Biosynthesis of Gold Nanoparticles and Its Effect against Pseudomonas aeruginosa

Antimicrobial resistance has posed a serious health concern worldwide, which is mainly due to the excessive use of antibiotics. In this study, gold nanoparticles synthesized from the plant Tinospora cordifolia were used against multidrug-resistant Pseudomonas aeruginosa. The active components involved in the reduction and stabilization of gold nanoparticles were revealed by gas chromatography–mass spectrophotometry(GC-MS) of the stem extract of Tinospora cordifolia. Gold nanoparticles (TG-AuNPs) were effective against P. aeruginosa at different concentrations (50,100, and 150 µg/mL). TG-AuNPs effectively reduced the pyocyanin level by 63.1% in PAO1 and by 68.7% in clinical isolates at 150 µg/mL; similarly, swarming and swimming motilities decreased by 53.1% and 53.8% for PAO1 and 66.6% and 52.8% in clinical isolates, respectively. Biofilm production was also reduced, and at a maximum concentration of 150 µg/mL of TG-AuNPs a 59.09% reduction inPAO1 and 64.7% reduction in clinical isolates were observed. Lower concentrations of TG-AuNPs (100 and 50 µg/mL) also reduced the pyocyanin, biofilm, swarming, and swimming. Phenotypically, the downregulation of exopolysaccharide secretion from P. aeruginosa due to TG-AuNPs was observed on Congo red agar plates     

A technique for obtaining true approximations for k-center with covering constraints

Mathematical Programming - There has been a recent surge of interest in incorporating fairness aspects into classical clustering problems. Two recently introduced variants of the k-Center problem...     

Comparison of Li+‐ion conductivity in linear and crosslinked poly(ethylene oxide)

Polymer electrolytes are of tremendous importance for applications in modern lithium‐ion (Li⁺‐ion) batteries due to their satisfactory ion conductivity, low toxicity, reduced flammability, as well as good mechanical and thermal stability. In this study, the Li⁺‐ion conductivity of well‐defined poly(ethylene oxide) (PEO) networks synthesized via copper(I)‐catalyzed azide–alkyne cycloaddition is investigated by electrochemical impedance spectroscopy after addition of different lithium salts. The ion conductivity of the network electrolytes increases with increasing molar mass of the PEO chains between the junction points which is completely opposite to the behavior of their respective uncrosslinked linear precursors. Obviously, this effect is directly related to the segmental mobility of the PEO chains. Furthermore, the ion conductivity of the network electrolytes under investigation increases also with increasing size of the anion of the added lithium salt due to a weaker anti‐plasticizing effect of the more bulky anions. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 21–28     

Design and validation of a nonlinear vibration absorber to attenuate torsional oscillations of propulsion systems

Nonlinear Dynamics - Recent developments in propulsion systems to improve energy efficiency and reduce hazardous emissions often lead to severe torsional oscillations and aggravated noise....     

Influence of organic dyes on the thermal,mechanical, and optical properties of l-arginine trifluoroacetate (LATF) single crystals

Bulk single crystals of pure and organic dyes (rhodamine, amaranth, and methyl orange) admixture l-arginine trifluoroacetate were grown by slow evaporation technique. The cell parameters and crystallinity of pure and dyes-mixed LATF were confirmed by powder X-ray diffraction analysis. Thermal analysis (TG/DTA, DSC) reveals the purity of the sample and no decomposition is observed up to melting point. In the TG trace of pure LATF, methyl orange: LATF, amaranth: LATF and rhodamine: LATF it is observed that the crystals were thermally stable up to 488, 485, 483, and 484.14 K, respectively. The crystals are further characterized using UV–Vis analysis, microhardness analysis, and EDAX analysis. By plotting log P versus log d, the value of the work hardening coefficient "n" was found to be 1.95, 0.52, 0.8, and 0.88 for pure, methyl orange, amaranth, and rhodamine dyes-doped LATF grown crystals, respectively. Second harmonic generation efficiency of pure and dye admixture LATF crystals was measured using Kurtz and Perry powder test, the efficiency of methyl orange, amaranth, and rhodamine dyes-doped LATF crystal is 2.7, 2.6, and 2.07 times greater than KDP, where as the efficiency of LATF pure is 2.5 times greater than that of KDP.