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The microwear of the non-occlusal surface of incisors (I1, I2) of the small cave bear (Ursus ex gr. savini-rossicus) and Ural cave bear (Ursus kanivetz) from the Pleistocene of the Middle and South Urals is analyzed and compared. Qualitative characteristics of incisor microwear have been shown to be different in these species. In the small cave bear, coarser lesions on the non-occlusal surface of the incisors are observed. Considering the specificity of microwear of non-occlusal tooth surfaces, the data obtained suggest differences in trophic specialization of the species. studied., (© 2022. Pleiades Publishing, Ltd.)

Enamel macro- and microstructure has been studied in the teeth of Merck's rhinoceros (Stephanorhinus kirchbergensis Jäger, 1839), woolly rhinoceros (Coelodonta antiquitatis Blumenbach, 1799), and rhinoceroses from the Tetyukhinskaya (44°35' N, 135°36' E) and Sukhaya (43°09' N, 131°28' E) caves in southern Primorye. The teeth from the caves were identified as the teeth of Merck's rhinoceros. Radiocarbon dating and accompanying animal species enabled the dating of Merck's rhinoceros remains to the Late Pleistocene (marine isotope stages 5-2). These finds mark the extreme eastern boundary of the Merck's rhinoceros species range in the Late Pleistocene. The living range reached the Pacific Ocean coast during a certain time interval within this epoch. This was due to the abundance of tree and shrub vegetation in the area during the Late Pleistocene.

In small mammals, the degree of micro- and mesowear of molars depends on the feed hardness, abrasiveness, and some other characteristics. Analysis of micro- and mesorelief of the paleontological material is used for reconstruction of some animal diet parameters. Small mammals pass through a series of complex transformations on the way from the objects of biocenosis to paleontological objects. Bone remains underwent transformations during accumulation and fossilization. In particular, bone remains from ornithogenous deposits were exposed to the bird digestive system elements. We have experimentally studied changes in some parameters of the narrow-headed vole (Microtus gregalis) molars derived from the owl pellets. Comparison of the same samples before and after exposure to the digestive system of the polar owl (Nyctea scandiaca) and eagle owl (Bubo bubo) showed that the tooth enamel microrelief undergoes serious changes and therefore, provides no information on the intravital diet of voles. A different degree of preservation of the characteristics of the mesorelief was shown. Depending on this, an assessment of their applicability to paleoreconstructions was given.

In the narrow-headed vole, enamel microwear of the first mandibular molar (of the protoconid and entoconid anterior enamel wall) was studied under the laboratory conditions and at the fixed feed composition. The classic parameters and the area of the enamel prism lesion were taken into account. The enamel lesion patterns caused by the tooth-tooth and tooth-food interactions have been determined. Differences were found between the voles kept on feed with different abrasive properties, as well as between the lingual and buccal conids of the first mandibular molar. In the Microtus species, the ratio of micro-lesions (pits and scratches) did not depend on the abrasive properties of the feed consumed. The extent of preservation of the enamel contour anterior edge depended on the feed composition and could be used as an indicator for indirect evaluation of the Microtus species diet.

In Craseomys rufocanus and Craseomys rex, the age-related and species differences in thickness and microstructure of the first lower molars (ml) have been identified and studied. The results suggest that the enamel dimensional and microstructural features may serve as additional indicators of the vole tooth evolutionary stage within a single phyletic lineage.

Ontogenetic instability was studied in four rodent species (Ellobius talpinus, Microtus arvalis, M. rossiaemeridionalis, Mus musculus). It was measured by fluctuating asymmetry (FA) of 21 craniometric characters. Each species was represented by two populations differing in average level of chromosomic instability and in degree of anthropogenic influence. Relation between FA and individual age was observed in none of the studied species. The level of cranial structure FA in rodents is probably formed during embryogeny or early postnatal ontogeny and is not changing significantly during the further development. The studied species showed distinct differences in the degree of ontogenetic instability of the axial skull, but not of the mandible. No connection was found between craniometric character FA and technogenic stress. The differences of cranial FA level among the studied species of rodents agree with their systematic position and the sequence of their evolutionary divergence.

A scanning pH-microprobe was used to study pH patterns near the surface of Chara corallina cells at various light intensities and during light-induced transitions from homogeneous pH distribution to alternating pH bands. In the irradiance (PAR) range 4-400 micromol quanta m(-2) s(-1), the sustained pH profiles consisted of alternating acid and alkaline bands with a characteristic length of 7-10 mm and pH shifts as large as 2-3 units. At lower irradiance, the number of alkaline bands decreased while the amplitude of remaining peaks stayed high. On cyclic changes in light intensity, a hysteresis of pH banding was observed: the pH bands tolerated low irradiance in weakening light, but higher irradiance was required for their emergence after dark adaptation of the cell. The pH profiles measured for different paths of electrode scanning suggest that the pH pattern at low light level represents patches coexisting with bands. The exposure of the cell to high-intensity light led to formation of radially symmetrical bands. Transformations of the pH pattern induced by lowering the light intensity were similar to those induced by transcellular electric current (1.5-3 microA). The data suggest that band formation at the plasmalemma of Chara cells proceeds through the initial appearance of multiple patches with a localized H(+)-transporting activity and subsequent spot rearrangements (fusion, deletions, widening), leading to establishment of alternating bands.

When exposed to light, Characean cells develop a pattern of alternating alkaline and acid bands along the cell length. The bands were identified with a tip-sensitive antimony pH microelectrode positioned near one end of Chara internode at a distance of 50-100 microm from the cell wall. The stage with Chara cell was moved along its longitudinal axis at a computer-controlled speed (100 or 200 microm s(-1)) relative to the pH probe over a distance of 50 mm. Under sufficient uniform illumination of the cell (from 100 to 2.5 Wm(-2)), the homogeneous pH distribution becomes unstable and a banding pattern is formed, the spatial scale of which decreases with the light intensity. If the cell is locally illuminated, bands are formed only in the region of illumination. It is shown that the inhibition of cyclosis by cytochalasin B leads to the disappearance of the banding pattern. The addition of ammonium (weak base) inhibited the banding pattern, whereas acetate (weak acid) alleviated the inhibitory effect of ammonium and restored the pH banding. A model explaining the observed phenomena is formulated in terms of proton concentration outside and bicarbonate concentration inside the cell. It contains two diffusion equations for the corresponding ions with nonlinear boundary conditions determined by ion transport processes across the cell membrane. The model qualitatively explains most of the experimental observations. It describes the dependence of the pattern characteristics on the light intensity and reveals the role of cyclosis in this phenomenon.

The results of surgical treatment of 125 patients with perforative pyloroduodenal ulcer and wide-spread peritonitis were studied. Postoperative mortality was 3.2%. The method of cleansing and drainage of abdominal cavity was suggested, which allowed to avert the beginning of such severe complications as abscess and progressive peritonitis.

Overall 76 histories of births, case reports of neonates and protocols of autopsies of the dead because of infection were analyzed. It has been established that the overwhelming majority of the children had contracted infection antenatally or during birth, with the ascending pathway of infection being predominant. Attention is drawn to the clinical and postnatal diagnosis with the aid of the screening tests.