High CO2 Concentration Research Articles

Electrolyte Design Using "Porous Water” for High‐purity Carbon Monoxide Electrosynthesis from Dilute Carbon Dioxide

Electrosynthesis of high‐purity carbon monoxide (CO) from captured carbon dioxide (CO₂) remains energy‐intensive due to the unavoidable CO₂ regeneration and post‐purification stages. Here, we propose a direct high‐purity CO electrosynthesis strategy employing an innovative electrolyte, termed porous electrolyte (PE), based on "porous water". Zeolite nanocrystals within PE provide permanent pores in the liquid phase, enabling physical CO₂ adsorption through an intraparticle diffusion model, as demonstrated by molecular dynamics simulations and in‐situ spectral analysis. Captured CO₂ spontaneously desorbs under applied reductive potential, driven by the interfacial CO₂ concentration gradient, and is subsequently reduced electrochemically. The high CO₂ concentration in PE enhances mass transfer, and surface ion exchange between Si–OH groups and K⁺ ions on the zeolite surface generates a stronger interfacial electric field, promoting electron transfer steps. This optimized kinetics for mass and electron transfer confers heightened intrinsic activity toward CO₂ electroreduction. The PE‐based electrolysis system demonstrated superior CO Faradaic efficiency and partial current density compared to the conventional CO₂‐fed system. A circular system using PE and a Ni‐N/C cathode realized continuous production of high‐purity CO (97.0 wt%) from dilute CO2 (15%) and maintained > 90.0 wt% under 150 mA cm‐2, with significantly reduced energy consumption and costs.

Electrolyte Design Using "Porous Water" for High-purity Carbon Monoxide Electrosynthesis from Dilute Carbon Dioxide.

Electrosynthesis of high-purity carbon monoxide (CO) from captured carbon dioxide (CO₂) remains energy-intensive due to the unavoidable CO₂ regeneration and post-purification stages. Here, we propose a direct high-purity CO electrosynthesis strategy employing an innovative electrolyte, termed porous electrolyte (PE), based on "porous water". Zeolite nanocrystals within PE provide permanent pores in the liquid phase, enabling physical CO₂ adsorption through an intraparticle diffusion model, as demonstrated by molecular dynamics simulations and in-situ spectral analysis. Captured CO₂ spontaneously desorbs under applied reductive potential, driven by the interfacial CO₂ concentration gradient, and is subsequently reduced electrochemically. The high CO₂ concentration in PE enhances mass transfer, and surface ion exchange between Si-OH groups and K⁺ ions on the zeolite surface generates a stronger interfacial electric field, promoting electron transfer steps. This optimized kinetics for mass and electron transfer confers heightened intrinsic activity toward CO₂ electroreduction. The PE-based electrolysis system demonstrated superior CO Faradaic efficiency and partial current density compared to the conventional CO₂-fed system. A circular system using PE and a Ni-N/C cathode realized continuous production of high-purity CO (97.0 wt%) from dilute CO2 (15%) and maintained > 90.0 wt% under 150 mA cm-2, with significantly reduced energy consumption and costs.

Screening of Bacteria Promoting Carbon Fixation in Chlorella vulgaris Under High Concentration CO2 Stress

The cooperation between microalgae and bacteria can enhance the carbon fixation efficiency of microalgae. In this study, a microalgae-bacteria coexistence system under high-concentration CO2 stress was constructed, and the bacterial community structure of the entire system was analyzed using the 16S rDNA technique. Microbacterium sp., Bacillus sp., and Aeromonas sp. were screened and demonstrated to promote carbon fixation in Chlorella vulgaris HL 01 (C. vulgaris HL 01). Among them, the Aeromonas sp. + C. vulgaris HL 01 experimental group exhibited the most significant effect, with an increase of about 24% in the final biomass yield and a daily carbon fixation efficiency increase of about 245% (day 7) compared to the control group. Continuous cultivation of microalgae and bacterial symbiosis showed that bacteria could utilize the compounds secreted by microalgae for growth and could produce nutrients to maintain the vitality of microalgae. Detection of extracellular organic compounds of microorganisms in the culture broth by excitation-emission matrix spectral analysis revealed that bacteria utilized the aromatic proteinaceous compounds and others secreted by C. vulgaris HL 01 and produced new extracellular organic compounds required by C. vulgaris HL 01. The metabolic organic substances in the liquids of the experimental groups and the control group were analyzed by liquid chromatography-mass spectrometry, and it was found that 31 unique organic substances of C. vulgaris HL 01 were utilized by bacteria, and 136 new organic substances were produced. These differential compounds were mainly organic acids and their derivatives, benzene compounds, and organic heterocyclic compounds, etc. These results fully demonstrate that the carbon fixation ability and persistence of C. vulgaris HL 01 are improved through material exchange between microalgae and bacteria. This study establishes a method to screen carbon-fixing symbiotic bacteria and verifies that microalgae and bacteria can significantly improve the carbon fixation efficiency of microalgae for high-concentration CO2 through material exchange, providing a foundation for further research of microalgae-bacterial carbon fixation.

Bicarbonate use reduces the photorespiration in Ottelia alismoides adapting to the CO2-fluctuated aquatic systems.

Underwater CO2 concentration fluctuates extremely in natural water bodies. Under low CO2, the unique CO2 concentrating mechanism in aquatic plants, bicarbonate use, can suppress photorespiration. However, it remains unknown (1) to what extent bicarbonate use reduces photorespiration, (2) how exactly photorespiration varies between bicarbonate-users and CO2-obligate users under CO2-fluctuated environments, and (3) what are differences in Rubisco characteristics between these two types of aquatic plants. In the present study, the bicarbonate user Ottelia alismoides and its phylogenetically close CO2-obligate user Blyxa japonica were chosen to answer these questions. The results showed that bicarbonate use saved ~13% carbon loss under low CO2 via decreasing photorespiration in O. alismoides. Through bicarbonate use, the photorespiration of O. alismoides was kept stable both under high and low underwater CO2 concentrations, while the photorespiration significantly increased in the CO2-obligate user B. japonica under low CO2. However, B. japonica showed a significantly higher photosynthesis rate than O. alsimoides when CO2 was sufficient. These differences could be related to the kinetic characteristics of Rubisco showing a higher carboxylation turnover rate (Kcat) in B. japonica, and the similar affinity to CO2 (Kc) and specificity factor (Sc/o) in these two species that might be determined by the variation of six amino acid residuals in Rubisco large subunit sequences, especially the site 281 (A vs. S) and 282 (H vs. F). All these differences in photorespiration and kinetic characteristics of Rubisco could explain the distribution patterns of bicarbonate users and CO2-obligate users in the field.

Photosynthesis in Synechocystis sp. PCC 6803 is not optimally regulated under very high CO2

One strategy for CO2 mitigation is using photosynthetic microorganisms to sequester CO2 under high concentrations, such as in flue gases. While elevated CO2 levels generally promote growth, excessively high levels inhibit growth through uncertain mechanisms. This study investigated the physiology of the cyanobacterium Synechocystis sp. PCC 6803 under very high CO2 concentrations and yet stable pH around 7.5. The growth rate of the wild type (WT) at 200 µmol photons m−2 s−1 and a gas phase containing 30% CO2 was 2.7-fold lower compared to 4% CO2. Using a CRISPR interference mutant library, we identified genes that, when repressed, either enhanced or impaired growth under 30% or 4% CO2. Repression of genes involved in light harvesting (cpc and apc), photochemical electron transfer (cytM, psbJ, and petE), and several genes with little or unknown functions promoted growth under 30% CO2, while repression of key regulators of photosynthesis (pmgA) and CO2 capture and fixation (ccmR, cp12, and yfr1) increased growth inhibition under 30% CO2. Experiments confirmed that WT cells were more susceptible to light inhibition under 30% than under 4% CO2 and that a light-harvesting-impaired ΔcpcG mutant showed improved growth under 30% CO2 compared to the WT. These findings suggest that enhanced fitness under very high CO2 involves modifications in light harvesting, electron transfer, and carbon metabolism, and that the native regulatory machinery is insufficient, and in some cases obstructive, for optimal growth under 30% CO2. This genetic profiling provides potential targets for engineering cyanobacteria with improved photosynthetic efficiency and stress resilience for biotechnological applications.Key points• Synechocystis growth was inhibited under very high CO2.• Inhibition of growth under very high CO2 was light dependent.• Repression of photosynthesis genes improved growth under very high CO2.Graphical

An Investigation of the Catalytic Activity of Inconel and Stainless Steel Powders in Reforming Primary Syngas

Biomass is perhaps the only renewable resource on the planet capable of delivering molecules similar to those derived from petroleum, and one of the most developed technologies to achieve this is gasification. When it comes to biomass conversion into fuels and commodities, supercritical water gasification (SCWG) could offer promising solution for producing hydrogen-rich syngas. However, the presence of methane (CH4) and carbon dioxide (CO2) in the syngas could negatively impact downstream processes, particularly when carbon monoxide is also required. Hence, improving the quality of the syngas produced from biomass gasification is essential for promoting the sustainability of several industrial processes. In this context, understanding the principles of the dry reforming of methane (DRM) becomes essential for upgrading syngas with high CH4 and CO2 content, especially when the carbon monoxide content is low. In addition to the experimental conditions used in such process, it has been reported that the material composition of the reactor can impact on reforming performance. Hence, this work aims at comparing the catalytic efficacy of Inconel and stainless steel for reforming syngas derived from SCWG under standard DRM conditions. In this specific work, the metals were directly used as catalyst and results showed that when using Inconel powder, CH4 conversion increased from 3.03% to 37.67% while CO2 conversion went from 23.16% to 51.48% when compared to stainless steel. Elemental and structural analyses revealed that the Inconel’s superior performance might be due to its high nickel content and the formation of active oxide compounds, such as FeNiO, FeCrO3, Fe3O4, Cr2O3, and Cr2NiO4, during the reaction. In contrast, Fe3O4 was the only oxide found in stainless steel post-reaction. Additionally, increasing the total gas feed flow rate was shown to reduce CH4 and CO2 conversions, supporting the known impact of residency time on catalytic efficiency.

Estimating CO2 response in a mixed broadleaf forest using the dynamic assimilation technique

BackgroundEstimating the CO2 response of forest trees is of great significance in plant photosynthesis research. CO2 response measurement is traditionally employed under steady state conditions. With the development of open-path gas exchange systems, the Dynamic Assimilation Technique (DAT), allows measurement under non-steady state conditions. This greatly improves the efficiency and data density of CO2 response measurement. This study aims to assess the accuracy and effectiveness of different models in fitting DAT data, addressing the current gap in verification of model performance.ResultsThis research was conducted for three common broadleaf tree species (Ulmus macrocarpa, Fraxinus mandshurica, and Tilia amurensis) in North Eastern China. Among the three species, Fraxinus mandshurica is the most adapted to high CO2 concentration conditions. Four models were compared, the rectangular hyperbola (RH) model, the Michaelis-Menten (MM) model, the modified rectangular hyperbola (MRH) model and a non-rectangular hyperbola (NRH) model.ConclusionsConsidering the model parsimony and parameter accuracy, the NRH model emerged as the best choice (R2 = 0.9966, RMSE = 0.1862, AIC=-199.86). This study provides a reference for the further application of DAT in the field of photosynthesis.

Tracking hydrothermal infiltration within light oil reservoirs using organic geochemical proxies in the Shunbei area of Tarim Basin in China

Deep oil reservoirs are becoming increasingly significant fields of hydrocarbon exploration in recent decades. Hydrothermal fluid flow is deemed as a potentially crucial factor affecting the occurrence of deep oil reservoirs, such as enhancing porosity/permeability of reservoirs, accelerating oil generation and thermal cracking, and modifying organic properties of crude oils. Understanding the interplay between hydrothermal fluids and crude oils would provide useful constraints for reconstructing hydrocarbon accumulation processes and predicting the distribution patterns of crude oils. Voluminous crude oils have been discovered in the deeply buried Ordovician carbonate reservoirs within the Shunbei area of the northern Tarim Basin. Previous studies revealed that the Early Permian Tarim Large Igneous Province (LIP) has affected the Shunbei area, whereas it is still debated whether the LIP-related hydrothermal infiltration affected hydrocarbons within the Ordovician reservoirs. To resolve this puzzle, this study was designed to unravel the potential thermal impact of hydrothermal infiltration on hydrocarbons according to molecular and stable carbon isotopic compositions of oils and associated natural gases, reflectance analysis of solid bitumen, and fluid inclusion thermometry. The studied crude oils are characterized by uniform organic indicators of paraffin, terpanes, steranes, and light hydrocarbons, implying that crude oils are derived from the same source rock. Genetic binary diagrams, such as dibenzothiophene/phenanthrene (DBT/P) vs. Pr/Ph (pristane/phytane), Pr/n-C17 alkane vs. Ph/n-C18 alkane, C31R/C30hopane vs. C26/C25tricyclic terpane (TT), and C24/C23 TT vs. C22/C21 TT, indicate that marine shales deposited in a reducing-weakly oxidized environment are major source rocks. Natural gases are associated with oil reservoirs and are mainly generated via the decomposition of kerogen and crude oil. Solid bitumen with abnormally high reflectance values (2.17–2.20%) occurred in the studied area, suggesting their formation temperatures were 252–254 °C. The abnormally high temperatures may be caused by hydrothermal infiltration related to the Tarim LIP. Hydrothermal infiltration is supported by the presence of high contents of CO2 (30–48%) with enriched δ13C ratios (between − 2.5‰ and − 2.3‰), enriched n-alkane δ13C ratios, and incongruent temperatures estimated by multiple indicators, such as light hydrocarbon compositions, homogenization temperatures of fluid inclusions, and bitumen reflectance. Outcomes of this study support the interpretation that hydrothermal infiltration indeed occurred and may have facilitated hydrocarbon generation in the Shunbei area, and possibly elsewhere in the cratonic regions of the northern Tarim Basin.

Assessment of Indoor Classroom Environment Quality Associated with Student Sleepiness: Pathways Towards a Sustainable Environment Through a Pilot Study

Student sleepiness during classes is a frequently reported condition that can impair performance in the teaching–learning process and is even unsustainable for health. Although the environmental quality of the classroom may affect the students’ sleepiness, studies that exhaustively investigate the relationship between indoor environmental quality (IEQ) and sleepiness levels in classrooms are lacking. To this end, in the present paper, we carried out an experimental pilot study involving twenty-seven Italian adolescent students to determine the increase in their sleepiness rate during the school period utilizing the Epworth Sleepiness Scale (ESS). The analysis was performed in a classroom in which the indoor environmental quality was monitored, including measurements of the thermal comfort, sound pressure level, illuminance, carbon dioxide (CO2) concentrations, and airborne particle concentrations (both sub-micrometric particles and PM10). Three measurement days were considered. The results showed that student sleepiness significantly increased during the school period (Day 1 p = 0.00, Day 2 p = 0.03, and Day 3 p = 0.03). This increase was observed on measurement days characterized as having both perceived higher and lower thermal comfort and even in the presence of limited exposure to airborne particle concentrations, presenting an association with the high indoor concentration of CO2 detected in the classroom (Day 1 between 978 and 3261 ppm; Day 2 between 1044 and 2338 ppm; Day 3 between 1116 and 2623 ppm), due to reduced ventilation rates and the students’ sleepiness. Thus, the findings suggest that adequate ventilation rates can limit the increase in the rate of sleepiness, indicating, from our pilot study, that recommendations of sustainable environmental practices through comprehensive feasibility studies can promote positive changes in indoor environments such as classrooms.

A review of biogas upgrading technologies: key emphasis on electrochemical systems.

Biogas, consisting mainly of CO2 and CH4, offers a sustainable source of energy. However, this gaseous stream has been undervalued in wastewater treatment plants owing to its high CO2 content. Biogas upgrading by capturing CO2 broadens its utilisation as a substitute for natural gas. Although biogas upgrading is a widely studied topic, only up to 35% of produced raw biogas is upgraded in the world. To open avenues for development research on biogas upgrading, this paper reviews biogas as a component in global renewable energy production and upgrading technologies focusing on electrochemically driven CO2 capture systems. Recent progress in electrochemical CO2 separation including its energy requirement, CO2 recovery rate, and challenges for upscaling are critically explored. Electrochemical CO2 separation systems stand out for achieving the most affordable technology among the upgrading systems with a low net energy requirement of 0.25 kWh/kg CO2. However, its lower CO2 recovery rate compared to conventional technologies, which leads to high capital expenditure limits the commercialisation of this technology. In the last part of this review, the future perspectives to overcome the challenges associated with electrochemical CO2 capture are discussed.

REMOVAL OF DEPOSITS AND IMPROVEMENT OF SHELF LIFE IN CO2-RICH MINERAL WATER BY OZONE MICROBUBBLES

The aim of this study was to effectively remove Fe2+ by using ozone microbubbles in bottled mineral water to prevent sediment from occurring during storage and increase shelf life. By considering the characteristics of mineral water with low solubility of ozone and high CO2 content, a suitable ozone injection step was chosen and a new mineral water treatment method using microbubbles was proposed. As a result of the treatment of the bottled mineral water with ozone microbubbles, the concentration of the iron ion was reduced from 0.14 to 0.01 mg L-1, and the shelf life increased to 360 days. During the treatment, the concentrations of K+ and Na+ were almost unchanged, and the deposition time was reduced to one-third compared to the natural oxidation.

Identification and expression analysis of lncRNAs in rice roots (Oryza sativa L.) under elevated CO2 concentration and/or cadmium stress.

The gradual rise of CO2 is one of the global climate changes, Cd stress is also a major abiotic stress factor that affects rice (Oryza sativa L.). The rice seedlings were treated under two CO2 concentrations and two CdCl2 concentrations for 7 days (treatments names: 400 ± 20 μmol mol-1 CO2 and 0 μmol L-1 CdCl2 concentrations, AC; 400 ± 20 μmol mol-1 CO2 and 150 μmol L-1 CdCl2 concentrations, Cd; 800 ± 20 μmol mol-1 CO2 and 0 μmol L-1 CdCl2 concentrations, EC; 800 ± 20 μmol mol-1 CO2 and 150 μmol L-1 CdCl2 concentrations, EC + Cd). The lncRNAs informations were analyzed and excavated using high-throughput sequencing, target genes annotation, and qRT-PCR analysis techniques so as to reveal the regulatory mechanism of lncRNAs in rice roots under high CO2 concentrations and/or Cd stress. The results show that: (1) 326 (AC vs Cd), 331 (AC vs EC), 343 (AC vs EC + Cd), 112 (Cd vs EC + Cd) DE-lncRNAs were identified. (2) MAPK signaling pathway-plant (relevant genes Os04g0534166, Os05g0399800 regulated by MSTRG.18576.11, MSTRG.20864.1) and diterpenoid biosynthesis (relevant genes Os12g0491800, Os02g0570400 regulated by MSTRG.8965.1, MSTRG.11509.1) were annotated in AC vs Cd; Under EC relative to AC, DE-lncRNAs were annotated significantly to the flavonoid biosynthesis (relevant genes Os10g0196100, Os10g0320100, Os11g0116300, Os03g0819600 regulated by MSTRG.4612.1, MSTRG.4668.1, MSTRG.6051.1, MSTRG.16669.1); Under composite treatments, relative to AC, DE-lncRNAs were mainly annotated in the plant hormone signal transduction pathway (relevant genes Os03g0180800, Os03g0180900, Os03g0181100 regulated by MSTRG.13776.1). Under combined treatment, elevated CO2 alleviates Cd stress damage by regulating phenylpropanoid biosynthesis through DE-lncRNAs (relevant genes Os09g0419200 regulated by MSTRG. 29,573.1).

Performance of flare gas ultrasonic flow measurement at high CO2 concentration flows

Performance of flare gas ultrasonic flow measurement at high CO2 concentration flows

Monitoring of indoor air quality at a large sailing cruise ship to assess ventilation performance and disease transmission risk.

Large passenger ships are characterised as enclosed and crowded indoor spaces with frequent interactions between travellers, providing conditions that facilitate disease transmission. This study aims to provide an indoor ship CO2 dataset for inferring thermal comfort, ventilation and infectious disease transmission risk evaluation. Indoor air quality (IAQ) monitoring was conducted in nine environments (three cabins, buffet, gym, bar, restaurant, pub and theatre), on board a cruise ship voyaging across the UK and EU, with the study conducted in the framework of the EU HEALTHY SAILING project. CO2 concentrations, temperature and relative humidity (RH) were simultaneously monitored to investigate thermal characteristics and effectiveness of ventilation performance. Results show a slightly higher RH of 68.2±5.3% aboard compared to ASHRAE and ISO recommended targets, with temperature recorded at 22.3±1.4°C. Generally, good IAQ (<1000ppm) was measured with CO2 mainly varying between 400 and 1200ppm. The estimated air change rates (ACH) and ventilation rates (VR) implied sufficient ventilation was provided in most locations, and the theatre (VR: 86Ls-1person-1) and cabins (VR: >20Ls-1person-1) were highly over-ventilated. Dining areas including the pub and restaurant recorded high CO2 concentrations (>2000ppm) potentially due to higher footfall (0.6person m-2 and 0.4person m-2) and limited ACH (2.3h-1 and 0.8h-1), indicating a potential risk of infection; these areas should be prioritised for improvement. The IAQ and probability of infection indicate there is an opportunity for energy saving by lowering hotel load for the theatre and cabins and achieving the minimum acceptable VR (10Ls-1person-1) for occupants' comfort and disease control. Our study produced a first-time dataset from a sailing cruise ship's ventilated areas and provided evidence that can inform guidelines about the optimisation of ventilation operations in large passenger ships, contributing to respiratory health, infection control and energy efficiency aboard.

Responses of invasive and native plant species to drought stress and elevated CO2 concentrations: a meta-analysis

Superior trait responses of invasive plant species to their native counterparts determine invasion success under various environmental conditions. To date, numerous experimental studies have compared the physiological and growth trait responses of invasive plant species to native ones in simulated drought or CO2 enrichment conditions; however, these studies have not recently been summarised. Here, we conducted a global meta-analysis using 48 experimental studies to determine whether there are generalisable differences between invasive and native plant species in terms of their physiological and growth trait responses to drought and elevated CO2 and which traits potentially facilitate plant invasion in these conditions. The results indicate that the magnitude of responses do not differ substantially between invasives and natives for most traits under drought or elevated CO2. Under drought stress, the photosynthetic rate, stomatal conductance, shoot biomass and total biomass decreased in both plant groups, supporting the contention that plants, irrespective of their origin, are negatively affected in water-limited environments. By contrast, we found that elevated CO2 increased water-use efficiency, shoot biomass and total biomass and decreased stomatal conductance in both invasives and natives, indicating that both plant groups grow vigorously in such conditions. Compared with estimates for natives, invasives were taller and invested more biomass to roots under drought and showed greater allocation to shoot biomass under elevated CO2. Although there were no substantial differences in the magnitude of responses in most studied traits, the differential growth responses in invasives may confer an advantage over natives under decreased water availability and high CO2 concentrations.

Arsenic in water from the Bystre Thrust-Sheet (Outer Carpathians, Poland): Geological and environmental implications

The article focuses on the physicochemical parameters of water in streams, springs, boreholes, and intakes from the Bystre Thrust-Sheet (the Silesian Nappe, Fore-Dukla Zone), the only area in the Polish segment of the Outer Carpathians where arsenic minerals occur. These waters are characterized by the presence of arsenic, lithium, mercury, barium, strontium and usually high CO2 concentrations. The study aimed to determine the range of the geochemical anomaly of arsenic in water. An important aspect was to determine the origin of As and link its presence with the content of ions of other chemical elements dissolved in water. The sampling points were designated based on geological maps with a particular emphasis on the occurrence of tectonic dislocations and the configuration of the river network. In the selected places 47 samples of water were taken, and various elements were determined. Then, the range of occurrence of various types of water that differed from the average concentrations of selected ions was analysed. The potential relationship between the chemical composition of water and the geology of the Bystre Thrust-Sheet was also discussed. The high concentrations of arsenic were found only in springs and boreholes. In flowing waters, these concentrations quickly decreased due to dilution or precipitation and binding with the solid phase. Relatively high (max. 378.72 μg/L) arsenic concentration, which significantly exceeded the permissible value (50 μg/L), was detected in the Bystre 1 borehole. This water has a pH value of 7.85 indicating its alkaline nature. When considering water use for health purposes, it is necessary to monitor its arsenic content. The conditions prevailing in waters, mainly high pH, favour the immobilization of metals in sediments and suspended matter. The lower concentrations of arsenic in flowing waters may be attributed to the strongly calcareous nature of the Cieszyn beds which act as a natural barrier, limiting the migration of arsenic beyond the Bystre Thrust-Sheet.

Microbial diversity and biogeochemical interactions in the seismically active and CO2- rich Eger Rift ecosystem.

The Eger Rift subsurface is characterized by frequent seismic activity and consistently high CO2 concentrations, making it a unique deep biosphere ecosystem and a suitable site to study the interactions between volcanism, tectonics, and microbiological activity. Pulses of geogenic H2 during earthquakes may provide substrates for methanogenic and chemolithoautotrophic processes, but very little is currently known about the role of subsurface microorganisms and their cellular processes in this type of environment. To assess the impact of geologic activity on microbial life, we analyzed the geological, geochemical, and microbiological composition of rock and sediment samples from a 238m deep drill core, running across six lithostratigraphic zones. We evaluated the diversity and distribution of bacterial and archaeal communities. Our investigation revealed a distinct low-biomass community, with a surprisingly diverse archaeal population, providing strong support that methanogenic archaea reside in the Eger subsurface. Geochemical analysis demonstrated that ion concentrations (mostly sodium and sulfate) were highest in sediments from 50 to 100m depth and in weathered rock below 200m, indicating an elevated potential for ion solution in these areas. Microbial communities were dominated by common soil and water bacteria. Together with the occurrence of freshwater cyanobacteria at specific depths, these observations emphasize the heterogenous character of the sediments and are indicators for vertical groundwater movement across the Eger Rift subsurface. Our investigations also found evidence for anaerobic, autotrophic, and acidophilic communities in Eger Rift sediments, as sulfur-cycling taxa like Thiohalophilus and Desulfosporosinus were specifically enriched at depths below 100m. The detection of methanogenic, halophilic, and ammonia-oxidizing archaeal populations demonstrate that the unique features of the Eger Rift subsurface environment provide the foundation for diverse types of microbial life, including the microbial utilization of geologically derived CO2 and, when available, H2, as a primary energy source.

Functional Near-Infrared Spectroscopy Analysis of Cerebral Physiological Changes in Response to Atmospheric Gas Concentrations

Compared with other organs in the body, the human brain is extremely sensitive to changes in O2 and CO2 levels. This study applied functional near-infrared spectroscopy (fNIRS) to analyze the changes in cerebral oxygen saturation (COS) and hemoglobin (Hb) concentrations in response to various atmospheric gas concentrations and investigate their effects on brain function. Twenty-nine adults were exposed to four gas conditions, namely atmospheric concentration (C1), high O2 concentration (C2), high CO2 concentration (C3), and high O2 and CO2 concentrations (C4). Changes in COS and Hb concentrations were measured using fNIRS, whereas heart rate (HR) and percutaneous oxygen saturation (SpO2) were measured using a patient monitor. COS, oxy-Hb (HbO), and total-Hb (HbT) increased progressively from C1 to C4, whereas deoxy-Hb (HbR) exhibited a decreasing trend. Moreover, the COS and Hb concentrations were more strongly influenced by high CO2 levels than by high O2 levels. High O2 concentrations increased the blood O2 saturation, whereas high CO2 concentrations increased blood flow as a physiological response, enhancing O2 delivery to the brain. Additionally, HR and SpO2 increased at high CO2 concentrations. However, at high O2 concentrations providing a sufficient O2 supply, SpO2 increased while HR decreased. Therefore, adjusting the concentrations of CO2 and O2 may improve cerebral blood flow and change brain function, supporting cerebrovascular health and preventing related diseases.

Heterogeneity in Diameters of Protein Fibrils and Chitosan for a High CO2/O2 Selectivity and Desired Mechanical Properties of Edible Bioplastic Films.

Edible bioplastics offer a possible approach with great potential to address the challenges of plastic and microplastic crisis and the issue of food waste. In the present study, in situ, induction of fibrillation of legume proteins within chitosan matrix is found to form edible bioplastic films with a high CO2/O2 selectivity coefficient of ≈130. Desirable mechanical properties, including a high elongation at break of ≈230%, are realized to fabricate shopping bags, which can be filled with 5kg of fruits. An atmosphere with a high CO2 content and low O2 concentration is spontaneously achieved after strawberries are packaged with the films and ≈85% of the fruits are edible after 9 days. The contents of CO2 in the equilibrium state and the percent of edible fruits are positively correlated with the CO2/O2 selectivity of the films. By comparison of the edible bioplastic films made from mung bean protein (MP) and pea protein (PP), the fibrillation capability of legume proteins and the heterogeneity in polydisperse diameters of the protein fibrils and chitosan are demonstrated to make great contributions to the dense microstructure, leading to the strong mechanical properties and high gas selectivity of the films. The structure-property relationship is elucidated for high-performance bioplastics films.

Bio‐MOF‐11 Derived Amorphous Cobalt Hollow Nanospheres to Access Bioactive Quinazolinone Scaffolds and Aromatic Amines

AbstractA facile synthetic strategy is reported to afford bioactive quinazolinones and aromatic amines by employing amorphous cobalt hollow nanospheres (Co HNS) derived from a Bio‐MOF, cobalt adeninate, as a catalyst. Modulated electron states of the amorphous cobalt with a high concentration of surficial active sites and Co–N sites enhance the intrinsic catalytic activity while the support, activated carbon, facilitates the formation of hollow structure.