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29242. Silové působení laserových svazků na nesférické objekty
- Creator:
- Zemánek, Pavel, Jákl, Petr, and Brzobohatý, Oto
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- Kepler, Johannes, 1571-1630, fyzika, lasery, physics, lasers, 6, and 53
- Language:
- Czech and English
- Description:
- Silové působení světla na objekty je registrováno patrně od 17. století, kdy Johanes Kepler zmínil tento mechanismuus na základě pozorování odklonu chvostů komet od Slunce. Od této ukázky radiačního tlaku našly silové účinky světla řadu podob a aplikací ve všech přírodních vědách - od zachycení mikroorganismů ve fokusovaném laserovém svazku přes optická síta ke třídění částic, chlazení pohybu nanočástic až po stabilizaci orientace satelitu Kepler (jak zajímavá historická shoda). V předkládaném článku se zaměříme na chování nanočástic a mikročástic nekulového tvaru ozářených laserovými svazky různých vlastností., A force interaction between light and objects has been suggested since the 17th century when Johannes Kepler proposed this mechanism after observing comet tails which deviate from the Sun. Since this initial example of radiation pressure, the force interaction between light and objects has found many forms and applications in sciences - from trapping of microorganisms in a focused laser beam to optical sieves for particle sorting to cooling of nanoparticles motion or orientation stabilisation of the Kepler satellite (an interesting historical coincidence). In this contribution we will focus on the behaviour of nanoparticles and microparticles with a non-spherical shape illuminated by laser beams of various properties., Pavel Zemánek, Petr Jákl, Oto Brzobohatý., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29243. Silver and/or copper vermiculites and their antibacterial effect
- Creator:
- Hundáková, Marianna, Marta Valášková, Tomášek, Vladimír, Erich Pazdziora, and Matějová, Kateřina
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, vermikulit, stříbro, měď, vermiculite, silver, copper, structure characterization, antibacterial effect, 7, and 551
- Language:
- English
- Description:
- Vermiculite (V) from Brazil with aqueous solutions AgNO3 and/or Cu(NO3)2 was used for preparation of nanocomposites V/Ag, V/Cu, V/AgCu and V/CuAg using two procedures and their effect on bacteria was compared. Structural changes were evaluated using X-ray diffraction (XRD) analysis, Infrared spectroscopy (IRS) and Scanning electron microscopy (SEM). Elemental chemical composition was determined using X-ray fluorescence (XRF) analysis and the solutions were analyzed by Atomic emission spectroscopy with inductively coupled plasma (AES-ICP). Antibacterial properties of Ag- and Cu-vermiculites and combined Ag/Cu-vermiculites were tested on two bacteria groups: (1) Gram-positive, G+, (Staphylococcus aureus and Enterococcus faecalis) and (2) Gram-negative, G-, (Pseudomonas aeruginosa and Klebsiella pneumoniae). The samples under antibacterial testing showed different effective times and minimum inhibitory concentration (MIC) values. The Gram-negative bacteria showed higher sensitivity to the prepared samples than Gram-positive bacteria. The combined Cu/Ag vermiculites stopped the bacterial growth at lower MIC value., Marianna Hundáková, Marta Valášková, Vladimír Tomášek, Erich Pazdziora and Kateřina Matějová., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29244. Silvia Letavajová a kolektív, Súčasná alternatívna religiozita na Slovensku
- Creator:
- Holubová, Markéta
- Type:
- article, model:article, and TEXT
- Language:
- Czech
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29245. Silymarin as a potential hypocholesterolaemic drug
- Creator:
- Škottová, N. and Krečman, V.
- Type:
- article, model:article, and TEXT
- Subject:
- silymarin, silybin, liver lipids, plasma lipoproteins, and cholesterol
- Language:
- English
- Description:
- Silymarin, a mixture of flavonolignans from medicinal plant Silybum marianum, is used in supportive treatment of liver diseases of different etiology due to its hepatoprotective activity, which is considered to involve antioxidative and the membrane stabilizing effects. The liver plays an important role in regulation of metabolism of plasma lipoproteins, and liver injury is often reflected as a secondary dyslipoproteinaemia, which may lead to the development of atherosclerosis, particularly when associated with hypercholesterolaemia. This review summarizes the experimental evidence indicating that silymarin-induced protection of liver functions may be of benefit with regard to liver lipid metabolism related to the regulation of plasma lipoproteins. Moreover, some data suggest that silymarin could have a direct effect on liver cholesterol metabolism by inhibiting cholesterol biosynthesis. It is proposed that silymarin deserves to be studied as a potential hypocholesterolaemic agent.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29246. Silymarin component 2,3-dehydrosilybin attenuates cardiomyocyte damage following hypoxia/reoxygenation by limiting oxidative stress
- Creator:
- Gabrielová, E., Vladimír Křen, Martin Jabůrek, and Martin Modrianský
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, silymarin, dehydrosilybin, neonatal rat cardiomyocytes, postconditioning, reactive oxygen species, 14, and 612
- Language:
- English
- Description:
- Ischemic postconditioning and remote conditioning are potentially useful tools for protecting ischemic myocardium. This study tested the hypothesis that 2,3-dehydrosilybin (DHS), a flavonolignan component of Silybum marianum , could attenuate cardiomyocyte damage following hypoxia/ reoxygenation by decreasing the generation of reactive oxygen species (ROS). After 5-6 days of cell culture in normoxic conditions the rat neonatal cardiomyocytes were divided into four groups. Control group (9 h at normoxic conditions), hypoxia/ reoxygenation group (3 h at 1 % O2 , 94 % N2 and 5 % CO2 followed by 10 min of 10 μmol·l -1 DHS and 6 h of reoxygenation in normoxia) and postconditioning group (3 h of hypoxia, three cycles of 5 min reoxygenation and 5 min hypoxia followed by 6 h of normoxia). Cell viability assess ed by propidium iodide staining was decreased after DHS treatment consistent with increased levels of lactatedehydrogenase (LDH) after reoxygenation. LDH leakage was significantly reduced when cardiomyocytes in the H/Re group were exposed to DHS. DHS treatment reduced H2O2 production and also decreased the generation of ROS in the H/Re group as evidenced by a fluorescence indicator. DHS treatment reduces reoxygenation-induced injury in cardiomyocytes by attenuation of ROS generation, H2O2 and protein carbonyls levels. In addition, we found that both the postconditioning protocol and the DHS treatment are associated with restored ratio of phosphorylated/total protein kinase C epsilon, relative to the H/Re group. In conclusion, our data support the protective role of DH S in hypoxia/reperfusion injury and indicate that DHS may act as a postconditioning mimic., E. Gabrielová, V. Křen, M. Jabůrek, M. Modrianský., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29247. Šíma v Bibliothéque Nationale
- Creator:
- Šmejkal, František
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Czech
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29248. Similar effects of lamotrigine and phenytoin against cortical epileptic foci in immature rats
- Creator:
- Klára Bernášková and Pavel Mareš
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, mozková kůra, cerebral cortex, epileptic focus, bicuculline methiodide, immature rat, antiepileptic drugs, 14, and 612
- Language:
- English
- Description:
- Action of antiepileptic drugs in immature brain may differ from that in adult brain. The aim of our study was to study an anticonvulsant action of lamotrigine and phenytoin, i.e. two drugs active against partial seizures in adult experimental animals as well as human patients, in a model of simple partial seizures in immature rats. Epileptic foci were induced by local application of bicuculline methiodide on sensorimotor cortical area of 12-dayold rat pups. The animals were pretreated with lamotrigine (LTG, 10 or 20 mg/kg i.p.) or phenytoin (PHT, 15, 30 or 60 mg/kg i.p.). Control rats for LTG received saline, controls for PHT solvent composed of propyleneglycol, ethanol and water. Influence of either drug on interictal activity was negligible. High doses of both LTG and PHT suppressed the transition into ictal phases and shortened the duration of persisting seizures. The tricomponent solvent exhibited moderate activity against ictal activity if compared with saline controls. The two drugs exhibited similar action in our model, i.e. the suppression of secondary generalization from epileptic focus. This action is comparable to that described for human patients and adult experimental animals. In favor of lamotrigine speaks the absence of serious side effects., K. Bernášková, P. Mareš., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29249. Similar effects of ozone on four cultivars of lettuce in open top chambers during winter
- Creator:
- Calatayud, A., Alvarado, J. W., and Barreno, E.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, Lactuca sativa, lipid peroxidation, malondialdehyde, and root length
- Language:
- Multiple languages
- Description:
- Ozone is the major phytotoxic air pollutant that reduces the yield of several agricultural crops in the Spanish Mediterranean area. We studied four lettuce cultivars (Lactuca sativa L.) for the effects of different O3 concentrations during the winter on chlorophyll (Chl) a fluorescence, lipid peroxidation, and root length in outdoor open-top chambers. Under O3 the photosynthetic quantum conversion declined while heat emissions increased in all cultivars; these results provide more evidence of non-filtered air with additional ozone (NFA+O3) treatment compared with non-filtered air (NFA) and charcoal filtered ozone-free air (CFA). Changes in the Chl a fluorescence may be associated with an increase in membrane lipid peroxidation as well as with observed reduction of root length under O3 stress. and A. Calatayud, J. W. Alvarado, E. Barreno.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29250. Similar susceptibility to excess irradiance in sun and shade acclimated saplings of Norway spruce [Picea abies (L.) Karst.] and stone pine (Pinus cembra L.)
- Creator:
- Gamper, R., Mayr, S., and Bauer, H.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, frost hardening, low temperature, and net photosynthetic rate
- Language:
- Multiple languages
- Description:
- We compared the responses of sun and shade acclimated saplings of Picea abies and Pinus cembra to excess photosynthetic photon flux density (PPFD) equivalently exceeding the level for saturating net photosynthetic rate (PN). Exposure for 2 h up to 2000 µmol(photon) m-2 s-1 did not affect radiant energy saturated PN. Photoinhibition of photosynthesis was indicated by a small (10 %) reduction of the potential efficiency of photosystem 2 as derived from measurements of chlorophyll fluorescence (FV/FM). However, the extent of FV/FM reduction and half-time for recovery were similar in sun and shade acclimated saplings of both species. Furthermore, the effect on FV/FM was not stronger when the plants were exposed to excess PPFD at 5 °C instead of 15 °C. Frost-hardening of plants increased slightly their resistance to excess PPFD. Establishment of these conifer saplings usually acclimated to shade in their natural habitat may hardly be endangered by a sudden increase of PPFD, e.g., by gap formation. and R. Gamper, S. Mayr, H. Bauer.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public