CeO2
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In this study, CeO2 (cerium oxide) nanoparticles were synthesized using Pinus halepensis pollen and were characterized by field emission scanning electron microscopy (FESEM), powder X-ray diffraction (PXRD) and Raman spectroscopy. The results showed that the ensuing CeO2 nanostructures, ranging in size from 5 to 25 nm, had high porosity. Synthesized CeO2 showed the effective catalytic activity towards the photocatalytic removal of dyes. In this work, the photocatalytic activity to removal dye (methyl violet 2B), in the absence of UV radiation, using cerium dioxide nanoparticles (CeO2-NP) was determined. In this research, four main factors such as effect on color, concentration and pH were examined and maximum %R was obtained about was 97% in 75 min in presence of 50 mg of hydrogen peroxide.
- MeSH
- barvicí látky chemie izolace a purifikace MeSH
- borovice MeSH
- cer chemie MeSH
- nanostruktury chemie MeSH
- poréznost MeSH
- Publikační typ
- časopisecké články MeSH
Neadekvátnost mozkové perfuze při řízené hypotenzi se může podílet na vzniku mozkové ischemie. Jedenácti nemocným ASA I-II podstupujících plánovanou neurochirurgickou operaci mozkového aneurysmatu byl předoperačně zaveden katétr do jugulámího bulbu ke sledování hodnot saturace krve jugulámího bulhu (Sj02), mozkové extrakce kyslíku (CEO2) a lakíátu v průběhu řízené hypotenze (ŘH). K řízené hypotenzi byl použit nitroprusid sodný, cílová hodnota středního arteriálního tlaku byla 50-55 mmHg. V hodnotách SjO2 a CEO2 nebyly rozdíly v průběhu ŘH v porovnání s hodnotami před jejím zahájením. Signifikantně vyšší hladiny laktátu z krve jugulámího bulbu byly zaznamenány po ukončení ŘH v porovnám s hodnotami před zahájením RH a vjejímprůběhu. Nebyla zjištěna korelace mezi hodnotami MAP a Sj02 v průběhu ŘH. Jugulárníoxymetrii nelze považovat za přínosnou v hodnocení adekvátnosti mozkové perfuze v průběhu řízené hypotenze u nemocných s předpokladem zachované autoregulace mozkového řečiště.
Non-adequacy of brain tissue perfusion during induced hypotension may contribute to cerebral ischemia. Jugular bulb catheter was inserted in eleven patients scheduled for neurosurgical repair of aneurysm, to allow monitoring of blood oxygen saturation in jugular bulb (SJO2), cerebral oxygen lactate levels during induced hypotension. Sodium nitroprusside was used to induced hypotension with target MAP 50 - 55 mmHg. During induced hypotension there were no differences in SJO2 and CEO2 values compared to .similar values prior to induction of hypotension. Significantly higher lactate levels from jugular bulb were obtained after the re.storationfrom induced hypotension, compared to values prior to and during induced hypotension. There was not found a correlation between MAP levels and SJO2 values during induced hypotension. Jugular bulb oximetry can not be consider beneficial in assessing the adequacy of cerebral perfusion during induced hypotension in patients with preserved autoregulation of cerebral circulation.
Nanocrystalline cerium dioxide is able to protect living cells from oxidative stress under the influence of various stress factors, in particular under the one of low temperatures. This study investigates the phase-structural transformations in aqueous solutions containing CeO2 nanoparticles (NPs) and their impact on the cryopreservation process. Differential scanning calorimetry and thermomechanical analysis were used to analyse the phase transitions in aqueous suspensions of CeO2 NPs and aqueous solutions of the cryoprotectant dimethyl sulfoxide (Me2SO) with CeO2 NPs. Various concentrations of CeO2 NPs were tested to observe their effects on the crystallization and melting behaviours. The addition of CeO2 NPs significantly altered the temperatures and enthalpies of melting and crystallization in water. Low concentrations of CeO2 NPs promoted crystallization, while higher concentrations inhibited it, reducing supercooling and recrystallization during thawing. In Me2SO solutions, CeO2 NPs raised the glass transition temperature and affected the recrystallization process, with higher concentrations leading to more pronounced vitrification and reduced recrystallization. We also investigated the regularities of the effect of CeO2 NPs on phase transitions in combined cryoprotective media with Ham's F12, fetal bovine serum and Me2SO, which can be used in future to design the cryopreservation protocols. In the complex media, CeO2 NPs decreased the metastability and altered eutectic crystallization patterns, indicating potential cryoprotective effects. In conclusion, CeO2 NPs modulate the thermophysical properties of cryoprotective solutions, enhancing vitrification and reducing recrystallization, which could improve cryopreservation efficiency. Optimizing NP concentrations is crucial for practical applications in cryopreservation.
- MeSH
- cer * chemie farmakologie MeSH
- diferenciální skenovací kalorimetrie * MeSH
- dimethylsulfoxid * chemie MeSH
- kryoprezervace * metody MeSH
- kryoprotektivní látky * chemie farmakologie MeSH
- krystalizace * MeSH
- nanočástice * chemie MeSH
- tranzitní teplota MeSH
- vitrifikace * účinky léků MeSH
- změna skupenství * MeSH
- Publikační typ
- časopisecké články MeSH
A multistep sample preparation method was developed to separate metal-based engineered nanoparticles (ENPs) from biological samples. The method was developed using spiked zebrafish tissues and standard titanium dioxide (TiO2) and cerium dioxide (CeO2) ENPs. Single-particle inductively coupled plasma mass spectrometry was used to quantify the separated particles in terms of number concentration. This method demonstrated mass recoveries of more than 90% and did not strikingly alter the median particles size. High number recoveries were calculated for CeO2 ENPs (>84%). Particle number recoveries were poor for TiO2 ENPs (<25%), which could be due to the interference of 48Ca with the measured isotope 48Ti. The method was verified using zebrafish exposed to CeO2 ENPs to test its applicability for nanotoxicokinetic investigations. Total mass of Ce and particle number concentration of CeO2 ENPs were measured in different tissues. Notably, the mass-based biodistribution of Ce in the tissues did not follow the number-based biodistribution of CeO2. Moreover, the calculated mass-based bioconcentration factors showed a different pattern in comparison to the number-based bioconcentration factors. Our findings suggest that considering mass as the sole dose-metric may not provide sufficient information to investigate toxicity and toxicokinetics of ENPs.
Magnetic γ-Fe2O3/CeO2 nanoparticles were obtained by precipitation of Ce(NO3)3 with ammonia in the presence of γ-Fe2O3 seeds. The formation of CeO2 nanoparticles on the seeds was confirmed by transmission electron microscopy linked with selected area electron diffraction, energy-dispersive X-ray spectroscopy, electron energy loss spectroscopy, and dynamic light scattering. The γ-Fe2O3/CeO2 particle surface was functionalized with PEG-neridronate to improve the colloidal stability in PBS and biocompatibility. Chemical and in vitro biological assays proved that the nanoparticles, due to the presence of cerium oxide, effectively scavenged radicals, thus decreasing oxidative stress in the model cell line. PEG functionalization of the nanoparticles diminished their in vitro aggregation and facilitated lysosomal cargo degradation in cancer cells during autophagy, which resulted in concentration-dependent cytotoxicity of the nanoparticles. Finally, the iron oxide core allowed easy magnetic separation of the particles from liquid media and may enable monitoring of nanoparticle biodistribution in organisms using magnetic resonance imaging.
This study was a comparison between Ru-catalysts and similar, previously investigated, Pt-catalysts. In this paper, ruthenium catalysts for catalytic wet air oxidation are prepared, characterized and tested. Both catalysts were supported on commercial CeO2 as well as mixed oxide Zr(0.1)(Ce(0.75)Pr(0.25))(0.9)O2. The catalysts were characterized by measuring the oxygen storage capacities (OSC), BET, XRD, FTIR and chemisorption of hydrogen. In addition, the effect of sintering (treatments under H2) was compared with both of the catalysts. The comparison of the results showed that initial intrinsic activity of ruthenium is not significantly influenced by the type of the support, which is contrast to platinum. Furthermore, the particle size of Ru had an important effect on CWAO activity: the higher the particle size, the better the activity. This was different with Pt-catalysts, where the optimal particle size was smaller, having about 15% of metal dispersion.
- MeSH
- cer MeSH
- katalýza MeSH
- kyselina octová chemie MeSH
- oxidace-redukce MeSH
- oxidy MeSH
- platina MeSH
- ruthenium MeSH
- velikost částic MeSH
- vzduch MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
