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Synthesis of silver nanoparticles by aqueous extract of Zingiber officinale and their antibacterial activities against selected species

Hussain Zawar, Jahangeer Muhammad, ur Rahman Shafiq, Ihsan Tamanna, Sarwar Abid, Ullah Najeeb, Aziz Tariq, Alharbi Metab, Alshammari Abdulrahman, Alasmari Abdullah F.

Polish Journal of Chemical Technology

2023

Vol. 25, nr 3

23--30

Silver nanoparticles have special plasmonic and antibacterial characteristics that make them efficient in a variety of commercial medical applications. According to recent research, chemically synthesized silver nanoparticles are harmful even in low concentrations. It was crucial to identify appropriate synthesis methods that may have low costs and be nontoxic to the environment. Zingiber officinale (ginger) extracts used to prepare silver nanoparticles were inexpensive and environmentally friendly, and the best physicochemical characteristics were analyzed. Silver nanoparticles were characterized by using UV-visible spectroscopy, Scanning electron microscopy (SEM), and X-ray diffraction (XRD). The surface Plasmon resonance peak at 425 nm was observed using UV-Visible spectroscopy. Scanning electron microscopy observed that the nanoparticles were spherical and ranged in size from 5 to 35 nm. The XRD pattern values of 2θ: 38.2° , 46.3° , and 64.58° are used to determine the planes (111), (200), and (220). The silver nanoparticle’s existence was verified by the face-centered cubic (FCC). Silver nanoparticles were found to have antibacterial efficacy against gram-positive Staphylococcus and gram-negative bacteria such as Pseudomonas aeruginosa, Klebsiella Aerogenes, Salmonella, Staphylococcus and Escherichia coli. The antibacterial activity of silver nanoparticles was observed using the agar well diffusion (AWD) method at three different concentrations (100 μg/ ml, 75 μg/ml, and 50 μg/ml). The zone of inhibition measured against the bacterial strains pseudomonas Aeruginosa, Klebsiella aerogenes, Escherichia coli, Salmonella and Staphylococcus which were (18.4±1.25 mm, 16.9±0.74 mm, 14.8±1.25 mm), (16.8±0.96 mm, 14.6±0.76 mm, 14.0±1.15 mm), (19.7±0.76 mm, 18.2±0.66 mm, 15.4±1.15 mm), (16.6±0.67 mm, 14.2±0.23 mm, 12.8±0.78 mm) and (12±0.68 mm, 10±0.20 mm, 08±0.15 mm). These nanoparticles’ potent antibacterial properties may enable them to be employed as nanomedicines for a variety of gramnegative bacterial illness treatments.

Mycoremediation of Heavy Metals Contaminated Soil by Using Indigenous Metallotolerant Fungi

Akram Muhammad Bilal, Khan Ibrar, Ur Rehman Mujaddad, Sarwar Abid, Ullah Najeeb, ur Rahman Shafiq, Aziz Tariq, Alharbi Metab, Alshammari Abdulrahman, Alasmari Abdullah F.

Polish Journal of Chemical Technology

2023

Vol. 25, nr 3

1--13

The present study was aimed to identify the indigenous fungal strains which could possibly be applied to the bioremediation of heavy metal-contaminated soil. The contaminated soil samples of Korangi Industrial Estate Karachi were found to have total concentration of Cu 1.044 mgL1 , and Pb 0.631 mgL–1. A total of eight indigenous strains of the fungus were isolated and screened for bioremediation capacity from heavy metals-contaminated soil. For the bioremediation of Lead (Pb) these same indigenous eight fungal strains were used for biological remediation. All the fungal isolated with enhanced bioremediation capability were through phenotypic and genotypical characterization. The topology of the phylograms established that the fungal isolates used in this study were allocated to: K1 (Penicillium notatum), K2 (Aspergillus parasiticus), K3 (Aspergillus fumigatus), K4 (Aspergillus flavus), K5 (Aspergillus terries), K6 (Fusarium solani), K7 (Penicillium chrysogenum), K8 (Aspergillus niger), K9 (Penicillium piceum) and K10 (Penicillium restrictum). Thus, K8 fungal isolate was found to be more efficient with maximum bioremediation capacity, for copper and lead removal efficiency, and selected for FTIR and SEM to find out the uptake of Cu and Pb which of the functional groups are involved, and further to detect the effects of bioleaching of both heavy metals on to the surface of K8 fungus biomass. The current study indicates that indigenous fungal isolates could be used with high potency to remediate or clean up the heavy metals-contaminated soil either by the technique of in situ or ex-situ bioremediation.

Dynamic modeling and parametric analysis of differential gearbox used in electric vehicle

Ullah Najeeb, Song Chaosheng, Zhu Caichao, Ou Zhuxiang, Tan Cong

Journal of Theoretical and Applied Mechanics

2020

Vol. 58 nr 1

73--85

The aim of this study is to perform the modeling and parametric analysis of dynamic mesh force in the light of resonance modes. Firstly, dynamic modeling of a differential gearbox has been performed by using the lumped parameter method. Then, the resonant points from Campbell diagrams were studied for the first three critical harmonic orders. Furthermore, two case studies were proposed in order to investigate the impact of radial clearance and face width on the dynamic mesh force along with resonance. Simultaneously, resonance identification and elimination were studied for two working conditions. Results show that the influence of lowering face width of pinions is more effective on mesh force reduction and resonance elimination as opposed to the first case study by enhancing wheel side mesh stiffness.