Search

This study examines the suitability of the authigenic 10Be/9Be dating method to the dating of the deposits of an incising river, taking as an example the Nová Vieska river terrace, which accumulated during the neotectonic inversion of the Danube Basin (western Slovakia). The succession was formed by a wandering river with minor preservation of proximal floodplain muds. The frequent occurrence of mud intraclasts reflects significant input of eroded material from underlying, older successions. The ages of 13 authigenic 10Be/9Be dating samples formed three groups: (1) samples from below the base of the river terrace yielded dates of ~4.13–3.70 Ma (including uncertainties); (2) muddy intraclasts from the river terrace gave an age range of ~2.79–1.96 Ma; and (3) in situ muddy layers had ages in the range of ~1.91–1.39 Ma. The large mammal fossil assemblage from channel thalweg deposits yielded a biostratigraphic age of ~3.6–2.2 Ma, matching the age of intraclasts, and thus emphasising the redeposited origin of those fossils. The relatively wide range of authigenic 10Be/9Be dating ages is interpreted as a result of the redeposition of mud from older strata on three scales: decimetre‐scale intraclasts, millimetre‐scale rip‐up clasts mixed into the newly formed beds, and formation of two authigenic rims with different age and 10Be/9Be records around individual particles. Considering these observations, an age range of in situ layers of ~1.91–1.39 Ma is proposed as the depositional age of the river terrace, with the most probable age falling within the most recent part of this interval. The effect of redeposition is thus shown to be potentially limiting to the application of authigenic 10Be/9Be dating to incising rivers, and stands in marked contrast to aggrading river settings, where redeposition of older sediments is limited and the degree of 10Be/9Be variability is low. [ABSTRACT FROM AUTHOR]

International chronostratigraphic chart showing division of geological time and its numerical ages is regularly updated by the International Commission on Stratigraphy (ICS). The Slovak chronostratigraphic chart has not been updated since the end of the 1980s. This paper provides an overview of standard procedures for deriving Slovak terms; introduces Slovak translation of the latest version of International chronostratigraphic chart (v2021/10), and encourages the use of the new and/or updated chronostratigraphic terminology in all publications written in Slovak language. [ABSTRACT FROM AUTHOR]

The paper presents the results of geological research of the Podunajská rovina Flat (hereinafter Danubian Flat) in terms of stratigraphy of near-surface and surface sediments and palaeo-environmental changes in the period from the last interglacial period (Eemian, about 127,000 years BP) to the present. The period of Late Glacial to Holocene was studied in more detail because the climatic transition of the Last Glacial to postglacial had the greatest influence on the formation of the present natural environment, fauna and flora. In this context, the possibility of using isotopic analyses of oxygen and carbon from gastropods shells was also investigated in the reconstruction of palaeoclimatic changes and the natural environment in the past. Using the AMS 14C method, 24 samples from 16 localities dating from the Late Glacial to Holocene succession were dated. The observed age of dated samples by this method ranged from 135 ± 30 years BP to 14,410 ± 90 years BP. The OSL method of the studied profiles of 15 localities of the Danubian Flat territory dated 22 samples. The age of these dated samples ranged from 127,000 to 314 years BP. The time period from the Eemian Interglacial (i.e. the penultimate glacial period) to the present has been recorded. Both methods specified the stratigraphic position of fluvial and aeolian sediments in the area studied. Research shows that the climate has never been stable in the past. The alternation of climate cycles during the last (Weichselian) glacial was reflected in the formation of sediments, to which flora, fauna and naturally also human society responded. The article also highlights the importance and merits of the study of climate change by various scientific disciplines. Without an interdisciplinary approach to the study of climate change, it is not possible to detect, record and accurately interpret minor climate oscillations in the past. Knowledge of climate history and its impact on the natural environment and human civilization is therefore essential for the forecast of future climate change. [ABSTRACT FROM AUTHOR]

A preparative archaeological survey was carried out in Balcarka Cave in the Moravian Karst in 2007. As the original archaeological layer known from the research carried out by J. Knies from unique items from the Magdalenian Period were not found, sediments with numerous palaeontological finds were investigated. These finds were analysed from both the archaeological and natural science viewpoint. [ABSTRACT FROM AUTHOR]

Skin exposure to ultraviolet (UV) light evokes a complex stress response in keratinocytes. Keratin filament organization provides structural stability and mechanical integrity of keratinocytes. Involucrin is a transglutaminase substrate protein contributing to the formation of insoluble cornified envelopes. However, a more complex role for keratins and involucrin has been proposed, including the regulation of cell stress response. The aim was to evaluate modulations of keratin 1, 10 and involucrin expression in HaCaT in the light of the complex response of these cells to UV-B radiation, including effects on c-Jun and matrix metalloproteinase 1 (MMP-1) gene expression and production of interleukin (IL) 6 and 8. A UV-B (300±5 nm) dose of 10 mJ/cm(2) was selected since this dose resulted in a partial decrease in cell viability in contrast to higher UV-B doses, which induced complete cell death 48 h after treatment. The UV-B radiation induced significant expression of keratin 1 and 10 and decreased expression of involucrin. This was accompanied by increased expression of c-Jun and MMP-1 and IL-6 and IL-8 production. The data suggest that the expression of keratin 1, 10 and involucrin is modulated in HaCaT keratinocytes as a part of the complex stress response to UV radiation.

Stress-induced fibroblast senescence is thought to contribute to skin aging. Ultraviolet light (UV) radiation is the most potent environmental risk factor in these processes. An Epilobium angustifolium (EA) extract was evaluated for its capacity to reverse the senescent response of normal human dermal fibroblasts (NHDF) in vitro and to exhibit skin photo-protection in vivo. The HPLC-UV-MS analysis of the EA preparation identified three major polyphenol groups: tannins (oenothein B), phenolic acids (gallic and chlorogenic acids) and flavonoids. EA extract increased the cell viability of senescent NHDF induced by serum deprivation. It diminished connective tissue growth factor and fibronectin gene expressions in senescent NHDF. Down-regulation of the UV-induced release of both matrix metalloproteinase-1 and -3 and the tissue inhibitor of matrix metalloproteinases-1 and -2, and also down-regulation of the gene expression of hyaluronidase 2 were observed in repeatedly UV-irradiated NHDF after EA extract treatment. Interestingly, EA extract diminished the down-regulation of sirtuin 1 dampened by UV-irradiation. The application of EA extract using a sub-irritating dose protected skin against UV-induced erythema formation in vivo. In summary, EA extract diminished stress-induced effects on NHDF, particularly on connective tissue growth factor, fibronectin and matrix metalloproteinases. These results collectively suggest that EA extract may possess anti-aging properties and that the EA polyphenols might account for these benefits.