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Molecular Simulation Prediction on SO2 Gas Adsorption in Bipyridine Ligand-Based Square-Pillared MOFs
Increasing concentrations of toxic gases caused by the burning of fossil fuels necessitates the development of efficient porous materials for gas capture. Metal-organic frameworks (MOFs) have attracted a lot of attention as potential porous materials due to their effectiveness in adsorption of toxic gases. In particular, square-pillared metal-organic frameworks stand out for their exceptional potential toward gas adsorption, attributed to their remarkable surface area, thermal and chemical stabilities, and tunable properties. In this context, molecular simulations have been executed to observe and analyze the adsorption process of toxic flue gases such as SO2 and CO2 on MOFs. The present work deals with two different stable fluorinated MOFs named [Ni(4,4?-bipyridine)2(AlF5)]n (ALFFIVE-Ni-bipy) and [Ni(4,4?-bipyridine)2(NbOF5)]n, (NBOFFIVE-Ni-bipy) featuring AlF52- and NbOF52- anion pillars, respectively, comprising 4,4?-bipyridine as organic ligand and nickel as the central metal. The significance of utilizing the 4,4?-bipyridine ligands in these fluorinated MOFs enhances the SO2 gas adsorption and selectivity in the framework. Density functional theory has been implemented for geometry optimization, and Grand Canonical Monte Carlo simulations have been performed to forecast the adsorption isotherms. Both ALFFIVE-Ni-bipy (11.4 mmol/g) and NBOFFIVE-Ni-bipy (8.7 mmol/g) showed high SO2 adsorption capacity at 1 bar pressure, but ALFFIVE-Ni-bipy showed very good adsorption than other square-pillared MOFs and also unveiled good selectivity of SO2 gas. The coadsorption of binary SO2/CO2 and ternary SO2/CO2/N2 gas mixtures at ambient conditions indicated that the cost-effective aluminum (Al)-based square-pillared ALFFIVE-Ni-bipy is particularly suitable for acid gas adsorption. 2024 American Chemical Society -
Molecular phylogenetics and character evolution in Haplanthodes (Acanthaceae), an endemic genus from peninsular India
Haplanthodes (Acanthaceae) is an Indian endemic genus with four species. It is closely related to Andrographis which is also mainly distributed in India. Haplanthodes differs from Andrographis by the presence of cladodes in the inflorescences, subactinomorphic flowers, stamens included within the corolla tube, pouched stamens and oblate pollen grains. To understand the phylogenetic relationship of Haplanthodes, Andrographis and Haplanthus, which are putatively closely related taxa, we used four plastid markers, matK, rbcL, psbA-trnH and trnGRto construct a molecular phylogeny. Our results established the monophyly of Haplanthodes and revealed a sister relationship to Andrographis and Haplanthus. Further, to understand the historical biogeography of the genus, we inferred the divergence time and performed an ancestral area reconstruction. Our analyses suggest that Haplanthodes evolved during Late Miocene 5.85 Ma (95%HPD: 2.1810.34 Ma) in peninsular India where it might have shared a common ancestor with Andrographis. To understand character evolution, the ancestral states of important morphological characters were inferred and discussed based on the equal rate model. The generic status of Haplanthus was not resolved due to incomplete sampling. 2022 Nordic Society Oikos. Published by John Wiley & Sons Ltd. -
Molecular level investigation on the impact of geometric isomers as fluorinated ligands in SIFSIX MOF for natural gas sweetening
In natural gas (NG), significant amounts of hydrogen sulfide (H2S) and carbon dioxide (CO2) are the most menacing contaminants that cause degradation of the purity of fuel. We considered fluorine-functionalized MOFs and employed cheaper and faster computational simulation techniques to understand the adsorption process. Hence, this includes structural optimization of newly designed fluorine-functionalized MOF with Density Functional Theory (DFT) and further Grand Canonical Monte Carlo (GCMC) simulation at room temperature on those MOFs for understanding in detail the adsorptive separation process on sour gases. However, the main emphasis has been made on the adsorptive separation of H2S gas from sour gas. Eventually, the fluorination of organic ligand in [(SiF6)Ni(1,2-di(pyridin-4-yl)ethyne)2] MOF has resulted in an excellent H2S/CO2 separation performance from NG because of the different geometrical isomers. The cis isomer of 1,2-di(pyridin-4-yl)ethyne as ligand in MOF, i.e., SIFSIX-Ni-dpe-3-cis, shows a high CO2 affinity than H2S; on the contrary, the trans isomer of 1,2-di(pyridin-4-yl)ethyne as ligand in MOF, i.e., SIFSIX-Ni-dpe-3-trans, has H2S selective over CO2 and CH4. So, the resulting affinity variation indicates that structural variation by the stereochemistry of ligands in MOF plays a significant role in NG purification, which is further validated through detailed molecular simulation analysis. 2022 Taylor & Francis Group, LLC. -
Molecular docking study, and ADMET analysis for the synthesized novel Zn(II) complexes as potential SARS-CoV-2 inhibitors
A new SARS-CoV-2 virus and its variants including omicron created a pandemic situation and caused more deaths in worldwide prompted many researchers to explore potential drug candidates. In this connection, we explored the first-of-its-kind report on computational studies such as molecular docking, and ADMET properties of Zn(II) complexes. The studies revealed the novel zinc complexes have high binding affinities with the SARS-CoV-2 spike glycoprotein (6vxx) alpha variant (7EKF), beta variant (7ekg), gamma variant (7EKC), delta variant (7V8B), and the omicron variant (7T9J). Molecular docking results of RMSD for SARS-CoV-2 beta variant (7ekg) and gamma variant (7EKC) are within excellent chemical stability in their protein-ligand complex state and should be effective in the biological system. ADME studies provided the better results with no adverse effect of toxicity related AMES along with absence of hepatotoxicity and skin sensitization when compared to Molnupiravir drug and it has a greater hepatotoxicity. This study could open further exploration of these novel zinc complexes for SARS-CoV-2 inhibition. (2024) DergiPark. -
Molecular detection of Kudoa septempunctata (Myxozoa: Multivalvulida) in sea water and marine invertebrates
The exportation of cultured olive flounder (Paralichthys olivaceus) in Korea has been recently decreasing due to the infections with a myxozoan parasite Kudoa septempunctata, and there is a strong demand for strict food safety management because the food poisoning associated with consumption of raw olive flounder harbouring K. septempunctata has been frequently reported in Japan. The life cycle and infection dynamics of K. septempunctata in aquatic environment are currently unknown, which hamper establishment of effective control methods. We investigated sea water and marine invertebrates collected from olive flounder farms for detecting K. septempunctata by DNA-based analysis, to elucidate infection dynamics of K. septempunctata in aquaculture farms. In addition, live marine polychaetes were collected and maintained in well plates to find any possible actinosporean state of K. septempunctata. The level of K. septempunctata DNA in rearing water fluctuated during the sampling period but the DNA was not detected in summer (June-July in farm A and August in farm B). K. septempunctata DNA was also detected in the polychaetes Naineris laevigata intestinal samples, showing decreased pattern of 40 to 0%. No actinosporean stage of K. septempunctata was observed in the polychaetes by microscopy. The absence of K. septempunctata DNA in rearing water of fish farm and the polychaetes N. laevigata intestinal samples during late spring and early summer indicate that the infection may not occur during this period. N. laevigata was suspected as the possible alternate invertebrate host of K. septempunctata, but the actinosporean stage was not found by well plate method and further studies will be necessary. This research provides important baseline information for understanding the infection dynamics of K. septempunctata in olive flounder farms and further establishment of control strategies. 2017 The Author(s). -
Molecular architecture of PANI/V2O5/MnO2 composite designed for hydrogen evolution reaction
An ever increasing demand for energy has mandated scientists towards exploring innovative and environmentally friendly energy production techniques that can meet the needs of human beings and the world at large. Among the various techniques, hydrogen evolution reaction (HER) is a cost-effective and efficient method that produces hydrogen, a better fuel, for meeting our energy requirements. The large surface area, good redox capacity, high electroactivity, and tunable bandgap of polyaniline (PANI) makes it a preferred candidate for various energy-related applications. Incorporating mixed metal oxides into a polymer enhances its catalytic activities and can be used as an electrocatalyst for HER. In situ chemical oxidative polymerization method has been carried out to synthesize PANI/V2O5/MnO2 composite. The characterization studies of PANI/V2O5/MnO2 composite are done using XRD, FT-IR, BET, XPS, and FE-SEM analysis. The PANI/V2O5/MnO2 composite is used for linear sweep voltammetry studies and shows that it acts as an efficient electrocatalyst which gives an overpotential of 130 mV at 10 mA/cm2. The high electrocatalytic activity of the composite is due to the better surface phenomenon that is enhanced by the high porosity and surface area. The electrochemical impedance spectroscopy also shows lower charge transfer resistance for the PANI/V2O5/MnO2, confirming its excellent electroactivity. 90% of the current density is retained even after 7200 seconds, validating its stability. 2023 Elsevier B.V. -
Moisture-Sensitive Fe2O3 Nanoparticle-Based Magnetic Soft Actuators
Multifunctional soft robots are emerging as a new-generation intelligent device for challenging environments. To meet the requirements of smart applications and soft robotics, developing a soft actuator capable of multiple functions and mechanical deformation is essential. In this study, we designed a free-standing magnetic soft actuator constructed from iron oxide (Fe2O3) nanoparticles and poly(vinyl alcohol) (PVA), that responds to both moisture and magnetic fields. We used computational modeling (density functional theory and ab initio molecular dynamics) to explain the experimental findings demonstrating the deformation and high-bending angle (?150), which is about twice as large under combined moisture and magnetic field exposure compared to their individual effect. Additionally, a flower-shaped soft robot was designed by using the continuous bending deformation of the actuator in response to moisture changes, performing directional bending in an ambient environment. These findings demonstrate the materials sensitivity to moisture and magnetic fields, opening up new possibilities for designing responsive structures in the smart device industry. 2024 American Chemical Society. -
MOF derived cobalt-phospho-boride for rapid hydrogen generation via NaBH4 hydrolysis
Developing effective transition metal catalysts that can replace precious metal-based catalysts for hydrogen generation from the hydrolysis of chemical hydride has attracted extensive interest. This study focuses on synthesizing cobalt phospho-boride (CoPB) within a metal-organic framework (MOF) framework using hydrothermal and chemical reduction methodologies. Incorporating boron and phosphorous into Co-MOF enhances the hydrogen generation rate, reaching 1.8 L/min/g and 3.6 L/min/g for CoB-MOF and CoPB-MOF, respectively, during NaBH4 hydrolysis. Along with the nanostructured morphology of MOF, the electron modulation around Co-sites due to the presence of P and B creates a synergic effect to produce this high H2 generation rate and very low activation energy of 20.7 kJ/mol. The kinetic studies on NaBH4 hydrolysis reaction revealed zero-order kinetics with respect to NaBH4 concentration for CoPB-MOF, where porous morphology renders facile movement of BH4? ions to the active sites. The heat treatment at 773 K in the N2 atmosphere did not show any significant fall in the activity of CoPB-MOF, thus showcasing its robust nature. Moreover, the present catalyst also displayed recycling behavior with no signs of deactivation. 2024 Hydrogen Energy Publications LLC -
Modulated rayleigh-benard ferroconvection in couple stress fluid
Ferromagnetic fluid with couple stress confined between two stress-free, isothermal horizontal plates is considered in this study. The effect of different types of modulation on Rayleigh-Bard convection in a ferromagnetic fluid with couple stress is examined by considering sinusoidal (sine) and non-sinusoidal (square, triangular, and sawtooth) wave types of modulation. Rayleigh- Bard convection in a ferromagnetic fluid with couple stress subjected to gravity, rotation, temperature, and internal heat modulation is discussed by performing linear and non-linear analyses. The expression for the critical Rayleigh number and the correction Rayleigh number are deduced using the Venezian approach. The effect of gravity, rotation, temperature and internal heat modulation on heat transport is studied using the generalized Lorenz model. The effect of various parameters on the onset of convection and heat transport is studied. The ferromagnetic parameters hasten the convection onset and enhance the heat transfer under various modulations. The results of a Newtonian fluid, ferromagnetic fluid, and couple stress fluid is obtained as the limiting cases of this study. -
Modulated Rayleigh-benard ferroconvection in couple stress fluid
Ferromagnetic fluid with couple-stress confined between two stress-free, isothermal horizontal plates is considered in this study. The effect of different types of modulation on Rayleigh-Bénard convection in a ferromagnetic fluid with couple-stress is examined by considering sinusoidal (sine) and non-sinusoidal (square, triangular, and sawtooth) wave type of modulation. Rayleigh-Bénard convection in a ferromagnetic fluid with couple-stress subjected to gravity, rotation, temperature, and internal heat modulation is discussed by performing linear and non-linear analyses. The effect of various parameters on the onset of convection and heat transport is studied. The ferromagnetic parameters hasten the convection onset and enhance the heat transfer under various modulations. The results of a Newtonian fluid, ferromagnetic fluid, and couple-stress fluid are obtained as the limiting cases of this study. -
Modified Rice Husk Silica from Biowaste: An Efficient Catalyst for Transesterification of Diethyl Malonate and Benzyl Alcohol
Abstract: Molybdenum and lanthanum oxide modified silica-based catalysts were prepared from the agricultural waste rice husk. These synthesized catalysts were characterized by various spectroscopic and non-spectroscopic techniques. The catalytic performance was investigated by transesterification reaction between diethyl malonate and benzyl alcohol in the liquid phase using modified silica as a heterogeneous catalyst. Molybdenum modified silica-based catalyst showed the highest conversion efficiency of 95.6% and selectivity of 96.8% for dibenzyl malonate. The reaction conditions were optimized to give maximum efficiency with the highest selectivity in a solvent-free green method. Graphic Abstract: [Figure not available: see fulltext.]. 2019, Springer Nature B.V. -
Modified PredictorCorrector Method for the Numerical Solution of a Fractional-Order SIR Model with 2019-nCoV
In this paper, we analyzed and found the solution for a suitable nonlinear fractional dynamical system that describes coronavirus (2019-nCoV) using a novel computational method. A compartmental model with four compartments, namely, susceptible, infected, reported and unreported, was adopted and modified to a new model incorporating fractional operators. In particular, by using a modified predictorcorrector method, we captured the nature of the obtained solution for different arbitrary orders. We investigated the influence of the fractional operator to present and discuss some interesting properties of the novel coronavirus infection. 2022 by the authors. Licensee MDPI, Basel, Switzerland. -
Modified Non-local Means Model for Speckle Noise Reduction in Ultrasound Images
In the modern health care field, various medical imaging modalities play a vital role in diagnosis. Among the modalities, Medical Ultrasound Imaging is the most popular and economic modality. But its vulnerability to multiplicative speckle noise is challenging, which obscure accurate diagnosis. To reduce the influence of the speckle noise, various noise filtering models have been proposed. But while filtering the noise, these filters exhibit limitations like high computational complexity and loss of detailed structures and edges of organs. In this article, a novel Non-local means (NLM)-based model is proposed for the speckle reduction of Ultrasound images. The design parameters of the NLM filter are obtained by applying the Grey Wolf Optimization (GWO) to the input image. The optimized parameters and the noisy image are passed to the NLM filter to get the denoised image. The efficiency of this proposed method is evaluated with standard performance metrics. A comparative analysis with existing methods highlights the merit of the proposal. 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. -
Modified Montmorillonite Catalysed Ultrasonic Assisted one-pot Synthesis of Novel 2,3-dihydroisoxazolo[5,4-d] pyrimidin-4(7H)-ones as Potential Anticancer Agents
The development of novel compounds with potential anticancer activity is imperative for combating the challenges posed by cancer. In this study, a modified montmorillonite based catalyst is employed for the synthesis of 2,3-dihydroisoxazolo[5,4-d] pyrimidin-4(7H)-ones, which are promising candidates for anticancer agents. Montmorillonite is modified using mixed metal oxides, typically Al2O3 and CeO2, by a facile approach followed by standard spectroscopic and electron microscopic characterizations. It is then employed for the one-pot synthesis of a series of 2,3-dihydroisoxazolo[5,4-d] pyrimidin-4(7H)-ones. The synthesis protocol, mediated by ultrasound, is simple, efficient, and environment friendly. The mixed metal oxide pillared montmorillonite catalyst exhibits high catalytic activity and selectivity, facilitating the formation of the desired compounds in good to excellent yields. The synthesized compounds are characterized using various spectroscopic techniques such as 1H NMR, 13C NMR and mass spectrometry. Furthermore, the anticancer activity of the synthesized compounds is evaluated against a series of cancer cell lines, revealing promising cytotoxic effects. The findings of this study highlight the potential of novel 2,3-dihydroisoxazolo[5,4-d] pyrimidin-4(7H)-ones as promising anticancer agent, warranting further investigation for their therapeutic potential. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024. -
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Modified Metal Organic Frameworks for Electrocatalytic Water Splitting and Energy Storage Applications
Metal-organic frameworks (MOFs) are a class of crystalline material formed by the newlinecombination of metal ions/clusters along with organic linkers. This work is mainly based on newlinesynthesizing MOFs and their application in electrocatalytic water splitting and newlinesupercapacitors. The MOFs synthesized in the present work are Ni-Cu, {Mn-NiNH2(h2fipbb)}, Mn-MOF/rGO, and Sm-MOF/rGO/PANI using different ditopic and tritopic linkers. Using various characterization techniques, the formation of the synthesized MOFs is confirmed. The increasing use of fossil fuels now contributes to a number of environmental problems, including climate change and global warming. High-performance electrochemical energy storage devices are essential for portable electronics, electric cars, newlineand renewable energy storage medium, driving demand. MOFs are emerged as a promising newlinecontender for energy storage applications owing to their novel microstructures, atomically dispersed metal centers, and earth-abundant metal components. Electrochemical water splitting is a crucial approach in the pursuit of producing environmentally friendly fuels such newlineas H2 and O2, reducing our dependence on traditional fossil fuels while promoting newlinesustainable and clean energy sources. In order to produce hydrogen with the best efficiency and lowest cost, these MOFs are used. Electrochemical studies like cyclic voltammetry, galvanostatic charge discharge, and electrochemical impedance spectroscopy reveal that the prepared MOFs can be used as supercapacitors. Linear sweep voltammetry and Tafel plot determine the performance of these MOFs towards water splitting studies. Supercapacitors, which are electrochemical capacitors, are popular energy storage devices with quick charge rate, high power density, excellent rate capability, and outstanding life expectancy. -
Modified Genesio-Tesi systems with trigonometric functions and the Caputo fractional derivative
The new fractional-order Genesio-Tesi system is introduced, and its boundedness, stability of the equilibrium points, Lyapunov stability, uniqueness of the solution, and bifurcation are all discussed in this paper. Using the efficient predictor-corrector approach, we statistically analyze the Genesio-Tesi system in fractional order. The results effectively conceptualize and visualize the novel fractional order Genesio-Tesi systems that are suggested. When the systems order shifts from integer to fractional, the revolution around the fixed point increases. The chaotic character of the modified Genesio-Tesi system is comparable to that of the original Genesio system. The major changes were made to the Geensio-Tesi system by including the trigonometric functions, keeping the initial conditions and parameter values intact. The system is fractionalised with the help of Caputo fractional operator. In particular, the modified systems nature is more complex, which may aid in signal processing and secure communication. Future research on the modified Genesio-Tesi system can now proceed in light of this finding. This article offers a fresh approach to utilizing and thoroughly researching the Genesio-Tesi systems that have been provided. CSP - Cambridge, UK; I&S - Florida, USA, 2024 -
Modified eco-friendly and biodegradable chitosan-based sustainable semiconducting thin films
Semiconducting materials are pivotal in various fields, such as solar cells, LEDs, photovoltaic cells, etc. A nature-friendly chitosan is a good film-forming, water-soluble polymer that is modified to a small band-gap polymer for various optoelectronic applications. Choline chloride:ethylene glycol:glycerin (1:1:1) deep eutectic solvent (DES)-modified activated carbon is incorporated into the chitosan matric and this composite is fabricated into thin films via spin coating methodology. The obtained films are subjected to multiple studies such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), impedance spectroscopy, and UVvis spectroscopy to perceive the thin-films microstructure, morphology, conductance, band gap, and optical nature. The integration of DES-modified activated carbon has significantly improved the charge transfer capacity of chitosan by reducing the band gap from 4.0 to 2.0 eV. These notable characteristics exhibited by the modified films can be key to sustainable semiconducting materials and have the potential to transform several optoelectronic applications. 2024 The Author(s). Polymers for Advanced Technologies published by John Wiley & Sons Ltd. -
Modified ceria as a substitute for sulfuric acid in the liquid phase nitration of toluene
Ceria, sulfated ceria, ceria-zirconia and sulfated ceria-zirconia catalysts were prepared via the co-precipitation method and calcined at 823 K. The catalysts were characterized by XRD, BET surface area, FTIR, TGA and EDAX. The acidity of the catalysts was studied by pyridine adsorbed FTIR. All the peaks in XRD correspond to the cubic fluorite structure of ceria. The crystallite size of the catalysts was found to be 4-8 nm. Incorporation of zirconia stabilizes the surface sulfate species and thus increases the sulfate content. Sulfation decreases the surface area, but increases the acidity, leading to enhanced catalytic activity. All the catalysts were found to be stable up to 923 K. Catalytic activities were tested towards the liquid phase nitration of toluene. A maximum conversion of about 34 % is achievable for the nitration of toluene to dinitrotoluene. Solid acids effectively play the role of sulfuric acid in the reaction, assisting the formation of nitronium species. 2012 Akadiai Kiad Budapest, Hungary. -
Modified Ceria as a Substitute for Sulfuric Acid in the Liquid Phase Nitration of Toluene
Reaction, Kinetics, Mechanisms and Catalysis, ISSN NO. 1878-5204