Interpretation of Resistivity Piezocone Tests in a Contaminated Municipal Solid Waste Disposal Site

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

On the optimum parameters of a device for harvesting energy from running and walking

This paper investigates the feasibility of using an energy harvesting device tuned such that its natural frequency coincides with higher harmonics of the input to capture energy from walking or running human motion more efficiently. The paper starts by reviewing the concept of a linear resonant generator for a tonal frequency input and then derives an expression for the power harvested for an input with several harmonics. The amount of power harvested is estimated numerically using measured data from human subjects. Assuming that the input is periodic, the signal is reconstructed using a Fourier series before being used in the simulation. It is found that although the power output depends on the input frequency, the choice of tuning the natural frequency of the device to coincide with a particular higher harmonic is restricted by the amount of damping that is needed to maximize the amount of power harvested, as well as to comply with the size limit of the device. It is also found that it is not feasible to tune the device to match the first few harmonics when the size of the device is small, because a large amount of damping is required to limit the motion of the mass.

Determination of chromium by GFAAS in slurries of fish feces to estimate the apparent digestibility of nutrients in feed used in pisciculture

This paper presents a simple, fast and sensitive method to determine chromic oxide (used as a biological marker of fish feed) in samples of fish feces by GFAAS through the direct introduction of slurries of the samples into the spectrometer's graphite tube. The standard samples of feces and of fish feed containing 0.10-1.00 mg kg(-1) of Cr2O3 were pre-frozen for I min in liquid nitrogen and then ground a cryogenic mill for 2 min, which reduced the samples' grain size to less than 60 mu m. The standard slurries were prepared by mixing 20 mg of standard samples of fish feed or feces with I mL of a solution containing 0.05% (v/v) of Triton X-100 and 0.50% (v/v) of suprapure HNO3 directly in the spectrometer's automatic sampling glass. The final concentrations of Cr2O3 present in the standard slurries were 2, 4, 8, 16 and 20 mu g L-1. After sonicating the mixture for 20s, 10 mu L of standard slurries were injected into the graphite tube, whose internal wall was lined with a metallic palladium film that acted as a permanent chemical modifier. The limits of detection (LOD) and quantification (LOQ) calculated for 20 readings of the blank of the standard slurries (2%, m/v of feces or feed devoid of minerals) were 0.81 and 2.70 mu g L-1 of Cr2O3 for the standard feces slurries, 0.84 and 2.83 mu g L-1 of Cr2O3 for the standard feed slurries. The proposed method was applied in studies of nutrient digestibility of different fish feeds and its results proved compatible with the results obtained from samples pre-mineralized by acid digestion. (c) 2005 Elsevier B.V. All rights reserved.

Geographic variations in the composition of myotoxins from Bothrops neuwiedi snake venoms: biochemical characterization and biological activity

(1) Venom pools from Bothrops neuwiedi (Bn) and from two subspecies, namely Bothrops neuwiedi pauloensis (Bnp) and Bothrops neuwiedi urutu (Bnu), collected in the States of São Paulo (SP) and Minas Gerais (MG), Brazil, were electrophoretically examined. Basic toxins with different isoelectric points were identified in the venom collected in São Paulo (BnSP). These toxins were absent in the corresponding pools from Minas Gerais (BnMG, BnpMG and BnuMG). (2) BnSP, but not BnMG, BnpMG or BnuMG, showed two myotoxins (pI congruent to 8.6 and 8.8, respectively) which were isolated by ion-exchange chromatography on CM-Sepharose. (3) From BnMG, three myotoxic isoforms (pI congruent to 8.2 and M-r = 13600) were isolated by chromatography on CM-Sepharose followed by reversed-phase high-performance liquid chromatography. (4) the chemical and biological characterization of these toxins showed a high similarity with the Lys-49 myotoxins from other bothropic venoms. (5) Doses up to 5 LD50 (i.p.) of p-bromophenacyl bromide alkylated BnSP-7 caused a total loss of lethality in 18-22-g mice, thus indicating that the LD50 was increased by greater than 5-fold. At this dose myotoxicity was also not detectable, but the edematogenic activity on the rat paw apparently did not change. (C) 1998 Elsevier B.V. All rights reserved.

Isolation and characterization of microsatellite DNA markers for spinner dolphin (Stenella longirostris)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Molecular organization of 5S rDNA in sharks of the genus Rhizoprionodon: insights into the evolutionary dynamics of 5S rDNA in vertebrate genomes

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

Influence of physical and chemical factors during foraging and culture of the symbiont fungus in Atta sexdens rubropilosa (Hymenoptera : Formicidae)

The aim of this paper is to investigate the influence of physical and chemical factors on transport and use of substrate for Atta sexdens rubropilosa workers. Three types of rectangular fragments were used to study the physical influence factors: filter paper with paraffin, filter paper without paraffin and polyester film. To study the chemical factors, some fragments were impregnated with organic extract of orange albedo, others were soaked with soybean oil and for the remaining ones nothing was applied. The following parameters were evaluated: (i) attractiveness of substrate for transport and number of loading workers per treatment; (ii) foraged material incorporation; (iii) rejection by numbers of fragments deposited in the garbage or beside the fungus garden. All the polyester film fragments carried out to the fungus garden were subsequently rejected. We verified that chemical factors of the substrate were more quickly detected by the workers, whereas physical factors were used as a criterion in the decision-making to reject or accept the substrate collected.

Myotoxic effects of mastoparan from Polybia paulista (Hymenoptera, Epiponini) wasp venom in mice skeletal muscle

In a previous study, we showed that the Polybia paulista wasp venom causes strong myonecrosis. This study was undertaken to characterize the myotoxic potency of mastoparan (Polybia-MPII) isolated from venom (0.25 mu g/mu l) and injected in the tibial anterior (TA) muscle (i.m.) of Balb/c mice. The time course of the changes was followed at muscle degenerative (3 and 24 h) and regenerative (3, 7, and 21 days) periods (n = 6) after injection and compared to matched controls by calculation of the percentage of cross-sectional area affected and determination of creatine kinase (CK) activity (n = 10). The results showed that although NIP was strongly myotoxic, its capacity for regeneration was maintained high. Since the extent of tissue damage was not correlated with the CK serum levels, which remained very low, we raised the hypothesis that the enzyme underwent denaturation by the peptide. Evidence suggested that MP induced the death of TA fibers by necrosis and apoptosis and had the sarcolemma as its primordial target. Given its amphiphilic polycationic nature and based on the vast spectrum of functions attributed to the peptide, we suggest that MP interaction with cell membrane impaired the phosphorylation of dystrophin essential for sarcolemma mechanical stability, and disturbed Ca2+ mobilization with obvious implications on sarcoplasmic reticulum and mitochondrial functioning. (c) 2007 Elsevier Ltd. All rights reserved.

Genotoxic and mutagenic effects of fipronil on mice

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

Profiling the Proteome of the Venom from the Social Wasp Polybia paulista: A Clue to Understand the Envenoming Mechanism

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

Patterns of nucleolar activity during spermatogenesis of two triatomines, Panstrongylus megistus and P-herreri

The present work analyzed spermatogenesis in two species of triatomines (genus Panstrongylus) using silver-ion impregnation. The sex chromosomes of P. megistus and P. herreri had nucleolar organizing activity and became strongly impregnated during the phases of meiotic prophase I. Fragmentation of the nucleolus occurred in both species during the meiotic cycle. The nucleolar region could be observed up to diakinesis in meiotic prophase after which only nucleolar bodies and fragments were seen. Postmeiotic reactivation of rRNA synthesis occurred in these two species and was probably related to cell differentiation.

A micelle nucleation model for the interaction of dodecyl sulphate with Lys49-phospholipases A(2)

Bothropstoxin-I (BthTx-I) is a Lys49-PLA(2) from the venom of Bothrops jararacussu that lacks detectable catalytic activity, yet causes rapid Ca2+-independent membrane damage. With the aim of understanding the interaction between BthTx-I and amphiphilic molecules, we have studied the interaction of sodium dodecyl sulphate (SDS) with the protein. Circular dichroism and attenuated total reflection Fourier-transform infrared spectra of BthTx-I reveal changes in the alpha-helical organization of the protein at an SDS/BthTx-I molar ratio of 20-25. At SDS/BthTx-I ratios of 40-45 the alpha-helices return to a native-like conformation, although fluorescence emission anisotropy measurements of 2-amino-N-hexadecyl-benzamide (AHBA) demonstrate that the total SDS is below the critical micelle concentration when this transition occurs. These results may be interpreted as the result of SDS accumulation by the BthTx-I homodimer and the formation of a pre-micelle SDS/BthTx-I complex, which may subsequently be released from the protein surface as a free micelle. Similar changes in the alpha-helical organization of BthTx-I were observed in the presence of dipalmitoylphosphatidylcholine liposomes, suggesting that protein structure transitions coupled to organization changes of bound amphiphiles may play a role in the Ca2+-independent membrane damage by Lys49-PLA(2)s. (c) 2006 Elsevier B.V. All rights reserved.

Influence of artificial saliva in biofilm formation of Candida albicans in vitro

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

Conformal invariance of massless Duffin-Kemmer-Petiau theory in Riemannian spacetimes

We investigate the conformal invariance of massless Duffin-Kemmer-Petiau theory coupled to Riemannian spacetimes. We show that, as usual, in the minimal coupling procedure only the spin I sector of the theory - which corresponds to the electromagnetic field - is conformally invariant. We also show that the conformal invariance of the spin 0 sector can be naturally achieved by introducing a compensating term in the Lagrangian. Such a procedure - besides not modifying the spin I sector - leads to the well-known conformal coupling between the scalar curvature and the massless Klein-Gordon-Fock field. Going beyond the Riemannian spacetimes, we briefly discuss the effects of a nonvanishing torsion in the scalar case.

Determination of jet energy calibration and transverse momentum resolution in CMS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)