18 research outputs found
Use of autologous epithelium transplantation on various scaffolds to cover tissue loss in oral cavity : long-term observation
Novel Solid Silicon Oxycarbide Unmodified Carbon Nanotube Composite Coating: Structure, Topography and Mechanical Properties
A silicon oxycarbide-carbon nanotube coating on steel was synthesized using a novel approach utilizing unmodified carbon nanotubes (CNT), silane surfactant and large monomer-based silsesquioxane sol. This enabled the creation of very stable carbon nanotube dispersion, which in turn resulted in homogenous layers obtained in a simple dip-coating process. The samples were annealed in 800 °C in argon to obtain a uniform glassy silicon oxycarbide-based composite from a silsesquioxane precursor. The layers’ morphology and nanomechanical properties were investigated using a number of methods, including infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), nanoindentation, Accelerated Property Mapping (XPM) and Quantitative Nanomechanical Mapping—an Atomic Force Microscopy method (QNM-AFM)
Photoinduced energy and electron transfer in micellar multilayer films
Micellar multilayer films were prepared from an amphiphilic comb-like polycation (“polysoap”) and the polyanion poly(styrene sulfonate) (PSS) using alternate polyelectrolyte layer-by-layer (LbL) self-assembly. Linear growth of the film thickness was evidenced by UV–vis spectroscopy and spectroscopic ellipsometry. Imaging by atomic force microscopy (AFM) indicated that the micellar conformation adopted by the polycation in solutions was preserved in the films. Thus, hydrophobic photoactive molecules, which were solubilized by the hydrophobic nanodomains of the micellar polymer prior to deposition, could be transferred into the films. Photoinduced energy transfer was observed in the nanostructured multilayers between naphthalene (donor) and perylene (acceptor) molecules embedded inside the polymer micelles. The efficiency of the energy transfer process can be controlled to some extent by introducing spacer layers between the layers containing the donor or acceptor, revealing partial stratification of the micellar LbL films. Also, photoinduced electron transfer was evidenced between perylene (donor) and butyl viologen (acceptor) molecules embedded inside the multilayers by steady-state fluorescence spectroscopy. The obtained photoactive nanostructures are promising candidates for solar-to-chemical energy conversion systems
Macromonomers as a Novel Way to Investigate and Tailor Silicon-Oxycarbide-Based Materials Obtained from Polymeric Preceramic Precursors
It has been shown that bifunctional monomers (D units), which are used to increase the carbon content in silicon oxycarbide precursors, can form volatile oligomers, thus affecting the amount of carbon available during the transition into the final material in the annealing process. Additionally, an uneven distribution of carbon-rich mers may lead to the formation of a free-carbon phase, instead of the incorporation of carbon atoms into the silicon matrix. In this study, a novel two-step approach was utilized. Firstly, a macromonomer containing a number of structural units with precise structure was synthesized, which was later polycondensed into a ceramic precursor. Chlorodimethylsilane modified 2,4,6,8-tetramethylcyclotetrasiloxane was used as a silicon oxycarbide precursor monomer containing both T and D structural units (i.e., silicon atoms bonded to three and two oxygen atoms, respectively), with well-defined interconnections between structural units. Such a macromonomer prevents the formation of small siloxane rings, and has a very limited number of possible combinations of structural units neighboring each silicon atom. This, after investigation using IR, XRD, TG and elemental analysis, gave insight into the effect of “anchoring” silicon atoms bonded to two methyl groups, as well as the impact of their distribution in comparison to the materials obtained using simple monomers containing a single silicon atom (structural unit)
Photocrosslinkable diazoresin/pectin films : synthesis and application as cell culture supports
Effect of Different Levels of Calcium and Addition of Magnesium in the Diet on Garden Snails’ (<i>Cornu aspersum</i>) Condition, Production, and Nutritional Parameters
Edible snails are an attractive protein source due to their high growth rate, cost-efficiency, and nutritional value. Calcium is crucial for snail growth, reproduction, and shell formation, while magnesium plays a role in enzyme function and muscle tone. This study aimed to optimise calcium and magnesium levels in Cornu aspersum diets to optimise the production and technological characteristics of the derived animal products. Snails were fed specific diets in controlled conditions with varying calcium and magnesium levels (44.3, 66.1, 88.7, 103.5 Ca g/kg feed and 3.3, 5.6, 7.2 Mg g/kg feed) for four months. Their growth, shell characteristics, and meat composition were evaluated. As calcium in the feed increased, carcass and shell weights were higher. Also, the crushing force of the shells was higher with increasing amount of calcium in the feed. In the group with 10.35% calcium and 0.72% magnesium, snail growth significantly slowed down after three months, with lower mortality. It is suggested that a shortened fattening cycle by 3–4 weeks compared to the magnesium-free diet is possible. However, based on meat, shell, mortality, and feed intake analysis, a 0.56% magnesium concentration in the feed seems to give better results, as magnesium content at 0.72% might be toxic to snails. Further investigation is to confirm the possibility of neutralising the negative effects of magnesium in the diet through increasing calcium and phosphorus intake
Photoinduced Energy and Electron Transfer in Micellar Multilayer Films
Micellar multilayer films were prepared
from an amphiphilic comb-like
polycation (“polysoap”) and the polyanion poly(styrene
sulfonate) (PSS) using alternate polyelectrolyte layer-by-layer (LbL)
self-assembly. Linear growth of the film thickness was evidenced by
UV–vis spectroscopy and spectroscopic ellipsometry. Imaging
by atomic force microscopy (AFM) indicated that the micellar conformation
adopted by the polycation in solutions was preserved in the films.
Thus, hydrophobic photoactive molecules, which were solubilized by
the hydrophobic nanodomains of the micellar polymer prior to deposition,
could be transferred into the films. Photoinduced energy transfer
was observed in the nanostructured multilayers between naphthalene
(donor) and perylene (acceptor) molecules embedded inside the polymer
micelles. The efficiency of the energy transfer process can be controlled
to some extent by introducing spacer layers between the layers containing
the donor or acceptor, revealing partial stratification of the micellar
LbL films. Also, photoinduced electron transfer was evidenced between
perylene (donor) and butyl viologen (acceptor) molecules embedded
inside the multilayers by steady-state fluorescence spectroscopy.
The obtained photoactive nanostructures are promising candidates for
solar-to-chemical energy conversion systems