Nanoszerkezetű fotokatalizátorok = Nanostructured photocatalysts

A pályázat keretében tanulmányoztuk a nanoszerkezetű titán-dioxid ill. titano-szilikát alapú katalizátorok előállítási lehetőségeit, fizikai-kémiai tulajdonságait és megteremtettük a fotokatalitikus tesztelésükhöz szükséges modellreakció infrastruktúráját. Három anyagcsoport fotokatalitikus tulajdonságait vizsgáltunk 2,4,6-triklór-fenol lebontásában. Egyrészt mezopórusos MCM-41 vagy SBA-15 titánnal izomorfan szubsztituált, vagy TiO2-al impregnált változataival, másrészt réteges szerkezetű szilikátokon (laponit. magadiit) immobilizált titán-dioxid (anatáz) nanoszemcsékkel valamint nitrogénnel dopolt nanocső szerkezetű titán-dioxidokkal (anatáz) végeztünk fotokatalitikus kísérleteket. Vizsgálataink bizonyították, hogy a titán-dioxiddal módosított Laponit katalizátorok ígéretes anyagok toxikus szennyezők lebontásában gyakorlati szempontból is, mivel előállításuk nem túl költséges és nanoméretű titán-dioxid szemcséket olyan formában képesek immobilizálni, hogy elválasztásuk a szennyvizekből könnyen kivitelezhető. A nitrogénnel dopolt titán-nanocsövek a fény látható tartományban is gerjeszthető, aktív fotokatalizátoroknak bizonyultak. | Synthesis methods and phisical-chemical properties of nanostructured titania or titania-silica materials were studied and the infrastructure of the reaction for their photocatalytic testing was established. Photocatalytical degradation of 2,4,6-trichlorophenol was investigated on three types of titania based nanostructured materials. These were: (i) MCM-41 or SBA-15 based materials isomorphously substituted by titanium or impregnated by TiO2, (ii) titania (anatase) nanoparticles immobilized on layered silicates (Laponite, magadiite) and (iii) N-doped nanotube structered anatase titania materials. Our investigations evidenced titania modified laponite catalysts are promising materials for the degradation of toxic pollutant in water in practice, because their production is not expensive and they can immobilze titania nanocrystals in such form that enables the separation from wastewaters easily. Application of N-doped nanotube structured titania materials can enhance the photocatalytic activity to the visible range

Impact of silica structure of copper and iron-containing SBA-15 and SBA-16 materials on toluene oxidation

Copper and iron modified SBA-15 and SBA-16 materials were prepared by incipient wetness impregnation technique and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 physisorption, temperature-programmed reduction (TPR-TGA), UV-Vis diffuse reflectance and Mössbauer spectroscopy. Formation of finely dispersed copper and iron-oxide species was observed on both supports, whereas copper ferrite could be evidenced only on SBA-15. It was found that the structural and surface properties of the mesoporous supports determine the type of formed metal oxides, their dispersion, reducibility and the catalytic activity in total oxidation of toluene. On SBA-16 support penetration of metal salt into the bimodal channel system is hindered therefore separate copper- and iron-oxide phases are formed on the outer surface of catalysts. The catalytic activity and stability are lower due to the easier agglomeration of particles. On SBA-15 support finely dispersed metal-oxides can be found in the mesoporous channels. Their interaction is favored to form bimetallic phases enhancing the catalytic activity and stability in total oxidation of toluene

Glycerol acetylation on mesoporous KIL-2 supported sulphated zirconia catalysts

Zirconia nanomaterials were prepared by impregnation of KIL-2 type silica with 4, 8 and 12 wt.% ZrO2 and were modified by sulphate groups in order to vary the type and strength of acidity. Samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and N2 physisorption methods. Acidic properties of adsorbed pyridine were investigated by FT-IR spectroscopy. The catalytic performance of ZrKIL-2 and SO4 2−/ZrKIL-2 in glycerol esterification with acetic acid was studied and compared to that of pure zirconia varieties. It was found that silica-supported zirconia samples are more active than pure zirconia ones. With increasing ZrO2 content, KIL-2-supported catalysts showed increasing catalytic activity and selectivity in producing valuable fuel additives, di- and triacetyl glycerols. Sulphated analogues showed even higher activity and selectivity compared to non-sulphated ones due to their strong Brönsted acidity

Rétegszilikátok átkristályosítása zeolitokká, valamint réteges szerkezetű zeolit prekurzorokból mikro- és mezopórusos fémszilikátok előállítása = Recrystallisation of layered silicates into zeolites and preparation of micro- and mesoporous silicates from layered zeolite precursors

Egyfajta rétegszilikát, a magadiit szilárd-fázisú átkristályosításával alumínium és bórtartalmú beta zeolitokat állítottunk elő. A bór nem befolyásolta a zeolit vázszerkezetében a Si(OH)Al(OSi)3 helyekkel kapcsolatban levő Brönsted savas centrumok saverősségét. A bór beépítése gyengén savas centrumokat hoz létre, melyek részt vesznek az ioncsere folyamatokban. Az [Al,B]-BEA zeolitokban az erősen savas Brönsted centrumok számát a rétegszilikát alumínium-tartalmával szabályozhatjuk. A Ni/[Al,B]-BEA zeolitok az alkánok hidrokonverziójában kevésbé aktív katalizátorok mint a Ni/[Al]-BEA, azonban a bór beépítése az izomerizációs szelektivitás jelentős növekedését eredményezte. A zeolitok katalitikus tulajdonságaiban mutatkozó különbségek a kémiai összetételtől függő adszorpciós tulajdonságokban jelentkező eltéréssel magyarázhatók. Nanokristályos, mikropórusos MCM-22 zeolitból és mezopórusos MCM-41 szilikátból álló kompozitokat állítottunk elő. A kompozitok nagy fajlagos felületűek és nagyobb hidrotermális stabilitást mutatnak mint a tiszta MCM-41. Erős (NH3, piridin) és gyengén bázikus (N2) adszoptívumokkal tesztelve igazoltuk, hogy a [Fe]-MCM-22 gyengébb saverősségű szerkezeti hidroxil-csoportokat tartalmaz mint az [Al]-MCM-22. A ferriszilikátban a vas koordinációs állapotát és redoxi viselkedését Mössbauer spektroszkópiával tanulmányoztuk. Összefüggést állapítottunk meg a H-[Fe]-MCM-22 savassága és a vas állapota között. | Beta zeolites, containing aluminum and boron were prepared by solid-state recrystallization of the layer silicate magadiite. Effect of framework boron on the acid strength of hydroxyls, associated with (Si(OH)Al(OSi)3 sites, could not be evidenced. However, the incorporated boron was shown to give rise to weak acid sites, which are involved in ion-exchange processes. The number of strong Brønsted sites can be controlled by the Al content of the layer silicate. The nickel loaded [Al,B]-BEA zeolites proved to be less active catalysts for the hydroconversion of alkanes, than the [Al]-BEA. The incorporation of boron resulted in a considerable selectivity shift towards isomerization. The different catalytic activities of the boron and aluminum-containing beta zeolites were ascribed to composition dependent adsorption properties of the samples. Micro/mesoporous aluminosilicate composite, comprising nanosize randomly orientated stacks of thin layers of MCM-22 zeolite and MCM-41 silicate was prepared. The composite has high surface area and shows higher hydrothermal stability than the pure MCM-41. The acid strength of bridged hydroxyls in [Fe]-MCM-22 tested by strong (NH3, pyridine) and weak base (N2) adsorptives was found to be weaker than the strength of the bridged hydroxyls in [Al]-MCM-22. The coordination state and redox behavior of iron were studied by Mössbauer spectroscopy. A relationship between the acidity of [Fe]-MCM-22 and the state of iron was ascertained

Harántcsíkolt izom SR kalcium csatornájának modulációja egészséges és kóros körülmények között = Modulation of the SR calcium channels of striated muscle in health and disease

Az izom összehúzódás kiváltásában centrális szerepet játszó elektromechanikai csatolás kulcs-molekuláit tanulmányoztuk. Megállapítottuk, hogy a gadolinium ion mind a cisz mind a transz oldalról hasonlóan gátolja a csatornát (Ki=5,38+-0,63microM és Ki=5,72+-0,84microM, Ncis=4,21+-0,47, Ntrans=4,5+-0,41), feltehetően a kötőhely a csatorna vezető pórusának belsejében található, és a két oldal felől egyformán érhető el. Az európium a cis oldalról kvalitatíve hasonló módon gátol (Ki=107+-17nM), míg trans oldalról hatástalan. Megállapítottuk, hogy a timol gátolja a kalcium pumpát (K i=253+-4,7 microM, NHill=1,62+-0,05) és a csatorna aktiválásával gyors kalcium felszabadulást vált ki (Vmax=0,47+-0,04 nmol/s, EC50=258+-21 nM, NHill=3,0+-0,54). Szintetizáltuk a DHP receptor adott szakaszait, és megállapítottuk, hogy a maurocalcin (MCa) két módon is hat a RyR1 kapuzására, "hosszú fél-nyitott" (LLSS) állapotokat indukál, és az LLSS időszakok között növeli a csatorna nyitvatartási valószínűségét. A toxin pontmutánsai segítségével kimutattuk, hogy a 31 aminosavból álló teljes szekvenciának a hatás szempontjából legkritikusabb tagja a 24-es aminosav. A toxinmolekulát a 23, 22 20 és 8-as pozícióban alaninra mutálva a hatás erőssége attól függött, hogy térbelileg milyen messzire van a mutációs pont a kritikus 24-es pozíciótól. A MCa hatása polaritás- és potenciálfüggő | Key molecules playing central role on the muscle contraction have been studied. We have shown using bilayer technique that Gadolinium inhibits the calcium channel from both sides (Ki=5.38+-0.63microM and Ki=5.72+-0.84 microM, Ncis=4.21.+-0.47, Ntrans=4.5+-0.41) showing, that the Gd3+ binding site is located in the middle region of the channel pore equally accessible from both sides while Eu3+ inhibited the channel only from the cis side (Ki=107+-17nM). We have shown, that thymol inhibits the SR calcium pump (K i=253+-4.7 microM and NHill=1.62+-0.05) and evokes calcium release (Vmax=0.47+-0.04 nmol/s, EC50=258+-21 nM, NHill=3.0+-0.54). The effect of thymol on RyR1 and RyR2 is similar. Analogous sequence to the different segments of the II-III loop of the DHPR were synthesized followed by the demonstration that maurocalcin (MCa) alters the gating of the RyR1 and RyR2. It induces long lasting subconductance events (LLSS) which might last even for several seconds, and it increases the open probability between the LLSS events too. Using different point mutations of the 31 residue peptide it was shown, that the position 24 is critical for the toxin effect. Alanine mutations in the position of 8, 9, 20, 22, 23 resulted partial LLSS effect according to the three dimensional distance of the given amino acid from the crucial 24 residue. The MCa effect found to be strongly polarity and slightly potential dependent

Solid-state encapsulation of Ag and sulfadiazine on zeolite Y carrier

Hypothesis: A new simplified procedure for encapsulation of antibacterial silver nanoparticles by Solid-state Ion Exchange (SSIE) procedure over zeolite Y, followed by deposition of sulfadiazine (SD) by dry mixing was examined for the preparation of topical antibacterial formulations. The ion-exchange and adsorptive properties of the zeolite matrix were utilized for the bactericidal Ag deposition and loading of antibiotic sulfadiazine. Experiments: Assessment of the encapsulation efficiency of both active components loaded by solid and liquid deposition methods was made by X-ray diffraction, TEM, FT-IR spectroscopy and thermogravimetric analysis (TGA). SD release kinetics was also determined. Findings: Sustained delivery of sulfadiazine has been observed from the Ag-modified zeolites compared to the parent HY material. It was found that if SD was loaded in solution, part of the zeolite silver ions was released and interacted with SD, forming AgSD. By solid-state SD deposition, the reaction between the drug and the silver was restricted within the limits of inter-atomic interaction, and total but prolonged drug release occurred. © 2015 Published by Elsevier Inc

Steroid concentrations in atopic dermatitis patients: Reduced plasma DHEAS and increased cortisone levels.

Atopic dermatitis (AD) is a chronically relapsing inflammatory skin disease, which is characterized by a disrupted epidermal barrier function present both in affected skin and in non-affected skin. Mainly glucocorticosteroids were used in topical and systemic atopy treatments because of their potent anti-inflammatory effects, unfortunately with strong side effects. In this study we determined that 2 out of 16 steroids were significantly different in healthy volunteers vs AD-patients. Cortisone, which is higher in AD-patients plasma, is a direct precursor of the bioactive corticosteroid cortisol, which just displays a higher tendency and is known for its potent anti-inflammatory effects. In addition a tendency of reduced levels of the anti-inflammatory ER ligand estrone was found in AD-patients. DHEA is a precursor of testosterone, its levels just display a lower tendency in male AD-patients, while its sulfonation metabolite DHEAS is lower in male and female AD-patients. We found and conclude that altered steroid levels in the plasma of AD-patients indicate altered vitamin D signaling (based on reduced DHEA sulfonation) and increased feedback for anti-inflammatory signaling (increased levels of cortisone) present in AD-patients. This article is protected by copyright. All rights reserved

Silver- and sulfadiazine-loaded nanostructured silica materials as potential replacement of silver sulfadiazine

Silver sulfadiazine (AgSD) is the leading topical antibacterial agent for the treatment of burn wound infections. Antibacterial effect of AgSD is limited by its poor aqueous solubility, and antibacterial activity develops only by decomposition of AgSD to silver ions and sulfadiazine. In this study, it is for the first time that application of silver-modified nanoporous silica carriers (MCM-41 or SBA-15) loaded with sulfadiazine (SD), instead of silver sulfadiazine, overcoming the abovementioned disadvantages has been demonstrated. By direct or post synthesis methods, 5–15 nm sized silver nanoparticles can be stabilized in the channels or on the outer surface of nanoporous silica supports; moreover, the empty channels can be loaded by SD molecules. The SD-loaded, silver-modified materials show sustained release properties and similar or even better antimicrobial properties than AgSD. Adsorption of AgSD on nanoporous silica particles significantly improves its water solubility