Refolding of β-galactosidase: microfluidic device for reagent metering and mixing and quantification of refolding yield

We have developed a device that uses microfluidic valves and pumps to meter reagents for subsequent mixing with application to refolding of the protein β-galactosidase. The microfluidic approach offers the potential advantages of automation, cost-effectiveness, compatibility with optical detection, and reduction in sample volumes as opposed to conventional techniques of hand-pipetting or using robotic systems. The device is a multi-layered poly(dimethylsiloxane) on glass device with automated controls for reagent aliquoting and mixing. Refolding experiments have been performed off-chip using existing protocols on the protein β-galactosidase and the refolding yield has been quantified on-chip using fluorescein di-β-d-galactopyranoside, a caged-fluorescent molecule. This work provides the potential to reduce the cost of drug discovery and realization of protein pharmaceuticals.     

Electrical and Electromagnetic Interference (EMI) shielding properties of hexagonal boron nitride nanoparticles reinforced polyvinylidene fluoride nanocomposite films

The hexagonal boron nitride nanoparticles (h-BNNPs) reinforced flexible polyvinylidene fluoride (PVDF) nanocomposite films were prepared via a simple and versatile solution casting method. The morphological, thermal and electrical properties of h-BNNPs/PVDF nanocomposite films were elucidated. The electromagnetic interference (EMI) shielding properties of prepared nanocomposite films were investigated in the X-band frequency regime (8–12 GHz). The EMI shielding effectiveness (SE) was increased from 1 dB for the PVDF film to 11.21 dB for the h-BNNPs/PVDF nanocomposite film containing 25 wt% h-BNNPs loading. The results suggest that h-BNNPs/PVDF nanocomposite films can be used as lightweight and low-cost EMI shielding materials.     

Integrated microfluidic preconcentrator and immunobiosensor

We present a microfluidic biosensor that integrates membrane-based preconcentration with fluorescence detection. The concentration membrane was fabricated in polyacrylamide by an in situ photopolymerization technique at the junction of glass microchannels. Liposomes entrapping sulforhodamine B dye molecules were used for signal amplification. The biotin–streptavidin binding system was a model system for evaluating device performance. Biotinylated liposomes were preconcentrated at the membrane by applying an electric field across the membrane. The electric field causes the liposomes to migrate toward the membrane where they are concentrated by a sieving effect. Two orders of magnitude concentration was achieved after applying the electric field for only 2 min. The concentrated bolus was then eluted toward the detection unit, where the biotinylated liposomes were captured by immobilized streptavidin. The integrated system with the preconcentration module shows a 14-fold improvement in signal as opposed to a system that does not include preconcentration.     

Development of high performance catalysts for the production of vinyl acetate monomer

Two types of highly active and selective vinyl acetate monomer (VAM) catalysts have been developed in our lab via traditional lab preparation and high-pressure reactor performance test methods. Experimental results are presented here. Degussa is now engaged in high-throughput (HT) VAM catalyst powder preparation and HT (50 parallel reactor) testing to accelerate the development of new higher performing commercial catalysts. Our first results on HT are presented here. Though HT systems in both catalyst preparation and testing have existed for over a decade, HT heterogeneous catalyst preparation methods have been very slow to develop. The HT preparation system described here provides a versatile method of preparing commercially relevant catalysts as required by Degusssa. The HT reactor test system described here uses plant operating conditions and provides reliable STY and selectivity data on par with that obtained from conventional lab VAM test systems. Both the HT preparation and HT test systems combined allow for significant increases in the commercialization rate of new catalysts.     

Investigation of Relationship Between Blend Ratio and Yarn Twist on Yarn Properties of Bamboo,Cotton, Polyester,and its Blends

In this study, a series of blended yarns consisting of 80:20 bamboo/cotton, 67:33 bamboo/cotton, 50:50 bamboo/cotton, 33:67 bamboo/cotton, 20:80 bamboo/cotton, 80:20 bamboo/polyester, 67:33 bamboo/polyester, 50:50 bamboo/polyester, 33:67 bamboo/polyester, and 20:80 bamboo/polyester were produced from blends consisting of bamboo/cotton and bamboo/polyester. Besides these, 100% bamboo, 100% cotton, and 100% polyester were also produced. All the yarns were produced with two levels of twist per meter (TPM) 76 and 90. It can be found that the yarn unevenness characteristic was affected by the blended ratio of cotton, polyester, and regenerated bamboo fiber. The drop in tenacity of blended yarns in comparison to the constituents is generally lower which is attributed to the elongation at break of the yarns. The variability in tenacity in respect of 100% polyester yarn is quite high in comparison with other yarns. The yarn elongation at break of bamboo/cotton-blended yarns is found to be lower than those of bamboo/polyester-blended yarns. The variability in the work of rupture is found to be lower for bamboo/cotton-blended yarns. Yarn friction values of the yarns noticed that polyester exhibits the highest value at the TPM of 76. The yarn torque values from which it is noticed that 100% polyester yarns spun with the TPM of 76 have a higher torque in both the wet and dry states. The quality characters of yarn depend upon the ratio of bamboo, cotton, and polyester in the blend ratio.     

Hybrid Core-Shell Polymer Scaffold for Bone Tissue Regeneration

A great promise for tissue engineering is represented by scaffolds that host stem cells during proliferation and differentiation and simultaneously replace damaged tissue while maintaining the main vital functions. In this paper, a novel process was adopted to develop composite scaffolds with a core-shell structure for bone tissue regeneration, in which the core has the main function of temporary mechanical support, and the shell enhances biocompatibility and provides bioactive properties. An interconnected porous core was safely obtained, avoiding solvents or other chemical issues, by blending poly(lactic acid), poly(ε-caprolactone) and leachable superabsorbent polymer particles. After particle leaching in water, the core was grafted with a gelatin/chitosan hydrogel shell to create a cell-friendly bioactive environment within its pores. The physicochemical, morphological, and mechanical characterization of the hybrid structure and of its component materials was carried out by means of infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and mechanical testing under different loading conditions. These hybrid polymer devices were found to closely mimic both the morphology and the stiffness of bones. In addition, in vitro studies showed that the core-shell scaffolds are efficiently seeded by human mesenchymal stromal cells, which remain viable, proliferate, and are capable of differentiating towards the osteogenic phenotype if adequately stimulated.     

Dynamic video anomaly detection and localization using sparse denoising autoencoders

The emergence of novel techniques for automatic anomaly detection in surveillance videos has significantly reduced the burden of manual processing of large, continuous video streams. However, existing anomaly detection systems suffer from a high false-positive rate and also, are not real-time, which makes them practically redundant. Furthermore, their predefined feature selection techniques limit their application to specific cases. To overcome these shortcomings, a dynamic anomaly detection and localization system is proposed, which uses deep learning to automatically learn relevant features. In this technique, each video is represented as a group of cubic patches for identifying local and global anomalies. A unique sparse denoising autoencoder architecture is used, that significantly reduced the computation time and the number of false positives in frame-level anomaly detection by more than 2.5%. Experimental analysis on two benchmark data sets - UMN dataset and UCSD Pedestrian dataset, show that our algorithm outperforms the state-of-the-art models in terms of false positive rate, while also showing a significant reduction in computation time.     

Non-linear impedance characterization of blood cells-derived microparticle biomarkers suspensions

This paper examines the application of higher harmonic Non-Linear Electrochemical Impedance Spectroscopy (NLEIS) to characterization of colloidal suspensions of clinically relevant microparticle biomarkers derived from monocytes (white blood cells). This study expands on previous linear EIS investigations of microparticle biomarkers’ suspensions and NLEIS studies of non-aqueous colloidal systems. Numerical minimization analysis allowed to develop a more accurate equivalent circuit model for the low frequency region (<1 kHz) and provided qualitative insight into the kinetic and physiological parameters of the system. The developed NLEIS characterization method permitted to resolve several remaining ambiguities in interpretation of low-frequency linear impedance experimental results for microparticles’ suspensions. These results support continued development of the NLEIS method validation and instrumentation for microparticle biomarkers’ analysis, further expanding its clinical diagnostic capabilities.     

Automatic multimodal assessment of soft skills in social interactions: a review

Multimedia Tools and Applications - Automatic assessment of soft skills is an interesting problem in social computing. Soft skills are essential to any individual for personal and career...