Fabrication of phytic acid sensor based on mixed phytase-lipid Langmuir-Blodgett films

This paper reports the surface activity of phytase at the air-water interface, its interaction with lipid monolayers, and the construction of a new phytic acid biosensor on the basis of the Langmuir-Blodgett (LB) technique. Phytase was inserted in the subphase solution of dipalmitoylphosphatidylglycerol (DPPG) Langmuir monolayers, and its incorporation to the air-water interface was monitored with surface pressure measurements. Phytase was able to incorporate into DPPG monolayers even at high surface pressures, ca. 30 mN/m, under controlled ionic strength, pH, and temperature. Mixed Langmuir monolayers of phytase and DPPG were characterized by surface pressure-area and surface potential-area isotherms, and the presence of the enzyme provided an expansion in the monolayers ( when compared to the pure lipid at the interface). The enzyme incorporation also led to significant changes in the equilibrium surface compressibility (in-plane elasticity), especially in liquid-expanded and liquid-condensed regions. The dynamic surface elasticity for phytase-containing interfaces was investigated using harmonic oscillation and axisymmetric drop shape analysis. The insertion of the enzyme at DPPG monolayers caused an increase in the dynamic surface elasticity at 30 mN m(-1), indicating a strong interaction between the enzyme and lipid molecules at a high-surface packing. Langmuir-Blodgett (LB) films containing 35 layers of mixed phytase-DPPG were characterized by ultraviolet-visible and fluorescence spectroscopy and crystal quartz microbalance nanogravimetry. The ability in detecting phytic acid was studied with voltammetric measurements.

Air-drying of fresh and osmotically pre-treated pineapple slices: Fixed air temperature versus fixed slice temperature drying kinetics

In this investigation, the air drying characteristics of fresh and osmotically pre-treated pineapple slices in a tray dryer were studied under different operating conditions. The air velocity varied from 1.5 to 2.5 m/s and the air temperature from 40 to 70 degreesC. The analytical solution of the second Fick's law for an infinite slab was used to calculate effective diffusion coefficients and their temperature dependence could be well represented by an Arrhenius-type equation. Comparison of the results showed that the diffusion coefficients were lower for the pre-treated fruit. By means of automatic control, it was possible to obtain drying curves under conditions of constant product temperature, which showed to be an alternative to reduce the drying time of pineapple slices.

Optical and electrical diagnostics of a spark-plug discharge in air

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

Thermal behaviour of fumaric acid, sodium fumarate and its compounds with light trivalent lanthanides in air atmosphere

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

Analysis of various conditions in order to measure electromyography of isometric contractions in water and on air

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A Method for Determination of Ammonia in Air using Oxalic Acid-Impregnated Cellulose Filters and Fluorimetric Detection

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ventilation of the giant nests of Atta leaf-cutting ants: does underground circulating air enter the fungus chambers?

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

Evaluation of uranium incorporation from contaminated areas using teeth as bioindicators - a case study

The Southwest region of the Bahia state in Brazil hosts the largest uranium reserve of the country (100 kton in uranium, only), plus the cities of Caetite, Lagoa Real and Igapora. In this work, aim was at the investigation of uranium burdens on residents of these cities by using teeth as bioindicators, as a contribution for possible radiation protection measures. Thus, a total of 41 human teeth were collected, plus 50 from an allegedly uranium free area (the control region). Concentrations of uranium in teeth from residents of 5- to 87-y old were determined by means of a high-resolution inductively coupled plasma mass spectrometer (ICP-MS). The highest uranium concentration in teeth was measured from samples belonging to residents of Caetite (median equal to 16 ppb). Assuming that the uranium concentrations in teeth and bones are similar within 10-20% (for children and young adults), it concluded that uranium body levels in residents of Caetite are at least one order of magnitude higher than the worldwide average. This finding led to conclude that daily ingestion of uranium, from food and water, is equally high.

The lipid composition of a cell membrane modulates the interaction of an antiparasitic peptide at the air-water interface

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

Influence of Ga incorporation on photoinduced phenomena in Ge-S based glasses

To study the influence of Ga addition on photoinduced effect, GaGeS glasses with constant atomic ratio S/Ge = 2.6 have been prepared. Using Raman spectroscopy, we have reported the effect of Ga on the structural behavior of these glasses. An increase of the glass transition temperature T(g), the linear refractive index and the density have been observed with increasing gallium content. The photoinduced phenomena have been examined through the influence of time exposure and power density, when exposed to above light bandgap (3.53 eV). The correlation between photoinduced phenomena and Ga content in such glasses are shown hereby. (C) 2009 Elsevier B.V. All rights reserved.

INCORPORATION of NEEM LEAVES INTO SOIL TO CONTROL BACTERIAL WILT of TOMATO

The objective of this study was to evaluate the effect of incorporation of neem (Azadirachta indica) leaves into the soil for controlling bacterial wilt of tomato caused by Ralstonia solanacearum. The experiment was conducted in a greenhouse of the State University of Maranhao (Brazil). Dry and fresh neem leaves were incorporated in the soil in different amounts (0, 20, 40, 60, 80 and 100 g) and kept in it for different periods of time (0, 15, 30, 45 and 60 days). After each of these periods, seedlings inoculated with R. solanacearum were transplanted in the amended soil. Results showed positive effects in the disease control by incorporating neem leaves, with a reduction of wilting symptoms up to 100% with dry leaves and 78% with fresh leaves.

Influence of pH on the incorporation and growth of Pb2CrO5 crystallites in silica matrix

Pb2CrO5 nanoparticles were embedded in an amorphous SiO2 matrix by the sol-gel process. The pH and heat treatment effects were evaluated in terms of structural, microstructural and optical properties from Pb2CrO5/SiO2 compounds. X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), energy dispersive spectroscopy (EDS), and diffuse reflectance techniques were employed. Kubelka-Munk theory was used to calculate diffuse reflectance spectra that were compared to the experimental results. Finally, colorimetric coordinates of the Pb2CrO5/SiO2 compounds were shown and discussed. In general, an acid pH initially dissolves Pb2CrO5 nanoparticles and following heat treatment at 600 A degrees C crystallized into PbCrO4 composition with grain size around 6 nm in SiO2 matrix. No Pb2CrO5 solubilization was observed for basic pH. These nanoparticles were incorporated in silica matrix showing a variety of color ranging from yellow to orange.

Ligand Exchange Inducing Efficient Incorporation of CisPt Derivatives into Ureasil-PPO Hybrid and Their Interactions with the Multifunctional Hybrid Network

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Air-sea interaction studies at the station occupied by R/V Sirius

The transfer formulas are used to compute hourly values of sensible and latent heat exchanges for the period July 29 to July 31, 1974. Also, values of eddy shearing stress at the sea surface, Bowen's ratio and dissipation of kinetic energy are computed. The data used cover part of the GATE period for station 20 occupied by the Brazilian Naval Ship R/V Sirius in the Equatorial Atlantic (0730 N 4000 W). The variations in the computed values are studied in relation to rainfall and the synoptic situation. © 1980 D. Reidel Publishing Co.

Effect of air temperature and humidity on ingestive behaviour of sheep

Thirty-two Polwarth ewes, of ages up to 1 year, were observed in a climatic chamber (24 to 45° C) for eight periods of 5 h each. The observations were made through a window in the chamber wall. All animals were observed four times, then shorn and observed four times again. The animals were given weighed quantities of water and feed consisting of commercial concentrate plus Rhodes grass (Chloris gayana) hay. The water and feed remaining after 5 h of observation were weighed. The following traits were analysed: time eating hay (TEH), time eating concentrate (TEC), time drinking water (TDW), weight of hay eaten (WHE), weight of concentrate eaten (WCE), volume of ingested water (VIW), ruminating time standing up (RTS), ruminating time lying down (RTL), idling time standing up (ITS), and idling time lying down (ITL). Shearing had a significant effect for all traits except ITS. Shearing resulted in higher values for all traits except for ITS and ITL. Ingestion of hay (TEH and WHE) decreased with increased air temperature and humidity, while the ingestion of concentrate (TEC) and WHE) and water (TDW and VIW) increased. Rumination decreased with increased air temperature and humidity, and was higher in shorn than in unshorn sheep. © 1992 International Society of Biometeorology.