999 resultados para Kekkonen, Helena: Rauhan siltaa rakentamassa


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Nitrocompounds are bioactive molecules used as antibacterial, antiparasitic and antitumoral agents. In the past of years, these molecules have been broadly studied in several fields, such as medicinal chemistry, organic chemistry, biochemical, toxicology and electrochemistry. The nitrocompounds mode of action involves the biotransformation of the nitro group, releasing intermediates in the redox process. Some of those intermediates attack enzymes, membranes and DNA, providing the basis for their biological activity and adverse effects. In this report, some aspects regarding the biological activity, mechanism of action and toxicity of nitrocompounds are explored, purposing the research of new bioactive derivatives having low toxicity.

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The natural occurrence, biological activities and synthetic approaches to natural eight-, nine-, and eleven-membered lactones is reviewed. These medium ring lactones are grouped according to ring size, and their syntheses are discussed. The structures of some natural products early identified as medium-ring lactones were revised after total synthesis.

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The bioreduction of a series of substituted a-tetralones, carried out using Daucus carota root (carrot), afforded the corresponding homochiral a-tetralols in variable conversions (9 to 90%) and excellent enantiomeric excesses. Two of the assayed a-tetralones were resistant to the bioreduction conditions. The absolute configurations of four a-tetralols were assigned as being (S), by comparison to the (S)-enantiomers obtained by kinetic resolution promoted by CALB-catalysed acetylation. Additionally, the new 5-methoxy-6-methyl-1-tetralone was synthesized in seven steps from 3-methylsalicylic acid.

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The reaction of ten cis-octalins and cis-octalones with thallium trinitrate (TTN) leads to different products, depending mainly on the substitution pattern of the substrate. Functionalized cis-hydrindanes were obtained from the reaction of 1,2,3,4,4a,5,8,8a-octahydro-4a-methylnaphthalene and of 1,2,3,4,4a,5,8,8a-octahydro-4a,7-dimethylnaphthalene with TTN in acetonitrile, whereas a cyclic ether was formed treating 1,2,3,4,4a,5,8,8a-octahydro-6,8a-dimethylnaphthalen-1-ol with TTN in trimethylorthoformate (TMOF).

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Rock art paintings from Abrigo do Janelão (Minas Gerais, Brazil) were non-destructively investigated by Raman Microscopy, aiming at the identification of materials used, their interaction and degradation. This technique is particularly tailored for heterogeneous samples and allows unequivocal identification of the substances present in the investigated sample. Pigments, were identified together with products of microbiological degradation; no binders were detected. White pigment was identified as calcite (CaCO3), whereas charcoal was used as black, goethite (α-FeOOH) as yellow and hematite (α-Fe2O3) as red. Whewellite (CaC2O4.H2O) and weddelite (CaC2O4.2H2O) were detected and their origin was assigned to degradation products from microbiological activity.

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OBJECTIVE: To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated. MATERIAL AND METHODS: A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled) and three brands of silver nitrate salt (Merck, Synth or Cennabras) at 0, 1, 2, 24, 48, 72, 96 and 168 h after preparation, and storage in transparent or dark bottles. Ionic silver was assayed according to the post-preparation times (2, 24, 48, 72, 96, 168 h) and concentrations (1, 5, 25, 50%) of solutions by atomic emission spectrometry. For each sample of each condition, three readings were obtained for calculating the mean value. Class V cavities were prepared with enamel margins on primary and permanent teeth and restored with the adhesive systems OptiBond FL or OptiBond SOLO Plus SE and the composite resin Filtek Z-250. After nail polish coverage, the permanent teeth were immersed in 25% or 50% AgNO3 solution and the primary teeth in 5% or 50% AgNO3 solutions for microleakage evaluation. ANOVA and the Tukey's test were used for data analyses (α=5%). RESULTS: The mean pH of the solutions ranged from neutral to alkaline (7.9±2.2 to 11.8±0.9). Mean ionic silver content differed depending on the concentration of the solution (4.75±0.5 to 293±15.3 ppm). In the microleakage test, significant difference was only observed for the adhesive system factor (p=0.000). CONCLUSIONS: Under the tested experimental conditions and based on the obtained results, it may be concluded that the aqueous AgNO3 solutions: have neutral/alkaline pH and service life of up to 168 h; the level of ionic silver is proportional to the concentration of the solution; even at 5% concentration, the solutions were capable of indicating loss of marginal seal in the composite restorations; the 3-step conventional adhesive system had better performance regarding microleakage in enamel on primary and permanent teeth.

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Extending from latitude 34ºS to 22ºS the Southern Brazilian shelf constitutes the only part of the Brazilian shelf with a subtropical to temperate environment. The studies on the different geological aspects of the area began in the 1960's and have recently been reassessed after studies related to the determination of the Economic Exclusive Zone. In terms of morphology, the Southern Brazilian shelf may be divided into three sectors, the São Paulo Bight, the Florianópolis-Mostardas Sector and the Rio Grande Cone, characterized by conspicuous differences in terms of geological determining factors, bathymetry, declivities and the presence of canyons and channels. Despite the existence of hundreds of radiocarbon datings the sea level changes curve of southern Brazil during the Last Glacial Cycle is still a matter of debate. A recent controversy on the Middle and late Holocene sea level changes curve raised the question of the amplitude of the oscillations which occurred in the period. Also, a few but relatively consistent radiocarbon datings suggest the occurrence of a high sea level during Isotope Stage 3. In terms of sedimentary cover the Southern Brazilian shelf exhibits a very strong hydrodynamic control, both latitudinal and bathymetrical. The sector southward from 25ºS is characterized by the influence of the plume of water carrying sediments originating from the Río de La Plata. Actually its presence is conspicuous up to 28ºS, with the area between this latitude and 25ºS constituting a transitional zone. In terms of bathymetry the outer shelf is marked by the "floor-polisher" effect of the Brazil Current, which is responsible for the maintenance of a relict facies in areas deeper than 100 meters.

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Changes in the Brazilian continental margins oceanic productivity and circulation over the last 27,000 years were reconstructed based on sedimentological and microfaunal analyses. Our results suggest that oceanic paleoproductivity and the supply of terrigenous sediments to the Brazilian continental margin were higher during the Last Glacial Maximum (LGM) than during the Holocene. These changes may have been primarily influenced by significant sea level fluctuations that have occurred since the late Pleistocene. During the LGM, the lower sea level, higher productivity and lower sea-surface paleotemperatures may have been the result of the offshore displacement of the main flow of the Brazil Current. However, during the Holocene, the warm waters of the Brazil Current were displaced toward the coast. This displacement contributed to the increase in water temperature and prevented an increase in oceanic productivity. The decrease in terrigenous supply since the LGM could be related to the increase of the extension of the continental shelf and/or drier climatic conditions.

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New species are described: Tessaropa elongata sp. nov. from Brazil (Rondônia) has long elytra, a character that distinguishes it from the remaining species with short elytra; Hexoplon immaculatum sp. nov. from Ecuador (Pichincha) is characterized by the red-orange general color and black legs. Eburodacrys inaequalis sp. nov. from Bolivia (Santa Cruz) has elytral apices and same-color femora that cause it to be similar to E. ayri Martins & Galileo, 2006 and E. silviamariae Martins & Galileo, 2006, yet it differs from either species in the black lateral spines and dorsal tubercles of pronotum and the elongate eburneuos maculae of the elytra. Coleomethia bezarki sp. nov. (Costa Rica, Guanacaste) differs from C. australis Hovore, 1987 by male pronotum without rugosities, peduculate metafemora and metatibiae entirely pubescent. Bisaltes (B.) petilus sp. nov. (Costa Rica, Guanacaste, Alajuela) is separated from B. (B.)buquetii Thomson, 1868 and B. (B.) fuchsi Breuning, 1971 by the more slender body appearance, the absence of dark belts on pronotum, and the absence of circular macula in the anterior third of elytra. Notes and new records are provided for: Tetraibion concolor Martins, 2006 (Bolivia: La Paz); Gnomidolon ornaticolle Martins, 1960 (Panama: Colón); Mephritus apicatus (Linsley, 1935) (Brazil: Rondônia).

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Novas espécies descritas: Hovorelus adiectus sp. nov. (Anacolini) da Costa Rica; Stenoeme aguilari sp. nov. do Paraguai e Placoeme wappesi sp. nov. da Bolívia (Oemini); da Bahia, Brasil: Coeloxestia spinosa sp. nov. (Cerambycini, Sphallotrichina); Stizocera debilis sp. nov., Anelaphus bravoi sp. nov. (Elaphidionini) e Chydarteres formosus sp. nov. (Trachyderini).

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São descritas novas espécies de Cyrtinus LeConte, 1852: C. hispidus sp. nov. do Equador (Pichincha); C. bifasciatus sp. nov. do Panamá (Colón) e da Costa Rica, C. umbus sp. nov. (Guanacaste) e C. melzeri sp. nov. (Cartago). Acrescentam-se ocorrência e figura de C. penicillatus (Bates, 1885).

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Novas espécies descritas em Eranina Monné, 2005: E. moysesi e E. esquinas da Costa Rica; E. rondonia do Brasil (Rondônia) e E. hovorei do Equador. Acrescenta-se chave para as 34 espécies de Eranina. O gênero monotípico Eraninella gen. nov. é criado para Eranina longiscapus (Bates, 1881).

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New species described and figured: Megacyllene (M.) nevermanni sp. nov. from Costa Rica (Limón); M. (M.) punensis sp. nov. from Peru (Puno); Neoclytus fraterculus sp. nov. from Venezuela (Guárico); N. zonatus from Guatemala (Alta Verapaz); N. vitellinus sp. nov. from Costa Rica (Guanacaste); Mecometopus erratus sp. nov. from Colombia (Boyacá); M. latithorax sp. nov. from Panama (Panama).

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As seguintes novas espécies são descritas em Callini: Drycothaea gaucha sp. nov. do Rio Grande do Sul, Brasil; Callia metallica sp. nov. de Sucumbios, Equador; em Falsamblesthiini: Nyctonympha boyacana sp. nov. da Colômbia; Bactriola achira sp. nov. e Bactriola antennata sp. nov. ambas de Santa Cruz, Bolívia.

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Fundamentados em material da Universidade Estadual do Norte Fluminense (Museu de Entomologia), descreve-se em Cerambycinae, Elaphidionini: Magaliella gen. nov., espécie-tipo, M. punctata sp. nov. (Espírito Santo) e em Lamiinae, Onciderini: Oncideres hoffmanni sp. nov. (Bahia). Acrescentam-se novos registros para o Brasil: Potiaxixa intermedia (Martins, 1979) (Bahia); Appula melancholica Gounelle, 1909 (Distrito Federal), Pseudogisostola reichardti Fontes & Martins, 1977 (Rio de Janeiro), Hesycha bimaculata Martins & Galileo, 1990 (Bahia) e .Xenofrea apicalis Melzer, 1931 (Rio de Janeiro).