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Search Results: 1 - 10 of 559608 matches for " Hérica A.;Gushikem "
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Adsorption of metal ions on novel 3-n-propyl (methylpyridinium) silsesquioxane chloride polymers surface: study of heterogeneous equilibrium at the solid-solution interface
Magosso, Hérica A.;Fattori, Natália;Kholin, Yuriy V.;Gushikem, Yoshitaka;
Journal of the Brazilian Chemical Society , 2009, DOI: 10.1590/S0103-50532009000400018
Abstract: polymers si3py+cl- (a) and si4py+cl- (b), 3-n-propyl (3-methylpyridinium) silsesquioxane and 3-n-propyl(4-methylpyridinium) silsesquioxane chlorides, respectively, were prepared by the sol-gel processing method. the ion exchange capacities (mmol g-1) were 0.90 and 0.81 for (a) and (b) respectively. considering the reaction nsipy+cl-(s) + m2+(sln) + 2cl-(sln) (sipy+)nmcl2+nn-(s), the values of the stepwise equilibrium constants obtained were: (a) cuii: logk(2)1= 4.14(0.03), logk(2)2= 2.91(0.04); znii, logk(2)1= 3.3(0.3), logk(2)2= 4.9(0.3); (b) cuii:logk(2)1= 3.82(0.03), logk(2)2= 3.00(0.04); znii, logk(2)1= 3.93(0.03), logk(2)2= 3.55(0.08), being k(2)1 and k(2)2 the equilibrium constants for adsorption of the species mcl42- and mcl3-, respectively. for adsorption of znii on si3py+cl-, k(2)2 > k(2)1, indicating positive cooperativity, i.e., the adsorption of mcl42-enhances the adsorption of mcl3- species on the adsorbent surface. for the other cations, k(2)1 > k(2)2, indicating that adsorption of mcl42-depresses the adsorption of mcl3-species, indicating negative cooperativity.
Al2O3 coated with 3-n-propyl-1-azonia-4-azabicyclo[2.2.2]octane silsesquioxane chloride and its use for immobilization of cobalt(II) tetrasulfonated phthalocyanine in oxalic acid electrooxidation
Ramos, André R.;Arguello, Jacqueline;Magosso, Hérica A.;Gushikem, Yoshitaka;
Journal of the Brazilian Chemical Society , 2008, DOI: 10.1590/S0103-50532008000400020
Abstract: a water-soluble polymer prepared by sol-gel process, 3-n-propyl-1-azonia-4-azabicyclo[2.2.2]octane silsesquioxane chloride, was adsorbed on alumina surface. this polymer-coated alumina was able to effectively immobilize cobalt(ii) tetrasulfonated phthalocyanine complexes as counter ions. cobalt phthalocyanine immobilized in this way is well and tightly adsorbed on al2o3/3-n-propyl-1-azonia-4-azabicyclo[2.2.2]octane silsesquioxane chloride surface. furthermore, when incorporated to a carbon paste electrode showed a good electrocatalytic response toward the acid oxalic oxidation, making it a suitable electrode material. a linear relationship (r = 0.998) between the current responses obtained by chronoamperometric measurements and the oxalic acid concentration in the range of 7.4 × 10-5 - 9.1 × 10-4 mol l-1 was observed. a detection limit of 18 μmol l-1 was also determined.
Concentra o sérica de leptina na síndrome dos ovários policísticos: correla o com resistência à insulina e parametros metabólicos
Mendon?a Hérica Cristina
Revista Brasileira de Ginecologia e Obstetrícia , 2001,
Abstract:
Cobalt(II) Hematoporphyrin IX immobilized in a cellulose acetate niobium(V) oxide composite membrane: preparation and oxygen reduction study
Gushikem, Yoshitaka;Campos, Elvio A.;
Journal of the Brazilian Chemical Society , 1998, DOI: 10.1590/S0103-50531998000300011
Abstract: hematoporphyrin ix [8,13,-bis(1-hydroxyethyl)-3,7,12,17-tetramethyl-21h-porphyrin-2,18-dipropionic acid] was adsorbed on the organic-inorganic composite membrane cel/nb2o5 surface. the porphyrin is strongly adhered on the nb2o5 surface by reaction of the porphyrin co2h groups with nb2o5 forming the -coo-nb chemical bond. metallation of the porphyrine ring was made very easily by immersing the membrane in co(ii) solution and allowing to rest for a few hours. the electronic absorption bands due to the q bands indicated the symmetry change from d2h to d4h upon metallation of the porphyrin ring. the chemical analyses of the material confirmed that the metallation yield was practically 100%. oxygen was reduced on a electrode surface made with the material under a cathodic peak potential of -390 mv, in 1 m kcl solution at ph 1, temperature of 298 k and at ambient pressure. the oxygen reduction was proposed to occur by a two electron transfer mechanism. a linear cathodic peak current response was obtained for dissolved oxygen concentrations between 1.5 and 15 ppm.
Cobalt(II) Hematoporphyrin IX immobilized in a cellulose acetate niobium(V) oxide composite membrane: preparation and oxygen reduction study
Gushikem Yoshitaka,Campos Elvio A.
Journal of the Brazilian Chemical Society , 1998,
Abstract: Hematoporphyrin IX [8,13,-bis(1-hydroxyethyl)-3,7,12,17-tetramethyl-21H-porphyrin-2,18-dipropionic acid] was adsorbed on the organic-inorganic composite membrane Cel/Nb2O5 surface. The porphyrin is strongly adhered on the Nb2O5 surface by reaction of the porphyrin CO2H groups with Nb2O5 forming the -COO-Nb chemical bond. Metallation of the porphyrine ring was made very easily by immersing the membrane in Co(II) solution and allowing to rest for a few hours. The electronic absorption bands due to the Q bands indicated the symmetry change from D2h to D4h upon metallation of the porphyrin ring. The chemical analyses of the material confirmed that the metallation yield was practically 100%. Oxygen was reduced on a electrode surface made with the material under a cathodic peak potential of -390 mV, in 1 M KCl solution at pH 1, temperature of 298 K and at ambient pressure. The oxygen reduction was proposed to occur by a two electron transfer mechanism. A linear cathodic peak current response was obtained for dissolved oxygen concentrations between 1.5 and 15 ppm.
Bem-estar na produ??o de frango de corte em diferentes sistemas de cria??o
Nazareno, Aérica C;Pandorfi, Héliton;Guiselini, Cristiane;Vigoderis, Ricardo B;Pedrosa, Elvira M. R;
Engenharia Agrícola , 2011, DOI: 10.1590/S0100-69162011000100002
Abstract: this research was carried out to evaluate different housing systems for broiler chickens production, characterizing the thermal environment, physiological parameters and animal behavior. the experiment was conducted in a production cycle of 42 days, in the city of carpina, state of pernambuco, brazil, at the experimental station for small animals of the federal rural university of pernambuco (ufrpe). the survey was developed in production module divided into 15 boxes with 10 birds per box and density of the 10 birds per m2, totaling 150 birds, submitted to the three housing systems: semi-confined with 3m2 per broiler of paddock area (sc 3), semi-confined with 6m2 per broiler of paddock area (sc 6) and total confinement (conf). the experimental design for data general analysis was completely randomized (crd), in split plots, being the weeks allocated in the plots and the accommodation systems (sc 3, sc 6, conf and ext) in the sub-plots with the averages compared through the tukey test. the meteorological variables, comfort indexes and physiological parameters indicated the semi-confined system of accommodation sc 3 as one that allowed better natural conditioning heat to the birds, presenting the average values of 25.4oc, 69.9 kj kg-1, 75.7, 65.12 movements min-1 and 41.92oc for dry bulb temperature, enthalpy, black globe humidity index, respiratory rate and cloacal temperature, respectively. the birds subjected to the semi-confined system sc 3 were those that had better opportunity to express their natural behavior and explore the external environment to the module of production, leveraging the animal welfare.
Porphyrinosilica and metalloporphyrinosilica: hybrid organic-inorganic materials prepared by sol-gel processing
IAMAMOTO, YASSUKO;SACCO, HéRICA C.;BIAZZOTTO, JULIANA C.;CIUFFI, KATIA J.;SERRA, OSVALDO A.;
Anais da Academia Brasileira de Ciências , 2000, DOI: 10.1590/S0001-37652000000100008
Abstract: new materials porphyrinosilica and metalloporphyrinosilica template have been obtained by a sol-gel processing where functionalyzed porphyrins and metalloporphyrins "building blocks" were assembled into a three-dimensional silicate network. the optimized conditions for preparation of these materials are revised. the monomer precursors porphyrinopropylsilyl and metalloporphyrinopropylsilyl preparation reactions and subsequent one pot sol-gel processing with tetraethoxysilane are discussed. in the case of metalloporphyrins the nitrogen base coordinates to the central metal and acts as a template in the molecular imprinting technique. uv-visible absorption spectroscopy, thermogravimetric analysis, electron paramagnetic resonance, nuclear magnetic spectra, infrared spectra, luminescence spectra, surface area and electron spectroscopy imaging of the materials are used to characterize the prepared materials. the catalytic activities of these metalloporphyrinosilica- template are compared.
Induced response against herbivory by chemical information transfer between plants
Campos, Wellington G.;Faria, Ana P.;Oliveira, Maria Goreti A.;Santos, Hérica L.;
Brazilian Journal of Plant Physiology , 2008, DOI: 10.1590/S1677-04202008000400001
Abstract: plants respond to herbivores and pathogens attack with increased emission of volatile organic compounds. these molecules act as indirect defences when attracting natural enemies of herbivores and thus benefit the plant. it remains controversial whether undamaged plants capture chemicals released by damaged neighbouring plants and respond to them by increasing their defensive barriers against an imminent attack. in spite of public appeal and of this being the 25th year of the talking trees hypothesis, only recently have the most sceptical scientists been convinced. the induced response to herbivory by interplant information transfer has been found in two plant-herbivore systems. however, the universality of the phenomenon and its ecological and evolutionary relevance remain unclear. the integration of molecular biology, biochemistry, physiology, and ecology begin to shed light on the mechanisms of the signal transfer. this integrative approach has developed new and more sensitive tools for identification of complex volatile mixtures and for understanding the process of biosynthesis, emission, transportation and reception of signals.
Frequency of eosinophilia and risk factors and their association with Toxocara infection in schoolchildren during a health survey in the north of Lima, Peru
Roldán, William H.;Espinoza, Yrma A.;Atúncar, Arturo;Ortega, Emperatriz;Martinez, América;Saravia, Melissa;
Revista do Instituto de Medicina Tropical de S?o Paulo , 2008, DOI: 10.1590/S0036-46652008000500005
Abstract: during a health survey in a primary school from the district of carabayllo (north of lima, peru), 200 schoolchildren (96 male and 104 female between five to 12 years old) were randomly selected and divided in two groups (as positive or negative group), according to the serologic result of the toxocara elisa test from a total population of 646 schoolchildren. all children were analyzed by hematologic tests to determinate the frequency of eosinophilia and leukocytosis. additionally, all clinical and epidemiological data were also analyzed to determine their association with toxocariasis. from group of children with positive serology, 40% had some type of eosinophilia in contrast to 19% of children with negative serology, and their association was statistically significant (or = 2.84, p < 0.001). from all signs and symptoms evaluated, only 'dry cough' was more frequent and statistically significant in the positive serology group (or = 2.79, p < 0.001). almost all risk factors evaluated were highly frequent and statistically associated to the positive serology. in conclusion, the presence of eosinophilia and the risk factors evaluated in this population were frequently associated to human toxocariasis.
Heat Treatment and Thirty-Day Storage Period Do Not Affect the Stability of Omega-3 Fatty Acid in Brown Flaxseed (Linum Usitatissimum) Whole Flour  [PDF]
Dayane de C. Morais, érica A. Moraes, Maria Inês de S. Dantas, Júlia C. C. Carraro, Cassiano O. da Silva, Paulo R. Cecon, Hércia S. Duarte Martino, S?nia M. Rocha Ribeiro
Food and Nutrition Sciences (FNS) , 2011, DOI: 10.4236/fns.2011.24040
Abstract: This study was conducted to verify if the processing and storage of brown flaxseed whole flour result in loss of func-tional properties, such as reduced linolenic acid content, increased lipid peroxidation and sensory changes. The flours were obtained from seeds dried by heat treatment in oven at 150?C, for 15 minutes and subsequent grinding to obtain flour with a particle size of 20 mesh. Meal samples, with and without synthetic antioxidants (BHA and BHT combined, at 100 ppm each), were stored for a thirty-day period, under similar conditions to those used commercially. The linolenic acid content was quantified by gas chromatography. Lipid peroxidation was analyzed by thiobarbituric acid reactive substance assay. Color and flavor were evaluated by sensory tests. The linolenic acid content and lipid peroxidation did not significantly change after processing or during storage. Fluctuations in color and flavor occurred during storage, but at the end of 30 days, only the heat treatment presented negative effect (p < 0.05) on the parameter color. Heat treatment and thirty-day storage period do not change the stability of n-3 fatty acid in brown flaxseed whole flour.
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