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1
Wareham, Lauren. "Carbon monoxide and carbon monoxide-releasing molecules : impacts on enterobacterial physiology." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/9450/.
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The emergence of carbon monoxide (CO) as the third ‘gasotransmitter’ (along with the more reactive nitric oxide (NO) and hydrogen sulfide (H2S)) in biology has led to a vast array of studies highlighting the anti-inflammatory, anti-proliferative and vasodilatory effects of the molecule, especially in mammalian studies of disease. The advent of CO-releasing molecules (CORMs) as means to safely deliver CO to biological systems has brought scope for the use of these molecules in microbiology, in particular, as antimicrobial compounds. It has been presumed that these activities are mediated by the release of CO. The antimicrobial activities of a number of CORMs have been demonstrated, mostly through the use of ruthenium-containing CORMs, such as CORM-3. Although these are effective antimicrobials, the use of a biologically foreign metal species renders these compounds less desirable for use in the clinic. In this thesis, a novel manganese-containing CORM, [Mn(CO)4{S2CNMe(CH2CO2H)}], CORM-401, is introduced and its actions against the gram-negative bacterium Escherichia coli are characterised. The compound has greater CO release characteristics that ruthenium CORMs, yet when introduced to bacterial cultures, proves less effective at killing. The CORM (inferred from the presence of manganese in excess of normal cellular pools) is shown to accumulate to high levels inside cells. CO is shown to bind to respiratory oxidases, but inhibition of respiration by CORM-401 is not observed; instead, stimulation of respiration in whole cells is seen. Transcriptomic analysis shows perturbation of cell stress responses and levels of cell-stress response proteins are elevated. CORM-401 leads to gross changes in ion and metal gradients across the cell membrane. It is hypothesised that the metal species of CORM compounds mediate the majority of the toxic effects reported in the literature. Further evidence that the interaction of CO released from CORMs with conventional haem targets cannot wholly explain the antimicrobial effects is also demonstrated in this thesis by the effects of CORM-3 on a haem-deficient mutant (hemA) of E. coli. This thesis also provides the first multi-level analysis of the effect of CO, without the intervention of CORMs, on E. coli cells. Transcriptomic analysis indicates that CO perturbs central metabolism and amino acid metabolism; in particular, gross perturbation of iron homeostasis is described, an effect confirmed by quantification of elevated siderophore production and sensitivity to iron-chelating compounds. Finally, the mechanism(s) of CORM-401 transport are investigated. Transport of CORMs into bacterial cells is an important aspect of their antimicrobial action that is often overlooked. Analysis of uptake is challenging, since radiolabelled CORMs are not available. However, assays of cellular uptake of CORM-401 (by metal detection) hint at a diffusion-based mechanism, although active transport systems cannot be disregarded at this time.
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Åberg, Anna-Maja. "Carbon monoxide in biological systems : An experimental and clinical study /." Umeå : Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1427.
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Patel, Ashvin P. "The cardiotoxicity of carbon monoxide." Thesis, University of Plymouth, 2003. http://hdl.handle.net/10026.1/1691.
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The mechanism(s) responsible for the cardiotoxicity of CO are not clear and do not appear to arise solely from tissue hypoxia. Tissue hypoxia is produced by CO binding to haemoglobin and reducing the amount of oxygen carried by the blood in vivo. CO-induced hypoxia in vivo may be responsible for producing conditions such as those found during ischaemia/reperfusion (l/R) injury. Reactive oxygen species (ROS) produced during l/R injury is established and responsible for cellular/tissue damage from the oxidative damage. We postulate that oxidative stress is responsible for the CO-associated cardiac morbidities found in some cases following severe acute exposure to CO. Isolated perfused rat hearts were used to investigate the physiological and biochemical changes in hearts following CO exposure. Hearts were perfused with buffer equilibrated with different mixtures of CO (0-0.05% CO for 30 minutes) in the presence of 21% oxygen during and after CO exposure (for 90 minutes), i.e. normoxic conditions were used throughout. Some hearts were perfused with water-soluble antioxidants (ascorbic acid and TroloxC) before and during the CO exposure. The reduced heart rate and perfusate flow suggest that CO may have a direct effect in heart tissue. Biochemical measurements suggest that no tissue hypoxia occurred under these conditions. The results provide evidence to suggest that oxidative stress occurred in ventricle tissue after CO exposure and was attenuated by the antioxidants. However, isolated rat liver mitochondria exposed to CO and/or hyperoxia showed no ROS production suggesting that mitochondria may not be a source of the oxidative stress. CO exposure may also produce altered myocardial energetics by oxidatively modifying and/or binding to myoglobin. Tissue damage initiated by CO-induced oxidative stress and hypoxia may potentiate ageing within heart tissue in vivo and could be responsible for producing the observed CO-associated heart morbidity in an MR-like injury.
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Pearson, Guy Neville. "RF excited carbon monoxide lasers." Thesis, Heriot-Watt University, 1988. http://hdl.handle.net/10399/981.
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Lin, Shioujenq Andrew. "The electrochemistry of carbon monoxide." Case Western Reserve University School of Graduate Studies / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=case1055944045.
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Kilchyk, Viktor. "Flammability limits of carbon monoxide and carbon monoxide-hydrogen mixtures in air at elevated temperatures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ64999.pdf.
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Wilson, Jayne Louise. "The anti-microbial effects of carbon monoxide and carbon monoxide-releasing molecule-3 (CORM-3)." Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/2901/.
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Intense research on carbon monoxide (CO) over recent years has demonstrated the increasing relevance of this gaseous signalling molecule in biology and medicine. A wide array of protective effects has been attributed to CO, including vasodilation, antiinflammation and anti-apoptosis. The advent of carbon monoxide-releasing molecules (CO-RMs) has revolutionised this field, providing a means by which the interaction between transition metals and carbonyls can be exploited to allow more controlled endogenous delivery of this noxious gas. It is via such compounds that the bactericidal activity of CO against a number of bacterial species has been most effectively explored. The best established CO-RM is the novel, water-soluble Ru(CO)3Cl(glycinate) (CORM- 3). In this thesis, CORM-3 is shown to inhibit respiration of diverse bacteria as well as Candida albicans and, interestingly, stimulates respiration of intact cells of Escherichia coli prior to inhibition. Proton translocation measurements (H+/O quotients, i.e. proton extrusion on pulsing anaerobic cells with O2, and the subsequent backflow of protons to the cytoplasm) show that respiratory stimulation cannot be attributed to dissipation of the protonmotive force, i.e. true uncoupling. Additionally, the bactericidal activity of CORM-3 is augmented in the absence of haem proteins and transcriptomic profiling of anaerobically-grown haem-deficient E. coli following exposure to CORM-3, and to a lesser extent inactivated CORM-3, reveals a multifaceted response. Of particular note is the up-regulation of iron-starvation response genes. Together, these data suggest that CORM-3 has targets additional to respiratory oxidases and that haem may act as a 'COsink', thereby providing protection against CO. Furthermore, CORM-3 is shown to be without effect on human macrophage functionality in a model of Neisseria meningitidis infection. This is the most complete study to date on the anti-microbial effects of a CO-RM and it highlights the multifaceted and complex action of these compounds. Importantly, control molecules depleted of CO reveal that CORM-3 toxicity is due to CO release; however, its potent anti-bacterial activity is not mimicked by CO gas. It is therefore becoming increasingly evident that there are several unidentified mechanisms underlying the effectiveness of CO-RMs in tackling microbial sepsis and pathogenesis.
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Jesse, Helen. "Carbon monoxide and carbon monoxide-releasing molecules as novel antibacterial agents : mechanisms of toxicity and resistance." Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/4809/.
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Carbon monoxide (CO) is commonly considered to be toxic due to the propensity of this gaseous molecule to bind to ferrous iron in haemoglobin and cytochromes, thereby inhibiting respiration and the transport of oxygen around the body. However, CO is produced endogenously by haem oxygenases and has various cytoprotective functions including being vasodilatory, anti-inflammatory and anti-apoptotic. The development of CO-RMs (Carbon Monoxide-Releasing Molecules), which are generally transition metal carbonyls that release CO under certain conditions, has facilitated research into the physiological effects of CO and the potential use of CO as a therapeutic agent. Furthermore, CO-RMs have been found to reduce significantly the viability of various Gram-positive and Gram-negative bacteria, which is thought to be caused in part by the binding of CO from CO-RMs to the terminal oxidases of aerobic respiratory chains. Interestingly, CO-RMs are known to elicit many effects distinct from those of CO gas, including acting as more potent bactericidal agents. This thesis aims to increase the current knowledge of the antibacterial effects of CORMs, with a particular focus on the interactions with respiration, oxidases and thiol compounds. In contrast to CO gas, CORM-3 was not preferentially inhibitory to respiration at low oxygen tensions; however, in accordance with the relative resistance of cytochrome bd-I to CO gas, this oxidase was found to be the most resistant of E. coli to respiratory inhibition by CORM-3, and possession of this oxidase conferred some protection against growth inhibition in the presence of this CO-RM. Inhibition of E. coli respiration by CORM-3 was photosensitive and light reduced significantly the toxic effects of this compound, suggesting that CO from CORM-3 binds to ferrous haems in a classical, light-sensitive manner. This supports the hypothesis that the binding of CO from CORM-3 to haemoproteins is largely responsible for killing by these compounds. However, in opposition to this hypothesis, the non-haem oxidase AOX from Vibrio fischeri was found to be hypersensitive to inhibition by CORM-3, but not to CO, emphasising the complex effects of these compounds. Data are presented to show that thiol-containing compounds, which have been widely reported to abolish the biological effects of CO-RMs, substantially reduce the uptake of ruthenium-containing CO-RMs. The generation of reactive oxygen species by CO-RMs is also demonstrated and investigated. Finally, the generation and preliminary characterisation of CO-RM-resistant E. coli mutants is described. This work was done with the aim of revealing previously unappreciated bacterial targets for CO-RMs. Sugar-transporting phosphotransferase systems were identified as a possible means of CO-RM entry into the bacterial cell.
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Bulat, Muhammer. "Molecular cluster cations of carbon monoxide and carbon dioxide." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://dx.doi.org/10.18452/16246.
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Diese Dissertation handelt vom metastabilen Zerfall und von der Oberflächenwechselwirkung im hyperthermalen Energiebereich relativ schwach gebundener molekularer Kohlenmonoxid und Kohlendioxid Clusterkationen mit einer Edelstahloberfläche und einer Siliziumoberfläche. Im Rahmen dieser Arbeit wurde ein hierfür geeignetes spezielles Flugzeitmassenspektrometer entwickelt und aufgebaut. Entwurf, numerische Optimierung der Auflösung, ionenoptische Simulationen und Aufbau der jeweiligen Komponenten wie Elektronenquellen, Beschleuniger, Ablenkplatten, Massenfilter und Reflektron werden detailliert beschrieben. Das entwickelte Flugzeitmassenspektrometer besitzt mit einer kompakten Gesamtfluglänge von ~1.5m eine hohe Massenauflösung von m/Delta m = 3000. Es bietet die Möglichkeit, eine Massentrennung von Clusterionen mit einer Größe von bis zu n = 190 vorzunehmen. Diese massenselektierten Clusterionen können daraufhin auf metastabilen Zerfall und auf ihre Wechselwirkung mit einer Oberfläche untersucht werden. Dazu wurden Kohlendioxid-Clusterionen mit nThis thesis deals with the metastable decay and the surface scattering in the hyperthermal energy range of relatively weakly bound molecular cluster cations. With carbon monoxide and carbon dioxide two related model systems were chosen for a systematic size dependent study. Surface impact experiments were carried out with stainless steel and silicon surfaces. Results were obtained by a new, reflectron time-of-flight mass spectrometer (Re-TOFMS). Additional to the experimental data we present in this work a detailed description of the instrumental design considerations, numerical optimization, ion optical simulations. Hence each ion optical component like electron guns, accelerator, deflector, mass gate and reflectron are described. Despite the compact dimensions with a total flight length of ~1.5m the developed instrument possesses a high mass resolution above m/Delta m = 3000. Additionally it offers the possibility to perform mass separation of big cluster ions with sizes n
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Ziolkowski, Lori. "Marine photochemical production of carbon monoxide." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0015/MQ57228.pdf.
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Blank, Jan Hendrik. "Carbon monoxide hydrogenation using ruthenium catalysts." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3470.
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Anker, Mathew. "Alkaline earth mediated carbon monoxide activation." Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720654.
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The aim of this thesis is to investigate the synthetic utility of insertion reactions with Group two complexes, specifically towards the activation of the small molecular gas; carbon monoxide. Extension of this Group two mediated reactivity into catalytic regimes exploits both σ–bond metathesis and insertion chemistries with hydride sources such as PhSiH3 or HBpin to generate value added chemicals. Chapter Two demonstrates organoisocyanates are readily converted to methyl amines through hydrodeoxygenation with HBpin in the presence of the β–diketiminato magnesium catalyst, Ib. A series of catalytically relevant species have been identified and fully characterized through stoichiometric reactivity studies. These data suggest that overall reduction and C–O activation occur through the intermediacy of well–defined magnesium formamidato and magnesium boryloxide species. This reaction is further explored through a DFT study which complements the experimental findings. Chapter Three explores the reaction between both β–diketiminato magnesium, Ih, and calcium, Ii, hydride complexes with carbon monoxide, resulting in the isolation of dimeric cis–enediolate species by the reductive coupling of two CO molecules. Under catalytic conditions with PhSiH3, an observable magnesium formyl species may be intercepted for the mild reductive cleavage of the CO triple bond to a methane analogue in the case of Ih. The related calcium formyl species could not be identified but under identical catalytic conditions reduced CO to a methoxysilane species, demonstrating the variability in the chemistries of the group two elements. Chapter Four investigates the carbonylation of a range of in situ generated β–diketiminato Ae–NRRʹ (Ae = Mg or Ca, R = H or Me and Rʹ = H, Alkyl or aryl) complexes, resulting in the isolation of a number of formamidate complexes and including a carbenic formamide dimagnesium species. The hydrodeoxygenation chemistry that was explored in Chapter Two is then extended to the range of isolated compounds providing a novel route to methyl amines.
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Wu, Wai-yin Helen. "A study of carbon monoxide exposure in selected populations in Hong Kong /." [Hong Kong : University of Hong Kong], 1994. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1381400X.
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Ali, Salar. "Effects of carbon monoxide and carbon monoxide-releasing molecules (CORMs) as adjuvants to antibiotics on Escherichia coli." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/15187/.
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Antibiotic-resistant pathogenic bacteria pose a major, growing public health risk. Antibiotics affect specific targets so that bacteria may develop cognate resistance to the target site. To cope with antibiotic resistance, combinatorial therapies involving two (or more) antimicrobial agents may be useful for minimizing antibiotic resistance phenomena. It is, therefore, necessary to investigate other antimicrobial agents. Carbon monoxide-releasing molecules (CORMs) have been shown to exert antimicrobial actions on several bacterial species both in the laboratory and in animal models. The aims of this thesis were to investigate the antibacterial effects of CORMs on the bacterial growth and viability for both strains of E. coli wild type (MG1655) and multidrug-resistant uropathogenic E. coli (EC958) and more importantly to test their interactions with antibiotics. The results revealed that CORMs have antimicrobial effects against both strains of E. coli. Importantly, a combination of sub-inhibitory concentrations of CORMs and antibiotics showed a significant potency on the action of conventional antibiotics with reduction of bacterial growth and viability. CO gas showed only slight antibacterial effects and there was no effect of CO gas on antibiotic activities when combined. Furthermore, conjunction of CORM-2 or CORM-3 with doxycycline, minocycline, gentamicin or chloramphenicol revealed that minimal inhibitory concentration (MIC) values of the antibiotics decreased between 16 - 640 fold with CORM-2 and 13 - 60 fold with CORM-3; the minimal bactericidal concentration (MBC) values were also reduced 2 - 6 fold with CORM-2 and 1 - 150 fold with CORM-3. Moreover, the drug interactions between CORMs and antibiotics were assessed using checkerboard microdilution methods, time-killing curves and Etests; the results revealed that CORMs have synergistic interactions with several antibiotics such as trimethoprim, novobiocin and doxycycline with fractional inhibitory concentration indexes (FICi) between 0.35 and 0.50. Real-time PCR data showed that CORM-2 significantly upregulates the transcription of recA and spy, which encode proteins for DNA recombination and repair and an envelope-stress-induced periplasmic protein respectively, However, there were no significant changes in the transcriptional level of sodA and katG, which encode for oxidative stress enzymes. Furthermore, ruthenium-based CORMs caused DNA degradation and also membrane leakage of nucleic acids in a concentration-dependent manner. Finally, CORM-2 produces a significant amount of ROS when assayed using a DCF-DC probe. However, using the HFP probe that selectively measures the generation of hydroxyl radical (OH^), we showed that CORM-2 does not produce OH^. Furthermore, the Amplex Red assay revealed that CORM-2 at lower concentrations was not able to produce H2O2 while 4 μM H2O2 was produced at 150 μM CORM-2. In conclusion, these findings reveal that the CO released from CORMs, especially CORM-2 and CORM-3 has bactericidal activity and, more importantly, these CORMs showed synergistic interactions with various antibiotics against both strains of E. coli.
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Newcomb, Alden. "EVALUATION OF THE PHYSIOLOGICAL EFFECTS OF REDUCED HYDROXOCOBALAMIN ON ACUTE CARBON MONOXIDE TOXICITY." VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3560.
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Carbon monoxide (CO) poisoning represents a global health threat responsible for hundreds of thousands of hospital visits and tens of thousands of deaths annually. Oxygen therapy is the only current approved treatment for CO poisoning. Previous work published in the 1970’s and research conducted in the VCURES lab group has indicated that a reduced form of vitamin B12, hydroxocobalamin (B12r), can potentially serve as an antidote for CO poisoning by converting CO bound to hemoglobin to carbon dioxide (CO2) and mitigating the deleterious neurological effects of CO poisoning. For the first time in documented literature we successfully used a Clark-type polarographic oxygen-sensitive electrode to demonstrate CO-induced decreases in brain tissue oxygen tension in anesthetized rats. Additionally, we demonstrated that B12r is capable of rescuing this CO-induced hypoxia and hypotension within 15 minutes of intraperitoneal administration with no adverse effects on blood chemistry.
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Gaubert, B., H. M. Worden, A. F. J. Arellano, L. K. Emmons, S. Tilmes, J. Barré, Alonso S. Martinez, et al. "Chemical Feedback From Decreasing Carbon Monoxide Emissions." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/626068.
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Understanding changes in the burden and growth rate of atmospheric methane (CH4) has been the focus of several recent studies but still lacks scientific consensus. Here we investigate the role of decreasing anthropogenic carbon monoxide (CO) emissions since 2002 on hydroxyl radical (OH) sinks and tropospheric CH4 loss. We quantify this impact by contrasting two model simulations for 2002-2013: (1) a Measurement of the Pollution in the Troposphere (MOPITT) CO reanalysis and (2) a Control-Run without CO assimilation. These simulations are performed with the Community Atmosphere Model with Chemistry of the Community Earth System Model fully coupled chemistry climate model with prescribed CH4 surface concentrations. The assimilation of MOPITT observations constrains the global CO burden, which significantly decreased over this period by similar to 20%. We find that this decrease results to (a) increase in CO chemical production, (b) higher CH4 oxidation by OH, and (c) similar to 8% shorter CH4 lifetime. We elucidate this coupling by a surrogate mechanism for CO-OH-CH4 that is quantified from the full chemistry simulations.
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Pickering, Julian Guy. "Catalytic reactions of hydrogen and carbon monoxide." Thesis, University of Cambridge, 1985. https://www.repository.cam.ac.uk/handle/1810/250868.
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Chang, I. S. "Carbon monoxide fermentation by Eubacterium limosum KIST612." Thesis, Swansea University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636225.
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Carbon monoxide (CO)-utilising acetogens were enriched and the isolate KIST612 was selected for its abilities to tolerate high CO and acetate concentration. The isolate KIST612 was identified as Eubacterium limosum based on the morphological and biochemical characteristics. E. limosum KIST612 produced acetate and butyrate from CO. The optimum temperature and pH for the growth and organic acids formations were 37°C and 7.0, respectively. This bacterium was cultivated on phosphate-buffered basal medium (PBBM) with CO as the sole energy and carbon source. In a batch fermentation using a serum vial, E. limosum KIST612 grew at the initial growth rate of 0.15-0.16 h-1 with Ks for dissolved CO of 0.14 mM. When sufficient CO was supplied using a bubble column reactor, the maximum growth rate of E. limosum KIST612 was 0.23 h-1. The bacterial growth rate was reduced in the presence of acetate. A membrane reactor was employed to allow cell recycling continuous sparging CO fermentation to organic acid product removal. The reactor system used was a bubble column type reactor, and the overall volumetric CO mass transfer coefficient (kLa) of the reactor was 72 h-1. When the dry cell weight was 5.25 g/L in the reactor, the bacterial cell concentration did not increase at a CO partial pressure lower than 74 kPa, though CO was consumed with organic acid produced. At this stage, supply of CO mass transfer rate was lower than CO requirement to support maximum cell growth, but higher than that to maintain culture. Since CO was supplied higher than maintenance requirement under atmospheric CO pressure, bacterial cell concentration increased to 9.5 g/L.
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Khalilzadeh, Rezaie Farnood. "Infrared emission spectroscopy of hot carbon monoxide." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4952.
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Gas giant exoplanets known as hot Jupiters orbit close to their parent stars and are heated to high temperatures. Their infrared spectra, measured by photometry during secondary eclipses, are dominated by carbon monoxide and methane, the principle reservoirs of carbon on these planets. The relative CO and CH[sub4] abundances inform us about temperature and pressure conditions and also about mixing by global winds driven by intense but asymmetric heating for these tidally locked bodies. Emission spectra collected during secondary eclipses, as the hot Jupiter passes behind its parent star, in principle allows a determination of the CO:CH[sub4] concentration ratio. Since hot Jupiters exist at temperatures of order 700 K, accurate model atmospheres require high temperature line lists for relevant molecules, for which existing data bases are apparently incomplete. Since the outer atmospheres of hot Jupiters are bombarded by intense ultraviolet radiation and energetic particles, there may even be a significant degree of ionization and non-equilibrium populations among the various molecular levels. Here we present high temperature emission spectra of CO obtained from a microwave discharge plasma, where the source of CO was carbon dioxide that dissociates under microwave heating. The spectrum was measured in the range 1800-2400 cm[super-1] at a resolution of 0.1 cm[super-1]. Vibrational transitions originating in up to the 13th vibrational level of the X [super1]greek upper case letter sigma][super+] ground electronic term were observed. From the J values for maximum intensity lines within the rotational fine structure, we obtain a temperature estimate of ~700 K, which is comparable to the atmospheric conditions of hot-Jupiters.ID: 030423212; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.)--University of Central Florida, 2011.; Includes bibliographical references (p. 79-80).
M.S.
Masters
Physics
Sciences
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Saucedo, Francisco Javier Villarreal. "RF excited carbon monoxide slab waveguide lasers." Thesis, Heriot-Watt University, 1996. http://hdl.handle.net/10399/1222.
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Bell, J. M. "Carbon monoxide oxidase from an autotrophic actinomycete." Thesis, University of Sunderland, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376540.
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Popova, Marina. "Visible Light-Triggered Carbon Monoxide-Releasing Molecules." DigitalCommons@USU, 2019. https://digitalcommons.usu.edu/etd/7500.
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Carbon monoxide (CO) is now well established as one of the signaling molecules in higher organisms, including humans. Due to its physiological roles, CO is now accepted as a potential therapeutic agent. The use of CO gas has been studied in multiple clinical trials. Vasodilation, anti-inflammatory, anti-apoptotic, anti-proliferative and cytoprotective effects are just a few of the pharmacological actions attributed to CO gas in various models of diseases. Use of inhaled CO gas as a therapeutic has many limitations which necessitate the development of a new approach for CO delivery. In order to handle CO safely, compounds that release CO (CO-releasing molecules, CORMs) have been developed. CORMs that release CO only when triggered, and with the ability to target certain tissue sites, are of particular interest. Our lab is developing molecules that release CO only when illuminated with visible light (photoCORMs). These photoCORMs are based on a motif found in naturally-occurring flavonols, which are chemical compounds found in wide variety of foods including fruits, vegetables, tea and dark chocolate.
The research presented in this dissertation outlines the results of studies on extended flavonols as CO release agents. The specific studies described herein focus on understanding visible light-induced CO-releasing flavonols in terms of their: a) structure/reactivity relationships, especially in biological environments; b) interactions with metal ions and proteins; c) reaction pathway of CO release; and d) their properties when combined with a CO-sensing motif.
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Chan, Sze Chi. "Novel photodeposited catalysts for carbon monoxide oxidation and preferential oxidation of carbon monoxide in the presence of hydrogen (PROX)." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 332 p, 2008. http://proquest.umi.com/pqdweb?did=1654493521&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Jeffers, Matt. "The Role of Carbon Nanotubes in the Hydrogenation of Carbon Monoxide." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/theses/301.
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This paper presents the culmination of an investigation on carbon nanotubes as catalysts for the hydrogenation of carbon monoxide. Carbon nanotubes (CNTs) have been found to have extraordinary physical properties and the potential for use in a variety of applications. They have been utilized as catalyst supports in many reactions, including the conversion of syngas to ethanol. The specific role played by CNTs in these reactions, aside from that of a support structure, has not been evaluated, however. Presented here are parametric studies on Fischer-Tropsch Synthesis with carbon nanotubes as active catalysts. The use of as-produced CNTs (containing trace amounts of iron from the synthesis process) resulted in a 100-fold increase in carbon monoxide conversion per unit mass of catalyst over a traditional Fe-Zn-K/γ-alumina catalyst. This value (CO conversion per unit mass of catalyst) was raised to nearly 1500 times as high as for Fe-Zn-K/γ-alumina when purified CNTs were used in the same FT synthesis. Because iron is a primary catalyst in the FT synthesis, it can be argued that the iron in the CNTs was responsible for the catalytic behavior. However, the iron content in the MWNTs (0.014 g, ≈ 5 mass%) and SWNTs (0.04 g, ≈ 27 mass%) compared to that of the traditional iron-loaded alumina support (2.5 g, ≈ 12.5 mass%), strongly suggests that iron alone cannot be responsible for the catalysis. Although single-walled nanotube (SWNT) catalysts provided high CO conversion, methane represented the bulk of the products. Conversely, multi-walled nanotubes (MWNTs) produced mostly liquid hydrocarbons and oxygenates, indicating that the CNT structure is an important factor in the hydrogenation of CO. The parametric experiments show that temperature, pressure and the syngas composition all play key roles in the distribution of liquid products. In general, an increase in temperature correlated to an increase in hydrocarbon chain length and the formation of more alcohols; above a certain temperature, the distribution shifted to 100% alcohols. Likewise, lower pressures resulted in hydrocarbons of shorter carbon chain length and at higher pressures, more alcohols were formed. Studies were also conducted on the effect of syngas composition and the effect of different types of CNTs. Syngas with 1:1 ratio (H2:CO) produced longer hydrocarbon chains than those produced by 3:1 syngas. The type of CNTs used in FT also affected the products but no clear relationships could be discerned.
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Duong, Hong Phong. "Highly selective electrocatalysts for carbon monoxide conversion to multi-carbon products." Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS467.
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La valorisation de dioxyde de carbone (CO2) par l’électrochimie est un méthodologie intéressante pour la synthèse de composés chimiques essentiels, par exemple l’éthylène et les alcools. Cependant, le problème de la formation de carbonate dans l’environnement basique de l’électrolyte limite l’application de la réduction de CO2. Récemment, il a été proposé un système composé par deux étapes (i) d’abord, la molécule de CO2 est réduite en monoxyde de carbone (CO) avec une efficacité faradique (FE) de 90% par une cellule électrochimique à oxyde solide. Et puis, le CO obtenu serait électrochimiquement réduit en éthylène avec une FE haute de 60%. Par conséquent, des recherches se développent pour trouver l’électrocatalyseur hétérogène sélectif pour la réduction de CO (COR). Dans cette thèse, certains électrocatalyseurs à base de cuivre qui présentent une activité élevée pour COR en éthylène, n- propanol et éthanol sont présentés. Le première chapitre présente un électrocatalyseur dendritique de cuivre qui a donné une sélectivité excellente pour COR en éthylène. Le système a réalisé la plus haute FE pour la production d’éthylène de 78% avec une densité de courant électrique appliqué de 100 mA cm-2 avec une efficacité énergétique (40,5%). Le deuxième chapitre présente une étude sur un électrocatalyseur en cuivre dopé à l’argent dérivé du nitrure de cuivre (CuAgN) qui a montré une FE excellente de 45% pour COR en n-propanol avec une densité de courant électrique de 150 mA cm-2. En comparaison avec les nanoparticules de cuivre, le nitrure de cuivre et les nanoparticules de cuivre dopé à l’argent, le catalyseur CuAgN possède la plus haute surface électrochimiquement active et la plus haute sélectivité pour la conversion de CO en n-propanol. Notamment, la sélectivité pour les produits liquides C2+ dépend de la concentration d’électrolyte KOH. Par les caractérisations in-situ et la modélisation théorique, il a été proposé que la présence de l’argent était capable d’améliorer les réactions de couplage C1-C2 entre deux intermédaires réactionnels sur la surface de CuAg. Enfin, d’après les études précédentes, les réactions de C1-C2 couplage semblent essentielles pour la formation des produits C3+, suggérant que la formation des produits C3+ pourrait être favorisée par ajout d’un substrat C2 comme l’acétaldéhyde ou le glyoxal pendant la COR.. Le troisième chapitre discute donc de l’effet d’un ajout d’acétaldéhyde dans le catholyte pendant la COR avec CuAgN, D-Cu et des nanoparticules de cuivre ou l’argent commerciaux comme catalyseursCarbon dioxide (CO2) valorization by electrolysis has shown its potential as an environmentally friendly and efficient method to synthesize value-added products like hydrocarbons and alcohols. However, the detrimental issue associated with carbonation in alkaline electrolyte limited the possibility to scale up CO2 electrolysis. Lately, a two-step concept, in which CO2 was firstly reduced into carbon monoxide (CO) with an industrially relevant Faradaic efficiency (FE) of 90% by a solid oxide electrochemical cell, then CO would be subsequently electrochemically reduced into ethylene with a high FE of 60% has been realized. As a result, there has recently been great attention focused on finding selective heterogeneous electrocatalysts to reduce CO into essential multi-carbon products. In this thesis, several copper-based electrocatalysts exhibiting high activity for CO conversion into ethylene, n-propanol and ethanol will be presented. The first chapter focuses on an original dendritic copper catalyst showing excellent selectivity for ethylene production from CO electrochemical reduction. The system exhibited the record FE for ethylene of 78% at an applied current density of 100 mA cm-2 with a record half-cell energy efficiency of 40.5%. In the second chapter, our attempt was focused on developing a nitride-derived silver- doped copper (CuAgN) electrocatalyst showing a high selectivity for CO electroreduction to n-propanol at the optimized condition (FE = 45%, an applied current density of 150 mA cm-2). In comparison with the bare copper nanoparticles, copper nitride and silver-doped copper nanoparticles, the CuAgN material possessed much higher electrochemically active surface area and CO conversion selectivity for n-propanol. Interestingly, the selectivity for C2+ liquid products of CuAgN was largely dependent on the concentration of KOH electrolyte. By employing in-situ characterization and computational modelling, a mechanism for n-propanol production was proposed as the presence of Ag could promote C1-C2 coupling reactions on the CuAg catalyst surface. Finally, according to the literature, C1-C2 coupling reactions were proposed as the key of C3+ products formation, thus the presence of a C2 substrate like acetaldehyde was presumed to boost C3+ products formation. The third chapter demonstrates the effect of an ab initio addition of acetaldehyde as a C2 substrate to CO electrolysis on the selectivity of the CuAgN, D-Cu catalysts, and commercial copper or silver nanoparticles
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Gottuk, Daniel. "The generation of carbon monoxide in compartment fires /." This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-06062008-165458/.
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Moxley, Janet Mary. "Carbon monoxide exchanges between soils and the atmosphere." Thesis, University of Edinburgh, 1996. http://hdl.handle.net/1842/28674.
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Carbon monoxide (CO) is an important atmospheric trace gas; it is the main sink for the hydroxyl radical which oxidises many other trace gases including methane, and is also involved in the production of tropospheric ozone. Oxidation by soil microorganisms accounts for approximately one fifth of the CO sink, the remainder being removed by reaction with hydroxyl. The size of the soil sink for CO is not accurately known, and the factors which affect the rate of oxidation are not fully understood. In addition, there is evidence that soils may be net sources of CO in some circumstances. This work investigated CO fluxes between soils and the atmosphere at a variety of scales, from laboratory incubations to measurements in the nocturnal boundary layer, to identify the major controlling factors and quantify fluxes. Laboratory incubations of a wide range of Scottish soils showed that the soil total organic carbon (TOC) content was the main factor influencing CO oxidation. This may reflect increases in microbial biomass with increasing TOC content. Multiple linear regression showed that water content was also important, and further investigation showed that there was an optimum water content for oxidation which was close to the field capacity. Static chamber measurements at arable and woodland sites showed that the most important factor affecting CO oxidation within a site was temperature. In several cases there was a negative linear relationship between CO uptake rate and temperature. This unusual relationship was attributed to simultaneous CO production from dead or senescent plant litter. In contrast, fallow arable land showed an optimum rate at approximately 10 °C. During May-June 1994 continuous measurements were made of the CO concentration in clean air. This followed a diurnal pattern with decreasing during the night, increasing in the early morning, and showing little change in the late morning and afternoon. The decrease in CO concentration at night was thought to be caused by deposition to the ground, and oxidation of CO by soil microorganisms. The mean deposition velocity was 1.1 x 10 -3 m s -1, which is in reasonable agreement with values obtained by other methods. A similar experiment in July-Aug 1996 found CO deposition with a mean deposition velocity of 1.8 x 10-3 m s -1.
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MacCallum, Stuart Neil. "Tropospheric carbon monoxide : satellite observations and their applications." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/4342.
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Carbon monoxide (CO) is present in the troposphere as a product of fossil fuel combustion, biomass burning and the oxidation of volatile hydrocarbons. It is the principal sink of the hydroxyl radical (OH), thereby affecting the concentrations of greenhouse gases such as CH4 and O3. Consequently, CO has an atmospheric lifetime of 1-3 months, making it a good tracer for studying the long range transport of pollution. Satellite observations present a valuable tool to investigate tropospheric CO. The Atmospheric InfraRed Sounder (AIRS), onboard the Aqua satellite, is sensitive to tropospheric CO in ~50 of its 2378 channels. This sensitivity to CO, combined with the daily global coverage provided by AIRS, makes AIRS a potentially useful instrument for observing CO sources and transport. An optimal estimation retrieval scheme has been developed for AIRS, to provide CO profiles from near-surface altitudes to 150 hPa. Through a validation study, using CO profiles from in-situ aircraft measurements, this retrieval scheme has been shown to provide CO observations with strong correlations to in situ measurements. Compared to the operational AIRS v4 CO product this retrieval scheme is shown to provide total column CO retrievals with a reduced bias relative to the in situ measurements (~ -10% to ~ -1%). In addition, the optimal estimation retrieval is shown to provide improved estimation and characterization of the retrieval errors. Further validation work has been carried out through comparison with the established CO observations from the MOPITT instrument, onboard the Terra satellite. Good agreement (correlation coefficient > 0.9, and bias < 1.0 ppbv) between the instruments is observed in the mid-troposphere. At this level, the optimal estimation scheme is shown to remove a positive bias of ~10 ppbv, relative to MOPITT, that is present in the AIRS v4 CO product. The AIRS instrument is also shown to be less sensitive to CO in the lower troposphere than MOPITT. AIRS is also demonstrated to provide fewer pieces of independent information about the vertical structure of CO at tropical latitudes, where higher thermal contrast increases the sensitivity of MOPITT. Through time series analysis, the capability of AIRS to detect seasonal trends in CO is demonstrated. The potential of AIRS to be used to track, both horizontal and vertical, CO transport is explored. AIRS is shown to be capable of tracking horizontal transport, and to have potential to track vertical transport when combined with another satellite sensor.
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Khansawai, Paveena. "Chemical modification of alkene-carbon monoxide alternating copolymers." Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/12362.
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Reactions of isolated carbonyl groups in ethene/propene-carbon monoxide alternating copolymers were accomplished by acid-catalysed condensation with alkene-1,2-diols (ethane-, propane-, butane- and hexane-1,2-diols) affording alkene-dioxolane copolymers. Oximation with hydroxylamine, O- methylhydroxylamine and O-benzylhydroxylamine resulted in complete conversion of the carbonyl groups to their oxime derivatives. In addition, the conversions of polyketoximes, derived from ethene/propene-carbon monoxide copolymers, to 1-acteoxyiminotrimethylene and 1-benzoxyimino-trimethylene polymers were achieved by treatment with acetic anhydride and benzoyl chloride, respectively. Reaction of 1,4-dione units in ethene/propene-carbon monoxide alternating copolymers has been investigated. Paal-Knorr reactions with aniline, benzylamine and glycine ethyl ester yielded poly(alkenepyrrole) derivatives. The conversion of the carbonyl groups in ethene/propene-carbon monoxide alternating copolymers to methoximes allowed directed a-substitution reactions to be carried out on the polymer backbone. Treatment with n-butyllithium followed by addition of electrophiles (e.g. iodomethane, 1-iodopropane, 1-bromobutane, benzyl bromide and allyl bromide) afforded the polymer products in which 20-38% of the a-syn methylene hydrogens were substituted. The syn selectivity of the lithiation process was established b treatment of the polymethoxime with BuLi/[O-2H]methanol and confirmed by the presence of deuterium signal in the 2H-NMR spectrum corresponding to those observed for the model compounds. Beckmann rearrangement reactions of model compounds [2.5-bis(tosyloxyimino)hexane, 2,5-bis(mesyloxyimino)hexane and 2,5-bis(hydroxyimino)hexane] were investigated and resulted in rearrangement products: N,N'-ethanediyl-bis-acetamide, N-acetyl-b-alaninemonomethylamide and N,N'-dimethylsuccinamide.
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Gottuk, Daniel T. 1967. "The generation of carbon monoxide in compartment fires." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/38324.
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For the purpose of fire analysis and fire safety engineering, the development of empirical correlations for major species yields in compartment fires has become an important priority due to the inability to calculate these quantities from first principles. Studies of simplified upper layer environments have shown that major species production rates can be correlated with the equivalence ratio in what is known as the Global Equivalence Ratio concept (GER). Due to the simplification in these past experiments, it was not known if the GER concept was valid for compartment fires. Therefore, there was a need to determine if correlations existed between major species yields and the equivalence ratio for actual compartment fires. Since the flow of toxic gases from a room poses a hazard to building occupants, it was also important to determine if correlations for CO yield outside of a compartment on fire exist, particularly when external burning occurs.
A 2.2 m³ test compartment was used to investigate the burning of four fuels (hexane, PMMA, spruce and flexible polyurethane foam) in compartment fires. The test compartment was specially designed with a two-ventilation path system which allowed the direct measurement of the plume equivalence ratio (the ratio of the fuel volatilization rate to the air entrainment rate normalized by the stoichiometric fuel-to-air ratio).
Empirical correlations between the upper layer yield of major species and the plume equivalence ratio were shown to exist The results reveal that the production of CO is primarily dependent on the compartment flow dynamics (i.e., the equivalence ratio) and upper layer temperature. A chemical kinetics study indicated that increased compartment temperature affects upper layer species yields in two ways 1) the generation of species in the plume is changed and 2} oxidation of post-flame gases in the layer is affected. The correlations developed in the compartment fifes were qualitatively similar to those developed by Beyler for simplified upper layer environments. However, quantitative differences existed and are explained by the temperature effect.
The species yields downstream of hexane compartment flues were investigated and compared to upper layer yields. Results showed that downstream CO yields can be correlated to the plume equivalence ratio when taking into account the occurrence of external burning. When sustained external buning occurred for equivalence ratios greater than 1.7, downstream CO yields were reduced to 10 to 25 percent of the upper layer value. Results are very encouraging in indicating that an ignition criterion based on lean flammability limits is useful in predicting the flammability of upper layer gases in compartment fires. An ignition index value of 1.3 indicated the occurrence of sustained external burning and, thus, a reduction of CO, for the hexane fires studied.Ph. D.
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Wieczorek, Christopher John. "Carbon Monoxide Generation and Transport from Compartment Fires." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/28006.
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The aim of the present research was to gain a better understanding of the species generation and transport from enclosure fires. The species generation experiments were conducted with a half-scale ISO 9705 enclosure with three different ventilation conditions and heat release rates ranging from 50 kW to 500 kW. The transport study was conducted with a 6.1 m long hallway connected to the compartment in a head-on configuration. All measurements were performed at the compartment or hallway exit plane during the steady-state period of the fire. Measurements included species mole fractions of oxygen, carbon dioxide, carbon monoxide, and unburned hydrocarbons, along with gas pressure (used to determine gas velocities) and gas temperatures.
Species mappings performed at the exit plane of the compartment indicated that the exiting species are not spatially uniform. Horizontal and vertical gradients in the species mole fractions were observed for all ventilation conditions and heat release rates examined.
Predictive techniques developed previously were applied to the data obtained in the present study and were determined to be inappropriate for situations were the plume equivalence ratio was not equal to the global equivalence ratio. A new methodology for predicting species levels at the exit plane of an enclosure was developed. The proposed methodology correlates the species yields based on the combustion within the compartment as a function of a non-dimensional heat release rate. The non-dimensional heat release rate is based on the fuel load and geometrical parameters of the enclosure. The present methodology in applicable to situations where a well-mixed uniform layer is not present and the overall global conditions are of interest.
Species transport to remote locations was also examined. Experiments were conducted with the baseline ventilation at x = 0 m (the compartment/hallway interface) and three different ventilation conditions at x = 6.1 m (end of hallway). The three ventilation conditions consisted of the narrow, baseline, and wide doorways. Experiments were conducted for heat release rates of 85 kW, 127 kW, and 150 kW. The results from the tests indicated that, for over-ventilated compartment fires, the hallway and hallway ventilation had no impact on the species generation within the compartment. This allows the correlations developed from the compartment study to be applied to more complex scenarios.
Differences in species mole fractions between x = 0 m and x = 6.1 m were shown to be a result of air entrainment into the upper layer within the hallway, which acted as a dilutent or as a source of oxygen for further oxidation reactions. For non-dimensional heat release rates less than 1.0, the reduction in carbon monoxide levels along the hallway was a result of dilution, while for non-dimensional heat release rates greater than or equal to 1.0 the reduction in carbon monoxide levels along the hallway was a combination of dilution and further oxidation reactions.Ph. D.
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Menon, Sadan Suneesh. "Visualization of Carbon Monoxide Particles Released from Firearms." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1514115394832639.
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Scheuermann, Margaret L. "Reactivity of PtII "Pincer" Complexes with Carbon Monoxide." Scholarship @ Claremont, 2008. https://scholarship.claremont.edu/scripps_theses/6.
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ABSTRACT Upon addition of carbon monoxide (CO) to a solution of (k-N, C, N-2, 6-bis(diethylaminomethyl)-phenyl)methyl platinum(II),[NCN]PtMe,(1), a ligand arm is displaced to form [SP-4-2] ((k-N,C-2,6-bis(diethylaminomethyl)-phenyl) carbonmethyl platinum(II), N[CN]Pt(CO)(Me),(2). Addition of CO to a THF solution of 2 results in the formation of [SP-4-3]((k-N,C-2,6-bis(diethylaminomethyl)-phenyl)acylcarbonyl platinum(II),N[CN]pt(Ac)(CO),(3). In THF ,2 partially isomerizes in the presence of CO to form [SP-4-4]((k-N,C-2,6-bis(diethylaminomethyl)-phenyl)carbonylmethyl platinum(II), N[CN]Pt(Me)(CO).(2’).in equilibrium with 2(K=ca.2 at 100 degree celcius). In the absence of CO, only trace isomerization was observed. Thermolysis of 3 results in the formation of 2 and 2’ , while a reaction of 3 with trimethylamine N-oxide results exclusively in the formation of 2. Both three and five-coordinate intermediates have been shown to be accessible ,leading to two proposed mechanisms for the thermolysis of 3 and the microscopic reverse of this reaction.
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Barati, Sedeh Mansoor Coley Kenneth S. "Kinetics of carbon monoxide-carbon dioxide reaction with iron oxide containing slags." *McMaster only, 2005.
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Roderique, Joseph. "STUDIES ON THE REACTION OF HIGH-DOSE HYDROXOCOBALAMIN AND ASCORBIC ACID WITH CARBON MONOXIDE: IMPLICATIONS FOR TREATMENT OF CARBON MONOXIDE POISONING." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/469.
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Based upon experimental evidence from the 1970’s we proposed that a reduced form of hydroxocobalamin should be capable of producing carbon dioxide (CO2) from carbon monoxide (CO) in blood, and that this conversion should be detectable. Using resonance raman spectroscopy we demonstrated that a mixture of hydroxocobalamin and ascorbic acid could create the reduced form of hydroxocobalamin. We used a closed-loop circulation system with a hollow-fiber membrane oxygenator to produce carboxyhemoglobin. Using sensitive gas monitoring equipment to the gas-out port of the oxygenator we analyzed the CO and CO2 concentrations coming from the oxygenator. The mixture of hydroxocobalamin and ascorbic acid caused a 5-fold increase in the CO2 concentration of the gas-out flow, in comparison to baseline and negative controls. These findings offer initial support for the potential use of a mixture of hydroxocobalamin and ascorbic acid as an injectable antidote for carbon monoxide poisoning.
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Daza, Yolanda Andreina. "Closing a Synthetic Carbon Cycle: Carbon Dioxide Conversion to Carbon Monoxide for Liquid Fuels Synthesis." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6079.
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CO2 global emissions exceed 30 Giga tonnes (Gt) per year, and the high atmospheric concentrations are detrimental to the environment. In spite of efforts to decrease emissions by sequestration (carbon capture and storage) and repurposing (use in fine chemicals synthesis and oil extraction), more than 98% of CO2 generated is released to the atmosphere. With emissions expected to increase, transforming CO2 to chemicals of high demand could be an alternative to decrease its atmospheric concentration. Transportation fuels represent 26% of the global energy consumption, making it an ideal end product that could match the scale of CO2 generation. The long-term goal of the study is to transform CO2 to liquid fuels closing a synthetic carbon cycle.
Synthetic fuels, such as diesel and gasoline, can be produced from syngas (a combination of CO and H2) by Fischer Tropsch synthesis or methanol synthesis, respectively. Methanol can be turned into gasoline by MTO technologies. Technologies to make renewable hydrogen are already in existence, but CO is almost exclusively generated from methane. Due to the high stability of the CO2 molecule, its transformation is very energy intensive. Therefore, the current challenge is developing technologies for the conversion of CO2 to CO with a low energy requirement.
The work in this dissertation describes the development of a recyclable, isothermal, low-temperature process for the conversion of CO2 to CO with high selectivity, called Reverse Water Gas Shift Chemical Looping (RWGS-CL). In this process, H2 is used to generate oxygen vacancies in a metal oxide bed. These vacancies then can be re-filled by one O atom from CO2, producing CO. Perovskites (ABO3) were used as the oxide material due to their high oxygen mobility and stability. They were synthesized by the Pechini sol-gel synthesis, and characterized with X-ray diffraction and surface area measurements. Mass spectrometry was used to evaluate the reducibility and re-oxidation abilities of the materials with temperature-programmed reduction and oxidation experiments. Cycles of RWGS-CL were performed in a packed bed reactor to study CO production rates.
Different metal compositions on the A and B site of the oxide were tested. In all the studies, La and Sr were used on the A site because their combination is known to enhance oxygen vacancies formation and CO2 adsorption on the perovskites. The RWGS-CL was first demonstrated in a non-isothermal process at 500 °C for the H2-reduction and 850 °C for the CO2 conversion on a Co-based perovskite. This perovskite was too unstable for the H2 treatment. Addition of Fe to the perovskite enhanced its stability, and allowed for an isothermal and recyclable process at 550 °C with high selectivity towards CO. In an effort to decrease the operating temperature, Cu was incorporated to the structure. It was found that Cu addition inhibited CO formation and formed very unstable oxide materials.
Preliminary studies show that application of this technology has the potential to significantly reduce CO2 emissions from captured flue gases (i.e. from power plants) or from concentrated CO2 (adsorbed from the atmosphere), while generating a high value chemical. This technology also has possible applications in space explorations, especially in environments like Mars atmosphere, which has high concentrations of atmospheric carbon dioxide.
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Sriramulu, Suresh. "Rates of the surface reactions in methanol and carbon monoxide electrooxidation : experimental measurements and kinetic modeling /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/9904.
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Savant, Deepa. "Multidimensional NMR studies of terpolymers poly(ethylene-co-vinyl acetate-co-carbon monoxide) and poly(ethylene-co-1-hexene-co-carbon monoxide)." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1153685162.
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Lau, Steffen, Katharina Salffner, and Hans-Gerd Löhmannsröben. "Isotopic resolution of carbon monoxide and carbon dioxide by NIR diode laser spectroscopy." Universität Potsdam, 2006. http://opus.kobv.de/ubp/volltexte/2006/1013/.
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Near-infrared (NIR) absorption spectroscopy with tunable diode lasers allows the simultaneous detection of the three most important isotopologues of carbon dioxide (12CO2, 13CO2, 12C18O16O) and carbon monoxide (12CO, 13CO, 12C18O). The flexible and compact fiber-optic tunable diode laser absorption spectrometer (TDLAS) allows selective measurements of CO2 and CO with high isotopic resolution without sample preparation since there is no interference with water vapour. For each species, linear calibration plots with a dynamic range of four orders of magnitude and detection limits (LOD) in the range of a few ppm were obtained utilizing wavelength modulation spectroscopy (WMS) with balanced detection in a Herriott-type multipass cell. The high performance of the apparatus is illustrated by fill-evacuation-refill cycles.
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Barletta, Julien. "[11C]Carbon Monoxide in Rhodium-/Palladium-Mediated Carbonylation Reactions." Doctoral thesis, Uppsala universitet, Institutionen för biokemi och organisk kemi, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6654.
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Methods for the 11C-labeling of carbonyl compounds applicable in the preparation of radiotracers for Positron Emission Tomography (PET) are described. To this end [11C]carbon monoxide at low concentration was used in transition metal- mediated reactions. Stille couplings were employed in the synthesis of [carbonyl-11C]ketones from methyl and aryl halides with [11C]carbon monoxide. The synthesized [carbonyl-11C]ketones were obtained from the corresponding organostannanes with analytical radiochemical yields up to 98%. A number of synthetic routes were designed using [11C]carbon monoxide and rhodium complexes. Nitrene intermediates were generated from azides and reacted via a rhodium-mediated carbonylation reaction as a general synthetic route to [carbonyl-11C]isocyanates, versatile precursors. [carbonyl-11C]Isocyanate reacted via nucleophilic attack of an amine to form N,N’-diphenyl[11C]urea in 82% analytical radiochemical yield, ethyl phenyl[11C]carbamate was synthesized by the same route, using ethanol as the nucleophile, in 70% radiochemical yield. [11C]Isocyanate was also able to react in a [2+3] cycloaddition with ethylene oxide to form 3-phenyl[carbonyl-11C]oxazolidin-2-one in over 80% analytical radiochemical yield. This method was applied to the synthesis of a potential efflux system tracer [11C]hydroxyurea in 38% isolated radiochemical yield and the derivative 1-hydroxy-3-phenyl[11C]urea in 35% isolated radiochemical yield. Carbene intermediates, generated from diazo compounds, were reacted with [11C]carbon monoxide in the rhodium-mediated synthesis of [carbonyl-11C]ketenes. [carbonyl-11C]Ketene intermediates were utilised in the synthesis of diethyl[carbonyl-11C]malonate, from ethyl diazoacetate and ethanol. The product was obtained with a 20% isolated radiochemical yield. Alkylation of diethyl[carbonyl-11C]malonate, with ethyliodide and tetrabutylammonium fluoride, was successfully accomplished and diethyl diethyl[carbonyl-11C]malonate was synthesized in 50% analytical radiochemical yield. Several (carbonyl-13C)compounds were also synthesized using the described methods as a way of characterizing the position of the label using 13C-NMR.
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French, Catherine Louise. "Electron momentum spectroscopy of carbon monoxide and hydrogen sulfide." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26257.
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The binding energies and momentum profiles for each of the valence orbitals of CO and H₂S have been measured by high momentum resolution electron momentum spectroscopy.
The experimental momentum profiles are compared on a quantitative basis within the Target Hartree-Fock Approximation to theoretical calculations using SCF wavefunctions ranging in quality from minimal basis to Hartree-Fock limit. Calculated momentum distributions for the 5σ orbital of CO are shown to be very basis set dependant while calculated momentum distributions of the CO 3σ, 4σ and 1π orbitals change very little with improvements in the wavefunction beyond the double-zeta level. The CO 1π orbital is not very well described in the low momentum region even at the Hartree-Fock limit with basis set saturation including diffuse functions. While the 4a₁, and 2b₂ momentum profiles of H₂S are well described using even minimal basis calculations, diffuse functions must be included in the basis set to describe the 2b₁, and 5a₁, momentum profiles.
The experimental momentum profiles of H₂S are also compared with full ion-neutral overlap calculations incorporating correlation in the ground state and correlation and relaxation in the final ion state. These calculations are very similar to the Hartree-Fock level momentum distributions, indicating that correlation is not very important in describing the momentum profiles of H₂S. The binding energy spectra and momentum profiles of the inner valence region of both CO and H₂S are studied in detail. Peaks in the CO binding energy spectrum at 24.1 and 28.3 eV are assigned as satellites 4σ and 1π main lines respectively while the structure above 30 eV is shown to be predominantly due to satellites of the 3σ orbital. The intense structure in the inner valence region of H₂S is found to arise predominantly from the 4a₁, orbital. The assignments of the inner valence spectra of both molecules is confirmed within experimental uncertainties by the spectroscopic sum rule.Science, Faculty of
Chemistry, Department of
Graduate
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Pierce, Donna. "Formation and destruction of carbon monoxide in cometary comae." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3422.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2006.Thesis research directed by: Astronomy. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Grant, Aoife. "Measurements and modelling of tropospheric hydrogen and carbon monoxide." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.528087.
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Pearson, Danita Marjorie. "Genetic analysis of carbon monoxide utilization in Pseudomonas thermocarboxydovorans." Thesis, University of Sunderland, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239937.
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Yip, Yuen Sing. "Oscillatory behaviour in the catalytic oxidation of carbon monoxide." Thesis, University of Salford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327982.
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Mirzaei, Ali Akbar. "Low temperature carbon monoxide oxidation using copper containing catalysts." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266493.
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Foster, Carina Elizabeth. "Reactions of [FeFe]-hydrogenase with carbon monoxide and formaldehyde." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:a1d43c4a-861a-4bb0-88ce-2edf4c334f79.
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The use of H2 as an energy carrier has in recent years been identified as a promising future solution to the current energy crisis. Hydrogenases are metalloenzymes found in many microorganisms and are used to catalyse the reversible inter-conversion of protons and H2. These enzymes and their synthetic analogues have been recognised as a way to facilitate the use of H2 as a fuel. A major challenge to the future use of these catalysts is their reactions with small molecule inhibitors, such as oxygen and carbon monoxide. Detailed understanding of the structure and catalytic mechanism of these highly efficient catalysts is vital for the design of bio-inspired functional analogues for use in technological applications. In this thesis electrochemical studies of three [FeFe]-hydrogenases are presented, performed using the technique of protein film electrochemistry. The strong potential dependence of the reaction of these hydrogenases with carbon monoxide and formaldehyde is characterised and rationalised. These studies provide compelling evidence for the formation of a previously ambiguous super-reduced state of [FeFe]-hydrogenase at low potential. This state is shown to be active and stable, and it is proposed that this state is involved in catalytic H2 production. This super-reduced state is shown to have a high affinity for the reversible binding of formaldehyde, but a very low affinity for both carbon monoxide and oxygen. Activation of carbon monoxide inhibited [FeFe]-hydrogenase can be very rapidly induced by the application of a sufficiently reducing potential. These enzymes, considered to be oxygen sensitive, are shown to be extremely tolerant to irreversible oxygen damage at very reducing potentials where the super-reduced state is formed.
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Younkman, Lora Birkefeld. "Development and Characterization of Ceramic-Based Carbon Monoxide Sensors /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1273585788.
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Nemalapuri, Vijay Krishna. "Impact of Traffic Operations on Carbon Monoxide Emissions Analysis." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282322424.
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Zhang, Mengru. "Nickel-Catalyzted Alternating Copolymerization of Carbon Monoxide and Ethylene." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1428024122.
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