Formation of submicron oxide widths on aluminum in the presence of keV electron beams and CO2 or N2O

Investigation of electrochemical carbon monoxide sensor monitoring of anesthetic gas mixtures.

Methane hydrate exists in huge amounts in certain locations, in sea sediments and the geological structures below them, at low temperature and high pressure. Production methods are in development to produce the methane to a floating platform. There it can be reformed to produce hydrogen and carbon dioxide, in an endothermic process. Some of the methane can be burned to provide heat energy to develop all needed power on the platform and to support the reforming process. After separation, the hydrogen is the valuable and transportable product. All carbon dioxide produced on the platform can be separated from other gases and then sequestered in the sea as carbon dioxide hydrate. In this way, hydrogen is made available without the release of carbon dioxide to the atmosphere, and the hydrogen could be an enabling step toward a world hydrogen economy.

This is the second update of a Cochrane Review first published in 2013 and last updated in 2017. Laparoscopic surgery is now widely performed to treat various abdominal diseases. Currently, carbon dioxide is the most frequently used gas for insufflation of the abdominal cavity (pneumoperitoneum). Although carbon dioxide meets most of the requirements for pneumoperitoneum, the absorption of carbon dioxide may be associated with adverse events. Therefore, other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum. To assess the safety, benefits, and harms of different gases (e.g. carbon dioxide, helium, argon, nitrogen, nitrous oxide, and room air) used for establishing pneumoperitoneum in participants undergoing laparoscopic abdominal or gynaecological pelvic surgery. We searched CENTRAL, Ovid MEDLINE, Ovid Embase, four other databases, and three trials registers on 15 October 2021 together with reference checking, citation searching, and contact with study authors to identify additional studies. We included randomised controlled trials (RCTs) comparing different gases for establishing pneumoperitoneum in participants (irrespective of age, sex, or race) undergoing laparoscopic abdominal or gynaecological pelvic surgery under general anaesthesia. We used standard methodological procedures expected by Cochrane. We included 10 RCTs, randomising 583 participants, comparing different gases for establishing pneumoperitoneum: nitrous oxide (four trials), helium (five trials), or room air (one trial) was compared to carbon dioxide. All the RCTs were single-centre studies. Four RCTs were conducted in the USA; two in Australia; one in China; one in Finland; one in Iran; and one in the Netherlands. The mean age of the participants ranged from 27.6 years to 49.0 years. Four trials randomised participants to nitrous oxide pneumoperitoneum (132 participants) or carbon dioxide pneumoperitoneum (128 participants). None of the trials was at low risk of bias. The evidence is very uncertain about the effects of nitrous oxide pneumoperitoneum compared to carbon dioxide pneumoperitoneum on cardiopulmonary complications (Peto odds ratio (OR) 2.62, 95% CI 0.78 to 8.85; 3 studies, 204 participants; very low-certainty evidence), or surgical morbidity (Peto OR 1.01, 95% CI 0.14 to 7.31; 3 studies, 207 participants; very low-certainty evidence). There were no serious adverse events related to either nitrous oxide or carbon dioxide pneumoperitoneum (4 studies, 260 participants; very low-certainty evidence). Four trials randomised participants to helium pneumoperitoneum (69 participants) or carbon dioxide pneumoperitoneum (75 participants) and one trial involving 33 participants did not state the number of participants in each group. None of the trials was at low risk of bias. The evidence is very uncertain about the effects of helium pneumoperitoneum compared to carbon dioxide pneumoperitoneum on cardiopulmonary complications (Peto OR 1.66, 95% CI 0.28 to 9.72; 3 studies, 128 participants; very low-certainty evidence), or surgical morbidity (5 studies, 177 participants; very low-certainty evidence). There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum (3 studies, 128 participants; very low-certainty evidence). One trial randomised participants to room air pneumoperitoneum (70 participants) or carbon dioxide pneumoperitoneum (76 participants). The trial was at high risk of bias. There were no cardiopulmonary complications, serious adverse events, or deaths observed related to either room air or carbon dioxide pneumoperitoneum. AUTHORS' CONCLUSIONS: The evidence is very uncertain about the effects of nitrous oxide, helium, and room air pneumoperitoneum compared to carbon dioxide pneumoperitoneum on any of the primary outcomes, including cardiopulmonary complications, surgical morbidity, and serious adverse events. The safety of nitrous oxide, helium, and room air pneumoperitoneum has yet to be established, especially in people with high anaesthetic risk.

Laparoscopic surgery is now widely performed to treat various abdominal diseases. Traditionally, the first step during laparoscopic surgery is to distend the abdomen, including entry into the abdomen and then insufflation with a gas (pneumoperitoneum), providing sufficient operating space to ensure adequate visualization of the structures and manipulation of instruments. Currently, carbon dioxide is the most frequently used gas for insufflation into the abdomen during laparoscopic abdominal surgery. However, carbon dioxide is associated with various changes in physiological parameters that affect the function of the heart or lungs (cardiopulmonary changes). Patients with poor heart or lung function may not tolerate these changes. Furthermore, carbon dioxide, which still stays in the abdomen after laparoscopic surgery, may cause postoperative pain. Thus, other gases, such as nitrous oxide and helium, have been suggested as alternatives to carbon dioxide for establishing pneumoperitoneum. This systematic review included seven trials with a total of 340 participants (the majority with low anaesthetic risk) comparing carbon dioxide pneumoperitoneum with nitrous oxide pneumoperitoneum (three trials, 196 participants) and carbon dioxide pneumoperitoneum with helium pneumoperitoneum (four trials, 144 participants). There were no trials comparing carbon dioxide pneumoperitoneum to any other gas pneumoperitoneum. All trials had a high risk of bias (suggesting the possibility of overestimating the benefits or underestimating the harms). There were no serious adverse events related to the use of either carbon dioxide or nitrous oxide pneumoperitoneum. Three serious adverse events (gas in the subcutaneous tissue) related to helium pneumoperitoneum were reported. Two of these trials showed that the pain scores were lower with nitrous oxide pneumoperitoneum than carbon dioxide pneumoperitoneum at various time points on the first post-operative day. There were no differences in the cardiopulmonary (heart and lung) complications, surgical complications, or cardiopulmonary changes between nitrous oxide and carbon dioxide pneumoperitoneum. The cardiopulmonary changes were fewer with helium pneumoperitoneum than carbon dioxide pneumoperitoneum. There were no differences in cardiopulmonary complications, surgical complications, or pain scores between helium and carbon dioxide pneumoperitoneum. In conclusion, nitrous oxide pneumoperitoneum during laparoscopic abdominal surgery appears to decrease post-operative pain in patients with low anaesthetic risk. Helium pneumoperitoneum decreases cardiopulmonary changes associated with laparoscopic abdominal surgery. However, this did not translate into any clinical benefit over carbon dioxide pneumoperitoneum. The safety of nitrous oxide and helium pneumoperitoneum has yet to be established.

The formation of carbon dioxide from the processing of carbon monoxide (CO) and molecular oxygen (18O2) via radiolysis is studied within the context of its formation in interstellar ices in quiescent clouds. With the help of isotopic labeling, we were able to ''trace'' the atoms and provide mechanistical information on how carbon monoxide is decomposed, and carbon dioxide is formed in interstellar ices. Here, we quantify the production of 18O3, O18O2, 18OO18O, C18O, CO2, 18OCO, and C18O2. In contrast to experiments using ultraviolet irradiation, we find that upon exposure to energetic electrons, isolated carbon monoxide molecules are able to undergo unimolecular decomposition to give suprathermal carbon (C) and oxygen (O) atoms. Molecular oxygen decomposes to two oxygen atoms. The free oxygen atoms can react with carbon monoxide via addition to form the carbon dioxide isotopomers as observed experimentally. This mechanism to form carbon dioxide is distinctly different to the one observed in pure carbon monoxide ices where electronically excited carbon monoxide reacts with a neighboring carbon monoxide molecule to form solely carbon dioxide and a carbon atom.

A Near Miss: A Nitrous Oxide-Carbon Dioxide Mix-up Despite Current Safety Standards

The dissociation of carbon dioxide and the reaction of carbon monoxide with oxygen caused by a high-energy (approx. 100 keV) electron beam in a typical carbon dioxide laser gas mixture has been observed. The variation of reaction rates with electron energy and current, interelectrode spacing, and gas composition has been studied. The rates of both processes suggest that the reactions are caused by unthermalized secondary electrons. The conditions were investigated under which the carbon monoxide oxidation reaction could be used to offset dissociation in a laser and thus prolong its sealed life. For a secondary to primary current ratio of one hundred this condition should be satisfied for any practical device. A sealed run was carried out which demonstrated that dissociation by secondary electrons could be offset by the oxidation of carbon monoxide by the primary electrons.

Inorganic Compounds of Carbon, Nitrogen, and Oxygen

Molybdenum para-Terphenyl Diphosphine Complexes

Humphry Davy

Nitrogenase is the only known enzyme to convert the triply bonded atmospheric dinitrogen (N2) to bioavailable ammonia (NH3) in an ambient environment, breaking one of the strongest chemical bond in nature in the process. Industrially, the Haber-Bosch process is also capable of reducing dinitrogen to ammonia, and is essential for worldwide food production 1,2. Due to the high temperatures and pressures required for the Haber-Bosch process (between 300-550oC and 15-25 MPa) and its requirement for molecular hydrogen, it has become paramount to scientifically investigate the biological processes of nitrogen fixation to ultimately develop more efficient methods to produce bioavailable ammonia. Nitrogenase utilizes two component proteins, the Fe-protein and the MoFe-protein, to reduce ammonia in an ATP-hydrolysis dependent and electron-intensive reaction. Besides the canonical dinitrogen reduction reaction, nitrogenase can reduce a variety of other substrates including: acetylene (C2H2), carbon dioxide (CO2), carbon monoxide (CO), carbonyl sulfide (COS), nitrous oxide (N2O), diazene (N2H2), and more 3-11. CO has long been of interest to the study of the mechanism of nitrogenase, owing to its isoelectronic identity to N2, and its potent inhibitor properties at well as its ability to serve as a weak substrate 12,13. Like CO, cyanide compounds (X-CN) are also of interest to the study of nitrogenase due to the isoelectronic nature of CN- to N2. However, cyanide compounds serve as particularly interesting spectroscopic and crystallographic tools, because X in X-CN can be substituted for more significant sulfur or selenium (Se). In this study, we investigate the substrate properties of SeCN-, with Se-incorporation into the active site FeMo-cofactor and concurrent reduction of SeCN- to methane (CH4). This study serves as yet another link between substrate reduction in nitrogenase. Part of this work describes the incorporation of Se into the cofactor as a vehicle for high-resolution study of nitrogenase under turnover using spectroscopy and crystallography, while another part describes a proposal for future work on the trapping of enzyme intermediates by fast-growing crystallography.

The depletion of carbon-based fossil fuels and the rise in atmospheric carbon dioxide concentration will force an inevitable change in the future global energy landscape. CO2 reduction presents the advantages of decreasing its atmospheric concentration and storing energy in chemical form in CO2 reduction products. With a predicted conversion to renewable energy such as solar or wind energy, energy storage will become a key process in the near future for buffering the fluctuating energy production. The objective of the present work was to study the efficiency towards CO2 reduction of different molecular catalysts. In particular, conducting experiments in high-pressure and supercritical conditions and observing the effect of CO2 pressure or concentration on the efficiency and selectivity of the reaction. As supercritical CO2 (scCO2) has poor solubilisation capabilities, experiments were conducted in biphasic systems or with addition of an organic co-solvent. To drive the reduction reaction of CO2, a catalyst is needed to overcome the kinetic limitations of the reaction, but an energy input is also necessary. Three different forms for this energy input were used in this work. In a first time a sacrificial product, decamethylferrocene (DMFc), was used to transfer electrons to CO2 in biphasic water/scCO2 systems. Complete oxidation of the DMFc was observed in presence of anion capable of transporting protons from water to the DMFc present in the supercritical phase. A photosensitization cycle was used to supply a water soluble catalyst, NI(II)Cyclam, in electron at the required potential to drive the reduction of CO2 into carbon monoxide in water/scCO2 system. The creation of the interface in the system appeared highly favourable to the efficiency of the catalyst. A second catalyst, a ruthenium polypyridyl carbonyl complex, was used for the photocatalytic reduction of CO2. Pressure had an important impact on the production of one of the two reduction product, carbon monoxide, while the production of formate was unaffected by CO2 pressure. As limitations in productivity in photocatalytic experiments were coming principally from the photosensitizer cycle or the sacrificial electron donor, photosensitizer was replaced by an electrode to provide the catalyst in electrons. Voltammetry in CO2-expanded liquids was described and determination of important parameters such as catalyst concentration and diffusion coefficient as a function of pressure was performed. Electrocatalytic reduction of CO2 by ruthenium and rhenium polypyridyl carbonyl complexes was studied in CO2-expanded liquids. The catalytic mechanisms were observed to be highly influenced by CO2 concentration.

Creation of variable concentrations of defects on TiO 2(110) using low-density electron beams

Universal “Plug and Play” Real-Time Entire Automotive Exhaust Effluents, Industry Vents and Flue Gas Emissions Liquefiers: The Game Changer Approach-Phase Two Category

Acute respiratory distress syndrome after an exothermic Baralyme-sevoflurane reaction.