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Aspectos morfo-anat?micos da folha de Baccharis dracunculifolia DC. (Asteraceae) visando a identifica??o da origem botanica da própolis
Oliveira, Virginia del Carmen;Bastos, Esther Margarida;
Acta Botanica Brasilica , 1998, DOI: 10.1590/S0102-33061998000400012
Abstract: the leaf anatomy of b. dracunculifolia, in different developmental stages, was studied, with the purpose of characterizing the secretory structures that can be used as indicators for determining of the botanical origin of propolis produced by apis mellifera. the material was collected in the municipal district of jaboticatubas, minas gerais state, where experimental hives were installed. the studied species are characterized by having the surface of the youngest leaves densely covered by glandular and non-glandular trichomes. the glandular trichomes are abundant in the early stages of leaf growth and uncommon in mature leaves. the mature leaf is amphistomatic. the mesophyll consists of palisade cells, scarce spongy parenchyma and secretory ducts associated to the phloem. the leaf fragments, stomata, glandular trichomes and non-glandular trichomes present in propolis samples are similar to those found in b. dracunculifolia leaves.
C- and N-truncated antimicrobial peptides from LFampin 265 - 284: Biophysical versus microbiology results
Ad?o Regina,Nazmi Kamran,Bolscher Jan,Bastos Margarida
Journal of Pharmacy and Bioallied Sciences , 2011,
Abstract: Lactoferrin is a glycoprotein with two globular lobes, each having two domains. Since the discovery of its antimicrobial properties, efforts have been made to find peptides derived from this protein showing antimicrobial properties. Most peptides initially studied were derived from Lactoferricin B, obtained from the protein by digestion with pepsin. More recently, a new family of antimicrobial peptides (AMPs) derived from Lactoferrin was discovered by Bolcher et al, and named Lactoferrampin (LFampin). The original sequence of LFampin contained residues 268 - 284 from the N1 domain of Lactoferrin. From this peptide, the Bolscher′s group synthesized a collection of peptides obtained by extension and / or truncation at the C or N-terminal sides, in order to unravel the main structural features responsible for antimicrobial action. Here, we present results for three of these peptides, namely LFampin 265 - 284, LFampin 265 - 280, and LFampin 270 - 284. The peptides were tested against bacteria (E. coli and S. sanguinis), fungi (C. albicans), and model membranes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dimyristoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (DMPG), and their mixtures at a ratio of 3 : 1 (DMPC : DMPG (3 : 1)). The ability to adopt a helical conformation was followed by a circular dichroism (CD), and the perturbation of the gel to the liquid-crystalline phase transition of the membrane was characterized by differential scanning calorimetry (DSC). Distinct behavior was observed in the three peptides, both from the microbiology and model membrane studies, with the biophysical results showing excellent correlation with the microbiology activity studies. LFampin 265 - 284 was the most active peptide toward the tested microorganisms, and in the biophysical studies it showed the highest ability to form an a-helix and the strongest interaction with model membranes, followed by LFampin 265 - 280. LFampin 270 - 284 was inactive, showing marginal secondary structure and no interaction with the pathogen model membranes.
Electrochemical Behavior of Ni(II)-Salen at the Mercury Electrode
Pércio Augusto Mardini Farias,Margarida Bethlem Rodrigues Bastos
International Journal of Electrochemistry , 2013, DOI: 10.1155/2013/257926
Abstract: The complex Ni(II)-salen has been studied using cyclic and square-wave cathodic stripping voltammetry at the static mercury drop electrode in an aqueous media of phosphate and Hepes buffers (at pH 7.0). The resulting voltammograms consist of a totally irreversible one-electron transfer attributable to the coupling of Ni(II) salen/Ni(I) salen via an EC mechanism. The mean value for the transfer coefficient α in both supporting electrolytes was calculated as 0.35 ± 0.05. The amount of reactant adsorbed after 60?s of accumulation at ?700?mV was calculated to be 2.8 × 10?8?mol·cm?2. The detection limit for nickel determination was found to be 3.4 × 10?9?mol?L?1. 1. Introduction The effective clinical use of cis-diammine dichloro platinum(II) complex and other platinum complexes in the treatment of human cancer has stimulated studies in the interaction of DNA with different metal complexes. While some metal complexes possess potential antitumor activities, many others are persistent environmental hazards. The understanding of the precise nature of the interaction of different metal complexes with DNA is crucial to better predict their utilization for diverse purposes such as pharmacology, controlling genetic information, and the elucidation of protein-DNA contacts or gene therapy [1]. Several areas of chemistry have taken great interest in salen-type Schiff bases and their complexes with transition metals. This is mainly due to their biological activity [2, 3], optical [4, 5], catalytic [6–9], chromophoric [10], thermochromic [11], and photochromic [12] properties. In analytical chemistry, this class of compounds has been used to impregnate ion exchange resins for the study of Cu(II), Co(II), and Ni(II) complexes [13], in the fluorescent analysis of some amines [14] and amino acids [15] and in solvent extraction of Ga(II) and Fe(III) complexes [16]. Ni(II)-selective ion sensors of salen-type Schiff base chelates have also been developed [17]. Recently, it was found that some transition metal complexes, such as manganese [1, 18], nickel [19–23], iron [24], ruthenium [25], and copper [26], with ligands of the salen type can selectively modify DNA and RNA [27–29]. The oxidative and reductive chemistry of nickel(II) complexes with Schiff bases of salen type has been studied extensively in organic solvents with different coordinating strength [30–37]. In the present work, the electrochemical behavior of Ni(II)-salen (Figure 1) at a mercury electrode in an aqueous phosphate and Hepes buffers (pH 7.0) by cyclic and square-wave stripping voltammetry has been
Acta Biológica Colombiana , 2011,
Abstract: propolis is a resinous material produced by bees from various plant sources. the objective of this study was to characterize propolis samples of apis mellifera from the colombian andean region, regarding the antimicrobial and physicochemical profiles. we used the technique of disk diffusion with ethanol extracts of propolis against escherichia coli, staphylococcus aureus and candida albicans. the physicochemical characterization included percentage of solids content, wax, oxidation index and quantitative determination of phenolic and flavonoids compounds. all samples showed antibacterial activity, with inhibition zones between 8,0 and 12,0 mm for e. coli and between 8,3 and 23,5 mm for s. aureus. we did not observe any activity against c. albicans. the physical and chemical parameters cited above showed a variation from 2.72 to 9.17%, 0 to 2%, 3 to 51 s, 0.1 to 0.5 (w/w) and 0.02 to 0.95 (p/p), respectively. the antimicrobial profile observed, related to the physicochemical profile, suggests the need for further studies to determine the geographical and botanical origin of the samples studied.
Comprometimento organizacional: uma análise do conceito expresso por servidores universitários no cotidiano de trabalho
Bastos, Antonio Virgílio B;Brand?o, Margarida G. A;Pinho, Ana Paula M;
Revista de Administra??o Contemporanea , 1997, DOI: 10.1590/S1415-65551997000200006
Abstract: research on organizational commitment is characterized by an excessive fragmentationand pulverization of measurement. it urges the need for a conceptual analysis that allowsthe stablishment, in a more consensual manner, of boundaries of the very concept ofcommitment, by contrasting it with other concepts common to organizational research.therefore, this study has aimed to analyse the concept of commitment itself, as it isexpressed by workers, taking this as a starting point for a revision of the standardinstruments currently available. the research was conducted among workers from fourpublic universities (unb, ufba, ufmg, ufu). its first step was the applyance of anopen questionnaire to 240 workers, followed by a second phase of interviews with asubsample of 40 workers. answers were analysed qualitatively, by creating a system ofcategories for their content. indicators thus devised have allowed the identification of the main foci and basis of the concept of commitment expressed by the participants. results are then confronted with the concepts of commitment currently in use inorganizational research.
Morfológica e Castilhamente: um Estudo das Constru??es X-mente no Português do Brasil
BASILIO, Margarida;
DELTA: Documenta??o de Estudos em Lingüística Teórica e Aplicada , 1998, DOI: 10.1590/S0102-44501998000300003
Abstract: this work addresses the question of the morphological structure of x-mente forms and of the degree of productivity of -mente in forming adverbs in brazilian portuguese. the author (a) shows that -mente is not properly a suffix in brazilian portuguese; (b) claims that, although the great majority of morphological types of adjectives can be involved in x-mente adverbs, the formative -mente does not have inflection level productivity; and (c) presents a preliminary study of productivity conditions of -mente in forming modal adverbs.
Metaphor and metonymy in word formation
Basilio, Margarida;
DELTA: Documenta??o de Estudos em Lingüística Teórica e Aplicada , 2006, DOI: 10.1590/S0102-44502006000300006
Abstract: this work investigates the relevance of analogy, metonymy and metaphor in word formation patterns and their products. initially, the semantic side of proportional analogy in morphological restructuring is analyzed. the work then concentrates on the role of metonymy in the formation of instrumentals and agent nouns. the last part of the work is dedicated to the role of metaphor in compounding. the main point of the paper is to show how metaphor is fundamental to the constitution of the lexicon and, consequently, how unfortunate for the discussion of metaphor in language is the relative disregard to word-formation processes.
Superdota??o: conceitos e modelos de diagnóstico e interven??o psicoeducativa
Pocinho, Margarida;
Revista Brasileira de Educa??o Especial , 2009, DOI: 10.1590/S1413-65382009000100002
Abstract: the definition of giftedness is not exempt from unreliability and controversy. the concept is not static, it is in constant evolution, being that the current trend is characterized by the balance of other variables beyond the cognitive and intelligence. according to the world council for gifted and talented children, one can be considered gifted when exhibiting high performance or potential, in any of the following aspects in isolation or combined: general intellectual capacity, specific academic skill, creative or productive thinking, special talent for the visual, dramatic and musical arts, motor skills and capacity for leadership. thus, the multiplicity of concepts ends up translating into a multiplicity of criteria that must be considered in the definition of giftedness, which means that assessment must also be multifaceted. as a result, a broad range of intervention proposals is required, as well as recourse to different agents, procedures and assessment instruments.
Georgeta CISLARU, Frédéric PUGNIERE-SAAVEDRA, Frédérique, SITRI, (coord). Analyse de discours et demande sociale. (...)
Isabel Margarida
Linguística : Revista de Estudos Linguísticos da Universidade do Porto , 2009,
L1 Educational Studies in Language and Literature , 2009,
Abstract: This article describes the application of a Comprehension Strategies Programme (CSP) designedto improve the reading comprehension of students with learning difficulties. The programme wasimplemented with 102 ninth grade students from Portuguese public schools with low achievement on aparticular subject: Portuguese. An evaluation was done on the effects of the programme on reading comprehensionand on school achievement. The Experimental Group presented significant improvementswhen compared to the Control Group (n=108) on the dimensions considered. This indicates that the CSPcan bring benefits to low achieving students who have Portuguese as a mother tongue.
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