Recently performed environmental risk assessments of ivermectin demonstrated the need to complete the information regarding the fate of ivermectin in environment. There is also a lack of information concerning the fate and stability of praziquantel. The forced degradation study and photocatalytic degradation pathways in aqueous TiO2 suspensions of the two anthelmintics ivermectin and praziquantel were investigated and compared. The degradation efficiency increased for both compounds with the increase in the TiO2 concentration from 0.25 to 2.00 g L(-1), and then remained constant. The estimated k-values were from 0.36 h(-1) to 0.64 h(-1) for IVE and from 0.29 h(-1) to 0.47 h(-1) for PZQ, respectively. The degradation rate was not significantly impacted by the change of the pH value (pH 3, 5, 7, and 9) at 2.0 g L(-1) of TiO2. The photo degradation was about 90% for both compounds after 5 h of irradiation and it was significantly inhibited in the presence of iodide anion and isopropyl alcohol, which indicated, that hydroxyl radicals as well as holes contributed to the degradation of both anthelmintics. The contribution of hydroxyl radicals and holes was 92.1% for IVE and 93.2% for PZQ, respectively. Photocatalytic process of ivermectin resulted in three degradation intermediates; another two were formed during acidic and basic hydrolysis. Praziquantel underwent degradation to six degradation intermediates; four of them were formed under photocatalytic irradiation. The intermediates were identified using UHPLC-MS/MS. UV/TiO2 photolysis has been found as an effective advanced oxidation technology for the decontamination of ivermectin and praziquantel.
- MeSH
- 2-propanol chemie MeSH
- anthelmintika chemie MeSH
- chemické látky znečišťující vodu chemie MeSH
- čištění vody metody MeSH
- fotolýza MeSH
- ivermektin chemie MeSH
- jodidy chemie MeSH
- oxidace-redukce MeSH
- praziquantel chemie MeSH
- regenerace a remediace životního prostředí metody MeSH
- suspenze MeSH
- tandemová hmotnostní spektrometrie MeSH
- titan chemie účinky záření MeSH
- ultrafialové záření MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The aim of the study was the comparison of photo-activity of three types of titanium dioxide (TiO2) micro-dispersions intended for use as UV filters for cosmetic sunscreen products. The dispersions were also investigated with regard to their influence on the stability of photo-protective systems in cosmetic emulsions, their skin penetration/absorption and their photo-toxicity for humans and skin bacterial flora. All the tested micro-dispersions of rutile TiO2 type (agglomerates with diameter 120-150 nm), with primary particle size lower than 100 nm, demonstrated no phototoxic effect and insignificant antimicrobial behaviour. On the other hand, TiO2 with insufficient deactivation of photo-activity had significant negative impact on the stability of other organic UV filters and therefore on the stability of declared UV protective factors (SPF, UVA-PF). The study demonstrated that the level of deactivation of TiO2 is one of the highly important factors for evaluation of UV filters used as sunscreens.
- MeSH
- antibakteriální látky * chemie farmakologie účinky záření MeSH
- azosloučeniny chemie MeSH
- barvicí látky chemie MeSH
- benzensulfonáty chemie MeSH
- buňky 3T3 MeSH
- Escherichia coli účinky léků MeSH
- farmaceutická chemie MeSH
- kožní absorpce MeSH
- kůže metabolismus MeSH
- kyselina askorbová chemie MeSH
- myristáty chemie MeSH
- myši MeSH
- nanočástice * chemie účinky záření MeSH
- prasata MeSH
- přípravky chránící proti slunci * chemie farmakologie účinky záření MeSH
- Staphylococcus epidermidis účinky léků MeSH
- techniky in vitro MeSH
- titan * chemie farmakologie účinky záření MeSH
- ultrafialové záření MeSH
- velikost částic MeSH
- voda chemie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The paper addresses laboratory preparation and antibacterial activity testing of kaolinite/nanoTiO2 composite in respect of the daylight irradiation time. Kaolinite/nanoTiO2 composites with 20 and 40 wt% of TiO2 were laboratory prepared, dried at 105 °C and calcined at 600 °C. The calcination caused transformation of kaolinite to metakaolinite and origination of the metakaolinite/nanoTiO2 composite. X-ray powder diffraction, Raman and FTIR spectroscopic methods revealed titanium dioxide only in the form of anatase in all evaluated samples (non-calcined and calcined) and also transformation of kaolinite to metakaolinite after the calcination treatment. Scanning electron microscopy was used as a method for characterization of morphology and elemental composition of the studied samples. A standard microdilution test was used to determine the antibacterial activity using four human pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa). A lamp with a wide spectrum bulb simulating daylight was used for induction of photocatalysis. The antibacterial assays found all the KATI samples to have antibacterial potency with different onset of the activity when calcined samples exhibited antibacterial activity earlier than the non-calcined. Significant difference in antibacterial activity of KATI samples for different bacterial strains was not observed.
- MeSH
- antibakteriální látky chemie farmakologie účinky záření MeSH
- Bacteria účinky léků MeSH
- časové faktory MeSH
- kaolin chemie účinky záření MeSH
- katalýza účinky záření MeSH
- nanočástice chemie účinky záření MeSH
- nanokompozity chemie účinky záření MeSH
- povrchové vlastnosti MeSH
- světlo * MeSH
- titan chemie účinky záření MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Při současných znalostech průběhu osseointegrace dentálních implantátů máme dostatek informací o vztahu způsobu ošetření povrchu implantátu a rychlosti a kvality osseointegrace. Povrch SYNTHEGRA® je Nd:YAG LASERem vytvořený, geometricky přesně definovaný povrch, který není v průběhu výroby kontaminován žádnou další chemickou substancí, neboť ke zdrsnění povrchu dochází vaporizací titanu po působení laserových impulsů na povrch implantátu. Tímto patentovaným způsobem je v současné době ošetřen pouze jediný typ implantátu – WAY, který existuje ve třech variantách: bone level, transmukózní implantát a implantát se zevním hexagonem.
