The 14-3-3 proteins are a family of acidicr egulatory molecules found in all eukaryotes. 14-3-3 proteins function as molecular scaffolds by modulating the conformation of their binding partners. Through the functional modulation of a wide range of binding partners, 14-3-3 proteins are involved in many processes including cell cycle regulation, metabolism control, apoptosis, and control of gene transcription. This minireview includes a short overview of 14-3-3 proteins and then focuses on their role in the regulation of two important binding partners: FOXO forkhead transcription factors and an enzyme tyrosine hydroxylase., V. Obšilová, J. Šilhan, E. Bouřa, J. Teisinger, T. Obšil., and Obsahuje bibliografii a bibliografické odkazy
Speleothems in 6 sandstone caves in the Bohemian Paradise (Český ráj) were dated by means of 14C and U-series methods. Stable isotopes of C and O, FAAS, IR, XRD, XRF and SEM were used to characterize the carbonate material and its source. Stable isotopes (C and O) composition of speleothems in two caves corresponds to values characteristic for cave speleothems in Central Europe. In other caves they indicate evaporation and fast carbon dioxide escape during carbonate precipitation. The speleothems from the Krtola Cave were deposited between 8 and 13 kyr BP. Speleothems were deposited 5-8 kyr BP in the Sintrová, Mrtvé Údolí and U Studánky caves. Calcite coatings on smooth sandstone surfaces in studied caves demonstrate that cave walls did not retreat even a few mm in the last 5-8 kyr since speleothem deposition and are thus not evolving under recent climatic conditions. Most of the cave ceilings and walls are at present time indurated by hardened surfaces, which protect the sandstone from erosion. Sandstone caves probably intensively evolved either during or at the end of the Last Glacial period. There are two different erosion mechanisms which might have formed/reshaped the caves at that time: A) In the case of permafrost conditions: Repeated freeze/melt cycles affecting sandstone pore space followed by the transport of fallen sand grains by minor temporary trickles. We expect that heat was transmitted by air circulating between the cave and the surface; B) Seepage erosion of sandstone during the melting of permafrost, prior forming of case hardening., Jiří Bruthans, Jana Schweigstillová, Petr Jenč, Zdeňka Churáčková and Petr Bezdička., and Obsahuje bibliografii
Our own study as well as others have previously reported that hypoxia activates 15-lipoxygenase (15-LO) in the brain, causing a series of chain reactions, which exacerbates ischemic stroke. 15-hydroxyeicosatetraenoic acid (15-HETE) and 15-oxoeicosatetraenoic acid (15-oxo-ETE/15-KETE) are 15-LO-specific metabolites of arachidonic acid (AA). 15-HETE was found to be rapidly converted into 15-oxo-ETE by 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in some circumstances. We have demonstrated that 15-HETE promotes cerebral vasoconstriction during hypoxia. However, the effect of 15-oxo-ETE upon the contraction of cerebral vasculature remains unclear. To investigate this effect and to clarify the underlying mechanism, we performed immunohistochemistry and Western blot to test the expression of 15-PGDH in rat cerebral tissue, examined internal carotid artery (ICA) tension in isolated rat ICA rings. Western blot and reverse transcription polymerase chain reaction (RT-PCR) were used to analyze the expression of voltage-gated potassium (Kv) channels (Kv2.1, Kv1.5, and Kv1.1) in cultured cerebral arterial smooth muscle cells (CASMCs). The results showed that the levels of 15-PGDH expression were drastically elevated in the cerebral of rats with hypoxia, and 15-oxo-ETE enhanced ICA contraction in a dose-dependent manner. This effect was more significant in the hypoxic rats than in the normoxic rats. We also found that 15-oxo-ETE significantly attenuated the expression of Kv2.1 and Kv1.5, but not Kv1.1. In conclusion, these results suggest that 15-oxo-ETE leads to the contraction of the ICA, especially under hypoxic conditions and that specific Kv channels may play an important role in 15-oxo- ETE-induced ICA constriction., Di Wang, Yu Liu, Ping Lu, Daling Zhu, Yulan Zhu., and Obsahuje bibliografii
Odlupováním vrstevnatých materiálů (např. grafitu) lze připravit 2D krystaly s tloušťkou jednoho nebo několika málo atomů. Nejznámějším takovým 2D materiálem je grafen (monovrstva grafitu), nicméně v současnosti existují a intenzivně se zkoumají desítky podobných struktur. Příspěvek podává základní přehled o 2D materiálech, jejich vlastnostech, metodách přípravy a možných aplikacích., Layered materials (such as graphite) can be exfoliated to produce 2D crystals with a thickness of one of just a few atoms. The best known 2D material is graphene (monolayer of graphite), yet there are tens of similar structures, which are being studied intensively at the moment. This article presents a brief summary of 2D materials, their properties, methods of preparation and potential application., Zdeňka Hájková, Martin Ledinský, Matěj Hývl, Aliaksei Vetushka, Antonín Fejfar, Jaroslava Řáhová, Otakar Frank., and Obsahuje bibliografické odkazy
Quaternary faulting in the western part of the Gulf of Corinth has been evidenced by geology and geomorphology, as well as by seismic recording. A series of three main normal fault segments are aligned in a steep southern coastal zone of the gulf. These fault segments, 15 to 25 km long, have an average strike of 90° - 105° and a northward dip of about 50° - 75°. Selected fault points were equipped with 3-D crack gauges TM71 during 2002 to monitor movements along the fault planes here, as well as on another fault cutting through the small island of Trizonia near the opposite northern shore of the gulf. Results of the monitoring present relative displacements induced by active tectonic movement s. Generally, the movements recorded on the faults are characteristic of an aseismic linear creep in vertical, i.e. upliftin g/subsiding in rates of mm per year due to uplifts of the Peloponnesian Peninsula. In 2003 a thr ee months long period of fast acceleration of movements was recorded. During this acceleration phase displacements changed to skew uplifting/subsiding with a left-lateral horizontal component. Moreover, horizontal rotation of monitored blocks corresponding to a sy stematic westwards opening of the Gulf was observed with only single eastward opening episodes., Josef Stemberk and Blahoslav Košťák., and Obsahuje bibliografické odkazy
During routine processing of selected events of an active KTB experiment it has appeared doubts concerning data reliability and consequently the reliability of results based on them. In the paper 3 events are studied in detail, full seismic moment tensors, as well as their errors, are determined (by non-linear inversion of P/SH waves ratios). It is shown that for the processed low constrained data moment tensor (MT) can be determined, however the relative error is of order of first tens of percent; the results also considerably depend on the way of data picking, used medium model, way of Cost function construction, etc. Any subsequent geophysical interpretation therefore should takes into account this uncertainty. MTs are finally decomposed into DC and non-DC parts, MTs errors are also transformed., Petr Kolář., and Obsahuje bibliografii
3D microscopy and image analysis provide reliable measurements of length, branching, density, tortuosity and orientation of tubular structures in biological samples. We present a survey of methods for analysis of large samples by measurement of local differences in geometrical characteristics. The methods are demonstrated on the structure of the capillary bed in a rat brain., J. Janáček ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
The present paper concerns long-term 3D monitoring of active fault structures in the Krupnik-Kresna seismic zone, SW Bulgaria with the use of extensometers TM71. The purpose is to establish the real rates of fault movements in the most seismically active area in Bulgaria. Three points were installed (B6 on Krupnik Fault, and K5 and K12 on Struma Fault), which indicate a recent activity. The fault movements are characteristic with “calm” periods, linear slips, accelerations and sudden displacements. Different regimes of dynamics have been established corresponding to different periods. The greatest dynamics is found at monitoring point B6 along Krupnik Fault: for the whole period of observation the trends are calculated as left lateral slip with 1.88 mm/a and a thrusting with 1.59 mm/a with high correlation coefficients. Co-seismic displacements from local and distant earthquakes were recorded. The significant impact was from M=7.4, 17 August, 1999, Izmit Earthquake, Turkey, showing a shortening of 8.34 mm, a right-lateral slip of 5.09 mm and a thrusting of 0.96 mm. After that, for a short period of time the regime of movement on fault was changed. Movements on the Struma system reveal lower rates. Both points show left-lateral movements, 0.28 mm/a at K5 and 0.09 mm/a at K12, and thrusting with 0.11 mm/a at K5 and 0.72 mm/a at K12., Nikolai Dobrev., and Obsahuje bibliografii
The present paper shows the results of 3D monitoring with the use of extensomet ers TM71 performed in Bulgaria in the framework of COST Action 625. This research was performed in selected areas: Simitli graben that is the most seismoactive area in Bulgaria; Madara plat eau - rock scarp with historical monument affe cted by rock toppling; East Rhodopes area - a possibly active fault zone and a large landslide. The most impressive results were established at Simitli graben area with the rate of 2.73 mm/year sinistral movement of Krupnik Fault. Local earthquakes located at NE part of the graben usually influence the movements along this fault. An acceleration of the left latera l movements during calm periods has been established, and respectively, the movements stop (or going in opposite direction) during seismic activity. At Madara site, the results from the 15 years monitoring show subsidence of rock s lices by 0.9 mm per year and si milar rate movement of the slices to South direction. Influence from Izmit earthquake, Vrancea earthquakes and local ones have been established. The monitoring of the fault at General Geshe vo Village, East Rhodopean area started in 2003. The first results show mainly gravitational movements - subsidence of NE block 1.5 mm/year., Nikolai Dobrev and Elka Avramova-Tacheva., and Obsahuje bibliografické odkazy
The paper presents the results of geodyn amic research in the fram e of the project COST 625 relating to active tectonic structures’ monitoring on the selected areas in Poland, Italy and Greece. Research was realised using a self-developed control and measurement system. The resu lts of researches for period 2000-2006 indi cate slight movements of observatio n points in the Sudety Mts. reaching several millimetres. However, the results confirm recent mobility of tectonic structures o f this area. Research realised in the Mediterranean Region objects - Gargano, Norcia (Italy) and Kaparelli (Greece) - indicate movements of observation points reaching over a dozen millimetres, particularly on the Gargano area. Continuation of cyclic control measurements on these objects is fully justified ., Stefan Cacoń, Bernard Kontny and Jarosław Bosy., and Obsahuje bibliografické odkazy