221 research outputs found

    Four Is Better Than 1—Strength in Numbers!

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    High Glucose-enhanced Acetylcholine Stimulated CGMP Masks Impaired Vascular Reactivity in Tail Arteries from Short-Term Hyperglycemic Rats

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    Impaired vascular endothelium-dependent relaxation and augmented contractile responses have been reported in several models of long-term hyperglycemia. However, the effects of short-term ambient hyperglycemia are poorly understood. Since oxidative stress has been implicated as a contributor to impaired vascular function, we investigated the following

    Structural Diversity of the Active N-Terminal Kinase Domain of p90 Ribosomal S6 Kinase 2

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    The p90 ribosomal protein kinase 2 (RSK2) is a highly expressed Ser/Thr kinase activated by growth factors and is involved in cancer cell proliferation and tumor promoter-induced cell transformation. RSK2 possesses two non-identical kinase domains, and the structure of its N-terminal domain (NTD), which is responsible for phosphorylation of a variety of substrates, is unknown. The crystal structure of the NTD RSK2 was determined at 1.8 Å resolution in complex with AMP-PNP. The N-terminal kinase domain adopted a unique active conformation showing a significant structural diversity of the kinase domain compared to other kinases. The NTD RSK2 possesses a three-stranded βB-sheet inserted in the N-terminal lobe, resulting in displacement of the αC-helix and disruption of the Lys-Glu interaction, classifying the kinase conformation as inactive. The purified protein was phosphorylated at Ser227 in the T-activation loop and exhibited in vitro kinase activity. A key characteristic is the appearance of a new contact between Lys216 (βB-sheet) and the β-phosphate of AMP-PNP. Mutation of this lysine to alanine impaired both NTDs in vitro and full length RSK2 ex vivo activity, emphasizing the importance of this interaction. Even though the N-terminal lobe undergoes structural re-arrangement, it possesses an intact hydrophobic groove formed between the αC-helix, the β4-strand, and the βB-sheet junction, which is occupied by the N-terminal tail. The presence of a unique βB-sheet insert in the N-lobe suggests a different type of activation mechanism for RSK2

    A Wide Field Survey of Satellite Galaxies around the Spiral Galaxy M106

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    We present a wide field survey of satellite galaxies in M106 (NGC 4258) covering a 1.7\degr \times 2\degr field around M106 using Canada-France-Hawaii Telescope/MegaCam. We find 16 satellite galaxy candidates of M106. Eight of these galaxies are found to be dwarf galaxies that are much smaller and fainter than the remaining galaxies. Four of these galaxies are new findings. Surface brightness profiles of 15 out of 16 satellite galaxies can be represented well by an exponential disk profile with varying scale length. We derive the surface number density distribution of these satellite galaxies. The central number density profile (d <100<100 kpc) is well fitted by a power-law with a power index of 2.1±0.5-2.1\pm0.5, similar to the expected power index of isothermal distribution. The luminosity function of these satellites is represented well by the Schechter function with a faint end slope of 1.190.06+0.03-1.19^{+0.03}_{-0.06}. Integrated photometric properties (total luminosity, total colour, and disk scale length) and the spatial distribution of these satellite galaxies are found to be roughly similar to those of the Milky Way and M31.Comment: Accepted by MNRA

    Design of Mixing Station for Alternative Gaseous Fuels

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    Úkolem diplomové práce je navrhnout potrubní rozvod plynů do směšovací stanice a následně i navrhnout samotnou směšovací stanici. V textové části je nejprve vytvořena rešerše týkající se využívání technických a topných plynů v praxi. Na tuto část postupně navazují specifikace plynů, které se budou dopravovat do směšovací stanice. Ve výpočtové části se práce prostřednictvím výpočtových vztahů zabývá složením směsného plynu, fyzikálními vlastnostmi jednotlivých plynů i samotného plynu směsného, přičemž jsou vypočteny a navrženy potrubní tratě jednotlivých plynů směřujících do směšovací stanice. Konstrukční část práce se zabývá návrhem směšovací stanice a směšovací komory, ve které se jednotlivé plyny mísí. Grafická část práce obsahuje schémata jednotlivých potrubních tratí a směšovací stanice, 3D model směšovací komory a výkres směšovací komory.The task of the diploma thesis is to design the pipeline distribution of gases to the mixing station and then design the mixing station itself. In the text part is first created a search regarding the use of technical and heating gases in practice. This part is followed by the gas specifications that will be transported to the mixing station. In the computational part, the work with the help of calculation relations deals with the composition of the mixed gas, the physical properties of the individual gases and the mixing gas itself, and the pipelines of the individual gases leading to the mixing station are calculated and designed. The construction part deals with the design of the mixing station and the mixing chamber, in which the individual gases are mixed. The graphical part of the thesis contains diagrams of individual pipeline lines and mixing stations, a 3D model of the mixing chamber and a drawing of the mixing chamber.361 - Katedra energetikyvýborn

    Outcomes of patients with acute respiratory failure on veno-venous extracorporeal membrane oxygenation requiring additional circulatory support by veno-venoarterial extracorporeal membrane oxygenation

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    ObjectiveVeno-venous (V-V) extracorporeal membrane oxygenation (ECMO) is increasingly used to support patients with severe acute respiratory distress syndrome (ARDS). In case of additional cardio-circulatory failure, some experienced centers upgrade the V-V ECMO with an additional arterial return cannula (termed V-VA ECMO). Here we analyzed short- and long-term outcome together with potential predictors of mortality.DesignMulticenter, retrospective analysis between January 2008 and September 2021.SettingThree tertiary care ECMO centers in Germany (Hannover, Bonn) and Switzerland (Zurich).PatientsSeventy-three V-V ECMO patients with ARDS and additional acute cardio-circulatory deterioration required an upgrade to V-VA ECMO were included in this study.Measurements and main resultsFifty-three patients required an upgrade from V-V to V-VA and 20 patients were directly triple cannulated. Median (Interquartile Range) age was 49 (28–57) years and SOFA score was 14 (12–17) at V-VA ECMO upgrade. Vasoactive-inotropic score decreased from 53 (12–123) at V-VA ECMO upgrade to 9 (3–37) after 24 h of V-VA ECMO support. Weaning from V-VA and V-V ECMO was successful in 47 (64%) and 40 (55%) patients, respectively. Duration of ECMO support was 12 (6–22) days and ICU length of stay was 32 (16–46) days. Overall ICU mortality was 48% and hospital mortality 51%. Two additional patients died after hospital discharge while the remaining patients survived up to two years (with six patients being lost to follow-up). The vast majority of patients was free from higher degree persistent organ dysfunction at follow-up. A SOFA score &gt; 14 and higher lactate concentrations at the day of V-VA upgrade were independent predictors of mortality in the multivariate regression analysis.ConclusionIn this analysis, the use of V-VA ECMO in patients with ARDS and concomitant cardiocirculatory failure was associated with a hospital survival of about 50%, and most of these patients survived up to 2 years. A SOFA score &gt; 14 and elevated lactate levels at the day of V-VA upgrade predict unfavorable outcome

    Satellite abundances around bright isolated galaxies

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    We study satellite galaxy abundances in SDSS by counting photometric galaxies around isolated bright primaries. We present results as a function of the luminosity, stellar mass and colour of the satellites, and of the stellar mass and colour of the primaries. For massive primaries the luminosity and stellar mass functions of satellites are similar in shape to those of field galaxies, but for lower mass primaries they are significantly steeper. The steepening is particularly marked for the stellar mass function. Satellite abundance increases strongly with primary stellar mass, approximately in proportion to expected dark halo mass. Massive red primaries have up to a factor of 2 more satellites than blue ones of the same stellar mass. Satellite galaxies are systematically redder than field galaxies of the same stellar mass. Satellites are also systematically redder around more massive primaries. At fixed primary mass, they are redder around red primaries. We select similarly isolated galaxies from mock catalogues based on the simulations of Guo et al.(2011) and analyze them in parallel with the SDSS data. The simulation reproduces all the above trends qualitatively, except for the steepening of the satellite luminosity and stellar mass functions. Model satellites, however, are systematically redder than in the SDSS, particularly at low mass and around low-mass primaries. Simulated haloes of a given mass have satellite abundances that are independent of central galaxy colour, but red centrals tend to have lower stellar masses, reflecting earlier quenching of their star formation by feedback. This explains the correlation between satellite abundance and primary colour in the simulation. The correlation between satellite colour and primary colour arises because red centrals live in haloes which are more massive, older and more gas-rich, so that satellite quenching is more efficient.Comment: 29 pages, 24 figure
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