Optical Property of Contained Fullerene Polymers

The presented study in the field of optical area is about receiving polymer new materials in the way of doping a small amount of fullerene С60. Under the method of preparing samples it is revealed characteristics of an interaction between polymer components and doping materials. Significant absorption of ultraviolet radiation by studied samples at the certain concentration of the doping material is presented in the result of the optical study. It is shown that metal-fullerene nanostructures which are on the polymer surface call surface resonance of plasmon absorption.

Klynotron with using the open resonator and symmetric conical corrugated mirrors – goratron

А further development of the radial klynoorotron idea – klynotron with symmetric conical radial corrugated resonator mirrors, is presented in the article. Strong coupling volume and surface resonance fields in the double conical mirrors in such a device is formed due to which the synchronous harmonic field is in the entire intermirror space. All saying above makes it possible to use a wide electronic flow. The conical mirror geometry provides a klynotron effect. As a result, not only the permissible device power is increased, but also its efficiency in comparison with a conventional radial klynoorotron. The article presents the calculating results of the Goratron at b0 = 0.51. The solution of the two-dimensional boundary value problem for the potentialV(r, z) = rBj(r, z), which determines Goratron resonator axisymmetric oscillation Em01, was carried out by standard packages for solving general partial differential equations using finite elements. The distribution analysis Er(r, z), Ez(r, z), Bj(r, z) shows that the field periodic component exists in the entire space between the comb mirrors. Given feature allows to use a wide (up to l/4) electron flow. Goratron electron flow modelcontains 16 layers along z, the equations of motion were relativistic. The electronic efficiency averaged over all layers is more than 30 %, which is 1.5 times higher than that obtained in the radial klynotron efficiency calculations.

Ultrafast evolution of bulk, surface and surface resonance states in photoexcited $$\hbox {Bi}_{2}\hbox {Te}_{3}$$

We use circular dichroism (CD) in time- and angle-resolved photoemission spectroscopy (trARPES) to measure the femtosecond charge dynamics in the topological insulator (TI) $$\hbox {Bi}_{2}\hbox {Te}_{3}$$ Bi 2 Te 3 . We detect clear CD signatures from topological surface states (TSS) and surface resonance (SR) states. In time-resolved measurements, independently from the pump polarization or intensity, the CD shows a dynamics which provides access to the unexplored electronic evolution in unoccupied states of $$\hbox {Bi}_{2}\hbox {Te}_{3}$$ Bi 2 Te 3 . In particular, we are able to disentangle the unpolarized electron dynamics in the bulk states from the spin-textured TSS and SR states on the femtosecond timescale. Our study demonstrates that photoexcitation mainly involves the bulk states and is followed by sub-picosecond transport to the surface. This provides essential details on intra- and interband scattering in the relaxation process of TSS and SR states. Our results reveal the significant role of SRs in the subtle ultrafast interaction between bulk and surface states of TIs.

Silver nanoparticles from Ziziphus spina-christi (L.) Desf. fruits extract and their antimicrobial activity

An easy and ecofriendly method to synthesize silver nanoparticles from different stages of ripening fruit extracts of Ziziphus spina-christi is demonstrated. UV-Vis spectroscopy showed a surface resonance peak at 423, 428 and 438 nm corresponding to the formation of AgNPs from ripened, unripened and young fruits, respectively. On the basis of XRD analysis the particle size of three stages of fruit ripening was found to range between 16.5 and 50.76 nm and all had silver metal which was confirmed by EDX. The inhibitory efficacy of AgNPs increased with the ripening progress such as ripened fruit > unripened fruit > young fruit against all tested human pathogenic microbes.

Equine pregnancy-specific glycoprotein CEACAM49 secreted by endometrial cup cells activates TGFB

In early equine pregnancy, a highly invasive trophoblast cell subpopulation, the chorionic girdle cells, invade the endometrium and form endometrial cups (EC). These cells express classical MHC molecules, thereby stimulating a humoral and cellular immune response, resulting in a massive accumulation of maternal CD4+ and CD8+ T cells around the EC. Nevertheless, no immediate destruction of endometrial cups by maternal lymphoid cells occurs, presumably due to immune tolerance. Although the environment of EC is rich in TGFB and in FOXP3+, CD4+ T cells, the mechanisms leading to tolerance have not been elucidated. Recently, we discovered that equine trophoblast cells secrete pregnancy-specific glycoproteins (PSGs). Since human and murine PSGs activate latent TGFB, we hypothesized that equine PSGs may have a similar activity. We performed plasmon surface resonance experiments to show that equine PSG CEACAM49 can directly bind to the latency-associated peptide (LAP) of both TGFB1 and TGFB2. We then found that the binding of CEACAM49 leads to the activation of TGFB1 as determined by both ELISA and cell-based assays. Furthermore, the activation of TGFB is a unique function of PSGs within the human CEA family, because CEACAM1, 3, 5, 6, 8 do not activate this cytokine. This finding further strengthens the classification of CEACAM49 as an equine PSG. Based on our results, we hypothesize that activation of latent TGFB in the EC environment by equine PSGs secreted by invasive trophoblast cells, could contribute to the generation of regulatory T cells (Tregs) to maintain immune tolerance.

Bromelain Inhibits SARS-CoV-2 Infection in VeroE6 Cells

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The initial interaction between Transmembrane Serine Protease 2 (TMPRSS2) primed SARS-CoV-2 spike (S) protein and host cell receptor angiotensin-converting enzyme 2 (ACE-2) is a pre-requisite step for this novel coronavirus pathogenesis. Here, we expressed a GFP-tagged SARS-CoV-2 S-Ectodomain in Tni insect cells. That contained sialic acid-enriched N- and O-glycans. Surface resonance plasmon (SPR) and Luminex assay showed that the purified S-Ectodomain binding to human ACE-2 and immunoreactivity with COVID-19 positive samples. We demonstrate that bromelain (isolated from pineapple stem and used as a dietary supplement) treatment diminishes the expression of ACE-2 and TMPRSS2 in VeroE6 cells and dramatically lowers the expression of S-Ectodomain. Importantly, bromelain treatment reduced the interaction between S-Ectodomain and VeroE6 cells. Most importantly, bromelain treatment significantly diminished the SARS-CoV-2 infection in VeroE6 cells. Altogether, our results suggest that bromelain or bromelain rich pineapple stem may be used as an antiviral against COVID-19.HighlightsBromelain inhibits / cleaves the expression of ACE-2 and TMPRSS2Bromelain cleaves / degrades SARS-CoV-2 spike proteinBromelain inhibits S-Ectodomain binding and SARS-CoV-2 infection