17,279 research outputs found
Caging dynamics in a granular fluid
We report an experimental investigation of the caging motion in a uniformly
heated granular fluid, for a wide range of filling fractions, . At low
the classic diffusive behavior of a fluid is observed. However, as
is increased, temporary cages develop and particles become increasingly
trapped by their neighbors. We statistically analyze particle trajectories and
observe a number of robust features typically associated with dense molecular
liquids and colloids. Even though our monodisperse and quasi-2D system is known
to not exhibit a glass transition, we still observe many of the precursors
usually associated with glassy dynamics. We speculate that this is due to a
process of structural arrest provided, in our case, by the presence of
crystallization.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let
Determinação de espécies e de raças de isolados de Verticillium oriundos de diferentes Estados do Brasil.
bitstream/CNPH-2009/33425/1/bpd_31.pd
Simulations of Time-Resolved X-Ray Diffraction in Laue Geometry
A method of computer simulation of Time-Resolved X-ray Diffraction (TRXD) in
asymmetric Laue (transmission) geometry with an arbitrary propagating strain
perpendicular to the crystal surface is presented. We present two case studies
for possible strain generation by short-pulse laser irradiation: (i) a
thermoelastic-like analytic model; (ii) a numerical model including effects of
electron-hole diffusion, Auger recombination, deformation potential and thermal
diffusion. A comparison with recent experimental results is also presented.Comment: 9 pages, 11 figure
In vivo skin hydrating efficacy of fish collagen from greenland halibut as a high-value active ingredient for cosmetic applications
The industrial processing of fish for food purposes also generates a considerable number of by-products such as viscera, bones, scales, and skin. From a value-added perspective, fish by-products can act also as raw materials, especially because of their collagen content (particularly in fish skin). Interestingly, the potential of marine collagen for cosmetic applications is enormous and, remarkably, the extraction of this protein from fish skins has been established for different species. Using this approach, we investigated the integration of marine collagen (COLRp_I) extracted from the skin of the Greenland halibut as an active ingredient in a cosmetic hydrogel formulation. In this study, extracts of marine collagen at concentrations up to 10 mg/mL showed a non-cytotoxic effect when cultured with fibroblast cells for 3 days. In addition, marine collagen extract, when incorporated into a cosmetic hydrogel formulation, met criterion A of ISO 11930:2019 regarding the efficacy of the preservative system (challenge test). In addition, the cosmetic formulations based on marine collagen at dosages of 0.1, 0.25 and 0.5% were tested in a clinical study on the skin of the forearms of 23 healthy volunteers, showing a sightly hydration effect, suggesting its potential for beauty applications. Moreover, this work illustrates that the circular economy concept applied to the fish processing industry can represent important benefits, at innovation, environmental and economic levels.The authors acknowledge the funding from the European Union Transborder Cooperation Programme Interreg España-Portugal 2014–2020 (POCTEP) under the project 0302_CVMAR_I_1_P, which supported also the cosmetic clinical study performed by INOVAPOTEK under a services acquisition contract
Marine polysaccharide multilayers: PH responsive systems for the surface modification of tissue engineering scaffolds
[Excerpt] The success of some polymeric scaffolds for Tissue Engineering is hindered by its surface chemistry, which in many cases leads to a significant foreign body response. To overcome this, the present project intend to explore a strategy of surface modification through electrostatic self-assembly, first reported in the 1990s, by the construction of multilayered systems by assembling a polycation and a polyanion in an alternate fashion. [...]info:eu-repo/semantics/publishedVersio
Influence of the porosity of starch-based fiber mesh scaffolds on the proliferation and osteogenic differentiation of bone marrow stromal cells cultured in a flow perfusion bioreactor
This study investigates the influence of the porosity of fiber mesh scaffolds obtained from a blend
of starch and poly(!-caprolactone) on the proliferation and osteogenic differentiation of marrow
stromal cells cultured under static and flow perfusion conditions. For this purpose, biodegradable
scaffolds were fabricated by a fiber bonding method into mesh structures with two different porosities–
50 and 75%. These scaffolds were then seeded with marrow stromal cells harvested from Wistar
rats and cultured in a flow perfusion bioreactor or in 6-well plates for up to 15 days. Scaffolds
of 75% porosity demonstrated significantly enhanced cell proliferation under both static and flow
perfusion culture conditions. The expression of alkaline phosphatase activity was higher in flow cultures,
but only for cells cultured onto the higher porosity scaffolds. Calcium deposition patterns
were similar for both scaffolds, showing a significant enhancement of calcium deposition on cellscaffold
constructs cultured under flow perfusion, as compared to static cultures. Calcium deposition
was higher in scaffolds of 75% porosity, but this difference was not statistically significant. Observation
by scanning electron microscopy showed the formation of pore-like structures within the
extracellular matrix deposited on the higher porosity scaffolds. Fourier transformed infrared spectroscopy
with attenuated total reflectance and thin-film X-ray diffraction analysis of the cell-scaffold
constructs after 15 days of culture in a flow perfusion bioreactor revealed the presence of a
mineralized matrix similar to bone. These findings indicate that starch-based scaffolds, in conjunction
with fluid flow bioreactor culture, minimize diffusion constraints and provide mechanical stimulation
to the marrow stromal cells, leading to enhancement of differentiation toward development
of bone-like mineralized tissue. These results also demonstrate that the scaffold structure, namely,
the porosity, influences the sequential development of osteoblastic cells and, in combination
Rotação de culturas. XXIII. Efeitos das culturas de inverno sobre o rendimento de grãos e sobre algumas caracterÃsticas agronômicas de plantas de soja, num perÃodo de nove anos.
bitstream/item/133654/1/ID12354-1988-1989sojaresultados-p88-99.pdfTrabalho apresentado na XVII Reunião de Pesquisa de Soja da Região Sul, Porto Alegre, 1989
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