Performance Tests of HX340 Microalloyed Steel Sheets Joined Using Clinch-Rivet Technology.

This paper presents the possibility of forming a pressed joint between two 1.5 mm thick sheets made of HX340 steel. The joint was formed using an additional deformable steel rivet with a hardness of 400HV1.

Efficacy of oral amantadine among patients hospitalised with COVID-19: A randomised, double-blind, placebo-controlled, multicentre study.

Background: Amantadine has been proposed as a treatment for COVID-19 because it shows anti-SARS-CoV-2 activity in vitro. However, to date, no controlled study has assessed the safety and efficacy of amantadine in COVID-19.

Research Question: Whether amantadine is effective and safe among patients with different COVID-19 severity classifications.

Theoretical Study of Proton Tunneling in the Imidazole-Imidazolium Complex.

Proton tunneling in the hydrogen-bonded imidazole-imidazolium complex ion has been studied theoretically. CASSCF/6-311++G(d,p) calculations concerning geometry optimization and vibrational frequencies have been carried out for equilibrium and transition state structures of the system. Two-dimensional double-well model potentials were constructed on the basis of results and used to analyze the proton dynamics in the hydrogen bond and the influence of the excitation of low-frequency hydrogen-bond vibrations on the proton tunneling splittings.

Infrared Spectroscopy and Born-Oppenheimer Molecular Dynamics Simulation Study on Deuterium Substitution in the Crystalline Benzoic Acid.

In this study we present complementary computational and experimental studies of hydrogen bond interaction in crystalline benzoic acid and its deuterated and partially deuterated derivatives. The experimental part of the presented work includes preparation of partially deuterated samples and measurement of attenuated total reflection (ATR)-FTIR spectra. Analysis of the geometrical parameters and time course of dipole moment of crystalline benzoic acid and its deuterated and partially deuterated derivatives by Born-Oppenheimer molecular dynamics (BOMD) enabled us to deeply analyze the IR spectra.

Quantum-mechanical study of energies, structures, and vibrational spectra of the H(D)Cl complexed with dimethyl ether.

Interaction energies, molecular structure and vibrational frequencies of the binary complex formed between H(D)Cl and dimethyl ether have been obtained using quantum-chemical methods. Equilibrium and vibrationally averaged structures, harmonic and anharmonic wavenumbers of the complex and its deuterated isotopomer were calculated using harmonic and anharmonic second-order perturbation theory procedures with Density Functional Theory B3LYP and B2PLYP-D and ab initio Møller-Plesset second-order methods, and a 6-311++G(3d,3p) basis set. A phenomenological model describing anharmonic-type vibrational couplings within hydrogen bonds was developed to explain the unique broadening and fine structure, as well as the isotope effect of the Cl-H and Cl-D stretching IR absorption bands in the gaseous complexes with dimethyl ether, as an effect of hydrogen bond formation.

Theoretical study of proton tunneling in the excited state of tropolone.

Ab initio CIS/6-311++G(d,p) calculations of geometry and vibrational frequencies have been carried out in the A state of tropolone. The grids of potential energy surfaces along the coordinates of high frequency tunneling vibration and the low-frequency coupled vibration have been calculated. Two-dimensional model potentials, formed from symmetric mode coupling potential and squeezed double well potential, have been fitted to the calculated potential energy surfaces and used to analyze proton dynamics.

Theoretical modeling of the O-H stretching IR bands of hydrogen-bonded dimers of benzoic acid in S(0) and S(1) electronic states.

Theoretical model for vibrational interactions in the hydrogen-bonded dimer of benzoic acid is presented. The model takes into account anharmonic-type couplings between the high-frequency O-H and the low-frequency O[cdots, three dots, centered]O stretching vibrations in two hydrogen bonds, resonance interactions (Davydov coupling) between two hydrogen bonds in the dimer, and Fermi resonance between the O-H stretching fundamental and the first overtone of the O-H in-plane bending vibrations. The vibrational Hamiltonians and selection rules for the C(2h) geometry in the S(0) state and for the C(s) in-plane bent geometry in the S(1) state of the dimer are derived.

Theoretical model of infrared spectra of hydrogen bonds in molecular crystals and its application to interpretation of infrared spectra of 1-methylthymine.

A theoretical model for vibrational interactions in the hydrogen bonds in molecular crystals with four molecules forming two centrosymmetric dimers in the unit cell is presented. The model takes into account anharmonic-type couplings between the high-frequency N-H(D) and the low-frequency N..

Theoretical model for a tetrad of hydrogen bonds and its application to interpretation of infrared spectra of salicylic acid.

Theoretical model of vibrational interactions in hydrogen-bonded salicylic acid dimer is presented which takes into account the adiabatic couplings between high- and low-frequency O-H and O...

Theoretical modeling of infrared spectra of hydrogen-bonded crystals of salicylic acid.

A theoretical model for the infrared spectra in the O-H stretching region of hydrogen-bonded salicylic acid is presented. Based on the model, infrared spectrum in the O-H stretching region is calculated for salicylic acid and compared with the experimental one. The experimental and theoretical spectra are in good agreement.

[Unstable angina pectoris associated with surgically treated coronary artery atresia].

A case report of a rare, presumably congenital form of "single coronary artery", is presented. The authors review the classification and clinical significance of the entity with special emphasis with regard to anginal symptoms and the so called sudden unexpected death syndrome. Details and result of surgical intervention (conventional aorto-coronary saphenous bypass) are discussed.