Synthesis and in vitro Study of Artemisinin/Synthetic Peroxide-Based Hybrid Compounds against SARS-CoV-2 and Cancer

The newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cause life-threatening diseases in millions of people worldwide, in particular, in patients with cancer, and there is an urgent need for antiviral agents against this infection. While in vitro activities of artemisinins against SARS-CoV-2 and cancer have recently been demonstrated, no study of artemisinin and/or synthetic peroxide-based hybrid compounds active against both cancer and SARS-CoV-2 has been reported yet. However, the hybrid drug's properties (e. g., activity and/or selectivity) can be improved compared to its parent compounds and effective new agents can be obtained by modification/hybridization of existing drugs or bioactive natural products. In this study, a series of new artesunic acid and synthetic peroxide based new hybrids were synthesized and analyzed in vitro for the first time for their inhibitory activity against SARS-CoV-2 and leukemia cell lines. Several artesunic acid-derived hybrids exerted a similar or stronger potency against K562 leukemia cells (81–83 % inhibition values) than the reference drug doxorubicin (78 % inhibition value) and they were also more efficient than their parent compounds artesunic acid (49.2 % inhibition value) and quinoline derivative (5.5 % inhibition value). Interestingly, the same artesunic acid-quinoline hybrids also show inhibitory activity against SARS-CoV-2 in vitro (EC₅₀ 13–19 μm ) and no cytotoxic effects on Vero E6 cells (CC₅₀ up to 110 μM). These results provide a valuable basis for design of further artemisinin-derived hybrids to treat both cancer and SARS-CoV-2 infections.     

Characterization of Total and Individual Sterols in Canola Sprouts

In this study, the contents of total and individual phytosterols in sprouts made from seeds of seven canola (Brassica napus L.) lines (Acropolis, Banjo, Jetton, KS-7740, KSM3-1-124, Mussette and Virginia), grown at three locations in Virginia (Orange, Petersburg and Suffolk), were determined. Canola sprouts contained, on an average, 36.3 g sterols in 100 g of unsaponifiable matter (UNSAP), 10.7 mg sterols in 1 g of oil and 2.4 mg sterols in 1 g of dry sprouts. The contents of individual phytosterols (μg per g of oil) in canola sprouts were 1,162 brassicasterol, 3,799 campesterol, 34 stigmasterol, 5,359 β-sitosterol, 201 Δ⁵-avenasterol and 97 Δ⁷-stigmastenol. Canola lines had significant effects on the contents of oil, brassicasterol and campesterol. Locations had significant effects on the oil, UNSAP, total sterols, brassicasterol, stigmasterol and β-sitosterol. The oil content in canola sprouts was positively correlated with total sterols and Δ⁵-avenasterol, whereas oil content was negatively correlated with brassicasterol content. In general, the contents of campesterol and β-sitosterol increased with an increase in total sterol content. The concentrations of sterols were in the following decreasing order: β-sitosterol > campesterol > brassicasterol > Δ⁵-avenasterol > Δ⁷-stigmastenol > stigmasterol. These results indicate that canola sprouts may have the potential as a natural source of dietary sterols and might be desirable for human nutrition.     

Influence of particle size distribution of calcium carbonate pigments on coated paper whiteness

The optical properties of pigments used for paper coating are linked to their morphology. The light scattering through coated layers depends upon the size and the size distribution of the pigments and their packing behavior. In this report the effect of particle packing of various calcium carbonate pigments on the whiteness of the final coated paper is studied. Different grades of calcium carbonate pigments of different particle size distribution and optics were used for coating applications on base papers. Base papers of different optics were also selected. The entire study was carried out at different coat weights. It was observed that the overall scattering from the coated sheet depends upon the light scattering from the base paper as well as through the coated layer. Higher light scattering through the coated layer will lower the effect of the base paper, whether it is dark or bright. So high bright and white pigments are not only the criteria for an enhancement in the optical properties of coated paper; the particle size and size distribution should also be considered before introducing any pigment into a coating formulation. The base optics should also be chosen on the bases of the pigments’ optics and their morphology.     

Segmental interactions,interfacial polarization,and gigantic dielectric permittivity in ethylene vinyl acetate copolymer-carbon nanotube composites

This study reports copolymer composition tailored wrapping of carbon nanotubes, leading to a gigantic dielectric permittivity and peculiar nonlinear rheological response in a nonfluoro copolymer/carbon nanotube (CNT) hybrid system. Specifically, we observed a strong interfacial polarization effect in ethylene vinyl acetate (EVAc) copolymer/CNT nanocomposites, resulting in a dielectric permittivity of approximately 4000 at 10 Hz and 450 (dielectric loss <1) at 1 kHz, with only 1% volume fraction of CNTs and 40% vinyl acetate (VAc) content. No such effect was observed in EVAc with 12% VAc. Extensive amplitude oscillatory rheology studies prompted us to propose a novel hook-wrap-type mechanism, wherein polar interactions act as hooks and nonpolar segments allow wrapping, depending on the optimal interactions between the CNT and copolymer. Raman spectroscopy, small-angle x-ray scattering, and relaxation studies also revealed a significant change in segmental dynamics and mass fractal compactness with a change in the VAc content. This work provides a melt processing-based scalable route to develop polymer dielectrics while advancing the fundamental understanding of polymer-CNT interactions and the underlying mechanisms of dielectric behavior in nanocomposites.     

Preparation of stable Pd nanoparticles with tunable size for multiple immunolabeling in biomedicine

Stable Pd nanoparticles (PdNP) with a tunable size (3-15 nm) were synthesized by controlled chemical reduction of PdCl₂ with sodium citrate in water. The morphology of PdNP was characterized by transmission electron microscopy, while their stability in solution was verified by quasi-elastic light scattering and small-angle X-ray scattering. Intensive stirring of reacting mixture played a vital role in achieving reproducible particle sizes. Controlled changes of pH and initial concentrations were employed in fine-tuning particle size distributions. Finally, 10 nm PdNP were conjugated with goat anti-mouse IgG antibody as proved by electrophoresis (SDS-PAGE) and used for ultrastructural immunolabeling, which confirmed suitability of PdNP for multiple immunolabeling in biomedicine.     

Radiation‐assisted morphology modification of LDPE/TPS blends: A study on starch degradation‐processing‐morphology correlation

Potato starch was radiolytically degraded to different extents by irradiating with Co‐60 gamma radiation in wide dose range. The degraded starch was plasticized using glycerol and water to obtain radiation processed thermoplastic starch (RTPS). Blends of different RTPS and low density polyethylene (LDPE) were prepared by internal melt mixing. Characterization of blends using differential scanning calorimetry, thermogravimetric analysis, X‐ray diffraction, Fourier transformed infrared spectroscopy, scanning electron microscope, melt flow, contact angle, and soil burial studies indicated changes in the blend morphology and biodegradation behavior with the increase in the dose imparted to the starch fraction. Molecular weight of starch decreased substantially in the dose range of the study. The melt viscosity of LDPE/RTPS blend decreased whereas crystallinity of LDPE phase increased with the incorporation of RTPS. No significant change in the carbonyl index and thermal stability of the blends was observed in the dose range studied; therefore, the observed changes in the physical and thermal properties of the blends were attributed primarily to the kinetic factors affecting crystallization and time‐dependent phase separation process. Biodegradability of blends varied with the radiation dose imparted to starch component of blend, suggesting better encapsulation of RTPS by LDPE chains. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Correlation between surface energy and uptake behavior of radiation-grafted methacrylic acid-g-LDPE

An efficient and low-cost effluent adsorbent has been developed by grafting an ionizable monomer onto polyolefin surface and its efficacy was tested for dyes and metal ion uptake from aqueous medium. The grafted matrix was synthesized by optimizing various experimental parameters such as irradiation dose, dose rate, monomer concentration, inhibitor concentration, surfactant concentration, and backbone thickness. Grafting yield decreased with dose rate and thickness and increased with the concentration of methacrylic acid and inhibitor. Grafting kinetics studies indicated that grafting rate is comparatively much affected by dose rate that monomer concentration. Surface energy of the grafted surface was accessed from dynamic contact angle measurements. Uptake study of Basic Red 29, Methylene Blue showed high correlation with grafting yield and polar component of the surface energy; however, metal ion uptake was exceptionally high at ~25 grafting (%), highlighting anomalous behavior of MAA-g-LDPE with respect to surface energy and total ion uptake capacity.     

Radiation‐processed polychloroprene‐co‐ethylene–propene diene terpolymer blends: Evaluation of blend morphology,miscibility, and physical properties

The miscibility of polychloroprene rubber (CR) and ethylene–propylene–diene terpolymer rubber (EPDM) was studied over the entire composition range. Different blend compositions of CR and EPDM were prepared by initially mixing on a two‐roll mill and subsequently irradiating to different gamma radiation doses. The blends were characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy, density measurement, hardness measurement, and solvent permeability analysis. The compatibility of the blends was studied by measuring the glass transition temperature and heat capacity change of the blends. The immiscibility of blends was reflected by the presence of two glass transition temperatures; however, partial miscible domains were observed due to inter diffusion of phases. Permeation data fitted best with the Maxwell's model and indicated that in CR‐EPDM blends, EPDM exists as continuous phase with CR as dispersed phase for lower CR weight fractions and phase inversion occurred in 40–60% CR region. It was observed that CR improved oil resistance of EPDM; however, the effect was prominent for blends of >20% CR content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Study on PVC composites containing Eugenia jambolana wood flour

This article describes the properties of composites using unplasticized PVC matrix and wood flour (obtained by crushing the bark of Eugenia jambolana) as filler. Composites were prepared by mixing PVC with varying amounts of wood flour (ranging from 10–40 phr; having particle sizes of 100–150 μm and <50μm) using two‐roll mill followed by compression molding. The effect of wood flour content and its particle size on the properties, i.e., mechanical, dynamic mechanical, and thermal was evaluated. Tensile strength, impact strength, and % elongation at break decreased with increasing amounts of wood flour. Stiffness of the composites (as determined by storage modulus) increased with increasing amounts of the filler. Modulus increased significantly when wood flour having particle size <50 μm was used. Morphological characterization (SEM) showed a uniform distribution of wood flour in the composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

LDPE/EVA/PCR/MWNT nanocomposites: Radiation crosslinking and physicomechanical characteristics

Nanocomposites of low‐density polyethylene (LDPE)/ethyl vinyl acetate (EVA)/poly(chloroprene) rubber (PCR) blends and multiple walled carbon nanotubes (MWNT) were prepared in different compositions by melt mixing. The nanocomposites were subjected to different radiation doses and efficacy of radiation crosslinking and physic‐mechanical characteristics were analyzed in detail. Gel content and crosslinking density increased with dose and with the MWNT fraction in the nanocomposites. The elastic modulus of the nanocomposite increased, while elongation at break exhibited downward trend with radiation dose. Micromechanical modeling of elastic modulus indicated presence of agglomeration in the matrix. Bulk density of the nanocomposites increased with the addition of MWNT while the melt flow index of the nanocomposites decreased sharply. DSC, XRD and TGA investigations revealed the peculiarity of the MWNT led nucleation in LDPE/EVA/PCR/MWNT nanocomposites. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers