On the Independent Set Interdiction Problem

The purpose of the independent set interdiction problem in the weighted graph $G$ is to determine a set of vertices $R^*$ such that the weight of the maximum independent set in $G-R^*$ is minimized. We define an approximate solution for this problem. Then, an upper bound for the relative error of this problem is obtained. We show that the limit of the relative error of the independent set interdiction problem in some subclasses of the generalized Petersen graphs is zero as the number of vertices tends to infinity

On-chip polyelectrolyte coating onto magnetic droplets-towards continuous flow assembly of drug delivery capsules

Polyelectrolyte (PE) microcapsules for drug delivery are typically fabricated via layer-by-layer (LbL) deposition of PE layers of alternating charge on sacrificial template microparticles, which usually requires multiple incubation and washing steps that render the process repetitive and time-consuming. Here, ferrofluid droplets were explored for this purpose as an elegant alternative of templates that can be easily manipulated via an external magnetic field, and require only a simple microfluidic chip design and setup. Glass microfluidic devices featuring T-junctions or flow focusing junctions for the generation of oil-based ferrofluid droplets in an aqueous continuous phase were investigated. Droplet size was controlled by the microfluidic channel dimensions as well as the flow rates of the ferrofluid and aqueous phases. The generated droplets were stabilised by a surface active polymer, polyvinylpyrrolidone (PVP), and then guided into a chamber featuring alternating, co-laminar PE solutions and wash streams, and deflected across them by means of an external permanent magnet. The extent of droplet deflection was tailored by the flow rates, the concentration of magnetic nanoparticles in the droplets, and the magnetic field strength. PVP-coated ferrofluid droplets were deflected through solutions of polyelectrolyte and washing streams using several iterations of multilaminar flow designs. This culminated in an innovative "Snakes-and-Ladders" inspired microfluidic chip design that overcame various issues of the previous iterations for the deposition of layers of anionic poly(sodium-4-styrene sulfonate) (PSS) and cationic poly(fluorescein isothiocyanate allylamine hydrochloride) (PAH-FITC) onto the droplets. The presented method demonstrates a simple and rapid process for PE layer deposition in <30 seconds, and opens the way towards rapid layer-by-layer assembly of PE microcapsules for drug delivery applications.The authors thank the Royal Embassy of Saudi Arabia Cultural Bureau in London and Albaha University in Saudi Arabia for funding. J.G.-P., E.B. and I.O. acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (project CTQ2015-66078-R (MINECO/FEDER) and FPI postgraduate research grant (BES-2013-064415). The authors thank Dr Stephen Clark for fabrication of the microfluidic devices

Standardization of a galactogogue herbal mixture based on its total phenol and flavonol contents and antioxidant activity

Background and objectives: Dairy companies always try to increase the quantity and quality of milk production. According to the positive impact of different plants on milk production of cattle, this study was carried out to standardize a galactogogue herbal mixture based on its total phenol and flavonol contents and antioxidant activity.  Methods: A mixture of Galega officinalis L. and Nigella sativa L. powders (4:1 w/w), which had shown milk stimulating activity on Holstein cows in a previous study, was extracted with hydro alcoholic solvent (80% aq. methanol) and its 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity and total phenol and total flavonol contents were measured according to standard methods. Results: The inhibition concentration 50% (IC50 ) value of radical scavenging activity in DPPH test and the total phenol and total flavonol contents were found to be 154.29 µg/mL, 77.720±0.104 µg of gallic acid equivalent (GAE) and 0.231±0.018 µg of quercetin equivalent (QE) per mg of dry extract, respectively. Conclusion: This herbal extract can be standardized based on its antioxidant activity or total phenol and total flavonol contents and the standardized extract can be formulated as a veterinary galactogogue supplement

Standardization of a galactogogue herbal mixture based on its total phenol and flavonol contents and antioxidant activity

Abstract Background and objectives: Dairy companies always try to increase the quantity and quality of milk production. According to the positive impact of different plants on milk production of cattle, this study was carried out to standardize a galactogogue herbal mixture based on its total phenol and flavonol contents and antioxidant activity. Methods: A mixture of Galega officinalis L. and Nigella sativa L. powders (4:1 w/w), which had shown milk stimulating activity on Holstein cows in a previous study, was extracted with hydro alcoholic solvent (80% aq. methanol) and its 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity and total phenol and total flavonol contents were measured according to standard methods. Results: The inhibition concentration 50% (IC 50 ) value of radical scavenging activity in DPPH test and the total phenol and total flavonol contents were found to be 154.29 µg/mL, 77.720±0.104 µg of gallic acid equivalent (GAE) and 0.231±0.018 µg of quercetin equivalent (QE) per mg of dry extract, respectively. Conclusion: This herbal extract can be standardized based on its antioxidant activity or total phenol and total flavonol contents and the standardized extract can be formulated as a veterinary galactogogue supplement