Generation of nonground-state condensates and adiabatic paradox

The problem of resonant generation of nonground-state condensates is addressed aiming at resolving the seeming paradox that arises when one resorts to the adiabatic representation. In this picture, the eigenvalues and eigenfunctions of a time-dependent Gross-Pitaevskii Hamiltonian are also functions of time. Since the level energies vary in time, no definite transition frequency can be introduced. Hence no external modulation with a fixed frequency can be made resonant. Thus, the resonant generation of adiabatic coherent modes is impossible. However, this paradox occurs only in the frame of the adiabatic picture. It is shown that no paradox exists in the properly formulated diabatic representation. The resonant generation of diabatic coherent modes is a well defined phenomenon. As an example, the equations are derived, describing the generation of diabatic coherent modes by the combined resonant modulation of the trapping potential and atomic scattering length.

Investigation by Combined Solid-State NMR and SAXS Methods of the Morphology and Domain Size in Polystyrene-b-Polyethylene Oxide-b-Polystyrene Triblock Copolymers

The microphase structure of a series of polystyrene-b-polyethylene oxide-b-polystyrene (SEOS) triblock copolymers with different compositions and molecular weights has been studied by solid-state NMR, DSC, wide and small angle X-ray scattering (WAXS and SAXS). WAXS and DSC measurements were used to detect the presence of crystalline domains of polyethyleneoxide (PEO) blocks at room temperature as a function of the copolymer chemical composition. Furthermore, DSC experiments allowed the determination of the melting temperatures of the crystalline part of the PEO blocks. SAXS measurements, performed above and below the melting temperature of the PEO blocks, revealed the formation of periodic structures, but the absence or the weakness of high order reflections peaks did not allow a clear assessment of the morphological structure of the copolymers. This information was inferred by combining the results obtained by SAXS and (1)H NMR spin diffusion experiments, which also provided an estimation of the size of the dispersed phases of the nanostructured copolymers. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48:55-64,2010

Study of absorption spectrum and dynamics evaluation of the indocyanine-green first singlet excited state

Excited state absorption and excited state dynamics of indocyanine-green (ICG) dissolved in dymethyl sulfoxide were measured using white-light continuum Z-scan (WLCZScan) and white-light continuum pump-probe (WLCPP) techniques. The excited state absorption spectrum, obtained through Z-scan measurements, revealed saturable absorption (SA) for wavelengths longer than 630 nm, while reverse saturable absorption (RSA) appeared, as indicated by a band at approximately 570 nm. Both processes were modeled by a three-energy-level diagram, from which the excited state cross-section values were determined. SA and RSA were also observed in pump-probe experiments, with a recovery time in the hundreds of picoseconds time scale due to the long lifetime of the first excited state of ICG. Such results contribute to the understanding of ICG optical properties, allowing application in photonics and medicine. Copyright (C) 2010 John Wiley & Sons, Ltd.

Floristic inventory of cerrado at Pedregulho, Sao Paulo State, Brazil

Pedregulho municipality in the far northeastern region of Sao Paulo state has fragments of cerrado vegetation thought to be floristically distinct from other cerrado remmants in the state. In this study, a floristic survey was carried out at Pedregulho, focusing on two geologically distinct regions: Furnas do Bom Jesus State Park and the Estreito district. In each region, 50x50 m plots were set up for a total sample area of 1 hectare, where 65 families and 379 angiosperm species were recorded. Collecting efforts in adjacent areas resulted in a total of 71 families and 443 species. The two study areas had low floristic similarity. Geographic species distribution was analyzed and eight patterns were defined for those species restricted to the Pedregulho region in Sao Paulo.

Leishmania spp. in Didelphis albiventris and Micoureus paraguayanus (Didelphimorphia: Didelphidae) of Brazil

Leishmaniasis is kept in nature by the participation of several animal species. This study evaluated the presence of Leishmania spp. in skin samples of free-ranging marsupials Micoureus paraguayanus (n = 95) and Didelphis albiventris (n = 191), captured in Morro do Diabo State Park and in sections of its surrounding forest, in the region of Pontal do Paranapanema, Sao Paulo State, Brazil. The samples were tested for the presence of kDNA of Leishmania spp. by polymerase chain reaction (PCR) and by real time PCR (qPCR). All samples from D. albiventris tested by PCR were negative for the presence of kDNA of Leishmania spp. However, when tested by qPCR, the positivity was 1.6%. A positivity of 7.4% by PCR and 11.6% by qPCR was observed for M. paraguayanus. Sixty-four per cent (9/14) of positive animals were limited to the same forest fragment. Presence of Leishmania (Leishmania) amazonensis and Leishmania (Viannia) braziliensis was detected in M. paraguayanus samples. While D. albiventris is the most studied marsupial species due to its urban habits, other marsupial species such as M. paraguayanus can be potential reservoirs of Leishmania spp. and should also be studied. (C) 2010 Elsevier B.V. All rights reserved.

Microstructural, structural and dielectric properties of Er(3+)-modified BaTi(0.85)Zr(0.15)O(3) ceramics

The (micro)structural and electrical properties of undoped and Er(3+)-doped BaTi(0.85)Zr(0.15)O(3) ceramics were studied in this work for both nominal Ba(2+) and Ti(4+) substitution formulations. The ceramics were produced from solid-state reaction and sintered at 1400 degrees C for 3 h. For those materials prepared following the donor-type nominal Ba(1-x)Er(x)(Ti(0.85)Zr(0.15))O(3) composition, especially, Er(3+) however showed a preferential substitution for the (Ti,Zr)(4+) lattice sites. This allowed synthesis of a finally acceptor-like, highly resistive Ba(Ti,Zr,Er)O(3-delta)-like system, with a solubility limit below but close to 3 cat.% Er(3+). The overall phase development is discussed in terms of the amphoteric nature of Er(3+), and appears to mainly or, at least, partially also involve a minimization of stress effects from the ion size mismatch between the dopant and host cations. Further results presented here include a comparative analysis of the behavior of the materials` grain size, electrical properties and nature of the ferroelectric-to-paraelectric phase transition upon variation of the formulation and Er(3+) content. (C) 2008 Elsevier Ltd. All rights reserved.

Renal ischemia in rats: Mitochondria function and laser autofluorescence

Ischemia-reperfusion injury is the major cause of organ dysfunction or even nonfunction following transplantation. It can attenuate the long-term survival of transplanted organs. To evaluate the severity of renal ischemia injury determined by histology, we applied laser(442 nm and 532 nm) induced fluorescence (LIF), mitochondria respiration, and membrane swelling to evaluate 28 Wistar rats that underwent left kidney warm ischemia for 20, 40, 60, or 80 minutes. LIF performed before ischemia (control) was repeated at 20, 40, 60, and 80 minutes thereafter. We harvested left kidney tissue samples immediately after LIF determination for histology and mitochondrial analyses: state 3 and 4 respiration, respiration control rate (RCR), and membrane swelling. The association of optic spectroscopy with histological damage showed: LIF, 442 nm (r(2) = 0.39, P < .001) and 532 nm, (r(2) = 0.18, P = .003); reflecting laser/fluorescence-induced, 442 nm (r(2) = 0.20, P = .002) and 532 nm (r(2) = 0.004, P = .67). The associations between mitochondria function and tissue damage were: state 3 respiration (r(2) = 0.43, P = .0004), state 4 respiration (r(2) = 0.03, P = 0.38), RCR (r(2) = 0.28, P = .007), and membrane swelling (r(2) = 0.02, P = .43). The intensity of fluorescence emitted by tissue excited by laser, especially at a wave length of 442 nm, was determined in real time. Mitochondrial state 3 respiration and respiratory control ratio also exhibited good correlations with the grade of ischemic tissue damage.

Spectroscopic and structural studies of bis[isopropoxy(thiocarbonyl)]sulfide, [(CH(3))(2)CHOC(S)](2)S

Structural and conformational properties of the molecule bis[isopropoxy(thiocarbonyl)]sulfide, [(CH(3))(2)CHOC(S)](2)S, have been studied by vibrational spectroscopy (IR and Raman) and quantum chemical calculations (HF and B3LYP with 6-31+G* basis sets). The crystal and molecular structure of the title compound was determined by X-ray diffraction methods. It crystallizes in the monoclinic C2/c space group with a = 8.4007(4), b = 13.5936(5), c = 10.3648(5) angstrom, beta = 106.024(4)degrees and Z = 4 molecules per unit cell. The molecules are sited on a crystallographic twofold axis passing through the sulphide atom and arranged in layers perpendicular to the b-axis. The solid state IR and Raman spectra of the compound give no sign of any other rotamer. (C) 2009 Elsevier B.V. All rights reserved.

Lipid, fatty acid, protein, amino acid and ash contents in four Brazilian red algae species

Four species of marine benthic algae (Laurencia filiformis, L. intricata, Gracilaria domingensis and G. birdiae) that belong to the phylum Rhodophyta were collected in Espirito Santo State, Brazil and investigated concerning their biochemical composition (fatty acid, total lipid, soluble proteins, amino acid and ash). The total content of lipid (% dry weight) ranged from 1.1% to 6.2%: fatty acid from 0.7% to 1.0%: soluble protein from 4.6% to 18.3%, amino acid from 6.7% to 11.3% and ash from 22.5% to 38.4%. judging from their composition, the four species of algae appear to be potential sources of dietary proteins, amino acids, lipids and essential fatty acids for humans and animals. (C) 2009 Elsevier Ltd. All rights reserved.