30 resultados para Social studies of science

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Author Cocitation Analysis (ACA) can be defined as the analysis of a group of actors, writers or researchers structurally organized in a (social and cognitive) network of a particular scientific community. The greater the number of researchers selected, the greater the amplitude and the domain boundary under consideration; the more restricted the number of researchers chosen as representative and appropriate, the less extensive the domain. From the perspective of the first axis of Tennis (2003), the selection of authors involves setting parameters on the extent of the domain, i.e., its total scope and amplitude. Thus, from the point of view of Tennis’s (2003) approach to Domain Analysis, the selection of authors for Author Cocitation Analysis is associated with the designations and boundaries of the domain, as well as to their goals (Tennis, 2003). Still, the selection of authors through the most cited authors in the literature, reflects the core elements of a domain and constitute the most specific foundation of a domain, aligning to the Degrees of Specialization characterized by Tennis (2003). It is concluded that the Author Cocitation Analysis (ACA) is a relevant procedure to the analysis of the underlying structure of a scientific knowledge domain, which meets the theories and concepts of Domain Analysis researchers, in that it allows characterizing the science, identifying, analyzing and assessing the conditions under which scientific knowledge is constructed and socialized.

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We present the structural, electronic structure and magnetic studies of Ni doped SmFeO3. The X-ray diffraction (XRD) studies confirm the single phase nature of the samples having orthorhombic Pbnm structure and the unit-cell volume is decreasing with the increase of Ni concentration. X-ray absorption spectroscopy (XAS) studies on O K. Fe L-3.2, Ni L-3.2 and Sm M-5.4 edges of SmFe1-xNixO3 (x <= 0.5) samples along with the reference compounds revealed the homo-valence state of Fe and Ni in these materials. From magnetization studies it has been observed the materials exhibit ferromagnetic and anti-ferromagnetic sub-lattices, which are strongly dependent on the thermo-magnetic state of the system. (C) 2010 Elsevier B.V. All rights reserved.

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

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

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

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BnSP-7 and BnSP-6, two Lys49-phospholipase A(2) isolated from Bothrops neuwiedi pauloensis snake venom, were co-crystallized with a-tocopherol and X-ray diffraction data were collected for both complexes (2.2 and 2.6 angstrom). A new alternative quaternary conformation for these two complexes compared with all other dimeric Lys49-PLA(2) has been observed.

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BnSP-6 (myotoxin I) is a phospholipase A2 homologue isolated from Bothrops neuwiedi pauloensis venom. Crystals of BnSP-6 were obtained which diffracted X-rays to 2.5 Angstrom resolution using a synchrotron radiation source at room temperature and belong to space group P3(1)21. The unit cell dimensions are a=b=57.7, c=131.1 Angstrom. The structure was solved by molecular replacement using the coordinates of bothropstoxin I from B. jararacussu venom. There are two molecules in the asymmetric unit.

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Venoms from Bothrops jararacussu, Bothrops asper, Bothrops atrox, Bothrops pirajai, Bothrops moojeni, Bothrops alternatus and Bothrops (Bothriopsis) bilineata were fractionated using a simplified procedure based on ion-exchange chromatography on CM-Sepharose at pH 8.0 or reverse phase HPLC. The resulting elution profiles showed important differences in the myotoxin content of these venoms. The venoms from B. alternatus, B. atrox and Bothriopsis bilineata did not contain the major myotoxin found in the other venoms. The amino acid sequence of the first 50 residues of the N-terminal region of the PLA(2)-like myotoxins showed a homology of 90-96% with other bothropic myotoxins. All of the myotoxins isolated induced rat paw edema, increased the level of plasma creatine kinase and produced myonecrosis together with polymorphonuclear cell infiltration.

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Lys49-Phospholipase A(2) (Lys49-PLA(2) - EC 3.1.1.4) homologues damage membranes by a Ca2+-independent mechanism which does not involve catalytic activity. Both MjTX-II from Bothrops moojeni and BthTX-I from Bothrops jararacussu are dimeric in solution and in the crystalline states, and a model for the Ca2+-independent membrane damaging mechanism has been suggested in which flexibility at the dimer interface region pert-nits quaternary structural transitions between open and closed membrane bound dimer conformations which results in the perturbation of membrane phospholipids and disruption of the bilayer structure [1]. With the aim of gaining insights into the structural determinants involved in protein/lipid association, we report here the crystallization and preliminary X-ray analysis of the (i) MjTX-II/SDS complex at a resolution of 2.78Angstrom, (ii) MjTX-II/STE complex at a resolution of 1.8 Angstrom and (W) BthTX-I/DMPC complex at 2.72Angstrom. These complexes were crystallized by the hanging drop vapour-diffusion technique in (i) HEPES buffer (pH 7.5) 1.8M ammonium sulfate with 2% (w/v) polyethyleneglycol 400, in (ii) 0.6-0.8 M sodium citrate as the precipitant (pH 6.0-6.5) and in (iii) sodium citrate buffer (pH 5.8) and PEG 4000 and 20% isopropanol, respectively. Single crystals of these complexes have been obtained and X-ray diffraction data have been collected at room temperature using a R-AXIS IV imaging plate system and graphite monochromated Cu Kalpha X-ray radiation generated by a Rigaku RU300 rotating anode generator for (i) and (W) and using using a Synchrotron Radiation Source (Laboratorio Nacional de Luz Sincrotron, LNLS, Campinas, Brazil) for (ii).

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In this work, GdAlO3:Pr3+ was successfully prepared by the Pechini method at lower temperatures when compared to others methods such as solid-state synthesis and sol-gel process. In accordance to the XRD data, the fully crystalline single-phase GdAlO3 could be obtained at 900 degrees C. Luminescence measurements indicate Gd -> Pr3+ energy transfer. In the emission spectra, the P-3(0) ->(3) H-4 (blue emission) and D-1(2) ->(3) H-4 (red emission) transitions of Pr3+ ions can be observed and the ratio between their intensities depends on the Pr3+ content due to the cross-relaxation phenomenon.

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Mood disorders cause many social problems, often involving family relationships. Few studies are available in the literature comparing patients with bipolar, unipolar, dysthymic, and double depressive disorders concerning these aspects. In the present study, demographic and disease data were collected using a specifically prepared questionnaire. Social adjustment was assessed using the Disability Adjustment Scale and family relationships were evaluated using the Global Assessment of Relational Functioning Scale. One hundred patients under treatment for at least 6 months were evaluated at the Psychiatric Outpatient Clinic of the Botucatu School of Medicine, UNESP. Most patients were women (82%) more than 50 (49%) years old with at least two years of follow-up, with little schooling (62% had less than 4 years), and of low socioeconomic level. Logistic regression analysis showed that a diagnosis of unipolar disorder (P = 0.003, OR = 0.075, CI = 0.014-0.403) and dysthymia (P = 0.001, OR = 0.040, CI = 0.006-0.275) as well as family relationships (P = 0.002, OR = 0.953, CI = 0914-0.992) played a significant role in social adjustment. Unipolar and dysthymic patients presented better social adjustment than bipolar and double depressive patients (P < 0.001), results that were not due to social class. These patients, treated at a teaching hospital, may represent the severest mood disorder cases. Evaluations were made knowing the diagnosis of the patients, which might also have influenced some of the results. Social disabilities among mood disorder patients are very frequent and intensive.

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The simultaneous formation of nanometer sized zinc oxide (ZnO), and acetate zinc hydroxide double salt (Zn-HDS) is described. These phases, obtained using the sol-gel synthesis route based on zinc acetate salt in alcoholic media, were identified by direct characterization of the reaction products in solution using complementary techniques: nephelometry, in situ Small-Angle X-ray Scattering (SAXS), UV-Vis spectroscopy and Extended X-ray Absorption Fine Structures (EXAFS). In particular, the hydrolytic pathway of ethanolic zinc acetate precursor solutions promoted by addition of water with the molar ratio N = [H2O]/[Zn2+] = 0.05 was investigated in this paper. The aim was to understand the formation mechanism of ZnO colloidal suspension and to reveal the factors responsible for the formation of Zn-HDS in the final precipitates. The growth mechanism of ZnO nanoparticles is based on primary particle (radius approximate to 1.5 nm) rotation inside the primary aggregate (radius < 3.5 nm) giving rise to an epitaxial attachment of particles and then subsequent coalescence. The growth of second ZnO aggregates is not associated with the Otswald ripening, and could be associated with changes in equilibrium between solute species induced by the superficial etching of Zn-HDS particles at the advanced stage of kinetic.