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Anticancer-drug delivery is now becoming a challenging approach for researchers as it allows controlled drug delivery near cancerous cells with minimized generic collection and the avoidance of secondary side effects. Hence in this work, the applications of nanostructures as anticancer drug-delivery carriers were widely investigated to target cancerous tissues. Based on DFT calculations, we investigated the transition metal-doped boron nitride nanostructure as a drug-delivery agent for the gemcitabine drug utilizing the B3LYP/6-31G (d, p) level of theory. In this research, the adsorption energy and electronic parameters of gemcitabine on the interaction with the metal-doped BN nanostructures were studied. It has been observed that metal doping significantly enhances the drug-delivery properties of BN nanostructures. Among the investigated nanostructures, Ni-BN has been found to be the most prominent nanostructure to transport gemcitabine with an elevated value of adsorption energy in both the gas phase (-45.79) and water media (-32.46). The interaction between gemcitabine and BN nanostructures was confirmed through frontier molecular orbitals and stabilization energy analysis. The fractional charge transfer, MEP, NCI, and NBO analyses exposed the charge transfer from drug molecule to the BN nanostructures. Transition density maps and UV-VIS spectra were also plotted to investigate the excited-state properties of the designed complexes. Thus, the present study provides an in-depth interaction mechanism of the gemcitabine drug with BN, which reveals that metal-doped BN nanostructures can be a favorable drug-delivery vehicle for the gemcitabine anticancer drug.

In the present investigation, quantum chemical calculations have been performed in a systematic way to explore the optoelectronic, charge transfer, and nonlinear optical (NLO) properties of different bis(dicyanomethylene) end-functionalized quinoidal oligothiophenes. The effect of different conformations (linking modes of thiophene rings) on conformational, optoelectronic, and NLO properties are studied from the best-performed dimer to octamer. The optical and NLO properties of all the selected systems (1–7) are calculated by means of density functional theory (DFT) methods. Among all the designed compounds, the largest linear isotropic (αiso) polarizability value of 603.1 × 10–24 esu is shown by compound 7 which is ∼12, ∼16, ∼9, ∼11, ∼10, and ∼4 times larger as compared to compounds 1–6, respectively. A relative investigation is performed considering the expansion in third-order NLO polarizability as a function of size and conformational modes. Among all the investigated systems, system 7 shows the highest value of static second hyperpolarizability ⟨γ⟩ with an amplitude of 7607 × 10–36 esu at the M06/6-311G** level of theory, which is ∼521, ∼505, ∼38, ∼884, ∼185, and ∼15 times more than that of compounds 1–6, respectively. The extensively larger ⟨γ⟩ amplitude of compound 7 with higher oscillator strength and lower transition energy indicates that NLO properties are remarkably dependent upon linking modes of thiophene rings and its chain length. Furthermore, to trace the origin of higher nonlinearities, TD-DFT calculations are also performed at the same TD-M06/6-311G** level of theory. Additionally, a comprehensive understanding of the effect of structure/property relationship on the NLO polarizabilities of these investigated quinoidal oligothiophenes is obtained through the inspection of Frontier molecular orbitals, the density of states (TDOS and PDOS), and molecular electrostatic potential diagrams including the transition density matrix. Hence, the current examination will not just feature the NLO capability of entitled compounds yet additionally incite the interest of experimentalists to adequately modify the structure of these oligothiophenes for efficient optical and NLO applications.

The current research work presents a low cost, efficient and innovative active aerostatic thrust bearing which is controlled through a combination of the Arduino board, feedback transducers and high-speed valves. The purpose is to make low cost, compact active aerostatic thrust bearing with overall small dimensions and compact size. A prototype design is done in solid works with small dimensions and components are produced with the help of the high precision machining process. There are two high-speed electropneumatic valves which are controlled through pulse width modulation techniques. These high-speed electro-pneumatic valves modify the supply pressure of aerostatic bearing to achieve desired air height gap. There are two novel pressure sensors which provide a feedback signal for control. The test bench to perform experiments has been explained. The performance of the proposed aerostatic bearing is checked both in open loop and closed loop configuration with respect to static and dynamic conditions.

Graphic abstract An outbreak of respiratory disorder caused by coronavirus has been named as coronavirus infection 2019 (COVID-19). To find a specific treatment against this disease researchers are at the frontline. To cure COVID-19, favipiravir (FPV) has been reported as an effective drug based on its high recovery rate. Among nanomaterials, fullerene C60 has achieved enormous attention as a drug delivery vehicle due to its good bioavailability and low toxicity. Hence, in this work, we have investigated the potential of metal-doped fullerene as a drug carrier, based on DFT calculations by using M06-2X functional and 6-31G(d) basis set in water media. In this research electronic parameters and adsorption energy of FPV on interaction with metal-doped (Cr, Fe, and Ni) fullerene is studied. The charge transfer between drug and doped fullerene has been studied through electrophilicity indexes. The structural and electronic properties are explored in terms of adsorption energy through frontier molecular orbital (FMO) and density of state (DOS). It is observed that doping of fullerene C60 with Cr, Fe, and Ni metals significantly enhances the drug delivery rate and provides numerous advantages including controlled drug release at specific target sites which minimize the generic collection in vivo and reduce the side effects. Thusly, it is suggested that our designed metal-doped complexes might be efficient candidates as drug delivery materials for COVID-19 infection. Supplementary Information The online version contains supplementary material available at 10.1007/s11696-021-01815-4.

The electronic, magnetic and optical properties of Ni-doped CdSe diluted magnetic semiconductors have been explored by density functional theory-based FPLAPW method as incorporated in the Wien2k code. The band structure and density of states analysis for up spin channel and down spin channel illustrate half-metallic ferromagnetic behaviour. The calculated values of the band gap in an insulating channel (down spin channel) increases from 0.4 to 0.8 eV with increasing the doping concentration of Ni from 6.25 to 25%. The magnetic moment of Ni decreases and magnetic moment on nonmagnetic side increases, which shows the strong pd-hybridization. Furthermore, the optical properties are characterized in terms of dielectric constants, refractive index, extinction coefficient, absorption coefficient and optical loss factor. The static values of the dielectric constant and refractive index are consistent with each other.

The aquatic environment is continuously being polluted by heavy metals released from industrial, domestic, agricultural, and medical applications. It is difficult to remove heavy metals, as they are nonbiodegradable. Heavy metals cause genotoxicity and serious carcinogenic disorders. Various conventional methods have been used for the removal of heavy metals, but these are time-consuming and not economical, so green methods, being economical, are preferred over conventional methods. Adsorption, being effective, environmentally friendly, and cheap, is often preferred. The present investigation investigated the adsorption efficiency of agrowaste-based biosorbents for removal of Pb(II) ion from the synthetic wastewater. Mixed biomass of banana peel and potato peels was used to create biosorbents. The biosorbents were characterized in terms of structural and surface morphology by SEM, while functional groups were analyzed by FT-IR and XRD analysis. The adsorption of Pb(II) was studied by a batch method, and various experimental parameters were studied. Optimum conditions for the removal of lead were pH = 5, concentration = 10 ppm, adsorbent dosage = 1.0 g, and contact time = 2 h. Kinetic modelling studies showed that the adsorption of Pb(II) ions followed a pseudo-second-order mechanism, and the Langmuir isotherm model was found to fit well for this study. Highlights: Synthesis of biosorbents (mixed biomass of potato peel and banana peel, biochar, TiO2 nanocomposites). Characterization of prepared biosorbents (SEM, XRD, FT-IR). Optimized parameters (pH, initial concentration, adsorbent dosage, and contact time) for removal of pollutant.

In view of auspicious adsorption efficiency of nanocomposites (NCs), nanocomposites of graphene oxide (GO) were prepared with Fe3O4 by ultrasonic-assisted co-precipitation procedure and characterized by Fourier Transform Infra-red (FTIR), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Energy Dispersive X-Ray (EDX). The GO-Fe3O4 NCs were employed for adsorptive elimination of nitrate (NO3¯) and phosphate (PO43¯) ions from aqueous medium as a function of pH (1-10), GO-Fe3O4 NCs dose (0.05-0.1 g), contact time (0-1444 min) and ions concentration (10-100 mg L-1). Among kinetic and isotherms models, NO3¯ and PO43¯ ions removal followed the pseudo second order and Freundlich isotherm models. The maximum elimination capacity was achived up to 89 and 93 (%) for NO3¯ and PO43¯ ions, respectively at optimum operating conditions viz. pH 2, ions inital concentration 100 mg L-1, NCs dose 0.5 g and contact time 120 min. For the optimization of process variables response surface methodology (RSM) was emplyed. The results revealed that GO-Fe3O4 NCs have promising adsorption capacity for NO3¯ and PO43¯ ions and can be employed for the removal of NO3¯ and PO43¯ ions from effluents.

Graphical abstract, In the current study, the interaction of SARS-CoV-2 protein (A and B chains of nsp13) with different recently synthesized phenolic compounds (Sreenivasulu et al., Synthetic Communications, 2020, 112–122) has been studied. The interactions have been investigated by using molecular docking, quantum chemical and molecular dynamics simulations methods. The molecular structures of all the ligands are studied quantum chemically in terms of their optimized structures, 3-D orbital distributions, global chemical descriptors, molecular electrostatic potential plots and HOMO-LUMO orbital energies. All the ligands show reasonably good binding affinities with nsp-13 protein. The ligand L2 shows to have better binding affinities to Chain A and Chain B of nsp13 protein, which are −6.7 and −6.4 kcal/mol. The study of intermolecular interactions indicates that L2 shows different hydrophobic and hydrogen bond interactions with both chains. Furthermore, molecular dynamic simulations of the nsp13-L2 complex are obtained over a time scale of 60 ns, which indicates its stability and flexibility behavior as assessed in terms of its RMSD and RMSF graphs. The ADMET analysis also shows no violation of Lipinski rule (RO5) by studied phenolic compounds. We believe that the current findings will be further confirmed by in vitro and in vivo studies of these recent phenolic compounds for their potential as inhibitors for SARS-Co-V-2 virus.

A series of twelve Acceptor-π-Donor-π-Acceptor (A-π-D-π-A) topology-based donor molecules, where diketopyrrolopyrrole (DPP) as donor core unit is connected through furan which acts as conjugated π-bridge (CB) to aromatic derivatives (Ar) as acceptor units, have been investigated by making substitutions in acceptor units by using density functional theory(DFT) and time-dependent density functional theory (TD-DFT) for organic solar cell applications. The comparative study of optoelectronic properties indicates that thiadiazole with pyridine units containing molecules (M6b) exhibit lower energy of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels than those of oxadiazole and pyridine containing units (M6b). Among our investigated donors, the smallest Eg of 1.60 eV was observed for both M6a and M6b with distinctive broad absorption at 843 and 857 nm, respectively. Overall, smaller electron transfer (λe) values in contrast to hole transfer (λh) demonstrate that these donor compounds would be best for λe. The calculated open circuit voltage (Voc) is 2.45 and 2.17 eV, regarding bisPCBM and PC60BM (phenyl-C61-butyric acid methyl ester) acceptors. Thus, these theoretical calculations not only endorse the deep consideration between the chemical structures and optoelectronic characteristics of the donor-acceptor systems but also suggest appropriate materials for high-performance Organic Photovoltaics (OPV).

Most of the researchers are focusing to bring automation in mechanical systems. So, current research work presents a mechatronic system called active hydrostatic journal bearing that is a higher demand of fast-growing industrial needs. The objective is to improve the dynamics and static characteristics of hydrostatic journal bearing. To achieve the objective, a feedback servo controlled system is presented. A mathematical model is proposed for newly proposed active hydrostatic journal bearing with servo control. A comparison has been performed between the active hydrostatic journal bearing and traditional/conventional hydrostatic journal bearing under the influence of different dynamic conditions of load, viscosity, speed, and pressure. The results demonstrate that proposed active hydrostatic journal bearing has better performance, including controllability, stability, faster response, higher stiffness as well as better disturbance rejection. To further enhance the performance of proposed active hydrostatic journal bearing, two different control strategies are proposed such as proportional–integral–derivative and intelligent control. The results show that fuzzy logic–based intelligent control has faster response, greater amplitude reduction, and good stiffness against load. So, it shows that role of active lubrication in hydrostatic journal bearing will have potential applications in high load and high speed.

Dyes are one of the main water pollutants and many biological and environmental problems are associated with them. Rhodamine B (RhB) is one of the most commonly used dye in the textile, printing, paints, and paper industry. The present work reports the sorptive removal of Rhodamine B direct dye from wastewater onto developed cellulose and clay composites. Sorbent material cellulose (48 g) was extracted from 80 g of bagasse. Then cellulose and two types of acid-activated clays were used to make efficient sorbent namely, composite I and II. Various characterization techniques were used to study the physiochemical properties of the synthesized composites. Different sorption affecting parameters were optimized such as initial dye concentration, time, temperature, pH, and composite dose for the efficient sorption of RhB onto composites. Equilibrium time was 60 min for composite-I and 80 min for composite-II Non-linear equilibrium isotherm and kinetic models demonstrated the fitness of Pseudo-second order and Redlich-Peterson isotherm. Composite-I and II removed 85.9% and 95.6% of RhB at pH 2 in 120 min, respectively. The sorption efficiency was checked, and sorbents were applied to real textile effluent which showed promising removal efficiency of over 90%. To confirm the experimental results, computational optimization and vibrational calculations were carried out using the Gaussian 09 program package with 3–21 G, 6–311 G, and 6–311+G basic sets. Geometric parameters showed the planar geometry. In the case of FTIR spectra, fundamental ring vibrations were observed with C-H and C-C. This study suggests that the developed composites have exceptional sorption ability to remove the dye contents from aqueous media.

The present study explores a series of novel donor-π-acceptor (D-π-A) molecules containing 4,4′-dimethyldiphenylamine moiety as donor, 4,4′-dinitrodiphenylborane as acceptor while different π-bridges as efficient linkers between them, which comprises of ( − HC CH − )n, ( − Ph − )n and ( − Ph HC CH − )n combinations for compounds in series 1, 2 and 3, respectively. Quantum chemical computations are applied to calculate the linear polarizability (α), first (β) and second (γ) hyperpolarizabilities. A comparative analysis is performed considering an increase of NLO polarizabilities as a function of different π-linkers. Among the investigated compounds, 3c shows the largest first and second hyperpolarizabilities of 1378 × 10−30 and 34971 × 10−36 esu, respectively. Interestingly, an increase in NLO polarizability is observed by modifying the π-conjugated bridges and the largest NLO polarizability is observed for series 3 possessing (Ph HC CH − )n π-linker which is found due to its lower transition energy and higher oscillator strengths. Furthermore, TD-DFT investigations, frontier molecular orbitals (FMOs) and electron density difference (EDD) maps analysis have shown a more efficient intramolecular charge transfer character from donor to acceptor moieties through (Ph HC CH − )n π-linkers. The density of states (DOS) maps are showing explicit contributions of electronic states from different fragments of a molecular system where the partial contributions of (Ph HC CH − )n π-linkers is seen significant in HOMO-LUMO orbitals of all the systems in series number 3. Thus, we believe that our study will highlight the importance of different D-π-A chromophores having variant types of π-conjugation cores as discussed in the present investigation.

The electronic, optical and thermoelectric properties of LaAlO3 are studied under different pressure ranges (0–40 GPa) by using the full potential linear augmented plane wave method (FP-LAW). Calculations are done by Perdew–Burke–Ernzerhof generalized gradient approximation (PBEsol-GGA) by utilizing Wien 2k code. It was observed that with the increase of pressure band gap increased and the nature of band gap transform from indirect to direct. In Optical properties, optical conductivity, refractive index, absorption coefficient, and dielectric function are calculated at different pressures. Thermoelectric properties have been studied at temperature (150–800 K) and pressure (0–40 GPa) by using Boltz Trap code. At 800 K the values of power factor were 6.831 W K−2. cm. s and 22.13 W K−2. cm. s, respectively. Figure of merit was achieved up to 0.6. Results revealed that LaAlO3 is a suitable candidate for optoelectronic and thermoelectric devices.

Density functional calculations have been explored to analyze the structural, electronic and charge transfer properties of a doped TiO2 substrate and catechol–TiO2 interfaces for dye-sensitized solar cells. The results demonstrate that the dopant W6+ moves the CB (conduction band) edge downward and introduces 5d-unoccupied orbitals located in the CB bottom of the TiO2. On the other hand, the dopant Zn2+ shifts the CB edge upward with an insertion of 3d-occupied orbitals into the VB (valence band). In catechol–TiO2 systems, W6+ enlarges the energy difference between the LUMO of catechol and LUMO of TiO2, which enlarges the driving force for electron injection in turn and results in an increased short circuit current (Jsc). Our modeling injection dynamics and quantitative Bader analysis of the interfacial charge transfer have revealed that the catechol–TiO2 doped with W6+ provides faster and more electron injection for dye sensitized solar cells (DSSCs). While the Zn2+ doped system exhibits lower electron efficiency due to the minimized energy difference between the catechol LUMO and TiO2 CB.

In this work, the hydrogen storage capacity of the expanded hexagonal Boron Nitride (eh-BN) systems has been presented. We have employed a new equation of state (EOS) for hydrogen gas to figure out the hydrogen density distribution profiles in the eh-BN systems. In this regard, the environmental conditions (i.e., temperature and pressure) are considered in the prediction procedure using DFT single point calculations. The eh-BN systems with different layer spacings are studied by PBE method with consideration of the long range dispersion corrections. On account of the in-plane polar bonds, a series of adsorption positions are considered. Additionally, the adsorption energy and hydrogen density profiles are reported. Furthermore, the relation between uptakes and the interlayer spacings with the effects of the environmental conditions are also provided. The limit of the physical hydrogen storage capacity in a perfect eh-BN system at 243 K and 10 MPa is founded to be 2.96 wt.%.--//--eng Fu, Jing Wang, Ran Jia, Shamsa Bibi, Roberts I. Eglitis, Hong-Xing Zhang, Theoretical study on hydrogen storage capacity of expanded h-BN systems, Computational Materials Science, Volume 139, 2017, Pages 335-340, ISSN 0927-0256, https://doi.org/10.1016/j.commatsci.2017.08.015 published under the CC BY licence., Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017 TeamingPhase2 under grant agreement No. 739508, project CAMART2.