80 research outputs found
Condylar position and mandibular function after bilateral sagittal split osteotomy
The purpose of this retrospective study was to perform an evaluation of postoperative positional changes of the condyle and mandibular function after bilateral sagittal split osteotomy (BSSO) with manual proximal segment positioning. PATIENTS: 45 patients were divided into the 2 groups 舐 G1 (advancement 舐 14 patients) and G2 (setback–31 patients). Rigid internal fixation screws were utilized in all cases. Inclusion criteria were only BSSO, no TMJ symptoms preoperatively and age 18 or older. RESULTS: The differences between pre- and postoperative condyle position were evaluated using measurements taken from preoperative CT scans and compared to CT scans made a minimum of 6 months postoperatively. The positional changes in both the axial and sagittal planes were measured and compared. The recovery of mandibular function was evaluated by measuring maximal interincisal opening (MIO). The results revealed that condylar positional changes after BSSO in both groups were minimal and not significantly different for all three dimensions measured. The recovery of mandibular function was faster in the group G2 than in the group G1
Physical properties and cytotoxicity of Cu(ii) and Zn(ii) complexes with a TMS-substituted indolo[2,3-c]quinoline-derived Schiff base
The incorporation of non-native chemical elements, such as silicon, into drug molecules has gained significant attention as a strategy to broaden the chemical space in medicinal chemistry and develop novel drug candidates. Traditionally, research has focused on the isosteric replacement of a carbon atom with silicon ("silicon switch") in known drug structures or the attachment of a trimethylsilyl (TMS) group to biologically active scaffolds. In this study, a TMS-substituted indoloquinoline-based Schiff base (HLTMS) and its corresponding metal complexes, Cu(HLTMS)Cl2 (1) and Zn(HLTMS)Cl2 (2), were synthesized and comprehensively characterized using elemental analysis, spectroscopic techniques (IR, UV-vis, 1H and 13C NMR for HLTMS and 2), ESI mass spectrometry and single-crystal X-ray diffraction (SC-XRD) for 1 and electron diffraction (ED) for 2. The attachment of the TMS group enhanced the lipophilicity of HLTMS, while complex formation with Cu(ii) substantially improved the antiproliferative activity. Exploitation of their intrinsic fluorescence to investigate cellular uptake and intracellular localization in cancer cells was impeded by limited solubility. Both HLTMS and 2 were found to generate reactive oxygen species under cell-free conditions in accord with their redox activity established by cyclic voltammetry. The photochemical activity of the indolo[2,3-c]quinoline-based proligand HLTMS and its complexes 1 and 2 has been disclosed. The compounds exhibited significant toxicity on various human cancer cells and disrupted the mitochondrial membrane potential, suggesting the contribution of mitochondrial dysfunction, triggered by HLTMS and its metal complexes, to their toxic effects. These findings highlight the potential of TMS-substituted Schiff bases as promising anticancer drug candidates
A Review of Photocatalysts Prepared by Sol-Gel Method for VOCs Removal
The sol-gel process is a wet-chemical technique (chemical solution deposition), which has been widely used in the fields of materials science, ceramic engineering, and especially in the preparation of photocatalysts. Volatile organic compounds (VOCs) are prevalent components of indoor air pollution. Among the approaches to remove VOCs from indoor air, photocatalytic oxidation (PCO) is regarded as a promising method. This paper is a review of the status of research on the sol-gel method for photocatalyst preparation and for the PCO purification of VOCs. The review and discussion will focus on the preparation and coating of various photocatalysts, operational parameters, and will provide an overview of general PCO models described in the literature
Photocatalytic splitting of water.
The use of photocatalysis for the photosplitting of water to generate hydrogen and oxygen has gained interest as a method for the conversion and storage of solar energy. The application of photocatalysis through catalyst engineering, mechanistic studies and photoreactor development has highlighted the potential of this technology, with the number of publications significantly increasing in the past few decades. In 1972 Fujishima and Honda described a photoelectrochemical system capable of generating H2 and O2 using thin-film TiO2. Since this publication, a diverse range of catalysts and platforms have been deployed, along with a varying range of photoreactors coupled with photoelectrochemical and photovoltaic technology. This chapter aims to provide a comprehensive overview of photocatalytic technology applied to overall H2O splitting. An insight into the electronic and geometric structure of catalysts is given based upon the one- and two-step photocatalyst systems. One-step photocatalysts are discussed based upon their d0 and d10 electron configuration and core metal ion including transition metal oxides, typical metal oxides and metal nitrides. The two-step approach, referred to as the Z-scheme, is discussed as an alternative approach to the traditional one-step mechanism, and the potential of the system to utilise visible and solar irradiation. In addition to this the mechanistic procedure of H2O splitting is reviewed to provide the reader with a detailed understanding of the process. Finally, the development of photoreactors and reactor properties are discussed with a view towards the photoelectrochemical splitting of H2O
Inverse polarity of the resistive switching effect and strong inhomogeneity in nanoscale YBCO-metal contacts
Visible-light-responsive surface-modified TiO2 powder with 4-chlorophenol: A combined experimental and DFT study
The visible-light-responsive inorganic-organic hybrid was prepared by surface modification of commercial TiO2 powder (Degussa P25) with 4-chlorophenol (4-CP). The optical absorption of the hybrid material is red-shifted compared to unmodified TiO2 powder due to the surface charge transfer complex (CTC) formation. The experimental results are supported by the density functional theory (DFT) calculations of the corresponding model cluster. The calculated electronic excitation spectrum is in agreement with the measured reflection spectrum of surface-modified TiO2 powder with 4-CP. The paramagnetic species, generated in the unmodified and surface modified TiO2 powders upon excitation with ultraviolet and visible light, were identified using low-temperature electron paramagnetic resonance (EPR) spectroscopy. The formation of trapped electrons (Ti(III) centers) and the persistent oxygen-centered organic radicals indicated the photoinduced electron transfer from the chemisorbed 4-chlorophenol to the conduction band of TiO2
Visible-light activated titania perovskite photocatalysts: Characterisation and initial activity studies
EPR investigations of polymeric and H2O2 -modified C3N4 -based photocatalysts
The C3N4 -based nanopowders prepared by thermal condensation of melamine (MCN) with subsequent thermal etching (MCN-TE) and H2O2 -treatment were investigated by Q- and X-band EPR spectroscopy in dark and upon in situ UVA or visible-light exposure. Lorentzian signal at g = 2.003, more pronounced in the case of the thermally etched material, dominates EPR spectra of MCN and MCN-TE. More complex spectra were found for H2O2 -treated photocatalysts revealing the presence of signals attributed to the radicals produced via H2O2 interaction with C/N sites in the C3N4 polymeric network. The X-band spectra monitored upon in situ irradiation of the C3N4 -based photocatalysts evidenced the intensity growth of the single line at g = 2.0033 indicating the photoinduced generation of electrons in localized paramagnetic states with the Curie dependence on temperature in the temperature range 100–180 K. The response towards UV or visible-light exposure was significantly limited in the case of H2O2 -treated photocatalysts. EPR spin trapping experiments performed in aqueous suspensions demonstrated the formation of HO2[rad] and HO [rad] spin-adducts, and the increased stability of the primary photogenerated O2 javax.xml.bind.JAXBElement@3a251187 – in aprotic media was well documented by the irradiation of the photocatalysts in the dimethylsulfoxide/water mixed solvent. The highest activities in the production of the non-persistent radical species spin-adducts were found for the thermally etched and pristine photocatalysts, confirming the negative effect of H2O2 -treatment
- …
