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  • Author or Editor: L. Carvalho x
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Seismic coda Qattenuation (Q c) in the frequency range from 6 to 20 Hz of two distinct Scoda windows (early and later portions) are compared to analyse the effects of both coda windows on crustal seismic attenuation estimates around Samambaia fault (João CâmaraNortheastern Brazil). Q cvalues associated with the later portion are systematically higher than those related to the early portion. These values follow a frequency (f) function given by Q c(f) = Q 0 f , where Q 0= 11739 and= 1.000.06. In general, Q 0estimate is less sensitive to site effects and stabler than that obtained from the early portion of S coda waves, while its corresponding frequency dependence is similar to that obtained from the early portion of S coda waves. It suggests thatparameter does not depend on coda window's location along the seismic signal. A comparative analysis of both Q 0andvalues with those found recently shows that there is no difference in using early or later portion of S coda waves in the stations located on Pre-Cambrian basement in the João Câmara area. This comparison also shows that the major variations in Q 0values were observed at seismic stations installed on sedimentary terrain. Differences in the seismic attenuation, in both sides of the Samambaia fault, were also observed in this study, and it is in agreement with the hypothesis that Samambaia fault is a kind of boundary between two seismic attenuation zones.

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Methods to determine U, Th, and other constituent elements in mineral matrices through Instrumental Neutron Activation Analysis (INAA), have been widely utilized due to their capability to extract a large quantity of information from small samples. In the present work, an experimental methodology based on INAA associated to the cluster statistics technique was used to determine the uranium concentration and its correlation with other elements present in the mineral phosphorites from the northeast region of Brazil. Data for 22 elements including rare-earth elements are presented. A good correlation between uranium and rare-earth elements is observed. For the transition metals, correlation with uranium was not noted.

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In this work, the influence of attapulgite concentration on the nucleating efficiency of isotactic polypropylene (iPP) and on the kinetics of non-isothermal crystallization were ascertained.The study was conducted by DSC. The nucleating efficiency was determined according to the procedure described by Fillon and the kinetics of non-isothermal crystallization was determined using Ozawa's method using cooling rates of 2, 5 and 10C min−1.Our results indicate that both the relative crystallinity and the crystallization temperature increase with filler content and that a maximum occurs at 2% mass/mass filler content. Both parameters decrease with increasing cooling rates. The Ozawa's exponent tended to increase with temperature and filler content.

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The role of CD25+ regulatory T cells during the course of Trypanosoma cruzi infection has been previously analyzed, and the bulk of results have shown a limited role for this T cell subpopulation. In this study, we have used an IgM, nondepleting monoclonal antibody (mAb) aiming at blocking interleukin (IL)-2 activity on CD25+ T cells. The administration of this antibody 10 days before infection increased the resistance of outbred Swiss mice to the Colombian strain of T. cruzi. Anti-CD25-treated mice had lower parasitemia and augmented numbers of effector memory T cells. In addition, these animals showed higher numbers of splenic T cells secreting IFN-γ and TNF-α, both cytokines described to be involved in the resistance to T. cruzi infection. The same treatment also increased the numbers of splenic T cells that produced homeostatic and regulatory cytokines, such as IL-2 and IL-10, and CD4+CD25+ T cells. The administration of nondepleting anti-CD25 mAb at the beginning of the chronic phase, when parasites were cleared from the blood, halted the inflammatory process in the heart, without any signs of infection reactivation. These results indicate that nondepleting anti-CD25 monoclonal antibodies may be useful to treat chronic Chagas’ disease.

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Solid-state M-2-MeO-CP compounds, where M represents bivalent Mn, Fe, Co, Ni, Cu, Zn and 2-MeO-CP is 2-methoxycinnamylidenepyruvate, were synthesized for the first time. Simultaneous thermogravimetry and differential thermal analysis, differential scanning calorimetry, X-ray powder diffractometry, infrared spectroscopy, TG-FTIR system, elemental analysis and complexometry have been used to characterize and to study the thermal behaviour of the compounds. The dehydration in all the compounds, except for iron occurs in a single step. The thermal decomposition of the anhydrous compounds occurs in two or three steps with the formation of the respective oxides, Mn3O4, Fe2O3, Co3O4, NiO, CuO and ZnO, as final residue. The results also provided information concerning the thermal behaviour and identification of the gaseous products evolved during the heating of these compounds.

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Journal of Thermal Analysis and Calorimetry
Authors: L. Lacerda, M. da Silva Carvalho Filho, I. Demiate, G. Bannach, M. Ionashiro, and E. Schnitzler

Abstract  

Corn starch, partially hydrolyzed by fungal α-amylase was investigated by using thermal analysis, microscopy and X-ray diffraction. After enzymatic treatment lower degradation onset temperatures were observed. DSC analysis showed almost similar range of gelatinization temperature, however, the enthalpies of gelatinization increased for the partially hydrolyzed starch granules. According to the X-ray diffraction analysis, stronger cereal pattern peaks were recognized after enzymatic digestion. The results suggested that the hydrolysis was more pronounced in the amorphous part of the starch granules.

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The thermal decomposition kinetics of the solid complexes Cd(S2 CNR2 )2 , where R =C2 H5 , n -C3 H7 , n -C4 H9 or iso -C4 H9 , was studied by using isothermal and non-isothermal thermogravimetry. The superimposed TG/DTG/DSC curves revealed that thermal decomposition reactions occur in the liquid phase. The kinetic model that best fitted the experimental isothermal TG data was the one-dimensional phase-boundary reaction-controlled process R1 . The thermal analysis data suggested the thermal stability sequence Cd(S2 CNBun 2 )2 >Cd(S2 CNPrn 2 )2 >Cd(S2 CNBui 2 )2 >Cd(S2 CNEt2 )2 , which accords with the sequence of stability of the apparent activation energies.

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Acta Veterinaria Hungarica
Authors: Helena Rodrigues, Maria Isabel Carvalho, Isabel Pires, Justina Prada, and Felisbina L. Queiroga

Fifty canine mammary gland tumours (CMGT) (18 benign and 32 malignant) were studied by immunohistochemical detection of active caspase-3 and Ki-67 antigens in order to determine their association with several clinicopathological parameters. The percentage of caspase-3 positive cells was significantly higher in benign tumours as compared to their malignant counterparts (P ≤ 0.001). In the group of malignant tumours there was no significant association between active caspase-3 and the clinicopathological variables considered. The percentage of Ki- 67 positive cells was significantly higher in malignant tumours compared to the benign ones (P ≤ 0.001). In the group of malignant tumours, Ki-67 expression showed a statistically significant association with tumour size (P = 0.025), histological type (P = 0.010), mitotic grade (P ≤ 0.001), nuclear grade (P = 0.025), differentiation grade (P = 0.004), histological grade of malignancy (P = 0.002), and presence of metastases in regional lymph nodes (P = 0.025). Furthermore, this study revealed a negative correlation between the percentages of active caspase-3 and Ki-67 (r = –0.39; P = 0.04). Thus, our results suggest a loss of balance between cell death and cell division in CMGT. Key words: Apoptosis, caspase-3, Ki

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