Although the nitrous oxide belongs among three of the most contributing greenhouse gases to global warming, it is quite neglected by photocatalytic society. The g-C3N4 and WO3 composites were therefore tested for the photocatalytic decomposition of N2O for the first time. The pure photocatalysts were prepared by simple calcination of precursors, and the composites were prepared by mixing of suspension of pure components in water followed by calcination. The structural (X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy), textural (N2 physisorption), and optical properties (diffuse reflectance spectroscopy, photoluminescence spectroscopy, photoelectrochemical measurements) of all composites were correlated with photocatalytic activity. The experimental results and results from characterization techniques confirmed creation of Z-scheme in the WO3/g-C3N4 composites, which was confirmed by hydroxyl radicals' trapping measurements. The photocatalytic decomposition of N2O was carried out in the presence of UVA light (peak intensity at 365 nm) and the 1:2 WO3/g-C3N4 composite was the most active one, but the photocatalytic activity was just negligibly higher than that of pure WO3. This is caused by relatively weak interaction between WO3 and g-C3N4 which was revealed from XPS.
Time-resolved microspectrofluorimetry and fluorescence microscopy imaging-two complementary fluorescence techniques-provide important information about the intracellular distribution, level of uptake and binding/interactions inside living cell of the labeled molecule of interest. They were employed to monitor the "fate" of AS1411 aptamer labeled by ATTO 425 in human living cells. Confocal microspectrofluorimeter adapted for time-resolved intracellular fluorescence measurements by using a phase-modulation principle with homodyne data acquisition was employed to obtain emission spectra and to determine fluorescence lifetimes in U-87 MG tumor brain cells and Hs68 non-tumor foreskin cells. Acquired spectra from both the intracellular space and the reference solutions were treated to observe the aptamer localization and its interaction with biological structures inside the living cell. The emission spectra and the maximum emission wavelengths coming from the cells are practically identical, however significant lifetime lengthening was observed for tumor cell line in comparison to non-tumor one.
- MeSH
- aptamery nukleotidové metabolismus MeSH
- časové faktory MeSH
- fluorescenční mikroskopie metody MeSH
- fluorescenční spektrometrie metody MeSH
- intracelulární prostor genetika metabolismus MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- oligodeoxyribonukleotidy genetika metabolismus MeSH
- sekvence nukleotidů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In the title method, nitrates are determined in mineralizates by measuring the difference in absorbances at 216 and 218 nm. Thus the effect of incomplete decomposition of the sample matrix is eliminated. The simple, rapid and inexpensive method combining the oxidation mineralization and UV photometry is suitable for analysis of large series of water samples. The yield of oxidative mineralization of NH3 decreases at concentrations higher than 5 mg l-?1. An addition of CH2O eliminates the loss of NH3 due to the formation of NH3-CH2O condensation products.
Time-resolved confocal microspectrofluorometry and fluorescence microscopy imaging were applied to monitor the cellular uptake of fluorescent-labeled oligonucleotides (ONs) delivered by a porphyrin molecule. The fate of porphyrin-ON complexes inside living cells has also been monitored. Due to intrinsic fluorescence of the porphyrin and sensitivity of its characteristics to microenvironment, multicomponent analysis of time-resolved fluorescence provides unique information about stability of the porphyrin-ON complexes, ON interactions with their target sequences, and ON and porphyrin distributions after delivery inside the cells. Time-resolved confocal microspectrofluorometry indeed delivers additional information compared with fluorescence confocal microscopy imaging widely employed to study ON uptake.
- MeSH
- antisense oligonukleotidy chemie MeSH
- buněčné jádro metabolismus MeSH
- buňky 3T3 MeSH
- časové faktory MeSH
- financování organizované MeSH
- fluorescence MeSH
- fluorescenční mikroskopie metody přístrojové vybavení MeSH
- kationty MeSH
- konfokální mikroskopie metody přístrojové vybavení MeSH
- lékové transportní systémy MeSH
- melanom experimentální MeSH
- myši MeSH
- oligonukleotidy chemie MeSH
- porfyriny chemie MeSH
- senzitivita a specificita MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- přehledy MeSH
Cationic 5,10,15,20-tetrakis (1-methyl-4-pyridyl) porphyrin was tested as a delivery agent for oligonucleotides. By using fluorescence microimaging, it has been shown that complexation of the porphyrin to the phosphorothioate analog of dT(15) labeled by rhodamine enabled its nonendocytic penetration into the cell and regular distribution in the cytoplasm and preferentially into the nucleus. Time-resolved microfluorescence spectroscopy revealed that the oligonucleotide integrity was kept. A small fraction of the porphyrin molecules seems to undergo change of the binding mode after internalization, probably due to duplex formation between the oligonucleotide and its cellular target sequences, or due to dissociation of the porphyrin from the oligonucleotide and subsequent interactions in the cellular environment. (c) 2006 Wiley Periodicals, Inc.
- MeSH
- amfotericin B farmakologie MeSH
- buněčná membrána metabolismus MeSH
- buněčné jádro metabolismus MeSH
- cytoplazma metabolismus MeSH
- finanční podpora výzkumu jako téma MeSH
- fluorescenční spektrometrie metody MeSH
- kationty MeSH
- myši MeSH
- oligonukleotidy farmakokinetika MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
