Selected examples of natural stones from Italy and Germany used in architectural objects in Krakow – a short geological excursion

The aim of the following paper is to propose a trip to selected sites in Kraków where decorative stones imported from Italy and Germany were used. The main types of stones are presented together with their commercial names, quarries, age and decorative values. Additionally, the author identified the regions in Italy and Germany from which stones were supplied. The most popular Italian decorative stones are the Carrara marbles quarried in the vicinity of Carrara and the “Ammonitico rosso” limestones extracted in the neighbourhood of Verona. Interesting are also porphyries from Trident, limestones from Brescia, travertines from Tivoli and granites and travertines quarried in Sardynia. In Germany large deposits of Upper Jurassic limestones are located in northern Bavaria (Franconia)

Evidence of bacteriogenic iron and manganese oxyhydroxides in Albian-Cenomanian marine sediments of the Carpathian realm (Poland)

The Albian and Cenomanian marine sediments of the Silesian and Tatric basins in the Carpathian realm of the Western Tethys contain ferric and ferromanganese oxyhydroxides, visible macroscopically as brown stainings. They coat calcareous bioclasts and mineral clasts, fill pore spaces, or locally form continuous, parallel microlayers, tens of micrometers thick. Light-microscope (LM) and scanning-electron-microscope (SEM) obser- vations show that the coatings contain elongated capsules, approximately 3-5 \mum across and enriched in iron and manganese, which may be remnants of the original sheaths of iron-related bacteria (IRB). Moreover, the ferric and ferromanganese staining observed under LM is similar to bacterial structures, resembling the sheaths, filaments and rods formed by present-day bacteria of the Sphaerotilus-Leptothrix group. All of the possible bacteria-like structures are well preserved owing to processes of early diagenetic cementation. If the observed structures are fossil IRB, these organisms could have played an important role in iron and manganese accumulation on the sea floor during Albian-Cenomanian time. The most plausible source of metals for bacterial concentration in the Silesian Basin might have been submarine low-temperature hydrothermal vents, as previously was hypothesized for Cenomanian-Turonian deposits on the basis of geochemical indices

Successive stages of calcitization and silicification of Cenomanian spicule-bearing turbidites based on microfacies analysis, Polish Outer Carpathians

Mid-Cretaceous turbidites with large proportions of sponge spicules are widely distributed in the Silesian Nappe of the Outer Carpathians, giving rise to diversified types of sediments, from spiculites to spicule-bearing siliciclastics and calcarenites. Part of this succession, Middle–Late Cenomanian in age, was transformed into cherts. A microfacies study showed that these turbidite sediments underwent several stages of calcitization and silicification, which took place during Mid-Cretaceous times in different sedimentary environments, i.e., on a northern shelf bordering the Silesian Basin and on a deep sea floor. The first diagenetic changes were related to changes to the biotic components of the turbidite layers, dominated by siliceous sponge spicules. This process, which took place in the spiculitic carbonate mud on the shelves, was related to the calcitization of sponge spicules. Calcareous clasts and calcified skeletal elements also were corroded by bacteria. After transportation down the slope, the biogenic and siliciclastic particles were deposited below the carbonate compensation depth. Taphonomic processes on the basin floor and alternating phases of carbonate and silica cementations, recrystallization and dissolution occurred in these sediments and were related to the diversification in composition of successive turbidite layers. Silicification was related to the formation of quartz precipitates as fibrous chalcedony or microcrystalline quartz, which were derived from the earlier dissolution of amorphous silica, originating mostly from siliceous sponge spicules and radiolarian skeletons. However, a source of silica from hydrothermal vents was also possible. The initial silica precipitation could have taken place in a slightly acidic environment, where calcite was simultaneously dissolved. A number of silicification stages, visible as different forms of silica precipitate inside moulds after bioclasts, occur in the particular turbidite layers. They were related to changes in various elements of the pore-water profile after descending turbidity-current flows. A very low sedimentation rate during the Middle–Late Cenomanian in the Silesian Basin may have favoured the sequence of initial calcitization and silicification stages of the turbidite sediments

Lithistid spicules in the sediments of the Turonian Variegated Shale in the Silesian Nappe, Polish Outer Carpathians

Turbiditic silty and sandy intercalations in the Turonian Variegated Shale from the Silesian Nappe (Polish Outer Carpathians) contain numerous sponge spicules among siliciclastic fine-grained particles. The highest amount of spicule admixture is nearly 50%. In such layers, they create spiculitic sublitharenite microfacies. These sponge spicules contain forms belonging mostly to the Lithistida group (97% of morphotypes), with a small admixture of spicules from the Hexactinellidae group. Tetraclones with a high content of different types of triaenes dominate among desmas, what indicates the dominance of sponges from subfamily Tetracladina. The preservation state of spicules is generally poor. The Variegated Shale deposits that contain the sponge spicules were accumulated in a deep sea basin, below the calcium compensation depth. Most probably, the spicules were derived from loose material accumulated earlier in various parts of the basin slopes, from which they were exhumed and again redeposited by turbidity currents during the Turonian times

Application of graphene as a nanoindenter interacting with phospholipid membranes - computer simulation study

Synthesis of graphene (GN) in 2004 stimulated wide interest inpotential applications of 2D materials in catalysis, optoelectronics, biotechnology,and construction of sensing devices. In the presented study, interactions betweenGN sheets and phospholipid bilayers are examined using steered moleculardynamics simulations. GN sheets of different sizes were inserted into a bilayer andsubsequently withdrawn from it at two different rates (1 and 2 m/s). In somecases, nanoindentation led to substantial damage of the phospholipid bilayer;however, an effective self-sealing process occurred even after significantdegradation. The average force and work, deflection of the membrane duringindentation, withdrawal processes, and structural changes caused by moving sheetsare discussed. These quantities are utilized to estimate the suitability of GN sheetsfor targeted drug delivery or other nanomedicine tools. The results are comparedwith those obtained for other nanostructures such as homogeneous andheterogeneous nanotubes

Steered molecular dynamics of lipid membrane indentation by carbon and silicon-carbide nanotubes - the impact of indenting angle uncertainty

Due to the semi-liquid nature and uneven morphologies of biological membranes, indentation may occur in a range of non-ideal conditions. These conditions are relatively unstudied and may alter the physical characteristics of the process. One of the basic challenges in the construction of nanoindenters is to appropriately align the nanotube tip and approach the membrane at a perpendicular angle. To investigate the impact of deviations from this ideal, we performed non-equilibrium steered molecular dynamics simulations of the indentation of phospholipid membranes by homogeneous CNT and non-homogeneous SiCNT indenters. We used various angles, rates, and modes of indentation, and the withdrawal of the relative indenter out of the membrane in corresponding conditions was simulated

The assessment of risk factors for febrile seizures in children

Objective The aim of the paper was to assess the risk factors of febrile seizures in children. Methods The paper presents an analysis of a group of 176 children aged 6 months to 5 years who were admitted to A&E because of febrile seizures. Results The analysed group of 176 children comprised 61.96% boys and 38.07% girls, and the average age equalled 23 months. Family history was significant in 9.66% of patients. A statistically significant difference was noticed between insignificant family history and the incidence of febrile seizures. In all the studied groups of children the factor that determined the incidence of febrile seizures was a sudden increase in the body temperature with an infection of the upper respiratory tract of several day's duration as another cause. Febrile seizure incident was most frequently associated with a sudden increase in the body temperature in 53.40% children. A statistically significant difference was observed between persisting fever and an increase thereof during the day. Yet another factor predisposing for febrile seizures incidence was an infection of the upper respiratory system that could be observed in 32.95% patients. The mean body temperature when the seizures occurred was 38.9°C. Conclusions A sudden increase in the body temperature within the first day of pyrexia predisposes for the incidence of febrile seizures and it was proved that it depends on how long fever persists during the day. The other factor triggering the seizures was an infection of the upper respiratory tract of several days’ duration

The assessment of risk factors for febrile seizures in children

Objective The aim of the paper was to assess the risk factors of febrile seizures in children. Methods The paper presents an analysis of a group of 176 children aged 6 months to 5 years who were admitted to A&E because of febrile seizures. Results The analysed group of 176 children comprised 61.96% boys and 38.07% girls, and the average age equalled 23 months. Family history was significant in 9.66% of patients. A statistically significant difference was noticed between insignificant family history and the incidence of febrile seizures. In all the studied groups of children the factor that determined the incidence of febrile seizures was a sudden increase in the body temperature with an infection of the upper respiratory tract of several day's duration as another cause. Febrile seizure incident was most frequently associated with a sudden increase in the body temperature in 53.40% children. A statistically significant difference was observed between persisting fever and an increase thereof during the day. Yet another factor predisposing for febrile seizures incidence was an infection of the upper respiratory system that could be observed in 32.95% patients. The mean body temperature when the seizures occurred was 38.9°C. Conclusions A sudden increase in the body temperature within the first day of pyrexia predisposes for the incidence of febrile seizures and it was proved that it depends on how long fever persists during the day. The other factor triggering the seizures was an infection of the upper respiratory tract of several days’ duration

Albumin-hyaluronan interactions : influence of ionic composition probed by molecular dynamics

The lubrication mechanism in synovial fluid and joints is not yet fully understood. Nevertheless, intermolecular interactions between various neutral and ionic species including large macromolecular systems and simple inorganic ions are the key to understanding the excellent lubrication performance. An important tool for characterizing the intermolecular forces and their structural consequences is molecular dynamics. Albumin is one of the major components in synovial fluid. Its electrostatic properties, including the ability to form molecular complexes, are closely related to pH, solvation, and the presence of ions. In the context of synovial fluid, it is relevant to describe the possible interactions between albumin and hyaluronate, taking into account solution composition effects. In this study, the influence of Na+, Mg2+, and Ca2+ ions on human serum albumin–hyaluronan interactions were examined using molecular dynamics tools. It was established that the presence of divalent cations, and especially Ca2+, contributes mostly to the increase of the affinity between hyaluronan and albumin, which is associated with charge compensation in negatively charged hyaluronan and albumin. Furthermore, the most probable binding sites were structurally and energetically characterized. The indicated moieties exhibit a locally positive charge which enables hyaluronate binding (direct and water mediated)

Influence of the molecular weight and the presence of calcium ions on the molecular interaction of hyaluronan and DPPC

Hyaluronan is an essential physiological bio macromolecule with di erent functions. One prominent area is the synovial fluid which exhibits remarkable lubrication properties. However, the synovial fluid is a multi-component system where di erent macromolecules interact in a synergetic fashion. Within this study we focus on the interaction of hyaluronan and phospholipids, which are thought to play a key role for lubrication. We investigate how the interactions and the association structures formed by hyaluronan (HA) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) are influenced by the molecular weight of the bio polymer and the ionic composition of the solution. We combine techniques allowing us to investigate the phase behavior of lipids (di erential scanning calorimetry, zeta potential and electrophoretic mobility) with structural investigation (dynamic light scattering, small angle scattering) and theoretical simulations (molecular dynamics). The interaction of hyaluronan and phospholipids depends on the molecular weight, where hyaluronan with lower molecular weight has the strongest interaction. Furthermore, the interaction is increased by the presence of calcium ions. Our simulations show that calcium ions are located close to the carboxylate groups of HA and, by this, reduce the number of formed hydrogen bonds between HA and DPPC. The observed change in the DPPC phase behavior can be attributed to a local charge inversion by calcium ions binding to the carboxylate groups as the binding distribution of hyaluronan and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine is not changed