The majority of deaths and injuries in compartment fires result from inhalation of the toxic gas, carbon monoxide (CO), especially in locations remote from the burning compartment. This causes the transport and oxidation of CO in burning buildings to become an important topic. Studies have been conducted to determine the toxic environments produced inside, and in locations remote from, a burning compartment; however, no studies have investigated the composition of the exhaust gases during transport to remote locations. The goal of this study was to investigate fire exhaust gas transport through a hallway to determine the important parameters affecting the efficiency of sustained external burning in oxidizing toxic gases, including the hydrodynamic effects of different hallway configurations. Underventilated compartment fire experiments were performed with a compartment exhausting along the axis of a hallway. The design of the compartment allowed direct measurement of the global equivalence ratio which was used as a main correlating parameter. Characteristic global equivalence ratios and an ignition index concept were investigated to determine when sustained external burning would occur. Gas sampling was performed downstream of the hallway to determine the overall efficiency of sustained external burning, and in the hallway to provide detailed data on the processes occurring in the hallway. The oxidation of the exhaust gases traveling through the hallway was determined to vary among different species, and also to be very sensitive to the hydrodynamic mixing between the rich exhaust plume and the cooler ambient air in the hallway. In general, the overall oxidation of hydrocarbons was much more complete than for CO or soot. The gas temperatures in the hallway and fuel vaporization rate were also determined to affect oxidation in the hallway. Variations in the hallway inlet and exit soffits affected the hydrodynamic structure of the exhaust plume and oxidation efficiencies, with the inlet soffit exhibiting the strongest effect. / Master of Science

The carbon monoxide dehydrogenase complex was purified from acetate-grown Methanosarcina thermophila. This complex made up greater than 10% of the cellular protein and the native enzyme formed aggregates with a Mr of approximately 1,000,000. The enzyme contained five subunits of different molecular weight suggesting a multifunctional enzyme complex. Nickel, iron, cobalt, zinc, inorganic sulfide, and a corrinoid were present in the complex. The electron paramagnetic resonance spectrum of CO-reduced enzyme at 113K contained g values of 2.073, 2.049, and 2.028. Isotopic substitution with ⁶¹Ni, ⁵⁷Fe, or ¹³Co resulted in broadening of the spectrum consistent with a Ni-Fe-C spin-coupled complex. Acetyl-CoA caused a perturbation of the signal that was not caused by acetyl-phosphate or mercaptoethanol indicating acetyl-CoA is a physiological substrate. Cell extracts from acetate-grown M. thermophila contained CO-oxidizing:H₂-evolving activity 16-fold greater than extracts of methanol-grown cells. CO-oxidizing:H₂-evolving activity was reconstituted upon combination of: (i) CO dehydrogenase complex, (ii) a ferredoxin, and (iii) purified membranes with associated hydrogenase and b-type cytochrome. The ferredoxin was a direct electron acceptor for the CO dehydrogenase complex. The molecular weight of the isolated protein was 16,400, and the apparent minimum molecular weight was 4,900. The ferredoxin contained 2.8 ± 0.56 Fe atoms and 1.98 ± 0.12 acid-labile sulfide. UV-visible absorption maxima were 395 and 295 nm with a A₃₉₅/A₂₉₅ ratio range of 0.80 to 0.88. The N-terminal amino acid sequence revealed a 4-cysteine cluster, similar to other Fe:S centers that coordinate a Fe:S center. A CH₃-B₁₂:HS-CoM methyltransferase activity was characterized in extracts of acetate- and methanol-grown cells. The activity from extracts of acetate-grown M. thermophila was stable at 70°C for 30 minutes. The activity in cell extracts of acetate- and methanol-grown cells was fractionated with ammonium sulfate treatment and FPLC phenyl superose chromatography. Two peaks of methyltransferase activity were observed in each cell extract sample following phenyl superose fractionation. / Ph. D.

The study of the products of combustion continues to have real-world relevance since the primary cause of death in building fires is smoke inhalation, with the majority of deaths from carbon monoxide, CO, poisoning. An experimental study was conducted to examine upper-layer structure plus provide an initial characterization of a new compartment with a doorway. An additional study of the relationship between heat flux from external burning in a hallway and levels of carbon monoxide is also reported. Tests were conducted in a new ½ scale ISO compartment with a fully scaled doorway, using n-hexane pool fires within the center of the compartment. Upper-layer sampling at eight locations in the compartment has shown that the compartment upper-layer is relatively uniform in species mole fractions, yields, and temperature. Sampling in the front upper-layer of the compartment was performed for a series of experiments where the equivalence ratio was varied. Temperatures, species mole fractions, species yields, and doorway flows were found to have definite trends, which agreed with previous studies. The heat flux study utilized a reduced scale compartment with a separate inlet and an exit vent, which connected into the side of an attached hallway, forming an L-shape. For two cases of a deep and shallow hallway upper-layer a direct relationship between flames in the upper-layer and total heat flux was measured. High heat flux was found to only denote those areas were flames are present and is not related to the levels of CO present or oxidized in the hallway. / Master of Science

No

No / Carbon monoxide (CO) is firmly established as an important, physiological signalling molecule as well as a potent toxin. Through its ability to bind metal-containing proteins, it is known to interfere with a number of intracellular signalling pathways, and such actions can account for its physiological and pathological effects. In particular, CO can modulate the intracellular production of reactive oxygen species, NO and cGMP levels, as well as regulate MAPK signalling. In this review, we consider ion channels as more recently discovered effectors of CO signalling. CO is now known to regulate a growing number of different ion channel types, and detailed studies of the underlying mechanisms of action are revealing unexpected findings. For example, there are clear areas of contention surrounding its ability to increase the activity of high conductance, Ca2+-sensitive K+ channels. More recent studies have revealed the ability of CO to inhibit T-type Ca2+ channels and have unveiled a novel signalling pathway underlying tonic regulation of this channel. It is clear that the investigation of ion channels as effectors of CO signalling is in its infancy, and much more work is required to fully understand both the physiological and the toxic actions of this gas. Only then can its emerging use as a therapeutic tool be fully and safely exploited.

Yes / Induction of the antioxidant enzyme heme oxygenase-1 (HO-1) affords cellular protection and suppresses proliferation of vascular smooth muscle cells (VSMCs) associated with a variety of pathological cardiovascular conditions including myocardial infarction and vascular injury. However, the underlying mechanisms are not fully understood. Over-expression of Cav3.2 T-type Ca2+ channels in HEK293 cells raised basal [Ca2+]i and increased proliferation as compared with non-transfected cells. Proliferation and [Ca2+]i levels were reduced to levels seen in non-transfected cells either by induction of HO-1 or exposure of cells to the HO-1 product, carbon monoxide (CO) (applied as the CO releasing molecule, CORM-3). In the aortic VSMC line A7r5, proliferation was also inhibited by induction of HO-1 or by exposure of cells to CO, and patch-clamp recordings indicated that CO inhibited T-type (as well as L-type) Ca2+ currents in these cells. Finally, in human saphenous vein smooth muscle cells, proliferation was reduced by T-type channel inhibition or by HO-1 induction or CO exposure. The effects of T-type channel blockade and HO-1 induction were non-additive. Collectively, these data indicate that HO-1 regulates proliferation via CO-mediated inhibition of T-type Ca2+ channels. This signalling pathway provides a novel means by which proliferation of VSMCs (and other cells) may be regulated therapeutically. / This work was supported by the British Heart Foundation.

Yes / A 16-electron iridium organometallic is reacted with carbon monoxide to form an 18-electron CO-adduct. This CO-adduct is stable for weeks in the solid state, but quickly reverts to its parent 16-e complex in tetrahydrofuran solution, releasing CO(g). Using a simple methodology, we show that this gas can subsequently be used to perform a carbonylation reaction on another molecule. / Royal Society; Academy of Medical Sciences/the Wellcome Trust/the Government Department of Business, Energy and Industrial Strategy/the British Heart Foundation Springboard Award

An experimental study was conducted to measure the effects of oxygen entrainment on the transport of CO in building fires, and to develop a procedure for estimating CO levels during a building fire. Experiments were performed with an insulated 1/4-scale room connected to the side of a 1/4-scale hallway forming a L-shape. Measurements of CO, unburned hydrocarbons (UHC), CO₂, and O₂ concentrations and temperature were performed within the compartment, the hallway and post-hallway in the exhaust duct. The level of CO transported to remote locations from the burning room was hypothesized to be most significantly affected by the oxygen entrainment into the compartment fire gases entering the hallway. With a fixed size opening connecting the compartment to the hallway, the oxygen entrainment was varied by changing the depth of the oxygen deficient hallway upper-layer. In experiments where compartment fire gases entered the hallway completely surrounded by oxygen deficient combustion gases, post-hallway CO yields were measured to be as much as 23% greater than CO yields measured inside the compartment, despite the presence of external burning. With deep upper-layers in the hallway, geometric effects were not observed to significantly affect the transported level of CO. Instead, the CO level was a function of the compartment stoichiometry and the occurrence of external burning. / Ph. D.

The catalytic effects of selected iron phases (metal, oxides, sulfides, and carbides) on the Boudouard reaction (2 CO = CO₂ + C) were studied, in an effort to more fully understand the disintegration of refractories when exposed to CO for long periods of time. Based on computer generated equilibrium phase maps (SOLGASMIX program), experimental kinetic data including activation energies and x-ray diffraction data of iron phases, the following conclusions were reached: (1) Ferric oxide (Fe₂O₃ ) is most catalytic; (2) Active iron atom generated by the reduction of Fe₂O₃ is a catalyst for carbon monoxide disintegration; (3) The catalytic process consists of the adsorption of CO, the formation of intermediates FeC, Fe₂C , and Fe₃C , and the decomposition of these intermediates. / Ph. D.

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.