Thermal study and physico-chemical characterization of some functional properties of guava seeds protein isolate (Psidium guajava)

The guava seed protein isolate ( PI) was obtained from the protein precipitation belonging to the class of the gluteline (Ip 4.5). The conditions for the preparation of the PI were determined by both the solubility curve and simultaneous thermogravimetry-differential thermal analysis (TG-DTA): pH 11.5, absence of NaCl and whiteners and T=( 25 +/- 3) degrees C. Under these conditions a yield of 77.0 +/- 0.4%, protein content of 94.2 +/- 0.3, ashes 0.50 +/- 0.05% and thermal stability, T= 200 degrees C, were obtained. The TG-DTA curves and the PI emulsification capacity study showed the presence of hydrophobic microdomains at pH 11.5 and 3.0 suggesting a random coil protein conformation and, to pH 10.0, an open protein conformation. The capacity of emulsification (CE), in the absence of NaCl, was verified for: 1 - pH 3.0 and 8.5, using the IP extracted at pH 10.0 and 11.5, CE >= 343 +/- 5 g of emulsified oil/g of protein; 2 - pH 6.60 just for the PI obtained at pH 11.5, CE >= 140 +/- 8 g of emulsified oil/g of protein.

Ab initio study and NMR analysis of the complexion of citric acid with ion lithium

Quantum mechanics calculations at the ab initio HF/3-21G* level were carried out with Nuclear Magnetic Resonance (NMR) measurements to characterize citric acid and lithium interactions. The results indicate the formation of a tridentate organometallic compound with one lithium and one citric acid molecule and a tridentate and bidentate compound of two lithium atoms and one citric acid molecule. The results are in agreement with the experimental and theoretical data. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Phytochemical study and antiulcerogenic activity of Syngonanthus bisulcatus (Eriocaulaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermoanalytical study and characterization of native starches of Paraná pine seeds (Araucaria angustiofolia, Bert O. Ktze) and European chestnut seeds (Castanea sativa, Mill)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Spectroscopic study and local coordination of polyphosphate colloidal systems

The interaction between metaphosphate chains and the metal ions Ca2+ and Eu3+ has been studied in water by Eu3+ luminescence, infrared absorption, and P-31 NMR spectroscopy. Two main families of sites could be identified for the metal ions in the aqueous polyphosphate colloidal systems: (1) cagelike sites provided by the polyphosphate chain and (2) a family which arises following saturation of cagelike sites. Occupation of this second family leads to supramolecular interactions between polyphosphate chains and the consequent destabilization of the colloidal system. In the polyphosphate-Ca2+ system, this destabilization appears as a coacervation process. Equilibrium existing between colloidal species as a function of the compositions could be reasoned based on the spectroscopic measurements. The determination of coordination numbers and the correlation of the results with the observation of coacervates show that Eu3+ luminescence properties can be used to probe in a unique way the coacervation process.

Detection of circulating Paracoccidioides brasiliensis antigen in urine of paracoccidioidomycosis patients before and during treatment

For the diagnosis and follow-up of paracoccidioidomycosis patients undergoing therapy, we evaluated two methods (immunoblotting and competition enzyme immunoassay) for the detection of circulating antigen in urine samples. A complex pattern of reactivity was observed in the immunoblot test. Bands of 70 and 43 kDa were detected more often in urine samples from patients before treatment. The immunoblot method detected gp43 and gp70 separately or concurrently in 11 (91.7%) of 12 patients, whereas the competition enzyme immunoassay detected antigenuria in 9 (75%) of 12 patients. Both tests appeared to be highly specific (100%), considering that neither fraction detectable by immunoblotting was present in urine samples from the control group. gp43 remained present in the urine samples collected during the treatment period, with a significant decrease in reactivity in samples collected during clinical recovery and increased reactivity in samples collected during relapses. Reactivity of some bands was also detected in urine specimens from patients with 'apparent cure.' The detection of Paracoccidioides brasiliensis antigens in urine appears to be a promising method for diagnosing infection, for evaluating the efficacy of treatment, and for detecting relapse.

Argentina: how to study and act upon local innovation systems

Includes bibliography

Spectroscopic study and thermal behavior of trivalent lanthanides and yttrium(III) chelates of EDTA using TG-DSC, FTIR, and TG-DSC coupled to FTIR

Solid-state compounds of yttrium and lanthanide chelates of ethylenediaminetetraacetic acid have been synthesized. Simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), theoretical and experimental infrared spectroscopy (FTIR), elemental analysis, complexometry and TG-DSC coupled to FTIR were used to characterize and to study the thermal decomposition of these compounds. The results provided information about the composition, dehydration, thermal stability, thermal decomposition and identification of gaseous products evolved during the thermal decomposition of these compounds. The theoretical and experimental spectroscopic data suggest the possible modes of coordination of the ligand with the lanthanum and terbium metal ions. © 2013 Akadémiai Kiadó, Budapest, Hungary.