Inverse data envelopment analysis model to preserve relative efficiency values: The case of variable returns to scale

This paper studies the inverse Data Envelopment Analysis (inverse DEA) for the case of variable returns to scale (inverse BCC). The developed inverse BCC model can preserve relative efficiency values of all decision making units (DMUs) in a new production possibility set composing of all current DMUs and a perturbed DMU with new input and output values. We consider the inverse BCC model for a resource allocation problem, where increases of some outputs and decreases of the other outputs of the considered DMU can be taken into account simultaneously. The inverse BCC problem is in the form of a multi-objective nonlinear programming model (MONLP), which is not easy to solve. We propose a linear programming model, which gives a Pareto-efficient solution to the inverse BCC problem. However, there exists at least an optimal solution to the proposed model if and only if the new output vector is in the set of current production possibility set. The proposed approach is illustrated via a case study of a motorcycle-part company.     

A Virus‐Mimicking pH‐Responsive Acetalated Dextran‐Based Membrane‐Active Polymeric Nanoparticle for Intracellular Delivery of Antitumor Therapeutics

Achieving cellular internalization and endosomal escape remains a major challenge for many antitumor therapeutics, especially macromolecular drugs. Viral drug carriers are reported for efficient intracellular delivery, but with limited choices of payloads. In this study, a novel polymeric nanoparticle (ADMAP) is developed, resembling the structure and functional features of a virus. ADMAP is synthesized by grafting endosomolytic poly(lauryl methacrylate‐co‐methacrylic acid) on acetalated dextran. The endosomolytic polymer mimics the capsid protein for endosomal escape, and acetalated dextran resembles the viral core for accommodating payloads. After polymer synthesis, the subsequent controlled nanoprecipitation on a microfluidic device yields uniform nanoparticles with high encapsulation efficiency. At late endosomal pH (5.0), the ADMAP particles successfully destabilize endosomal membranes and release the drug payloads synergistically, resulting in a greater therapeutic efficacy compared with that of free anticancer drugs. Further conjugation of a tumor‐penetrating peptide enhances the antitumor efficacy toward 3D spheroids and finally leads to spheroid disintegration. The unique structure along with the synergistic endosomal escape and drug release make ADMAP nanoparticles favorable for intracellular delivery of antitumor therapeutics.     

Ecdysteroids from Chenopodium quinoa Willd., an ancient Andean crop of high nutritional value

Chenopodium quinoa Willd. (=quinoa) is a crop cultivated since ancient times by the Incas, which has a high nutritional value. Quinoa belongs to Chenopodiaceae, a family containing many ecdysteroid-containing species, including spinach.     

Preparation of spent brewer's yeast β-glucans for potential applications in the food industry

A preparation of β‐glucan, obtained from spent brewer's yeast, was evaluated for potential food applications. This material was autolysed and the cell walls that were obtained were homogenized, extracted firstly with alkali, then with acid, and then spray dried. Effects of the homogenization on the chemical composition, rheological properties and functional properties of β‐glucan were investigated. Homogenized cell walls exhibited higher β‐glucan content and apparent viscosity than those which had not been homogenized because of fragmentation of the cell walls. When compared with commercial β‐glucan from baker's yeast, it was found that the β‐glucan obtained from this study had higher apparent viscosity, water‐holding capacity and emulsion stabilizing capacity, but very similar oil‐binding capacity. These findings suggest that β‐glucan obtained from brewer's yeast can be used in food products as a thickening, water‐holding, or oil‐binding agent and emulsifying stabilizer.     

Effect of Ag loading on activated carbon doped ZnO for bisphenol A degradation under visible light

Silver modified activated carbon doped zinc oxide (Ag/AC-ZnO) was synthesized via a calcination-electroless deposition route. The samples were characterized by X-ray powder diffractometry, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity of the Ag/AC-ZnO was evaluated for bisphenol A degradation in the presence of H₂O₂ under visible light irradiation. The archived results showed that the photocatalytic activity of the Ag/AC-ZnO was higher than that of AC-ZnO and pure ZnO. The cytotoxicity of the bisphenol A after photocatalysis under visible light irradiation was tested using L929 mouse fibroblast cells and the obtained results indicated that the treated bisphenol A solution exhibited no cytotoxicity against normal cells.     

Colorimetric sensor based on polymeric thin film for arsenic quantitation using colour response calibration

A simple, low-cost and portable sensor for colorimetric determination of As(III) was developed. The sensing is carried out using a microcentrifuge tube as a mini-reactor, where an Fe(III)-1,10-phenanthroline doped polyvinyl alcohol thin film is cast on the underside of the cap. Once Fe(III)-1,10-phenanthroline is reduced by arsine gas generated in situ from As(III), yielding the Fe(II)-1,10-phenanthroline complex, the red coloured product can be detected using colour analysis software. The As(III) content is then determined based upon the colour intensity of Fe(II)-1,10-phenanthroline on the film. Experimental conditions were optimised, and parameters affecting the complex formation and arsenic speciation were investigated. The method developed proved to be a selective colorimetric sensor for As(III). More significantly, the device could be directly used to detect As(III) in the field without any sample preparation requirements. The recovery for industrial wastewater and groundwater was found to be 97.5%-104.0%. Hence, the thin film-based test kit is easy to operate, portable and practical for the measurement of As(III) in the field.