22 resultados para Partition of unity implicits
em Scielo Saúde Pública - SP
Resumo:
A full two-level factorial design was employed to study the influence of PEG molar mass (MM PEG), PEG concentration (C PEG) and phosphate concentration (C PHOSPH) on proteases partition by Lentinus citrinus DPUA 1535 in a PEG/phosphate aqueous two-phase system (ATPS). For all ATPS studied, proteases partitioned for the top phase and the best proteases extraction condition was obtained with MM PEG = 6000 g mol-1, C PEG = 17.5% (w/w) and C PHOSPH = 25% (w/w) with (1.1) purification factor and (151%) activity yield. Findings reported here demonstrate a practical strategy that serves as a first step for proteases purification from crude extract by L. citrinus.
Resumo:
The chloroform partition of methanol extract of leaves of Caesalpinia pyramidalis was submitted to different chromatographic procedures which afforded besides agathisflavone and taxifolin, the minor biflavones loniflavone, amentoflavone, 5'- hydroxyamentoflavone and podocarpusflavone A. The structures of the compounds were established on the basis of NMR and MS data analysis. Besides, the content of biflavones of different specimens of C. pyramidalis, which are collected in different habitats of the Brazilian semi-arid region, was determinated by LC-APCI-MS analysis. These analysis demonstrated that only the specimens harvested in Bahia state showed collectively the presence of agathisflavone, amentoflavone, sequoiaflavone and podocarpusflavone A.
Resumo:
The biological activity of seven extracts from leaves of different Jatropha curcas L (Euphorbiaceae) accessions was evaluated on Spodoptera frugiperda. Methanol extracts were incorporated into an artificial diet and offered to the larval stage of S. frugiperda. The parameters evaluated were length of larval and pupal stages, mortality of larval and total cycle stage, and weight of pupae. The extracts of the EMB accessions showed the best result for larval mortality at 60.00 and 56.67%, compared with the control, respectively. Hexane partition of the methanol extract of the leaves of PM-14 accessions allowed the identification of phytosterols, phytol and n-alkanols.
Climate, soil and tree flora relationships in forests in the state of São Paulo, southeastern Brasil
Resumo:
ABSTRACT - (Climate, soil and tree flora relationships in forests in the state of São Paulo, southteastern Brasil). With the aim of verifying possible influences of abiotic features on the spatial distribution of forest tree species and families, thirteen surveys in the state of São Paulo were selected, representing different conditions (localization at the extreme coordenates and altitudes, succesional stages, surveying methods). By applying Jaccard's Index to the binary matrices of 806 synonymized specific binomina and 79 families (Cronquist's system) phenograms were constructed using the method of the unweighted pair grouping by mathematical average (UPGMA). The species formed two floristic blocks: hygrophyllous (yearly rainfall greater than 2000 mm without dry season) and mesophyllous (yearly rainfall about 1400 mm with variable dry season). The latter was divided in two other groups: the high-altitudinal (median altitudes higher than 750 m, frost average frequency greater than 3 days/year) and low-altitudinal. Both mesophyllous floristic blocks were subdivided according to soil conditions (texture, eutrophism, acid or allic dystrophism, iron content). At the family level the relations were weak, but also showed the soil nutritional status as a possible constraint to the spatial partition of families.
Resumo:
Programmed cell death in the form of apoptosis involves a network of metabolic events and may be triggered by a variety of stimuli in distinct cells. The nervous system contains several neuron and glial cell types, and developmental events are strongly dependent on selective cell interactions. Retinal explants have been used as a model to investigate apoptosis in nervous tissue. This preparation maintains the structural complexity and cell interactions similar to the retina in situ, and contains cells in all stages of development. We review the finding of nuclear exclusion of several transcription factors during apoptosis in retinal cells. The data reviewed in this paper suggest a link between apoptosis and a failure in the nucleo-cytoplasmic partition of transcription factors. It is argued that the nuclear exclusion of transcription factors may be an integral component of apoptosis both in the nervous system and in other types of cells and tissues.
Resumo:
Knowledge about the fate of fertilizer nitrogen in agricultural systems is essential for the improvement of management practices in order to maximize nitrogen (N) recovery by the crop and reduce N losses from the system to a minimum. This study involves fertilizer management practices using the 15N isotope label applied in a single rate to determine the fertilizer-N balance in a particular soil-coffee-atmosphere system and to deepen the understanding of N plant dynamics. Five replicates consisting of plots of about 120 plants each were randomly defined within a 0.2 ha coffee plantation planted in 2001, in Piracicaba, SP, Brazil. Nine plants of each plot were separated in sub-plots for the 15N balance studies and treated with N rates of 280 and 350 kg ha-1 during 2003/2004 and 2004/2005, respectively, both of them as ammonium sulfate enriched to a 15N abundance of 2.072 atom %. Plant shoots were considered as separate parts: the orthotropic central branch, productive branches, leaves of productive branches, vegetative branches, leaves of vegetative branches and fruit. Litter, consisting of dead leaves accumulated below the plant canopy, was measured by the difference between leaves at harvest and at the beginning of the following flowering. Roots and soil were sampled down to a depth of 1.0 at intervals of 0.2 m. Samples from the isotopic sub-plots were used to evaluate total N and 15N, and plants outside sub-plots were used to evaluate dry matter. Volatilization losses of NH3 were estimated using special collectors. Leaching of fertilizer-N was estimated from deep drainage water fluxes and 15N concentrations of the soil solution at 1 m soil depth. At the end of the 2-year evaluation, the recovery of 15N applied as ammonium sulfate was 19.1 % in aerial plant parts, 9.4 % in the roots, 23.8 % in the litter, 26.3 % in the fruit and 12.6 % remaining in the 0_1.0 m soil profile. Annual leaching and volatilization losses were very small (2.0 % and 0.9 %, respectively). After two years, only 6.2 % N were missing in the balance (100 %) which can be attributed to other non-estimated compartments and experimental errors. Results show that an enrichment of only 2 % atom 15N allows the study of the partition of fertilizer-N in a perennial crop such as coffee during a period of two years.
Resumo:
A mixture containing sitosterol and stigmasterol; a new triterpene 3-epi-ursolic acid; another triterpene mixture comprising a-amyrin, b-amyrin and lupeol; verbascoside, a phenylpropanoid glycoside; and lespedin, a glycosyl flavonoid, were isolated. The less polar compounds (steroids and triterpenoids) were isolated from the hexane partition of the crude ethanolic extract while the more polar ones (phenylpropanoid glycoside and glycosyl flavonoid) were isolated from the ethyl acetate partition of the same extract. The structures of all compounds were established using modern spectrometric methods of elucidation. The spectroscopic data of Lespedin, a rare dirhamnosylflavonol with hypotensor activity and of the triterpene, 3-epi-ursolic acid, are also reported.
Resumo:
The AVS is defined operationally as acid volatile sulfide, which is a controlling phase on the partition of some metallic species in sediments. A Factorial design was evaluated by means of 16 experiments and using four variables: temperature, extraction time, N2 flow, and volume of the S2- collection solution. The factors that contributed to the efficiency of the process were the extraction time and the N2 flow. Trapping of S2- was efficient in AAB. The S2- was quantified using a potentiometric procedure. Recovery tests for S2- concentrations varying from 1×10-5 to 1×10-4 mol L-1 were in the range from 93 to 116%.
Resumo:
The use of fatty acids (FAs) as amphiphiles is very important because they have a behaving similar to surfactants. The formulation for the preferential partition of these species was studied by varying the amount of salt at constant acid concentration. As the salt concentration increases, a Winsor I→III→II transition is observed for all the systems studied. Furthermore, the electrolyte concentration required to obtain the optimum formulation varies inversely with the chain length of the acid. The partition coefficient of the surfactant allows one to obtain thermodynamic information on the acid transfer process between the phases of the system.
Resumo:
Abstract In this article we analyze two different perceptions of border inside Europe. On the one hand, we have the perception idealized by the European Union as an international organization, which believes that states benefit more from cooperation and dilution of borders in a common space than from keeping its borders as a symbol of its sovereignty. On the other hand, we have the European member states, taken individually, with particular interests and goals that, given the threat of illegal immigration, which is currently felt in the large-scale Europe, adopt a realistic perception of the border, and look at each territory as a space that needs protection from external threats. Following this argument, we reason that the current construction of walls in several European countries reflects the rebirth of a realistic perception of the border, and this is one more challenge for Europe regarding its unity and solidarity. Is this the end of the Schengen Agreement? What is going to happen to the European project if each state unilaterally adopts a strategy to deal with illegal immigration and refugees that are coming to Europe? Can immigration lead to a retrocession of the EU idealist significance of border?
Resumo:
A particular event concerning a Swan-Ganz catheter complication is reported. A 41-year-old woman was admitted at the emergency room of our hospital with massive gastrointestinal bleeding. A total gastrectomy was performed. During the postoperative period in the intensive care unit , the patient maintained hemodynamic instability. Invasive hemodynamic monitoring with a pulmonary artery catheter was then indicated. During the maneuvers to insert the catheter, a true knot formation was identified at the level of the superior vena cava. Several maneuvers by radiological endovascular invasive techniques allowed removal of the catheter. The authors describe the details of this procedure and provide comments regarding the various techniques that were employed in overcoming this event. A comprehensive review of evidence regarding the benefits and risks of pulmonary artery catheterization was performed. The consensus statement regarding the indications, utilization, and management of the pulmonary artery catheterization that were issued by a consensus conference held in 1996 are also discussed in detail.
Resumo:
During the past fifteen years, African Strychnos species have been pharmacologically and chemically screened by some European Universities, sometimes with the collaboration of some African Institutes. Strychnos usambarensis will be discussed here because of our interest in it, after the discovery of its use in the preparation arrow poison with curarizing activity.The European studies have show thah the African species of Strychnoschemically are very similar to certain South-American species. Indeed, the occurrence in the African species of curarizing quaternary bases, and in the American species of tetanizing tertiary bases, such as akagerine, emphasizes the unity of genus Strychnos in terms of it alkaloids. Many biological activities (antmicrobial, hypotensive, smasmolytic, amoebicial...) have been detected.Finally, the antimitotic properties of some alkaloids will be presented. Besides know antitumor drugs, e.g. alstonine and ellipticine, African species possess new antimitotic products, e.g. strychnopentamine present in Strychnos usambarensis.Because of these findings, the main reasons why further investigate Brazilian Strychnos species are the lack of knowledge about:- the distribution on the species in the southern part of the great Amazon Basin.Accordin to Krukoff, it is possible that new species may be found there.- the distribution of alkaloids in many of know species. Indeed, there is little information on the variation in compposition of the alkaloidal mixtures in the different parts of the plants.- the biological of alkaloids. In the past, interest has been focused too narrowly on possible curarizing properties.Why should Brazilian species not cantain alkaloids with properties similar to those found in the African species?
Ecogenetics of Triatoma sordida and Triatoma guasayana (Hemiptera: Reduviidae) in the Bolivian Chaco
Resumo:
Triatoma guasayana and two putative cryptic species pertaining to T. sordida complex (named groups 1 and 2) occur in sympatry in the Bolivian Chaco. Using multilocus enzyme electrophoresis and subsequent genetic analysis, our work assesses their population distribution and dispersal capacity in domestic, peridomestic, and silvatic environments. Our collections by light trap in the silvatic environment indicated a predominance of T. guasayana and T. sordida group 2 and a lesser abundance of T. sordida group 1 (£ 10% of the total of captures). Their similar distribution in two silvatic areas 80 km apart supports the hypothesis of their homogeneous dispersal through the Bolivian Chaco. The distribution of T. guasayana and T. sordida groups 1 and 2 was similar between silvatic environment and peridomestic ecotopes where 25% of positive places was occupied by two or three species. Bromeliads were confirmed as favorable shelter for T. guasayana but were free of T. sordida. T. sordida group 1 and to a lesser extent T. guasayana would be more invasive vectors for houses than T. sordida group 2. The spatial partition in the three species sampled in two distant sites suggested a reduced dispersive capacity.
Resumo:
A pseudogene, designated as "ps(5.8S+ITS-2)", paralogous to the 5.8S gene and internal transcribed spacer (ITS)-2 of the nuclear ribosomal DNA (rDNA), has been recently found in many triatomine species distributed throughout North America, Central America and northern South America. Among characteristics used as criteria for pseudogene verification, secondary structures and free energy are highlighted, showing a lower fit between minimum free energy, partition function and centroid structures, although in given cases the fit only appeared to be slightly lower. The unique characteristics of "ps(5.8S+ITS-2)" as a processed or retrotransposed pseudogenic unit of the ghost type are reviewed, with emphasis on its potential functionality compared to the functionality of genes and spacers of the normal rDNA operon. Besides the technical problem of the risk for erroneous sequence results, the usefulness of "ps(5.8S+ITS-2)" for specimen classification, phylogenetic analyses and systematic/taxonomic studies should be highlighted, based on consistence and retention index values, which in pseudogenic sequence trees were higher than in functional sequence trees. Additionally, intraindividual, interpopulational and interspecific differences in pseudogene amount and the fact that it is a pseudogene in the nuclear rDNA suggests a potential relationships with fitness, behaviour and adaptability of triatomine vectors and consequently its potential utility in Chagas disease epidemiology and control.