Electrospun herbal nanofibrous wound dressings for skin tissue engineering

Synthetic polymeric membranes are used for biomedical applications due to their remarkable structural, mechanical, and biocompatible behavior. Polycaprolactone (PCL) is a biopolymer widely used for tissue engineering applications, but the major limitation of PCL polymer is that it is hydrophobic in nature. The major focus of the work is to study the degradation and wettability behavior of aloe vera (AV)-incorporated elctrospun matrices. The AV-incorporated matrices degraded at a faster rate compared to PCL matrices. The hydrophilicity of the mat increased on blending the polymer with AV. Fibroblasts cells cultured on the PCL-AV showed rapid proliferation compared to that of pristine PCL mat.     

Gelatin shells strengthen polyvinyl alcohol core–shell nanofibers

In this study, polyvinyl alcohol (PVA) and gelatin are coaxially electrospun into core–shell nanofibers to derive mechanical strength from PVA and bioactivity from gelatin. The core–shell nanofibers with PVA in the core and gelatin in the shell display an increased Young's modulus, improved tensile strength, and reduced plastic deformation than PVA nanofibers. When the order of gelatin and PVA is reversed in the core–shell nanofibers, however, the mechanical strengthening effects disappear. It thus suggests that the bioactive yet mechanically weak gelatin shell improves the molecular alignment of PVA in the core and transforms the weak, plastic PVA into a strong, elastic PVA. The use of a gelatin shell as a biological coating and a protecting barrier to strengthen the core in electrospinning presents a new strategy for fabricating advanced composite nanofibers.     

Flowfield initialization and approach to stationary conditions in unsteady combustion simulations

The initial transient leading to stationary conditions in unsteady combustion simulations is investigated by considering flow establishment in model combustors. Quiescent initial conditions with the chamber initially filled with an inert, hot gas are used to provide physically realistic starting conditions and robust, reliable combustion initiation. Transient processes are visualized by using a distinct initial fluid in the combustor whose concentration is tracked as it is expelled. The duration of the transient is shown to be dependent on the characteristic turn-over time for recirculation zones and the time for the chamber pressure to reach steady conditions. Substantial changes in the initial condition did not materially affect the length of the transient. Different combustor geometries changed the ratio of pressure equilibration time and species replenishment time, but did not have a major effect on the overall duration of the transient. Representative comparisons of the time-averaged, stationary results with experiment are presented to document the computations.     

Possibilities to increase the quality in gluten-free bread production: an overview

The market for gluten-free products is increasing. Owing to better diagnostic methods, more and more people are identified to have coeliac diseases. Production of bakery products that do not harm these people is a big challenge for bakers and cereal scientists in the twenty-first century. The use of different cereals and flours makes it necessary to find possibilities to take over the task of gluten by other flour ingredients, by the addition of different components, by different flour and dough treatment or by changing the method of baking. The purpose of this review is to give an overview about the various possibilities to increase the baking quality of gluten-free bakery products, increasing their water-binding capacity, uniform the crumb structure and increase the final bread volume. All the listed methods and ingredients are already in single use helpful to increase the quality in gluten-free bread production.     

Soft PVC foams: Study of the gelation,fusion and foaming processes. III. Mixed phthalate ester plasticizers

The foaming of PVC (poly(vinyl chloride)) plastisols is a complex combination of simultaneous processes, involving the curing and structural changes of the plastisol, the gas generation and the foam formation. Our comprehensive study of such processes and of the influence of plasticizer on the foam quality has shown that all the processes involved have to be adequately synchronized to obtain foams of the required quality. A series of plastisols prepared by mixing a high and a low compatible phthalate ester plasticizer in several proportions (100/0, 75/25, 50/50, 25/75, 0/100 ratios) has been studied and characterized (by means of rheology, calorimetry, thermal stability, thermomechanical properties, density, and foam morphology), to study the influence of the plasticizer in such processes with changing compatibility. We found expectable rheological and calorimetric behavior regarding the plastisols without curing; however we experienced nonlinear (unexpected) behaviors in cases of foams and plastisols being cured. To confirm such behavior and our hypothesis regarding the possible plasticizer evaporation, the thermal stability of the plastisols, precured samples and foams have been studied by themorgravimetric analysis (TGA). According to our results it can be deduced that the plasticizer loss occurring in some cases during the production of the foams or the specimens being characterized, plays an important role in the foaming process and also influences the foam quality. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Quantitative analysis of phenolic components and glycoalkaloids from 20 potato clones and in vitro evaluation of antioxidant,cholesterol uptake,and neuroprotective activities

Potato (Solanum tuberosum L.) is one of the most important food crops in the world and provides essential nutrients. With an aim to develop potato varieties for functional food or nutraceutial applications, we have conducted metabolomic profiling, total phenolics, chlorogenic acid, anthocyanins, and glycoalkaloids analyses on 20 selected potato clones within the Canadian potato breeding program of Agriculture and Agri-Food Canada. Pigmented potatoes in general contain higher levels of phenolic components, including chlorogenic acid and anthocyanins. Levels of phenolics were retained with granulation processing of pigmented potato tubers, but glycoalkaloids were significantly reduced with granulation. The pigmented potatoes also have higher antioxidant activity reaching up to 35% of that for berries, measured as their potency in scavenging DPPH radicals. Extracts of the 20 potato clones (peel, tuber, and granule) were also evaluated for in vitro effects on liver LDL cholesterol uptake and protection of cortical neurons from cell death caused by oxygen glucose deprivation (OGD). These potato extracts in general showed mild activity in enhancing LDL cholesterol uptake in liver HepG2 cells, and also protected cortical neurons against OGD induced cell death, with extracts from granules of six of the potato clones showing significant neuroprotective effects. The bioactive components are not dependent on pigmentation of potato clones. These novel bioactivities identified in potatoes warrant in-depth investigations in the future. Taken together, our results provide further evidence for the enhanced health beneficial components in potato.     

Catastrophic inversion and rheological behavior in soy lecithin and Tween 80 based food emulsions

Emulsions inversion occurs in many industrial processes and may be influenced by the formulation conditions, composition and emulsification protocols. In this work, the influence of emulsifiers and stirring on catastrophic inversion (O/W to W/O) was evaluated. Emulsions were prepared with different stirring rates, using soy lecithin and Tween 80, at 2 and 5 wt%. The aqueous phase was distilled water with 1 wt% NaCl and the oil phase was soy oil. These emulsions were analyzed by conductivity, stability, microscopy and rheology assays. The most stable emulsions presented inversion with a smaller amount of the external phase. Rheological analysis showed that, with a higher concentration of emulsifier, it is better to use Tween 80 when lower viscosity is desired, while soy lecithin is more appropriate for higher viscosity products. The oscillatory tests showed that while the emulsions prepared using Tween 80 exhibited concentrated solution behavior, those prepared with soy lecithin exhibited strong gel behavior.     

Study on effect of blend ratio on thermal comfort properties of cotton/nylon-blended fabrics with high-performance Kermel fibre

This study presents the thermal comfort properties of woven fabrics made of Kermel, cotton/nylon and cotton/nylon /Kermel-blended yarns. Our aim in this study is to combine the high comfort properties of cotton/nylon fibres with high thermal protective properties of Kermel fibre in different woven fabrics. Thus, Kermel (100%), cotton/nylon (50:50) and four blends of the 50% cotton fibres with nylon and Kermel (40:10, 30:20, 20:30 and 10:40) were spun on a ring-spinning frame and twisted into two-folded yarns with the same yarn count of 30/2(Ne) and twist level of 560 TPM. Using the produced yarns, woven fabrics with identical characteristic and structure were also produced. Then, the thermal comfort and physical properties of fabrics were studied in terms of fabric porosity, thermal resistance, thermal conductivity, water vapour resistance and air permeability. The results show that the porosity, air permeability and thermal resistance increase with Kermel fibre blend ratio. Conversely, the water vapour resistance decreases with increase of Kermel fibre blend ratio up to 40%, while 100% Kermel-woven fabric exhibits a higher water vapour resistance value. Nevertheless, the thermal conductivity of cotton/nylon-blended Kermel woven fabric is unchanged with increase of Kermel fibre blend ratio up to 40%, whereas at 100% Kermel fibre blend ratio, the lowest thermal conductivity is obtained. The obtained results implied that woven fabric produced from cotton/nylon (50/10) blended with 40% Kermel fibre resulted in proper thermal comfort properties.     

Low temperature TiO2 rutile phase thin film synthesis by chemical spray pyrolysis (CSP) of titanyl acetylacetonate

Rutile phase TiO₂ thin films have been synthesized using chemical spray pyrolysis of titanyl acetylacetonate TiAcAc in ethanol at 500 °C. The first part of the paper focuses on the thermal decomposition behavior of the precursor by simultaneous thermogravimetry and differential thermal analysis (TG/DTA) coupled with differential scanning calorimetry (DSC). The second part of the paper focuses on the evolution of TiO₂ thin films and their structural transformation with substrate temperature. XRD revealed amorphous TiO₂ thin film at low substrate temperatures (<350 °C) and on high substrate temperatures anatase (3.84 g/cm³) or rutile (4.25 g/cm³) crystalline structure was obtained. The lattice constant, grain size, microstrain and the dislocation density of the film were obtained from the peak width. FTIR spectra of both anatase and rutile TiO₂ revealed stretching vibration of the Ti–O bond for tetrahedral and octahedral surroundings of the titanium atom. Scanning electron micrograph showed the compactness of the rutile film.