Pathways

Abstract: The mixture of the two pentacyclic triterpenes alpha-amyrin and beta-amyrin, isolated from the resin of Protium kleinii and given by intraperitoneal (i.p.) or oral (p.o.) routes, caused dose-related and significant antinociception against the visceral pain in mice produced by i.p. injection of acetic acid. Moreover, i.p., p.o., intracerebroventricular (i.c.v.), or intrathecal (i.t.) administration of alpha,beta-amyrin inhibited both neurogenic and inflammatory phases of the overt nociception caused by intraplantar (i.pl.) injection of formalin. Likewise, alpha,beta-amyrin given by i.p., p.o., i.t., or i.c.v. routes inhibits the neurogenic nociception induced by capsaicin. Moreover, i.p. treatment with alpha,beta-amyrin was able to reduce the nociception produced by 8-bromo-cAMP (8-Br-cAMP) and by 12-O-tetradecanoylphorbol-13-acetate (TPA) or the hyperalgesia caused by glutamate. On the other hand, in contrast to morphine, alpha,beta-amyrin failed to cause analgesia in thermal models of pain. The antinociception caused by the mixture of compounds seems to involve mechanisms independent of opioid, alpha-adrenergic, serotoninergic, and nitrergic system mediation, since it was not affected by naloxone, prazosin, yohimbine, DL-p-chlorophenylalanine methyl ester, or L-arginine. Interestingly, the i.p. administration of alpha,beta-amyrin reduced the mechanical hyperalgesia produced by i.pl. injection of carrageenan, capsaicin, bradykinin, substance P, prostaglandin E2, 8-Br-cAMP, and TPA in rats. However, the mixture of compounds failed to alter the binding sites of [3H]bradykinin, [3H]resiniferatoxin, or [3H]glutamate in vitro. It is concluded that the mixture of triterpene alpha-amyrin and beta-amyrin produced consistent peripheral, spinal, and supraspinal antinociception in rodents, especially when assessed in inflammatory models of pain. The mechanisms involved in their action are not completely understood but seem to involve the inhibition of protein kinase A- and protein kinase C-sensitive pathways.

Caffeine improves spatial learning deficits in an animal model of attention deficit hyperactivity disorder (ADHD) – the spontaneously hypertensive rat (SHR)

Abstract: The spontaneously hypertensive rat (SHR) is generally considered to be a suitable genetic model for the study of attention deficit hyperactivity disorder (ADHD), since it displays hyperactivity, impulsivity, poorly sustained attention, and deficits in learning and memory processes. Converging evidence suggests a primary role of disturbance in the dopaminergic neurotransmission in ADHD patients and in SHR, and in addition, some studies have also demonstrated alterations in adenosinergic neurotransmission in SHR. In the present study, adult female Wistar (WIS) and SHR rats received caffeine (1-10 mg/kg i.p.) 30 min before training, immediately after training, or 30 min before a test session in the spatial version of the Morris water maze. The effect of caffeine administration on WIS and SHR blood pressure was also measured. SHR needed significantly more trials in the training session to acquire the spatial information, but they displayed a similar profile to that of WIS rats in the test session (48 h later), demonstrating a selective deficit in spatial learning. Pre-training administration of caffeine (1-10 mg/kg i.p.) improved this spatial learning deficit in SHR, but did not alter the WIS performance. In contrast, post-training administration of caffeine (3 mg/kg i.p.) did not alter the SHR test performance, but increased memory retention in WIS rats. No dose of caffeine tested altered the mean blood pressure of WIS or SHR. These results demonstrate a selective spatial learning deficit in SHR which can be attenuated by pre-training administration of caffeine. In addition, the present findings indicate that the spatial learning deficit in SHR is not directly related to hypertension.

Experimental data and modeling the supercritical fluid extraction of marigold (Calendula officinalis) oleoresin

Abstract: The fixed bed extraction of marigold ( Calendula officinalis ) oleoresin with liquid and supercritical carbon dioxide was investigated. The operating conditions studied were: pressures ranging from 12 to 20 MPa and temperatures from 293 to 313 K, indicating solvent densities ranging from 666 to 938 k g C O 2 / m 3 , and solvent flow rate varying from 1.3 × 10 −5 to 5.0 × 10 −5 k g C O 2 / s . The results show an increase in the extraction rate, observed through the overall extraction curves (OEC), with increasing pressure. The experimental data were correlated using three models based on differential mass balance equations: (1) the Sovova model; (2) the logistic model presented by Martinez et al. and (3) the desorption model proposed by Tan and Liou; and two models based on heat transfer analogy: (4) the simple single plate model (SSP), presented by Gaspar et al. and (5) the diffusion model, proposed by Crank and presented by Reverchon. All models fitted well the experimental data and the lowest deviation between experimental and correlated data was obtained with the logistic model, for all the experimental conditions evaluated.

[Serum lipids in school kids and adolescents from Florianópolis, SC, Brazil--Healthy Floripa 2040 study].

Abstract: OBJETIVO: Determinar a distribuicao dos lipideos sericos em criancas e adolescentes de Florianopolis, SC. Determinar a associacao entre colesterol nao-desejavel (>170 mg/dL) e outros fatores de risco para aterosclerose. METODOS: Amostra aleatoria estratificada (por idade e tipo de escola) de alunos da rede escolar de Florianopolis. Dados sobre fatores de risco, antropometria, pressao arterial e concentracao serica de lipides foram coletados. RESULTADOS: Participaram 1.053 individuos com idade entre 7 e 18 anos. A concentracao serica do colesterol (media±DP) foi 162±28 mg/dL; dos triglicerideos 93±47 mg/dL; do HDL-colesterol 53±10 mg/dL; do LDL-colesterol 92±24 mg/dL e do colesterol nao-HDL 109± 26 mg/dL. As medias das relacoes CT/HDL e LDL/HDL foram, respectivamente, 3,1±0,6 e 1,8±0,5. Os lipides foram mais elevados nas criancas de escola privada, nos menores de 10 anos, no sexo feminino e nos de cor negra. O modelo de regressao logistica que melhor previu os niveis de colesterol anormal incluia: obesidade, historia familiar de acidente vascular cerebral ou infarto do miocardio, sexo feminino, idade inferior a 10 anos e a imagem corporal definida pelo medico como sobrepeso/obesidade. CONCLUSAO: As concentracoes de lipideos em criancas e adolescentes mostraram valores intermediarios quando comparados a estudos semelhantes. Uma grande parcela dos individuos apresenta niveis de colesterol serico classificados como nao-desejaveis para idade. Pela significância da associacao do colesterol com o excesso de peso, o controle deste fator na infância deve ser tomado como prioridade nos programas de prevencao primordial com o objetivo de reduzir a incidencia das doencas relacionadas a aterosclerose na idade adulta.