Enhanced antibacterial activity of streptomycin against some human pathogens using green synthesized silver nanoparticles

AbstractThe development of eco-friendly technologies in nanoparticle synthesis is of utmost importance in order to expand their biological horizons. In the present study, bioreduction of AgNO3 into AgNPs using various leaf extracts of Ficus virens is explained. The resulting AgNPs were characterized by UV–vis spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Synthesis of AgNPs was confirmed by color change from transparent to brown with maximum absorption at 420 nm due to surface plasmon resonance of AgNPs. X-ray diffraction studies showed that the biosynthesized AgNPs were crystalline in nature, and TEM analysis showed spherical shape of the nanoparticles with size ranging from 4.98 to 29 nm. FTIR study indicates that mainly –C = O, -OH and N-H groups in leaf extracts are involved in the reduction of Ag+ ions to Ag atoms, and proteins are responsible for stabilizing the silver nanoparticles. The synthesized AgNPs showed significant antibacterial activity against Gram positive and gram negative human bacterial pathogens. The results showed that AgNPs also synergistically enhance (2.02–57.98%) the antibacterial activity of streptomycin, a common antibiotic. With this approach, AgNPs can be used as a new generation of antimicrobial agents for successful development of drug delivery

Effect of process parameters on properties of polypropylene and kenaf fibres needle-punched nonwoven geotextiles

Effects of stroke frequency, depth of needle penetration and mass per unit area on properties of needle-punched nonwoven fabrics produced from polypropylene (PP), 50/50 PP/kenaf and kenaf fibres have been studied. Properties of fabrics, such as tensile strength, puncture resistance, pore size, water permeability and transmissivity are analysed. Results obtained show that the higher tensile strength and puncture resistance are achieved in fabrics produced from kenaf fibres at higher stroke frequency, depth of needle penetration and mass per unit area. Fabrics produced from kenaf fibres can be employed in geotextile applications, since they also possess bigger pore size and higher water permeability.

Effect of process parameters on properties of polypropylene and kenaf fibres needle-punched nonwoven geotextiles

274-285Effects of stroke frequency, depth of needle penetration and mass per unit area on properties of needle-punched nonwoven fabrics produced from polypropylene (PP), 50/50 PP/kenaf and kenaf fibres have been studied. Properties of fabrics, such as tensile strength, puncture resistance, pore size, water permeability and transmissivity are analysed. Results obtained show that the higher tensile strength and puncture resistance are achieved in fabrics produced from kenaf fibres at higher stroke frequency, depth of needle penetration and mass per unit area. Fabrics produced from kenaf fibres can be employed in geotextile applications, since they also possess bigger pore size and higher water permeability

Development of thermoresponsive poly(propylene-g-N-isopropylacrylamide) non-woven 3D scaffold for smart cell culture using oxyfluorination-assisted graft polymerisation

Growing cells on 3D scaffolds is far superior to the conventional 2D monolayer culture method. In this study, a novel 3D thermoresponsive poly(propylene-g-N-isopropylacrylamide) (PP-g-PNIPAAm) nonwoven fabric (gNWF) was developed for cell culture using oxyfluorination-assisted graft polymerisation (OAGP). New polar functional groups were detected on the oxyfluorinated NWF (oNWF), and PNIPAAm was confirmed in the gNWF by attentuated total-reflectance Fourier transform infrared (ATR-FTIR) and scanning X-ray photoelectron spectroscopy (S-XPS). Scanning electron microscopy (SEM) revealed a rough surface morphology and confinement of the PNIPAAm graft layer to the surface of the fibres in the gNWF. The OAGP method did not affect the crystalline phase of bulk PP, however, twin-melting thermal peaks were detected for the oNWF and gNWF indicating crystal defects. Contact angle studies showed that the surface of the gNWF exhibited a thermoresponsive behaviour. Hepatocyte cells attached onto gNWF disks in a bioreactor at 37 ◦C and remained viable for 10 days in culture. Upon cooling the cell culture media to 20 ◦C, cells were spontaneously released as 3D multi-cellular constructs without requiring destructive enzymes. The development of 3D thermoresponsive scaffolds capable of non-invasive 3D cell culture could provide a more reliable in vitro model for cells.http://www.elsevier.com/locate/colsurfahb201

Screening of anti-dengue activity in methanolic extracts of medicinal plants

<p>Abstract</p> <p>Background</p> <p>Dengue fever regardless of its serotypes has been the most prevalent arthropod-borne viral diseases among the world population. The development of a dengue vaccine is complicated by the antibody-dependent enhancement effect. Thus, the development of a plant-based antiviral preparation promises a more potential alternative in combating dengue disease.</p> <p>Methods</p> <p>Present studies investigated the antiviral effects of standardised methanolic extracts of <it>Andrographis paniculata, Citrus limon, Cymbopogon citratus, Momordica charantia, Ocimum sanctum </it>and <it>Pelargonium citrosum </it>on dengue virus serotype 1 (DENV-1).</p> <p>Results</p> <p><it>O. sanctum </it>contained 88.6% of total flavonoids content, an amount that was the highest among all the six plants tested while the least was detected in <it>M. charantia</it>. In this study, the maximum non-toxic dose (MNTD) of the six medicinal plants was determined by testing the methanolic extracts against Vero E6 cells <it>in vitro</it>. Studies also determined that the MNTD of methanolic extract was in the decreasing order of <it>M. charantia </it>><it>C. limon </it>><it>P. citrosum, O. sanctum </it>><it>A. paniculata </it>><it>C. citratus</it>. Antiviral assay based on cytopathic effects (CPE) denoted by degree of inhibition upon treating DENV1-infected Vero E6 cells with MNTD of six medicinal plants showed that <it>A. paniculata </it>has the most antiviral inhibitory effects followed by <it>M. charantia</it>. These results were further verified with an <it>in vitro </it>inhibition assay using MTT, in which 113.0% and 98.0% of cell viability were recorded as opposed to 44.6% in DENV-1 infected cells. Although methanolic extracts of <it>O. sanctum </it>and <it>C. citratus </it>showed slight inhibition effect based on CPE, a significant inhibition was not reflected in MTT assay. Methanolic extracts of <it>C. limon </it>and <it>P. citrosum </it>did not prevent cytopathic effects or cell death from DENV-1.</p> <p>Conclusions</p> <p>The methanol extracts of <it>A. paniculata </it>and <it>M. charantia </it>possess the ability of inhibiting the activity of DENV-1 in <it>in vitro </it>assays. Both of these plants are worth to be further investigated and might be advantageous as an alternative for dengue treatment.</p

Large-scale extension of woven fabrics

SIGLEAvailable from British Library Document Supply Centre- DSC:D77435 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Studies on Enhancement of Mechanical Properties and Interfacial Adhesion of Flax Reinforced Polypropylene Composites

Natural fibre is often used as reinforcement in polymer composites. The main problem of using these natural fibres is their poor compatibility and hydrophilic nature. Therefore, chemical modification of constituents becomes necessary to enhance adhesion between hydrophilic fibre and hydrophobic polymer matrix. The aim of this work is to improve the interfacial adhesion between the polypropylene matrix and the nonwoven flax batting. Chemical treatments with acrylic acid, 4-pentanoic acid, 2,4-pentadienoic acid, and 2-methyl-4-pentanoic acid were investigated. The composites were processed by compression molding using a film stack method. The mechanical properties of these modified composites, such as tensile, flexural, and impact strength were analyzed and compared. It was found that these properties were dependent on the kind and amount of chemical treatment. SEM and thermal studies were also conducted. </jats:p