Zeitschriftenaufsätze

Building the desirable superstructure of polyethylene is one of the important topics for developing high value-added products, which brings potential benefits for society and sustainable development. Crystalline order is the ubiquitous superstructure for enhancing mechanical properties of polymeric materials. In this work, polystyrene copolymers (c-PS) are incorporated into pores of silica through the wet-impregnation procedure of styrene and p-chloromethyl styrene followed by the in-situ free-radical copolymerization. Metallocene catalyst is further immobilized on supported silica. This incorporated c-PS is proved to be coated on the surface of silica pore walls rather than blocking the interparticle channels. The swelling behavior of c-PS inside the pores are performed by pulsed field gradient NMR (PFG-NMR) and thermoporosimetry (TPM-DSC), where a swelling behavior is shown in the toluene owing to the matched solubility parameters between the c-PS and toluene. According to the swelling behavior of c-PS confined in the pores, a compartmentalization is created hindering the formation of chain overlaps and increasing the crystallinity order of nascent polymers. As a result, the nascent polyethylene with a high crystallinity (i.e., bulk crystallinity Xc,DSC=72.9 % and linear crystallinity Xc,WAXD=90.5 %) is synthesized. There is a considerable activity (i.e., 3.8×106 g PE&hahog;(molZr&hahog;h)^-1) at 70˚C. Finally, the particle morphology of the nascent polyethylene is investigated based on the swelling behavior of c-PS.

Introduction: The emergence of a new member of the Coronaviridae family, which caused the 2020 pandemic, requires detailed research on the evolution of coronaviruses, their structure and properties, and interaction with cells. Modern nanobiotechnologies can address the many clinical challenges posed by the COVID-19 pandemic. In particular, they offer new therapeutic approaches using biocompatible nanostructures with “specific” antiviral activity. Therefore, the nanosized spherical-like molecule (0.72 nm in diameter) composed of 60 carbon atoms, C60 fullerene, is of interest in terms of fighting coronaviruses due to its high biological activity. In here, we aim to evaluate the effectiveness of anticoronavirus action of water-soluble pristine C60 fullerene in the model and in vitro systems. As a model, apathogenic for human coronavirus, we used transmissible gastroenteritis virus of swine (TGEV), which we adapted to the BHK-21 cell culture (kidney cells of a newborn Syrian hamster).Methods: The shape and size of the particles present in C60 fullerene aqueous colloidal solution (C60FAS) of given concentration, as well as C60FAS stability (value of zeta potential) were studied using microscopic (STM, scanning tunneling microscopy, and AFM, atomic force microscopy) and spectroscopic (DLS, dynamic light scattering) methods. The cytopathic effect of TGEV was determined with the help of a Leica DM 750 microscope and the degree of monolayer changes in cells was assessed. The microscopy of the viral suspension was performed using a high resolution transmission electron microscope (HRTEM; JEM-1230, Japan). Finally, the search for and design of optimal possible complexes between C60 fullerene and target proteins in the structure of SARS-CoV-2 coronavirus, evaluation of their stability in the simulated cellular environment were performed using molecular dynamics and docking methods.Results: It was found that the maximum allowable cytotoxic concentration of C60 fullerene is 37.5 ± 3.0 [my]g/ml. The investigated C60FAS reduces the titer of coronavirus infectious activity by the value of 2.00 ± 0.08 TCID50/ml. It was shown that C60 fullerene interacts directly with SARS-CoV-2 proteins, such as RdRp (RNA-dependent RNA polymerase) and 3CLpro (3-chymotrypsin-like protease), which is critical for the life cycle of the coronavirus and, thus, inhibits its functional activity. In both cases, C60 fullerene fills the binding pocket and gets stuck there through stacking and steric interactions.Conclusion: Pioneer in vitro study to identify the anticoronavirus activity of water-soluble pristine C60 fullerenes indicates that they are highly promising for further preclinical studies, since a significant inhibition of the infectious activity of swine coronavirus of transmissible gastroenteritis in BHK-21 cell culture was found. According to molecular modeling results, it was shown that C60 fullerene can create the stable complexes with 3CLpro and RdRp proteins of SARS-CoV-2 coronavirus and, thus, suppress its functional activity.

Fabricating highly homogeneous plasmonic nanostructures over a large area and optically evaluating their structural quality are challenging. Here, we propose an elegant approach to achieve various dense nanoparticle arrays with tunable symmetries over centimeter-scale dimensions and optically evaluate the structural quality by spatially mapping nonlinear emissions from L-, U-, and O-shaped individual nanoparticles. In particular, the spectral overlapping of the second harmonic (SH) and two-photon luminescence (TPL) emissions is separated, and excitation polarization dependence and spatial fluctuations of the nonlinear signal across the nanostructures are investigated. Narrow Gaussian-distributed peaks in the intensity histogram of SH and TPL emissions confirm the high-level uniformity of the fabricated arrays. Distinct spatial distributions of SH and TPL emissions are observed, and their spatial correlation is very weak over large-area nanostructures. Furthermore, SH signals are demonstrated as a more sensitive indicator of the structural quality of nanoparticle arrays. Our findings not only offer an efficient way of constructing versatile large-scale nanostructures but also enable spatial nonlinear optics tailoring for applications of nano-optics and quantum information.