Impaired cerebrovascular reactivity (CVR), an important risk factor for future stroke, is affected by a presence carotid stenosis. However, in some cases CVR can be impaired in the absence of carotid stenosis due to several poorly characterized mechanisms. We hypothesized that arterial stiffening as observed in coronary heart disease (CHD) could be associated with alteration in CVR in CHD patients without carotid stenosis. The study population consisted of patients referred for coronary angiography without significant carotid stenosis (<50 %). CVR was evaluated by breath holding index (BHI) measured with transcranial color code duplex ultrasound. Arterial stiffness was assessed by pulse wave velocity (PWV) measured by the oscillometric method. The extent of coronary atherosclerosis was quantified by Gensini score (GS). Out of 186 subjects, sixty-two patients fulfilled the inclusion and exclusion criteria. BHI decreased with increasing PWV (r = -0.47, p<0.001). Decrease in BHI was significantly inversely associated with GS (r = -0.61, p<0.001). GS was associated with PWV (p<0.001). In conclusion, impaired CVR was associated with increased arterial stiffening in CHD patients in the absence of significant carotid stenosis. Thus, we speculate that increased arterial stiffness may at least partially contribute to the pathophysiology of CVR alteration in coronary artery disease., D. Rucka, J. Marek, Z. Rucklova, J.-C. Lubanda, S. Havranek, J. Skvaril, P. Varejka, M. Chochola, D. Karetova, J. Korinek, A. Linhart., and Obsahuje bibliografii
Low temperature has a negative impact on plant cells and results in the generation of reactive oxygen species (ROS). In order to study the role of ascorbate under chilling stress, the response of an ascorbate-deficient Arabidopsis thaliana mutant vtc2-1 to low temperature (2°C) was investigated. After chilling stress, vtc2-1 mutants exhibited oxidative damage. An increase in the H2O2 generation and the production of thiobarbituric acid reactive substances (TBARS), and a decrease in chlorophyll content, the maximal photochemical efficiency of PSII (Fv/Fm) and oxidizable P700 were also noted. The ratio of ascorbate/dehydroascorbate and reduced glutathione/oxidzed glutathione in the vtc2-1 mutants were reduced, compared with the wild type (WT) plants. The activities of antioxidant enzymes, such as catalase (CAT) and ascorbate peroxidase (APX), and soluble antioxidants were lower in the vtc2-1 mutants than those in WT plants. These results suggested that the ascorbate-deficient mutant vtc2-1 was more sensitive to chilling treatment than WT plants. The low temperature-induced oxidative stress was the major cause of the decrease of PSII and PSI function in the vtc2-1 mutants. Ascorbate plays a critical role of defense without which the rest of the ROS defense network is unable to react effectively., L. Y. Wang ... [et al.]., and Obsahuje bibliografii
The theory of third-order aberrations of the system rotary symmetrical aspheric thin lenses and the relations for calculation of the shape rotary symmetrical aspheric spectacle lenses with zero astigmatism are stated. A comparison the possibility of the aspheric and spherical spectacle lenses is presented. and Je uvedena teorie aberací 3. řádu soustavy tenkých rotačně symetrických asférických čoček. Jsou odvozeny vztahy pro výpočet tvaru rotačně symetrické asférické brýlové čočky s korigovaným astigmatismem a je provedeno srovnání se sférickou brýlovou čočkou.
Samples of bottom ash and fly ash coming from the combustion of lignite with the addition of limestone, from the cocombustion of lignite and wood residue with limestone and from co-combustion of lignite, wood residue, biological sludges from the waste water treatment plant and municipal waste as well with the addition of limestone were examined. Scanning electron microscopy with X-ray microanalyser were used for study of morphology and chemical composition of ash particles. The results were compared with average composition of bottom ashes, fly ashes and input materials found by X-ray fluorescence spectrometry and with phase composition found by X-ray diffraction method. There were proved no significant differences in the character and the structure of individual samples coming from various regimes of combustion., Vladimír Tomášek, Ondřej Šustai, Jana Seidlerová, Zdeněk Klika, Martin Stach, Zdeněk Weiss and Václav Roubíček., and Obsahuje bibliografii
Osteosarcoma (OS), a severe malignant bone tumour, usually occurs in adolescents and children and has a poor prognosis. Asiatic acid (AA), an active component isolated from Centella asiatica (L.) Urb., exhibits appreciable anti-oxidant and anti-tumour activities. So far, the effects and underlying mechanisms of AA against OS have not been clarified. Here, we explored the anti-tumour effects of AA against human OS and the involved mechanism mediating its actions. To evaluate effects of AA on the cell proliferation of human OS cells, cell viability and colony formation assays were performed. Flow cytometry was used to evaluate apoptosis in OS cells exposed to AA and mitochondrial membrane potential. Western blotting and RT-PCR were applied to determine expression of the relevant proteins and their mRNA levels. Our explorations showed that AA inhibits proliferation of human OS cells in a concentration- and time-dependent manner, and induces apoptosis of OS cells by the intrinsic (mitochondrial) pathway. Importantly, we found that inhibition of the AA-induced phosphorylation of JAK2/STAT3 signalling molecules and the decrease in MCL-1 contributed to the anti-tumour efficacy of AA. Collectively, our results suggest that AA could evoke mitochondrial- induced apoptosis in human OS cells by suppression of the JAK2/STAT3 pathway and MCL-1 expression. These results strongly demonstrate that AA could be a potential anti-tumour agent for OS treatment.
Tento článek přibližuje čtenáři svět prvních portugalských mořeplavců a jejich setkání s exotickou faunou Asie v 16. století. Důraz klade především na nosorožce a slona, ale neopomíjí ani další živočichy a věnuje se i původu některých drahocenných orientálních látek živočišného původu, pro Evropany dlouho neznámému. Text bohatě využívá citací z pramenů., This article presents the world of the first Portuguese navigators and their encounters with exotic Asian fauna in the 16th century. It primarily highlights the rhinoceros and elephants, but does not omit other animals. It also focuses on the sources of some valuable oriental substances of animal origin, which was unknown to Europeans for a long time., and Karel Staněk.
Mezinárodní fyzikální soutěže mají již tradici po několik desítek let a účastní se jich soutěžící z mnoha zemí světa. Kromě toho postupně vznikly i tzv. zonální fyzikální soutěže, mezi něž patří např. Iberolatinskoamerická fyzikální soutěž a Asijská fyzikální olympiáda, určená pro soutěžící z Asie a Oceánie., Ivo Volf, Jan Kříž., and Obsahuje seznam literatury
An Adhesive bonded surface mechanical treatment is one of necessary steps in an adhesive bonding technology application. A grit blasting ranges among prospective adhesive bonded surface treatment technologies. A resulted surface structure depends on many factors. A grit blasting material grain size together with specific fraction size belongs to basic parameters. this paper deals with an influence of the grain on surface roughness parameters as well as on a charge of a adhesive bond strength. and Mechanická úprava lepeného povrchu je jedním z nezbytných kroků při aplikaci technologie lepení. Mezi perspektivní technologie úpravy lepeného povrchu patří tryskání. Výsledná textura povrchu je závislá na mnoha parametrech. Mezi základní parametry patří zrnitost tryskaného materiálu a s tím související měrný rozměr zrna. Článek pojednává o vlivu rozměru zrna na parametry drsnosti povrchu a rovněž i jejich vliv na změnu pevnosti lepeného spoje.