Artigos Científicos - ICEN

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2557

Navegar

Agora exibindo 1 - 20 de 30

Acesso aberto (Open Access)
Análise de aproximações das concepções presentes em questões associadas ao ensino de química aplicadas no novo ENEM com as concepções do enfoque CTS
(Universidade Federal do Pará, 2019-06) SOUZA, Jorge Raimundo da Trindade; BRITO, Licurgo Peixoto de
The National High School Examination (Enem) comprehends the evaluation of skills and competences fundamental to the exercise of citizenship, one of the objectives of the Science, Technology and Society (STS) approach. This qualitative research, which also adopts quantitative standards, has the objective of analyzing STS concepts in the issues associated to the chemistry teaching of this exam, in the period between 2009 to 2015 (new Enem), and the factors that influence these relations. For this, it was necessary to analyze the content and the structure of the questions associated to the teaching of Chemistry, examining if and how occurred the approximation of these questions with the principles of the STS educational perspective, and what conditions determine the mediation of this relation of proximity. As an instrument for analyzing the questions, the Discursive Textual Analysis (ATD) was used. Among the 156 analyzed questions, which are pertinent to the teaching of Chemistry, 46.1% did not present an approximation with the principles of the STS approach; 32.1% showed an apparent relationship with these assumptions and 21.8% were associated with the principles of the STS approach. The results showed that the questions of the new Enem presented proximity, at different levels, to the theoretical principles of the STS approach.
Acesso aberto (Open Access)
Assessment of surface water in two Amazonian rivers impacted by industrial wastewater, Barcarena City, Pará State (Brazil)
(2011-08) LIMA, Marcelo de Oliveira; SANTOS, Elisabeth Conceição de Oliveira; JESUS, Iracina Maura de; MEDEIROS, Adaelson Campelo; FAIAL, Kelson do Carmo Freitas; ALVES, Claudio Nahum
In 2007, surface waters were collected from 21 sampling points in Barcarena City in Northern Region of Brazil: one sampling point located in a stream that receives discharge of wastewater from a kaolin processing industry and flows into the Curuperê River, three sampling points located near sources that emerge on the left bank and flow into the Curuperê River, nine sampling points in Curuperê River, which flows into the Dendê River, and eight in Dendê River, a tributary on the right bank of the Pará River. For all water samples were quantified 14 physicochemical variables and levels of 12 metals. The results in the points near the sources of the Curuperê River presented physicochemical profile and metal levels which are typical of surface waters being used as reference to compare and identify possible changes in the chemical characteristics of the other sampling points. The comparison between the results obtained for the sources of the Curuperê River and the ones for the point near the discharge of industrial wastewater revealed strong changes in the values of 6 physicochemical variables (pH, electrical conductivity (EC), total dissolved solids (TDS), sulfate (SO4), ammoniacal nitrogen (NH4-N) and salinity) and an increase in magnitude of the levels of four metals (Al, Fe, Mn and Zn). These facts characterized that the wastewaters were discharged into the environment without adequate treatment. Results in other sampling sites showed that these anomalous conditions were also found along the Curuperê and Dendê Rivers, especially during low tide. This chemical characterization of the waters allowed to identify harmful conditions to aquatic ecosystems and potential health risk for the local people, who use the rivers for drinking water, recreation and transportation.
Acesso aberto (Open Access)
Avaliação do efeito antifúngico do óleo resina e do óleo essencial de copaíba (Copaifera multijuga Hayne)
(2011) DEUS, Ricardo Jorge Amorim de; ALVES, Claudio Nahum; ARRUDA, Mara Silvia Pinheiro
Copaifera multijuga Hayne oil in natura and its fractions were evaluated as to their fungitoxic activities against five filamentous fungus species belonging to the genus Aspergillus and three yeast species of the genus Candida. Oleoresin and essential oil concentrations ranging from 0.08 mg mL-1 to 1.6 mg mL-1 were used for qualitative and quantitative analyses. The samples were placed onto 5mm-diameter paper discs distributed on Sabouraud's medium in Petri dishes inoculated with spores of the microorganisms and incubated at 28ºC for 10 days. A solution containing 1.6 mg mL-1 miconazole nitrate was used as positive control. Qualitative results showed that the oleoresin presented good activity, while a fraction of the essential oil was highly effective against Candida parapsilosis IOC-2882, Aspergillus flavus IOC-3874 and A tamarii IOC-187 with 16.0±1.4 mm, 19.5±2.1 mm and 12.5±3.5 mm inhibition halos, respectively. The quantitative evaluation showed that 0.3 mg mL-1 oleoresin inhibited the growth of Aspergillus flavus and Candida parapsilosis, while 0.08 mg mL-1 of the essential oil fraction reached this same activity.
Acesso aberto (Open Access)
Biotransformation of sucrose into 5-hydroxy-2-hydroxymethyl-γ-pirone by Aspergillus flavus
(2010-09) FERREIRA, Nelson Rosa; SARQUIS, Maria Inez de Moura; ALVES, Claudio Nahum; SANTOS, Alberdan Silva
The sucrose hydrolysis and the preference of consumption of glucose instead of fructose were investigated for the production of 5-hydroxy-2-hydroxymethyl-γ-pyrone (HHMP) in the presence of Aspergillus flavus IOC 3974 cultivated in liquid Czapeck medium. Standardized 0.5g of pellets were transferred as inoculum into twelve conical flasks of 250 ml containing 100 ml of medium with different sucrose concentration, which was kept at 120 rpm and 28"C for 16 days without pH adjustment. Aliquots of 500μl of the broth culture were withdrawn at 24 h intervals and analyzed. The major yield of HHMP was 26g l-1 in 120g l-1 of sucrose. At these conditions, A. flavus produced an invertase capable of hydrolyzing 65% of total sucrose concentration in 24h, and an isomerase capable of converting fructose into glucose. In this work, it focused the preference for glucose and, then, of fructose by A. flavus and the strategy used to produce HHMP.
Acesso aberto (Open Access)
Characterization and distribution of pyrogenic carbon in a fraction of archaeological black earth from Caxiuanã
(2015-08) MORAES, Milena Carvalho de; LEMOS, Vanda Porpino; MORAES, Dorsan dos Santos; MORAES, Cláudio Nery Lamarão
This study aims to determine the atomic ratio of O/C in an archaeological black earth (ABE) profile of the Ilha de Terra site, a region of Caxiuanã in the Pará State, Brazil, to determine the types of pyrogenic carbon (PyC) particles and to infer the source of biomass and burning temperature necessary to produce the PyC. The O/C ratios were monitored using scanning electron microscopy combined with energy dispersive spectroscopy (SEM/EDS). The results indicated atomic ratios for clay, silt and fine sand fractions that were between those registered for the PyC particles types: condensed combustion (CC) (0.09, 0.1, 0.13), charcoal (0.32, 0.31, 0.34) and char (0.43, 0.45, 0.52). CC is the predominant type of particle found because of the high firing temperature (> 350 °C), which is consistent with the probable biomass sources of wood, cellulose and lignin.
Acesso aberto (Open Access)
Characterization of the Fruit Pulp of Camu-Camu (Myrciaria dubia) of Seven Different Genotypes and Their Rankings Using Statistical Methods PCA and HCA
(Universidade Federal do Pará, 2016-10) FREITAS, Camila Auad Beltrao de ; SILVA, Antonio dos Santos; ALVES, Claudio Nahum; NASCIMENTO, Walnice Maria Oliveira do; LOPES, Alessandra Santos; LIMA, Marcelo de Oliveira; MÜLLER, Regina Celi Sarkis
Due to the economic potential of camu-camu, considering its high concentration of vitamin C, the aim of this work was to evaluate the quality and genetic variability seven accessions of camu-camu conserved in genebank (BAG) of Embrapa Amazônia Oriental, in the state of Pará, Amazon region, Brazil. The fruits of camucamuzeiro were analyzed for physicochemical characterization (standard methodologies) and mineral composition. The data were subjected to multivariate statistical analysis, using the techniques of cluster analysis and principal component analysis. The formation of different groups for each genotype, which shows the genetic variability and the dissimilarity of the genotypes in the species data, may be used to guide the selection of promising genotypes to enrich the programs of genetic improvement of the camucamuzeiro. Ascorbic acid showed levels above 1000 mg 100 g-1, however, genotypes 4, 1 and 2 show the highest potential and the most promising nutritional capacity, but genotype 4 showed good characteristics for the moisture, acidity, carbohydrates, Cu and Zn and differs totally from others about the total soluble solids (TSS) and flavon-3-ol, features that make it the most promising genotype. It was possible to separate the seven different genotypes using multivariate analysis (hierarchical cluster analysis-HCA and principal component analysis-PCA).
Acesso aberto (Open Access)
Composição química e valor nutricional para grandes herbívoros das folhas e frutos de Aninga (Montrichardia linifera, Araceae)
(Instituto Nacional de Pesquisas da Amazônia, 2010-12) AMARANTE, Cristine Bastos do; MÜLLER, Regina Celi Sarkis; DANTAS, Kelly das Graças Fernandes; ALVES, Claudio Nahum; MÜLLER, Adolfo Henrique; PALHETA, Dulcidéia da Conceição
The aninga (Montrichardia linifera, Araceae) is often found in the floodplain ecosystems of the Amazon and is the natural diet of animals such as manatees, turtles, fish, buffalo and cattle. Aiming to contribute to the chemical knowledge and nutritional value of this plant, leaves and fruits of M. linifera were collected on the banks of the Guama and Maratauira rivers, Para State, Brazil. We determined the moisture content, ash mineral composition, lipids, protein, fiber, carbohydrate and caloric value of the fruits and leaves. The mineral composition (Ca, Mg, Cu, Fe, Zn and Mn) was obtained by flame atomic absorption spectrometry. The leaves and the fruits of M. linifera had caloric values of 289.75 kcal and 355.12 kcal, respectively; and a low protein concentration, 0.44% for leaves and 0.24% for fruits. Manganese concentrations were 3279.46 mg kg-1 for leaves and 18151.53 mg kg-1 for fruits. These Mn concentrations are considered toxic, as they exceed the maximum tolerable for the ruminants (1000 mg kg-1). The M. linifera has the capacity to absorb and bioaccumulate large amounts of Ca, Mg and Mn in the soil, which makes it inappropriate for exclusive use as food for turtles, cattle and buffaloes, requiring more studies for its application as part of the diet.
Acesso aberto (Open Access)
Densidade crítica no modelo de percolação em rede de Bethe não-homogênea
(Sociedade Brasileira de Matemática Aplicada e Computacional, 2015-08) TAVARES, Héliton Ribeiro; SOUZA, Raimundo Nonato Carneiro de; TAVARES, Maria Regina Madruga; FARIAS, Valcir Joao da Cunha
In this work we deal with an inhomogeneous Bethe lattice percolation model where the probability of an edge in level n is open changes according as n. This model can be appropriate to the case where the media changes its density in a systematic way, such as the proliferation of insects that depends on the temperature and humidity, which fluctuates between day and night. We consider the case where the density p(·) follows a function of the distance l(.) from the origin, given by a sinusoid function p(·) = p + (1 - p)|sin(l(.))|. For this model we present results of Monte-Carlo simulation showing the behavior of the probability of percolation with a second-order phase transition, but we present too a formal proof that the density is non trivial, with the mathematical expression to compute the percolation threshold.
Acesso aberto (Open Access)
Ecofisiologia de plantas jovens de mogno-africano submetidas a deficit hídrico e reidratação
(2013-01) ALBUQUERQUE, Marcos Paulo Ferreira de; MORAES, Fabrícia Kelly Cabral; SANTOS, Rodolfo Inacio Nunes; CASTRO, Gledson Luiz Salgado de; RAMOS, Edson Marcos Leal Soares; PINHEIRO, Hugo Alves
The objective of this work was to evaluate the capacity of young plants of African mahogany (Khaya ivorensis) to recover their water status and gas exchange after water deficit. Plants with approximately 315 days, irrigated (control) and non-irrigated, were evaluated after water was withheld for 14 days, and after one, three, and seven days of irrigation resumption (rehydration). On day 14, the predawn leaf water potential (Ψam) of stressed plants was reduced to -2.66 MPa. With water deficit, significant decreases were observed in predawn relative water content (32% reduction), in net assimilation rate of CO2 (90%), in stomatal conductance (95%), in transpiration (93%), and in intercellular to ambient ratio of CO2 concentration (37%). During rehydration, the water status of stressed plants was recovered after three days. Gas exchange was also recovered, but in a slower rate than water status. Under water deficit, proline concentration increased and total soluble carbohydrate concentration decreased. Young African mahogany plants are tolerant to moderate water deficit.
Acesso aberto (Open Access)
Efeito fungitóxico in vitro do óleo resina e do óleo essencial de copaíba (Copaifera multijuga Hayne)
(2009) DEUS, Ricardo Jorge Amorim de; CARVALHO, Antonio Sergio Costa; BANNA, Débora Ariane Dornelas da Silva; ARRUDA, Mara Silvia Pinheiro; ALVES, Claudio Nahum; SANTOS, Alberdan Silva
In vitro fungitoxic effect of the oil-resin and the essential oil of copaiba (Copaifera multijuga Hayne). Copaifera multijuga Hayne oil, crude and fractions, was evaluated for its in vitro fungitoxic activities against five species of filamentous fungi belonging to the genus Aspergillus and three yeast species of the genus Candida. Oil-resin and essential oil concentrations ranging from 0.008 mg mL-1 to 1.6 mg mL-1 were used in qualitative and quantitative analyses. Samples were placed onto 5mm-diameter paper disks and distributed on Saboraud culture medium in Petri dishes inoculated with conidia and incubated at 28ºC during 10 days. A solution with 1.6 mg mL-1 of miconazole nitrate was used as positive control. Qualitative results indicated that the oil-resin presented good fungistatic activity; however, one of the essential oil fractions was highly effective against Candida parapsilosis IOC-2882, Aspergillus flavus IOC-3874 and A. tamarii IOC- 187, with inhibition halos of 16.0±1.4 mm, 19.5±2.1 mm and 12.5±3.5 mm, respectively. The quantitative evaluation indicated that 0.3 mg mL-1 of the oil-resin inhibited Aspergillus flavus and Candida parapsilosis growth, whereas 0.08 mg mL-1 of the essential oil fraction reached this same activity.
Acesso aberto (Open Access)
Essential oil composition of Croton palanostigma Klotzsch from north Brazil
(2009) BRASIL, Davi do Socorro Barros; MÜLLER, Adolfo Henrique; GUILHON, Giselle Maria Skelding Pinheiro; ALVES, Claudio Nahum; ANDRADE, Eloisa Helena de Aguiar; SILVA, Joyce Kelly do Rosário da; MAIA, José Guilherme Soares
The essential oils of leaves, twigs, branches, trunk bark and fruits of Croton palanostigma were analyzed by GC and GC-MS. The main compounds found in the oil of the leaves were linalool (25.4%), (E)-caryophyllene (21.0%), methyleugenol (17.2%) and β-elemene (6.0%); in the oil of the twigs were α-pinene (41.4%), limonene (29.0%), sabinene (11.5%) and β-pinene (5.7%); in the oil of the branches were methyleugenol (24.1%), (E)-methylisoeugenol (15.3%), α-pinene (11.2%) and (E)-caryophyllene (8.5%); in the oil of the trunk bark were a-pinene (31.6%), methyleugenol (25.6%) and (E)-methylisoeugenol (23.7%); and in the oil of the fruits were linalool (42.7%), methyleugenol (16.3%) and β-elemene (6.4%). Statistical analysis showed that the leaves and fruit, and the branches and trunk bark, have significant similarities between them. In addition, the trunk bark oil has high brine shrimp larvicidal activity (LC50, 3.71 ± 0.01 mg mL-1).
Acesso aberto (Open Access)
Estudo da utilização do extrato aquoso de barbatimão (Stryphnodendron barbatimão, M.) no ensino de química
(1999) PINHEIRO, Marta Helena Tavares; LIMA, Waterloo Napoleão de
In the present work, the pH dependent colour change of the crude vegetal extracts is suggested in teaching chemical or acid-base equilibria, visual indicators and some aspects of spectrophotometric concepts its applications. The extraction methodology proposed is inexpensive and easy to perform in secondary schools and in general chemistry or instrumental undergraduate courses.
Acesso aberto (Open Access)
Estudo do crescimento de nanofitas de céria dopada com gadolínio por sistema de aquecimento por micro-ondas
(2013-09) GONÇALVES, Rosana de Fátima; CASTRO, D. A.; SANTOS, Maria Rita de Cássia; FIGUEIREDO, Alberthmeiry Teixeira de; BARRADO, Cristiano Morita; LEITE, Edson Roberto; GODINHO JÚNIOR, Mario
Cerium oxide (ceria) has attracted attention because of its important applications such as solid oxide fuel cells, catalysts for automobile exhaust gas, catalysts to obtain hydrogen, UV blockers, biomaterials, etc.. Control methods for synthesis of ceria are of great importance to explain or predict these properties. Thus, the objective of this work was to study the growth of cerium oxide nanobelts in a microwave-assisted hydrothermal system, where in 8 min 330 nm nanobelts were obtained at 130 ºC and 3 atm. The results collaborate to the research on reformers for ethanol and/or solid oxide fuel cells anode.
Acesso aberto (Open Access)
Ethanolysis optimisation of Jupati (Raphia taedigera Mart.) oil to biodiesel using response surface methodology
(2015-07) CONCEIÇÃO, Leyvison Rafael Vieira da; COSTA, Carlos Emmerson Ferreira da; ROCHA FILHO, Geraldo Narciso da; PEREIRA FILHO, Edenir Rodrigues; ZAMIAN, José Roberto
In this work, the transesterification of jupati (Raphia taedigera Mart.) oil using ethanol and acid catalyst was examined. The production of biodiesel was performed using a central composite design (CCD). A range of values for catalyst concentration (1 to 4.21%), temperature (70-80 °C), and the molar ratio of alcohol to oil (6:1-13.83:1) were tested, and ester content, viscosity, and yield were the response variables. The synthesis process was optimised using response surface methodology (RSM), resulting in the following optimal conditions for the production of jupati ethyl esters: a catalyst concentration of 3.85% at 80 °C and an alcohol-to-oil molar ratio of 10:1.
Acesso aberto (Open Access)
Flavonoids from the leaves of Deguelia utilis (Leguminosae): structural elucidation and neuroprotective properties
(2012-10) OLIVEIRA, Dalglish Gomes de; ALMEIDA, Cecília M. C. de; SILVA, Consuelo Yumiko Yoshioka e; ARRUDA, Mara Silvia Pinheiro; ARRUDA, Alberto Cardoso; LOPES, Dielly Catrina Favacho; YAMADA, Elizabeth Sumi; COSTA, Edmar Tavares da; MARTINS FILHO, Arnaldo Jorge; SILVA, Milton Nascimento da
Five new flavonoids, 5,3'-dihydroxy-4'-methoxy-2'',2''-dimethylchromene-(5'',6'':6,7)dihydroflavonol (1), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-dihydroflavonol (2), 5,3'-dihydroxy-4'-methoxy-8-allyl-2'',2''-dimethylchromene-(5'',6'':6,7) flavanone (3), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-flavanone (4), 3,5,3'-trihydroxy-7,4'-dimethoxy6,8-dimethylallyl-flavanol (5), together with the stilbenes 4-methoxylonchocarpene (6) and lonchocarpene (7) were isolated from the leaves of Deguelia utilis. Their chemical structures were established on the basis of NMR (nuclear magnetic resonance) spectral data and HRESITOF-MS (electrospray ionization-high resolution time-of-flight mass spectrometry). Also, in order to investigate potential cytoprotective effects of these flavonoids, we used a fraction eluted with hexane:EtOAc containing all seven flavonoids, in an in vitro model of neurodegeneration, using hippocampal primary cultures from neonatal (PND2-P3) rats exposed to rotenone, a mitochondrial complex I inhibitor. There was a significant reduction in cell viability (19.4 ± 1.6%) when the cultures were exposed to 30 nmol L-1 rotenone for 72 h. Concomitant exposure of the cultures to the FR3 (5 µg mL-1) and 30 nmol L-1 rotenone resulted in values of cell viability similar to control groups (99.6 ± 4.8%), strongly suggesting a cytoprotective effect for this flavonoid-rich fraction.
Acesso aberto (Open Access)
Hydrogeological Characteristic and the Vulnerability Degree of the Aquifers from Municipality of Abaetetuba, Pará - Brazil
(Universidade Federal do Pará, 2019-03) LEITE, Andreza Cristina Morais; SIQUEIRA, Gilmar Wanzeller; DARWICH, Assad José; APRILE, Fábio Marques
This study evaluated the quality of groundwater in the municipality of Abaetetuba (PA, Brazil 1°43'46'' S e 48°52'27'' W) based on the hydrogeological characterization and degree of vulnerability of the aquifer system. The municipality of Abaetetuba is practically all supplied by groundwater both by deep tubular wells and shallow pit wells (Amazonian wells), which present potential risk of contamination. Water and soils samples from 20 wells sampled between 2012 and 2016 were used. Physicochemical and microbiological analyzes served as a data base for mapping (GIS). Three hydrogeological domains were identified within the study area: Barreiras Group (predominant), Post-Barrier Sediments and Recent Sediments. Almost all of the samples presented microbiological levels above the MPV defined by the Brazilian legislation for water intended for human consumption. The DRASTIC and GOD vulnerability indexes presented values between 75 and 119 and 0.15 and 0.32 respectively, suggesting areas of 'low' to 'moderately-high' vulnerability. Local sources of pollution by coliforms have been identified due to lack of basic sanitation. Evidence of diffuse sources derived from vehicle washing and lubrication also have been identified. Although the Barreiras Group had deep semi-confined aquifers, a 'state of alert' was suggested for the areas that indicated the presence of fecal coliforms and with a high population density. Isovalues and vulnerability maps suggest areas that require further monitoring. A positive correlation between the DRASTIC Index and TDS in well water was established. The intense exploitation of groundwater especially in areas of great population density may be causing contamination of aquifers.
Acesso aberto (Open Access)
Improvement of friable callus production of Boerhaavia paniculata Rich and the investigation of its lipid profile by GC/MS
(2014-09) SOUZA, Joanne Moraes de Melo; BERKOV, Strahill; SANTOS, Alberdan Silva
In this study, a protocol to induce high amount of friable callus of Boerhaavia paniculata RICH and a lipidomics technique were applied to investigate the profile of lipids to relate to those present in the roots of this plant that presented anti-inflammatory activity in the crude hexane extract. The callus culture was induced from seeds in solidified Murashige and Skoog medium containing different amounts of glucose and different concentrations of 2,4-Dichlorophenoxyacetic acid. The explants were kept in a germination chamber at 30±2°C with a photoperiod of 16 h under light intensity of 27 µmol m–2 s–1 for 4 weeks. The best results for friable callus formation and development of the biomass were obtained in the treatment containing 2.26 µM 2.4-D and glucose (1.5 %; w/v). Lipidomics techniques were applied in hexane fraction showing higher concentrations of the steroids β-sitosterol (3.53 mg/100 g dc–dry cells), and fatty acids, especially 2-hydroxy-tetracosanoic acid (0.34 mg/100 g dc), eicosanoic acid (86.25 mg/100 g dc), stearic acid (420.83 mg/100 g dc), tetradecanoic acid (10.74 mg/100 g dc) and linoleic acid (100.61 mg/100 g dc). The lipid profile of callus versus that found in the roots of wild plant is described in this work.
Acesso aberto (Open Access)
Influência da exploração florestal de impacto reduzido sobre as fases de desenvolvimento de uma floresta de terra firme, pará, brasil
(Universidade Federal do Pará, 2013-12) FRANCEZ, Luciana Maria de Barros; CARVALHO, João Olegário Pereira de; BATISTA, Fábio de Jesus; JARDIM, Fernando Cristóvam da Silva; RAMOS, Edson Marcos Leal Soares
The influence of reduced impact logging were evaluated on the growth phases of a terra firme forest in the Paragominas region, state of Pará, that was logged considering two intensities of timber harvesting. Data were collected in 36 permanent sample plots (0.25ha) randomly distributed among treatments (T1 – Logged forest, harvesting the stem of commercial trees; T2 – Logged forest, harvesting the stem and coarse woody debris) and control (T0 unlogged forest). Three growth phases of the forest were considered: mature (DBH > 40cm); building forest (10cm < DBH < 40cm); and gaps (occurrence of a canopy gap and a few or no tree with DBH > 10cm). The homogeneity of variances of sub-plots between treatments, growth phases and years was tested by the Bonferroni test, according to the statistics of Bartlett and Levene. An analysis of variance was applied on the number of sub-plots by phases, years and treatments at a 0.005 significance level. The Tukey test was applied for analyzing the interaction between the phases and years. Before logging the percentage of growth phases were: 57.0% building forest, 38.9% mature forest and 4.1% canopy gaps. Logging reduced the areas of mature forest and building forest, increasing the number of canopy gaps, but this increase had no statistical difference. One year after logging the area of mature forest (38.4%) and building forest (53.1%) increased while the areas of gaps (8.4%) decreased. Three years after logging the percentage of mature forest (37.1%), building forest (57.9%) and gaps (5.0%) were similar to those found before logging. The forest growth phases were not influenced by logging, over the study period. The study forest showed that it is able to grow, closing the canopy gaps, even in a short period of time.
Acesso aberto (Open Access)
Isolation, X-ray crystal structure and theoretical calculations of the new compound 8-Eepicordatin and identification of others terpenes and steroids from the bark and leaves of Croton palanostigma Klotzsch
(2010) BRASIL, Davi do Socorro Barros; MÜLLER, Adolfo Henrique; GUILHON, Giselle Maria Skelding Pinheiro; ALVES, Claudio Nahum; PERIS, Gabriel; LLUSAR, Rosa; MOLINER, Vicent
Phytochemical studies of the bark and leaves of Croton palanostigma Klotzsch (Euphorbiaceae) led to the isolation of a new clerodane diterpene, 8-epicordatin (2), in addition to 12-oxohardwickiic acid methyl ester (3), aparisthman, cordatin (1), ent-trachyloban-18-oic acid, ent-13-epimanoyl oxide, ent-3-oxo-13-epimanoyl oxide, ent-3β-hydroxy-13-epimanoyl oxide, sitosterol, stigmasterol, stigmastan-3-one, 6β-hydroxystigmast-4-en-3-one, 6β-hydroxystigmasta-4,22-dien-3-one, stigmast-4-en-3-one, stigmasta-4,22-dien-3-one, 3-O-acetylaleuritolic acid, 11α-hydroxyurs-12-en-3-one, α-amyrenone, 24-methylenecycloartenone and lupenone. These compounds were isolated using typical phytochemical procedures and the structures were deduced from spectroscopic studies, including 2D NMR experiments. In addition, the crystalline structure of 8-epicordatin (2) was determined by X-ray diffraction. NMR theoretical calculations at the B3PW91/DGDZVP level were used to confirm the assignment of the chemical shifts of the H-7α and H-7β hydrogens of 8-epicordatin.
Acesso aberto (Open Access)
Maintenance of syntenic groups between Cathartidae and Gallus gallus indicates symplesiomorphic karyotypes in new world vultures
(2011) TAGLIARINI, Marcella Mergulhão; O'BRIEN, Patricia C.M.; FERGUSON-SMITH, Malcolm A.; OLIVEIRA, Edivaldo Herculano Correa de
Similarities between New World and Old World vultures have been interpreted to reflect a close relationship and to suggest the inclusion of both in Accipitridae (Falconiformes). However, deeper analyses indicated that the placement of the New World vultures (cathartids) in this Order is uncertain. Chromosome analysis has shown that cathartids retained a karyotype similar to the putative avian ancestor. In order to verify the occurrence of intrachromosomal rearrangements in cathartids, we hybridized whole chromosome probes of two species (Gallus gallus and Leucopternis albicollis) onto metaphases of Cathartes aura. The results showed that not only were the syntenic groups conserved between Gallus and C. aura, but probably also the general gene order, suggesting that New World vultures share chromosomal symplesiomorphies with most bird lineages.