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8782. Mechanical behavior of polysiloxane matrix: based composite reinforced with basalt fibres at elevated temperatures
- Creator:
- Černý, Martin, Sucharda, Zbyněk, and Petr Glogar
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, kompozitní materiály, mechanické vlastnosti materiálů, composite materials, mechanical properties of materials, basalt fibres, 7, and 551
- Language:
- English
- Description:
- Martin Černý, Zbyněk Sucharda and Petr Glogar. and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8783. Mechanical properties of mitral allografts are not reasonably influenced by cryopreservation in sheep model
- Creator:
- Jaroslav Hlubocký, Aleš Mokráček, Nováček, V., Jan Vojáček, Jan Burkert, Petra Kochová, Klepáček, J., Pepper, J., and Jaroslav Špatenka
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, mitrální chlopeň, mitral valve, mitral allograft, cryopreservation, maxwell model, viscoelastic properties, 14, and 612
- Language:
- English
- Description:
- A mitral allograft is us ed exceptionally in the mitral, as well as in the tricuspid position, mostly as an experimental surgical procedure. The authors decided to evaluate the possibility of inserting a cryopreserved mitral allograft into the tricuspid position in a sheep experimental model. Within the framework of this experimental project the mechanical properties of the cryopreserved mitral allograft were tested. A novel methodology studying the functional unit composed of mitral annulus, leaflet, chordae tendinaea, and papillary muscle is presented. A five-parameter Maxwell model was applied to characterize the viscoelastic behavior of sheep mitral valves. A control group of 39 fresh mitral specimens and a test group of 13 cryopreserved mitral allografts from tissue bank were tested. The testing protocol consisted of six loading cycles with 1 mm elongation every 5 min. There was no significant difference in the mean values of the determined parameters (p> 0.05) which confirms the main hypothesis that cryopreservation does not influence significantly material parameters characterizing the tissue mechanics. Slight discrepancy is observed in variances of viscous parameters suggesting that the values of the test group may be spread over larger interval due to the treatment., J. Hlubocký ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8784. Mechanical response of porous scaffolds for cartilage engineering
- Creator:
- Josef Jančář, Slovíková, A., Evžen Amler, Petr Krupa, Helga Kecová, Ladislav Plánka, Petr Gál, and Alois Nečas
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, nanovlákna, kyselina hyaluronová, mezenchymální kmenové buňky, nanofibers, hyaluronic acid, mesenchymal stem cells, chitosan, hydroxyapatite, joint resurfacing, 14, and 612
- Language:
- English
- Description:
- a1_Mechanical properties of scaffolds seeded with mesenchymal stem cells used for cartilage repair seem to be one of the critical factors in possible joint resurfacing. In this paper, the effect of adding hyaluronic acid, hydroxyapatite nanoparticles or chitosan nanofibers into the cross-linked collagen I on the mechanical response of the lyophilized porous scaffold has been investigated in the dry state at 37 oC under tensile loading. Statistical significance of the results was evaluated using ANOVA analysis. The results showed that the addition of hyaluronic acid significantly (p<<0.05) reduced the tensile elastic modulus and enhanced the strength and deformation to failure of the modified cross-linked collagen I under the used test conditions. On the other hand, addition of hydroxyapatite nanoparticles and chitosan nanofibers, respectively, increased the elastic modulus of the modified collagen ten-fold and four-fold, respectively. Hydroxyapatite caused significant reduction in the ultimate deformation at break while chitosan nanofibers enhanced the ultimate deformation under tensile loading substantially (p<<0.05). The ultimate tensile deformation was significantly (p<<0.05) increased by addition of the chitosan nanofibers. The enhanced elastic modulus of the scaffold was translated into enhanced resistance of the porous scaffolds against mechanical load compared to scaffolds based on cross-linked neat collagen or collagen with hyaluronic acid with similar porosity. It can be concluded that enhancing the rigidity of the compact scaffold material by adding rigid chitosan nanofibers can improve the resistance of the porous scaffolds against compressive loading, which can provide more structural protection to the seeded mesenchymal stem cells when the construct is implanted into a lesion., a2_Moreover, scaffolds with chitosan nanofibers seemed to enhance cell growth compared to the neat collagen I when tested in vitro as well as the scaffold stability, extending its resorption to more than 10 weeks., J. Jančář, A. Slovíková, E. Amler, P. Krupa, H. Kecová, L. Plánka, P. Gál, A. Nečas., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8785. Mechanism of Na+ Deprivation-Induced Catecholamine Secretion From Freshly Isolated Bovine Adrenal Chromaffin Cells
- Creator:
- Isosaki, M. and Nakashima, T.
- Format:
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- Type:
- article, studie, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Na+-Ca2+ exchange, Na+ deprivation, Catecholamine secretion, Adrenal medulla · Chromaffin, 14, and 612
- Language:
- English
- Description:
- We have studied the mechanism of Na+ deprivation-induced catecholamine secretion from freshly isolated bovine adrenal chromaffin cells. Na+ deprivation-induced catecholamine secretion depended on free extracellular Ca2+ concentrations and was almost parallel to 45Ca2+ influx into the cells under various experimental conditions. Furthermore, Na+ deprivation-induced 45Ca2+ influx and catecholamine secretion were actually induced by a relative Na+ concentration gradient across the plasma membrane, but not by simple omission of Na+ from the medium. These results indicate that the deprivation of Na+ from the medium changes the relative Na+ gradient across the plasma membrane and results in Ca2+ influx via a reverse mode of Na+-Ca2+ exchange rather than by inducing Ca2+ entry through Ca2+ channels by eliminating the competition between extracellular Na+ and Ca2+., M. Isosaki, T. Nakashima., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8786. Mechanism of rigid overlaying of carboniferous strata failure in face mining in the case of a multiseams deposit
- Creator:
- Eva Jiránková, Staš, Lubomír, Vlastimil Kajzar, and Doležalová, Hana
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, tensor stress measurement, longwall mining, subsidence trough, rock mass, overlying strata, 7, and 551
- Language:
- English
- Description:
- The technique of assessing the failure of rigid overlying strata is applicable to deep mining with thick coal seams (a thickness of more than 1 m in the Ostrava-Karvina Coalfield), and in one case to longwall mining with controlled caving. The assessment of failure of rigid overlying strata makes it possible to distinguish whether the rigid overlying strata of rocks has been deformed or whether a strutting arch has been formed over the goaf below which is an area that is free from stress. Good knowledge of the mining, technical and geological conditions of a given site is a prerequisite for successful evaluation. There are advantages to utilising surface measurements for interpreting the effects of changes in rock mass, especially in areas of high overlying strata. The practical importance of failure assessment of overlying strata consists in determining the size of the mined-out area where the deformation of the rigid overlying strata occurred, which is dependent on the character of the rock mass. This paper is set in the context of the expected width of the goaf during deformation of rigid overlying strata within parameters that describe the mining and geological conditions of the locality. Changes in the area of the goaf, based the results of tensometric measurements, will also be placed in context., Eva Jiránková, Lubomír Staš, Vlastimil Kajzar and Hana Doležalová., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8787. Mechanisms of neurogenic pulmonary edema development
- Creator:
- Jiří Šedý, Josef Zicha, Jaroslav Kuneš, Pavla Jendelová, and Eva Syková
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, experimentální medicína, edém, potkan, plíce, poranění míchy, experimental medicine, edema, Rattus norvegicus, lungs, spinal cord injuries, neurogenic pulmonary edema, model, 14, and 612
- Language:
- English
- Description:
- Neurogenic pulmonary edema is a life-threatening complication, known for almost 100 years, but its etiopathogenesis is still not completely understood. This review summarizes current knowledge about the etiology and pathophysiology of neurogenic pulmonary edema. The roles of systemic sympathetic discharge, central nervous system trigger zones, intracranial pressure, inflammation and anesthesia in the etiopathogenesis of neurogenic pulmonary edema are considered in detail. The management of the patient and experimental models of neurogenic pulmonary edema are also discussed., J. Šedý, J. Zicha, J. Kuneš, P. Jendelová, E. Syková., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8788. Mechanisms of the 14-3-3 protein function: regulation of protein function through conformational modulation
- Creator:
- Obsilova, V., Marie Kopecká, Kosek, D., Kacirova, M., Kylarova, S., Rezabkova, L., and Obsil, T.
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, bílkoviny, proteins, 14-3-3 protein, regulator of G-protein signalling (RGS3), phosducin, neutral trehalase, Bmh1, conformation, signaling, 14, and 612
- Language:
- English
- Description:
- Many aspects of protein function regulation require specific protein-protein interactions to carry out the exact biochemical and cellular functions. The highly conserved members of the 14-3-3 protein family mediate such interactions and through binding to hundreds of other proteins provide multitude of regulatory functions, thus playing key roles in many cellular processes. The 14-3-3 protein binding can affect the function of the target protein in many ways including the modulation of its enzyme activity, its subcellular localization, its structure and stability, or its molecular interactions. In this minireview, we focus on mechanisms of the 14-3- 3 protein-dependent regulation of three important 14-3-3 binding partners: yeast neutral trehalase Nth1, regulator of G-protein signaling 3 (RGS3), and phosducin., V. Obsilova ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8789. Mechanismus BEH a jeho skalární boson: Přednáška u příležitosti udělení Nobelovy ceny za fyziku za rok 2013
- Creator:
- Englert, François and Gregora, Ivan
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fyzika, Nobelova cena, physics, Nobel Prize, 6, and 53
- Language:
- Czech
- Description:
- The 2013 Nobel Prize for Physics was shared by François Englert and Peter Higgs. The presented articles show the text of the address given in during the award ceremony., François Englert ; přeložil Ivan Gregora., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8790. Mechanismus vášní v "économie animale": k otázce vášní duše v osvícenské medicíně
- Creator:
- Tinková, Daniela
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- láska, melancholie, osvícenství, fyziologie, psychiatrie, love, melancholy, enlightenment, physiology, psychiatry, vášně duše, passions of soul, 8, and 94(437)
- Language:
- Czech and English
- Description:
- The aim of this study is to show how the emotions - in particular the so-called "passions of the soul" - were understood and interpreted in the medical thinking of the late Enlightenment. We focus chiefly on three innovations in 18th century medicine: the "discovery" of the neuro-cerebral system (the ’birth’ of neurology); the search for the "seat" of illnesses in particular organs (the "birth" of pathological anatomy); and the gradual separation of the body and the soul as objects of medical enquiry (the "birth of psychiatry). We consider whether, and to what extent, these innovations contributed to the breakdown of the "old" diagnostic paradigms of the "passions of the soul", or whether in fact they helped to maintain them. We also discuss to what extent the consideration of these passions fostered a new approach to the relationship between the body and the soul in Enlightenment medicine. Some of the phenomena studied are illustrated by specific examples of (erotic) love and melancholy. and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public