Les voies métaboliques les plus importantes dans le contrôle du stress oxydant chez la plante restent à élucider. Celles liées au glutathion jouent un rôle important. Cependant, les réactions responsables de l'oxydation du glutathion (du GSH en GSSG) n'ont pas encore été clairement identifiées. L’analyse des données biochimiques, transcriptomiques et génétiques soulèvent des questions pour mieux comprendre comment la régulation redox liée au stress pourrait influer sur la signalisation hormonale chez les plantes. Par une approche de génétique inverse utilisant, notamment, le mutant photorespiratoire conditionnel cat2, nous avons étudié la réponse et l'importance fonctionnelle de trois voies potentielles, médiées par les glutathion S-transférases, les peroxirédoxines dépendant de la glutarédoxine et les déhydroascorbate réductases (DHARs) chez Arabidopsis. Ainsi, l'interaction entre les DHARs semble être nécessaire pour coupler les pools d'ascorbate et de glutathion lors d’un stress oxydant. En complément à l'approche expérimentale, une modélisation mécaniste a permis d'étudier la production de H2O2 et son métabolisme, en lien avec l'activité catalase et la voie ascorbate-glutathion. Le modèle révèle que la catalase et l'ascorbate peroxydase prennent en charge de concert le traitement de H2O2, y compris dans les conditions optimales de croissance. Nos simulations suggèrent que la disponibilité en NADPH peut déterminer l'oxydation du glutathion via la monodéshydroascorbate réductase. Nos résultats expérimentaux et le modèle cinétique valident que la sensibilité du statut du glutathion au stress oxydant constitue un senseur approprié des augmentations du H2O2. / The most important metabolic pathways in the control of oxidative stress remain to be elucidated in plants. Those linked to glutathione play an important role. However, the reactions responsible for its oxidation have not been clearly identified. Here, analysis based on available biochemical, transcriptomic and genetic data emphasized likely important questions to be elucidated for a full understanding of how stress-related redox regulation might impinge on phytohormone-related signaling pathways. Using a reverse genetics approach and the photorespiratory conditional cat2 mutant, we studied the response and functional importance of three potential routes for glutathione oxidation pathways mediated by glutathione S-transferases, glutaredoxin dependent peroxiredoxins, and dehydroascorbate reductases (DHAR) in Arabidopsis during oxidative stress. Hence, interplay between different DHARs appears to be necessary to couple ascorbate and glutathione pools and to allow glutathione-related signaling during enhanced H2O2 metabolism. In addition to experimental work, modelling is another way to investigate H2O2 production and its metabolism related to catalase activity and ascorbate glutathione pathway. This approach led to major conclusions, that catalase and ascorbate peroxidase can share the load in H2O2 processing even in optimal growth conditions. Furthermore, simulations propose that NADPH availability may determine glutathione oxidation through its influence on monodehydroascorbate reduction. Taken together, experimental results and our kinetic model strengthen that the sensitivity of glutathione status to oxidative stress acts as a suitable sensor of increased H2O2.

The initial purpose of this work was to investigate the interaction of methylmercuric chloride (MMC) and X-irradiation given as a co-insult upon the rat blood-brain barrier (BBB). The indicators used to determine BBB alterations were mortality and the in vivo tissue uptake of radioactive sulfate administered as 3 5S-sodium sulfate. The results of the interaction studies indicated a neutralization of effects when MMC and X-irradiation were given together. X-irradiation as a single insult generally caused an increase in sulfate uptake by the brain regions monitored, whereas MC treatment generally resulted in decreased sulfate uptake. The neutralization patterns following co-insult treatments were somewhat varied in the different brain regions, exhibiting cancellation of effects in some cases and overriding by one insult in other eases. From the data obtained by this work and in the literature, it is hypothesized that the P-L organelle system of the perivascular glia serves as a trap for MMC, preventing MMC from reaching the neurons. The system appears to proliferate in response to increased peroxides in the body fluids, thereby increasing tolerance to larger doses of MMC.

Human neutrophil 5-lipoxygenase (5-LOX) oxidizes arachidonic acid (AA) to 5S-hydro(pero)xy-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-H(p)ETE) and leukotriene (LT)A4, which is further converted to the chemoattractant LTB4. These cells contain also the heme enzyme myeloperoxidase (MPO) producing several potent oxidants such as hypochlorous acid (HOCl). Previously, it was shown that MPO-metabolites influence 5-LOX product formation. Here, we addressed the question, whether a simultaneous activation of MPO and 5-LOX in neutrophils results in comparable changes of 5-LOX activity. Human neutrophils were stimulated with H2O2 or phorbol 12-myristate 13-acetate (PMA) for MPO activation and subsequently treated with calcium ionophore A23187 inducing 5-LOX product formation on endogenous AA. Special attention was drawn to neutrophil vitality, formation of MPO-derived metabolites and redox status. The pre-stimulation with H2O2 resulted in a concentration-dependent increase in the ratio of 5-HETE to the sum of LTB4 + 6-trans-LTB4 in consequence of MPO activation. Thereby no impairment of cell vitality and only a slightly reduction of total glutathione level was observed. An influence of MPO on 5-LOX product formation could be suggested using an MPO inhibitor. In contrast, the pre-stimulation with PMA resulted in different changes of 5-LOX product formation leading to a reduced amount of 5-HETE unaffected by MPO inhibition. Furthermore, impaired cell vitality and diminished redox status was detected after PMA stimulation. Nevertheless, a MPO-induced diminution of LTB4 was obvious. Further work is necessary to define the type of 5-LOX modification and investigate the effect of physiological MPO activators.

<p>Dugoročno re&scaron;enje problema povećanog ukupnog kapaciteta vodenih ekosistema, posledičnog ubraznja eutrofizacije i cvetanja potencijalno toksičnih cijanobakterija podrazumeva smanjenje priliva nutrijenata, kao i eliminaciju vi&scaron;ka nutrijenata iz samog vodenog ekosistema, naročito azota i fosfora. Kao re&scaron;enje ovog&nbsp; problema&nbsp; se&nbsp; predlaže&nbsp; istovremena&nbsp; upotreba&nbsp; seta&nbsp; poznatih&nbsp; alternativnih&nbsp; metoda,&nbsp; označenih zajedničkim&nbsp; nazivom&nbsp; ekomanipulacija,&nbsp; koji&nbsp; uključuje:&nbsp; mehaničko&nbsp; uklanjanje&nbsp; makrofita&nbsp; i&nbsp; biomase cijanobakterija, upotreba plutajućih ostrva, masovno izlovljavanje ribe.<br />Izvr&scaron;ena&nbsp; je&nbsp; procena&nbsp; mehaničkog&nbsp; uklanjanja&nbsp; trske&nbsp; (Phragmites&nbsp; australis)&nbsp; u&nbsp; kontekstu&nbsp; za&scaron;tite&nbsp; i preči&scaron;ćavanja vodenih ekosistema i kao energetskog resursa na teritoriji Vojvodine. Procenjeno je da je oko 0,98% povr&scaron;ine Vojvodine pokriveno trskom sa prosečnim prinosom od oko 2 kg/m 2 , odnosno oko 20 t/ha. Ko&scaron;enjem i uklanjanjem nadzemne biomase bi moglo da se ukloni do 333,20 kg/ha azota i 25,20<br />kg/ha&nbsp; fosfora.&nbsp; Pored&nbsp; povoljnih&nbsp; karakteristika&nbsp; trske&nbsp; kao&nbsp; energetske&nbsp; sirovine,&nbsp; tro&scaron;kovi&nbsp; obrade&nbsp; biomase trenutno prevazilaze potencijalnu zaradu, zbog čega ova makrofita ima veći značaj na lokalnom nivou. Ispitivana&nbsp; je&nbsp; efikasnost&nbsp; usvajanja&nbsp; nutrijenata direktno&nbsp; iz&nbsp; vodenog&nbsp; stuba putem&nbsp; uklanjanja&nbsp; nadzemne biomase trske iz PPES jedinica, kao i testiranje održivosti čitavog PPES sistema. Iako uklanjanje oko<br />800&nbsp; g&nbsp; nadzemne&nbsp; biomase&nbsp; trske&nbsp; može&nbsp; smanjiti&nbsp; ukupni&nbsp; kapacit&nbsp; do&nbsp; izvesne&nbsp; mere,&nbsp; dodatne&nbsp; vrednosti upotrebe&nbsp; PPES&nbsp; sistema&nbsp; poput usvajanja&nbsp; toksičnih&nbsp; materija,&nbsp; korisne&nbsp; upotrebe&nbsp; plastičnog&nbsp; otpadnog materijala, proizvodnje biljne biomase ovu metodu čini značajnim delom sistema ekomanipulacija. Kori&scaron;ćenjem&nbsp; puferskog&nbsp; sistema&nbsp; ekoremedijacije&nbsp; baziranog&nbsp; na&nbsp; izno&scaron;enju&nbsp; biomaske&nbsp; trske&nbsp; se&nbsp; takođe<br />obezbeđuje smanjenje ukupnog kapaciteta. Na taj način se može postići kontrola ubrzane eutrofizacije na četiri funkcionalna nivoa u dinamici ekosistema, koji podrazumevaju: sprečavanje priliva materija u vodeni&nbsp; ekosistem&nbsp; iz&nbsp; spolja&scaron;nje&nbsp; sredine&nbsp; izgradnjom&nbsp; mokrih polja,&nbsp; povećanje&nbsp; procesa&nbsp; razgradnje uvođenjem aeracije, preči&scaron;ćavanje mulja ili efluenta i manipulacija trskom u priobalju. Procenjena&nbsp; je&nbsp; efikasnost&nbsp; mehaničkog&nbsp; uklanjanja&nbsp; toksične&nbsp; biomase&nbsp; cijanobakterije&nbsp; vrste Planktothrix rubescens iz&nbsp; akumulacije&nbsp; Vrutci. Rezultati&nbsp; ukazuju&nbsp; na&nbsp; efikasnost&nbsp; ove&nbsp; metode&nbsp; u&nbsp; smanjenju&nbsp; ukupnog kapaciteta,&nbsp; međutim&nbsp; samo&nbsp; tokom&nbsp; perioda&nbsp; cvetanja.&nbsp; Ispitivana&nbsp; je&nbsp; sposobnost&nbsp; 14&nbsp; sojeva&nbsp; bakterija, izolovanih iz sakupljenje povr&scaron;inske skrame P. rubescens, da degradiraju cijanotoksin mikrocistin-LR. Degradacija toksina posle devet dana nije detektovana, &scaron;to je moglo da bude posledica dužeg perioda<br />adaptacije (lag faze) koji je bio potreban da bi se aktivirali odgovarajući geni i enzimski putevi odgovorni za biodegradaciju.<br />Ispitivana je efikasnost metode masovnog izlovljavanja babu&scaron;ke (Carassius gibelio) iz sektora IV jezera Palić. Na osnovu količine iznete biomase tokom probnog izlova 2016. godine i poznatog hemijskog sastava, procenjeno je da je masovnim izlovom moguće ukloniti značajnu količinu nutrijenata na nivou čitavog jezera. Uprkos efikasnosti i pratećim povoljnim promenama u ekosistemu, zbog složenosti lanca ishrane&nbsp; i&nbsp; uop&scaron;te&nbsp; jezerskog&nbsp; ekosistema&nbsp; se&nbsp; preporučuje&nbsp; primena&nbsp; pridruženih&nbsp; metoda&nbsp; biomanipulacije<br />ribljom fondom, kao i drugih metoda ekomanipulacije. Ispitivani su cijanocidni efekti vodonik-peroksida, kao dodatne metode u procesu revitalizacije jezera. Uzorci&nbsp; vode&nbsp; iz&nbsp; srpskih&nbsp; jezera Bečmenska&nbsp; bara (sektor&nbsp; Bečmen&nbsp; 3) i jezera&nbsp; Luda&scaron;&nbsp; i&nbsp; finskog&nbsp; jezera<br />K&ouml;yli&ouml;nj&auml;rvi su bili tretirani različiti koncentrcijama vodonik-peroksida. Analize sadržaja hlorofila a i intracelularnih&nbsp; mikrocistina,&nbsp; indeksa&nbsp; vijabilnosti&nbsp; pokretnih&nbsp; grupa&nbsp; necijanobakterijskog&nbsp; fitoplanktona, zooplanktona i osetljivosti makroinvertebrata, ukazale su na mogućnost efikasne selektivne supresije cijanobakterija ravnomernim apliciranjem 2-5 mg/L vodonik-peroksida. Uočena je različita osetljivost kod ispitivanih grupa organizama na dejstvo agensa, zbog čega je u primeni ove metode neophodan<br />dodatni oprez. Da bi se obezbedio uspe&scaron;an proces revitalizacije jezera, važno je da se metode ekomanipulacije prilagode stanju i karakteristikama jezera, a da se vodonik-peroksid koristi samo u slučaju potrebe. Na takav načinmože&nbsp; nesmetano&nbsp; da&nbsp; se&nbsp; odvija&nbsp; dugotrajan&nbsp; proces&nbsp; revitalizacije.&nbsp; Zbog&nbsp; složenosti&nbsp; problema&nbsp; povećanja ukupnog&nbsp; kapaciteta,&nbsp; ubrzane&nbsp; eutrofizacije&nbsp; i&nbsp; procesa&nbsp; revitalizacije,&nbsp; neophodno&nbsp; je&nbsp; obezbediti multidisciplinarni&nbsp; pristup,&nbsp; pripremu&nbsp; akcionog&nbsp; plana&nbsp; i&nbsp; sprovođenje&nbsp; metoda&nbsp; pod&nbsp; strogo&nbsp; kontrolisanim uslovima.</p> / <p>A long-term solution for the problem of increased total capacity in water ecosystems, and consequently accelerated eutrophication and potentially toxic cyanobacterial blooms, implies the restriction of nutrient inputs to the water bodies, as well as elimination of additional nutrients directly from water ecosystems,especially nitrogen and phosphorus. As a solution for this problem, it is proposed to simultaneously use a &nbsp; set&nbsp; of&nbsp; alternative&nbsp; methods,&nbsp; entitled&nbsp; as&nbsp; ecomanipulation,&nbsp; that&nbsp; include:&nbsp; mechanical &nbsp; removal&nbsp; of macrophytes and cyanobacterial biomass, floating islands, extensive fishing. Mechanical removal of Common reed (Phragmites australis) was estimated for the purpose of protection and&nbsp; purification&nbsp; of&nbsp; water&nbsp; ecosystems,&nbsp; as&nbsp; well&nbsp; as&nbsp; an energy&nbsp; source&nbsp; in&nbsp; the&nbsp; Vojvodina&nbsp; region.&nbsp; It&nbsp; was estimated that about 0,98% of the Vojvodina region is covered with common reed, with an average yield of 2 kg/m2, eg about 20 t/ha. By harvesting and removing of above-ground biomass, it would be possible to&nbsp; remove&nbsp; up&nbsp; to&nbsp; 333.20&nbsp; kg/ha&nbsp; of&nbsp; nitrogen&nbsp; and&nbsp; 25.20&nbsp; kg/ha&nbsp; of&nbsp;&nbsp; phosphorus.&nbsp; Besides&nbsp; favorable characteristics as an energy source, the cost of biomass processing currently exceeds potential revenues, hence this macrophyte is more significant at the local level.&nbsp; The efficiency of nutrient absorption directly from the&nbsp; water column by removal of the reed biomass incorporated in the PPES unites was examined, as well as testing the&nbsp; sustainability of the whole PPES system. Although&nbsp; removal&nbsp; of&nbsp; about&nbsp; 800&nbsp; g&nbsp; of&nbsp; the&nbsp; above-ground&nbsp; reed&nbsp; biomass&nbsp; can&nbsp; decrease&nbsp; the&nbsp; total capacity up to a certain extent, additional values of PPES usage like the uptake of toxic compounds,useful use of plastic waste material, production of plant biomass makes this method important part&nbsp; of ecomanipulation system. The use of a buffer system of ecoremediation based on the removal of reed biomass also provides a reduction in total capacity. In this way,&nbsp; control of accelerated eutrophication can be achieved at four functional levels in ecosystem dynamics, which include: preventing the&nbsp; inflow of matter into the aquatic ecosystem from the external environment by building artificial wetlands, increasing the decomposition process by introducing aeration, sludge or effluent treatment, and reed manipulation in the coastal area. The efficiency of mechanical removal of toxic biomass&nbsp; of cyanobacteria Planktothrix rubescens from the Vrutci reservoir was estimated. The results indicate the effectiveness of this method in reducing the total capacity, but only during the blooming period. The ability of 14 bacterial strains, isolated from collected&nbsp; P. &nbsp; rubescens&nbsp; surface&nbsp; scum,&nbsp; to&nbsp; degrade&nbsp; cyanotoxin&nbsp; microcystin-LR&nbsp; was&nbsp; investigated. Degradation of toxin after nine days was not detected, which could be a consequence of a longer period of&nbsp; adaptation&nbsp; (lag&nbsp; phase)&nbsp; that&nbsp; was&nbsp; needed&nbsp; for&nbsp; activation&nbsp; of&nbsp; certain&nbsp; genes&nbsp; and&nbsp; enzyme&nbsp; pathways responsible for biodegradation. The efficiency of extensive fishing of Prussian carp (Carassius gibelio) from the sector IV of Lake Palić was investigated. Based on the amount of removed biomass during the trial catch in 2016, and the known chemical composition of fish, it was estimated that extensive fishing can remove a significant amount of nutrients at the level of the entire lake. Despite the efficiency and following favorable changes in the ecosystem,&nbsp; due&nbsp; to&nbsp; the&nbsp; complexity&nbsp; of&nbsp; the&nbsp; food&nbsp; chain&nbsp; and&nbsp; the&nbsp; lake&nbsp; ecosystem&nbsp; in&nbsp; general,&nbsp; the&nbsp; use&nbsp; of associated methods of biomanipulation with fish stock, as well as other methods of ecomanipulation, is recommended.<br />The potential of cyanocidal effects of hydrogen peroxide, as an auxiliary method in the&nbsp; process of lake revitalization, was investigated. Water samples from Serbian lakes Bečmenska bara (sector Bečmen 3) and Lake Luda&scaron;, as well as Finnish Lake K&ouml;yli&ouml;nj&auml;rvi, were treated with different concentrations of hydrogen peroxide. Analysis of contents of chlorophyll a and intracellular microcystins, viability index of&nbsp; non-cyanobacterial&nbsp; moving&nbsp; phytoplankton,&nbsp; zooplankton,&nbsp; and&nbsp; sensitivity&nbsp; of&nbsp; macroinvertebrate indicated the possible efficiency of the selective suppression of cyanobacteria by uniform application of 2-5 mg/L of hydrogen peroxide in the water column. Examined groups of organisms expressed different sensitivity towards the applied concentrations of the agent, which is the reason for additional caution in the &nbsp; application of this method.In order to provide successful lake revitalization, it is important to adjust methods of ecomanipulation to the condition and characteristics of the lake, and also to use hydrogen peroxide only when it is necessary.In this way, the long recovery process can proceed smoothly. Due to the complexity of the problem of increased total capacity, accelerated eutrophication, and the process of revitalization, it is necessary to provide a multidisciplinary approach, preparation of an action plan and implementation of methods under strictly controlled conditions.</p>

Title: Study of cerium oxide thin films for biosensing applications Author: Yuliia Kosto Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Vladimír Matolín, DrSc. Abstract: The presented scientific work was conducted in two main directions. The first one is an investigation of the simple biomolecules (glycine and sarcosine) bonding to cerium oxide model films by surface science techniques: photoelectron and near-edge X-ray absorption spectroscopies. Adsorption chemistry and thermal stability of the molecules on the oxides were studied in relation to the oxidation state of ceria cations, film morphology, and molecular deposition method. The oxygen vacancies in the oxide were shown to affect the adsorption geometry of glycine and stimulate molecular decomposition. The polycrystalline oxide morphology provided stabilizing effect on the glycine adlayer. Sarcosine deposited in vacuum formed densely packed adlayer with the molecules directed outwards. Interestingly, the results revealed that molecular film deposited from the aqueous solution, in contrast to deposition in vacuum, induces continuous reduction of the cerium oxide during thermal annealing. The second part is a study of polycrystalline cerium oxide thin films as an electrode for electrochemical and electrochemiluminescent...

Streptococcus pneumoniae (S. pneumoniae) is a Gram-positive, encapsulated bacterium capable of causing significant morbidity and mortality throughout the world. A hallmark of S. pneumoniae infection is infiltration of neutrophils (PMNs) that assist in controlling the spread infection but may also contribute to pathology. Paradoxically, studies have shown that limiting PMN infiltration into the lumen of the lung during infection actually betters clinical outcome in experimental S. pneumoniae infection. The final step in PMN luminal trafficking is a Hepoxilin A3 (HXA3)-dependent migration across the pulmonary epithelium. HXA3 is a PMN chemoattractant that forms gradients along the polarized epithelial face, drawing PMNs from the basolateral to the apical surface during proinflammatory responses. HXA3 requires assistance of an integral- membrane protein transporter to escape the cell and form the gradient. The pulmonary HXA3 transporter is currently unidentified. In this work, we identify the pulmonary HXA3 transporter as the ATP-Binding Cassette Transporter (ABC transporter) Multi-drug Resistance Associated Protein 2 (ABCC2, MRP2). We demonstrate that MRP1 and MRP2 are divergent ABC- transporters that control transepithelial PMN migration through efflux of a distinct anti-inflammatory substance and the pro-inflammatory HXA3 in the context of Streptococcus pneumoniae infection. Enrichment of MRP2 on the plasma membrane requires detection of the bacterial virulence factors pneumolysin (PLY) and hydrogen peroxide. PLY and hydrogen peroxide not only coordinate MRP2 apical membrane enrichment but also influence HXA3-dependent PMN transepithelial migration. They influence migration through stimulation of epithelial intracellular calcium increases that are crucial for HXA3 production as well as MRP2 translocation to the plasma membrane. PLY and hydrogen peroxide are not sufficient in their signaling alone, however, and require at least one additional bacterial signal to induce HXA3/MRP2 proinflammatory activities.

<p><strong>Apstrakt je obrađen tehnologijama za optičko prepoznavanje teksta (OCR).</strong></p><p>Nastajanje i inhibicija stvaranja melanoidina u nečistim rastvorima saharoze je ispitivana na uzorcima neafinisanog i afinisanog C produkta na 80 [&deg;C].</p><p>Utvrdjena je zavisnost obrazovanja bojenih materija tipa melanoidina od vremena reakcije, od sadržaja suve materije, kao i od sadržaja i vrste aminokiselina.<br />Smanjenje obojenosti rastvora zavisi od koncentracije natrikum-sulfita i matematički je definisano Baule-Mitscherlichovim krivama zasićenja. Maksimalni efekat odbojavanja koji se može postići iznosi 30 [%] na 560 [nm], odn. 20 [%] na 420 [nm], ne razlikuje se za rastvore neafinisanog i afinisanog C produkta, a ostaje nepromenjen u vremenu od 1620 [min].</p><p>Povećanje koncentracike vodonik-peroksida je praćeno porastom količine bojenih materija prevedenih u leuko oblike, i produžavanjem vremena oksidacije. U odsustvu slobodnog vodonik-peroksida dolazi do reverzije boje rastvora.<br />Smanjenje obojenosti rastvora neafinisanog i afinisanog C produkta je signifikantno veće pri uzastopnom delovanju oksidacionog i redukcionog sredstva od smanjenja obojenosti postignutog njihovim pojedinačnim delovanjem. Efekti uzajamnog delovanja se ne menjaju u ispitivanom vremenu.</p> / <p><strong>Abstract was processed by technology for Optical character recognition (OCR).</strong></p><p>Reaction and inhibition of melanoidine formation in inpure solutions of sucrose were investigated on affinated and unaffinated C sugar samples carried out on 80 [&deg;C].<br />Melanoidin type colour formation dependending on reaction time, dry matter content and content and variety on amino acids has been studied.<br />Colour decrease in solutions depended on concentration of sodium sulphite and was mathematically defined by Baule-Mitscherlich curve of saturation. Maximum effect of colour decrease wich can be obtained was 30 [%] at 560 [nm], and 20 [%] at 420 [nm] wavelength respectively, and without any difference between affinated and unaffinated C sugar solutions, but it has stayed unchanged during reaction time of 1620 [min]. Hydrogen peroxide concentration rise was followed by increasing amounts of colour compounds transferred in leuco forms and by prolonged oxidation time. Absence of free hydrogen peroxide has induced the reverse formation of colour solutions.</p><p>Colour decrease in unaffinated and affinated C sugar solution was significantly larger, during subsequent treatment of oxidizing and reducing compounds, than during separate reactions. During reaction time the mutual treatment effect was unchangeable.</p>

During a rocket launch, the point at which the most thrust is needed is at lift-off where the rocket is the heaviest since it is full of propellant. Unfortunately, this is also the point at which rocket engines perform the most poorly due to the relatively high atmospheric pressure at sea level. The Thrust Augmenting Nozzle (TAN) investigated in this paper provides a solution to this dilemma. By injecting extra propellant into the nozzle but downstream of the throat, the internal nozzle pressure is raised and the thrust is increased, and the nozzle efficiency, or specific impulse is potentially improved as well. Using this concept, the payload capacity of a launch vehicle can be increased and provides an excellent option for single stage to orbit vehicles.

This Master’s thesis deals with isolating carbon nanoparticles from South Moravian lignite using "green" – environmentally friendly methods. This method consists of mechanical-chemical-thermal stressing of lignite using ultrasound, hydrogen peroxide and high temperatures. This work aims to develop recommendations on coal as a source of carbon nanoparticles and based on these recommendations, to design procedures for isolating nanoparticles from South Moravian lignite using environmentally friendly methods. The identified procedures were designed to meet carbon-based particles with an oxidized surface. From the results we can deduct that it is possible to use South Moravian lignite for the preparation of carbon nanoparticles. However, it will be necessary to modify the process further and also to optimize the purification of the obtained particles.

Elektroden aus Legierungen der Übergangsmetalle Vanadium, Titan und Niob und der reinen Metalle reagieren in Abhängigkeit von der Zusammensetzung und des mit ihnen im Kontakt stehenden wässrigen Elektrolyten in höchst unterschiedlicher Weise. Für eine systematische Untersuchung der elektrochemischen Eigenschaften der Elektroden wurden neben den reinen Metallen binäre und ternäre Legierungen aus Vanadium, Titan und Niob, die jeweils Vanadium enthalten, hergestellt. Es wurden zum ersten Mal zusammenhängend ihre physikalischen und chemischen Eigenschaften durch Strukturuntersuchungen und Untersuchungen der Zusammensetzung der Oberfläche sowie der Morphologie bestimmt. Von den, sich mit einer halbleitenden Oxidschicht überziehenden Metallen, wurden die Halbleitereigenschaften im Elektrolytkontakt studiert, die grundlegenden Korrosionseigenschaften sowie ihr elektrochemisches Verhalten als Elektrodenmaterial in potentiometrischen Zellen und durch Strom-Spannungsmessungen bestimmt. Zur Aufklärung der Kinetik der Oxidschichtbildung wurden potentiostatische Stromtransienten ermittelt und mit bekannten Modellen verglichen.