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Search Results: 1 - 10 of 489345 matches for " Santos C. P. F. dos "
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Caracteriza??o e usos de argilas bentonitas e vermiculitas para adsor??o de cobre (II) em solu??o
Santos, C. P. F. dos;Melo, D. M. A.;Melo, M. A. F.;V. Sobrinho, E.;
Ceramica , 2002, DOI: 10.1590/S0366-69132002000400002
Abstract: mineral clays have been extensively used for metal removal. the process involves precipitation, ion exchange and adsorption. the present investigation assessed the adsorption of cu (ii) solution by natural vermiculite and both natural and synthetic bentonite. tests were carried out at ambient temperature for the main parameters of the process, i.e., ph, contact time, and adsorbent content. atomic absorption was also carried out both for the floater and solid residue. all raw materials used herein, i.e., sodic bentonite from campina grande-pb, sodic bentonite from wyoming-usa, synthetic sodic bentonite and vermiculite from piaui, were characterized both before and after adsorption of cu (ii) solution by chemical analysis, tg, dta, bet surface area, infrared spectroscopy, x-ray diffraction, and ph determination. the results showed that clay minerals adsorb heavy metals by ionic exchange. vermiculite was the most efficient material studied adsorbing 40.9% of cu solution.
Caracteriza o e usos de argilas bentonitas e vermiculitas para adsor o de cobre (II) em solu o
Santos C. P. F. dos,Melo D. M. A.,Melo M. A. F.,V. Sobrinho E.
Ceramica , 2002,
Abstract: Vários trabalhos tratam da remo o de metais por argilas e argilominerais. O processo de remo o geralmente ocorre por precipita o, troca i nica e adsor o. Neste trabalho estudou-se a adsor o de solu o de Cu (II) em vermiculita, bentonitas sódica e cálcica, proveniente de Campina Grande-PB , tendo-se como variáveis pH, tempo de contato e concentra o do adsorvente. Os ensaios foram realizados à temperatura ambiente e as medidas de Absor o At mica foram feitas no sobrenadante e no resíduo sólido. As argilas bentonitas cálcicas, provenientes de Campina-Grande (PB), sódica de Wyoming (Wyoming-USA) e sódicas (preparadas em laboratório) e as vermiculitas (provenientes do Piauí) foram caracterizadas antes e após o processo de adsor o de Cu (II) em solu o através das técnicas, análise química, TG e DTA, área superficial (BET), espectroscopia na regi o de infravermelho, difra o de raios X e medidas de pH. Os resultados mostram que as argilas estudadas adsorvem metais pesados através da troca i nica e que a vermiculita foi mais eficaz no processo, adsorvendo 40,9% de cobre da solu o em estudo, em rela o às outras argilas envolvidas no processo.
Molecular characterization of the hexose transporter gene in benznidazole resistant and susceptible populations of Trypanosoma cruzi
dos Santos Paula F,Ruiz Jer?nimo C,Soares Rodrigo P P,Moreira Douglas S
Parasites & Vectors , 2012, DOI: 10.1186/1756-3305-5-161
Abstract: Background Hexose transporters (HT) are membrane proteins involved in the uptake of energy-supplying glucose and other hexoses into the cell. Previous studies employing the Differential Display technique have shown that the transcription level of the HT gene from T. cruzi (TcrHT) is higher in an in vitro-induced benznidazole (BZ)-resistant population of the parasite (17 LER) than in its susceptible counterpart (17 WTS). Methods In the present study, TcrHT has been characterized in populations and strains of T. cruzi that are resistant or susceptible to BZ. We investigated the copy number and chromosomal location of the gene, the levels of TcrHT mRNA and of TcrHT activity, and the phylogenetic relationship between TcrHT and HTs from other organisms. Results In silico analyses revealed that 15 sequences of the TcrHT gene are present in the T. cruzi genome, considering both CL Brener haplotypes. Southern blot analyses confirmed that the gene is present as a multicopy tandem array and indicated a nucleotide sequence polymorphism associated to T. cruzi group I or II. Karyotype analyses revealed that TcrHT is located in two chromosomal bands varying in size from 1.85 to 2.6 Mb depending on the strain of T. cruzi. The sequence of amino acids in the HT from T. cruzi is closely related to the HT sequences of Leishmania species according to phylogenetic analysis. Northern blot and quantitative real-time reverse transcriptase polymerase chain reaction analyses revealed that TcrHT transcripts are 2.6-fold higher in the resistant 17 LER population than in the susceptible 17 WTS. Interestingly, the hexose transporter activity was 40% lower in the 17 LER population than in all other T. cruzi samples analyzed. This phenotype was detected only in the in vitro-induced BZ resistant population, but not in the in vivo-selected or naturally BZ resistant T. cruzi samples. Sequencing analysis revealed that the amino acid sequences of the TcrHT from 17WTS and 17LER populations are identical. This result suggests that the difference in glucose transport between 17WTS and 17LER populations is not due to point mutations, but probably due to lower protein expression level. Conclusion The BZ resistant population 17 LER presents a decrease in glucose uptake in response to drug pressure.
Effects of tryptophan depletion on anxiety induced by simulated public speaking
Monteiro-dos-Santos P.C.,Graeff F.G.,dos-Santos J.E.,Ribeiro R.P.P.
Brazilian Journal of Medical and Biological Research , 2000,
Abstract: Several lines of evidence point to the participation of serotonin (5HT) in anxiety. Its specific role, however, remains obscure. The objective of the present study was to evaluate the effect of reducing 5HT-neurotransmission through an acute tryptophan depletion on anxiety induced by a simulated public speaking (SPS) test. Two groups of 14-15 subjects were submitted to a 24-h diet with a low or normal content of tryptophan and received an amino acid mixture without (TRY-) or with (TRY+) tryptophan under double-blind conditions. Five hours later they were submitted to the SPS test. The state-trait anxiety inventory (STAI) and the visual analogue mood scale (VAMS) were used to measure subjective anxiety. Both scales showed that SPS induced a significant increase in anxiety. Although no overall difference between groups was found, there was a trend (P = 0.078) to an interaction of group x gender x phases of the SPS, and a separate analysis of each gender showed an increase in anxiety measured by the STAI in females of the TRY- group. The results for the female TRY- group also suggested a greater arousing effect of the SPS test. In conclusion, the tryptophan depletion procedure employed in the present study did not induce a significant general change in subjective anxiety, but tended to induce anxiety in females. This suggests a greater sensitivity of the 5HT system to the effects of the procedure in this gender.
Variabilidade espacial e temporal da precipita??o pluvial na bacia hidrográfica do Ribeir?o Jo?o Leite-GO
Santos, Eduardo H. M. dos;Griebeler, Nori P;Oliveira, Luiz F. C. de;
Engenharia Agrícola , 2011, DOI: 10.1590/S0100-69162011000100008
Abstract: the pluvial precipitation is the main hydrology variable input in the hydrological cycle and the knowledge of their spatial and temporal behavior is basic material for hydrological studies, watershed and water resource management, among others. the surface water produced in this basin is essential to the development of the axis anápolis-goiania-brasília and recently, with the increasing of water demand, it has been reported conflicts by the water use. thus, it appears that the development of hydrological studies aimed for better understanding and utilization of water resources are strategic for the development of the region. in this way, this work purpose to map the average monthly and annual precipitation in the jo?o leite watershed, using geostatistical techniques. it was evaluated the spherical, exponential and gaussian semivariogram models, adjusted by the weighted least squares method, being the model used for mapping by kriging the one that produced the lowest average error indicated by cross validation. it was found a good performance of geostatistical techniques in mapping the average monthly and annual precipitation, indicated by small errors, which can be highlighted the exponential model, with the best results in the most of the studied events.
Efeito das intera??es hiperconjugativas na constante de acoplamento 1J CH da hexametilenotetramina e do adamantano: estudo teórico e experimental
Santos, Francisco P. dos;Ducati, Lucas C.;Tormena, Cláudio F.;Rittner, Roberto;
Química Nova , 2007, DOI: 10.1590/S0100-40422007000700035
Abstract: the objective of this work was to determine the influence of hyperconjugative interactions on the 1jch coupling constant for hexamethylenetetramine (1) and adamantane (2). for this end, theoretical and experimental 1jch were obtained and hyperconjugative interactions were investigated using nbo. it was observed, theoretically and experimentally, that 1jch in 1 is 20 hz larger than in 2, mainly due to the nn?s*c-h hyperconjugative interaction. this interaction occurs only in 1, with an energy of 9.30 kcal mol-1. it increases the s-character of the carbon atom in the c-h bond and the occupancy of the s*c-h orbital in (1).
Rela??o entre uso do solo e comportamento hidrológico na Bacia Hidrográfica do Ribeir?o Jo?o Leite
Santos, Eduardo H. M. dos;Griebeler, Nori P.;Oliveira, Luiz F. C. de;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2010, DOI: 10.1590/S1415-43662010000800006
Abstract: the hydrological behavior of watersheds derives mainly from climate variability and land use. the 'ribeir?o jo?o leite' watershed is the main sourse of water supply in goiania city, and recently intense modifications were observed in the land use and availability of water. in this context, this work proposes to classify the land use between 1979 and 2005 and establish the association of the runoff with the land use and climate variability. for this, landsat images from the years 1979, 1989, 1997 and 2005 were used as well as flow and rainfall data provided by the agência nacional de água (ana). the land use was marked by 17.8% of deforestation, expansion of the urbanization and agriculture corresponded to 6.6 and 15.2%, respectively, and by significant areas of pasture. a trend of reduction in flow was observed that could be explained, in part, by a reduction in the rainfall regime. however, due to the significant increase of water withdrawal and the lack of historical records, there was difficulty in qualitative association between the runoff and the land use in spite of generating linear regression models with coefficients of determination (r2) above 0.75.
Efeito do início de ocorrência do míldio na produ o de frutos do meloeiro
Santos A. Apoliano dos,Cardoso J. Emilson,Vidal Julio C.,Viana F. Marto P.
Fitopatologia Brasileira , 2003,
Abstract: O míldio, causado por Pseudoperonospora cubensis, é a principal doen a fúngica da cultura do meloeiro (Cucumis melo) no período chuvoso nas regi es produtoras do Nordeste brasileiro, e para o seu controle s o realizadas até dez aplica es de fungicidas. O estabelecimento de sistemas de previs o de danos causados por esta doen a requer uma estimativa sob várias situa es epidêmicas. Os danos causados pelo míldio à produ o de frutos do meloeiro, levando-se em considera o o início do aparecimento dos sintomas e o estádio de desenvolvimento da planta, foram determinados em três experimentos de campo. Utilizou-se a aplica o de uma das misturas fungicidas tiofanato metílico + clorotalonil ou metalaxyl + mancozeb no estabelecimento de menores intensidades de míldio. Houve uma significativa redu o do rendimento de frutos quando a doen a teve início aos 24 e 36 dias, porém, quando a doen a iniciou-se aos 47 dias, nenhum efeito na produ o foi observado. Concluiu-se que os aspectos relacionados com a dura o e, notadamente, com o início da epidemia, em rela o ao ciclo do hospedeiro, devem ser considerados no estabelecimento de modelos de prognósticos de danos à produ o.
Experimental analysis of lateral impact on planar brittle material
F. P. M. dos Santos,V. C. Barbosa,R. Donangelo,S. R. Souza
Physics , 2009, DOI: 10.1103/PhysRevE.81.046108
Abstract: The fragmentation of alumina and glass plates due to lateral impact is studied. A few hundred plates have been fragmented at different impact velocities and the produced fragments are analyzed. The method employed in this work allows one to investigate some geometrical properties of the fragments, besides the traditional size distribution usually studied in former experiments. We found that, although both materials exhibit qualitative similar fragment size distribution function, their geometrical properties appear to be quite different. A schematic model for two-dimensional fragmentation is also presented and its predictions are compared to our experimental results. The comparison suggests that the analysis of the fragments' geometrical properties constitutes a more stringent test of the theoretical models' assumptions than the size distribution.
Distribui??o e amostragem de Sitophilus zeamais (M.) em gr?os de trigo armazenado em silo metálico
Santos, Anderson K.;Faroni, Lêda R. D?Antonino;Santos, Jamilton P. dos;Guedes, Raul N. C.;Rozado, Adriano F.;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2003, DOI: 10.1590/S1415-43662003000300017
Abstract: the objective of this work was to determine the type of distribution of sitophilus zeamais (mostch., 1895) in a grain mass and to estimate the number of samples required for design of monitoring program for the insect-pest. a metallic bin filled with 12,5 t of wheat (type durum; harvested in sept. 1998) was utilized. the wheat was infested with s. zeamais during the bin loading to obtain 1 insect kg-1 of grains. grain sampling at three depths was carried out every eight days for three months. after weighing, the grain samples were sieved to isolate and allow insect counting. in order to characterize the type of the distribution of the sitophilus population, three techniques were used: iwao?s patchness, taylor?s power law and morisita?s index. despite iwao?s and taylor?s techniques providing the same distribution characterization, iwao?s technique was preferred because it is less affected by sample size, location and sampling intervals. the determination of the number of samples was based on the mean number of insects collected per sample. the results obtained indicated that a smaller number of sample is required for the detection of high insect densities.
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