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A Biblioteca Digital da Produção Intelectual e Científica da Unicamp tem por objetivo reunir e disseminar a produção intelectual, acadêmica e cultural da universidade e preservar sua memória institucional, além de contribuir para ampliar a visibilidade da instituição e dos seus pesquisadores em âmbito nacional e internacional.

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‣ A search for anisotropy in the arrival directions of ultra high energy cosmic rays recorded at the Pierre Auger Observatory

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antici'c, T.; Aramo,
Fonte: IOP Publishing Ltd; Bristol Publicador: IOP Publishing Ltd; Bristol
Tipo: Artigo de Revista Científica
Português
Observations of cosmic rays arrival directions made with the Pierre Auger Observatory have previously provided evidence of anisotropy at the 99% CL using the correlation of ultra high energy cosmic rays (UHECRs) with objects drawn from the Veron-Cetty Veron catalog. In this paper we report on the use of three catalog independent methods to search for anisotropy. The 2pt-L, 2pt+ and 3pt methods, each giving a different measure of self-clustering in arrival directions, were tested on mock cosmic ray data sets to study the impacts of sample size and magnetic smearing on their results, accounting for both angular and energy resolutions. If the sources of UHECRs follow the same large scale structure as ordinary galaxies in the local Universe and if UHECRs are deflected no more than a few degrees, a study of mock maps suggests that these three method can efficiently respond to the resulting anisotropy with a P-value = 1.0% or smaller with data sets as few as 100 events. using data taken from January 1, 2004 to July 31, 2010 we examined the 20, 30, ... , 110 highest energy events with a corresponding minimum energy threshold of about 49.3 EeV. The minimum P-values found were 13.5% using the 2pt-L method, 1.0% using the 2pt+ method and 1.1% using the 3pt method for the highest 100 energy events. In view of the multiple (correlated) scans performed on the data set...

‣ LARGE-SCALE DISTRIBUTION OF ARRIVAL DIRECTIONS OF COSMIC RAYS DETECTED ABOVE 10(18) eV AT THE PIERRE AUGER OBSERVATORY

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Castillo, J. Alvarez; Alvarez-Muniz, J.; Batista, R. Alves; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; An
Fonte: IOP Publishing Ltd; Bristol Publicador: IOP Publishing Ltd; Bristol
Tipo: Artigo de Revista Científica
Português
A thorough search for large-scale anisotropies in the distribution of arrival directions of cosmic rays detected above 10(18) eV at the Pierre Auger Observatory is presented. This search is performed as a function of both declination and right ascension in several energy ranges above 10(18) eV, and reported in terms of dipolar and quadrupolar coefficients. Within the systematic uncertainties, no significant deviation from isotropy is revealed. Assuming that any cosmic-ray anisotropy is dominated by dipole and quadrupole moments in this energy range, upper limits on their amplitudes are derived. These upper limits allow us to test the origin of cosmic rays above 10(18) eV from stationary Galactic sources densely distributed in the Galactic disk and predominantly emitting light particles in all directions.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Measurement of the Proton-Air Cross Section at root s=57 TeV with the Pierre Auger Observatory

Abreu, P.; Aglietta, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almeda, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Anticic, T.; Aramo, C.; Arganda,
Fonte: Amer Physical Soc; College Pk Publicador: Amer Physical Soc; College Pk
Tipo: Artigo de Revista Científica
Português
We report a measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a proton-air cross section of [505 +/- 22(stat)(-36)(+28)(syst)] mb is found.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Search for signatures of magnetically-induced alignment in the arrival directions measured by the Pierre Auger Observatory

Abreu, P.; Aglietta, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Anticic, T.; Anzalone, A.; Aramo, C.; Arganda
Fonte: Elsevier; Amsterdam Publicador: Elsevier; Amsterdam
Tipo: Artigo de Revista Científica
Português
We present the results of an analysis of data recorded at the Pierre Auger Observatory in which we search for groups of directionally-aligned events (or 'multiplets') which exhibit a correlation between arrival direction and the inverse of the energy. These signatures are expected from sets of events coming from the same source after having been deflected by intervening coherent magnetic fields. The observation of several events from the same source would open the possibility to accurately reconstruct the position of the source and also measure the integral of the component of the magnetic field orthogonal to the trajectory of the cosmic rays. We describe the largest multiplets found and compute the probability that they appeared by chance from an isotropic distribution. We find no statistically significant evidence for the presence of multiplets arising from magnetic deflections in the present data. (C) 2011 Elsevier B.V. All rights reserved.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ The Lateral Trigger Probability function for the Ultra-High Energy Cosmic Ray Showers detected by the Pierre Auger Observatory (vol 35, pg 266, 2011)

Abreu, P.; Aglietta, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Anticic, T.; Anzalone, A.; Aramo, C.; Arganda
Fonte: Elsevier; Amsterdam Publicador: Elsevier; Amsterdam
Tipo: Artigo de Revista Científica
Português

‣ Directed Flow of Identified Particles in Au plus Au Collisions at root S-NN=200 GeV at RHIC

Adamczyk, L.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alakhverdyants, A. V.; Alekseev, I.; Alford, J.; Anderson, B. D.; Anson, C. D.; Arkhipkin, D.; Averichev, G. S.; Balewski, J.; Banerjee, A.; Barnovska, Z.; Beavis, D. R.; Bellwied, R.; Betancourt
Fonte: Amer Physical Soc; College Pk Publicador: Amer Physical Soc; College Pk
Tipo: Artigo de Revista Científica
Português
STAR's measurements of directed flow (v(1)) around midrapidity for pi(+/-), K-+/-, K-S(0), p, and (p) over bar in Au + Au collisions at root s(NN) = 200 GeV are presented. A negative v(1) (y) slope is observed for most of produced particles (pi(+/-), K-+/-, K-S(0), p, and (p) over bar). In 5%-30% central collisions, a sizable difference is present between the v(1)(y) slope of protons and antiprotons, with the former being consistent with zero within errors. The v(1) excitation function is presented. Comparisons to model calculations (RQMD, UrQMD, AMPT, QGSM with parton recombination, and a hydrodynamics model with a tilted source) are made. For those models which have calculations of v(1) for both pions and protons, none of them can describe v(1()y) forpions and protons simultaneously. The hydrodynamics model with a tilted source as currently implemented cannot explain the centrality dependence of the difference between the v(1)(y) slopes of protons and antiprotons.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Positron collisions with ethene

Bettega, Marcio H. F.; Sanchez, Sergio d'A.; Varella, Marcio T. do N.; Lima, Marco A. P.; Chiari, Luca; Zecca, Antonio; Trainotti, Emanuele; Brunger, Michael J.
Fonte: Amer Physical Soc; College Pk Publicador: Amer Physical Soc; College Pk
Tipo: Artigo de Revista Científica
Português
We present experimental and theoretical cross sections for positron collisions with ethene molecules. The experimental total cross sections (TCSs) were obtained with a linear transmission technique, for energies from 0.1 eV up to 70 eV. The calculations employed the Schwinger multichannel method and were performed in the static plus polarization approximation for energies up to 10 eV. Our calculated elastic cross sections indicate a Ramsauer-Townsend minimum around 2.8 eV and a virtual state, in agreement with previous calculations by da Silva et al. [Phys. Rev. Lett. 77, 1028 (1996)]. We found reasonable agreement between the calculated elastic integral cross section and the measured total cross section below the positronium formation threshold. The present results are also in quite good agreement with available theoretical and experimental data, although for the experiments this is only true for TCSs above about 7 eV.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Shape resonance spectra of lignin subunits

de Oliveira, Eliane M.; Sanchez, Sergio d'A.; Bettega, Marcio H. F.; Natalense, Alexandra P. P.; Lima, Marco A. P.; Varella, Marcio T. do N.
Fonte: Amer Physical Soc; College Pk Publicador: Amer Physical Soc; College Pk
Tipo: Artigo de Revista Científica
Português
We report integral cross sections for elastic electron scattering by the lignin subunits phenol, guaiacol, and p-coumaryl alcohol. Our calculations employed the Schwinger multichannel method with pseudopotentials and indicate three to four pi* shape resonances for each of these systems, suggesting that low-energy electrons could efficiently transfer energy into the lignin matrix. We also discuss dissociation mechanisms based on the calculated cross sections, available experimental data, virtual orbital analysis, and the knowledge on electron interactions with biomolecules. Our results point out a physical-chemical basis for electron-driven biomass delignification. The latter would be an essential step for efficient biofuel production from lignocellulosic materials.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Quantitative changes in human epithelial cancers and osteogenesis imperfecta disease detected using nonlinear multicontrast microscopy

Adur, Javier; Pelegati, Vitor B.; de Thomaz, Andre A.; D'Souza-Li, Lilia; Assuncao, Maria do Carmo; Bottcher-Luiz, Fatima; Andrade, Liliana A. L. A.; Cesar, Carlos L.
Fonte: Spie-Soc Photo-Optical Instrumentation Engineers; Bellingham Publicador: Spie-Soc Photo-Optical Instrumentation Engineers; Bellingham
Tipo: Artigo de Revista Científica
Português
We show that combined multimodal nonlinear optical (NLO) microscopies, including two-photon excitation fluorescence, second-harmonic generation (SHG), third harmonic generation, and fluorescence lifetime imaging microscopy (FLIM) can be used to detect morphological and metabolic changes associated with stroma and epithelial transformation during the progression of cancer and osteogenesis imperfecta (01) disease. NLO microscopes provide complementary information about tissue microstructure, showing distinctive patterns for different types of human breast cancer, mucinous ovarian tumors, and skin dermis of patients with OI. Using a set of scoring methods (anisotropy, correlation, uniformity, entropy, and lifetime components), we found significant differences in the content, distribution and organization of collagen fibrils in the stroma of breast and ovary as well as in the dermis of skin. We suggest that our results provide a framework for using NLO techniques as a clinical diagnostic tool for human cancer and OI. We further suggest that the SHG and FLIM metrics described could be applied to other connective or epithelial tissue disorders that are characterized by abnormal cells proliferation and collagen assembly. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.JBO.17.8.081407]; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

‣ Positron scattering from methane

Zecca, A.; Chiari, L.; Trainotti, E.; Sarkar, A.; Sanchez, S. d'A; Bettega, M. H. F.; Varella, M. T. do N.; Lima, M. A. P.; Brunger, M. J.
Fonte: Amer Physical Soc; College Pk Publicador: Amer Physical Soc; College Pk
Tipo: Artigo de Revista Científica
Português
We report on measurements of total cross sections for positron scattering from the fundamental organic molecule methane (CH(4)). The energy range of these measurements was 0.1-50 eV, whereas the energy resolution was similar to 100 meV when our Ni moderator was used and similar to 260 meV when the W moderator was employed. To assist us in interpreting these data, Schwinger multichannel calculations were performed at both static and static plus polarization levels of approximation for elastic positron scattering from 0.001 to 10 eV. These calculations are found to be in quite good qualitative agreement with our measured data, and they clearly educe the crucial role played by the target polarization in the low energy positron-CH(4) scattering dynamics.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Transverse sphericity of primary charged particles in minimum bias proton-proton collisions at root s=0.9, 2.76 and 7 TeV

Abelev, B.; Adam, J.; Adamova, D.; Adare, A. M.; Aggarwal, M. M.; Rinella, G. Aglieri; Agocs, A. G.; Agostinelli, A.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad, N.; Masoodi, A. Ahmad; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alfaro Molina
Fonte: Springer; New York Publicador: Springer; New York
Tipo: Artigo de Revista Científica
Português
Measurements of the sphericity of primary charged particles in minimum bias proton-proton collisions at root s = 0.9, 2.76 and 7 TeV with the ALICE detector at the LHC are presented. The observable is measured in the plane perpendicular to the beam direction using primary charged tracks with p(T) > 0.5 GeV/c in vertical bar eta vertical bar < 0.8. The mean sphericity as a function of the charged particle multiplicity at mid-rapidity (N-ch) is reported for events with different p(T) scales ("soft" and "hard") defined by the transverse momentum of the leading particle. In addition, the mean charged particle transverse momentum versus multiplicity is presented for the different event classes, and the sphericity distributions in bins of multiplicity are presented. The data are compared with calculations of standard Monte Carlo event generators. The transverse sphericity is found to grow with multiplicity at all collision energies, with a steeper rise at low N-ch, whereas the event generators show an opposite tendency. The combined study of the sphericity and the mean p(T) with multiplicity indicates that most of the tested event generators produce events with higher multiplicity by generating more back-to-back jets resulting in decreased sphericity (and isotropy). The PYTHIA6 generator with tune PERUGIA-2011 exhibits a noticeable improvement in describing the data...

‣ Suppression of high transverse momentum D mesons in central Pb-Pb collisions at root s(NN)=2.76 TeV

Abelev, B.; Adam, J.; Adamova, D.; Adare, A. M.; Aggarwal, M. M.; Rinella, G. Aglieri; Agocs, A. G.; Agostinelli, A.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad, N.; Masoodi, A. Ahmad; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alfaro Molina
Fonte: Springer; New York Publicador: Springer; New York
Tipo: Artigo de Revista Científica
Português
The production of the prompt charm mesons D-0, D+, D*(+), and their antiparticles, was measured with the ALICE detector in Pb-Pb collisions at the LHC, at a centre-of-mass energy root s(NN) = 2.76 TeV per nucleon-nucleon collision. The p(t)-differential production yields in the range 2 < p(t) < 16 GeV/c at central rapidity, vertical bar y vertical bar < 0.5, were used to calculate the nuclear modification factor R-AA with respect to a proton-proton reference obtained from the cross section measured at root s = 7 TeV and scaled to root s = 2.76 TeV. For the three meson species, R-AA shows a suppression by a factor 3-4, for transverse momenta larger than 5 GeV/c in the 20% most central collisions. The suppression is reduced for peripheral collisions.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Mode of Peroxisome Proliferator-Activated Receptor gamma Activation by Luteolin

Puhl, Ana C.; Bernardes, Amanda; Silveira, Rodrigo L.; Yuan, Jing; Campos, Jessica L. O.; Saidemberg, Daniel M.; Palma, Mario S.; Cvoro, Aleksandra; Ayers, Stephen D.; Webb, Paul; Reinach, Peter S.; Skaf, Munir S.; Polikarpov, Igor
Fonte: Amer Soc Pharmacology Experimental Therapeutics; Bethesda Publicador: Amer Soc Pharmacology Experimental Therapeutics; Bethesda
Tipo: Artigo de Revista Científica
Português
The peroxisome proliferator-activated receptor gamma (PPAR gamma) is a target for treatment of type II diabetes and other conditions. PPAR gamma full agonists, such as thiazolidinediones (TZDs), are effective insulin sensitizers and anti-inflammatory agents, but their use is limited by adverse side effects. Luteolin is a flavonoid with anti-inflammatory actions that binds PPAR gamma but, unlike TZDs, does not promote adipocyte differentiation. However, previous reports suggested variously that luteolin is a PPAR gamma agonist or an antagonist. We show that luteolin exhibits weak partial agonist/antagonist activity in transfections, inhibits several PPAR gamma target genes in 3T3-L1 cells (LPL, ORL1, and CEBP alpha) and PPAR gamma-dependent adipogenesis, but activates GLUT4 to a similar degree as rosiglitazone, implying gene-specific partial agonism. The crystal structure of the PPAR gamma ligand-binding domain (LBD) reveals that luteolin occupies a buried ligand-binding pocket (LBP) but binds an inactive PPAR gamma LBD conformer and occupies a space near the beta-sheet region far from the activation helix (H12), consistent with partial agonist/antagonist actions. A single myristic acid molecule simultaneously binds the LBP, suggesting that luteolin may cooperate with other ligands to bind PPAR gamma...

‣ Photophysical and photovoltaic properties of a PPV type copolymer containing alternated fluorene and thiophene units

Rodrigues, Paula C.; Grova, Isabel; Coutinho, Douglas J.; Domingues, Raquel A.; Oh, Heong Sub; Seo, Jangwon; Faria, Roberto M.; Atvars, Teresa D. Z.; Prasad, Paras N.; Akcelrud, Leni
Fonte: Springer; Dordrecht Publicador: Springer; Dordrecht
Tipo: Artigo de Revista Científica
Português
The synthesis and photophysical characterization of a PPV-type copolymer containing a fluorene derivative alternated with thiophene units is presented: poly(9,9'-dioctylfluorene-thiophene) (LAPPS29). Photophysical studies demonstrated that in the solid state only preformed ground state aggregates are responsible for exciton formation. These aggregates are formed with a wide range of size distribution. The emission from isolated segments is quenched either by resonant energy transfer, or by migration processes. Also, the main photovoltaic parameters are discussed in connection with the photophysical behavior.; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Exploring the coordination chemistry of isomerizable terpyridine derivatives for successful analyses of cis and trans isomers by travelling wave ion mobility mass spectrometry

Santos, Jonnatan J.; Toma, Sergio H.; Lalli, Priscila M.; Riccio, Maria F.; Eberlin, Marcos N.; Toma, Henrique E.; Araki, Koiti
Fonte: Royal Society Of Chemistry; Cambridge Publicador: Royal Society Of Chemistry; Cambridge
Tipo: Artigo de Revista Científica
Português
The photochemical cis-trans isomerization of the 4-{4-[2-(pyridin-4-yl)ethenyl]phenyl}-2,2': 6',2''-terpyridine ligand (vpytpy) was investigated by UV-vis, NMR and TWIM-MS. Ion mobility mass spectrometry was performed pursuing the quantification of the isomeric composition during photolysis, however an in-source trans-to-cis isomerization process was observed. In order to overcome this inherent phenomenon, the isomerization of the vpytpy species was suppressed by complexation, reacting with iron(II) ions, and forming the [Fe(vpytpy)(2)](2+) complex. The strategy of "freezing" the cis-trans isomerizable ligand at a given geometric conformation was effective, preventing further isomerization, thus allowing the distinction of each one of the isomers in the photolysed mixture. In addition, the experimental drift times were related to the calculated surface areas of the three possible cis-cis, cis-trans and trans-trans iron(II) complex isomers. The stabilization of the ligand in a given conformation also allows us to obtain the cis-cis and cis-trans complexes exhibiting the ligand in the metastable cis-conformation, as well as in the thermodynamically stable trans-conformation.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Ethnobotany of Natural Fibres - Bactris setosa (tucum) in a Traditional Rural Community

Sato Duarte, Adriana Yumi; de Queiroz, Rayana Santiago; Sanches, Regina Aparecida; Garcia, Claudia Regina; Dedini, Franco Giuseppe
Fonte: Inst Chemical Fibres; Lodz Publicador: Inst Chemical Fibres; Lodz
Tipo: Artigo de Revista Científica
Português
This work aimed to study the characteristics of the fibres of the species Bactris setosa ('tucum') used by close-knit social groups, located in Sorocaba - Sao Paulo - Brazil, in basket-making techniques, for possible applications in textile activity. Optical microscopy (NBR 13 538:1995) and Tensile Properties (ASTM D 3 822-2001) were used to assess properties such as the fibre structre, linear density, breaking force, elongation at break and breaking tenacity of each species. Bactris setosa showed a longitudinal view similar to that of sisal; an average linear density of 41.2 tex, a tenacity average of 11.96 cN/tex, closer to fiberglass, and an elongation ranging between 1.35 and 3.87%. It is important to clarify the delicacy and detail of the tests, and from this we highlight the importance of carrying out these studies, based on which science and technology must be linked with socio-environmental aspects.

‣ Cytotoxicity Tests for Nanostructured Chitosan/PEO Membranes Using the Agar Diffusion Method

Scalla Vulcani, Valcinir Aloisio; Marques Bizarria, Maria Trindade; d'Avila, Marcos Akira; Innocentini Mei, Lucia Helena; Bernal, Claudia; Perussi, Janice Rodrigues
Fonte: Univ Fed Sao Carlos, Dept Engenharia Materials; Sao Carlos Publicador: Univ Fed Sao Carlos, Dept Engenharia Materials; Sao Carlos
Tipo: Artigo de Revista Científica
Português
Electrospinning is used to produce fibers in the nanometer range by stretching a polymeric jet using electric fields of high magnitude. Chitosan is an abundant natural polymer that can be used to obtain biocompatible nanostructured membranes. The objectives of this work were to obtain nanostructured membranes based on blends of chitosan and polyoxyethylene (PEO), and evaluate their thermal and morphological properties, as well as their in vitro biocompatibility by agar diffusion cytotoxicity tests for three different cell lines. A nanostructured fibrous membrane with fiber diameters in the order of 200 nm was obtained, which presented a rough surface and thickness ranging from one to two millimeters. The results of the cytotoxicity tests evidenced that the chitosan/PEO membranes are non-toxic to the cells studied in this work. Further, the electrospinning technique was effective in obtaining nanostructured chitosan/PEO membranes, which showed biocompatibility according to in vitro preliminary tests using the cell lines.

‣ Fuzzy Connectedness Image Segmentation in Graph Cut Formulation: A Linear-Time Algorithm and a Comparative Analysis

Ciesielski, Krzysztof Chris; Udupa, Jayaram K.; Falcao, A. X.; Miranda, P. A. V.
Fonte: Springer; Dordrecht Publicador: Springer; Dordrecht
Tipo: Artigo de Revista Científica
Português
A deep theoretical analysis of the graph cut image segmentation framework presented in this paper simultaneously translates into important contributions in several directions. The most important practical contribution of this work is a full theoretical description, and implementation, of a novel powerful segmentation algorithm, GC(max). The output of GC(max) coincides with a version of a segmentation algorithm known as Iterative Relative Fuzzy Connectedness, IRFC. However, GC(max) is considerably faster than the classic IRFC algorithm, which we prove theoretically and show experimentally. Specifically, we prove that, in the worst case scenario, the GC(max) algorithm runs in linear time with respect to the variable M=|C|+|Z|, where |C| is the image scene size and |Z| is the size of the allowable range, Z, of the associated weight/affinity function. For most implementations, Z is identical to the set of allowable image intensity values, and its size can be treated as small with respect to |C|, meaning that O(M)=O(|C|). In such a situation, GC(max) runs in linear time with respect to the image size |C|. We show that the output of GC(max) constitutes a solution of a graph cut energy minimization problem, in which the energy is defined as the a"" (a) norm ayenF (P) ayen(a) of the map F (P) that associates...

‣ Common matrix metalloproteinase 2 gene haplotypes may modulate left ventricular remodelling in hypertensive patients

Lacchini, R.; Jacob-Ferreira, A. L. B.; Luizon, M. R.; Gasparini, S.; Ferreira-Sae, M. C. S.; Schreiber, R.; Nadruz, W., Jr.; Tanus-Santos, J. E.
Fonte: Nature Publishing Group; London Publicador: Nature Publishing Group; London
Tipo: Artigo de Revista Científica
Português
Matrix metalloproteinases (MMPs) are involved in cardiac remodelling. We examined whether MMP-2 genetic polymorphisms are associated with hypertension and left ventricular (LV) remodelling in hypertensive patients. We studied 160 hypertensive patients and 123 healthy controls. Echocardiography was performed in all patients and the C-1306T (rs243865) and C-735T (rs 2285053) MMP-2 polymorphisms were analysed. Haplo.stats analysis was used to evaluate whether MMP-2 haplotypes are associated with hypertension and with extremes in LV mass index (LVMI). Multiple linear regression analysis was performed to assess whether MMP-2 genotypes or haplotypes affect LVMI and other echocardiography parameters. The C-1306T 'CC' genotype was associated with reduced LVMI and LV end-diastolic diameter (EDD) (P=0.0365 and P=0.0438, respectively). The haplotype 'C, C' was associated with reduced LVMI and EDD (P=0.0278 and P=0.0322, respectively). The comparison of upper and lower extremes of the LVMI phenotype showed that the 'C, C' haplotype was more common in the lower LVMI group (P=0.0060), whereas the 'T, C' haplotype was more common in the higher quartile of LVMI (P=0.0187), and this haplotype was associated with increased risk of higher LVMI values (odds ratio=3.5121...

‣ Lipopolysaccharide treatment reduces rat platelet aggregation independent of intracellular reactive-oxygen species generation

Elisa Lopes-Pires, M.; Casarin, Andre L.; Pereira-Cunha, Fernanda G.; Lorand-Metze, Irene; Antunes, Edson; Marcondes, Sisi
Fonte: Informa Healthcare; London Publicador: Informa Healthcare; London
Tipo: Artigo de Revista Científica
Português
High production of reactive-oxygen species (ROS) by blood cells is involved in damage of the vascular endothelium and multiple organ dysfunction in sepsis. However, little is known about the intraplatelet ROS production in sepsis and its consequences on platelet reactivity. In this study, we evaluated whether the treatment of rats with lipopolysaccharide (LPS) affects platelet aggregation through intraplatelet ROS generation. Rats were injected with LPS (1 mg/kg, i.p.), and at 2 to 72 h thereafter, adenosine diphosphate (ADP) (3-10 mu M) induced platelet aggregation was evaluated. Production of ROS in platelets was measured by flow cytometry using 2',7'-dichlorofluorescein diacetate (DCFH-DA). Treatment of rats with LPS time-dependently inhibited ADP-induced platelet aggregation within 72 h. The inhibitory effect of LPS on platelet aggregation was further increased when the platelets were incubated with polyethylene glycol-superoxide dismutase (PEG-SOD; 30 U/mL), polyethylene glycol-catalase (PEG-CAT; 1000 U/mL) or the NADPH oxidase inhibitor diphenyleneiodonium (DPI; 10 mu M). The ROS production in non-stimulated platelets did not differ between control and LPS-treated rats. However, in ADP-activated platelets, generation of ROS was increased by 3.0- and 7.0-fold...