Elimination Of Carbon Monoxide Research Articles

Carbon monoxide poisoning and phototherapy

Carbon monoxide (CO) poisoning is a leading cause of poison-related morbidity and mortality worldwide. By binding to hemoglobin and other heme-containing proteins, CO reduces oxygen delivery and produces tissue damage. Prompt treatment of CO-poisoned patients is necessary to prevent acute and long-term complications. Oxygen therapy is the only available treatment. Visible light has been shown to selectively dissociate CO from hemoglobin with high efficiency without affecting oxygen affinity. Pulmonary phototherapy has been shown to accelerate the rate of CO elimination in CO poisoned mice and rats when applied directly to the lungs or via intra-esophageal or intra-pleural optical fibers. The extracorporeal removal of CO using a membrane oxygenator with optimal characteristic for blood exposure to light has been shown to accelerate the rate of CO illumination in rats with or without lung injury and in pigs. The development of non-invasive techniques to apply pulmonary phototherapy and the development of a compact, highly efficient membrane oxygenator for the extracorporeal removal of CO in humans may provide a significant advance in the treatment of CO poisoning.

Carboxyhemoglobin half-life toxicokinetic profiles during and after normobaric oxygen therapy: On a swine model

Investigations on acute carbon monoxide (CO) poisoning struggle to highlight a relevant discriminant criterion related to CO poisoning severity for predicting complications, such as delayed neurological syndromes. In this context, it remains difficult to demonstrate the superiority of one method of oxygen (O2) administration over others or to identify the optimal duration of normobaric 100% oxygen (NBO) treatment. Myoglobin, as hemoglobin, are a potential binding site for CO, which could be a source of extravascular CO storage that impacts the severity of CO poisoning. It is not possible in routine clinical practice to estimate this potential extravascular CO storage. Indirect means of doing so that are available in the first few hours of poisoning could include, for example, the carboxyhemoglobin half-life (COHbt1/2), which seems to be influenced itself by the level and duration of CO exposure affecting this store of CO within the body. However, before the elimination of CO can be assessed, the COHbt1/2 toxicokinetic model must be confirmed: research still debates whether this model mono- or bi-compartmental. The second indirect mean could be the assessment of a potential COHb rebound after COHb has returned to 5% and NBO treatment has stopped. Moreover, a COHb rebound could be considered to justify the duration of NBO treatment. On an experimental swine model exposed to moderate CO poisoning (940 ppm for ±118 min until COHb reached 30%), we first confirm that the COHb half-life follows a bi-compartmental model. Secondly, we observe for the first time a slight COHb rebound when COHb returns to 5% and oxygen therapy is stopped. On the basis of these two toxicokinetic characteristics in favor of extravascular CO storage, we recommend that COHbt1/2 is considered using the bi-compartmental model in future clinical studies that compare treatment effectiveness as a potential severity criterion to homogenize cohorts of the same severity. Moreover, from a general toxicokinetic point of view, we confirm that a treatment lasting less than 6 hours appears to be insufficient for treating moderate CO poisoning.

Exhaust gas recirculation in a compression-ignition engine with nano coated Al2O3-TiO2 and ethanol fuel

Ethanol is a fuel that is sustainable, made from biomaterials, and oxygenated. It has the potential to lower the amount of particle emissions produced by diesel engines, as well as the amount of CO2 produced during its life cycle. Even though it was indicated by the exhaust gas recirculation (EGR) approach, the pistons, valves, and cylinder heads of the CI engine were coated in a ceramic compound composed of Al2O3 and TiO2. The exhaust gas recirculation (EGR) technology allows for the cooling and redirection of exhaust gas that has been removed from the cylinders of the exhaust system. Following the application of thermal coating to the piston, the performance of the engine's combustion system improved. The elimination of carbon monoxide, hydrocarbons, and smoke is a direct result of the addition of ethanol. According to the findings, there is a decrease in the amount of NOX emissions up to 11.72 g/kWh and 9.49 g/kWh produced by the cooled EGR engine.

Promoting mechanism of CuO on catalytic performance of CeFe catalyst for simultaneous removal of NOx and CO

Nitrogen oxides (NOx) and carbon monoxide (CO) coexisted in numerous industrial waste gases. And selective catalytic reduction of NOx with ammonia (NH3-SCR) and CO catalytic oxidation were considered as the effective technologies for simultaneous elimination of NOx and CO, respectively. However, an efficient bifunctional catalyst was crucial for achieving simultaneous removal of NOx and CO. Herein, we developed a series of Cu-modified CeFe catalysts for simultaneous removal of NOx and CO. The results demonstrated that 5Cu-CeFe catalyst presented the best catalytic performance, achieving approximately 81% NOx removal efficiency and nearly 99% CO conversion rate at 200 °C under a gas houely space velocity of 90,000 h−1. The XPS analysis demonstrated that copper oxides played a critical role in promoting the formation of Ce3+ and Oβ, thereby facilitating the NH3-SCR catalytic performance and CO catalytic oxidation. Moreover, the copper oxide modification of CeFe catalyst attained a trade-off between the surface acidity and redox ability, resulting in improving adsorption and activition capacity of the reactant gases. In situ DRIFTS experiments revealed that the NH3-SCR process primarily obeyed the Eley-Rideal (E-R) pathway over both CeFe and 5Cu-CeFe catalysts, while Langmuir-Hinshelwood (L-H) pathway hardly participated in NH3-SCR process. The presence of Cu+–CO species and surface lattice oxygen was crucial for CO oxidation, and both Mars-van Krevelen (M−K) and L-H pathways might be involved in the CO catalytic oxidation process over 5Cu-CeFe catalyst.

Optical, flow, and thermal analysis of a phototherapy extracorporeal membrane oxygenator for treating carbon monoxide poisoning.

Extracorporeal membrane oxygenators (ECMO) are currently utilized to mechanically ventilate blood when lung or lung and heart function are impaired, like in cases of acute respiratory distress syndrome (ARDS). ARDS can be caused by severe cases of carbon monoxide (CO) inhalation, which is the leading cause of poison-related deaths in the United States. ECMOs can be further optimized for severe CO inhalation using visible light to photo-dissociate CO from hemoglobin (Hb). In previous studies, we combined phototherapy with an ECMO to design a photo-ECMO device, which significantly increased CO elimination and improved survival in CO-poisoned animal models using light at 460, 523, and 620 nm wavelengths. Light at 620 nm was the most effective in removing CO. The aim of this study is to analyze the light propagation at 460, 523, and 620 nm wavelengths and the 3D blood flow and heating distribution within the photo-ECMO device that increased CO elimination in CO-poisoned animal models. Light propagation, blood flow dynamics, and heat diffusion were modeled using the Monte Carlo method and the laminar Navier-Stokes and heat diffusion equations, respectively. Light at 620 nm propagated through the device blood compartment (4 mm), while light at 460 and 523 nm only penetrated 48% to 50% (~2 mm). The blood flow velocity in the blood compartment varied with regions of high (5 mm/s) and low (1 mm/s) velocity, including stagnant flow. The blood temperatures at the device outlet for 460, 523, and 620 nm wavelengths were approximately 26.7°C, 27.4°C, and 20°C, respectively. However, the maximum temperatures within the blood treatment compartment rose to approximately 71°C, 77°C, and 21°C, respectively. As the extent of light propagation correlates with efficiency in photodissociation, the light at 620 nm is the optimal wavelength for removing CO from Hb while maintaining blood temperatures below thermal damage. Measuring the inlet and outlet blood temperatures is not enough to avoid unintentional thermal damage by light irradiation. Computational models can help eliminate risks of excessive heating and improve device development by analyzing design modifications that improve blood flow, like suppressing stagnant flow, further increasing the rate of CO elimination.

Environmental impact of waste plastic pyrolysis oil on insulated piston diesel engine with methoxyethyl acetate additive

The energy recovery from waste plastics as a prospective fuel source helps to overcome the issues of waste plastic management and the growing fuel shortage. In this article, High-Density Polyethylene (HDPE) plastics are used to convert into waste plastic pyrolysis oil (WPPO) through the pyrolysis process. An experimental investigation is carried out to evaluate the effectiveness of WPPO in a Thermal Barrier Coated piston engine (TBC) with an oxygenated additive of Methoxyethyl acetate (MEA). The incremental ratio of WPPO to pure diesel with the addition MEA and its performance, combustion, and emission characteristics are studied in a direct injection single-cylinder low heat rejection diesel engine. MEA and the coated piston resulted in improved performance of WPPO. Brake-specific fuel consumption is reduced by up to 9% under various load situations. D70W20MEA10 shows carbon monoxide elimination of up to 15% under various load conditions and a hydrocarbon reduction of up to 16%. At half load, D70W20MEA10 produces about 3% less HSU of smoke.

Extracorporeal Hyperoxygenation Therapy (EHT) for Carbon Monoxide Poisoning: In-Vitro Proof of Principle.

Carbon monoxide (CO) poisoning is the leading cause of poisoning-related deaths globally. The currently available therapy options are normobaric oxygen (NBO) and hyperbaric oxygen (HBO). While NBO lacks in efficacy, HBO is not available in all areas and countries. We present a novel method, extracorporeal hyperoxygenation therapy (EHT), for the treatment of CO poisoning that eliminates the CO by treating blood extracorporeally at elevated oxygen partial pressure. In this study, we proof the principle of the method in vitro using procine blood: Firstly, we investigated the difference in the CO elimination of a hollow fibre membrane oxygenator and a specifically designed batch oxygenator based on the bubble oxygenator principle at elevated pressures (1, 3 bar). Secondly, the batch oxygenator was redesigned and tested for a broader range of pressures (1, 3, 5, 7 bar) and temperatures (23, 30, 37 °C). So far, the shortest measured carboxyhemoglobin half-life in the blood was 21.32 min. In conclusion, EHT has the potential to provide an easily available and effective method for the treatment of CO poisoning.

Hyperbaric phototherapy augments blood carbon monoxide removal.

Carbon monoxide (CO) poisoning is responsible for nearly 50,000 emergency department visits and 1200 deaths per year. Compared to oxygen, CO has a 250-fold higher affinity for hemoglobin (Hb), resulting in the displacement of oxygen from Hb and impaired oxygen delivery to tissues. Optimal treatment of CO-poisoned patients involves the administration of hyperbaric 100% oxygen to remove CO from Hb and to restore oxygen delivery. However, hyperbaric chambers are not widely available and this treatment requires transporting a CO-poisoned patient to a specialized center, which can result in delayed treatment. Visible light is known to dissociate CO from carboxyhemoglobin (COHb). In a previous study, we showed that a system composed of six photo-extracorporeal membrane oxygenation (ECMO) devices efficiently removes CO from a large animal with CO poisoning. In this study, we tested the hypothesis that the application of hyperbaric oxygen to the photo-ECMO device would further increase the rate of CO elimination. We developed a hyperbaric photo-ECMO device and assessed the ability of the device to remove CO from CO-poisoned human blood. We combined four devices into a "hyperbaric photo-ECMO system" and compared its ability to remove CO to our previously described photo-ECMO system, which was composed of six devices ventilated with normobaric oxygen. Under normobaric conditions, an increase in oxygen concentration from 21% to 100% significantly increased CO elimination from CO-poisoned blood after a single pass through the device. Increased oxygen pressure within the photo-ECMO device was associated with higher exiting blood PO2 levels and increased CO elimination. The system of four hyperbaric photo-ECMO devices removed CO from 1 L of CO-poisoned blood as quickly as the original, normobaric photo-ECMO system composed of six devices. This study demonstrates the feasibility and efficacy of using a hyperbaric photo-ECMO system to increase the rate of CO elimination from CO-poisoned blood. This technology could provide a simple portable emergency device and facilitate immediate treatment of CO-poisoned patients at or near the site of injury.

Empirical validation and simulation of existing CO exposure models with hospital pulmonary function datasets

BACKGROUND AND AIM: Carbon monoxide (CO) poisoning is a critical global public health issue. Several CO exposure models were built to predict the kinetics of CO uptake and elimination in CO poisoning but based on a limited data set. Therefore, the aim of the study is to extend the CO exposure models to people with a wider range of several characteristic, such as age, sex, height, weight, smoking status. To address this, we tested relationships between these demographic factors, pulmonary function (DLCO), and the rate of CO uptake and CO elimination. METHODS: We collected pulmonary function datasets from Tri-Service General Hospital in Taiwan (N=1,943 Asian patients), and Royal Berkshire Hospital in the UK (N=691 Caucasian patients). In these data we obtained the DLCO by demographics. Then we used the observed DLCO values within existing CO models (Coburn-Forster-Kane (CFK) models) to predict the rate of CO uptake and elimination for different individuals in different scenarios. RESULTS:We found that males had a higher value of DLCO than females, and DLCO was positively associated with height (β=0.122, p0.05) and weight (β=0.104, p0.05), and negatively associated with age (β=-0.186, p0.05). Then, we used estimated DLCO from data gathered from pulmonary function datasets to update established CFK models. The results showed that for example: when exposed to 10,000 ppm for 5 min, there is a higher peak of CO ppm in a younger male compared to an older male (COHb (%): 20.8 vs. 19.5). CONCLUSIONS:In conclusion, the updated model has the advantage of being able to predict CO uptake and elimination for a wider range of individuals compared to previous CFK models, factoring in their age, sex, height, weight, ethnic group, and smoking status. This could help estimate past CO exposure, and help medical staff recognize CO exposure and design optimal treatments for CO exposure victims. KEYWORDS: Air pollution, Biomarkers of exposure, Epidemiology, Exposures, Exposure assessment, Toxicology

Veno-venous extracorporeal blood phototherapy increases the rate of carbon monoxide (CO) elimination in CO-poisoned pigs.

Carbon monoxide (CO) inhalation is the leading cause of poison-related deaths in the United States. CO binds to hemoglobin (Hb), displaces oxygen, and reduces oxygen delivery to tissues. The optimal treatment for CO poisoning in patients with normal lung function is the administration of hyperbaric oxygen (HBO). However, hyperbaric chambers are only available in medical centers with specialized equipment, resulting in delayed therapy. Visible light dissociates CO from Hb with minimal effect on oxygen binding. In a previous study, we combined a membrane oxygenator with phototherapy at 623 nm to produce a "mini" photo-ECMO (extracorporeal membrane oxygenation) device, which improved CO elimination and survival in CO-poisoned rats. The objective of this study was to develop a larger photo-ECMO device ("maxi" photo-ECMO) and to test its ability to remove CO from a porcine model of CO poisoning. The "maxi" photo-ECMO device and the photo-ECMO system (six maxi photo-ECMO devices assembled in parallel), were tested in an in vitro circuit of CO poisoning. To assess the ability of the photo-ECMO device and the photo-ECMO system to remove CO from CO-poisoned blood in vitro, the half-life of COHb (COHb-t1/2 ), as well as the percent COHb reduction in a single blood pass through the device, were assessed. In the in vivo studies, we assessed the COHb-t1/2 in a CO-poisoned pig under three conditions: (1) While the pig breathed 100% oxygen through the endotracheal tube; (2) while the pig was connected to the photo-ECMO system with no light exposure; and (3) while the pig was connected to the photo-ECMO system, which was exposed to red light. The photo-ECMO device was able to fully oxygenate the blood after a single pass through the device. Compared to ventilation with 100% oxygen alone, illumination with red light together with 100% oxygen was twice as efficient in removing CO from blood. Changes in gas flow rates did not alter CO elimination in one pass through the device. Increases in irradiance up to 214 mW/cm2 were associated with an increased rate of CO elimination. The photo-ECMO device was effective over a range of blood flow rates and with higher blood flow rates, more CO was eliminated. A photo-ECMO system composed of six photo-ECMO devices removed CO faster from CO-poisoned blood than a single photo-ECMO device. In a CO-poisoned pig, the photo-ECMO system increased the rate of CO elimination without significantly increasing the animal's body temperature or causing hemodynamic instability. In this study, we developed a photo-ECMO system and demonstrated its ability to remove CO from CO-poisoned 45-kg pigs. Technical modifications of the photo-ECMO system, including the development of a compact, portable device, will permit treatment of patients with CO poisoning at the scene of their poisoning, during transit to a local emergency room, and in hospitals that lack HBO facilities.

Catalytic Elimination of Carbon Monoxide, Ethyl Acetate, and Toluene over the Ni/OMS-2 Catalysts

The Ni-loaded cryptomelane-type manganese oxide octahedral molecular sieve (OMS-2) catalysts (xNi/OMS-2: x = 1, 3, 5, and 10 wt%) were prepared by a pre-incorporation method. Physicochemical properties of the as-synthesized materials were characterized by means of various techniques, and their catalytic activities for CO, ethyl acetate, and toluene oxidation were evaluated.The loading of Ni played an important role in improving physicochemical propertiesof OMS-2. Among all of the samples, 5Ni/OMS-2 exhibited the best catalytic activity, with the T90 being 155 °C for CO oxidation at a space velocity (SV) of 60,000 mL/(g·h), 225°C for ethyl acetate oxidation at an SV of 240,000 mL/(g·h), and 300 °C for toluene oxidation at an SV of 240,000 mL/(g·h), which was due to its high Mn3+ content and Oads concentration, good low-temperature reducibility and lattice oxygen mobility, and strong interaction between the Ni species and the OMS-2 support. In addition, catalytic mechanisms of the oxidation of three pollutants over 5Ni/OMS-2 were also studied. The oxidation of CO, ethyl acetate, and toluene over the catalysts took place first via the activated adsorption, then intermediates formation, and finally complete conversion of the formed intermediates to CO2 and H2O.

Six degrees head-down tilt bed rest caused low-grade hemolysis: a prospective randomized clinical trial

This study aimed to measure hemolysis before, during and after 60 days of the ground-based spaceflight analog bed rest and the effect of a nutritional intervention through a prospective randomized clinical trial. Twenty male participants were hospitalized for 88 days comprised of 14 days of ambulatory baseline, 60 days of 6° head-down tilt bed rest and 14 days of reambulation. Ten participants each received a control diet or daily polyphenol associated with omega-3, vitamin E, and selenium supplements. The primary outcome was endogenous carbon monoxide (CO) elimination measured by gas chromatography. Hemolysis was also measured with serial bilirubin, iron, transferrin saturation blood levels and serial 3-day stool collections were used to measure urobilinoid excretion using photometry. Total hemoglobin mass (tHb) was measured using CO-rebreathing. CO elimination increased after 5, 11, 30, and 57 days of bed rest: +289 ppb (95% CI 101–477 ppb; p = 0.004), +253 ppb (78–427 ppb; p = 0.007), +193 ppb (89–298 ppb; p = 0.001) and +858 ppb (670–1046 ppb; p < 0.000), respectively, compared to baseline. Bilirubin increased after 20 and 49 days of bed rest +0.8 mg/l (p = 0.013) and +1.1 mg/l (p = 0.012), respectively; and iron increased after 20 days of bed rest +10.5 µg/dl (p = 0.032). The nutritional intervention did not change CO elimination. THb was lower after 60 days of bed rest −0.9 g/kg (p = 0.001). Bed rest enhanced hemolysis as measured through all three by-products of heme oxygenase. Ongoing enhanced hemolysis over 60 days contributed to a 10% decrease in tHb mass. Modulation of red blood cell control towards increased hemolysis may be an important mechanism causing anemia in astronauts.

Modification of CO models with factors related to CO uptake and elimination and comparison of the simulations with experimental observations

Background/Aim: Carbon monoxide (CO) poisoning is an important public health issue globally. Mathematical models for predicting the uptake and elimination of CO could help assess exposure scenarios. We aim to study CO kinetics from pulmonary function test data and provide a predicted model of DLCO. Then, we investigate a simplified version of the compartment model for CO by comparing its predictions against observed data. Methods: We collected 419 patients’ data from June 2017 to May 2018 from Tri-Service General Hospital (TSGH) in Taipei and analysed demographic variables and CO diffusion capacity (DLCO). After obtaining the predicted model for DLCO, we used the predicted model to input new values for CO models, including the Coburn, Forster and Kane (CFK) model (Coburn et al. 1965) and the modified CFK model (Gosselin et al. 2009). Then, using Excel and Python to simulate the CO uptake and elimination data from models, and a comparison was made with data from CO-rebreathing and exhaled CO experiments. Results and Conclusions: The predictive model for DLCO was -3.856-0.119*age(yr) +0.133*height(cm)+0.125*weight(kg) for female and -1.321-.210*age(yr)+0.165*height(cm) +0.102*weight(kg) for male. We compared the simulated data with measured COHb% data in blood and exhaled CO at 30 min after CO exposure. For the CO-rebreathing experiment, the results showed that the COHb% predicted data from the CFK model (Mean±SE: 6.01±0.51%) and the CFK model with new input (5.43±0.51%) have no significant difference with the observations (6.41±0.42%). For the exhaled CO experiment, the measured COHb% data was 2.29±0.11% and the predicted data from CFK model was lower at 1.77±0.01%; the CFK model with new input was closer at 2.32±0.07%. The Scheffe test shows the measured data has a significant difference with the predicted data from CFK model. The next step in the research will simulate the CFK model used for different scenarios.

Nickel Tetracarbonyl as Starting Material for the Synthesis of NHC‐stabilized Nickel(II) Allyl Complexes

A novel, useful in situ synthesis for NHC nickel allyl halide complexes [Ni(NHC)(η3‐allyl)(X)] starting from [Ni(CO)4], NHC and allyl halides is presented. The reaction of [Ni(CO)4] with (i) one equivalent of the corresponding NHC and (ii) with an excess of the corresponding allyl chloride at room temperature leads with elimination of carbon monoxide to complexes of the type [Ni(NHC)(η3‐allyl)(X)]. This approach was used to synthesize the complexes [Ni(tBu2Im)(η3‐H2C‐C(Me)‐CH2)(Cl)] (2), [Ni(iPr2ImMe)(η3‐H2C‐C(Me)‐CH2)(Cl)] (3), [Ni(iPr2Im)(η3‐H2C‐C(Me)‐CH2)(Cl)] (4), [Ni(iPr2Im)(η3‐H2C‐C(H)‐C(Me)2)(Br)] (5), [Ni(Me2ImMe)(η3‐H2C‐C(Me)‐CH2)(Cl)] (6), and [Ni(EtiPrImMe)(η3‐H2C‐C(Me)‐CH2)(Cl)] (7). The complexes 1 to 7 were characterized using NMR and IR spectroscopy and elemental analysis, and the molecular structures are provided for 2 and 7. The allyl nickel complexes 1–7 are stereochemically non‐rigid in solution due to (i) NHC rotation about the nickel‐carbon bond, (ii) allyl rotation about the Ni–η3‐allyl axis and (iii) π–σ–π allyl isomerization processes. The allyl halide complexes can be methylated as was demonstrated by the methylation of a number of the complexes [Ni(NHC)(η3‐allyl)(X)] with methylmagnesium chloride or methyllithium, which led to isolation of the complexes [Ni(Me2Im)(η3‐H2C‐C(Me)‐CH2)(Me)] (8), [Ni(tBu2Im)(η3‐H2C‐C(Me)‐CH2)(Me)] (9), [Ni(iPr2ImMe)(η3‐H2C‐C(Me)‐CH2)(Me)] (10), [Ni(iPr2Im)(η3‐H2C‐C(Me)‐CH2)(Me)] (11), [Ni(iPr2Im)(η3‐H2C‐C(H)‐C(Me)2)(Me)] (12), and [Ni(EtiPrImMe)(η3‐H2C‐C(Me)‐CH2)(Me)] (13). These complexes were fully characterized including X‐ray molecular structures for 10 and 11.

Measuring Human Hemolysis Clinically and in Extreme Environments Using Endogenous Carbon Monoxide Elimination.

The measure of hemolysis in humans is clinically important. Here we describe methods using a gas chromatograph equipped with a reduction gas detector to detect the human analyte carbon monoxide (CO) that were developed for the extreme environment of the International Space Station. These methods can be adapted to in-hospital use for clinical care with characteristics that may surpass existing measures of hemolysis. We demonstrate improved performance over previous-generation methods in terms of reproducibility, accuracy, control for physical and intervening factors to quantitatively assess hemolysis rates at unprecedented levels. The presented measure of hemolysis using CO elimination is based on a different physiological approach that can complement and augment existing detection tools. In addition to their suitability for extreme environments, the methods present distinctive advantages over existing markers for the diagnosis, monitoring and response to treatment of hemolytic anemia. These methods have the potential to fulfill a wide range of research and clinical applications.

A Palladium-Catalyzed Cascade C-C Activation of Cyclopropenone and Carbonylative Amination: Easy Access to Highly Functionalized Maleimide Derivatives.

We describe herein the first report on palladium-catalyzed C-C bond activation of cyclopropenone and concomitant carbonylative amination to produce maleimides. The interesting aspect of this reaction is that the sacrificial elimination of carbon monoxide from the substrate is efficiently recaptured by one of the intermediates in the catalytic cycle for the formation of maleimides. 18O isotopic studies confirmed that the source of carbon monoxide is from cyclopropenone.

Factors Contributing to CO Uptake and Elimination in the Body: A Critical Review.

Background: Carbon monoxide (CO) poisoning is an important public health issue around the world. Research indicates that many factors may be related to the rate of CO uptake and elimination in the human body. However, some factors related to CO uptake and elimination are considered controversial. Relatively little attention has been devoted to review and synthesis of factors affecting CO uptake and elimination. Purpose: This paper provides a critical scoping review of the factors and divides them into four aspects, including environmental, demographic, physiological and treatment factors. Methods: We searched the scientific databases for research that has proposed a mathematical equation as a synthesis of quantities related to CO poisoning, CO elimination, CO uptake, CO half-life, CO uptake and elimination and their relationships. After excluding the studies that did not meet the study criteria, there were 39 studies included in the review and the search was completed before 16 December 2019. Results and conclusion: This review discusses most of the factors that impact the rate of CO uptake and elimination. Several factors may be related to CO uptake and elimination, such as CO concentration, the duration of exposure to CO, age, sex, exercise, minute ventilation, alveolar ventilation, total haemoglobin mass and different treatments for CO poisoning. Although some potential factors were not included in the review, the findings are useful by presenting an overview for discussing factors affecting CO uptake and elimination and provide a starting point for further study regarding strategies for CO poisoning and the environmental standard of CO.

Phototherapy and extracorporeal membrane oxygenation facilitate removal of carbon monoxide in rats.

Inhaled carbon monoxide (CO) displaces oxygen from hemoglobin, reducing the capacity of blood to carry oxygen. Current treatments for CO-poisoned patients involve administration of 100% oxygen; however, when CO poisoning is associated with acute lung injury secondary to smoke inhalation, burns, or trauma, breathing 100% oxygen may be ineffective. Visible light dissociates CO from hemoglobin. We hypothesized that the exposure of blood to visible light while passing through a membrane oxygenator would increase the rate of CO elimination in vivo. We developed a membrane oxygenator with optimal characteristics to facilitate exposure of blood to visible light and tested the device in a rat model of CO poisoning, with or without concomitant lung injury. Compared to ventilation with 100% oxygen, the addition of extracorporeal removal of CO with phototherapy (ECCOR-P) doubled the rate of CO elimination in CO-poisoned rats with normal lungs. In CO-poisoned rats with acute lung injury, treatment with ECCOR-P increased the rate of CO removal by threefold compared to ventilation with 100% oxygen alone and was associated with improved survival. Further development and adaptation of this extracorporeal CO photo-removal device for clinical use may provide additional benefits for CO-poisoned patients, especially for those with concurrent acute lung injury.

Preparation of mesoporous nanocrystalline CuO–ZnO–Al2O3 catalysts for the H2 purification using catalytic preferential oxidation of CO (CO-PROX)

In this article, CuO–ZnO–Al2O3 catalysts with various copper contents were synthesized by a co-precipitation method and employed for the elimination of carbon monoxide from a mixture of 97% H2, 1% CO and 2% O2 at atmospheric pressure via carbon monoxide preferential oxidation (CO-PROX). The influence of the copper and zinc contents on the physicochemical characteristics and catalytic performance was investigated. The prepared samples were characterized using the N2 adsorption-desorption (BET), X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM and SEM) and temperature programmed reduction (TPR) techniques. The increment in CuO loading improved the activity of CuO–ZnO–Al2O3 catalysts for CO oxidation reaction. Among the prepared catalysts, the 50%CuO-3% ZnO-47% Al2O3 catalyst calcined at 400 °C with a BET area of 82.3 m2/g exhibited the best activity with a CO conversion of 88.9% at 125 °C. The effects of the presence of CO2 and H2O in the reaction feed stream and gas hourly space velocity (GHSV) were also studied.

A synthesis of N-(1H-pyrazol-5-yl)-1,3,4-thiadiazol-2(3H)-imines from nitrile imines and Erlenmeyer thioazlactones.

Erlenmeyer thioazlactones are reacted with hydrazonoyl chlorides in the presence of Et3N to afford functionalized N-(1H-pyrazol-5-yl)-1,3,4-thiadiazol-2(3H)-imines in excellent yields. This strategy is based on a domino double 1,3-dipolar cycloaddition reaction of nitrile imines to Erlenmeyer thioazlactones, followed by the elimination of carbon monoxide and phenylmethanthiol from the initially formed cycloadducts. This method provides fast access to a variety of structurally diverse N-(1H-pyrazol-5-yl)-1,3,4-thiadiazol-2(3H)-imines. The structure of a typical product was established by X-ray crystallography.