Simulation of collision-induced absorption spectra based on classical trajectories and ab initio potential and induced dipole surfaces. II. CO2-Ar rototranslational band including true dimer contribution.

This paper presents further development of the new semi-classical trajectory-based formalism described in Paper I [Chistikov et al., J. Chem. Phys. 151, 194106 (2019)]. We report the results of simulation and analysis of the low-frequency collision-induced absorption (CIA) in CO2-Ar, including its true dimer component. Our consideration relies on the use of ab initio intermolecular potential energy and induced dipole surfaces for CO2-Ar calculated in an assumption of a rigid CO2 structure using the CCSD(T) method. The theory, the details of which are reported in Paper I [Chistikov et al., J. Chem. Phys. 151, 194106 (2019)], permits taking into account the effect of unbound and quasi-bound classical trajectories on the CIA in the range of a rototranslational band. This theory is largely extended by trajectory-based simulation of the true bound dimer absorption in the present paper. The spectra are obtained from a statistical average over a vast ensemble of classical trajectories restricted by properly chosen domains in the phase space. Rigorous classical theory is developed for two low-order spectral moments interpreted as the Boltzmann-weighted average of the respective dipole functions. These spectral moments were then used to check the accuracy of our trajectory-based spectra, for which both spectral moments can be evaluated independently in terms of specific integrals over the trajectory-based calculated spectral profiles. Good agreement between the spectral moments calculated as integrals over the frequency domain or the phase space largely supports the reliability of our simulated CIA spectra, which conform with the available microwave and far-infrared observations.

Seroprevalence and B1 gene genotyping of Toxoplasma gondii in farmed European mink in the Republic of Tatarstan, Russia.

Toxoplasma gondii is a protozoan parasite that infects almost all species of mammals and birds, including fur-bearing animals. However, the prevalence of T. gondii among Russian fur-bearing animals is unknown. In this study, the seroprevalence of T. gondii in European mink in Russia was investigated. In total, 100, 119 and 61 serum samples were collected from a fur farm, located in the Republic of Tatarstan, Russia, in autumn 2016, 2017 and 2018, respectively. The seroprevalence of T. gondii in 2016, 2017 and 2018 was 32% (23.2%-42.2%, 95% confidence interval [CI]), 31.1% (23.1%-40.3%, 95% CI) and 41.0% (28.8%-54.3%, 95% CI), respectively. In total, 50 brain samples from 100 animals whose blood was sampled in 2016 were analyzed by PCR to detect T. gondii DNA. T. gondii DNA was detected in 14% (7/50) of the mink brain samples. To examine single nucleotide polymorphisms (SNPs) in the partial B1 gene, we sequenced an 836-bp fragment, which contains a few SNPs, from the detected T. gondii DNA. The sequences of the fragments were identical to those of two of the major lineages, Type II and Type III, but differed from that of the Type I lineage.

Simulation of collision-induced absorption spectra based on classical trajectories and ab initio potential and induced dipole surfaces. I. Case study of N2-N2 rototranslational band.

This paper presents theoretical formalism and some results of the collision-induced absorption (CIA) spectral simulation based on the classical trajectory analysis. Our consideration relies on the use of ab initio potential energy and dipole moment surfaces for two interacting rigid monomers. Rigorous intermolecular Hamiltonian is represented and used in the body-fixed reference frame. The complete set of dynamical equations with Boltzmann-weighted initial conditions is solved to render a large number of classical trajectories. The spectral shape is calculated as an ensemble-averaged Fourier spectrum issued from the time-dependent induced dipole along individual scattering trajectories. Considering a pair of N2 molecules as an example, we have calculated the rototranslational CIA band profiles at T = 78, 89, 109, 129, 149, 179, 228, 300, and 343 K. The classical trajectory-based spectral shape was corrected to satisfy the quantum principle of detailed balance. Good accuracy of our semiclassical approach was demonstrated by comparison with available experimental data as well as with results of the previously published purely quantum simulation by Karman et al. [J. Chem. Phys. 142, 084306 (2015)] in which the same ab initio calculated N2-N2 potential energy and induced dipole moment surfaces were used.

Comprehensive classical analysis of partition function and some observables for weakly interacting polyatomic dimers.

This paper presents the systematic classical consideration of a statistical averaging procedure that permits the calculation of partition function, equilibrium constant, and some observables for polyatomic dimers composed of weakly interacting rigid monomers. It was shown that the number of independent internal coordinates in a body-fixed frame is a crucial parameter that largely determines the temperature dependence of the partition function irrespective of the kinematic coupling within various degrees of freedom. The kinetic energy was derived for the molecular pair of arbitrary complexity in the body-fixed frame. Rigorous expression was obtained for the partition function over a pre-selected domain in the phase space. A similar expression was applicable to perform statistical averaging of some observables. Taking a linear molecule-atom as an example, it was shown how the suggested general approach permits the calculation of the equilibrium constant for true bound dimer formation or zeroth spectral moment of a collision-induced absorption band.

A technique of hand digit reconstruction using scarred and deformed donor segments.

BACKGROUND: Hand digit reconstruction with transposition of hand segments in cases of hand injury is not used frequently by surgeons, at least in part because of potential ischemic complications after cicatricial changes in tissues. The aim of this study was to investigate the opportunities for expanding the set of indications for hand digit reconstruction using scarred and deformed donor segments. METHODS: We developed a technique of ischemic preconditioning and preforming the segment before transfer to improve macro-circulation and micro-circulation in scarred donor segments with a view to preventing ischemic complications in reconstructed digits. It was validated using clinical, radiological, morphological, and biophysical (IR imaging, laser Doppler flowmetry, rheovasography) methods. RESULTS: A total of 184 patients were included. Primary digit reconstruction was performed in 19 patients while secondary reconstruction-in 165 patients. Single-stage transfer was performed in 122 hands, delayed transfer-in 67 hands. The total number of reconstructed thumbs and fingers was 203. Digit viability, stability, mobility and range of motion were very good with the use of new technique. CONCLUSIONS: When transferring hand segments with severe and highly severe deformations, tissue scarring and vascular damage, it is beneficial to pre-train the donor segment against hypoxia by both exsanguination and surgical methods.

The estimation of total petroleum hydrocarbons content in waste water by IR spectrometry with multivariate calibrations.

Alkanes, cycloalkanes and arenes have rather different sensitivities to IR-spectrometric determination, leading to high relative uncertainty (δc) for the total petroleum hydrocarbon index (TPH) in natural and waste waters. Another source of TPH uncertainty is the mismatch of group composition of the hydrocarbon mixture in the sample and in the standard substance used for one-dimensional calibration. Increasing the number of wavelengths and using of multivariate calibrations permit the reduction of δc to <10% rel. These calibrations may be constructed from IR-spectra and findings of extracts from aqueous solutions with known content of hydrocarbons. The method takes into account the losses of hydrocarbons during sample preparation. The accuracy of TPH estimations for this method is much better than for standard methods based on one-dimensional calibration with Simard mixture. This new method is useful in produced waste water analysis.

Application of Ilizarov device for transfer of deformed digits, digital stumps, and metacarpal stumps.

PURPOSE: Digital transfer on a pedicle comprising only the neurovascular bundle may lead to irreversible ischemia in cases of severe hand tissue scarring. Previously described methods of such a transfer are conditional on the donor stump's being longer than both the recipient stump and the reconstructed digit. The aim was to develop a method of transferring deformed digits and their stumps after prior distraction of both neurovascular bundles and cutaneosubcutaneous pedicles with the help of the Ilizarov device. METHODS: We performed 2-staged transfer of mutilated digits, digital stumps, or metacarpals using the Ilizarov device for stretching pedicles at the first stage and subsequent segment transfer. RESULTS: The method was applied in 65 patients, with 77 digits reconstructed in 67 hands. Segments were transferred on palmar or both palmar and dorsal pedicles containing lipocutaneous bridges and neurovascular bundles. In 67 of 77 cases, amputation levels of transferred stumps were roughly comparable to those of stumps reconstructed. X-ray length of reconstructed digits averaged 84.44 +/- 3.55 mm. Successful acceptance of transferred segments and complete or partial recovery of the hand grip was achieved in all cases. CONCLUSIONS: Use of the Ilizarov device enables the digital reconstruction of short digits, allows transferring various hand segments, including pathologically changed ones, and ensures success even in cases where the donor digit is too short to consider single-stage pedicle transfer.