Denim production is one of the leading sub-sectors of textile industry which basically generates highly colored indigo dyeing effluents. In the present study, ozonation was applied to the indigo-dyeing effluent(COD=820 mg/L / color=5500 Pt-Co), and to the whole effluent from a denim-producing plant before(COD=2750 mg/L / color=3950 Pt-Co) and after(COD=800 mg/L,color=3700 Pt-Co) biological treatment for degradation/detoxification purposes. Ozonation was also tried in the wastewater of the plant(COD=3100 mg/L / color=4500 Pt-Co) that would be produced after some foreseen cleaner production measures / caustic recovery and reusing of dyeing process wastewater. When applied to indigo-dyeing wastewater / ozonation provided 95% color and 61% COD removals at 1320 mg/h ozone dose within 60 minutes The optimum pH was evaluated as 4 when indigo-dyeing wastewater exposed to ozonation at different pHs(1.6-12.3). On the other side, ozonation applied as pre-treatment to the plant effluent provided 86% color and 46% COD removals with 3240 mg/h ozone dose in 70 minutes. Less satisfactory results were obtained when ozonation was tried in the wastewater after measures, with 86% color and 31% COD removals at 3960 mg/h ozone dose in 80 minutes. When applied to the biologically-treated effluent / at 420 mg/h ozone dose and within 40 minutes, ozonation removed 47% of influent COD and 96% of influent color indicating better performance of ozonation in postoxidation. In order to assess possible improvements on ozonation with the addition of H2O2, different concentrations were tried, but no significant improvement was obtained. The improvement in BOD5/COD index was also determined for the ozonetreated plant effluent to measure the effects of ozonation on biodegradability and found out that BOD5/COD ratio has improved to 0.39 from 0.22.

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.

No description available.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 128-159).

Thesis (M.S.)--Mississippi State University. Department of Chemistry. / Title from title screen. Includes bibliographical references.

M. Tech. Metallurgical Engineering. / Aims to provide a mineralogical basis for understanding the galvanic dissolution and interaction of sulphide ores in presence of hydrogen peroxide using electrochemical technique. The research aim to achieve the following objectives: study the mineralogical characteristics of different sulphide ores ; study the sulphuric acid dissolution behaviour of the sulphide ores in the presence of hydrogen peroxide and to investigate the interaction of the mineralogy on the ores and hydrogen peroxide during dissolution.

This dissertation discusses the influence of nitrogen doping (N-doping) on the electronic and catalytic properties of carbon nanotubes (CNTs). These properties have been studied using a variety of techniques, in order to both qualitatively and quantitatively analyze the relationship between the nitrogen concentration and observed properties. Chapter 1 provides a general overview of CNTs and N-doping and details some of the previous research from our group. Chapter 2 discusses the assembly and characterization of free-standing electrode mats, which are used in order to understand the intrinsic physicochemical properties of the material without relying on the secondary influence of another conductive support. Raman microscopy, X-Ray photoelectron spectroscopy, scanning and scanning-tunneling electron microscopy, as well as electrochemical methods were all used to demonstrate the viability of the mat electrodes for further experiments. Chapter 3 addresses the examination of a range of nitrogen concentrations in order to better understand the effects of nitrogen concentration on the electrochemical and electrical properties such as the differential capacitance, density of states at the Fermi level (D(E[subscript F])), bulk conductivity and work function. These properties were studied using a variety of techniques, including UV-photoelectron spectroscopy, electrochemical impedance spectroscopy and conductive four point probe. Chapter 4 investigates the inherent catalysis of the nitrogen doped CNTs (N-CNTs) with respect to O2 reduction, and a complex mechanism is proposed. Electrochemical methods such as cyclic and linear sweep voltammetries as well as thermo-gravimetric analysis and gasometric analysis were all employed to determine heterogeneous decomposition rates as well as to detect intermediates of the O₂ reduction reaction. Chapter 5 discusses the electrocatalytic degradation of free cyanide (CN⁻) at the N-CNT mat electrodes. These results both provide further support for the mechanism discussed in Chapter 4, and present the opportunity for a potential application of N-CNTs for environmental purposes. Specifically, spectroscopic and electrochemical methods, in conjunction with theoretical models show both that the presence of CN⁻ does not inhibit O2 reduction, and that it can be effectively converted to cyanate (OCN⁻) at the N-CNT electrodes. Future work involving the assembly and characterization of transparent N-CNT films is discussed in Chapter 6. / text

The process of radiation induced corrosion of copper is not well understood. The most obvious situation where the knowledge of this process is crucial is in a deep repository for high level spent nuclear fuel where the fuel will be sealed inside copper canisters. The radiation will penetrate the canisters and be absorbed by the surrounding environment. In this study gamma irradiations of polished and pre-oxidized copper cubes in anoxic pure water, air of 60-100 % RH and in humid argon were performed. The copper surfaces were examined using IRAS, XPS, cathodic reduction, SEM, AFM, and Raman spectroscopy. The concentration of copper in the reaction solutions was measured using ICP-OES.  Also the formation of oxidative species caused by radiation absorption of water was studied by numerical simulations using MAKSIMA software. The corrosion of copper during gamma irradiation vastly exceeds what is expected. The production of oxidative species caused by radiation absorption of water is hundreds of times too low to explain the amount of oxidized copper. A possible explanation for this mismatch is an enhanced radiation chemical yield of HO· on the copper surface. Another one is an increased surface area due to oxidation of copper. One speculation is that HO· interacting with the copper oxide can cause oxidation of the metal. If the thermodynamic driving force is large enough then electrons can be conducted from the metal through the oxide to the oxidant. A dramatic increase in surface area together with an increased interfacial yield of HO· might explain the radiation enhanced corrosion process. / <p>QC 20151022</p>

Clostridium difficile is a common and potentially fatal cause of antibiotic-associated diarrhoea and pseudomembranous colitis worldwide. It has been isolated from patients and their surroundings, in healthcare facilities and from the community. C. difficile is able to survive for many months on inanimate surfaces in the form of spores. PCR ribotyping is used in the UK to characterise and identify strain diversity. Investigating how the most problematic strains respond to cleaning regimes may influence the control of disease. This work used the University Hospitals of Leicester Trust as a case study for this purpose of understanding the epidemiology of this pathogen within healthcare facilities. Five individual agar media were compared based on their abilities to recover and resuscitate damaged ribotype 027 spores, a strain associated with disease outbreaks and increased severity. Controlled laboratory experiments with a sub-lethal dose of a germicide were conducted before C. difficile recovery from hospital wards. An additional two sampling campaigns acquired environmental strains. C. difficile isolation after routine cleaning demonstrated the inefficiency of the current recovery regime as C. difficile spores were recovered using direct contact plates, enrichment broths, and resuscitation media. This study used layering of non-selective agar over selective agar, identifying a potential link in the proportions of media following the use of sponges in environmental sampling. All strains were characterised by ribotyping; ribotype 027 was isolated from all sampling cohorts. A four-month epidemiological study was conducted into the ribotype prevalence and distribution from C. difficile-positive faecal specimens. A second survey investigated these effects with a modification of C. difficile detection from faecal samples. Hydrogen peroxide vapour is currently being explored as a means of decontamination of healthcare-associated infections. Inactivation kinetics of ribotype 027 spores were analysed in response to vapour and liquid exposure of hydrogen peroxide. No reports thus far have explored such kinetics and controlled decontamination with both clinical and non-clinical strains. Evidence strongly suggests spores can be inactivated with its application. Furthermore, this study revealed there appears to be significant differences in susceptibility and inactivation of different C. difficile ribotypes.

Τα τελευταία χρόνια μια πληθώρα ερευνητικών εργασιών συσχετίζει την παραγωγή των δραστικών μορφών οξυγόνου (ROS) με ποικίλες κυτταρικές λειτουργίες. Στο επίπεδο του κυττάρου, η παραγωγή ROS δύναται να προκληθεί τόσο υπό την επίδραση φυσιολογικών ερεθισμάτων (όπως ορμόνες και κυτταροκίνες) όσο και από εξωγενείς παράγοντες (όπως μικροοργανισμοί και ακτινοβολία). Η αυξημένη παραγωγή ROS ενέχεται στην παθογένεση διαφόρων ασθενειών, όπως του καρκίνου, της αθηροσκλήρωσης και της ρευματοειδούς αρθρίτιδας. Αν και σε υψηλές συγκεντρώσεις οι ROS καθίστανται κυτταροτοξικές, σε χαμηλά επίπεδα φαίνεται να δρουν ως ειδικά μόρια που συμμετέχουν στη μεταγωγή σήματος. Ανάμεσα στις ROS, ιδιαίτερο ενδιαφέρον προσελκύει το Η2Ο2, το οποίο λόγω της σχετικής σταθερότητας, της έλλειψης πολικότητας και του μικρού μοριακού μεγέθους, είναι ιδανικός υποψήφιος μεσολαβητής στη μεταγωγή σήματος στο εσωτερικό των κυττάρων. Η heparin affin regulatory peptide (HARP) είναι αυξητικός παράγοντας με σημαντικό ρόλο στην ανάπτυξη του καρκίνου και στην αγγειογένεση. Στην παρούσα εργασία μελετήθηκε η επίδραση του Η2Ο2 στον πολλαπλασιασμό και τη μετανάστευση των ανθρώπινων καρκινικών κυττάρων προστάτη LNCaP και των ενδοθηλιακών κυττάρων από φλέβα ομφάλιου λώρου (HUVEC), καθώς και στην αγγειογένεση in vivo στο μοντέλο της χοριοαλλαντοϊκής μεμβράνης (CAM) εμβρύου όρνιθας. Μελετήθηκε επίσης η πιθανή εμπλοκή της HARP στη δράση του Η2Ο2. Βρέθηκε ότι εξωγενώς χορηγούμενο Η2Ο2 επάγει τον πολλαπλασιασμό και τη μετανάστευση των κυττάρων HUVEC και την αγγειογένεση in vivo στην CAM εμβρύου όρνιθας. Επιπρόσθετα, το Η2Ο2 αύξησε τα επίπεδα της πρωτεΐνης HARP in vitro και in vivo. Το U0126 και η κουρκουμίνη ανέστειλαν τόσο την αύξηση των επιπέδων της πρωτεΐνης HARP, όσο και τον πολλαπλασιασμό των HUVEC που επάγονται από το Η2Ο2. Σε συμφωνία με τα παραπάνω, βρέθηκε ότι το Η2Ο2 επάγει τον πολλαπλασιασμό και τη μετανάστευση των κυττάρων LNCaP. Επιπλέον, προκάλεσε αύξηση των επιπέδων του mRNA και της πρωτεΐνης HARP, με τρόπο εξαρτώμενο από τη συγκέντρωση και το χρόνο. Η HARP φαίνεται να μεσολαβεί στις δράσεις του Η2Ο2, καθώς σε κύτταρα LNCaP στα οποία έχει κατασταλεί η έκφρασή της δεν εκδηλώθηκαν οι διεγερτικές δράσεις του Η2Ο2. Η κουρκουμίνη και ολιγονουκλεοτίδια-δολώματα έναντι του AP-1 ανέστειλαν τόσο την έκφραση της HARP, όσο και τον πολλαπλασιασμό και τη μετανάστευση των κυττάρων LNCaP που επάγονται από το Η2Ο2. Μετά από εισαγωγή της ρυθμιστικής περιοχής του γονιδίου της HARP σε πλασμιδιακό φορέα ανοδικά γονιδίου αναφοράς, το Η2Ο2 αύξησε με χρόνο-εξαρτώμενο τρόπο τη δραστηριότητα του υποκινητή του συγκεκριμένου γονιδίου. Η επαγωγική αυτή δράση ανεστάλη όταν εισήχθησαν σημειακές μεταλλαγές σε τουλάχιστον μία από τις δύο πιθανές αλληλουχίες δέσμευσης του AP-1. Η επίδραση του Η2Ο2 φαίνεται να οφείλεται στη δέσμευση των Fra-1, JunD και της ενεργού μορφής της c-Jun στη ρυθμιστική περιοχή του γονιδίου της HARP. Συμπερασματικά, στην παρούσα εργασία ενισχύεται η άποψη ότι η HARP διαδραματίζει σημαντικό ρόλο στον πολλαπλασιασμό και τη μετανάστευση των κυττάρων. Επίσης, προτείνεται ότι το γονίδιο της HARP παρουσιάζει ευαισθησία σε μεταβολές της οξειδωτικής κατάστασης του κυττάρου, καθώς η έκφρασή της επάγεται σε χαμηλές συγκεντρώσεις Η2Ο2. Τέλος, αναδεικνύεται η εμπλοκή συγκεκριμένων συμπλόκων του AP-1 στη ρύθμιση της μεταγραφικής δραστηριότητας του γονιδίου της HARP και των επακόλουθων βιολογικών δράσεων σε απόκριση στο Η2Ο2. / A growing body of evidence correlates the production of Reactive Oxygen Species (ROS) with many aspects of cell functions. Cellular ROS production can be augmented by the action of hormones, cytokines, and other physiological stimuli and also by external factors, such as xenobiotics or irradiation. Increased ROS production has been implicated in the pathogenesis of several diseases, such as cancer, atherosclerosis, rheumatoid arthritis and ischemia/reperfusion injury. Although ROS may be cytotoxic when produced in excess, at moderate levels they may act as specific signalling molecules. Among different ROS, H2O2 possesses the properties of relative stability, neutrality and small size, which make it an ideal candidate for a signalling molecule. Heparin affin regulatory peptide (HARP) is a mitogenic and angiogenic growth factor and plays a significant role on tumor growth and angiogenesis. In the present study we found that exogenous H2O2 significantly induced human umbilical vein endothelial cell (HUVEC) proliferation and migration, and angiogenesis in the in vivo chorioallantoic membrane assay. In addition, it increased HARP protein amounts in vitro and in vivo. U0126 and curcumin abrogated both H2O2-induced HARP protein amounts increment and HUVEC proliferation. In the same line, exogenous H2O2 significantly induced human prostate cancer LNCaP cell proliferation and migration. Moreover, H2O2 significantly increased HARP mRNA and protein amounts in a concentration- and time-dependent manner. HARP seems to be involved in the stimulatory effect of H2O2, since the latter had no effect on stably transfected LNCaP cells that did not express HARP. Curcumin and AP-1 decoy oligonucleotides abrogated both H2O2-induced HARP expression and LNCaP cell proliferation and migration. H2O2 increased luciferase activity of the 5’-flanking region of the HARP gene introduced in a reporter gene vector, an effect that was abolished when even one of the two putative AP-1 binding sites of the HARP promoter was mutated. The effect of H2O2 seems to be due to binding of Fra-1, JunD and phospho-c-Jun to the HARP promoter. In conclusion, H2O2 up-regulates HARP expression through the induction of specific AP-1 dimers, leading to increased cell proliferation and migration.