Relation between ambient humidity and ionic conductivity of poly(thionaphtheneindole): Behaviour as an amperometric humidity sensor

The electrical characteristics of oxidized poly(thionaphtheneindole) were investigated as a function of ambient relative humidity (r.h.). The current flowing through a pressed pellet of material between two massive gold electrodes plotted against voltage gives a wave-shaped curve with a halfwave potential at V = similar to 3 V. The current recorded at 4 V (plateau of the wave) is a sigmoidal function of r.h, with the inflexion point at similar to 60%. An interpretation of these findings is given, based on the influence of water on the dielectric constant of the material and on acid-base equilibrium between poly(thionaphtheneindole) and water, from which protons are produced. The behaviour of poly (thionaphtheneindole) as the active component of an amperometric humidity sensor is also reported.

Neodymium biosorption from acidic solutions in batch system

Biosorption of neodymium in batch experiments took similar to 2 h to achieve the equilibrium biosorbent-metal for all microorganisms tested. The best biosorption coefficient at a constant pH value of 1.5 was obtained using the microalgae Monoraphidium sp. (1521 mg g(-1) cell), followed by Bakers' yeast (313 mg g(-1) cell), Penicillium sp. (178 mg g(-1) cell), and activated carbon (61 mg g(-1) cell). When compared to the biosorption of other metals, these results pointed out to the application of biosorption in neodymium recovery from acidic solutions. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

Prediction and spatial variability of soil dynamic properties in sugar cane fields of São Paulo State Brazil

The objective of this work was to model and diagnose the spatial variability of soil load support capacity (SLSC) in sugar cane crop fields, as well as to evaluate the management impact on São Paulo State soil structure. The investigated variables were: pressure preconsolidation (sigma(p)), apparent cohesion () and internal friction angle (). The conclusions from the results were that the models and spatial dependence maps constitute important tools in the prediction and location of the mechanical internal strength of soils cultivated with sugar cane. They will help future soil management decisions so that soil structure sustainability will not be compromised.

Actively transcribed GAL genes can be physically linked to the nuclear pore by the SAGA chromatin modifying complex

Recent work has demonstrated that some actively transcribed genes closely associate with nuclear pore complexes (NPC) at the nuclear periphery. The Saccharomyces cerevisiae Mlp1 and Mlp2 proteins are components of the inner nuclear basket of the nuclear pore that mediate interactions with these active genes. To investigate the physical link between the NPC and active loci, we identified proteins that interact with the carboxyl-terminal globular domain of Mlp1 by tandem affinity purification coupled with mass spectrometry. This analysis led to the identification of several components of the Spt-Ada-Gcn5-acetyltransferase ( SAGA) histone acetyltransferase complex, Gcn5, Ada2, and Spt7. We utilized co-immunoprecipitation and in vitro binding assays to confirm the interaction between the Mlp proteins and SAGA components. Chromatin immunoprecipitation experiments revealed that Mlp1 and SAGA components associate with the same region of the GAL promoters. Critically, this Mlp-promoter interaction depends on the integrity of the SAGA complex. These results identify a physical association between SAGA and the NPC, and support previous results that relied upon visualization of GAL loci at the nuclear periphery by microscopy ( Cabal, G. G. Genovesio, A., Rodriguez-Navarro, S., Zimmer, C., Gadal, O., Lesne, A., Buc, H., Feuerbach- Fournier, F., Olivo-Marin, J.-C., Hurt, E. C., and Nehrbass, U. ( 2006) Nature 441, 770-773). We propose that a physical interaction between nuclear pore components and the SAGA complex can link the actively transcribed GAL genes to the nuclear pore.

Determination of acetaldehyde in fuel ethanol by high-performance liquid chromatography with electrochemical detection

The cyclic voltammetric behavior of acetaldehyde and the derivatized product with 2,4-dinitrophenylhydrazine (DNPHi) has been studied at a glassy carbon electrode. This study was used to optimize the best experimental conditions for its determination by high-performance liquid chromatographic (HPLC) separation coupled with electrochemical detection. The acetaldehyde-2,4-dinitrophenyl.hydrazone (ADNPH) was eluted and separated by a reversed-phase column, C-18, under isocratic conditions with the mobile phase containing a binary mixture of methanol/LiCl(aq) at a concentration of 1.0 x 10(-3) M (80:20 v/v) and a flow rate of 1.0 mL min(-1). The optimum condition for the electrochemical detection of ADNPH was +1.0 V vs. Ag/AgCl as a reference electrode. The proposed method was simple, rapid (analysis time 7 min) and sensitive (detection limit 3.80 mu g L-1) at a signal-to-noise ratio of 3:1. It was also highly selective and reproducible [standard deviation 8.2% +/- 0.36 (n = 5)]. The analytical curve of ADNPH was linear over the range of 3-300 mg L-1 per injection (20 mu L), and the analytical recovery was > 99%.

H-bonding in entrapped water in poly(o-methoxyaniline): Results from a differential scanning calorimetry study

Differential scanning calorimetry (DSC) was used to investigate entrapped water in poly(o-methoxyaniline) (POMA) in powder form. Two endothermic peaks were attributed to removal of water molecules that were adsorbed with distinct energies. By obtaining thermograms at various heating rates, we succeeded in applying Kissinger's approaches to estimate activation energies for the water adsorbed. The values obtained were ca. 25 and 53 kJ/mol, which correspond to H-bonding interactions, probably at the amine and imine centers of POMA, respectively. (C) 2005 Elsevier B.V. All rights reserved.

Meta-análise de parâmetros genéticos relacionados ao consumo alimentar residual e a suas características componentes em bovinos

The objective of this work was to estimate, by meta-analysis, the heritability (h(2)) and the genetic (r(g)) and phenotypic (r(f)) correlations of residual feed intake (RFI), and of its component traits in beef cattle from 19 breeds or genetic groups. Twenty-two scientific papers published from 1963 to 2011, from eight countries, totaling 52,637 cattle of ages from 28 days up to slaughter, were evaluated. The estimates of RFI, dry matter intake (DMI), average daily gain (ADG) and metabolic weight (BW0.75) were weighted by the inverse of sample variance. The variation between studies of h(2) for each trait was analyzed by weighted least squares. The effects of sex, country and breed were significant for h(2) of RFI, explaining 67% of variation between studies. For DMI, country and breed effects were significant and explained 96% of variation. Pooled estimates of h(2) were: 0.255+/-0.008, 0.278+/-0.012, 0.321+/-0.015, and 0.397+/-0.032 for RFI, DMI, ADG and BW0.75, respectively. Pooled estimates of genetic and phenotypic correlations were low between RFI and ADG and between RFI and BW0.75 (from -0.021+/-0.034 to 0.025+/-0.035), and moderate between RFI and DMI (0.636+/-0.035 and 0.698+/-0.041) and between DMI, ADG and BW0.75 (0.441+/-0.062 to 0.688+/-0.032). The trait RFI has lower heritability estimates than its components.

Intriguing evidence of translocations in Discus fish (Symphysodon, Cichlidae) and a report of the largest meiotic chromosomal chain observed in vertebrates

As part of a program to understand the genetics of Amazonian ornamental fish, classical cytogenetics was used to analyze Symphysodon aequifasciatus, S. discus and S. haraldi, popular and expensive aquarium fishes that are endemic to the Amazon basin. Mitotic analyses in Symphysodon have shown some odd patterns compared with other Neotropical cichlids. We have confirmed that Symphysodon species are characterized by chromosomal diversity and meiotic complexity despite the fact that species share the same diploid number 2n = 60. An intriguing meiotic chromosomal chain, with up to 20 elements during diplotene/diakinesis, was observed in S. aequifasciatus and S. haraldi, whereas S. discus only contains typical bivalent chromosomes. Such chromosomal chains with a high number of elements have not been observed in any other vertebrates. We showed that the meiotic chromosomal chain was not sex related. This observation is unusual and we propose that the origin of meiotic multiples in males and females is based on a series of translocations that involved heterochromatic regions after hybridization of ancestor wild Discus species. Heredity (2009) 102, 435-441; doi: 10.1038/hdy.2009.3; published online 25 February 2009

Synthesis, characterization and molecular structures of the pyridinium trans-bis(pyridine)tetrachlororuthenate(III) and pyridinium trans-(carbonyl)(pyridine)tetrachlororuthenate(III)

The pyH[trans-RuCl4(py)2](1) and pyH[trans-RuCl4(CO)(py)](2) complexes were synthesized and found to crystallize in space group P21/n, Z = 4 with a = 8.080(7), b = 22.503(7), c = 10.125(6) Å, β = 93.19(6)° for (1) and a = 7.821(1), b = 10.337(3), c = 19.763(3) Å, β = 93.07(1)° for (2). The structures were solved by Patterson and difference Fourier techniques and refined to R = 0.062 for (1) and R = 0.038 for (2). In both cases the Ru(III) ion is octahedrally coordinated to four co-planar chlorine atoms, the nitrogen of the pyridine rings or carbon from the carbon monoxide. Another protonated pyridine group, which forms the counter-cation completes the crystal structures. The UV-Vis absorption spectra show three bands: (1) 360 (ε = 1180 M-1 cm-1), 441 (ε = 3200 M-1 cm-1) and 532 nm (ε = 400 M-1 cm-1); (2) 315(ε = 1150 M-1 cm-1), 442 (ε = 3170 M-1 cm-1) and 530 nm (ε = 390 M-1 cm-1). The two higher energy bands were associated with ligand-to-metal charge transfer transitions and a third band at lower energy was assigned to a d-d transition. Low temperature EPR data confirmed the presence of the paramagnetically active Ru(III) and it is consistent with axial symmetry of the complexes. The position of the stretching CO band in complex (2) is discussed in terms of metal-CO backbonding.

Absorption and fluorescence of Er3+-doped LiYF4: Measurements and simulation

Er3+:LiYF4 single crystal has been studied by absorption and fluorescence spectroscopy in the IR-visible-UV (0-44000 cm-1) region from 4.2 K to room temperature. Polarized spectra were recorded in order to assign numerous Stark levels of electronic transitions mentioned but not attributed before in the related literature and to discuss the irreducible representations (irreps) of the 4I15/2 sublevels. A parametric hamiltonian, including free ion (Eν, α, β, γ, Tλ, ζ, Mk and Pi) and crystal field parameters (B2 0, B4 0, B4 4, B6 0 and B6 4) in an approximate D2d symmetry for the rare earth site in this scheelite type structure, was used to simulate 109 energy positions of the Er ion with a r.m.s. standard deviation of 14.6 cm-1. A comparison with previously published results for Nd3+ in the same matrix is done. © 1998 Elsevier Science S.A.

Dermatoses provocadas por animais venenosos

The venomous brazilian animals can cause accidents in human beings with great frequency. By means of this revision, the authors talk about the species and the accidentes more commons and more serious in our country. The function of the dermatologist in diagnostic, treatment and prevention of the accidents is enphatized.