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Abstract  

Three nitrogenated fungicides (Bayfidan, Bayleton and Baycor) were irradiated with -rays from a60Co source with the products being analyzed by high resolution gas chromatography (HRGC). Within the dose range studied (5 to 640 kGy), all three compounds were found to be stable.

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Abstract  

Thermal degradation of granite and marble industry reject (GMIR), a red clay (RC)and their composites were studied by non-isothermal thermogravimetry (TG/DTG) in nitrogen atmosphere, differential thermal analysis (DTA) and derivative thermogravimetry(DTG) in air atmosphere. Measurements were made in the temperature range of 25–1000,25–1200 and 25–1400C. The kinetic parameters were determined by Flynn–Wall and Kissinger's methods. The results indicate the absent dominance of one mechanism of reaction, and the composites show smaller values of kinetic parameters than GMIR or RC.

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Among other objectives, forest inventories are aimed to identify ecological communities and to correlate community composition with environmental variables. The identification of different communities would require several forest inventories, each covering small sampling areas with relatively homogeneous environmental conditions. The multiple plot sampling method, traditionally used in local inventories of tropical forests, cannot assure such homogeneity, since even small sampling areas would show environmental heterogeneity influencing vegetation. In this paper we assessed the consequences of this heterogeneity for sampling by quantifying the variability of species abundance ranks for species sampled with 10 or more individuals in a set of plots covering a small sampling area. The species reference abundance ranks were obtained from a sample of 100 plots of 10 m × 10 m each randomly set in a sampling area of 6.5 ha in a tropical forest fragment (Southeastern Brazil). For each species we used resamplings (30 trials) to obtain the species abundance ranks in sub-samples, considering different sampling intensities (n = 25, 50 and 75 plots), and compared these ranks with the species reference rank (n = 100 plots). Then, we compared the species ranks in sub-samples of 50 plots (10.000 trials) with the reference rank and assessed the frequency and extent of rank displacements. Species rank was highly variable across resampling trials for the sampling intensities of n = 25 and n = 50, but decreased considerable with a sampling intensity of n = 75 plots. The mean rank variability and especially the maximum displacement raised significantly from the seventh most abundant species on, and some species occupied quite discrepant abundance ranks in up to 10% of the 10.000 resampling trials. This high internal variability of forest samples may impair the search for floristic patterns as scale lessens, say, to the meso-scale (1–100 km2). We discussed some possible ways to increase internal homogeneity of tropical forest samples with the multiple plot sampling method. Among these, objective entitation, based on an ancient phytosociological procedure, is suggested as the most appropriate for use on the hilly relieves of the Atlantic forest biome.

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Abstract  

Oxamniquine (OXA) is a schistosomicide agent that causes some adverse effects in central nervous system. Intending to improve OXA therapeutic properties, a polymeric prodrug was designed. Currently, there is an increasing interest of thermal analytical techniques in the pharmaceutical area, so differential thermal analysis (DTA) and thermogravimetry (TG) were carried out to evaluate the thermal behavior of OXA, polymethacrylic acid (PMA), [poly(methacrylic-co-oxamniquine methacrylate)acid] (PMOXA) and physical mixture (OXA+PMA). The thermoanalytical profile of the physical mixture showed characteristic events of the thermal decomposition of OXA and PMA. Distinctly, PMOXA DTA curve did not show an endothermic peak at 148.5C indicating that the drug was incorporated into the polymeric system. These results were corroborated by the IR spectroscopy and X-ray diffraction data.

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Abstract  

Solid-state compounds Ln-4Cl-BP, where Ln represents lighter trivalent lanthanides and 4Cl-BP is 4-chlorobenzylidenepyruvate, were prepared. Thermogravimetry, derivative thermogravimetry (TG and DTG), differential scanning calorimetry (DSC) and other methods of analysis were used to characterize and to study the thermal behaviour of these compounds.

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Abstract  

Instrumental neutron activation analysis (INAA) with gamma-ray spectrometry was applied to determine As, Ca, Cd, Cl, Co, Cu, Cr, Fe, Hg, K, Mg, Mn, Mo, Na, Sb, Se and Zn in the Brazilian agroindustrial by-products. These materials are widely used in ruminant feeding. The results obtained were compared with requirement and maximum tolerable concentrations. The general conclusions from the data obtained were: (1) many by-products presented concentrations of some essential elements lower than the requirement concentrations, while in some concentrations of Cr, Fe, Mg and Se exceeded by a little the maximum tolerable concentrations, (2) the elements As, Cd, Hg and Sb, generally considered toxic, showed concentrations lower than maximum tolerable values.

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Abstract  

Solid-state compounds of general formula LnL32H2O, where Ln is heavier trivalent lanthanides and yttrium, L is 4-chlorobenzylidenepyruvate have been synthetised. On heating these compounds decompose in steps. They lose the hydration water in the first step and the thermal decomposition of the anhydrous compounds occurs with the formation of oxochloride (Eu, Gd); mixture of oxide and oxochloride that decrease with increasing of atomic number of metal (Tb-Tm); or oxide (Yb, Lu, Y) as final residue, up to 900C. The dehydration enthalpies found for terbium, holmium, ytterbium and yttrium compounds were: 34.93, 42.40, 57.39 and 62.24 kJ mol-1, respectively.

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Blood constituents labeled with technetium-99m ( 99m Tc) have been used in nuclear medicine procedures and drugs are capable to interfere on this labeling. Lantana camara (lantana) has medicinal properties and it has been used in folk medicine. The aim is to verify the effect of a lantana extract on the labeling of blood constituents with 99m Tc. Blood of rats was incubated with extract, stannous chloride and 99m Tc, as sodium pertechnetate. Plasma (P) and blood cells (BC) were isolated, also precipitated with trichloroacetic acid and soluble (SF) and insoluble fractions (IF) were separated. The % of radioactivity (%ATI) in these samples was calculated. Samples of labeled BC were washed and the %ATI maintained (%ATI-M) in the BC was determined. The results showed that lantana extract decreased significantly (p<0.05) in the IF-P from 70.24±2.59 to 11.95±3.07. This effect was not observed in the BC and IF-BC. The BC-%ATI-M was significantly (p<0.05) decreased in all concentrations tested when the BC was washed. This fact was not observed in the control. Substances present on the extract should have redoxi action decreasing the concentration of the stannous ion and this condition could justify the effect on the IF-P. The results about the BC-%ATI-M should indicate a possible effect on the transport of ions through the erythrocyte membrane.

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Acetylsalicylic acid is the most widely used drug as antipyretic, analgesic, anti-inflammatory agent and for secondary prevention of thrombotic phenomena in the heart, brain and peripheral circulation. Drugs can modify the labeling of blood constituents with technetium-99m ( 99m Tc). This work has evaluated the effect of in vivo treatment with acetylsalicylic acid on the in vitro labeling of the blood constituents with 99m Tc. Wistar rats were treated with different doses (1.5, 3.0 and 6.0 mg/kg) of acetylsalicylic acid during 1 hour. At higher dose used (6.0 mg/kg) animals were treated during different period of time (0.25, 1.0 and 4.0 hours). Animals treated with physiologic saline solution were used as control. After the labeled process; plasma (P), blood cells (BC), insoluble (IF-P, IF-BC) and soluble (SF-P, SF-BC) fractions were separated. Afterwards, the percentage of radioactivity (%ATI) in each fraction was calculated. The treatment during 1 hour with acetylsalicylic acid at higher dose has significantly (p<0.05) modified the fixation of 99m Tc on blood cells. Considering the results, we suggest that acetylsalicylic acid used at therapeutic doses may interfere with the nuclear medicine procedures related to these blood constituents.

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Abstract  

A formulation of nifedipine tablets was prepared in the present research. The tablets were conditioned in amber-colored glass containers and placed in a climatized room at 40°C and relative humidity of 75% for 180 days. Differential scanning calorimetry (DSC) and thermogravimetry (TG) were used in order to evaluate the thermal properties of nifedipine, the excipients and two well-known nifedipine degradation products. The results demonstrated that there is no evidence on the interaction between nifedipine and excipients, or degradation products.

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