Poly(3-hydroxybutyrate)-ethyl cellulose based bio-composites with novel characteristics for infection free wound healing application

A series of bio-composites including poly3-hydroxybutyrate [P(3HB)] grafted ethyl cellulose (EC) stated as P(3HB)-EC were successfully synthesised. Furthermore, natural phenols e.g., p-4-hydroxybenzoic acid (HBA) and ferulic acid (FA) were grafted onto the newly developed P(3HB)-EC-based bio-composites under laccase-assisted environment without the use of additional initiators or crosslinking agents. The phenol grafted bio-composites were critically evaluated for their antibacterial and biocompatibility features as well as their degradability in soil. In particular, the results of the antibacterial evaluation for the newly developed bio-composites indicated that 20HBA-g-P(3HB)-EC and 15FA-g-P(3HB)-EC bio-composites exerted strong bactericidal and bacteriostatic activity against Gram- E. coli NTCT 10418 as compared to the Gram+ B. subtilis NCTC 3610. This study shows further that at various phenolic concentrations the newly synthesised bio-composites remained cytocompatible with human keratinocyte-like HaCaT skin cells, as 100% cell viability was recorded, in vitro. As for the degradation, an increase in the degradation rate was recorded during the soil burial analyses over a period of 42 days. These findings suggest that the reported bio-composites have great potential for use in wound healing; covering the affected skin area which may favour tissue repair over shorter periods

Development of bio-composites with novel characteristics: Evaluation of phenol-induced antibacterial, biocompatible and biodegradable behaviours

This paper describes a laccase-assisted grafting of gallic acid (GA) and thymol (T) as functional entities onto the previously developed P(3HB)-g-EC composite. GA-g-P(3HB)-g-EC and T-g-P(3HB)-g-EC bio-composites were prepared by laccase-assisted free radical-induced graft polymerisation of GA and T onto the P(3HB)-g-EC based composite using surface dipping and incorporation technique. The results of the antibacterial evaluation for the prepared composites indicated that 15GA-g-P(3HB)-g-EC, 15T-g-P(3HB)-g-EC and 20T-g-P(3HB)-g-EC composites possessed the strongest bacteriostatic and bactericidal activities against Gram-positive B. subtilis NCTC 3610 and S. aureus NCTC 6571 and Gram-negative E. coli NTCT 10418 and P. aeruginosa NCTC 10662 strains. In this study, we have also tested GA-g-P(3HB)-g-EC and T-g-P(3HB)-g-EC bio-composites for their ability to support and maintain multilineage differentiation of human keratinocyte-like (HaCaT) skin cells in-vitro. From the cytotoxicity results, the tested composites showed 100% viability and did not induce any adverse effect on a HaCaT’s morphology. Finally, in soil burial evaluation, a progressive increase in the degradation rate of GA-g-P(3HB)-g-EC and T-g-P(3HB)-g-EC bio-composites was recorded with the passage of time up to 6 weeks. In summary, our current findings suggest that GA-g-P(3HB)-g-EC and T-g-P(3HB)-g-EC bio-composites are promising candidates for biomedical type applications such as skin regeneration, multiphasic tissue engineering and/or medical implants

Determining Optimal Levels of Nitrogen Fertilizer Using Random Parameter Models

The parameters of yield response functions can vary by year. Past studies usually assume yield functions are nstochastic ‘‘limited’’ stochastic. In this study, we estimate rye– ryegrass yield functions in which all parameters are random. The three functional forms considered are the linear response plateau, the quadratic, and the Spillman-Mitscherlich. Nonstochastic yield models are rejected in favor of stochastic parameter models. Quadratic functional forms fit the data poorly. Optimal nitrogen application recommendations are calculated for the linear response plateau and Spillman-Mitscherlich. The stochastic models lead to smaller recommended levels of nitrogen, but the economic benefits of using fully stochastic crop yield functions are small because expected profit functions are relatively flat for the stochastic yield functions. Stochastic crop yield functions provide a way of incorporating production, uncertainty into input decisions.cereal rye–ryegrass, Monte Carlo, nitrogen, random parameters, stochastic plateau, Production Economics, Q10, C12, D24,

Development of novel antibacterial active, HaCaT biocompatible and biodegradable CA-g-P(3HB)-EC biocomposites with caffeic acid as a functional entity

International audienceWe have developed novel composites by grafting caffeic acid (CA) onto the P(3HB)-EC based material and laccase from Trametes versicolor was used for grafting purposes. The resulting composites were designated as CA-g-P(3HB)EC i.e., P(3HB)-EC (control), 5CA-g-P(3HB)-EC, 10CA-g-P(3HB)-EC, 15CA-g-P(3HB)-EC and 20CA-g-P(3HB)-EC. FT-IR (Fourier-transform infrared spectroscopy) was used to examine the functional and elemental groups of the control and laccase-assisted graft composites. Evidently, 15CA-g-P(3HB)-EC composite exhibited resilient antibacterial activity against Gram-positive and Gram-negative bacterial strains. Moreover, a significant level of biocompatibility and biodegradability of the CA-g-P(3HB)-EC composites was also achieved with the human keratinocytes-like HaCaT cells and soil burial evaluation, respectively. In conclusion, the newly developed novel composites with multi characteristics could well represent the new wave of biomaterials for medical applications, and more specifically have promising future in the infection free would dressings, burn and/or skin regeneration field due to their sophisticated characteristics

The Role of Relapse Prevention and Goal Setting in Training Transfer Enhancement

This article reviews the effect of two post-training transfer interventions (relapse prevention [RP] and goal setting [GS]) on trainees’ ability to apply skills gained in a training context to the workplace. Through a review of post-training transfer interventions literature, the article identifies a number of key issues that remain unresolved or underexplored, for example, the inconsistent results on the impact of RP on transfer of training, the lack of agreement on which GS types are more efficient to improve transfer performance, the lack of clarity about the distinction between RP and GS, and the underlying process through which these two post-training transfer interventions influence transfer of training. We offer some recommendations to overcome these problems and also provide guidance for future research on transfer of training

Colour Relations in Form

The orthodox monadic determination thesis holds that we represent colour relations by virtue of representing colours. Against this orthodoxy, I argue that it is possible to represent colour relations without representing any colours. I present a model of iconic perceptual content that allows for such primitive relational colour representation, and provide four empirical arguments in its support. I close by surveying alternative views of the relationship between monadic and relational colour representation

Sail optimization for upwind sailing: application in a Tornado, the Olympic class catamaran.

A study of a boat’s motion is carried out in order to analyze the aerodynamic properties of the optimal sail for obtaining the maximum velocity when sailing to windward. The mechanics study shows the optimal CL and CD for a given sail and how the shape of the aerodynamic polar of the sail should be. A parametrical analysis of the aerodynamics of a sail is then carried out varying the maximum camber, position of the maximum camber in the chord direction and position of the maximum camber in the mast direction. The parametric analysis is done numerically with a vortex lattice method (VLM) and experimentally in a wind tunnel. The results show that the influence of the relevant parameters studied can be reduced to the variation of two parameters, A and B, defining the polar of the sail, CD = B + A2CL 2; and the influence of parameters A and B on the maximum VMG obtainable are calculated