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Ring polymer molecular dynamics (RPMD) is an accurate method for calculating thermal chemical reaction rates. It has recently been discovered that low-temperature calculations are strongly affected by the simulation parameters. Here, for the thermally activated reaction DH + H → D + H2, we calculate the RPMD rate constants at T = 50 , 100, and 300 K and demonstrate that for T ≥ 100 K the standard input parameters yield accurate results, but at low temperatures (e.g., 50 K) one must increase the asymptotic distance and force constant, and decrease the umbrella integration step.

Object. The article describes a new geological and geochemical data for Permian host rocks and copper sandstones (CS) in Orenburg’s Pre-Urals. Methods . X-ray fluorescence, atomic absorption for Au and Ag, and ICP-MS analysis were used during investigations. Results. The cupriferous sandstones are enriched in a quite broad range of microelements: Cu, Ag, Au, Cd, Сr, Ni, Mn, Co, V, U, Sc, and Pb, compared to the average values of the upper crust. The Co/Ni ratio in the CS is very low, which is typical of low-thermal fluids of meteoric origin. The CS are characterized by a REE spectrum without Eu-minima and maxima, which is close to the chondrite spectrum. Like in the host rocks, the “cerium” group of REE dominates in the CS over the “yttrium” and “scandium” groups. The spectra of REE of the CS and the host rocks have definitely similar morphology. The δCe and δEu combination indicates that CS was formed under oxidizing conditions. On geological and genetic characteristics and geochemical indicators installed the similarity of the CS in the southern Pre-Urals deposits and the Manto-type Cu-Ag deposits of Chile and Iran, and also with the CS of Iran and Cu-shales of Kupferschiefer. Conclusion. Proposed geological-genetic model of CS, points to possible high rise development of the Cu-Ag mineralization at depth as in the fields of the Manto-type copper deposits in Chile and Iran. Geochemical data show that accommodating the Permian strata could serve as a source of REE and other trace elements for ore-forming fluids. Perm CS of Pre Urals can be considered as a very promising new (“old”) source of raw materials for the development of the copper industry of the region. The obtained results can be used to predict new ore fields in the Eastern Russia region.

The most common cryopreservation protocols of biological tissues suitable for their further implantation has some disadvantages and limited to one sample per procedure with no possible repeated freezing in case of clinical needs. This study is aimed to improve a biological tissues cryopreservation by adding a new heat transfer fluid – polydimethylsiloxane (PDMS). To evaluate its efficiency the porcine biological tissues (heart valves, aortic and trachea fragments) were cryopreserved and thawed in low-viscous PDMS. According to the computer simulation, the midsection cooling rate was up to 490 °C/min and the midsection thawing rate was up to 1140 °C/min with admissible temperature uniformity. Cryoprotectants and liquid nitrogen were not used. The quality of tissue cryopreservation was evaluated using a number of histological and immunohistochemical methods (Orcein, H&E, Anti-CD34, Anti-Vimentin, Anti-Actin staining). Cryopreserved tissues showed no significant morphological difference in comparison with control group both in case of immediate thawing, and after 2 months of low temperature storage. Computer simulation of heat transfer showed the thermal limitations of used approach for larger specimens. The use of PDMS is proposed for preservation of vascular tissue in order to implant it in the form of homotransplants or biobanking with the possible additional use of an internal hydrophilic coating to prevent hydrophobization.

In this work, we have extended the method proposed by Gabel for the preparation of mono- and di-S,S-substituted derivatives of sulfanyl-closo-dodecaborate anion [B12H11SH]2− to derivatives of the closo-decaborate anion. The method is based on the β-elimination of the propionitrile group of sulfonium derivatives [BnHn-1S(R)CH2CH2CN]− in the presence of bases with the formation of the corresponding mono-S-substituted derivatives and acrylonitrile. We also calculated the Fukui functions for the nucleophilic attack of the S-atom in the [B10H9SH]2− and [B12H11SH]2− anions and their mono-S-substituted derivatives using the Hirshfeld approach. As a result, the calculated value of nucleophilicity in the [B10H9SH]2− anion was found to be 5–10 times lower than in other compounds, which completely agrees with the experimental data.

Simple Summary We found that incubation with a solution containing ~50 mM neodymium (one of the rare-earth elements, REE) induces a rapid of active metabolism in mammalian cells. We have named this state REEbernation and found that the process involves a rapid replacement of calcium with neodymium in membranes and organelles of a cell, allowing it to maintain its shape and membrane integrity under extreme conditions, including vacuum. Furthermore, phosphate exchange is blocked because of non-dissolvable neodymium salts formation, which “discharged” the cell. We also showed that REEbernation is characterized by instant shutting down RNA transcriptional activity in the cells, providing an intriguing opportunity to study a snapshot of gene expression at a given time point. Finally, we found that the REEbernation state is reversible, and we could restore the metabolism and proliferation capacity of the cells. The REEbernation provides a new method to reversibly place a cell into “on-hold” mode, opening opportunities to develop protocols for biological samples fixation with a minimum effect on the omics profile for biomedical needs. Abstract Until now, the ability to reversibly halt cellular processes has been limited to cryopreservation and several forms of anabiosis observed in living organisms. In this paper we show that incubation of living cells with a solution containing ~50 mM neodymium induces a rapid shutdown of intracellular organelle movement and all other evidence of active metabolism. We have named this state REEbernation (derived from the terms REE (rare earth elements) and hibernation) and found that the process involves a rapid replacement of calcium with neodymium in membranes and organelles of a cell, allowing it to maintain its shape and membrane integrity under extreme conditions, such as low pressure. Furthermore, phosphate exchange is blocked as a result of non-dissolvable neodymium salts formation, which “discharged” the cell. We further showed that REEbernation is characterized by an immediate cessation of transcriptional activity in observed cells, providing an intriguing opportunity to study a snapshot of gene expression at a given time point. Finally, we found that the REEbernation state is reversible, and we could restore the metabolism and proliferation capacity of the cells. The REEbernation, in addition to being an attractive model to further investigate the basic mechanisms of cell metabolism control, also provides a new method to reversibly place a cell into “on-hold” mode, opening opportunities to develop protocols for biological samples fixation with a minimum effect on the omics profile for biomedical needs.

The quality of electron microscopy (EM) visualization of biological objects is constantly improving, primarily with the usage of more complex technologies, such as serial block-face scanning electron microscopy (SEM), focused ion beam scanning electron microscopy, and array tomography. Here we suggest a new rapid method of whole cell sample preparation for scanning EM using neodymium chloride treatment followed by staining with lead acetate. This variant of sample preparation does not require separate fixation, complete dehydration, and metal sputtering. By means of SEM in the back-scattered electron mode, in the neodymium-treated preparations, we visualized various morphological structures in human cells (nuclei with nucleoli, cytoskeleton, mitochondria) and microbial cells (Staphylococcus epidermidis, Streptococcus pneumoniae, Escherichia coli, and Candida albicans) preserving their species-specific shape and size. Thus, the suggested method provides additional information combining capabilities of SEM in visualizing cellular surface and transmission EM in detecting intracellular structures. Moreover, biological sample preparation with neodymium and lead is fast, informative, and cost-saving indicating a potential for its practical use for environmental SEM, and can be effectively combined with optical microscopy.

Experimental investigations of the saturated vapour pressure of liquid Na-K, Na-Cs, K-Cs, Rb-Cs, and Na-K-Cs alloys were carried out at temperatures up to 1500 K. The measurements were made by both the classical static method and the static manometric method. The alloys were prepared by the weighing method and the error in concentration of their components is ′ 0.5 wt%. A statistical analysis of the results of the experiments was carried out. Their absolute error including systematic and random components did not exceed 1.5% at temperatures up to 1000 K and 1% at temperatures more than 1000 K. The approximated equations for the saturated vapour pressure of the above alloys in the studied temperature range were obtained by the least-squares technique. The root-mean-square deviations of experimental points from these equations are 0.5% at the maximum.