Left ventricular assist devices (LVAD), currently used in treatment of terminal heart failure, are working on principle of rotary pump, which generates continuous blood flow. Non-pulsatile flow is supposed to expose endothelial cells to high stress and potential damage. Therefore, we investigated longitudinal changes in concentration of circulating endothelial microparticles (EMP) as a possible marker of endothelial damage before and after implantation of LVAD. Study population comprised 30 patients with end-stage heart failure indicated for implantation of the Heart Mate II LVAD. Concentrations of microparticles were measured as nanomoles per liter relative to phosphatidylserine before and 3 months after implantation. At 3 months after implantation we observed significant decrease in concentration of EMP [5.89 (95 % CI 4.31-8.03) vs. 3.69 (95 % CI 2.70-5.03), p=0.03] in the whole group; there was no difference observed between patients with ischemic etiology of heart failure (n=18) and with heart failure of non-ischemic etiology (n=12). In addition, heart failure etiology had no effect on the rate of EMP concentration decrease with time. These results indicate possibility that LVAD do not cause vascular damage 3 months after implantation. Whether these results suggest improvement of vascular wall function and of endothelium is to be proved in long-term studies., P. Ivak, J. Pitha, P. Wohlfahrt, I. Kralova Lesna, P. Stavek, Z. dorazilova, J. Stepankova, J. Maly, M. Pokorny, I. Netuka., and Obsahuje bibliografii
Článek se zabývá chronologií eneolitických inhumací z prostoru Moravy na základě radiokarbonového datování. Datováno bylo celkem 17 jedinců pomocí 20 radiokarbonových dat, přičemž se jedná především o jedince bez hrobové výbavy, či jedince pocházející z problematických kontextů. Studie pokrývá zejména období starého eneolitu, méně pak střední a pozdní eneolit. K většině pojednávaných pohřbů jsou nově publikovány nálezové okolnosti a antropologické posudky. Na základě chronologické analýzy hrobů datovaných radiokarbonovým datováním lze přibližně definovat časový rozptyl jednotlivých způsobů pohřbívání na Moravě. Nejspolehlivěji lze datovat ploché hroby s jedinci v natažené poloze bez hrobových přídavků do ca 3800–3600 BC. and The article addresses the chronology of Eneolithic inhumation burials in Moravia based on radiocarbon dating. A total of 17 individuals were dated using 20 radiocarbon dates, primarily individuals without grave goods or individuals from problematic contexts. The study mainly covers the period of the Early Eneolithic, to a lesser extent the Middle and Late Eneolithic. The find contexts and anthropological assessments are newly published for most of the burials in question. Based on the chronological analysis of graves dated by radiocarbon dating, it is possible to approximately define the time dispersion of individual burial methods in Moravia. Flat graves with individuals in a stretched position without grave goods can be most reliably dated to about 3800–3600 BC.
Využitie kombinovaného systému na báze pyrolýzy biomasy, resp. triedeného komunálneho odpadu, v kombinácii s čistením exhalátov za pomoci elektrického výboja, poskytuje zaujímavú možnosť znižovania skleníkotvorného CO2 a súčasne rozvoja niektorých foriem obnoviteľných zdrojov energie. Testovaný pilotný systém z hľadiska veľkosti zodpovedá približne potrebám bežne stavaných rodinných domov., Marcela Morvová., and Obsahuje bibliografii
Energetická soběstačnost patří podle Světové obchodní organizace mezi desítku výzev, jimž budeme čelit v následujících desetiletích. Současné dominantní zdroje energie nejsou trvalým řešením, a tak musíme nejen hledat zdroje nové, ale přitom i zdokonalovat její přeměnu a vyřešit skladování. Právě to je jedním z úkolů Strategie AV21. and Luděk Svoboda.
The effect of drought stress on energy dissipation and antioxidant enzyme system in two sweet sorghum inbred lines (M-81E and Roma) was investigated. Results showed that the germination indicator increased more in M-81E than that in Roma under rehydration. Under drought stress, both the maximal photochemical efficiency of PSII (Fv/Fm) and oxidoreductive activity (ΔI/I0) of Roma decreased more than those in M-81E. Relative to Fv/Fm, the ΔI/I0 decreased markedly, which indicated that PSI was more sensitive to drought stress than PSII. Increases in the reduction state of QA (1-qp), nonphotochemical quenching (NPQ) and minimal fluorescence yield of the dark-adapted state (F0) were greater in Roma than those in M-81E; meanwhile, the H2O2 content was lower in M-81E than that in Roma. Our results suggested that the photoinhibition might be related to the accumulation of reactive oxygen species (ROS). The antioxidant enzyme system and energy dissipation of M-81E could respectively increase drought tolerance by eliminating ROS and excess energy more efficiently than that of Roma., Y. Y. Guo, S. S. Tian, S. S. Liu, W. Q. Wang, N. Sui., and Obsahuje bibliografii
Energy transfer of aromatic amino acids in photosystem 2 (PS2) core antenna complexes CP43 and CP47 was studied using absorption spectroscopy, fluorescence spectroscopy, and the 0.35 nm crystal structure of PS2 core complex. The energy of tyrosines (Tyrs) was not effectively transferred to tryptophans (Trps) in CP43 and CP47. The fluorescence emission spectrum of CP43 and CP47 by excitation at 280 nm should be a superposition of the Tyr and Trp fluorescence emission spectra. The aromatic amino acids in CP43 and CP47 could transfer their energy to chlorophyll (Chl) a molecules by the Dexter mechanism and the Föster mechanism, and the energy transfer efficiency in CP47 was much higher than that in CP43. In CP47 the Föster mechanism must be the dominant energy transfer mechanism between aromatic amino acids and Chl a molecules, whereas in CP43 the Dexter mechanism must be the dominant one. Hence solar ultraviolet radiation brings not only damages but also benefits to plants. and Y. G. Qu .... [et al.].
We examined photosynthetic activities and thermostability of photosystem 2 (PS2) in leaves of elm (Ulmus pumila) seedlings from initiation to full expansion. During leaf development, net photosynthetic rate (PN) increased gradually and reached the maximum when leaves were fully developed. In parallel with the increase of PN, chlorophyll (Chl) content was significantly elevated. Chl a fluorescence measurements showed that the maximum quantum yield of PS2 (ϕPS2), the efficiency a trapped exciton, moved an electron into the electron transport chain further than QA- (Ψo), and the quantum yield of electron transport beyond QA (ϕEo) increased gradually. These results were independently confirmed by our low irradiance experiments. When subjected to progressive heat stress, the young leaves exhibited considerably lower ϕPS2 and higher minimal fluorescence (F0) than the mature leaves, revealing the highly sensitive nature of PS2 under heat in the newly initiating leaves. Further analysis showed that PS2 structure in the newly initiating leaves was strongly altered under heat, as evidenced by the increased fluorescence signals at the position of the K step. We therefore demonstrated an inhibition in the oxygen-evolving complex (OEC) in the young leaves. This resulted in decrease in amount of the functional PS2 reaction centres and relative increase in the PS2 reaction centres with inhibited electron transport at the acceptor side under heat. We suggest that the enhanced thermostability of PS2 during leaf development is associated with improved OEC stability. and C.-D. Jiang ... [et al.].
Pigment contents of chloroplasts and net photosynthetic rate were dramatically reduced in maize leaves suffering from iron deficiency. However, the reduction in photosynthesis was probably not caused by decreased contents of chlorophylls and carotenoids and by photon absorption; the primary limiting factor for photosynthesis may rather be the decrease of electron transport activity in photosystem 1. Iron-deficient leaves suffered serious acceptor-side photoinhibition, and more than 60 % of absorbed photons were dissipated, while less than 40 % was used in photochemical reaction. Thermal energy dissipation depending on xanthophyll cycle and D1 protein turnover was enhanced when acceptor-side photoinhibition occurred in iron-deficient maize leaves. and Chuang-Dao Jiang, Hui-Yuan Gao, Qi Zou.