Biodegradable polymers have significant potential in biotechnology and bioengineering. However, for some applications, they are limited by their inferior mechanical properties and unsatisfactory compatibility with cells and tissues. A strong, biodegradable, and biocompatible elastomer could be useful for fields such as tissue engineering, drug delivery, and in vivo sensing. We designed, synthesized, and characterized a tough biodegradable elastomer from biocompatible monomers. This elastomer forms a covalently crosslinked, three-dimensional network of random coils with hydroxyl groups attached to its backbone. Both crosslinking and the hydrogen-bonding interactions between the hydroxyl groups likely contribute to the unique properties of the elastomer. In vitro and in vivo studies show that the polymer has good biocompatibility. Polymer implants under animal skin are absorbed completely within 60 days with restoration of the implantation sites to their normal architecture.
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"Crude glycerol shows a high potential for becoming a useful industrial feedstock, nevertheless, the variability on its composition remains as a barrier for the direct utilization of crude glycerol in commercial scale processes. Biodegradable elastomeric polyesters have been synthesized using pure glycerol in polycondensation reactions followed by curing steps (Halpern et al., 2014; Li et al., 2013; Migneco et al., 2009; Nagata et al., 1999; 1996; Wang et al., 2002). These materials have been proposed as soft tissue replacement alternatives, due to the biocompatibility and biodegradable nature of its constituent monomers. "
[Show abstract][Hide abstract]ABSTRACT: Path analysis was done on different morphological,
physiological and oil quality traits of 15, six-years old candidate plus
trees of Jatropha curcas to assess their direct and indirect effect on
oil yield. Principal component analysis was subsequently done to assess
the pattern of the variations in characters and segregate the traits to
distinguish parental accessions for plant improvement. Total chlorophyll
had a positive direct effect on oil yield and also had indirect effect
through single seed weight, single fruit weight and oil content. Male to
female flower ratio had negligible direct effect on oil yield but had
considerable indirect effect through seed yield per plant. Seed weight,
fruit weight and seed yield plant-1 had a high direct effect on oil yield
and also had indirect effect through oil content and thus found suitable
for direct selection. The first five principal components contributed
75.5% of the total variability. The accessions JCN-14, JCN-08 and JCN-09
had very high values for the first component, while JCN-04 and JCN-05 had
lower values for all these variables.
Full-text · Article · Mar 2016 · Industrial Crops and Products
"PGS was synthesized as following process . In brief, the equimolar amounts of glycerol and sebacic acid (Table S1) were combined by melting at 125 C under nitrogen atmosphere for 6 h, and then the pressure was reduced to 5 kPa and the reaction was conducted for another 7 h. "
[Show abstract][Hide abstract]ABSTRACT: Myelination of Schwann cells (SCs) is critical for the success of peripheral nerve regeneration, and biomaterials that can promote SCs’ neurotrophin secretion as scaffolds are beneficial for nerve repair. Here we present a biomaterials-approach, specifically, a highly tunable conductive biodegradable flexible polyurethane by polycondensation of poly(glycerol sebacate) and aniline pentamer, to significantly enhance SCs’ myelin gene expression and neurotrophin secretion for peripheral nerve tissue engineering. SCs are cultured on these conductive polymer films, and the biocompatibility of these films and their ability to enhance myelin gene expressions and sustained neurotrophin secretion are successfully demonstrated. The mechanism of SCs’ neurotrophin secretion on conductive films is demonstrated by investigating the relationship between intracellular Ca2+ level and SCs’ myelination. Furthermore, the neurite growth and elongation of PC12 cells are induced by adding the neurotrophin medium suspension produced from SCs-laden conductive films. These data suggest that these conductive degradable polyurethanes that enhance SCs’ myelin gene expressions and sustained neurotrophin secretion perform great potential for nerve regeneration applications.
"(a) The rotational motion of each bar about its longitudinal axis is ignored (b) Tendons are linearly elastic and massless compared to bars and the membrane. Note that modern elastomers enable linear elastic behavior for large strains (Wang et al., 2002; Lee et al., 2009; Sonnenschein, 2013) (c) The gravitational field is ignored, and no external force is applied to the system (d) A homogeneous membrane in the shape of a convex polygon in the undeformed configuration is used (e) Since the membrane is very thin, its bending stiffness and shear stiffness are ignored (f) The mechanics of wrinkles generated on the membrane is not modeled (g) Tendons and the membrane cannot be compressed (i.e. they can carry only tensile loads) "
[Show abstract][Hide abstract]ABSTRACT: This paper investigates the possibility of using active individual blade pitch control for positioning moored ocean current turbines within an array. Using a numerical simulation of a representative ocean current turbine it is shown that harmonic blade oscillations with amplitudes of 1.5° can be used to displace an ocean current turbine laterally by a distance equal to one rotor diameter, when the mooring cable length is approximately 30 times the diameter of the rotor blade. For current flow directions that would result in a downstream turbine operating in the wake of an upstream system at a distance of 10 diameters, this technique could be used to reduce the power loss of the downstream system from about 50% (caused by the reduced flow speed available in the turbine wake) to the 1.2% power loss associated with the suggested control approach.
Full-text · Article · Jan 2016 · International Journal of Marine Energy