Made available in DSpace on 2014-06-11T19:32:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-04-17Bitstream added on 2014-06-13T20:42:51Z : No. of bitstreams: 1 santos_ad_dr_bauru.pdf: 5050501 bytes, checksum: 953944123d570eb83506e96c96c8073d (MD5) / Os cimentos odontológicos a base de Cimento Portland, vêm desde a década passada sendo exaustivamente analisados em pesquisas científicas. Comercialmente como exemplo, temos o ProRoot MTA (Tulsa Dental, Oklahoma - USA) e o MTA-Angelus (Angelus Soluções Odontológicas, Londrina - Brazil). Ambos possuem inúmeras qualidades, porém tem inadequado tempo de presa e uma consistência que dificulta o seu manuseio por parte dos clínicos. O Grupo Vidros e Cerâmicas da UNESP - Ilha Solteira desenvolveu um cimento com as mesmas aplicações clínicas do MTA. Estudos recentes mostram que este material (denominado CER), possui propriedades físico-químicas semelhantes àquelas apresentadas pelo MTA. Atualmente tem-se tentado utilizar o cimento MTA como cimento obturador endodôntico, porém, características físicas dificultam seu uso para este fim. A proposta deste trabalho foi mostrar o desenvolvimento de um novo cimento obturador endodôntico, partindo da formulação do CER e testar algumas propriedades físico químicas deste material, tendo como comparação o cimento endodôntico comercial Sealer 26® (Dentsply Ind. E Com. Ltda., Petrópolis-Brazil). Os resultados obtidos mostraram que o cimento CEOE comparado com o Sealer 26®, tem um tempo de presa menor, maior liberação de íons, maior dureza e semelhante adesividade, solubilidade e selabilidade. / In the last decade, the dental cements based on Portland cement have been exhaustively investigated scientifically. Commercially is available the ProRoot MTA (Tulsa Dental, Oklahoma - USA) and MTA-Angelus (Angelus Soluções Dental, Londrina - Brazil) cements. In spite of the excellent physical, chemical and biological properties, one of the main disadvantages with using MTA is its extended setting time and difficult handling. Recently, the Glass and Ceramics group developed an experimental cement with the same clinical applications of MTA. Recent investigations showed that this material (entitled CER) it has physico-chemical properties similar those of the MTA. At present its biological properties are being investigated. One of the principal functions of the MTA is to seal the communications between the root and extern surface of the teeth. Recent studies have been showing that the physical characteristics of the MTA make difficult his use as root-filling cement. The purpose of this study was to developed new endodontic cement based on the formulation of the CER material. The properties evaluate in this study were: setting time, ions release, adhesion, hardness, solubility and sealing ability. The obtained results were compared with the Sealer 26® (Dentsply Ind. e Com. Ltda, Petrópolis-Brazil).

abstract: This thesis explores the potential application of the phase change material tungsten trioxide (WO3) in optical force modulation for spacecraft and satellites. It starts with a literature review of past space optical force applications as well as potential phase change materials for optical force modulation. This is followed by the theoretical model and discussions of the optical properties of a variety of materials used in the structures explored thereafter. Four planar structures were analyzed in detail. Two of the structures were opaque and the other two were semi-transparent. The first of the opaque structures was a tungsten trioxide film on aluminum substrate (WO3/Al). It was found to have a 26% relative change in radiation pressure with WO3 thickness of 200 nm. The second opaque structure was a tungsten trioxide film on silicon spacer on aluminum substrate (WO3/Si/Al). This structure was found to have a 25% relative change in radiation pressure with 180 nm WO3 and 20 nm Si. The semitransparent structures were tungsten trioxide film on undoped silicone substrate (WO3/Si), and a tungsten trioxide film on a silicone spacer on tungsten trioxide (WO3/Si/WO3). The WO3/Si structure was found to have an 8% relative change in radiation pressure with 200 nm WO3 and 50 nm Si. The WO3/Si/WO3 structure had a relative change in radiation pressure of 20% with 85 nm WO3 and 90 nm Si. These structures show promise for attitude control in future solar sailing space missions. The IKAROS mission proved the functionality of using phase change material in order to steer a space craft. This was accomplished with a 7.8% relative change in radiation pressure. However, this only occurred at a pressure change of 0.11 µN/m2 over a range of 0.4 to 1.0 µm which is approximately 77.1% of the solar spectrum energy. The proposed structure (WO3/Al) with a 26% relative change in radiation pressure with a pressure change of 1.4 µN/m2 over a range 0.4 to 1.6 µm which is approximately 80% of the solar spectrum energy. The magnitude of radiation pressure variation in this study exceeds that used on the IKAROS, showing applicability for future mission. / Dissertation/Thesis / Masters Thesis Aerospace Engineering 2020

Thesis (M.Sc. (Biochemistry)) -- University of Limpopo, 2019 / Survivin is the smallest and a well-studied member of the inhibitors of apoptosis proteins (IAPs) family, which is involved in the regulation of cell division, inhibition of both caspasedependent and -independent apoptosis in cancer cells and promotion of angiogenesis. Survivin is detectable during embryonic and foetal development but is undetectable in normal adult tissues. It is, however, expressed in transformed cell lines as well as in most common types of human cancers. Regulation of survivin remains poorly understood, and the discovery of the regulatory biomolecules, microRNAs (MiRs) present an interesting opportunity to investigate the regulation of this protein and its variants in cancers, especially breast cancer. Additionally, the expression of the survivin splice variants during cell cycle progression and apoptosis is not fully understood. The aims of this study were to investigate the role of arsenic trioxide on the expression of survivin splice variants and their specific microRNAs during cell cycle progression and apoptosis in human breast cancer MCF-7 cells. The study also aimed at ascertaining the toxicity and efficacy of using coal fly ash-derived β-cyclodextrin carbon nanospheres to deliver arsenic trioxide into the MCF-7 cells. Carbon nanospheres (CNSs) were synthesised using a chemical vapour deposition method while arsenic trioxide was deposited using wet impregnation method to form the arsenic trioxide-β-cyclodextrin carbon nanospheres (ATO-β-cyclodextrin-CNSs). The formation of the CNSs and the loading of arsenic trioxide to CNSs were confirmed using scanning electron microscopy/energy dispersive X-ray detection (SEM-EDX). The in vitro cytotoxicity effect of the β-cyclodextrin carbon nanospheres (CNSs), arsenic trioxide and arsenic trioxide-β-cyclodextrin CNSs against KMST-6 and MCF-7 cells was analysed using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyltetrazolium bromide (MTT) Assay, Muse® Count and Viability Assay and light/fluorescence microscopy. Cellular apoptosis, cell cycle analysis, Multi-Caspase activation, mitochondrial membrane potential, MAPK activation and PI3K activation were analysed using the Muse® Cell Analyser. Polymerase Chain Reaction (PCR) and Immunohistochemistry were used to analyse survivin mRNA variants and protein expression, respectively. The survivin specific MiRs were predicted using both bioinformatics platforms and literature surveys. In order to understand the applicability of delivering arsenic trioxide for the treatment of breast cancer, skin fibroblast (KMST-6) and MCF-7 cells were exposed to β-cyclodextrin CNSs. The novel β-cyclodextrin CNSs did not show any cytotoxic effect on the KMST-6 cells but demonstrated such activity against the MCF-7 cells. More so, arsenic trioxide-βcyclodextrin CNSs were found to significantly reduce the viability of the MCF-7 cells and were shown to inhibit their cell growth through the induction of apoptosis. The MTT Assay results revealed arsenic trioxide inhibited the growth of the MCF-7 cells in a concentration-dependent manner. The Muse® Cell Analyser showed that arsenic trioxide induced G2/M cell cycle arrest and promoted cellular apoptosis without any damage to the mitochondrial membrane of MCF-7 cells. Furthermore, arsenic trioxide also deactivated two survival pathways, Mitogen-Activated Protein Kinase (MAPK) and Phosphoinositide 3-Kinase (PI3K) signalling pathways in MCF-7 cells. The deactivation of the two pathways was shown to be accompanied by the upregulation of survivin 3α during arsenic trioxide-induced G2/M cell cycle arrest and apoptosis. Survivin 2B was found to be upregulated only during arsenic trioxide-induced G2/M cell cycle arrest, but downregulated during arsenic trioxide-induced apoptosis. However, wild-type survivin was highly expressed in untreated MCF-7 cells, but the expression was upregulated during arsenic trioxide-induced G2/M cell cycle arrest and was downregulated during arsenic trioxide-induced apoptosis. Survivin variant ΔEx3 was undetected in both untreated and treated MCF-7 cells. Survivin 2α was upregulated during arsenic trioxideinduced apoptosis whereas, survivin 3B was only detected in the untreated MCF-7 cells. Additionally, survivin proteins were localised in both the nuclei and cytoplasm in MCF-7 cells and highly upregulated during arsenic trioxide-induced G2/M cell cycle arrest, which can be attributed to the upregulation of survivin-2B. Using TargetScan, MIRD and mirTarbase, a few MiRs were identified and confirmed to target wild-type survivin, survivin 2B and survivin ΔEx3. These include the MiR-542-3p and MiR-335-5p, which are both upregulated during apoptosis and MiR-218-5p, which is upregulated during cell arrest. MiR-218-5p targets survivin 2B, which was upregulated during G2M cell cycle arrest. The fly ash-derived CNSs can be used to deliver arsenic trioxide for therapeutic purposes, especially against breast cancer. Most importantly, these nanoparticles induced typical apoptotic characteristics in breast cancer MCF-7 cells. Arsenic trioxide can be used as therapeutic target for breast cancer treatment and nanotechnology can be used for its delivery. This study provided the first evidence that novel survivin 2B splice variant may be involved in the regulation of arsenic trioxide-induced G2/M cell cycle arrest only. This splice variant can therefore, be targeted for therapeutic purposes against Luminal A breast cancer cells

Dissertation submitted in partial compliance with the requirements of the Master's Degree in Technology: Homoeopathy, Durban University of Technology, 2010. / The therapeutic effects of homoeopathic Arsenicum album potencies were investigated in-vitro, using human cell cultures which were previously antagonised by arsenic trioxide (As2O3). Primary cell culture (peripheral blood mononuclear cells) and a continuous cell line (MT4) were treated with succussed and unsuccussed homoeopathic potencies, 6CH, 30CH and 200CH. This study aimed to verify the homoeopathic law of similars and to determine whether potencies diluted beyond Avogadro’s constant had physiological effects on cells; whether various potencies would cause different effects as proposed by the Arndt-Schultz law; whether succussed and unsuccussed homoeopathic potencies had different effects on the cells; and to establish whether a biotechnological method could be used to evaluate the above. Initial experiments involved isolation and culturing of the peripheral blood mononuclear cells (PBMCs) and the MT4 cell line. Cell titres were determined using the trypan blue dye exclusion assay. The solubilization method of As2O3 was optimized through various dissolution experiments, so as to attain a homogenous arsenical solution. The MTT assay was used to measure the percentage cytotoxicity and the half maximal inhibitory concentration (IC50) caused by the antagonist As2O3 on the PBMCs and the MT4 cell line. The two cell cultures were compared with regard to their susceptibility to As2O3 and their reliability of response. The homoeopathic potencies of Arsenicum album (6CH, 30CH and 200CH) were prepared by initially triturating the As2O3, and then either hand succussing 10 times (succussed) or allowing to diffuse for 30 s (unsuccussed) in sterile distilled water, with the final potencies made up in cell culture media, RPMI. The MTT assay was used to determine the percentage cell viability when the As2O3-antagonised cells were treated with the Arsenicum album potencies. All assays were performed in triplicate. v The As2O3 was found to fully dissolve when 396 mg of dry As2O3 was added to 100 mL of sterile distilled Milli-Q water, which was left to stand for 10 days at 80°C. The cytotoxicity results showed that the PBMCs were not as reliable as the MT4 cells, which showed significant susceptibility to the As2O3. The IC50 of As2O3 on 1 mL of MT4 cells was found to be 5 μM As2O3 (133 μL) for 48 h. The trypan blue dye exclusion assay demonstrated that the viable MT4 cells decreased in number after exposure to the As2O3, with an increase in number of the non-viable cells. Microscopically, the cells were fewer in number and displayed signs of possible blebbing and cell shrinkage, showing potential cell death due to apoptosis. The cell viability results showed that the Arsenicum album 6CH resulted in the lowest absorbance readings and the Arsenicum album 200CH gave the highest readings; this verified the therapeutic effects of homoeopathic remedies when given according to the law of similars; that potencies diluted beyond Avogadro’s constant had stimulating effects; and that the more dilute potencies stimulated recovery in the cells more than the lower potencies, verifying the Arndt-Schultz law. The treatments and the times of exposure were found to be statistically significant determinants of cell viability, whereas succussion did not cause any significant variation in the results. The study thereby provided evidence that a biotechnological method could be used to scientifically evaluate the physiological effects of homoeopathic potencies on human cells; that the homoeopathic potencies did have therapeutic effects; and that succussion was not required in the potentization method in order to produce a curative remedy.

Fluid-tight obturation of the root canal space is an important requirement for successful root canal treatment. Gutta percha, used as a core material in combination with different sealers, is the most commonly used root filling material and is considered the gold standard. However, it does not possess all the properties of the ideal obturation material. Mineral trioxide aggregate (MTA) is a cement material based on calcium silicates (CSC). It sets by hydration, provides excellent sealing ability, is biocompatible/bioactive and has performed successfully in different clinical applications. The use of MTA as an orthograde obturation material has been proposed. However, MTA is difficult to handle and very little is known about the most appropriate technique to ensure good compaction within the shaped root canal. This research aims to investigate the performance of MTA when used as an orthograde obturation material. The effect of different times of ultrasonic activation of unset material on the incidence of voids in root canals was investigated. Manual compaction of MTA using hand pluggers without ultrasonic activation resulted in minimal void formation. Ultrasonic activation resulted in significantly higher incidence of voids. The removal of the smear layer prior to obturation with MTA resulted in a significantly reduced push-out bond strength between the MTA and radicular dentine. The apical sealing ability of MTA orthograde filling was assessed in comparison with gutta percha and sealer using a dye leakage model. It was concluded that MTA provides a better apical seal against dye penetration over a 30-day observation period. The ability of MTA to reinforce the remaining root structure in comparison with gutta percha and sealer was investigated. MTA significantly increased the resistance to vertical root fracture after one month of storage in synthetic tissue fluid. The radiopacity of MTA together with new calcium silicate cements was assessed and it was concluded that MTA was more radiopaque than gutta percha but less radiopaque than AH-plus sealer. The use of MTA as an orthograde obturation material has shown some potential of enhanced clinical performance in comparison with gutta percha and sealer in terms of sealing ability and bioactivity. However, there are certain disadvantages for obturation with this category of materials in its present form. It is important to point out that MTA is still in its early stages of development. With further improvements to its physical properties, MTA can present a valuable option for obturation of the root canal space.

abstract: ABSTRACT Programmable metallization cell (PMC) technology uses the mechanism of metal ion transport in solid electrolytes and electrochemical redox reactions to form metallic electrodeposits. When a positive bias is applied from anode to cathode, atoms at the anode are oxidized to ions and dissolve in the solid electrolyte. They travel to the cathode under the influence of an electric field, where they are reduced to form electrodeposits. These electrodeposits are filamentary in nature and grow in different patterns. Devices that make use of the principle of filament growth have applications in memory, RF switching, and hardware security. The solid electrolyte under investigation is tungsten trioxide with copper deposited on top. For a standard PMC, these layers are heated in a convection oven to dope the electrolyte. Once the heating process is completed, electrodes are deposited on top of the electrolyte and biased to grow the filaments. What is investigated is the rate of dendritic growth to applied field on the PMC and the composition of the electrolyte. Also investigated are modified three-terminal PMC capacitance change devices. These devices have a buried sensing electrode that senses the increasing capacitance as the filaments grow and increase the upper electrode area. The rate of dendritic growth in the tungsten trioxide and copper electrolyte of different chemistries and applied field to the PMC devices is the important parameter. The rate of dendritic growth is related to the change of capacitance. Through sensing the change in capacitance over time the modified PMC device will function as an odometer device that can be attached to chips. The attachment of these devices to chips, help in preventing illegal recycling of old chips by marking those chips as old. This will prevent would-be attackers from inserting modified chips in systems that will enable them to by-pass any software security precautions. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2019

[Truncated abstract] New, double-doped, Bi2O3-based materials in the Bi2O3 Ln2O3 PbO (Ln = La, Nd, Er and Yb) and Bi2O3 WO3 PbO systems were prepared using solid-state reactions. For the Bi2O3 Er2O3 PbO and Bi2O3 Yb2O3 PbO systems, the air-quenchable compositional domain of the fcc fluorite-type phase was partially established. Temperature dependent conductivity measurements were performed on these quenched-in fluorite-type materials using AC impedance spectroscopy. Conductivity at 750[degrees Celsius] generally increased with increasing Pb2+/Ln3+ and decreasing (Ln3++Pb2+)/Bi3+ ratios. The material (BiO1.5)0.70(ErO1.5)0.15(PbO)0.15 had a conductivity of 0.66 [plus-minus] 0.05 S cm-1 at 750[degrees Celsius], placing it among the most highly conductive Bi2O3-based materials, and was the best new fluorite-type material from a combined conductivity and structural stability viewpoint. Some of the new materials in the Bi2O3 La2O3 PbO and Bi2O3 Nd2O3 PbO systems appeared to have the quenched-in fluorite type structure based on powder X-ray diffraction data. These materials had very high conductivities at 750[degrees Celsius] of `~ 1 S cm-1, but underwent rapid symmetry lowering transformations during heating, thus making them unsuitable for use as solid electrolytes. The fluorite-type structure was not air-quenchable in the Bi2O3 WO3 PbO system, for the compositions synthesised. Room temperature neutron powder diffraction data were collected for quenched-in fluorite-type materials in the (BiO1.5)0.80(LnO1.5)0.20-x(PbO)x, Ln = Er and Yb, x = 0, 0.03, 0.06 and 0.09, and (BiO1.5)0.97-y(ErO1.5)y(PbO)0.03, y = 0.27, 0.17 and 0.12, series. ... This suggests that Pb2+ dopant cations occupy face-centre positions in the fcc unit cell, and the Pb2+ lone pair electrons are likely to be orientated towards an oxide ion vacancy in an adjacent tetrahedral site. Pb2+/oxide ion vacancy interactions affect the migration of oxide ions/oxide ion vacancies through the structure, and are responsible for the significantly larger activation energy for oxide ion migration in the Pb2+-doped materials relative to the Pb2+-free materials. For example, the activation energies of (BiO1.5)0.80(ErO1.5)0.20-x(PbO)x, x = 0.03 and 0.06, were 1.50 [plus-minus] 0.02 and 1.54 [plus-minus] 0.02 eV, respectively, while the activation energy for (BiO1.5)0.80(ErO1.5)0.20 was 1.25 [plus-minus] 0.04 eV. Long-term annealing of the quenched in fluorite-type materials in the Bi2O3 Er2O3 PbO and Bi2O3 Yb2O3 PbO systems at 500 and 600[degrees Celsius] resulted in conductivity lowering structural transformations, making these materials unsuitable for practical use as solid electrolytes at these temperatures. For example, the materials (BiO1.5)0.80(ErO1.5)0.20-x(PbO)x, x = 0.03, 0.06 and 0.09, underwent a fluorite-type to tetragonal transformation during annealing at 500[degrees Celsius] due to <100> oxide ion vacancy ordering, and the rate of conductivity decay at 500[degrees Celsius] increased with increasing Pb2+/Er3+ ratio. Long-term annealing experiments at 500[degrees Celsius] performed on air quenched (Bi2O3)0.705(Er2O3)0.245(WO3)0.050 showed that the disordered fluorite-type structure of this material was not fully stabilised, as evidenced by the presence of superlattice reflections in selected area electron diffraction patterns for the material annealed for 2000 hours, and a gradual conductivity decay after ~ 150 hours annealing.

L'étude d'une batterie optique flexible, capable de moduler sa réflexion dans l'infrarouge et basée sur la technologie PLiON, est présentée dans cette thèse. Dans une première partie, une étude du trioxyde de tungstène monohydraté en fonction de la morphologie du matériau a permis de comprendre et d'améliorer les performances. Le contraste observé sur un film de WO3.H2O est de 40 % (8-12 µm). Une deuxième partie du document analyse le choix de matériaux actifs pour obtenir un contraste important. En fonction du type de matériaux (métal ou semi-conducteur), l'influence de la nature, de la morphologie et de leur structure sur leurs propriétés optiques est soulignée. Dans la dernière partie, nous avons montré que le temps de commutation pouvait être amélioré en utilisant une contre-électrode rapide, en réduisant l'épaisseur des films électroactifs et en remplaçant les ions lithium par des protons. Deux batteries fonctionnant en milieux protonés sont proposées.

This thesis concerns experimental studies of nanocrystalline tungsten trioxide thin films. Functional properties of WO3 have interesting applications in research areas connected to energy efficiency and green nanotechnology. The studies in this thesis are focused on characterization of fundamental electronic and optical properties in the semiconducting transition metal oxide WO3. The thesis includes also applied studies of photocatalytic and photoelectrochemical properties of the material.     All nanocrystalline WO3 thin films were prepared using DC magnetron sputtering. It was found that structures like hexagonal and triclinic phase with different properties can be produced with sputtering technique. Thin film deposition has been performed using different process parameters with emphasis on sputter pressure and films that mainly consist of monoclinic γ-phase, with small contributions of ε-phase. Changes in the pressure are shown to affect the number of oxygen vacancies in the WO3 thin film, with close to stoichiometric WO3 formed at high pressures (30 mTorr), and slightly sub-stochiometric WO3-x, x = 0.005 at lower pressures (10 mTorr). Both stoichiometric and sub-stoichiometric thin films have been characterized by several structural, optical and electronic techniques.    The electronic structure and especially band gap states have been explored and optical properties of WO3 and WO3-x have been studied in detail. The band gap has been determined to be in the range 2.7-2.9 eV. Absorption due to polaron absorption (W5+  -W6+), oxygen vacancy sites (Vo -W6+), and due to differently charged oxygen vacancy states in the band gap have been determined by spectrophotometry and photoluminescence spectroscopy, in good agreement with resonant inelastic x-ray spectroscopy and theoretical calculations. The density of electronic states in the band gap was determined from cyclic voltammetry measurements, which correlate with O vacancy concentration as compared with near infrared absorption.      By combining different experimental methods a thorough characterization of the band gap states have been possible and this opens up the opportunity to tailor the WO3 functionalities. WO3 has been shown to be visible active photocatalyst, and a promising electrode material as inferred from photo-oxidation and water splitting measurements, respectively. Links between device performance in photoelectrochemical experiments, charge transport and the electronic structure have been elucidated.

Pasaulyje neslopsta susidomėjimas fotokataliziniais procesais, kuriuos siekiama pritaikyti vandens skaidymo į vandenilį ir deguonį, organinių ar neorganinių junginių nukenksminimo technologijose. Fotoelektrocheminis vandens skaidymas į elementus vertinamas kaip vienas perspektyviausių būdų, galinčių ateityje užtikrinti efektyvų atsinaujinančių energijos šaltinių panaudojimą. Kuriant fotokatalizines sistemas, nanostruktūrinis titano dioksidas (TiO2) išlieka viena tinkamiausių ir labiausiai tyrinėtų medžiagų. Tačiau titano dioksidas neaktyvus regimosios spinduliuotės srityje, todėl alternatyva TiO2 fotokatalizatoriui gali būti kitas n-tipo puslaidininkis – volframo trioksidas (WO3). Volframo trioksidui yra būdingos fotochrominės savybės, jis absorbuoja dalį regimosios spinduliuotės. Daugelio tyrėjų nuomone, norint padidinti jo fotokatalizinį aktyvumą, tikslinga kurti mišrius oksidinius katalizatorius arba modifikuoti paviršių kitomis medžiagomis. Atsižvelgiant į literatūroje pateiktus duomenis, šiame darbe buvo siekiama pagaminti aktyvius kompozitinius fotokatalizatorius, kurių pagrindinė sudedamoji dalis yra volframo trioksidas. Darbas skirtas naujų medžiagų, kurios galėtų būti naudojamos fotokataliziniuose ir fotoelektrocheminiuose procesuose, paieškai ir charakterizavimui. Šio darbo tikslas – susintetinti TiO2, Se ir Co–P priedais modifikuotus volframo trioksido katalizatorius, ištirti jų struktūrą, fotokatalizines bei fotoelektrochemines savybes. / Scientific community exhibits a great interest in photocatalytic processes such as water photosplitting or photooxidation of organic substances. The photoelectrochemical splitting of water into hydrogen and oxygen is considered as the very promising pathway in the development of a long-term, sustainable energy economy. Titania (TiO2) still remains to be the most suitable for practical applications. However, using it as a photocatalyst still has some major issues: due to the fast recombination of photogenerated charge carriers, the overall quantum efficiency is relatively low, and titania is mostly sensitive to UV irradiation. Tungsten trioxide (WO3) is another semiconductor which can be employed in photocatalysis. Besides its photochromic properties, it has a smaller band gap than titania and may be activated under visible light illumination. In order to improve the photocatalytic efficiency it may be reasonable enough to combine both titania and tungsten trioxide into one photocatalyst or to modify their surface with various compounds. This work is relevant in the search of new materials suitable for photocatalytic and photoelectrocatalytic processes. The main object of this work was to synthesize active tungsten oxide-based composite catalysts and evaluate their structure and properties. Aim of the work was to synthesize WO3 catalysts modified with TiO2, Se and Co-P additives, to investigate their structure, photocatalytic and photoelectrochemical properties.