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Transfer functions for reconstruction of the duration of ice-free period at stations in the Chukchi, East Siberian and Laptev seas have been developed by comparison of hydrometeorological data and the chemical composition of bottom sediments accumulated during observation period. It has been established that in addition to the previously discussed processes through which the ice cover affects the chemical composition of bottom sediments (primary bioproductivity and redox conditions of bottom waters), there are several mainly local processes developed on the East Siberian shelf. These are the changes of terrestrial aqueous and solid runoff; coastal abrasion rate; current structure and water exchange through the Bering Strait between the Pacific and Arctic oceans; and intensity and direction of the ice/iceberg rafting of sediments. It is shown that some typical elements (Br, Ca, As, Fe, Ga) can be used as universal geochemical proxies for qualitative reconstruction of ice conditions.

The first description of well-preserved fur of one male and one female cubs of the fossil cave lion Panthera spelaea (finds of 2017-2018, Semyuelyakh River, Yakutia, Russia) is presented in comparison with the fur of two cubs (a male and a female) of the extant African lion P. leo and adult lions of both species: the color, differentiation, configuration, microstructure, and internal design of hair of different categories are considered. The coat of the cave lion is similar but not identical to that of the African lion, because it contains a high thick undercoat of spiral-shaped thick and airy down hair. This difference is most pronounced in the cave lion cubs, in which, however, the fur is not differentiated to the same extent as in the adult. The microstructure of hair is species-specific and subject to intraspecific age-related variability. Adaptive features of the hair structure in the cave lion are noted.

We report on the results of experiments on straining of aluminum and its alloys in conditions of mechanical loading and high temperatures. It is established that deformation accumulates in such conditions as a monotonic and abrupt process accompanied by monotonic and pulsed acoustic emission. It is found that the main contribution to strain accumulation comes from deformation jumps accompanied with not only acoustic emission, but also mechanical stress oscillation. The mechanical stress oscillation indicates rapid processes of strengthening and softening of metal materials. Spectral analysis of a series of acoustic emission signals indicates that in the course of strain accumulation, the volume being deformed is a natural resonator in which primary acoustic emission signals are transformed into a low-temperature spectrum of standing acoustic waves executing the correlation of elementary deformation events on a macroscopic scale, where the correlation scale is determined by the wavelength of a standing wave.

Various aspects of the seasonal and interannual variability of the sea ice cover are estimated based on all available Bering Sea ice data from 1960 to 2017. The possibility of long-term and super-long-term modeling of the ice cover is investigated. Test results are given, and a conclusion is drawn on the prospects of the proposed model and possibility of its practical application.

For the first time, the reconstruction of variations in the duration over several hundred years was conducted on the basis of models developed by comparing hydrometeorological observations and detailed scanning of the chemical composition of bottom sediments accumulated during the corresponding period. The gauge models for the reconstruction of air temperature and ice cover of the water area for three sites in the northern part of the Chukchi Sea have been developed. During the reconstruction, an insignificant increase in the duration of the ice-free period during the Little Ice Age was established, which does not coincide with the changes in the temperature regime that took place. It is concluded that the dynamics of the inflow of warm Pacific waters through the Bering Strait had the predominant influence on the ice regime of the Chukchi Sea.

The dark process (posteffect) of increasing the electrical conductivity and spectral absorption in the graphene oxide (GO) film after its preliminary UV irradiation has been studied. The posteffect is due to the conformational relaxation of the structure (flattening) of GO nanosheets after the UV-induced dissociation of oxygen-containing groups. At room temperature, the relaxation time is τ ≈ 300 h and the activation energy in the range of 20–70°C is E a ≈ 0.6 eV.

Thiacarbo- and thiadicarbocyanine indolenine and thiazoline polymethine dyes form host‒guest complexes with cucurbit[7,8]urils in water. Cucurbit[7]uril forms preferentially 1: 1 and 1: 2 monomeric complexes and cucurbit[8]uril forms 2: 1 and 2: 2 dimeric complexes. On the basis of quantum-chemical calculations, the structure of monomeric and dimeric complexes has been suggested. The complexation manifested itself in absorption, prompt and thermally activated delayed fluorescence spectra, as well as in the triplet‒triplet absorption spectra. Dimeric complexes in the triplet state are involved in one-electron oxidation and participate in triplet‒triplet energy transfer.

Spectral properties of inclusion complexes of cucurbit[7]uril (CB[7]) with styryl dye dications containing N-ammonioalkyl substituents of various length (D1, D2, D3) in water have been studied. The optimized structures of these complexes calculated by DFT methods made it possible to correlate the observed effects with the position of the nitrogen atom of the pyridinum residue of styryl dyes with respect to the CB[7] cavity. The bathochromic shifts of long-wavelength absorption bands for the inclusion complexes of D1 and D2 and the absence of such a shift for D3 are caused by structural distinctions between the inclusion complexes.

Spectral, luminescent and time-resolved characteristics of 2,5-dibenzylidenecyclopentanone and its symmetrical derivatives (bis(N,N-diethylamino-), dimethoxy-, tetramethoxy-, dimethylthio-, and bis-18- crown-6 derivative) have been studied in media of different polarity (cyclohexane, toluene, acetonitrile, DMSO, and methanol) at room temperature. The absorption maximum of dibenzylidenecyclopentanone shifts bathochromically by 15 nm with an increase in polarity of the medium (cyclohexane–methanol). The introduction of electron-donating substituents in the aromatic rings of dibenzylidenecyclopentanone also results in a bathochromic shift of the absorption maximum by 100–130 nm in the media of different polarity and shifts the fluorescence maximum by 130 nm relative to the maximum of the dimethoxy derivative. Upon laser irradiation of oxygen-free solutions of dibenzylidenecyclopentanone and its tetramethoxy- and bis-18-crown-6 derivatives in acetonitrile, the triplet state with a half-life time of 0.3–1 μs is generated. For dimethoxy-, dimethylthio-, tetramethoxy-, and bis-18-crown-6 derivatives of dibenzylidenecyclopentanone, the isomers with a lifetime of ~50 ms are formed.

Photoinduced processes in bis(diethylaminobenzylidene)cyclohexanone (CH1) and its bis(aza-18-crown-6) derivative (CH2) in acetonitrile at ambient temperature and 77 K have been studied. The absorption, fluorescence, and phosphorescence spectra of CH1 and CH2 are similar. The probability of the formation of the triplet state is higher for CH2 molecules (λT-Tmax = 660 nm, lifetime τT ~ 20 μs). The lifetime of the CH1 molecule in the triplet state is estimated at τT ~ 2–3 μs. Photoisomers of CH1 and CH2 are formed along with the triplet state. According to DFT calculation results, the formation of trans–cis photoisomers of CH1 and CH2 is the most energetically favorable.

An analysis of the available data on the various adaptations of the woolly mammoth to the cryoarid conditions of the Ice Age is presented. Mammuthus primigenius had a set of specific anatomic–morphological (thick long three-row wool, small ears, a short tail, an adipose “hump”, a “hood”-like extension on the trunk, and wide soles of the feet) and physiological (reduced sensitivity to cold and a specific kind of lipid metabolism) ideoadaptations that provided safe existence and wide distribution of this species in the Northern Holarctic for a long time. The current data make it possible to refer the woolly mammoth to a highly specialized species of the Mammoth biome.

This paper considers the data on new findings of mammoth fauna remains in the Middle Lena basin used to specify the species composition of large Late Neopleistocene mammals represented by eleven species. The obtained range of radiocarbon dates made it possible to state that mass burials of Pleistocene mammal remains were formed in the region during the Karginsk Interstadial (24 000-55 000 years ago).

The paper presents the first morphological description of the internal organs of a frozen corpse of the steppe bison Bison priscus (Bojanus, 1827) from the Holocene of northern Yakutia. Necropsy revealed that most of the internal organs, including the brain, heart with the main vessels, and reproductive system were well preserved. It demonstrated that the anatomy of this bison was close to that of the genera Bos and Bison. Trauma or pathological changes in the organs were not detected. The cause of death of the bison remains unknown.

Experimentally revealed features of thermal and photochemical deoxidation of graphene oxide (GO) in films are reported. A difference in mechanism between the photoreduction and thermal reduction of GO has been shown. The mechanism of photochemical deoxidation of graphene oxide has been rationalized using the concepts of molecular photochemistry. A new model of photoelimination of molecular oxygen from epoxy groups on graphene nanosheet has been proposed. The photoprocesses lead to growing of π-domains of graphene.

Photoprocesses in bis(diethylaminobenzylidene)cyclopentanone (D1) and its bis(aza-18-crown-6) derivative (D2) have been studied in acetonitrile. The absorption, fluorescence, and phosphorescence spectra of D1 are similar to those of D2. Laser excitation of oxygen-free solutions of D1 and D2 leads to generation of a triplet state with a lifetime of ∼1 μs and two intermediate species with lifetimes of ∼100 μs and longer than 1 s.

The mechanism of formation of triplet excited states of molecular systems in photonics and radiation chemistry has been considered. Intersystem crossing processes, two-photon excitation of high triplet states, and their evolution are discussed. The specific features of the formation of triplet states in radiation chemistry have been considered. Examples of using the concepts of triplet states in various fields, such as molecular luminescence, photochemistry, radiation chemistry, photodynamic therapy, design of organic light-emitting diodes, and information recording, are presented.

A well-preserved trunk (proboscis) of the woolly mammoth (Mammuthus primigenius) found in 2010 in the area of the Oiyagosskii Yar, about 30 km west of the mouth of the Kondratievo River (Yakutia) is described (mammoth named Yuka). The distal part of trunk has a transverse expansion. In the expanded condition, it changes the trunk cross section from oval to ellipsoidal. The expansion is laterally framed by skin folds with sites of muscles making the trunk cross diameter twice as great. Trunk expansion has been recorded in three mammoths: Yuka, Kolyma mammoth, and Kirgilyakh mammoth calf. Structural details of the trunk expansion of the Kirgilyakh mammoth calf and Yuka are almost completely identical. This morphological feature distinguishes trunk of M. primigenius from Loxodonta africana and Elephas maximus ones, the cross section of which remains oval throughout the trunk extent. The adaptive value of this unique trunk structure of the woolly mammoth in connection with cold climate conditions is discussed.

We have analyzed the electrocaloric response in ferroelectric materials in nonequilibrium thermal conditions. The temperature dependences of the electrocaloric response during polarization and depolarization of ferroelectric samples based on solid solutions of barium–strontium titanate and lead magnoniobate–titanate are considered. The difference in the electrocaloric responses for polarization and depolarization, which can be as large as 5 mK, has been demonstrated experimentally.

Energies of electronically excited states of a number of aromatic azides have been calculated using ab initio quantum-chemical methods. It has been shown that the relative arrangement of the singlet and triplet states of the A′ and A″ types changes with an increase in the number of π electrons in the system. As in the case of other classes of heteroaromatic molecules, five relative locations of these states are possible. On this basis, the dependence of the luminescent and photochemical properties of molecules of aromatic azides on their chemical structure has been rationalized.

Theoretical concepts of molecular photonics are presented. Features of the photophysical processes in molecular systems and the relationship between their probability and the electronic structures of the molecules are discussed. Possible mechanisms for the photochemical decomposition of electron-excited molecular systems with chemical bond cleavage are considered. The effect adiabatic photochemical reactions have on the probability of nonradiative conversion processes is shown. Dependences of spectral luminescence properties, the photochemical and radiation chemical stability of the molecular systems, and the efficiency of molecules of photostabilizers of polymers on their structure are interpreted. Areas of application are indicated for molecular photonics.

The exterior, skeletal morphology, and teeth of a 4- to 5-month-old woolly mammoth calf, Mammuthus primigenius Proboscidea, Elephantidae from the Khroma River (Yakutia, Russia) are described. This is the third and best preserved frozen carcass of the mammoth calves from Yakutia. The calf is male (penis available). The individual age as determined by the degree of wearing of DP2 and the beginning of wear of DP3 corresponds to the stage of transition to combined feeding (milk and vegetal forage). At the same time, formation of the cranial sutures (sutura sagittalis, fronto-temporalis, squamo-temporalis, and the suture between os occipitale superior and os occipitale inferior) testifies to an older juvenile stage. The proximal and distal epiphyses of the humerus and the distal epiphysis of the femur are represented by paired centers of ossification. A comparison of the dimensions of the head, body, and legs with the corresponding parameters of other M. primigenius calves of the same age shows the individual variability (10–15%) of these features. Although of medium size characteristic of M. primigenius calves, the described individual lacks subcutaneous fat deposits in the withers and subdermal areas of the body flanks. Death was caused by a rupture of the body and vertebral column at the level of the pectoral vertebrae 11–12. The deformation of the legs and longitudinal stretching of the soft tissues of the body caused no bone fractures (except for three ribs in the zone of the rupture). The long bones are not dislocated either in the shoulder and pelvic girdles or relative to each other. Possible causes and the timing of the death of the mammoth calves preserved in the permafrost are discussed.

The mechanisms of dissociation of oxygen-containing moieties (-OH, -HCO, -COOH) upon the photoreduction of graphite oxide by UV light have been considered. It has been concluded that the photoreduction, which involves the detachment of the OH group and the molecular elimination of CO and CO2, occurs in singlet excited states. The energy threshold of the photoreduction processes is determined by the position of the repulsive terms of the system.

The glass surface has been modified by titanium dioxide films synthesized using the sol-gel method. The sol-gel synthesis has been optimized by the experimental design with the use of the Latin square method. The film composition has been evaluated using X-ray powder diffraction analysis and optical measurements. The photoinduced hydrophilicity of the modified glass has been investigated.

A review of two-photon photoprocesses of polyatomic molecules in the condensed phase is presented. The mechanism and the kinetics of absorption of the second photon of light are discussed, as well as the features of the main two-photon processes (ionization, electronic excitation energy transfer, dissociation with abstraction of hydrogen atoms and molecular products). The research capabilities of the method are demonstrated. It is emphasized that one of the main requirements to molecules of effective light stabilizers for polymers is the absence of two-photon processes for these molecules, which is provided by the nonradiative conversion processes initiated by reversible adiabatic reactions. On this basis, interpretation of the properties of the main classes of light stabilizers for polymers is given.

Complex (experimental and quantum-chemical) investigation of the spectral and luminescent properties of acridine, 9-aminoacridine, 2,7-dimethyl-9-ditolylaminoacridine, and their protonated forms was performed. The electronic absorption and fluorescence spectra of the acridine dyes were studied at room temperature in ethanolic solutions at different pH values and in other solvents of different chemical nature and polarity. The energies of the excited states, the deactivation rate constants for the excited states, and the dipole moments are presented, which were obtained by calculations using the method of intermediate neglect of the differential overlap with special spectroscopic parameterization.

The effect of intermolecular interactions of different types (universal interactions, H-bonding, electronic donor-acceptor interactions, and interactions with proton transfer) on the absorption and luminescence spectra of organic molecules of different classes, which are or can be used as optical molecular sensors, was considered. The classification of the types of intermolecular interactions and corresponding spectroscopic effects is given, which can be used, particular, in the development of optical sensors for detection of organic molecules in liquid and gaseous media.

The main concepts of the nature of electronically excited states in polyatomic molecules and the intramolecular and intermolecular processes of their evolution are reported. The dependence of the probabilities of these processes on the electronic structure of the molecule is considered. Possible mechanisms of the dissociation of electronically excited molecules with bond cleavage are discussed, and the theoretical results of this consideration are given. The experimental data obtained by the authors are interpreted. In this case, attention is focused on C-H-bond photodissociation processes in a condensed phase, which are the best studied processes. The dissociation of other bonds is briefly discussed.

triplet state is short. This significantly distinguishes energy transfer involving T* states from energy trans� fer involving the longlived triplet state Т1. The proba� bility of intermolecular Т-Т transfer is determined by exchange electron interaction (5), and it decreases exponentially with an increase in the distance between the energydonor and energyacceptor molecules. According to (1), the average distance of energy trans� fer from the high triplet state of octadeuterionaphtha� lene to toluene is ~6 A. In this work, we put forward an idea that the high efficiency of energy transfer from high triplet states observed in some systems is mainly due to formation of exciplexes between the energy donor and acceptor. The efficiency of energy transfer from high triplet levels of the donor molecule to acceptor molecules, which are usually solvent (matrix) molecules, is char�

Frost resistance of winter barley (Hordeum vulgare L.) cultivars was found related to water retention capacity (hygroscopicity) of mature grain. With an example of 17 cultivars, it was shown that the higher is frost resistance the lower is the volume of supernatant liquid extracted from ground barley grains with a magnesium salt solution. Comparative assessment of frost resistance from the freezing survival of whole plants in refrigerating chambers and from hygroscopicity of mature grain has shown that these two methods produce similar data. At the same time, the proposed new method of assessing frost resistance is considerably simpler and economically more efficient than the method of whole plant freezing.

The development of nanocrystalline phases during isothermal annealing of titanium dioxide films deposited by reactive magnetron sputtering at various rates onto silica glass substrates has been studied. It is established that the heat treatment at temperatures within 500–700°C in air or in vacuum leads to significantly different results, depending on the initial crystalline structure of as-deposited films.

The behavior of the quantum yield of the photochemical processes occurring in polyatomic impurity molecules incorporated in a photonic crystal and its dependence on the relative position of the band gaps of the crystal and the energy of low-lying excited states of a molecule are discussed. Provided that the energy of the low-lying singlet photoactive state of a molecule is in the crystal band gap, an increase in the quantum yield of a photochemical reaction over its value in standard solutions must be observed. The processes of isomerization, dissociation, proton transfer, and oxidation are among these reactions. Examples of systems where the manifestation of this effect should be expected are given. The reactions that occur in the low-lying and high-lying triplet states, which are initiated by two-phonon excitation, and those sensitized upon the intermolecular transfer of electronic excitation energy are discussed.

Classical anisotropic cosmological models are described in terms of the Raychaudhuri equation for a perfect fluid. Quantum ones are considered using the Wheeler-DeWitt equation. The Universe birth probability has been calculated for a flat model with dust and de Sitter vacuum.