212 research outputs found
Equidistribution results for geodesic flows
Using the works of Ma\~n\'e \cite{Ma} and Paternain \cite{Pat} we study the
distribution of geodesic arcs with respect to equilibrium states of the
geodesic flow on a closed manifold, equipped with a
Riemannian metric. We prove large deviations lower and upper bounds and a
contraction principle for the geodesic flow in the space of probability
measures of the unit tangent bundle. We deduce a way of approximating
equilibrium states for continuous potentials.Comment: 25 page
Ácido hialurónico e neocolagénese: a importância na harmonização orofacial – uma revisão narrativa
O ácido hialurónico desempenha um papel fundamental no funcionamento da matriz extracelular. É um seu componente fundamental, importante na morfogénese e contribui significativamente para a hidrodinâmica dos tecidos, migração e proliferação celular.
O objectivo desta revisão narrativa, é analisar o papel do ácido hialurónico em harmonização orofacial e simultaneamente compreender o seu papel na neocolagénese enquanto bioestimulador de colagénio. Procedeu-se ao levantamento de artigos nas bases de dados PubMed, Bon, Elsevier, Science Direct, considerando essencialmente os últimos 5 anos de publicação (2016 a 2021). A presença de ácido hialurónico tem sido associada ao aumento da síntese de colagénio nos tecidos mediante a ligação a receptores membranares tais como cluster de diferenciação 44 e o receptores para a motilidade mediada por hialurano. A introdução de ácido hialurónico na derme, estimula os fibroblastos a produzir colagénio tipo I. Essa estimulação está associada a um aumento localizado das forças mecânicas, indicado pelo alongamento dos fibroblastos, sendo mediada por uma regulação positiva do receptor do fator de crescimento transformante beta e do fator de crescimento do tecido conjuntivo.
O conhecimento dos princípios de bioestimulação e neocolagénese são fundamentais para melhor compreender o mecanismo de acção dos vários bioestimuladores, bem como selecionar a melhor opção em função da biologia do paciente.
Será este conhecimento dos profissionais de saúde em harmonização orofacial, que os capacitará – a mais do que dominar um conjunto de técnicas injetáveis – a entender que os princípios da harmonização orofacial integram biomedicina, biomateriais, farmacologia, engenharia e vão ciência fora, longe de encontrar fronteiras!Hyaluronic acid plays a key role in the functioning of the extracellular matrix. It is a fundamental component, important in morphogenesis and significantly contributes to tissue hydrodynamics, cell migration and proliferation.
The aim of this narrative review is to analyze the role of hyaluronic acid in orofacial harmonization and simultaneously understand its role in neocollagenesis as a collagen biostimulator.
Articles were surveyed in the PubMed, Bon, Elsevier, Science Direct databases, essentially considering the last 5 years of publication (2016 to 2021).
The presence of hyaluronic acid has been associated with increased collagen synthesis in tissues through binding to membrane receptors such as the differentiation cluster 44 and the receptor for hyaluronan-mediated motility. The introduction of hyaluronic acid in the dermis stimulates the fibroblasts to produce collagen type I. This stimulation is associated with a localized increase in mechanical forces, indicated by the elongation of the fibroblasts, being mediated by a positive regulation of the transforming growth factor beta receptor and of connective tissue growth factor.
Knowledge of the principles of biostimulation and neocollagenesis are essential to better understand the mechanism of action of the various biostimulators, as well as to select the best option depending on the patient's biology.
It will be this knowledge of health professionals in orofacial harmonization that will enable them - more than mastering a set of injectable techniques - to understand that the principles of orofacial harmonization integrate biomedicine, biomaterials, pharmacology, engineering and go beyond science, far from finding borders
Space-time laser instabilities in homogeneously broadened dense media
We investigate the space-time dynamics of a homogeneously broadened single-mode laser when local field correction (LFC) is taken into account. We demonstrate that the Maxwell-Bloch equations modified by LFC admit travelling-wave solutions, as when LFC is not taken into account. Their stability is discussed and compared to the case without LFC
Flexoelectric fluid membrane vesicles in spherical confinement
The morphology of spherically confined flexoelectric fluid membrane vesicles
in an external uniform electric field is studied numerically. Due to the
deformations induced by the confinement, the membrane becomes polarized
resulting in an interaction with the external field. The equilibrium shapes of
the vesicle without electric field can be classified in a geometrical phase
diagram as a function of scaled area and reduced volume [1,2]. When the area of
the membrane is only slightly larger than the area of the confining sphere, a
single axisymmetric invagination appears. A non-vanishing electric field
induces an additional elongation of the confined vesicle which is either
perpendicular or parallel depending on the sign of the electric field
parameter. Higher values of the surface area or the electric field parameter
can reduce the symmetry of the system leading to more complex folding. We
present the resulting shapes and show that transition lines are shifted in the
presence of an electric field. The obtained folding patterns could be of
interest for biophysical and technological applications alike.Comment: main text: 9 pages, 4 figures supplemental: 5 pages, 2 figure
Effect of Mn Doped and Mn+Sn Co-doping on the Properties of ZnO Thin Films
Mn doped and Mn/Sn co-doped ZnO thin films nanoparticles have been successfully synthesized by Spray pyrolysis technique at 300 0C. X-ray diffraction study showed that all the films have the hexagonal wurtzite structure with the preferential orientation (002) plane. The optical measurement exhibited an increase in the average transmittance from 77% for Mn doped ZnO to 84% for Mn/Sn co-doped ZnO films in the visible region. Further the optical band gap changes from 3.18 eV for undoped ZnO films to 3.27 eV for Mn/Sn co-doped ZnO films. The electrical resistivity has decreased with incorporation of Mn and Sn ions to reach the minimum value of 11 (Ω.cm) for Mn doped ZnO film
Stabilization of space–time laser instability through the finite transverse extension of pumping
We investigate the space–time dynamics of a homogeneously broadened single-mode laser when diffraction is taken into account. It is well known that such a laser displays instability when pumping reaches the second laser threshold. We show that the laser dynamics can be stabilized by pumping in a domain of finite width. The analysis of stationary solutions to the Maxwell–Bloch equations (evanescent waves, travelling waves, localized solutions) allows the stabilization mechanism to be explained
Silver nanoparticles treated activated carbon as effective sorbent for the removal of acid Red 1 dye from aqueous media: Kinetic and equilibrium studies
429-436Silver nanoparticles (AgNPLs) impregnated onto activated carbon (AC) as an effective solid adsorbent has been used for the uptake of acid red 1 (AR) from aqueous solution. In acid medium at pH ≤ 4.0, the removal of AR is found favourable than at pH ≥ 4.0. The data approve well with Fruendlich model and pseudo second-order kinetic. Adsorption capacity calculated from Langmuir is 107.5 mg/g. Thermodynamic activation parameters suggest endothermic and spontaneous process. Silver nanoparticles enhanced uptake of AR by AC. The liquid-film and intra-particle diffusion types examined the adsorption mechanism. Removal of AR from AC-AgNPLs surface carried out to illustrate the recapture of the adsorbent and adsorbate for the economic value of the remediation system. The solid phase extractor is excellent recovered for six consecutive sorption–adsorption round elucidate its rise reused
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