Design computacional de biopolímeros derivados da cutina

Orientador: Miguel Angel San Miguel BarreraTese (doutorado) - Universidade Estadual de Campinas, Instituto de QuímicaResumo: Neste trabalho focamos em estudar o comportamento estrutural de algums polímeros de cutina, quando depositados em uma superfície de mica. Estudamos o comportamento estrutural de um ponto de vista teórico, usando a dinâmica molecular clássica em suas diferentes modalidades de campos de força. Utilizamos variados tipos de campos de força disponíveis na literatura, como: (1) campo de força atomístico (AFF), (2) campo de força coarse-grained (CGFF) e (3) campo de força reativo (RFF). Desta forma, conseguiremos estudar propriedades do sistema que estão em diferentes escalas temporais. Os monômeros de cutina usados especificamente para este trabalho foram: ácido aleurítico (9,10,16 tri-hidroxi-hexadecanoico, ALE), e ácido palmítico (hexadecanóico, PAL). Com a dinâmica molecular AFF, resolvemos o problema da densidade superficial efetiva (p), que ocorre nos monômeros de cutina quando são depositados em uma superfície de suporte. Definida a densidade efetiva (p), continuamos estudando o comportamento dos monômeros ALE e PAL, quando depositados em suas formas puras como em suas misturas 75:25 (75% ALE e 25% PAL) e 25:75 (25% ALE e 75% PAL). Além disso, estudamos o comportamento dos grupos funcionais que poderiam favorecer uma reação de esterificação nos sistemas puros de ALE e nas misturas 75:25 e 25:75. Com a dinâmica molecular CGFF, estudamos os sistemas puros de ALE e PAL. Com esse campo de força conseguimos observar propriedades que não foram observadas com a dinâmica AFF, devido à sua limitação de escala de tempo. Tivemos que desenvolver os parâmetros do campo de força CGFF para nossos sistemas, uma vez que os parâmetros CGFF não têm uma boa transferibilidade. Com a dinâmica molecular RFF, respaldamos nossos estudos sobre as reações de esterificação desenvolvidos com dinâmica AFFAbstract: In this work, we focus on studying the structural behavior of some cutin polymers when deposited on a mica surface. We study structural behavior from a theoretical point of view, using classical molecular dynamics in its different force field modalities. We use various types of force fields available in the literature, such as (1) atomistic force field (AFF), (2) coarse-grained force field (CGFF) and (3) reactive force field (RFF). In this way, we will be able to study system properties that are at different time scales. The cutin monomers used specifically for this work were: aleuritic acid (9,10,16 trihydroxyhexadecanoic acid, ALE), and palmitic acid (hexadecanoic acid, PAL). With AFF molecular dynamics, we solve the problem of effective surface density (p), which occurs in cutin monomers when they are deposited on a support surface. Having defined the effective density (p), we continue to study the behavior of monomers ALE and PAL when deposited in their pure forms as in their mixtures 75:25 (75% ALE and 25% PAL) and 25:75 (25% ALE and 75 % PAL). Besides, we study the behavior of functional groups that could favor an esterification reaction in pure ALE systems and the 75:25 and 25:75 mixtures. With CGFF molecular dynamics, we study the pure ALE and PAL systems. With this force field, we can observe properties that were not observed with the AFF dynamics, due to their time scale limitation. We had to develop the CGFF force field parameters for our systems since the CGFF parameters do not have good transferability. With RFF molecular dynamics, we support our studies on esterification reactions developed with AFF dynamicsDoutoradoFísico-QuímicaDoutor em CiênciasCAPE

The impact of invisible-spreaders on COVID-19 transmission and work resumption

The global impact of coronavirus disease 2019 (COVID-19) is unprecedented, and many control and prevention measures have been implemented to test for and trace COVID-19. However, invisible-spreaders, who are associated with nucleic acid detection and asymptomatic infections, have received insufficient attention in the current COVID-19 control efforts. In this paper, we analyze the time series infection data for Italy, Germany, Brazil, India and Sweden since the first wave outbreak to address the following issues through a series of experiments. We conclude that: 1) As of June 1, 2020, the proportion of invisible-spreaders is close to 0.4% in Sweden, 0.8% in early Italy and Germany, and 0.4% in the middle and late stages. However, in Brazil and India, the proportion still shows a gradual upward trend; 2) During the spread of this pandemic, even a slight increase in the proportion of invisible-spreaders could have large implications for the health of the community; and 3) On resuming work, the pandemic intervention measures will be relaxed, and invisible-spreaders will cause a new round of outbreaks

Participatory planning and quality assessment: contributions of a nursing management technology

Objective: to analyze the outcomes of participatory planning and quality assessment of the nursing care provided in a hospital ward using a nursing management technology. Method: Convergent care research focuses on research and practice intervention, developed in a hospital in southern Brazil from April to August 2016. Participatory planning and quality evaluation was performed using the PRAXIS® technology. Results: In the participatory planning, a survey of needs/problems was carried out by 33 professionals followed by 5 workshops, where mission, guiding principles, 4 priority problems, expected results, objectives and plans of activities were defined. For quality evaluation, two indicators were used: satisfaction and notification of adverse events. The evaluation was carried out with 101 patients and /or relatives, predominating “great or good”. Adverse events, 28 records, predominating medication errors. Conclusion: Participatory planning and quality assessment are essential to improve nursing care management and the PRAXIS® technological innovation has been a useful resource.info:eu-repo/semantics/publishedVersio

Probing the Long Gamma-Ray Burst Progenitor by Lyman-alpha Emission of Host Galaxies

Long gamma-ray bursts (GRBs) have been suggested to occur preferentially in low metallicity environment. We discuss the possibility and theoretical aspects of using Lyman alpha emission properties of long GRB host galaxies as a metallicity indicator of high redshift GRB environments, where direct metallicity measurements are not easy. We propose to use the fraction of Ly-alpha emitters (LAEs) in long GRB host galaxies as a function of UV luminosity, which can be compared with star-formation-rate weighted LAE fraction of Lyman-break galaxies as the standard in the case of no metallicity dependence. There are two important effects of metallicity dependence of long GRB rate to change the LAE fraction of host galaxies. One is the enhancement of intrinsic Ly-alpha equivalent width (EW) by stronger ionizing UV luminosity of low metallicity stellar population, and the other is extinction by interstellar dust to change the observable EW. Based on a latest theoretical model of LAEs that reproduce observations, we argue that the latter is likely to work in the opposite direction to the former, i.e., to decrease LAE fraction if GRBs preferentially occur in low-metallicity environments, because of the clumpy inter-stellar medium effect. The high LAE fraction of GRB host galaxies indicated by observations is quantitatively be explained by the LAE model if GRBs occur when Z < 0.1Z_sun, although this result is still indicative because of the limited statistics and theoretical uncertainties. This result demonstrates that the LAE statistics of GRB hosts may give us useful information in the future.Comment: 10 pages, 6 figures, accepted to ApJ, minor change

Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV

The elliptic, $v_2$, triangular, $v_3$, and quadrangular, $v_4$, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions and (anti-)protons in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV with the ALICE detector at the Large Hadron Collider. Results obtained with the event plane and four-particle cumulant methods are reported for the pseudo-rapidity range $|\eta|<0.8$ at different collision centralities and as a function of transverse momentum, $p_{\rm T}$, out to $p_{\rm T}=20$ GeV/$c$. The observed non-zero elliptic and triangular flow depends only weakly on transverse momentum for $p_{\rm T}>8$ GeV/$c$. The small $p_{\rm T}$ dependence of the difference between elliptic flow results obtained from the event plane and four-particle cumulant methods suggests a common origin of flow fluctuations up to $p_{\rm T}=8$ GeV/$c$. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least $p_{\rm T}=8$ GeV/$c$ indicating that the particle type dependence persists out to high $p_{\rm T}$.Comment: 16 pages, 5 captioned figures, authors from page 11, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186

Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}} = 2.76 TeV

The inclusive transverse momentum ($p_{\rm T}$) distributions of primary charged particles are measured in the pseudo-rapidity range $|\eta|<0.8$ as a function of event centrality in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}=2.76$ TeV with ALICE at the LHC. The data are presented in the $p_{\rm T}$ range $0.15<p_{\rm T}<50$ GeV/$c$ for nine centrality intervals from 70-80% to 0-5%. The Pb-Pb spectra are presented in terms of the nuclear modification factor $R_{\rm{AA}}$ using a pp reference spectrum measured at the same collision energy. We observe that the suppression of high-$p_{\rm T}$ particles strongly depends on event centrality. In central collisions (0-5%) the yield is most suppressed with $R_{\rm{AA}}\approx0.13$ at $p_{\rm T}=6$-7 GeV/$c$. Above $p_{\rm T}=7$ GeV/$c$, there is a significant rise in the nuclear modification factor, which reaches $R_{\rm{AA}} \approx0.4$ for $p_{\rm T}>30$ GeV/$c$. In peripheral collisions (70-80%), the suppression is weaker with $R_{\rm{AA}} \approx 0.7$ almost independently of $p_{\rm T}$. The measured nuclear modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/284

Effective Rheology of Bubbles Moving in a Capillary Tube

We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

Charge separation relative to the reaction plane in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}= 2.76 TeV

Measurements of charge dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudo-rapidity range $|\eta| < 0.8$ are presented as a function of the collision centrality, particle separation in pseudo-rapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge dependent azimuthal correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286