Preparation methods of chitosan nanoparticles: a review

El quitosano es un polisacárido natural que ha sido utilizado frecuentemente en el desarrollo de distintos materiales, debido a sus excepcionales propiedades fisicoquímicas y biológicas. Las nanopartículas de quitosano son generalmente producidas por estrategias denominadas de construcción (del inglés “bottom up”), donde el ensamblado polimérico es promovido por distintas interacciones moleculares. Sin embargo, un grupo de estrategias llamadas de deconstrucción (del inglés “top-down”) basadas en la fragmentación de estructuras macroscópicas, han generado un gran interés recientemente como alternativa para la obtención de nanomateriales. El presente trabajo hace una revisión bibliográfica de los resultados obtenidos por distintas investigaciones sobre la producción de sistemas de nanopartículas basadas en quitosano durante las últimas décadas. Las evidencias demostraron que las nanopartículas de quitosano juegan un papel preponderante en la investigación de los nanomateriales poliméricos con aplicaciones biomédicas y farmacéuticas, debido a la gran diversidad de métodos de obtención existentes que determinan las propiedades de los materiales, tales como tamaño de partícula, capacidad de incorporación y liberación de compuestos bioactivos, carga superficial, mucoadhesividad, entre otras

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Modification of χc1(3872) and ψ(2S) production in pPb collisions at √sNN = 8.16 TeV

The LHCb Collaboration measures production of the exotic hadron χc1(3872) in proton-nucleus collisions for the first time. Comparison with the charmonium state ψ(2S) suggests that the exotic χc1(3872) experiences different dynamics in the nuclear medium than conventional hadrons, and comparison with data from proton-proton collisions indicates that the presence of the nucleus may modify χc1(3872) production rates. This is the first measurement of the nuclear modification factor of an exotic hadron

Measurements of the branching fraction ratio B(ϕ → μ+μ−) / B(ϕ → e+e−) with charm meson decays

Measurements of the branching fraction ratio B(ϕ → μ+μ−) / B(ϕ → e+e−) with Ds+→π+ϕ and D+→ π+ϕ decays, denoted Rϕπs and Rϕπd, are presented. The analysis is performed using a dataset corresponding to an integrated luminosity of 5.4 fb−1 of pp collision data collected with the LHCb experiment. The branching fractions are normalised with respect to the B+ → K+J/ψ(→ e+e−) and B+ → K+J/ψ(→ μ+μ−) decay modes. The combination of the results yieldsRϕπ=1.022±0.012stat±0.048syst. The result is compatible with previous measurements of the ϕ → ℓ+ℓ− branching fractions and predictions based on the Standard Model

Amplitude analysis of the B0→K*0μ+μ− decay

An amplitude analysis of the B 0 → K * 0 μ + μ − decay is presented using a dataset corresponding to an integrated luminosity of 4.7     fb − 1 of p p collision data collected with the LHCb experiment. For the first time, the coefficients associated to short-distance physics effects, sensitive to processes beyond the standard model, are extracted directly from the data through a q 2 -unbinned amplitude analysis, where q 2 is the μ + μ − invariant mass squared. Long-distance contributions, which originate from nonfactorizable QCD processes, are systematically investigated, and the most accurate assessment to date of their impact on the physical observables is obtained. The pattern of measured corrections to the short-distance couplings is found to be consistent with previous analyses of b - to s -quark transitions, with the largest discrepancy from the standard model predictions found to be at the level of 1.8 standard deviations. The global significance of the observed differences in the decay is 1.4 standard deviations

Enhanced production of Λb0 baryons in high-multiplicity pp collisions at √s = 13 TeV

The production rate of Λ 0 b baryons relative to B 0 mesons in p p collisions at a center-of-mass energy √ s = 13     TeV is measured by the LHCb experiment. The ratio of Λ 0 b to B 0 production cross sections shows a significant dependence on both the transverse momentum and the measured charged-particle multiplicity. At low multiplicity, the ratio measured at LHCb is consistent with the value measured in e + e − collisions, and increases by a factor of ∼ 2 with increasing multiplicity. At relatively low transverse momentum, the ratio of Λ 0 b to B 0 cross sections is higher than what is measured in e + e − collisions, but converges with the e + e − ratio as the momentum increases. These results imply that the evolution of heavy b quarks into final-state hadrons is influenced by the density of the hadronic environment produced in the collision. Comparisons with several models and implications for the mechanisms enforcing quark confinement are discussed

Fraction of χc decays in prompt J/ψ production measured in pPb collisions at √sNN = 8.16 TeV

The fraction of χ c 1 and χ c 2 decays in the prompt J / ψ yield, F χ c → J / ψ = σ χ c → J / ψ / σ J / ψ , is measured by the LHCb detector in p Pb collisions at √ s NN = 8.16     TeV . The study covers the forward ( 1.5 < y ∗ < 4.0 ) and backward ( − 5.0 < y ∗ < − 2.5 ) rapidity regions, where y ∗ is the J / ψ rapidity in the nucleon-nucleon center-of-mass system. Forward and backward rapidity samples correspond to integrated luminosities of 13.6 ± 0.3 and 20.8 ± 0.5     nb − 1 , respectively. The result is presented as a function of the J / ψ transverse momentum p T , J / ψ in the range 1 < p T , J / ψ < 20     GeV / c . The F χ c → J / ψ fraction at forward rapidity is compatible with the LHCb measurement performed in p p collisions at √ s = 7     TeV , whereas the result at backward rapidity is 2.4 σ larger than in the forward region for 1 < p T , J / ψ < 3     GeV / c . The increase of F χ c → J / ψ at low p T , J / ψ at backward rapidity is compatible with the suppression of the ψ ( 2 S ) contribution to the prompt J / ψ yield. The lack of in-medium dissociation of χ c states observed in this study sets an upper limit of 180 MeV on the free energy available in these p Pb collisions to dissociate or inhibit charmonium state formation

Production and characterization of supercritical CO₂ dried chitosan nanoparticles as novel carrier device

The materials produced by the supercritical CO₂ drying have outstanding properties that allow the incorporation of molecules in their porous structure. In this context, dried chitosan nanoparticles including β-lactoglobulin were obtained. First, the nanoparticles in water suspension were produced by ionotropic gelation incorporating the protein with high loading efficiency. Later, solvent exchange and CO₂ supercritical drying procedures were performed. The physicochemical characteristics and structural properties were determined, demonstrating a stable porous structure in the dried materials and corroborating the presence of the protein after the drying. The CO₂ supercritical dried chitosan nanoparticles can be effectively resuspended in acidic aqueous medium remaining in the nanoscale with minimum effect on the loading parameters. The release of the β-lactoglobulin was highly influenced by the pH, reaching around 40% under acidic conditions in ten hours. The obtained results demonstrate the possibility to apply these chitosan materials as a controlled release material