Possible Transmission Flow of SARS-CoV-2 Based on ACE2 Features

Angiotensin-converting enzyme 2 (ACE2) is the cellular receptor for the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that is engendering the severe coronavirus disease 2019 (COVID-19) pandemic. The spike (S) protein receptor-binding domain (RBD) of SARS-CoV-2 binds to the three sub-domains viz. amino acids (aa) 22–42, aa 79–84, and aa 330–393 of ACE2 on human cells to initiate entry. It was reported earlier that the receptor utilization capacity of ACE2 proteins from different species, such as cats, chimpanzees, dogs, and cattle, are different. A comprehensive analysis of ACE2 receptors of nineteen species was carried out in this study, and the findings propose a possible SARS-CoV-2 transmission flow across these nineteen species.     

The crystal and molecular structure of N-(methylsulfonyl)-N-(2,6)-(dimethylphenyl)methanesulfonamide

The title compound, crystallizes in the triclinic space group witha=8.232(4),b=9.159(2),c=10.230(3)Å. =74.07(3)°, =72.50(4)°, =63.65(3)° andZ=2. The structure was solved by direct methods and refined by full matrix least squares methods toR=0.054 for 1817 observed reflections. The plane containing the nitrogen and sulfur atoms is perpendicular to the aromatic plane. One of the S–O bonds in each methanesulfonyl group is in nearly eclipsed conformation with the N–C bond.     

Internal Structure of the Heisenberg and Robertson-Schrödinger Uncertainty Relations

It is known that the Heisenberg and Robertson-Schrödinger uncertainty relations can be replaced by sharper uncertainty relations in which the “classical” (depending on the gradient of the phase of the wave function) and “quantum” (depending on the gradient of the envelope of the wave function) parts of the variances 〈(Δx)²〉 and 〈(Δp)²〉 are separated. In this paper, three types of uncertainty relations for a different number of classical parts (2, 1 or 0) with different time behaviour of their left-hand and right-hand sides are discussed. For the Gaussian wave packet and two classical parts, the left-hand side of the corresponding relations increases for t→∞ as t ² and is much larger than ? ²/4. For one classical part, the left-hand side of the corresponding relation goes to the right-hand side equal to ? ²/4. For no classical part, both the right-hand and left-hand sides of the corresponding relation go quickly to zero. Therefore, the well-known limitations following from the usual uncertainty relations can be overcome in the corresponding measurements.     

Synthesis and solution properties of a new pH‐responsive polymer containing amino propanesulfonic acid residues

The reaction of diallyl amine with 1,3‐propane sultone led to the synthesis of the zwitterionic monomer 3‐(N,N‐diallylammonio)propanesulfonate. The sulfobetaine was cyclopolymerized in water in the presence of sodium chloride with t‐butylhydroperoxide as an initiator to afford a polysulfobetaine (PSB) in very good yield. PSB, upon treatment with sodium hydroxide, was converted into an anionic polyelectrolyte (APE). Although APE was readily soluble in salt‐free water, PSB needed the presence of low‐molecular‐weight salts (e.g., NaCl, KI, etc., in the range of 0.135–1.04 N) for its dissolution. The solution properties of PSB and APE were investigated with potentiometric and viscometric techniques. The basicity constant of the amine was apparent and followed the modified Henderson–Hasselbalch equation; as the degree of protonation (α) of the whole macromolecule increases, the protonation of the amine nitrogens becomes increasingly more difficult. The composition and phase diagram of the aqueous two‐phase systems of APE/PSB and poly(ethylene glycol) were also explored. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 172–184, 2003     

Understanding the extraction mechanism,radiolytic stability and stripping behavior of thorium by ionic liquid based solvent systems: evidence of ‘ion-exchange’ and ‘solvation’ mechanism

The extraction efficiency for thorium followed the trend: Cyanex-923 > Cyanex-272 > DHOA > TBP. In case of TBP and DHOA the extraction proceeded via ‘solvation mechanism’ through Th(NO₃)₄·2L, while for Cyanex-923 and Cyanex-272 it proceeded via ‘ion exchange’ mechanism through (Th(NO₃)₂·2L)²⁺. The extraction process followed slower kinetics while change in Gibb’s energy revealed the spontaneity of the process. These ionic liquid based systems were found to be radiolytically stable, highly efficient and selective for Th. Oxalic acid was found to be suitable for almost quantitative stripping of Th from extracted ionic liquid phase.     

Growth of cerium tungstate epitaxial layers: influence of temperature

Thin films of cerium tungstate prepared in situ by cerium deposition in oxygen atmosphere onto the W(100) single‐crystal were investigated by means of photoelectron spectroscopy and low‐energy electron diffraction (LEED). The studied temperature range was 173–1073 K. It was found that the temperature necessary for the oriented growth of Ce₆WO₁₂(100) was 673 K, and at higher temperatures, the LEED pattern improved. Photoemission data revealed the partial formation of CeO₂ on the surface at preparation temperatures below 473 K due to limited diffusion of tungsten atoms from the substrate. Copyright © 2015 John Wiley & Sons, Ltd.     

Positive definite solution of a nonlinear matrix equation

Using fixed point theory, we present a sufficient condition for the existence of a positive definite solution of the nonlinear matrix equation \({X = Q \pm \sum^{m}_{i=1}{A_{i}}^*F(X)A_{i}}\), where Q is a positive definite matrix, A _i ’s are arbitrary n × n matrices and F is a monotone map from the set of positive definite matrices to itself. We show that the presented condition is weaker than that presented by Ran and Reurings [Proc. Amer. Math. Soc. 132 (2004), 1435–1443]. In order to do so, we establish some fixed point theorems for mappings satisfying (\({\psi, \phi}\))-weak contractivity conditions in partially ordered G-metric spaces, which generalize some existing results related to (\({\psi, \phi}\))-weak contractions in partially ordered metric spaces as well as in G-metric spaces for a given function f. We conclude, by presenting an example, that our fixed point theorem cannot be obtained from any existing fixed point theorem using the process of Jleli and Samet [Fixed Point Theory Appl. 2012 (2012), Article ID 210].     

Selective hydrogenation and Suzuki cross‐coupling reactions of various organic substrates using a reusable polymer‐anchored palladium(II) Schiff base complex

A new polymer‐anchored Pd(II) Schiff base complex has been prepared and characterized using scanning electron microscopy, elemental analysis, atomic absorption spectroscopy, TGA and spectrometric methods such as diffuse reflectance spectra of solid and FT‐IR spectroscopy. This polymer‐anchored palladium catalyst shows excellent catalytic activity in the liquid‐phase hydrogenation reaction of styrene oxide to obtain selectively 2‐phenylethanol at normal pressure of hydrogen gas (1 atm.) at room temperature in DMF medium. We have also studied the liquid‐phase hydrogenation reaction of various organic substrates. The catalyst exhibits excellent catalytic activity for the Suzuki cross‐coupling of various substituted and non‐substituted aryl halides. The influences of various parameters were investigated to optimize reaction conditions. The reusability experiments show that the catalyst can be used five times without much loss in catalytic activity. Copyright © 2012 John Wiley & Sons, Ltd.     

From finite to infinite crystals: Analytic solution of simple tight binding model of finite sc,fcc and bcc crystals of arbitrary size

The electronic structure of finite sc, fcc and bcc crystals having a rectangular parallelepiped geometry is investigated here. In all three cases, analytic formulae for the energies and wave functions are obtained. It is shown that the results for the fcc and bcc lattice in the tight binding first nearest neighbour approximation can directly be obtained from those for the sc lattice in the third nearest neighbour approximation. Further it is shown for the crystals in question that the concept of the Brillouin zone has a good meaning not only for the infinite crystals but also for the finite ones. The mutual relation of real and Born-Kármán boundary conditions and the transition finite-infinite crystal in both directions are investigated and discussed in detail.