Humidified CO2 Research Articles

Alcohol Production from Carbon Dioxide: Methanol as a Fuel and Chemical Feedstock

Summary Production of renewable alcohols from air, water, and sunlight present an avenue to utilize captured carbon dioxide for the production of basic chemicals and store renewable energy in the chemical bonds of liquid fuels. Of the technologies that utilize CO2 directly, CO2 electrolysis, as well as CO2 hydrogenation coupled with H2O electrolysis, have the benefit of requiring only CO2, H2O, and renewable electricity as inputs with O2 as a sole byproduct. Among alcohols, renewable methanol has seen the most development and analysis in the chemical industry because it is currently a syngas-derived product that could be adapted for direct CO2 utilization. In this perspective, we compare renewably powered CO2 electrolysis and CO2 hydrogenation with the incumbent methanol production method from syngas from a cost and CO2 life cycle perspective by analyzing recent literature to identify the research goals that enable further scale-up. Survey of the industry shows that CO2 hydrogenation is among the closest CO2 utilization technologies to large-scale deployment. We further discuss these CO2 hydrogenation systems and the catalysts that drive them, with recommendations to drive further development and scale-up.

Membrane-Based Zero Gap CO2 Electrolyzer with Au Cathode Prepared By Electrodeposition

Electrochemical CO2 conversion has been recognized as a promising technology that can overcome the global warming. Also, the production of useful fuels (e.g. CO, HCOOH, CH4, CH3OH and C2H4) is capable via electrochemical reduction of CO2. It was demonstrated that at least 200 mA cm–2 of partial current density should be required for commercial operation. However, in conventional aqueous system, the CO2 electroreduction was limited to 35 mA cm–2 of current density due to low CO2 solubility into the electrolyte. Furthermore, the diffusion length of CO2 from bulk to catalyst is much longer in H-type cell system causing prevent easy supply of CO2. To overcome these problems, a single cell based on a membrane electrode assembly (MEA) with zero gap between the electrodes was introduced to facilitate CO2 mass transfer to the catalyst surface.In this study, we investigate the MEA-based CO2 electrolyzer with anion exchange membrane. The electrodeposited Au on gas diffusion electrode (GDL), which exhibits the high CO production selectivity in CO2 electroreduction, was directly used as a cathode of CO2 electrolyzer. The humidified CO2 gas is supplied into cathode to promote the CO2 mass transfer to the catalysts-membrane interfaces. Furthermore, the content of polytetrafluoroethylene on GDL was controlled in order to prevent the product crossover between compartments that is feasible to exhibit stable performance. Compared to conventional H-type cell system, the 2-order magnitude improvement of partial current density was shown in MEA-based zero gap CO2 electrolyzer owing to low ohmic resistance and facile CO2 mass transfer.

Effects of Warmed and Humidified CO2 Surgical Site Insufflation in a Novel Experimental Model of Magnetic Compression Colonic Anastomosis.

Background. Pneumoperitoneum insufflation with warmed and humidified carbon dioxide (WH-CO2) can prevent heat loss and increase tissue oxygenation. We evaluated the impact of localized WH-CO2 insufflation on the anastomotic healing process. Methods. Sixty male Wistar rats were randomized: Group 1 (control, n = 12), Group 2 (cold and dry CO2, CD-CO2, n = 24), and Group 3 (WH-CO2, n = 24). A magnetic compression side-to-side colonic anastomosis was performed under 60-minute local abdominal CO2 flow insufflation. Animal temperature was recorded. IL-1, IL-6, and CRP levels were assessed before and after insufflation and on postoperative day (POD) 7 and POD 10. Endoscopic follow-up was performed on POD 7 and POD 10. A burst pressure (BP) test of the specimen was performed on POD 10, and histopathological analysis was then performed. Metabolomics of the anastomotic site was determined. Results. Seven rats (5 CD-CO2 group, 1 WH-CO2 group, and 1 control group) died during the survival period. Necropsies revealed intestinal occlusions (n = 2). One additional rat from the CD-CO2 group was sacrificed on POD 7 due to intestinal perforation. The postoperative course was uneventful in the remaining cases. There was no difference in BP among the groups. Thermal monitoring confirmed that WH-CO2 insufflation was effective to reduce heat loss. IL-1 levels were statistically and significantly lower on POD 10 in the WH-CO2 group than the CD-CO2 group but not lower than the control group. CRP levels, histopathology, and metabolomics did not show any difference between the 3 groups. Conclusions. WH-CO2 was effective to preserve core temperature. However, it did not improve anastomotic healing.

Fetoscopic insufflation modeled in the extrauterine environment for neonatal development (EXTEND): Fetoscopic insufflation is safe for the fetus

BackgroundMinimally invasive fetal surgery, or fetoscopy, is an alternative to open fetal surgery to repair common birth defects like myelomeningocele. Although this hysterotomy-sparing approach reduces maternal morbidity, the effects of in utero insufflation on the fetus are poorly understood. Our purpose was to determine the optimal fetal insufflation conditions. MethodsFetal sheep at gestational age 104 to 107 days were studied under insufflation conditions in utero and ex utero. The ex utero fetuses were cannulated via their umbilical vessels into a support device, the EXTra-uterine Environment for Neonatal Development (EXTEND). EXTEND fetuses were exposed to four different insufflation conditions for four hours: untreated carbon dioxide (CO2) (n=5), warm humidified (whCO2) (n=4), whCO2 with the umbilical cord exposed (n=3), and whCO2 without amniotic fluid (skin and cord exposed) (n=3). ResultsIn utero insufflation led to significant increases in fetal CO2 and reductions in fetal pH. Ex utero insufflation with whCO2 did not lead to changes in fetal blood gas measurements or cerebral perfusion parameters. Insufflation with whCO2 with an exposed umbilical cord led to reduced umbilical blood flow. ConclusionsInsufflation with warm humidified CO2 with an amniotic fluid covered umbilical cord is well tolerated by the fetus without significant changes in hemodynamics or cerebral perfusion parameters. Type of studyBasic science Level of evidenceN/A

The Pathogenesis and Prevention of Port-Site Metastasis in Gynecologic Oncology.

Port-site metastasis (PSM) is a specific and challenging complication of laparoscopic gynecologic oncologic procedures. Research has demonstrated that PSM is associated with significant morbidity and poor outcome. The exact pathogenesis of PSM in gynecologic patients is not clear. Several preventive measures of PSM have been addressed in the relevant literature, and novel approaches to prevent this uncommon complication keep emerging. In this review, we summarized the potential mechanisms of PSM and discuss the controversies and merits of proposed preventive measures of PSM in gynecologic oncology. We undertook a literature search using the Medline database to identify studies on the pathogenesis and prevention of laparoscopic PSM. Hypotheses of PSM pathogeneses center on the immune response, pneumoperitoneum, wound contamination, and surgical method. Cogent evidence of effective prevention of PSM after laparoscopic surgery is lacking. Traditional preventive actions such as irrigation and tumor manipulation should be taken individually. Insufflation of hyperthermic CO2 and humidified CO2 leads to a better outcome in patients with a malignant tumor who undergo a laparoscopic procedure compared with normal CO2 pneumoperitoneum. Port-site resection shows no advantage in survival and results in more wound events. PSM prevention plays a crucial part in the overall care of patients with gynecologic malignancies who undergo laparoscopic procedures.

Direct Water Injection in Catholyte‐Free Zero‐Gap Carbon Dioxide Electrolyzers

AbstractA zero‐gap flow electrolyzer with a tin‐coated gas diffusion electrode as the cathode was used to convert humidified gaseous CO2 to formate. The influence of humidification, flow pattern and the type of membrane on the faradaic efficiency (FE), product concentration, and salt precipitation were investigated. We demonstrated that water management in the gas diffusion electrode was crucial to avoid flooding and (bi)carbonate precipitation, to uphold a high FE and formate concentration. Direct water injection was validated as a novel approach for water management. At 100 mA/cm2, direct water injection in combination with an interdigitated flow channel resulted in a FE of 80 % and a formate concentration of 65.4+/−0.3 g/l without salt precipitation for a prolonged CO2 electrolysis of 1 h. The use of bipolar membranes in the zero‐gap configuration mainly produced hydrogen. These results are important for the design of commercial scale CO2 electrolyzers.

The effect of humidified warmed CO2 during open colorectal surgery on body temperature and postoperative pain: a randomized controlled trial.

IntroductionOpen abdominal surgery exposes the intestine to negative ventilation (20°C, 0-5% RH), which along with the large surface area of peritoneum has the potential to cause loss of body heat. This study examined whether the warmed, humidified CO2 (WHCO2) can reduce heat loss and reduce postoperative pain.MethodsA randomized controlled trial was performed at a tertiary colorectal unit (Concord Repatriation General Hospital, The University of Sydney, Australia). The study group received WHCO2 at a rate of 10L/min. The control group did not receive any insufflation during the operation. Patients were over 18 years of age undergoing elective open colorectal operations. Core body temperature measurement was made every 15 minutely with a trans-oesophageal probe. Postoperative pain was assessed via: (1) duration of use of patient controlled analgesia (PCA), (2) total oral morphine equivalent daily dose (oral MEDD).Results39 Patients were recruited in the study, with 20 patients receiving WHCO2. There was no difference in the core body temperature between the WHCO2 and the Control group (36.1 vs. 35.9°C, p=0.35). There was no difference in the % of the operating time where core body temperature dropped below the lower limit of normal of 35.8°C (28.4% vs 35.8%, p=0.51), or to the level of hypothermia of 35°C (7.7% vs. 13.4%, p=0.50). No difference in postoperative PCA duration, as well as MEDD, were noted between the CO2 group and control group.ConclusionWHCO2 had no effect on core body temperature during open colorectal surgery and the postoperative pain experienced.

Fast and Stable Proton Conduction in Heavily Scandium‐Doped Polycrystalline Barium Zirconate at Intermediate Temperatures

AbstractThe environmental benefits of fuel cells and electrolyzers have become increasingly recognized in recent years. Fuel cells and electrolyzers that can operate at intermediate temperatures (300–450 °C) require, in principle, neither the precious metal catalysts that are typically used in polymer‐electrolyte‐membrane systems nor the costly heat‐resistant alloys used in balance‐of‐plant components of high‐temperature solid oxide electrochemical cells. These devices require an electrolyte with high ionic conductivity, typically more than 0.01 S cm−1, and high chemical stability. To date, however, high ionic conductivities have been found in chemically unstable materials such as CsH2PO4, In‐doped SnP2O7, BaH2, and LaH3−2xOx. Here, fast and stable proton conduction in 60‐at% Sc‐doped barium zirconate polycrystal, with a total conductivity of 0.01 S cm−1 at 396 °C for 200 h is demonstrated. Heavy doping of Sc in barium zirconate simultaneously enhances the proton concentration, bulk proton diffusivity, specific grain boundary conductivity, and grain growth. An accelerated stability test under a highly concentrated and humidified CO2 stream using in situ X‐ray diffraction shows that the perovskite phase is stable over 240 h at 400 °C under 0.98 atm of CO2. These results show great promises as an electrolyte in solid‐state electrochemical devices operated at intermediate temperatures.

N-Doped Nanoporous Carbon Scaffold As an Electrocatalyst for CO2 Reduction

The rising level of CO2 in the atmosphere poses a major threat to our global climate [1]. Renewable energy are promising alternatives but the utilization of renewable energy is challenging because of its intermittency. The key solution is to develop an energy storage system that can store energy and then release it as needed. CO2 reduction reaction (CO2RR) uses abundant CO2 present in the atmosphere and renewable energy as the input power. Therefore, increasing interest has been focused on electrochemical routes to transform CO2 into useful products. However, the reduction of CO2 is thermodynamically and kinetically unfavorable. To overcome the energy barrier of CO2RR, the development of high efficiency and high selectivity catalysts is a key goal of CO2RR research.Metallic catalysts have attracted much attention for CO2RR and have achieved some successes. However, most metallic catalysts exhibit large CO2RR overpotentials and insufficient selectivity. Also, the high price of noble metals is a key obstacle to scale-up and commercialization of these materials for CO2RR.Carbon is a very promising candidate to advance CO2RR due to its high specific surface areas and good conductivity. However, carbon atoms are electrically neutral and therefore it is difficult to activate the CO2 molecules and adsorb the intermediate. Therefore, it is necessary to develop novel carbon catalysts to enhance their catalytic activity for CO2RR. Nitrogen is the most commonly used carbon doping atom due to its high electronegativity, which leads to polarization of the adjacent carbon atoms, thus enhancing the electronic/ionic conductivity [2]. Many carbon materials, such as carbon nanotubes and graphene, have been doped with N and investigated as CO2RR catalysts [3][4], with some N-doped materials exhibiting a 85% Faradaic efficiency towards CO production[5].In this work, a nitrogen-doped templated nanoporous carbon scaffold (N-doped NCS) was investigated as a catalyst material for electrochemical CO2 reduction. The NCS is a novel, templated, binder-free, self-supported, fully tunable mesoporous carbon material[6] that gives a high active site density and good conductivity.NCS material, having a pore size of either 12, 50 or 85 nm, was heated in NH3 gas at 700 °C for 7 hours to prepare N-doped NCS. SEM and TEM were used to confirm the NCS morphology, while XPS, EDX and elemental analysis were used to determine the N content of the NCS material. The electrochemical performance of the N-doped NCS was carried out first using CV in CO2 sat. 0.1 M KHCO3 in a glass cell. After that, a membrane electrode assembly (MEA) CO2 electrolyzer was used to determine the CO2 reduction activity. An N-doped NCS (IrO2-coated) was used as the anode and an anion exchange membrane (AEM) was used as the separator during CO2 electrolysis, with humidified CO2 gas used at the cathode side. The gas products were collected from the cathode outlet and injected into a gas chromatography system for analysis. No liquid products were observed in the solution that was released to the cell outlet.The performance of N-doped NCS will be presented based on the results obtained in various solution-flow cell configurations. Effect of N-doped NCS preparation optimization will also be discussed. Based on both the CV results and the MEA CO2 electrolyzer data, the onset potential of CO2RR was comparable to what has been reported by others for N-doped carbons, but the high internal surface area of the NCS, combined with its high extent of N doping, may give the N-doped NCS some advantages. A maximum 90% FECO was achieved and the stability of the catalytic material was also studied in the flow cell systems.

Highly Selective and Scalable Electrolysis for Gaseous CO2 Reduction in the Zero-Gap Electrolyzer

The electroreduction of carbon dioxide (CO2) to chemicals represents a promising pathway for the storage of renewable electricity and toward low-carbon-footprint chemicals production. Prior study on CO2RR have focused on the catalytic properties of various materials in liquid condition. However, the current density for CO2RR is restricted under 30 mA cm–2 due to the mass transfer limit and low solubility of CO2 in the aqueous solution. To increase the current density, the gas fed CO2 electrolysis system was investigated using a gas-diffusion layer (GDL) system. Masel et al. reported about new zero-gap CO2 electrolysis device that uses an anion exchange membrane (AEM, SustainionTM) with humidified CO2 flow in the cathode and shows a current density of 200 mA cm-2 with steady FECO of over 90% using Ag catalyst.Herein, we developed a convenient Ag-based and Cu-based electrode with high selectivity and high current density for electrochemical conversion of CO2 to CO and ethylene in a zero-gap electrolyzer, respectively. We tested the electrochemical properties of the prepared Ag-based electrode in the gaseous CO2-fed electrolyzer and H-type electrochemical cell with respect to CO2RR. Ag coral electrode achieves CO partial current density of 312 mA cm–2 with FECO > 95%. Cu-KOH electrode demonstrate 260 mA cm–2 current density with 60.5 % C2H4 faraday efficiency at 10 cm2 electrode area. Moreover, the prepared electrode was analyzed the change of electronic structure using in-situ/operando X-ray absorption spectroscopy (XAFS) at real gas fed zero-gap electrolyzer condition. Based on these results, we could give insights about the scalable electrolyzer system for electrochemical conversion of CO2 with high catalytic activity and selectivity.

Metal-Nitrogen-Carbon Electrocatalysts for CO2 Reduction towards Syngas Generation.

Shifting syngas (an H2 /CO mixture) production away from fossil-fuel-dependent processes (e.g., steam methane reforming and coal gasification) is mandatory, as syngas is of interest as both a fuel and as a value-added chemical precursor. With appropriate electrocatalysts, such as silver-based and metal-nitrogen-carbon (M-N-C) materials, the electrochemical CO2 reduction reaction (CO2 RR) allows for the production of CO alongside H2 (from the hydrogen evolution reaction), and thus leads to syngas generation. In this Minireview, the application of M-N-C electrocatalysts for syngas generation is discussed. The mechanisms leading to different faradaic selectivities for CO are reviewed as a function of the nature of the metal, by using both computational and experimental approaches. The role played by the metal-free moieties in the M-N-C electrocatalysts is underlined. Since M-N-C electrocatalysts only recently entered the CO2 RR field (as opposed to Cu-, Ag-, or Au-based nanostructures), they have been mainly characterized in static liquid environments, in which the reaction rate is significantly hampered by CO2 -dissolution/diffusion limitations. Therefore, the design of CO2 RR electrolyzers for M-N-C electrocatalysts is addressed, and designs such as zero-gap electrolyzers with anionic membranes and humidified CO2 gas feed at the cathode are highlighted.

Standardization of in vitro nervous tissue culture for honeybee: A high specificity toxicological approach.

Bees are important pollinators that help to maintain the biodiversity of wild and cultivated plants. However, the increased and inappropriate use of agrochemicals has caused an imbalance in the populations of these insects visiting flowers for pollen and nectar collection. Therefore, new research methods for understanding the mechanisms of action of pesticides and their impacts on the brains of bees, such as neurotoxicity and cellular changes, in response to different active characteristics and dosages of insecticides are necessary. Thus, with the aim of developing tests with greater specificity at the level of cells or tissues, this study sought to standardize a method for the in vitro culture of the nervous tissue of Apis mellifera. For this purpose, the brains of six foragers bees were transferred to three different insect cell culture media and it supplementation with 10% foetal bovine serum (FBS): Grace, Schneider, Leibovitz, Grace+FBS, Schneider+FBS and Leibovitz+FBS media for each collection time. Nervous tissue was collected after 1, 6, 12 and 24h of incubation in a humidified CO2 incubator at 32°C, and histological sections of the organs were analysed. The results showed that Leibovitz medium and Leibovitz medium+serum are potential culture media for the cultivation of nervous tissue, since they resulted in less tissue spacing and tissue disarrangement. Therefore, additional supplements are necessary to obtain an ideal medium for the cultivation of A.mellifera nervous tissue.

Two-step electrochemical reduction of CO2 towards multi-carbon products at high current densities

Two-step electrochemical reduction of CO2 is investigated as an alternative to increase selectivity towards C2 and C3 products. In this type of proposed cascade electrocatalytic operation, CO is produced in a first step and subsequently reduced to multi-carbon products in a second step with significantly higher Faradaic efficiencies compared to a one-step process. Research efforts have been focused on the feasibility of the isolated second step with pure CO as reactant, however the interdependencies of both steps need to be considered. Accordingly, two-step electrochemical reduction of CO2 is studied in this work as an integrated system. Taking into account that the study of this technology at high current densities is crucial for industrial applicability, gas diffusion electrodes and flow-cells were used for operation at current densities above −200 mA cm−2 . Firstly, each step was characterized separately, the first using a silver gas diffusion electrode to generate a mixture of humidified CO, H2, and unreacted CO2; the second step using copper nanoparticles on a carbon-based gas diffusion structure to obtain C2 and C3 products. This step was studied using synthetic mixtures of CO2 and CO with different ratios. Furthermore, experiments with isotope labeled 13CO2 and 13CO were performed in order to obtain some insights on the (electrochemical) reaction path of gas mixtures containing CO2 and CO. Subsequently, the two units were integrated into a system, where the full gas output of the first unit was directly fed to the second unit. The total Faradaic efficiency towards multi-carbon products of this initial system was limited to 20% at total current density of −470 mA cm−2. These initial results together with the isotopic labeling studies indicate that the presence of significant amounts of unreacted CO2 from the first step is detrimental for the second step. A significant improvement was achieved by introducing a CO2 absorption column between the two units and after splitting the overall charge flow applied in each cell in accordance with the main reaction at each step. With this set-up a total Faradaic efficiency towards C2 and C3 products of 62% at a total current density of −300 mA cm−2 was achieved. The results confirm the need for a gas separation technique between the two steps for a feasible two-step electrochemical reduction of CO2.

Influence of Local Insufflation of Warm Humidified CO2 on the Wound Surface and Body Core Temperature as well as on Wound Healing in Open Colorectal Surgery

Perioperative hypothermia may lead to serious complications. This study aims to investigate whether intraoperative insufflation of warmed and humidified carbon dioxide (W-H-CO2) into the open wound during open colorectal surgery influences body core and wound surface temperatures or the incidence of wound healing disorders (WHD). Between 02/2018 and 07/2019, 50 patients intended to undergo open resection for colorectal cancer were recruited and randomised to a control group (n = 25) and an experimental group (n = 25). In the experimental group, a device for insufflation of W-H-CO2 was used. Body core and wound surface temperatures were recorded at the beginning and before finishing the procedure. IL-6 serum levels were determined preoperatively and during the postoperative course. Clinical observation of wound healing was performed until the 30th day post-op. Both groups were homogeneous in terms of risk factors for WHD. In the control group, the median body core temperature (1. quartile/3. quartile) was 36.2 °C (36/36.4 °C) when the operation started and 36.2 °C (35.9/36.45 °C) at the end, while in the experimental group it was initially 36.2 °C (35.7/36.4 °C) and 36.4 °C (36/36.7 °C) at the end. There was no significant difference between the two groups (p = 0.08). The wound temperature in the control group dropped from 32.8 °C (median; 31.85/34.05 °C) to 30.7 °C (median; 29.85/32.15 °C). In the experimental group, we recorded a drop from 31.9 °C (median; 30.25/32.95 °C) to 31.6 °C (median; 30.25/31.85 °C), which was statistically significant (p = 0.000475). The dynamic of the IL-6 serum levels in both groups suggest that there was no significant difference (p = 0.66; p = 0.88; p = 0.88). In the control group, 8 patients experienced superficial WHD, 2 anastomotic leakages (AL), while in the experimental group, superficial WHD were observed in 5 patients and AL in 1 patient. This differences between the groups regarding in WHD were not significant (p = 0.42). The established measures for prevention of perioperative hypothermia in elective procedures are sufficient. However, the local wound surface temperature is not preserved satisfactorily. Deployment of a device for intraoperative insufflation of W-H-CO2 into open wounds may be suitable for maintaining local normothermia. Further studies are needed to determine the influence of warm and humid CO2 on wound healing.

Impact of heat challenge on expression dynamics of HSP90 in cardiac cells of goat

ABSTRACT The present study was aimed with an objective to investigate the effect of heat challenge on the expression dynamics of heat shock protein 90 (HSP90) mRNA in cultured cardiac cells of goat. The heart tissues (n = 6) from different goats were used for the culture study. The cardiac cells obtained from different heart tissues were cultured in 24-well cell culture plates and incubated in a humidified CO2 (5%) incubator at 39°C. The cardiac cells were allowed to become 75–80% confluent after 72 h of incubation. Then, the cardiac cells were subjected to heat challenge at 42°C for 0, 20, 60 and 100 min. The cardiac cells exposed to heat challenge at 42°C for 0 min was taken as control. The relative abundance of HSP90 mRNA was assessed by quantitative real-time PCR (qRT-PCR). The relative abundance of HSP90 mRNA did not change at 20 min of heat challenge as compared to control. Thereafter, the relative abundance of HSP90 mRNA was significantly increased (P < 0.05) at 60 and 100 min of heat challenge. However, the relative abundance of HSP90 mRNA was registered to be highest (P < 0.05) at 100 min of heat challenge. The present study suggests that overexpression of HSP90 mRNA could safeguard cardiac cell against the detrimental effect of heat stress and may provide thermo-tolerance to goat during extreme environmental conditions.

Prevention of Intraoperative Hypothermia in Laparoscopy by the Use of Body-Temperature and Humidified CO2: a Pilot Study

Introduction Hypothermia is defined as a decrease in body core temperature to below 36 °C. If intraoperative heat-preserving measures are omitted, a patientʼs temperature will fall by 1 – 2 °C. Even mild forms of intraoperative hypothermia can lead to a marked increase in morbidity and mortality. The temperature of the insufflation gas is usually disregarded in the treatment and prevention of hypothermia. This study was conducted to investigate the effect of body-temperature and humidified CO 2 on the intraoperative temperature profile and avoidance of hypothermia in laparoscopic surgery. Material and Methods In this retrospective, non-randomised case control study, 110 patients whose planned operation lasted at least 60 minutes were identified from 376 patients by means of an algorithm. Dry (20% humidity) CO 2 at room temperature was insufflated in 51 patients (control group). 59 patients were insufflated with humidified (98% humidity) CO 2 at body temperature (37 °C) (study group). These conditions were achieved with the HumiGard MR860 Surgical Humidification System (Fisher & Paykel Healthcare Limited, Auckland, New Zealand). The intraoperative temperature profile was evaluated by measurements every 10 minutes. Statistical analysis was performed with IBM ® SPSS ® Statistics 23.0.0. Results The intraoperative temperature in the control group fell steadily, while a continuous rise in temperature was observed in the study group. Warming was demonstrated in the study group with a start-end temperature difference of 0.09 °C, which differed significantly from the control group, in which it was − 0.09 °C (p = 0.011). The middle-end difference of 0.11 °C showed even higher significance in favour of the warmed gas (p = 0.003). The rate of hypothermia at the start of the operation fell from 50 to 36% in the study group and increased from 36 to 42% in the control group. Conclusion These results show that the use of body-temperature and humidified insufflation gas for laparoscopy can help to prevent intraoperative hypothermia.

In-Operando Changes of the Cation Exchange Membrane in CO2 electrolyzers

CO2 electrolysis provides a promising solution for reducing CO2 concentration levels in the atmosphere and for decarbonizing current CO2 sources. Through CO2 electrolysis, we can synthesize syngas, formic acid, and other useful hydrocarbon feedstocks [1] for carbon-neutral fuels, creating a cyclic consumption of hydrocarbons. A critical limitation of industrializing current CO2 electrolyzer designs is understanding the mass and ionic transport effects of the reactants and products across the membrane-electrode assembly [1,2]. These effects are directly dependent on the operating conditions and reduce cell performance [1]. Membrane hydration is an important parameter that significantly affects cell performance and optimum performance can be achieved by supplying humidified CO2 gas supply at the cathode, as evident in fuel cell technologies [3]. In this study, we investigated the impact of humidified CO2 gas supply on cell performance and correlated it with mass transport effects causing changes in the cation exchange membrane (CEM). We operated a CEM CO2 electrolyzer with varied cathode gas inlet relative humidity (RH) to study the performance change at various current densities while simultaneously using synchrotron X-ray radiography to quantify membrane hydration changes and water dynamics. These results were coupled with electrochemical impedance spectroscopy (EIS) data, which gave us the high frequency resistance (HFR) highlighting the ohmic losses present in the membrane at various RH conditions. Similar work on other electrochemical devices (fuel cells [4] and water electrolyzers [5]) has shown the relationship between cell performance and changes in membrane hydration and transport resistance. Significant improvement in cell performance was observed as the cathode inlet RH increased. This improvement is a direct result of increased membrane hydration. Furthermore, EIS data exhibited a significant decrease in HFR as RH increased, indicative of lower ionic transport resistance across the membrane. As the electrolyzer is operated at various current densities, the through plane visualizations of the CEM provide insight into the relative changes in the membrane. Mass transport phenomena have a significant effect on cell performance at elevated current densities, which is evident by in-operando membrane hydration changes and membrane ohmic losses. From our observations, the humidification of CO2 gas supply has a significant effect on cell performance. We believe this knowledge can be translated into substantially improving the performance of CO2 electrolyzers for industrial-scale implementation.

Clinical effects of warmed humidified carbon dioxide insufflation in infants undergoing major laparoscopic surgery

Purpose:Some studies have reported that warmed humidified carbon dioxide (CO2) insufflation in adult laparoscopic surgery could reduce pain and improve the core body temperature (CBT). However, similar studies are lacking in infants. Thus, this study aimed to investigate the clinical effects of warmed, humidified CO2 insufflation in pediatric patients undergoing major laparoscopic surgeries.Methods:From January 2015 to December 2017, infants who underwent major laparoscopic surgeries in Ningbo Women and Children's Hospital were randomized to Group A (standard CO2 insufflation) or Group B (warmed humidified CO2 insufflation, 35°C, 95% relative humidity). Change in CBT at the end of surgery was the primary outcome. Secondary outcomes included surgery time, intraoperative blood loss, oxygen saturation (SO2), and Face, Legs, Activity, Cry and Consolability (FLACC) scale. These variables were compared between the 2 groups.Results:Sixty-three infants (38 females, 25 males) were included; 30 patients were in Group A and 33 in Group B. The diseases treated with the laparoscopic approach included congenital megacolon, congenital diaphragmatic hernia, and intestinal malrotation. No deaths were noted. CBT was significantly higher in Group B at the end of surgery (P = .021). The occurrence of postoperative shivering (P = .02), hypothermia (P = .032), bowel movement (P = .044), and hospital stay (P = .038) was significantly different between the 2 groups; Group B had less shivering and hypothermia occurrence after surgery. Moreover, Group B demonstrated a more rapid postoperative recovery of bowel movement and shortened hospital stay than Group A. There was no statistical difference in operative time (P = .162), intraoperative blood loss (P = .541), SO2 (P = .59), and FLACC scale (P = .65) between the 2 groups.Conclusion:The use of warmed humidified CO2 insufflation in infants undergoing major laparoscopic surgery was helpful for maintaining normothermia and was associated with several positive postoperative outcomes, including less shivering and hypothermia, faster recovery of bowel movement, and shortened hospital stay.

Investigation on fuel gas production from pulp and paper waste water impregnated coconut husk in fluidized bed gasifier via humidified air and CO2 gasification

The waste biomass has immense opportunities and plenty of potentials to be an efficient source of renewable energy. Initially, native unripe coconut husk (NCH) was used as raw material for fluidized bed gasification. Then NCH was treated with paper and pulp waste water to impregnate metals present in it for getting enhanced H2 yield in fuel gas. Humidified air was used as gasifying medium, which served the purpose of introducing water vapour to take part in the gasification process. Then after, gasification medium was retrofitted with CO2, which enhanced both the higher heating value (HHV), and CO and H2 content in the fuel gas. This research serves the dual benefit of energy generation and waste minimization. HHV of unripe coconut husk was investigated and found to be 20.95 MJ/kg. H2 yield and HHV from impregnated coconut husk (ICH) were obtained as 55.55 vol % and 5.24 MJ/Nm3, respectively at HER 0.1 and gasification temperature of 850 °C in case of fluidized bed gasification. The GC-MS analysis of fuel oil obtained from ICH gasification was done to get the information about high yield of fuel gas as promise product of fluidized bed gasification.

The impact of warmed and humidified CO2 insufflation during robotic radical prostatectomy: Results of a randomized controlled trial.

Cool and dry gas insufflation during laparoscopy induces hypothermia and cytokine increase, with significant perioperative morbidity. Our aim was to assess if warmed and humidified CO2 insufflation with HumiGard™ device can achieve significant benefits over standard insufflation in terms of risk of hypothermia, cytokine response, blood gases, and intra- and postoperative parameters, in the setting of robot-assisted radical prostatectomy (RARP). This was a prospective, randomized controlled clinical trial. Sixty-four patients with prostate cancer undergoing RARP were randomized to receive warmed and humidified CO2 insufflation with HumiGard device, plus hot air warming blanket (treatment group, H + WB), or standard CO2 insufflation, plus hot air warming blanket (control group, WB). Body core temperature (BCT), plasma levels of IL-6 and TNF-α, pain scores, and intraoperative parameters were recorded. The data were analyzed according to the Bayesian paradigm. Intraoperative BCT increased in both groups during surgery, with a statistically significant difference favoring group H + WB, ending at 0.2°C higher on average than group WB. No difference across groups was shown for cytokine levels. Blood gas parameters were not affected by warmed CO2 insufflation. No statistical differences were noted for pain scores and the other intra- and postoperative parameters. During RARP, warm and humidified CO2 insufflation with the HumiGard device was more effective than the standard CO2 insufflation in maintaining the patient's heat homeostasis, even if the difference was minimal. No imbalances were detected on blood gas analyses. No benefit could be shown in terms of cytokine levels and pain scores.