38 research outputs found
Modern Markers of Organ Damage in Clinical Practice
Pravidelná fyzická aktivita je prokázanou součástí zdravého životního stylu. Nepřiměřená fyzická zátěž však může vést k subjektivním a objektivním příznakům, které dovedou sportovce k lékaři. Hospitalizace z kardiálních i nekardiálních příčin po výraznější zátěži, např. po dokončení půlmaratonu, není vzácná, dokonce ani u mladých jedinců. Markery poškození orgánů, které se v klinické praxi používají, mohou mít po fyzické zátěži interpretační limity, na které nejsou lékaři zvyklí. Zároveň se objevují nové markery nebo vylepšené generace zavedených ukazatelů a studie zaměřené na hledání jejich vztahů s parametry trénovanosti, zátěže a zobrazovacími vyšetřeními mohou přispět k lepšímu pochopení a správnější interpretaci. Zejména práce založené na sledování hladin markerů poškození orgánů po standardizované zátěži jsou poměrně vzácné. Naším cílem bylo popsat dynamiku a vztahy vybraných klinicky používaných markerů poškození orgánů po extrémní fyzické zátěži v soutěžním prostředí a standardizované vytrvalostní zátěži v kontrolovaných laboratorních podmínkách. Ve spolupráci s Ústavem tělovýchovného lékařství a kardiologickým oddělením jsme provedli 2 studie. Cílem naší první práce bylo posoudit vliv extrémní běžecké zátěže na hodnoty vysoce senzitivního troponinu I (hsTnI), galektinu-3, ultrasenzitivního CRP...Physical activity is a useful tool in the prevention of many diseases. Hospitalization after strenuous exercise from cardiac or noncardiac causes, even in young athletes without previous symptoms, can occur. These situations are not uncommon and e.g. after completing a half- marathon clinical symptoms suspicious from cardiac etiology can be present. Limitations of biomarkers used in daily clinical practice can lead to misinterpretation with additional consequences to the patient's outcome. Our goal was to describe changes of markers used in daily clinical practice after extreme physical activity and after exercise under laboratory conditions. We performed two studies in cooperation with Department of cardiology and Department of sports medicine. The goal of our first study was to examine high sensitivity troponin I (hsTnI), galectin-3, cystatin C, NGAL and ultrasensitive CRP (uCRP) after extremely long run during the competition in long distance running. The goal of our second study was to examine high- sensitivity troponin T (hsTnT) and hsTnI, creatinine and cystatin C, and urine albumin and NGAL after a standardized two-hour treadmill run under laboratory conditions and to find possible connection with echocardiographic, laboratory and other assessed parameters. The second goal of study under laboratory...Ústav klinické biochemie a hematologieLékařská fakulta v PlzniFaculty of Medicine in Pilse
On thermal stability of nanocrystalline Ag–Cu-S powders
The nanocrystalline semiconducting compounds based on the AgCuS system are considered as low-cost candidates of thermoelectric materials with improved thermal stability. The nanocrystalline Ag–Cu—S powders were prepared from metal nitrates and sulphur powder in tetraethylene glycol (TEG) solvent by reductive agent NaBH4. The crystallite sizes of the observed phases were in the range between 60 and 80 nm. The chemical compositions of the as-received samples were analysed by the ICP-AES method and their phase compositions were evaluated by XRPD. The investigation was supplemented by DSC and in situ HTXRD thermal analysis. A more detailed in situ experiment was performed for a sample containing ternary phases. The nucleation and growth of silver micro-wires were first observed on the substrate involving ternary phases at isothermal heat treatment. The formation of silver wires and semi-conductive ternary thermoelectric phase (stromayerite τ3) is explained by observed phase transformation. The obtained results are complemented by microscopy (LM, SEM, TEM)
Ag-Cu Colloid Synthesis: Bimetallic Nanoparticle Characterisation and Thermal Treatment
The Ag-Cu bimetallic colloidal nanoparticles (NPs) were prepared by solvothermal synthesis from metalloorganic precursors in a mixture of organic solvents. The nanoparticles were characterized by dynamic light scattering (DLS) and small angle X-ray scattering (SAXS). The properties of metallic core and organic shell of the nanoparticles were studied by direct inlet probe mass spectrometry (DIP/MS), Knudsen effusion mass spectrometry (KEMS), double-pulse laser-induced breakdown spectroscopy (DPLIBS), and differential scanning calorimetry (DSC). The transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used for particle characterization before and after thermal analysis. The experiment yielded results that were for AgCu nanoparticles for the first time. The detected liquidus temperature has been compared with the prediction obtained from calculation of the phase diagram of Ag-Cu nanoalloy. The experimental results show that of near-eutectic composition AgCu nanoparticles possess the fcc crystal lattice. Surprisingly, spinodal decomposition was not observed inside the AgCu nanoparticles at temperatures up to 230C. The depression of the eutectic AgCu melting point was calculated but not observed. The eutectic AgCu microparticles are formed before melting.Ag-Cu bimetalické koloidní nanočástice (NPs) byly připraveny solvotermální syntézou z metalických prekurzorů ve směsi organických rozpouštědel. Nanočástice byly charakterizovány metodami: DLS a SAXS. Vlastnosti kovového jádra a stabilizační obálky z organických látek byly studovány metodou přímého vstupu do hmotnostního spektrometru (DIP/MS), Knutsenovou hmotnostní spektrometrií (KEMS), double -pulse laserovou spektroskopií (DPLIBS) a diferenční skenovací kalorimetrií (DSC). Transmisní elektronová mikroskopie (TEM) a řádkovací elektronová mikroskopie (SEM) byly použity pro charakterizaci částic před a po termické analýze. Teplota likvidu zjištěna experimentálně byla srovnávána s predikcí fázového diagramu Ag-Cu nanoslitiny. Experimentální výsledky ukázaly téměř eutektické složení a fcc krystalovou mřížku AgCu NPs. Překvapivě, spinodální rozklad nanočástic nebyl pozorován při teplotách do 230C
Mechanical and electrical properties of ternary Ag-Bi-Ga system at 250 °C
This paper presents a comparative review of the experimental and thermodynamic assessment of a ternary Ag-Bi-Ga system. An isothermal section at 250 °C was calculated using optimized thermodynamic data for the constitutive binaries. Microstructures and phase compositions of studied alloys were analyzed by scanning electron microscopy in combination with energy dispersive spectrometry and X-ray powder diffraction technique. The obtained experimental results were found to support the predicted phase equilibria rather well. The hardness of alloys from three vertical sections (Bi-AgGa, Ag-BiGa, and Ga-AgBi) was determined using Brinell hardness test while the hardness of the individual identified phases was determined using Vickers microhardness test. Additional electrical conductivity measurements were carried out on the same alloy samples. Based on the experimentally obtained results iso-lines of Brinell hardness and electrical conductivity for the entire compositional range were calculated
Au-Ni nanoparticles: Phase diagram prediction, synthesis, characterization, and thermal stability
The Au-Ni nanoparticles (NPs) were prepared by oleylamine solvothermal synthesis from metal precursors. The Au-Ni phase diagram prediction respecting the particle size was calculated by the CALPHAD method. The hydrodynamic size of the AuNi NPs in a nonpolar organic solvent was measured by the dynamic light scattering (DLS) method. The average hydrodynamic sizes of the nanoparticle samples were between 18 and 25 nm. The metallic composition of the AuNi NP samples was obtained by inductively-coupled plasma atomic emission spectroscopy (ICP-OES). The metallic fraction inside AuNi NPs was varied Au-(30-70)wt%Ni. The steric alkylamine stabilization was observed. The individual AuNi NPs were investigated by transmission electron microscopy (TEM). The dry nanopowder was also studied. The structures of the aggregated samples were investigated by scanning electron microscopy (SEM). The AuNi NPs reveal randomly mixed face-centered cubic (FCC) crystal lattices. The phase transformations were studied under inert gas and air. The samples were studied by differential scanning calorimetry (DSC).Nanočástice Au-Ni (NPs) byly připraveny solvotermální syntézou z kovových prekurzorů. Predikce fázového diagramu Au-Ni s ohledem na velikost částic byla vypočítána metodou CALPHAD. Hydrodynamická velikost AuNi NP v nepolárním organickém rozpouštědle byla měřena metodou dynamického rozptylu světla (DLS). Průměrné hydrodynamické velikosti vzorků nanočástic byly mezi 18 a 25 nm. Chemické složení kovů vzorků AuNi NP bylo získáno indukčně vázanou plazmovou atomovou emisní spektroskopií (ICP-OES). Kovová frakce uvnitř AuNi NP byla různá v rozmězí Au-(30-70hm%)Ni. Byla pozorována sterická stabilizace alkylaminem. Jednotlivé NP AuNi byly zkoumány tramsmisní elektronovou mikroskopií (TEM). Také byl zkoumán suchý nanoprášek. Struktury agregovaných vzorků byly zkoumány pomocí skenovací elektronové mikroskopie (SEM). AuNi nanočástice vykazovaly krystalovou mřížku náhodně smíšeného tuhého roztoku (FCC). Fázové transformace byly studovány pod inertním plynem a na vzduchu. Vzorky byly také studovány diferenční skenovací kalorimetrií (DSC)
On the constitution and thermodynamic modeling of the phase diagrams Nb-Mn and Ta-Mn
The constitution of the two phase diagrams Nb-Mn and Ta-Mn has been determined from light optical and transmission and scanning electron microscopy (LOM, TEM and SEM) with energy dispersive (EDX) as well as wavelength dispersive (WDX) X-ray spectroscopy, X-ray powder (XPD) and single crystal diffraction (XSCD), differential thermal analysis (DTA) and/or differential scanning calorimetry (DSC). The Laves phases NbMn2 and TaMn2 are the only binary compounds in these systems. High-temperature differential thermal analyses revealed congruent melting for NbMn2 with T,(NbMn2) = 1515 +/- 15 degrees C, whereas TaMn2 melts incongruently with T-m(TaMn2)= 1797 +/- 40 degrees C close to a depleted peritectic reaction. Both Laves phases engage in eutectic reactions l (Mn) + Nb(Ta)Mn-2 (T-eut = 1220 +/- 10 degrees C at 4.9 at% Nb and T-eut = 1234 +/- 10 degrees C at 0.7 at% Ta, respectively). NbMn2 also forms a eutectic with (Nb): l (Nb) + NbMn2 at T-eut = 1493 +/- 15 degrees C and 53.2 at% Nb. Mn shows remarkably large maximum solid solubilities of 19.4 at% Mn in (Nb) as well as of 21.3 at% Mn in (Ta). Detailed atom site distribution has been established for the Laves phases by means of temperature dependent X-ray single crystal data (both C14 - MgZn2-type). Combined data from XPD, EDX/WDX and SEM microstructure indicate that for both Laves phases extended homogeneity regions exist: Nb1+xMn2+x (62.5-73.0 at% Mn at 950 degrees C: -0.19 <= x <= 1.125) and Ta1+xMn2-x (59.5-68.5 at % Mn: -0.055 <= x <= 1.215). Density functional theory (DFT) calculations favor Nb(Ta)/Mn antisite occupation rather than defects. The phases, "NbMn" and "TaMn", adopted earlier in the literature as binary system inherent compounds, were shown (TEM, WDX electron microprobe data and X-ray Rietveld refinements) to be oxygen stabilized phases of the Ti4Ni2O type (so-called eta(eta)-phases) with modified Nb(Ta)/Mn site substitution to comply with the formula Nb(Ta)(3-x)Mn3+xO1-y (defect eta-W3Fe3C-type). From magnetic susceptibility and magnetization measurements, both oxide stabilized eta phases eta-Nb3Mn3O1-y and eta-Ta3Mn3O1-y were found to order ferromagnetically below T-c similar to 77 K, but the Laves phases NbMn2, TaMn2 reveal weakly temperature dependent paramagnetism. No trace of the rhombohedral kyphase (W6Fe7-type) has been encountered in our investigation of the two binary phase diagrams. Thermodynamic and transport properties (specific heat, electrical resistivity and magnetic susceptibility/magnetization) classify the Laves phases with metallic behavior whilst mechanical properties (elastic moduli from DFT and nanoindentation as well as hardness and thermal expansion) group both Laves phases among rather hard and brittle intermetallics.
Based on (i) the experimentally derived constitution of the Nb-Mn and Ta-Mn systems, and (ii) on new own DFT data of the energy of formation of the Laves phases, a CALPHAD (CALculation of PHAse Diagrams) calculation of both systems was made providing a complete set of optimized thermodynamic data. Furthermore, the DFT calculations provided information on the instability of the eta-Ta3Mn3 structure and the atom-site specific stabilization effect of oxygen.Web of Science865art. no. 15871
Binary asteroid (31) Euphrosyne: ice-rich and nearly spherical
Aims. Asteroid (31) Euphrosyne is one of the biggest objects in the asteroid main belt and it is also the largest member of its namesake family. The Euphrosyne family occupies a highly inclined region in the outer main belt and contains a remarkably large number of members, which is interpreted as an outcome of a disruptive cratering event. Methods. The goals of this adaptive-optics imaging study are threefold: to characterize the shape of Euphrosyne, to constrain its density, and to search for the large craters that may be associated with the family formation event. Results. We obtained disk-resolved images of Euphrosyne using SPHERE/ZIMPOL at the ESO 8.2 m VLT as part of our large program (ID: 199.C-0074, PI: Vernazza). We reconstructed its 3D shape via the ADAM shape modeling algorithm based on the SPHERE images and the available light curves of this asteroid. We analyzed the dynamics of the satellite with the Genoid meta-heuristic algorithm. Finally, we studied the shape of Euphrosyne using hydrostatic equilibrium models. Conclusions. Our SPHERE observations show that Euphrosyne has a nearly spherical shape with the sphericity index of 0.9888 and its surface lacks large impact craters. Euphrosyne’s diameter is 268 ± 6 km, making it one of the top ten largest main belt asteroids. We detected a satellite of Euphrosyne – S/2019 (31) 1 – that is about 4 km across, on a circular orbit. The mass determined from the orbit of the satellite together with the volume computed from the shape model imply a density of 1665 ± 242 kg m−3, suggesting that Euphrosyne probably contains a large fraction of water ice in its interior. We find that the spherical shape of Euphrosyne is a result of the reaccumulation process following the impact, as in the case of (10) Hygiea. However, our shape analysis reveals that, contrary to Hygiea, the axis ratios of Euphrosyne significantly differ from those suggested by fluid hydrostatic equilibrium following reaccumulation.This work has been supported by the Czech Science Foundation through grant 18-09470S (J. Hanuš, O. Chrenko, P. Ševeček) and by the Charles University Research program No. UNCE/SCI/023. M.B. was supported by the Czech Science Foundation grant 18-04514J. Computational resources were supplied by the Ministry of Education, Youth and Sports of the Czech Republic under the projects CESNET (LM2015042) and IT4Innovations National Supercomputing Centre (LM2015070). P. Vernazza, A. Drouard, M. Ferrais and B. Carry were supported by CNRS/INSU/PNP. M.M. was supported by the National Aeronautics and Space Administration under grant No. 80NSSC18K0849 issued through the Planetary Astronomy Program. The work of TSR was carried out through grant APOSTD/2019/046 by Generalitat Valenciana (Spain). This work was supported by the MINECO (Spanish Ministry of Economy) through grant RTI2018-095076-B-C21 (MINECO/FEDER, UE). The research leading to these results has received funding from the ARC grant for Concerted Research Actions, financed by the Wallonia-Brussels Federation. TRAPPIST is a project funded by the Belgian Fonds (National) de la Recherche Scientifique (F.R.S.-FNRS) under grant FRFC 2.5.594.09.F. TRAPPIST-North is a project funded by the Université de Liège, and performed in collaboration with Cadi Ayyad University of Marrakesh. E. Jehin is a FNRS Senior Research Associate
A basin-free spherical shape as an outcome of a giant impact on asteroid Hygiea
(10) Hygiea is the fourth largest main belt asteroid and the only known asteroid whose surface composition appears similar to that of the dwarf planet (1) Ceres1,2, suggesting a similar origin for these two objects. Hygiea suffered a giant impact more than 2 Gyr ago3 that is at the origin of one of the largest asteroid families. However, Hygeia has never been observed with sufficiently high resolution to resolve the details of its surface or to constrain its size and shape. Here, we report high-angular-resolution imaging observations of Hygiea with the VLT/SPHERE instrument (~20 mas at 600 nm) that reveal a basin-free nearly spherical shape with a volume-equivalent radius of 217 ± 7 km, implying a density of 1,944 ± 250 kg m−3 to 1σ. In addition, we have determined a new rotation period for Hygiea of ~13.8 h, which is half the currently accepted value. Numerical simulations of the family-forming event show that Hygiea’s spherical shape and family can be explained by a collision with a large projectile (diameter ~75–150 km). By comparing Hygiea’s sphericity with that of other Solar System objects, it appears that Hygiea is nearly as spherical as Ceres, opening up the possibility for this object to be reclassified as a dwarf planet.P.V., A.D. and B.C. were supported by CNRS/INSU/PNP. M.Brož was supported by grant 18-04514J of the Czech Science Foundation. J.H. and J.D. were supported by grant 18-09470S of the Czech Science Foundation and by the Charles University Research Programme no. UNCE/SCI/023. This project has received funding from the European Union’s Horizon 2020 research and innovation programmes under grant agreement nos 730890 and 687378. This material reflects only the authors’ views, and the European Commission is not liable for any use that may be made of the information contained herein. TRAPPIST-North is a project funded by the University of Liège, in collaboration with Cadi Ayyad University of Marrakech (Morocco). TRAPPIST-South is a project funded by the Belgian Fonds (National) de la Recherche Scientifique (F.R.S.-FNRS) under grant FRFC 2.5.594.09.F. E.J. and M.G. are F.R.S.-FNRS Senior Research Associates
Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020
We show the distribution of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three genomic nomenclature systems to all sequence data from the World Health Organization European Region available until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation, compare the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2