Review on Carbon Dioxide Utilization for Cycloaddition of Epoxides by Ionic Liquid-Modified Hybrid Catalysts: Effect of Influential Parameters and Mechanisms Insight

The storage, utilization, and control of the greenhouse (CO2) gas is a topic of interest for researchers in academia and society. The present review article is dedicating to cover the overall role of ionic liquid-modified hybrid materials in cycloaddition reactions. Special emphasis is on the synthesis of various cyclic carbonate using ionic liquid-based modified catalysts. Catalytic activity studies have discussed with respect to process conditions and their effects on conversion and product selectivity for the reaction of cycloaddition of CO2 with styrene oxide. The reaction temperature and the partial pressure of CO2 have found to play a key role in cyclic carbonate formation. The role of other influential parameter (solvent effect) is also discussed for the conversion of cyclic/aromatic oxides to polycarbonate production. Our own research work that deals with ionic liquid-based halide-modified mesoporous catalyst (MCM-41 type) derived from rice husk waste has also been discussed. Finally, the role of carbon dioxide activation and ring-opening mechanisms involved in the cyclic carbonate product formation from CO2 have been discussed

Topical antifungal keratitis therapeutic potential of Clitoria ternatea Linn. flower extract: phytochemical profiling, in silico modelling, and in vitro biological activity assessment

IntroductionFungal keratitis (FK) poses a severe threat to vision, potentially leading to blindness if not promptly addressed. Clitoria ternatea flower extracts have a history of use in Ayurvedic and Indian traditional medicines, particularly for treating eye ailments. This study investigates the antifungal and antibiofilm effects of Clitoria ternatea flower extracts on the FK clinical isolate Coniochaeta hoffmannii. Structural details and key compound identification were analysed through FTIR and GC-MS.MethodsThe minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of Clitoria ternatea flower extracts were determined using broth dilution and well plate techniques. Biofilm inhibitory activity was assessed through microscopic evaluation, while anti-irritant and cytotoxic properties were evaluated using CAE-EI and MTT assays. Through GC-MS and FT-IR analysis the compounds dissolved in the extract and their functional group were studied, and their toxicity screening and pharmacokinetic prediction were conducted in silico. Subsequently, compounds with high corneal permeability were further identified, and molecular docking and simulation studies at 150 ns were used to investigate their interactions with fungal virulence factors and human inflammatory proteins.Results and DiscussionAt a concentration of 250 µg/mL, the Clitoria ternatea flower extract displayed effective biofilm inhibition. MIC and MFC values were determined as 500 and 1000 µg/mL, respectively. CAE-EI and MTT assays indicated no significant irritant and cytotoxic effects up to a concentration of 3 mg/mL. Compounds like 9,9-dimethoxybicyclo[3.3.1]nonane-2,4-dione showed high corneal permeability with strong and stable interactions with fungal virulence cellobiose dehydrogenase, endo β 1,4 xylanase, and glucanase, as well as corneal inflammation-associated human TNF-α and Interleukin IL-1b protein targets. The findings indicate that extracts from C. ternatea flowers could be formulated for an effective and safe alternative for developing new topical FK therapeutics

Multicomponent Domino Synthesis, Anticancer Activity and Molecular Modeling Simulation of Complex Dispirooxindolopyrrolidines

A series of spirooxindolopyrrolidine fused N -styrylpiperidone heterocyclic hybrids has been synthesized in excellent yield via a domino multicomponent protocol that involves one-pot three component 1,3-dipolar cycloaddition and concomitant enamine reactions performed in an inexpensive ionic liquid, namely 1-butyl-3-methylimidazolium bromide ([bmim]Br). Compounds thus synthesized were evaluated for their cytotoxicity against U-937 tumor cells. Interestingly; compounds 5i and 5m exhibited a better cytotoxicity than the anticancer drug bleomycin. In ddition; the effect of the synthesized compounds on the nuclear morphology of U937 FaDu cells revealed that treatment with compounds 5a–m led to their apoptotic cell death

Effect of Different Gamma Dose and Chemical Etching on Pre- and Post-Alpha-Irradiated PM-355 Polymer

This work is based on the effect of different gamma doses with pre- and post-alpha-irradiated PM-355 polymer (polycarbonate of allyl diglycol). The phase crystallinity and structural analysis of the reference and irradiated PM-355 polymer were analyzed using an X-ray diffraction (XRD) study. It is revealed that the irradiation and etching reduce the %crystallinity but increase the crystallite size of the PM-355 polymer. The increase in crystallite size of PM-355 polymer after irradiation is supported by the scanning electron microscopic (SEM) analysis. The etching of the samples results in an increase in its track diameter. The optical band gap energy, measured by ultraviolet-visible (UV-VIS) spectroscopy, shows a decrement trend with the increase of gamma and alpha irradiation doses, and etching for all sets of samples under investigation. The number of carbon atoms per conjugation and per cluster has increased after gamma irradiation and etching. However, the increment is more pronounced for etched samples compared to nonetched ones. This indicates that etching results in a bigger size of cluster. Photoluminescence (PL) for both cases before and after etching has a dominant peak around 430 nm before and after irradiation, and change in peak intensity after irradiation confirmed that particle bombardment induced defects and clusters in the PM-355, which serves as nonradiative centers. The polymer can be used as a detector for gamma irradiation

The antimicrobial activity of silver nanoparticles biocomposite films depends on the silver ions release behaviour

This study aimed to investigate the release of silver ions from the packaging, their diffusion within a food hydrogel and the effect on the growth of Pseudomonas fluorescens. Biosorbed-silver nanoparticles (BSNPs) were synthesized using a plant extract and were incorporated into chitosan or poly (vinyl alcohol) polymer to prepare biocomposite films. The addition of BSNPs improved the physical and antimicrobial properties of the films as shown by tensile strength and inhibition of P. fluorescens in hydrogels, respectively. PVA based BSNPs film showed a stronger antimicrobial effect, compared to chitosan based BSNPs film and this correlated with a higher amount of silver ions release from the PVA film into the hydrogel. Results suggest that the strength of the interaction between BSNPs and the film polymer is the key factor leading to the difference in the release behaviour of the antimicrobials, which in turn determines the antimicrobial activity of the active packaging

Recycling and Reusing Polyethylene Waste as Antistatic and Electromagnetic Interference Shielding Materials

The aim of this work is to manage the waste product based on polyethylene (PE) films by recycling and reusing it as antistatic material for electronic packaging and electromagnetic interference (EMI) shielding material for protecting electronic equipment from interference of EM radiation. To achieve this, a conductive carbon black has been mixed with the PE waste at different weight percent values by ultrasonication via a solution mixing process. Mixing time for sonication was determined by ultraviolet-visible (UV-VIS) spectra. A differential scanning calorimetry (DSC) study showed that the low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) are immiscible in their blend composition. The tensile properties of PE have reduced substantially after reprocessing. However, the addition of carbon black has improved its strength up to a certain loading. The electrical percolation threshold values, calculated using the classical power law and sigmoidal Boltzmann model, were obtained at 3.5 and 2.8 wt% loading of carbon black, respectively. The conductivity result revealed that 1-2 wt% carbon-loaded composites can be used as antistatic material. The composites, having carbon loading above 4 wt%, can be effective materials for EMI shielding application. The 10 wt% carbon-loaded composite exhibits EMI SE value 33 dB which means there is approximately 99.93% protection of EM radiation at the sample thickness of 1.0 mm. Moreover, FTIR analysis, thermal stability, AC conductivity, dielectric properties, permeability, and current-voltage characteristics are also discussed in detail. There is a substantial increment in thermal stability, and dielectric properties are observed with the addition carbon black loading within the polymer matrix

Efficiency Improvement of a Capacitive Deionization (CDI) System by Modifying 3D SWCNT/RVC Electrodes Using Microwave-Irradiated Graphene Oxide (mwGO) for Effective Desalination

This work is aimed at improving the electrosorption capacity of carbon nanotube/reticulated vitreous carbon- (CNT/RVC-) based 3D electrodes and decreasing the duration of electrosorption-desorption cycles by facilitating the ions’ adsorption and desorption on the electrode surface. This was achieved by preparing composites of microwave-irradiated graphene oxide (mwGO) with CNT. All composite materials were coated on RVC by the dip-coating method. The highest loading level was 50 mg. This is because it exhibited the maximum electrosorption capacity when tested in terms of geometric volume. The results showed that the 9-CNT/mwGO/RVC electrode exhibited 100% capacitive deionization (CDI) cyclic stability within its 1st five cycles. Moreover, 27.78% time was saved for one adsorption-desorption cycle using this electrode compared to the CNT/RVC electrode. In addition, the ion removal capacity of NaCl by the 9-CNT/mwGO/RVC electrode with respect to the mass of the electrode (3.82 mg/g) has increased by 18.27% compared to the CNT/RVC electrode (3.23 mg/g) when measured at the optimum conditions. In a complete desalination process, the water production per day for the 9-CNT/mwGO/RVC electrode was increased by 67.78% compared to the CNT/RVC electrode when measured within the same CDI cell using NaCl solution of concentration less than 1 mg/L. When considered volume of 1 m3, this optimum 9-CNT/mwGO/RVC electrode produces water 29,958 L per day. The highest electrosorption capacity, when measured experimentally at 500 mg/L NaCl feed concentration, was 10.84 mg/g for this optimum electrode, whereas Langmuir isotherm gave the theoretically calculated highest value as 16.59 mg/g. The results for the 9-CNT/mwGO/RVC composite electrode demonstrate that it can be an important electrode material for desalination in CDI technology

Influence of Biopolymer Carrageenan and Glycerine on the Properties of Extrusion Printed Inks of Carbon Nanotubes

This article focuses on the preparation of extrusion printing composite inks of multiwall carbon nanotube (MWNT) dispersed separately in iota-carrageenan (IC) and glycerine (G) solution. Both composites (IC-MWNT and G-MWNT) showed shear-thinning behavior when their flow characteristics were tested. Conductive solid tracks/patterns of both printed composite inks were deposited on glass slide, PET (polyethylene terephthalate) sheet, and IC gel films substrates. The conductive patterns were characterized with microscopy, scanning electron microscopy (SEM), and profilometer. Moreover, their contact angle and electrical conductivity were measured. Profilometry showed that increased number of extruded layers gave increased cross-sectional area. SEM study showed that printing ink is embedded into the surface of IC film, discontinuous on glass slide and smoother on PET sheet. Conductivity of IC-MWNT track was 9 ± 1 S/m and that of G-MWNT was 2942 ± 84 S/m on glass substrate of one layer thick. This is because fewer carbon nanotubes (CNT) are present in G-MWNT track as confirmed by SEM study. The nature of substrate also affects the conductivity of printed patterns. The impressive result of conductivity of printed patterns of composite inks can make them useful for bioelectronic application

Review on Carbon Nanotube Varieties for Healthcare Application: Effect of Preparation Methods and Mechanism Insight

Many potential uses of carbon nanotubes (CNT) in various sectors have created an urge to assess their diverse range of properties pertaining to various applications like catalysis, biosensor, and antimicrobial activity. Increasing studies on the biosensor and antibacterial activity of CNT have prompted tremendous interest in the utilization of the carbon-based nanostructured material as an alternative to currently existing antibiotics. However, the study of bactericidal aspects of this nanomaterial is relatively new and hence the deeper understanding of the various physicochemical characteristics and antimicrobial nature of CNT is extremely wanted. This review covers the effect of framework substitution and explains the understanding of membrane disintegration and oxidative stresses upon nanomaterials for antimicrobial activity. The present article has also reviewed effect of preparation nanoparticle deposition and framework modification on carbon nanotube structure. The recent research on graphene-modified nanomaterials for biosensor applications related to healthcare/clinical applications have also been discussed. Major physicochemical contributing factors such as size, functionalization, high surface area, and aggregation features of CNT assisting in the bacterial killing have nicely been outlined. Hence, the present review explains the supporting information related with Single and multi-walled carbon nanotube and summarized the advantages of functionalized carbon nanotube/graphene-based nanostructured carbon-based materials towards protection and reduction of bacterial/viral infections in the healthcare sector