Phase-Locked Loop design applied to frequency-modulated atomic force microscope

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

Crystal Structure Determination of Mebendazole Form A Using High-Resolution Synchrotron X-Ray Powder Diffraction Data

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

Effect of tranquilization and anesthesia on high-resolution electrocardiographic indices of dogs in the chronic chagasic myocardiopathy

Avaliou-se o efeito da tranquilização e da anestesia sobre os índices da eletrocardiografia de alta resolução (ECGAR) em cães portadores de doença-de-chagas na fase crônica indeterminada. Foram utilizados oito cães, adultos, sem raça definida, fêmeas, submetidas a seis protocolos (grupos). No grupo 1, os animais estavam sem efeito de tranquilização ou anestesia; no grupo 2, foram tranquilizados com acepromazina; no 3, foram tranquilizados com a associação acepromazina e buprenorfina; no 4, estavam sob anestesia geral inalatória com isofluorano; no 5, sob anestesia geral inalatória com sevofluorano; e no 6, sob anestesia com propofol. Os animais foram submetidos a todos os protocolos, com um período de 15 dias entre cada avaliação. Não se verificou alteração significativa na duração do complexo QRS e do LAS40 entre os grupos, e o RMS40 permaneceu sem alteração significativa. O nível de ruído foi significativamente menor nos grupos 4, 5 e 6 em relação ao grupo 1. A anestesia facilitou o registro da ECGAR sem alterar os índices eletrocardiográficos .

Role of the oriented attachment mechanism in the phase transformation of oxide nanocrystals

Bottom-up methods to obtain nanocrystals usually result in metastable phases, even in processes carried out at room temperature or under soft annealing conditions. However, stable phases, often associated with anisotropic shapes, are obtained in only a few special cases. In this paper we report on the synthesis of two well-studied oxides-titanium and zirconium oxide-in the nanometric range, by a novel route based on the decomposition of peroxide complexes of the two metals under hydrothermal soft conditions, obtaining metastable and stable phases in both cases through transformation. High-resolution transmission electron microscopy analysis reveals the existence of typical defects relating to growth by the oriented attachment mechanism in the stable crystals. The results suggest that the mechanism is associated to the phase transformation of these structures.

Quantitative Phase Analyses Through The Rietveld Method with X-Ray Powder Diffraction Data of Heat-Treated Carbamazepine Form III

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

Direct amorphous-to-cubic perovskite phase transformation for lead titanate

The phase evolution of lead titanate processed by the polymeric precursor method was investigated by thermal analysis, X-ray diffraction, and high-resolution transmission electron microscopy. The results showed that the cubic perovskite PbTiO3 (PT) phase is formed from an inorganic amorphous precursor at a temperature of 444 °C. A gradual transition from cubic to tetragonal perovskite PT was observed with the increase of calcination time at this temperature. HRTEM results showed that the cubic PT particles have a size of around 5 nm. The identification of cubic PT as an intermediate phase supports the hypothesis that the chemical homogeneity was kept at the molecular level during the synthesis process, with no cation segregation.

Including the sub-grid scale plume rise of vegetation fires in low resolution atmospheric transport models

We describe and begin to evaluate a parameterization to include the vertical transport of hot gases and particles emitted from biomass burning in low resolution atmospheric-chemistry transport models. This sub-grid transport mechanism is simulated by embedding a 1-D cloud-resolving model with appropriate lower boundary conditions in each column of the 3-D host model. Through assimilation of remote sensing fire products, we recognize which columns have fires. Using a land use dataset appropriate fire properties are selected. The host model provides the environmental conditions, allowing the plume rise to be simulated explicitly. The derived height of the plume is then used in the source emission field of the host model to determine the effective injection height, releasing the material emitted during the flaming phase at this height. Model results are compared with CO aircraft profiles from an Amazon basin field campaign and with satellite data, showing the huge impact that this mechanism has on model performance. We also show the relative role of each main vertical transport mechanisms, shallow and deep moist convection and the pyro-convection (dry or moist) induced by vegetation fires, on the distribution of biomass burning CO emissions in the troposphere.

Domain reduction using GRASP construction phase for transmission expansion planning problem

This paper proposes a new strategy to reduce the combinatorial search space of a mixed integer linear programming (MILP) problem. The construction phase of greedy randomized adaptive search procedure (GRASP-CP) is employed to reduce the domain of the integer variables of the transportation model of the transmission expansion planning (TM-TEP) problem. This problem is a MILP and very difficult to solve specially for large scale systems. The branch and bound (BB) algorithm is used to solve the problem in both full and the reduced search space. The proposed method might be useful to reduce the search space of those kinds of MILP problems that a fast heuristic algorithm is available for finding local optimal solutions. The obtained results using some real test systems show the efficiency of the proposed method. © 2012 Springer-Verlag.

Transmission network expansion planning considering phase-shifter transformers

This paper presents a novel mathematical model for the transmission network expansion planning problem. Main idea is to consider phase-shifter (PS) transformers as a new element of the transmission system expansion together with other traditional components such as transmission lines and conventional transformers. In this way, PS are added in order to redistribute active power flows in the system and, consequently, to diminish the total investment costs due to new transmission lines. Proposed mathematical model presents the structure of a mixed-integer nonlinear programming (MINLP) problem and is based on the standard DC model. In this paper, there is also applied a specialized genetic algorithm aimed at optimizing the allocation of candidate components in the network. Results obtained from computational simulations carried out with IEEE-24 bus system show an outstanding performance of the proposed methodology and model, indicating the technical viability of using these nonconventional devices during the planning process. Copyright © 2012 Celso T. Miasaki et al.

Allele frequency of hereditary equine regional dermal asthenia in American Quarter horses in Brazil determined by quantitative real-time PCR with high resolution melting analysis

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

Oil-in-water biocompatible microemulsion as a carrier for the antitumor drug compound methyl dihydrojasmonate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Resolution of isomeric multi-ruthenated porphyrins by travelling wave ion mobility mass spectrometry

The ability of travelling wave ion mobility mass spectrometry (TWIM-MS) to resolve cationic meta/para and cis/trans isomers of mono-, di-, tri- and tetra-ruthenated supramolecular porphyrins was investigated. All meta isomers were found to be more compact than the para isomers and therefore mixtures of all isomeric pairs could be properly resolved with baseline or close to baseline peak-to-peak resolution (Rp-p). Di-substituted cis/trans isomers were found, however, to present very similar drift times and could not be resolved. N-2 and CO2 were tested as the drift gas, and similar a but considerably better values of R-p and Rp-p were always observed for CO2. Copyright (C) 2012 John Wiley & Sons, Ltd.

Phase-Locked loops lock-in range in Frequency Modulated-Atomic Force Microscope nonlinear control system

Since the mid 1980s the Atomic Force Microscope is one the most powerful tools to perform surface investigation, and since 1995 Non-Contact AFM achieved true atomic resolution. The Frequency-Modulated Atomic Force Microscope (FM-AFM) operates in the dynamic mode, which means that the control system of the FM-AFM must force the micro-cantilever to oscillate with constant amplitude and frequency. However, tip-sample interaction forces cause modulations in the microcantilever motion. A Phase-Locked loop (PLL) is used to demodulate the tip-sample interaction forces from the microcantilever motion. The demodulated signal is used as the feedback signal to the control system, and to generate both topographic and dissipation images. As a consequence, a proper design of the PLL is vital to the FM-AFM performance. In this work, using bifurcation analysis, the lock-in range of the PLL is determined as a function of the frequency shift (Q) of the microcantilever and of the other design parameters, providing a technique to properly design the PLL in the FM-AFM system. (C) 2011 Elsevier B.V. All rights reserved.

Corrole isomers: intrinsic gas-phase shapes via traveling wave ion mobility mass spectrometry and dissociation chemistries via tandem mass spectrometry

Corrole and four of its isomers with subtle structural changes promoted by exchange of nitrogen and carbon atoms in the corrole ring have been studied by traveling wave ion mobility mass spectrometry and collision induced dissociation experiments. Significant differences in shapes and charge distributions for their protonated molecules were found to lead to contrasting gas phase mobilities, most particularly for corrorin, the most "confused" isomer. Accordingly, corrorin was predicted by B3LYP/6-31g(d,p) and collisional cross section calculations to display the most compact tri-dimensional structure, whereas NCC4 and corrole were found to be the most planar isomers. Better resolution between the corrole isomers was achieved using the more polarizable and massive CO2 as the drift gas. Sequential losses of HF molecules were found to dominate the dissociation chemistry of the protonated molecules of these corrole isomers, but their unique structures caused contrasting labilities towards CID, whereas NCC4 showed a peculiar and structurally diagnostic loss of NH3, allowing its prompt differentiation from the other isomers.

Kinetic resolution of alpha-bromophenylacetamides using quinine or Cinchona alkaloid salts

The kinetic resolution of racemic alpha-bromophenylacetamides 1 was achieved in the presence of benzenethiolate and Cinchona alkaloid salts as phase-transfer catalysts or benzenethiol and quinine, yielding (S)-enantioenriched alpha-sulfanylated products. The observed stereoselection was rationalized on the basis of the best fitting of 1 and the resolving agent in the ternary complexes. (C) 2012 Elsevier Ltd. All rights reserved.