Lecithin blended polyamide-6 high aspect ratio nanofiber scaffolds via electrospinning for human osteoblast cell culture

In this study, we focused on the preparation and characterization of lecithin blended polyamide-6 nanofibers via an electrospinning process for human osteoblastic (HOB) cell culture applications. The morphological, structural characterizations and thermal properties of polyamide-6/lecithin nanofibers were determined by using scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry (TGA). SEM images revealed that the nanofibers were well-oriented with good incorporation of lecithin. FT-IR results indicated the presence of amino groups of lecithin in the blended nanofibers. TGA analysis revealed that the onset degradation temperature decreased with increasing lecithin content in the blended nanofibers. The morphological features of cells attached on polyamide-6/lecithin nanofibers were confirmed by SEM. The adhesion, viability and proliferation properties of osteoblast cells on the polyamide-6/lecithin blended nanofibers were analyzed by in vitro cell compatibility test. This study demonstrated the non-cytotoxic behavior of electrospun polyamide-6/lecithin nanofibers for the osteoblast cell culture.     

Monte Carlo-based inverse model for calculating tissue optical properties. Part I: Theory and validation on synthetic phantoms

A flexible and fast Monte Carlo-based model of diffuse reflectance has been developed for the extraction of the absorption and scattering properties of turbid media, such as human tissues. This method is valid for a wide range of optical properties and is easily adaptable to existing probe geometries, provided a single phantom calibration measurement is made. A condensed Monte Carlo method was used to speed up the forward simulations. This model was validated by use of two sets of liquid-tissue phantoms containing Nigrosin or hemoglobin as absorbers and polystyrene spheres as scatterers. The phantoms had a wide range of absorption (0-20 cm(-1)) and reduced scattering coefficients (7-33 cm(-1)). Mie theory and a spectrophotometer were used to determine the absorption and reduced scattering coefficients of the phantoms. The diffuse reflectance spectra of the phantoms were measured over a wavelength range of 350-850 nm. It was found that optical properties could be extracted from the experimentally measured diffuse reflectance spectra with an average error of 3% or less for phantoms containing hemoglobin and 12% or less for phantoms containing Nigrosin.     

Significance of thermal radiation on dusty fluid flow over a stretching rotating disk with convective boundary condition

This paper explores the flow of dusty fluid over a stretching rotating disk with thermal radiation. Further, the convective boundary condition is considered in this modeling. The described governing equations are reduced to ordinary differential equations by using apt similarity transformations and then they are numerically solved using Runge–Kutta–Fehlberg-45 scheme. To gain a clear understanding of the current boundary layer flow problem, the graphical results of the velocity and thermal profiles, shear stresses at the disk, and Nusselt number are drawn. Results reveal that the increase in the value of the porosity parameter reduces the velocity of both particle and fluid phases. The increase in the value of the Biot number improves the temperature gradient of both particle and fluid phases. The rise in the value of the radiation parameter advances the heat transference of both phases. The rise in the value of the Biot number improves the rate of heat transfer. Finally, increasing the value of the radiation parameter improves the rate of heat transfer.     

Effect of enzyme assisted extraction on quality and yield of volatile oil from black pepper and cardamom

The present study investigated the effect of enzyme pre-treatment on extraction of active compounds from spices, namely, black pepper and cardamom. A mixture of enzymes, namely, Lumicellulae (a mixture of cellulase, β-glucanase, pectinase, and xylanase), was used for the pre-treatment of black pepper and cardamom. The pre-treatment of spices with enzyme increased the yield of essential oil. The GC and GC-MS evaluation of the essential oil showed that the major active components in spices, such as, β-caryophyllene in black pepper and α-terpenyl acetate in cardamom, markedly increased from 15.03 to 25.58 and 38.91 to 48.6%, respectively, on enzyme treatment as compared with the untreated control. The improvement in the yield and the major components of essential oil was attributed to the destruction of the cell wall structure by the enzymes pre-treatment which was substantiated with microscopical images using SEM.     

Sequential estimation of optical properties of a two-layered epithelial tissue model from depth-resolved ultraviolet-visible diffuse reflectance spectra

A method for estimating the optical properties of two-layered media (such as squamous epithelial tissue) over a range of wavelengths in the ultraviolet-visible spectrum is proposed and tested with Monte Carlo modeling. The method first used a fiber-optic probe with angled illumination and the collection fibers placed at a small separation (or=1000 microm) was used to detect diffuse reflectance preferentially from the bottom layer. A second Monte Carlo-based inverse model for a two-layered medium was applied to estimate the bottom layer optical properties, as well as the top layer thickness, given that the top layer optical properties have been estimated. The results of Monte Carlo validation show that this method works well for an epithelial tissue model with a top layer thickness ranging from 200 to 500 microm. For most thicknesses within this range, the absorption coefficients were estimated to within 15% of the true values, the reduced scattering coefficients were estimated to within 20% and the top layer thicknesses were estimated to within 20%. The application of a variance reduction technique to the Monte Carlo modeling proved to be effective in improving the accuracy with which the optical properties are estimated.     

Antimicrobial activity of electrospun polyurethane nanofibers containing composite materials

We report on the preparation and characterization of electrospun polyurethane nanofibers containing silver, cactus, rosin and Scutellariae Radix. The utilized polyurethane nanofibers containing different composite materials were prepared by a simple dip coating method. The morphology, structure and thermal characteristics of as-prepared composite nanofibers were studied by scanning electron microscopy, X-ray diffraction, Fourier transform infrared, Raman spectroscopy and thermogravimetric analysis. The antimicrobial activity of the composite nanofibers was tested against two common food borne pathogenic bacteria, Staphylococcus aureus and Escherichia coli, by the minimum inhibitory concentration method. Our results demonstrated that more pronounced antimicrobial activities were observed for the composite nanofibers. Overall, the fabrication of cheap, stable and effective material with excellent antimicrobial activity can be utilized to inhibit the microbial growth associated with food stuff.     

Novel electrospun nanofiber mats as effective catalysts for water photosplitting

Two novel photocatalysts based on ceramic materials for hydrogen production from water splitting under the solar radiation are introduced. CdS-doped and CdS–PdS-doped poly(vinyl acetate) electrospun nanofiber mats reveal good activity toward water photosplitting. The efficient ceramic nanoparticles were in situ synthesized in the polymer solution which was subjected to the electrospinning process. CdS–PdS-doped poly(vinyl acetate) nanofibers produce more hydrogen compared to the naked CdS NPs. Immobilization of the CdS and CdS–PdS nanoparticles inside the polymer nanofibers is an effective strategy to overcome the photocorrosion and toxicity problems of the CdS-based materials.     

Enhanced low-complexity pruning for corner detection

Low-complexity corner detection is essential for many real-time computer vision applications that need to be executed on low-cost/low-power embedded platforms such as robots. The widely used Shi–Tomasi and Harris corner detectors become prohibitive in such platforms due to their high computational complexity, which is attributed to the need to apply a complex corner measure on the entire image. In this paper, we introduce a novel and computationally efficient technique to accelerate the Shi–Tomasi and Harris corner detectors. The proposed technique consists of two steps. In the first step, the complex corner measure is replaced with simple approximations to quickly prune away non-corners. In the second step, the complex corner measure is applied to a small corner candidate set obtained after pruning. Evaluations using standard image benchmarks show that the proposed pruning technique achieves up to 75 % speedup on the Nios-II platform, while yielding corners with comparable or better accuracy than the conventional Shi–Tomasi and Harris detectors.