"A process to capture carbon dioxide from air to reduce its atmospheric concentration and to mitigate climate change is studied. It is based on the absorption of carbon dioxide in a sodium hydroxide solution, its precipitation as calcium carbonate, and its release as pure gas stream through oxy-fuel calcination. The process utilizes existing commercial technologies wherever possible, particularly in the case of the absorber, whose design is carried out in detail. The analysis allows deriving material and energy balances for the whole process and determining energy demands that can be used for a technical, economical, and environmental feasibility evaluation of the technology. In particular, it indicates that the real specific energy demand is larger than the heat released to emit the same amount of CO2 by the combustion of coal, and smaller than that of methane. "

"N(2)O is a potent greenhouse gas and stratospheric reactant that has been steadily on the rise since the beginning of industrialization. It is an obligatory inorganic metabolite of denitrifying bacteria, and some production of N(2)O is also found in nitrifying and methanotrophic bacteria. We focus this review on the respiratory aspect of N(2)O transformation catalysed by the multicopper enzyme nitrous oxide reductase (N(2)OR) that provides the bacterial cell with an electron sink for anaerobic growth. Two types of Cu centres discovered in N(2)OR were both novel structures among the Cu proteins: the mixed-valent dinuclear Cu(A) species at the electron entry site of the enzyme, and the tetranuclear Cu(Z) centre as the first catalytically active Cu-sulfur complex known. Several accessory proteins function as Cu chaperone and ABC transporter systems for the biogenesis of the catalytic centre. We describe here the paradigm of Z-type N(2)OR, whose characteristics have been studied in most detail in the genera Pseudomonas and Paracoccus. Sequenced bacterial genomes now provide an invaluable additional source of information. New strains harbouring nos genes and capability of N(2)O utilization are being uncovered. This reveals previously unknown relationships and allows pattern recognition and predictions. The core nos genes, nosZDFYL, share a common phylogeny. Most principal taxonomic lineages follow the same biochemical and genetic pattern and share the Z-type enzyme. A modified N(2)OR is found in Wolinella succinogenes, and circumstantial evidence also indicates for certain Archaea another type of N(2)OR. The current picture supports the view of evolution of N(2)O respiration prior to the separation of the domains Bacteria and Archaea. Lateral nos gene transfer from an epsilon-proteobacterium as donor is suggested for Magnetospirillum magnetotacticum and Dechloromonas aromatica. In a few cases, nos gene clusters are plasmid borne. Inorganic N(2)O metabolism is associated with a diversity of physiological traits and biochemically challenging metabolic modes or habitats, including halorespiration, diazotrophy, symbiosis, pathogenicity, psychrophily, thermophily, extreme halophily and the marine habitat down to the greatest depth. Components for N(2)O respiration cover topologically the periplasm and the inner and outer membranes. The Sec and Tat translocons share the task of exporting Nos components to their functional sites. Electron donation to N(2)OR follows pathways with modifications depending on the host organism. A short chronology of the field is also presented."

"Supersonic molecular beams have been used to determine the yield of CO from the partial oxidation of CH(4) on a Rh(111) catalytic substrate, CH(4)+(12)O(2)-->CO+2H(2), as a function of beam kinetic energy. These experiments were done under ultrahigh vacuum conditions with concurrent molecular beams of O(2) and CH(4), ensuring that there was only a single collision for the CH(4) to react with the surface. The fraction of CH(4) converted is strongly dependent on the normal component of the incident beam's translational energy, and approaches unity for energies greater than approximately 1.3 eV. Comparison with a simplified model of the methane-Rh(111) reactive potential gives insight into the barrier for methane dissociation. These results demonstrate the efficient conversion of methane to synthesis gas, CO+2H(2), are of interest in hydrogen generation, and have the optimal stoichiometry for subsequent utilization in synthetic fuel production (Fischer-Tropsch or methanol synthesis). Moreover, under the reaction conditions explored, no CO(2) was detected, i.e., the reaction proceeded with the production of very little, if any, unwanted greenhouse gas by-products. These findings demonstrate the efficacy of overcoming the limitations of purely thermal reaction mechanisms by coupling nonthermal mechanistic steps, leading to efficient C-H bond activation with subsequent thermal heterogeneous reactions."

"Declining estrogen production after menopause causes osteoporosis in which the resorption of bone exceeds the increase in bone formation. We recently found that mice deficient in the -subunit of follicle-stimulating hormone (FSH) are protected from bone loss despite severe estrogen deficiency. Here we show that FSH-deficient mice have lowered TNF levels. However, TNF-deficient mice are resistant to hypogonadal bone loss despite having elevated FSH, suggesting that TNF is critical to the effect of FSH on bone mass. We find that FSH directly stimulates TNF production from bone marrow granulocytes and macrophages. We also explore how TNF up-regulation induces bone loss. By modeling the known actions of TNF, we attribute the high-turnover bone loss to an expanded osteoclast precursor pool, together with enhanced osteoblast formation. TNF inhibits osteoblastogenesis in the presence of ascorbic acid in culture medium, but in its absence this effect becomes stimulatory; thus, ascorbic acid reverses the true action of TNF. Likewise, ascorbic acid blunts the effects of TNF in stimulating osteoclast formation. We propose that hypogonadal bone loss is caused, at least in part, by enhanced FSH secretion, which in turn increases TNF production to expand the number of bone marrow osteoclast precursors. Ascorbic acid may prevent FSH-induced hypogonadal bone loss by modulating the catabolic actions of TNF."

"During petroleum refining, a large number of products are generated which have varying chemical and physical properties. These are known in the industry as petroleum streams. In order to characterize their carcinogenic activity, a number of these commercially produced streams were administered to C3H/HeJ mice in chronic dermal bioassays. The bioassays were conducted using one of two study designs: the first set of test materials was applied for a lifetime and the second set for 24 months. In the lifetime study, the last mice in the test groups survived for periods of 31 to 32 months. Middle distillates, boiling in the range 115-390 degrees C, were found to decrease the lifespan of exposed mice compared to controls or streams of higher and lower boiling ranges. These middle distillate streams included straight run kerosine, hydrodesulfurized middle distillate, straight run middle distillate, light catalytic cracked distillate, and 90/10% and 70/30% mixtures of the last two. The middle distillate streams also proved to be active as carcinogens, with tumor incidence ranging from 16 to 67%. Light alkylate naphtha, heavy catalytic reformed naphtha, vacuum residuum, and unleaded gasoline did not demonstrate significant carcinogenic potency. Heavy thermal cracked naphtha, heavy catalytic cracked naphtha, and hydrotreated light naphthenic distillate were dermal carcinogens of low potency in this study. Administration of light catalytic cracked naphtha led to a low incidence of very late developing tumors with a mean latency of 118 weeks. Application of the 0.1% solution of catalytic cracked clarified oil in toluene did not result in a significant incidence of tumors, but the 10% solution caused almost 100% mortality and 100% tumor incidence in 12 months. There was no correlation between carcinogenic potency and the indices of irritation, alopecia, erythema, and scabbing. Only two of the streams tested, hydrotreated light naphthenic distillate and 10% catalytic cracked clarified oil, contain polynuclear aromatic hydrocarbons (PNAs) and may be presumed to be complete carcinogens. The middle distillates and heavy naphthas are nonmutagenic and essentially free of PNAs. Their activity may result from promotion of already-initiated skin sites. Where comparisons could be made, reducing the exposure period from a lifetime (29-32 months) to 24 months did not change the evaluations of stream carcinogenicity except in the case of light catalytic cracked naphtha where six of the seven mice that developed tumors did so after 24 months."

...."However, to become commercially viable, PEFCs have to overcome the barrier of high catalyst cost caused by the exclusive use of platinum and platinum-based catalysts6,7,8 in the fuel-cell electrodes. Here we demonstrate a new class of low-cost (non-precious metal)/(heteroatomic polymer) nanocomposite catalysts for the PEFC cathode, capable of combining high oxygen-reduction activity with good performance durability. Without any optimization, the cobalt-polypyrrole composite catalyst enables power densities of about 0.15 W cm-2 in H2-O2 fuel cells and displays no signs of performance degradation for more than 100 hours. The results of this study show that heteroatomic polymers can be used not only to stabilize the non-precious metal in the acidic environment of the PEFC cathode but also to generate active sites for oxygen reduction reaction."