Showing papers by "Federal University of São Carlos published in 2008"
Daniel J. Klionsky1, Hagai Abeliovich2, Patrizia Agostinis3, Devendra K. Agrawal4 +232 more•Institutions (137)
TL;DR: A set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes are presented.
Abstract: Research in autophagy continues to accelerate,(1) and as a result many new scientists are entering the field Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms Recent reviews have described the range of assays that have been used for this purpose(2,3) There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi) Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response
2,310 citations
TL;DR: In this article, the authors analyze the use of saturation sampling as a methodological concept, frequently employed in descriptions of qualitative studies in various areas of knowledge, particularly in the field of health care, and discuss and confront the following topics: definition of sampling closure by theoretical saturation, difficulties in the acceptance and operationalization of intentional samples, adequate size of the intentional sample, the significance of valuing what is repeated or the differences contained in the sample reports, inadequate uses of expressions containing the term saturation, and finally possible metaphors for understanding the concept.
Abstract: The transparency and clarity of research reports, emphasizing the data collection stage, are considered important parameters for evaluating the scientific rigor of qualitative studies. The current paper aims to analyze the use of saturation sampling as a methodological concept, frequently employed in descriptions of qualitative studies in various areas of knowledge, particularly in the field of health care. We discuss and confront the following topics: definition of sampling closure by theoretical saturation; difficulties in the acceptance and operationalization of intentional samples (with examples), adequate size of the intentional sample, the significance of valuing what is repeated or the differences contained in the sample reports, inadequate uses of expressions containing the term saturation, and finally possible metaphors for understanding the concept.
1,146 citations
TL;DR: A review on analytical methods used to evaluate biodiesel quality was written by Knothe as discussed by the authors, and a review of the available techniques and some improvements on the analytical methods for biodiesel characterization can be found in this paper.
293 citations
TL;DR: In this article, the effect of solvent type and temperature on the formation of the α and β phases from solution cast PVDF was investigated, and it was shown that the type of phase formed depends on the crystallization rate of PVDF, which in turn is determined by the evaporation rate of the solvent.
259 citations
TL;DR: In this article, the synthesis and characterization of CuO flower-nanostructure processed in domestic hydrothermal microwave oven was presented and phase analysis was carried out using X-ray diffraction (XRD) and micro-Raman scattering (MRS).
236 citations
TL;DR: In this article, the effect of additional strengthening of hip abductor and lateral rotator muscles in a strengthening quadriceps exercise rehabilitation programme for patients with the patellofemoral pain syndrome was studied.
Abstract: Objectives: To study the effect of additional strengthening of hip abductor and lateral rotator muscles in a strengthening quadriceps exercise rehabilitation programme for patients with the patellofemoral pain syndrome.Design: Randomized controlled pilot trial.Setting: Clinical setting with home programme.Participants: Fourteen patients with patellofemoral pain syndrome.Intervention: The subjects were randomly assigned to the intervention group (strengthening of quadriceps plus strengthening of hip abductor and lateral rotator muscles) or to the control group (strengthening of quadriceps). Both groups participated in a six-week home exercise protocol.Main outcome measures: The perceived pain symptoms, isokinetic eccentric knee extensor, hip abductor and lateral rotator torques and the gluteus medius electromyographic activity were assessed before and after treatment. Parametric and non-parametric tests were used to compare the groups before and after treatment with α=0.05.Results: Only the intervention gr...
217 citations
TL;DR: The structural evolution of CaTiO3 powders heat treated in conventional furnace and adapted domestic microwave oven was analyzed by X-ray diffraction (XRD), micro-Raman scattering (MRS) spectroscopy and ultraviolet-visible (UV-vis) absorption spectrography as discussed by the authors.
188 citations
TL;DR: In this paper, the synthesis of SrMoO4 powders by co-precipitation method and processed in a microwave-hydrothermal at 413 K for 5 h.
187 citations
TL;DR: In this paper, the results of macrographic analysis and micro-hardness testing indicated that sound joints can be obtained in the parameters range of rotational speed equal to 800-1500rpm and welding speed of 150-400mm/min, while axial force and tool geometry were kept constant.
171 citations
TL;DR: The LPO levels in the blood were higher in fish from the metal-contaminated site and the chronic exposure led to significant changes in GPx, CAT, and SOD activities in all three cichlid species highlighting the importance of using a set of related biomarkers to assess the impact of water contamination.
168 citations
TL;DR: In this article, a new route was used to synthesize pure BaTiO3 (BT) nanoparticles at 140°C for 10 min under rapid reacting with stoichiometric Ba/Ti ratio.
Abstract: Hydrothermal microwave method was used as a new route to synthesize pure BaTiO3 (BT) nanoparticles at 140°C for 10 min under rapid reacting with stoichiometric Ba/Ti ratio. The crystalline products were characterized by X-ray powder diffraction (XRD) and the structure was refined by the Rietveld method from the tetragonal structure, which was supported by the Ti K-edge X-ray absorption near-edge structure (XANES). The pre-edge of Ti in the XANES spectra indicated that titanium ions are localized in a nonregular octahedron. Typical FT-Raman spectra for tetragonal BaTiO3 nanoparticles presented well-defined peaks, indicating a substantial short-range order in the system. However, a scattering peak at 810 cm−1 was attributed to the presence of lattice OH− groups, commonly found in materials obtained by hydrothermal process. Besides, the peak at 716 cm−1 can be related to eventual Ba2+ defects in the BaTiO3 lattice. BaTiO3 (BT) nanoparticles presented spherical morphology with a non-uniform distribution of pa...
TL;DR: The stabilization degree of the derivative increased with the immobilization time, an indication that a multipoint covalent attachment between enzyme and the support had really occurred, and 58-fold more stable than the soluble enzyme.
Abstract: In this work Candida antarctica lipase type B (CALB) was immobilized on agarose and chitosan. The influence of activation agents (glycidol, glutaraldehyde and epichlorohydrin) and immobilization time (5, 24 and 72 h) on hydrolytic activity, thermal and alkaline stabilities of the biocatalyst was evaluated. Protein concentration and enzymatic activity in the supernatant were determined during the immobilization process. More active derivatives were attained when the enzymatic extract was first purified through dialysis. The highest activities achieved were: for agarose-glyoxyl (with glycidol), 845 U/g of gel, after 72 h of immobilization; for chitosan-glutaraldehyde and agarose-glutaraldehyde, respectively, 1209 U/g of gel and 2716 U/g of gel, after 5 h of immobilization. Thermal stability was significantly increased, when compared to the soluble enzyme: 20-fold for agarose-glyoxyl (with glycidol)-CALB, 18-fold for chitosan-glutaraldehyde-CALB and 21-fold for agarose-glutaraldehyde. The best derivative, 58-fold more stable than the soluble enzyme, was obtained when CALB was immobilized on chitosan activated in two steps, using glycidol and glutaraldehyde, 72 h immobilization time. The stabilization degree of the derivative increased with the immobilization time, an indication that a multipoint covalent attachment between enzyme and the support had really occurred.
TL;DR: In this article, a functional method in the theory of exactly solvable models based on the Yang-Baxter algebra was proposed, and the eigenvalues of the XXZ model with non-diagonal twisted and open boundary conditions for general values of the anisotropy and boundary parameters were derived.
Book•
01 Jan 2008TL;DR: The main results from the last twenty five years in the theory of complex vector fields have been discussed in this paper, where the Baouendi-Treves approximation theorem has been proved for many function spaces.
Abstract: Detailing the main methods in the theory of involutive systems of complex vector fields this book examines the major results from the last twenty five years in the subject. One of the key tools of the subject - the Baouendi-Treves approximation theorem - is proved for many function spaces. This in turn is applied to questions in partial differential equations and several complex variables. Many basic problems such as regularity, unique continuation and boundary behaviour of the solutions are explored. The local solvability of systems of partial differential equations is studied in some detail. The book provides a solid background for others new to the field and also contains a treatment of many recent results which will be of interest to researchers in the subject.
TL;DR: These findings suggest that the solubility and conformation of these polysaccharides are related to the stability of the intrachain HO3(n)···O5(n+1) hydrogen bond, which is affected by the water exchange around the O3-HO3 hydroxyl group.
Abstract: Molecular dynamics simulations have been used to characterize the structure of single chitin and chitosan chains in aqueous solutions Chitin chains, whether isolated or in the form of a β-chitin nanoparticle, adopt the 2-fold helix with ϕ and φ values similar to its crystalline state In solution, the intramolecular hydrogen bond HO3(n)···O5(n+1) responsible for the 2-fold helical motif in these polysaccharides is stabilized by hydrogen bonds with water molecules in a well-defined orientation On the other hand, chitosan can adopt five distinct helical motifs, and its conformational equilibrium is highly dependent on pH The hydrogen bond pattern and solvation around the O3 atom of insoluble chitosan (basic pH) are nearly identical to these quantities in chitin Our findings suggest that the solubility and conformation of these polysaccharides are related to the stability of the intrachain HO3(n)···O5(n+1) hydrogen bond, which is affected by the water exchange around the O3-HO3 hydroxyl group
TL;DR: The operational regime of the bioreactor, the support material and alkalinity control were effective to select a microbial fermenting biofilm capable of producing free hydrogen and organic acids.
TL;DR: In this article, the structural evolution from structural disorder to order was monitored by X-ray diffraction and near-edge spectroscopy using high-level quantum mechanical calculations within the density functional theory framework.
TL;DR: At least at 30 degrees C, the overall reduction in the glycolytic enzyme activities of copper-exposed fish seems to reduce energy availability via glucose metabolism, thereby contributing to enhance copper toxic effects.
Abstract: We investigated the effect of copper on liver key enzymes of the anaerobic glucose metabolism (hexokinase, HK; phosphofructokinase, PFK; pyruvate kinase, PK; lactate dehydrogenase, LDH) as well as of the pentose pathway (glycose-6-phosphate dehydrogenase, G6PDH) from the fish Prochilodus lineatus. The fish were acclimated at either 20 degrees C or 30 degrees C at pH 7.0, transferred to water at pH 4.5 or 8.0, and exposed to 96 h-CL(50) copper concentrations. Copper accumulation in liver was higher in fish acclimated at 20 degrees C and maintained in water pH 8.0. Three-way analysis of variance revealed a significant effect of temperature on all enzymes, a significant effect of pH on all enzymes except for PK, and a significant effect of copper on only PFK, and LDH in pH 4.5 at 20 degrees C and, at 30 degrees C, on PFK and PK at pH 4.5 and 8.0, HK at pH 4.5 and G6PDH at pH 8.0. There were significant interactions between treatments for many enzymes. These changes suggest that the activity of enzymes in question is modified by a change in ambient water. At least at 30 degrees C, the overall reduction in the glycolytic enzyme activities of copper-exposed fish seems to reduce energy availability via glucose metabolism, thereby contributing to enhance copper toxic effects.
TL;DR: In this work the preparation of chitosan nanoparticle was investigated using methacrylic acid in different conditions and studied by particle size analyzer, zeta-potential, Fourier transform infrared spectroscopy, nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM).
TL;DR: In this article, a laser induced breakdown spectroscopy (LIBS) system has been evaluated for the determination of macronutrients (P, K, Ca, Mg) in pellets of vegetal reference materials.
01 Apr 2008
TL;DR: The association between the high energetic cost to counteract the harmful effects of this herbicide and the induction of oxidative stress suggest that low and realistic concentrations of Roundup® can have an impact on tadpoles’ performance and success, jeopardizing their survival and/or population establishment.
Abstract: Oxidative stress biomarkers, in vivo heart rate (fH), and contraction dynamics of ventricle strips of bullfrog (Lithobates catesbeiana) tadpoles were evaluated after 48 h of exposure to a sub-lethal concentration (1 ppm) of the herbicide Roundup Original® (glyphosate 41%). The activities of the antioxidant enzymes superoxide dismutase and catalase were increased in the liver and decreased in muscle, while oxidative damage to lipids increased above control values in both tissues, showing that the generation of reactive oxygen species and oxidative stress are involved in the toxicity induced by Roundup®. Additionally, tadpoles’ hyperactivity was associated with tachycardia in vivo, probably due to a stress-induced adrenergic stimulation. Ventricle strips of Roundup®-exposed tadpoles (R-group) presented a faster relaxation and also a higher cardiac pumping capacity at the in vivo contraction frequency, indicating that bullfrog tadpoles were able to perform cardiac mechanistic adjustments to face Roundup®-exposure. However, the lower maximal in vitro contraction frequency of the R-group could limit its in vivo cardiac performance, when the adrenergic-stimulation is present. The association between the high energetic cost to counteract the harmful effects of this herbicide and the induction of oxidative stress suggest that low and realistic concentrations of Roundup® can have an impact on tadpoles’ performance and success, jeopardizing their survival and/or population establishment.
TL;DR: In this article, the authors obtained information about the cobalt electrodeposition mechanism at different pH values using an electrochemistry quartz crystal microbalance (EQCM) technique as well as potentiodynamic and potentiostatic techniques.
TL;DR: The effect of combined-factors (hypoxia+copper) on the biochemical parameters and antioxidant defenses were studied in the neotropical fish Piaractus mesopotamicus as mentioned in this paper.
Abstract: The effect of combined-factors (hypoxia+copper) on the biochemical parameters and antioxidant defenses were studied in the neotropical fish Piaractus mesopotamicus. Fish were exposed for 48 h to 0.4 mg Cu(2+) L(-1) (0.4Cu), hypoxia=50 mm Hg (Hpx), and 0.4 mg Cu(2) L(-1)+hypoxia=50 mm Hg (0.4CuHpx). The exposure to 0.4Cu increased the reactive oxygen species (ROS) in the liver, accompanied by increases in superoxide dismutase (SOD) and decreases in catalase (CAT) activity, showing the influence of copper in this protection. The exposure to Hpx decreased the activity of glutathione peroxidase (GSH-Px) and CAT. Exposure to a combined-factor caused an increase in the ROS production followed by an increase in SOD and a decrease in GSH-Px and CAT. At 0.4Cu, fish presented a reduction in CAT, while in Hpx decreases in SOD, CAT and GSH-Px were observed in red muscles. Single-factors were insufficient to cause ROS production. In combined-factors, increased ROS formation and decreased SOD, CAT and GSH-Px were observed. RBC increased in all groups, but only under combined-factors was there an increase in hemoglobin. Copper plasma concentration increased in groups exposed to copper. Na(+)/K(+)-ATPase activity in gills decreased in 0.4Cu and 0.4CuHpx, and increased in Hpx. Metallothionein concentration in gills increased under combined-factors. Combined-factors caused significant disturbances in the antioxidant defenses and biochemical parameters than single-factors.
TL;DR: In this paper, perovskite-type oxides LaRu x Ni 1-x O 3 (0.0 < x < 1.0) were studied in order to find alternative catalysts, which can be more resistant against coke deactivation.
TL;DR: In this paper, high density polyethylene (HDPE) was mixed in a twin screw extruder with organophilic treated clay, Cloisite 20A, and a compatibility agent, a HDPE grafted with maleic anhydride (PEMA).
TL;DR: High-level quantum mechanical calculations in the density functional framework were used to interpret the formation of the structural defects of disorder powders in terms of band diagram and density of states.
Abstract: A strong greenish-light photoluminescence (PL) emission was measured at room temperature for disordered and ordered powders of CaMoO4 prepared by the polymeric precursor method. The structural evolution from disordered to ordered powders was accompanied by XRD, Raman spectroscopy, and TEM imagery. High-level quantum mechanical calculations in the density functional framework were used to interpret the formation of the structural defects of disorder powders in terms of band diagram and density of states. Complex cluster vacancies [MoO3 x V(O(z))] and [CaO7 x V(O(z))] (where V(O(z)) = V(O(X)), V(O(*)), V(O(**))) were suggested to be responsible to the appearance of new states shallow and deeply inserted in the band gap. These defects give rise to the PL in disordered powders. The natural PL emission of ordered CaMoO4 was attributed to an intrinsic slight distortion of the [MoO4] tetrahedral in the short range.
TL;DR: In this article, the authors study numerically the dynamics of the Rabi Hamiltonian, which describes the interaction of a single cavity mode and a two-level atom without the rotating wave approximation.
Abstract: We study numerically the dynamics of the Rabi Hamiltonian, which describes the interaction of a single cavity mode and a two-level atom without the rotating wave approximation. We analyze this system subjected to damping and dephasing reservoirs, included via the usual Lindblad superoperators in the master equation. We show that the combination of the antirotating term and the atomic dephasing leads to linear asymptotic photon generation from the vacuum. We reveal the origins of the phenomenon and estimate its importance in realistic situations.
TL;DR: Stability tests of the electrodes showed that they are suitable for use in the electrochemical treatment of phenol wastewaters.
TL;DR: It is presented new evidences that elderly and young subjects display similar capacity of heat production; however, the elderly subjects presented a lower resting temperature and slower heat dissipation.
Abstract: This study aimed at evaluating the thermographic changes associated with localized exercise in young and elderly subjects. An exercise protocol using 1 kg load was applied during 3 min to the knee flexors of 14 elderly (67 ± 5 years) and 15 young (23 ± 2 years) healthy subjects. The posterior thigh’s skin temperature of the exercised limb and contralateral limb were measured by infrared thermography on pre-exercise, immediately post-exercise, and during the 10-min period post-exercise. Difference (p < 0.01) between elderly and young subjects was observed on pre-exercise temperature. Although differences were not observed between pre-exercise and immediately post-exercise temperature in the exercised limb, thermographic profile displayed heat concentration in exercised areas for both groups. Temperature reduction was only observed for the young group on the 10-min post-exercise (p < 0.05) in the exercised limb (30.7 ± 1.7 to 30.3 ± 1.5 °C). In contrast, there was a temperature reduction post-exercise (p < 0.01) in the contralateral limb for both groups. These results present new evidences that elderly and young subjects display similar capacity of heat production; however, the elderly subjects presented a lower resting temperature and slower heat dissipation. This work contributes to improve the understanding about temperature changes in elderly subjects and may present implications to the sports and rehabilitation programs.
TL;DR: In this paper, BaMoO4 powders were prepared by the coprecipitation method and processed in a domestic microwave-hydrothermal and characterized by X-ray diffraction (XRD), Fourier transform Raman (FT-Raman) spectroscopy, ultraviolet-visible (UV-vis) absorption spectroscopic and photoluminescence (PL) measurements.