High Levels Of Carbon Dioxide Research Articles

Evaluating Indoor Air Quality in Residential Environments: A Study of PM2.5 and CO2 Dynamics Using Low-Cost Sensors

Indoor air quality (IAQ) poses a significant public health concern, and exposures to high levels of fine particulate matter (PM2.5) and carbon dioxide (CO2) could have detrimental health impacts. This study focused on assessing the indoor air pollutants in a residential house located in the town of Mission, Hidalgo County, South Texas, USA. The PM2.5 and CO2 were monitored indoors: the kitchen and the bedroom. This investigation also aimed to elucidate the effects of household activities such as cooking and human occupancy on these pollutants. Low-cost sensors (LCSs) from TSI AirAssure™ were used in this study. They were deployed within the breathing zone at approximately 1.5 m above the ground. Calibration of the low-cost sensors against Federal Equivalent Method (FEM) instruments was undertaken using a multiple linear regression method (MLR) model to improve the data accuracy. The indoor PM2.5 levels were significantly influenced by cooking activities, with the peak PM2.5 concentrations reaching up to 118.45 μg/m3. The CO2 levels in the bedroom increased during the occupant’s sleeping period, reaching as high as 1149.73 ppm. The health risk assessment was assessed through toxicity potential (TP) calculations for the PM2.5 concentrations. TP values of 0.21 and 0.20 were obtained in the kitchen and bedroom, respectively. The TP values were below the health hazard threshold (i.e., TP < 1). These low TP values could be attributed to the use of electric stoves and efficient ventilation systems. This research highlights the effectiveness of low-cost sensors for continuous IAQ monitoring and helps promote better awareness of and necessary interventions for salubrious indoor microenvironments.

Impact of Agricultural Activities on Climate Change: A Review of Greenhouse Gas Emission Patterns in Field Crop Systems.

This review paper synthesizes the current understanding of greenhouse gas (GHG) emissions from field cropping systems. It examines the key factors influencing GHG emissions, including crop type, management practices, and soil conditions. The review highlights the variability in GHG emissions across different cropping systems. Conventional tillage systems generally emit higher levels of carbon dioxide (CO2) and nitrous oxide (N2O) than no-till or reduced tillage systems. Crop rotation, cover cropping, and residue management can significantly reduce GHG emissions by improving soil carbon sequestration and reducing nitrogen fertilizer requirements. The paper also discusses the challenges and opportunities for mitigating GHG emissions in field cropping systems. Precision agriculture techniques, such as variable rate application of fertilizers and water, can optimize crop production while minimizing environmental impacts. Agroforestry systems, which integrate trees and crops, offer the potential for carbon sequestration and reducing N2O emissions. This review provides insights into the latest research on GHG emissions from field cropping systems and identifies areas for further study. It emphasizes the importance of adopting sustainable management practices to reduce GHG emissions and enhance the environmental sustainability of agricultural systems.

Control of breathing in preterm infants on incubator oxygen or nasal cannula oxygen.

Incubator oxygen may improve respiratory stability in preterm infants compared with nasal cannula oxygen. Single center randomized trial of infants <29 weeks' gestation on supplemental oxygen at ≥32 weeks' postmenstrual age. Infants were crossed-over every 24 hours for 96 hours between incubator oxygen and nasal cannula ≤1.0 L/kg/min. We measured episodes of intermittent hypoxemia (oxygen saturations (SpO2) < 85% ≥10 seconds), bradycardia, cerebral and abdominal hypoxemia, and end-tidal carbon dioxide. We enrolled 25 infants with a gestational age of 26 weeks 4 days±15 days (mean ± SD) and birth weight 805 ± 202 grams. There were no differences in episodes of intermittent hypoxemia, bradycardia, or cerebral hypoxemia between groups. There were fewer episodes of abdominal hypoxemia <40% ≥10 seconds with incubator oxygen compared with nasal cannula (132 ± 130 versus 158 ± 125; p < 0.01). Time with SpO2 < 85% and abdominal hypoxemia was lower among infants on incubator oxygen. Carbon dioxide values were higher while on incubator oxygen (41 ± 11 versus 36 ± 10 mmHg; p < 0.02). There was no difference in intermittent hypoxemia between incubator and nasal cannula oxygen among preterm infants on supplemental oxygen. Infants had higher levels of carbon dioxide while on incubator oxygen, which may have improved some measures of respiratory stability. CLINCALTRIALS. NCT03333174 and NCT03174301. In this randomized cross-over trial of preterm infants on supplemental oxygen, incubator oxygen did not decrease episodes of intermittent hypoxemia compared with nasal cannula oxygen. Incubator oxygen reduced time with oxygen saturations less than 85%, reduced abdominal hypoxemia, and increased carbon dioxide levels. Differences in measures of respiratory stability on incubator oxygen may be partly due to higher carbon dioxide levels compared with nasal cannula oxygen. The mode of supplemental oxygen administration may impact control of breathing in preterm infants through its effect on hypopharyngeal oxygen stability and carbon dioxide levels.

IMPACT OF ENRICHED CO2 IN MODIFIED ATMOSPHERE PACKAGING ON THE PRESERVATION OF “PALMARITAS” STRAWBERRIES AND THE EXTENSION OF THEIR SHELF LIFE

This study evaluated the effect of modified atmospheres (MAPs) with low oxygen levels (2.5%) and high carbon dioxide levels (from 5 to 20%) on strawberries. During 12 days of storage at 4°C, various quality and chemical content parameters were evaluated. These including decay, color, weight loss, firmness, total soluble solids, total polyphenols, anthocyanins, and flavonoids, as well as antioxidant capacity and individual phenolic compounds (quercetin, caffeic acid, gallic acid, (-) epicatechin, and p-coumaric acid). Results showed that high CO2 levels had a positive impact on strawberry preservation: weight loss was reduced, anthocyanin content increased, decay and softening were significantly reduced, and vitamin C content was maintained. At the same time, these high concentrations of CO2 did not affect sugar content, color, antioxidant capacity, total phenolic compounds, or total flavonoid compounds of strawberries. A storage time of 12 days at 4°C, under MAP with an initial gas condition of 2.5% O2 + 15% CO2 + 82.5% N2 or 2.5% O2 + 20% CO2 + 77.5% N2, was found to be ideal for preserving the quality of fresh strawberries.

Identification of genes used by Escherichia coli to mitigate climatic stress conditions

IntroductionIncreasing temperature and elevated atmospheric carbon dioxide levels could impact the survival of stress-adapted bacteria. Method and resultsIn this study, RNA sequencing was performed to quantify Escherichia coli BL21 (DE3) gene expression in culture media under environmental temperature (27 °C and 42 °C) and carbon dioxide (0.2 % and 6 % v/v) conditions. Differential gene expression analysis between low temperature and different carbon dioxide conditions revealed up-regulated genes such as ldtC and bioA, optimising cell wall integrity and nutrient uptake. While, the downregulation of genes such as malK suggested a metabolic adaptation. Low temperature and high carbon dioxide levels enhanced bacterial tolerance to environmental stress. Under optimal temperatures, Escherichia coli adapts through various metabolic pathways while engaging in different processes at low temperatures and carbon dioxide levels, with temperature having a greater impact on gene expression than carbon dioxide levels. This study shows that complex metabolic activities are activated when both temperatures and carbon dioxide levels are combinsed, affecting antimicrobial resistance, nutrient acquisition, and adaptation strategies. ConclusionEach condition exhibited mechanisms to enhance cellular resilience and adaptation to stress, focusing on cellular integrity, optimising energy utilisation, and activating stress response pathways. Impact statementThe findings stress the importance of continued research to understand the implications of climate change on microbial transcriptomes comprehensively.

The expected changes with different periods of home-based resistance exercise in patients with chronic kidney disease.

The comprehensive impact of prolonged home-based resistance training on individuals grappling with chronic kidney disease (CKD) have yet to be fully elucidated. This study aimed to explore the outcomes of varying exercise durations on physical performance, nutritional status, and kidney function within this specific population, encompassing patients undergoing dialysis and those affected by severe sarcopenia. This was a 1-year observational double cohort study following a 52-week longitudinal design, we enrolled 101 adult CKD outpatients. These participants were divided into two groups: the continuous group, comprising individuals who consistently exercised for over 6 months, and the interrupted group, which included those who did not sustain regular exercise for the same duration. The exercise regimen involved resistance exercises conducted at least 3 to 5 days per week, involving activities like lifting dumbbells and executing weighted wall squats. Physical activity assessments and biochemical blood tests were conducted at weeks 0, 4, 16, 28, 40, and 52 for all participants. The continuous exercise group exhibited better handgrip strength and sit-to-stand movement compared to the interrupted group. Their estimated glomerular filtration rate stayed steady while the interrupted group was declined. Additionally, those who exercised consistently had better metabolism: higher carbon dioxide levels, increased albumin, better nutritional scores, and lower levels of blood urea nitrogen, creatinine, fasting blood glucose, and body weight. Subsequent adjustments for potential confounding factors continued to show improved physical performance and kidney function over time. Our findings indicate the advantageous impact of extended resistance exercise training on overall health of CKD patients, even those on dialysis or with severe sarcopenia. Dedication to this exercise routine could improve kidney function, metabolism, and physical abilities in these patients.

Anterior palatoplasty as a treatment for mild and moderate obstructive sleep apnea: our experience

Abstract BACKGROUND. Obstructive sleep apnea (OSA) is characterized by frequent episodes of breathing cessation during sleep, resulting in low oxygen and high carbon dioxide levels, leading to daytime sleepnes, cognitive issues, and increased cardiovascular risk. The objective of this study was to assess the effectiveness of the anterior palatoplasty (AP) procedure in the treatment of patients with mild and moderate obstructive sleep apnea. MATERIAL AND METHODS. Sixteen patients diagnosed with mild and moderate OSA underwent AP in our clinic between 2021-2023. All patients were &gt; 18 years old, body mass index &lt; 30, with an apnea-hypopnea index (AHI) from 10 to 40 and disfunction of the velopharyngeal or of the retropalatal space. Patients underwent a one-night polysomnography examination prior to the surgical procedure, as well as six months after the procedure. Additionally, patients were asked to complete the Epworth Sleepiness Scale (ESS) both prior to and six months following the surgery. The procedure was done under general anaesthesia and involved AP surgery with or without reducing of the uvula. RESULTS. The average of total AHI values decreased from 28.89 per hour prior to surgery to 11.14 per hour six months after surgery. The oxygen desaturation index decreased after surgery with 2.57%. ESS scores of patients also decreased from 10.40 to 7.80 and all patients felt less tired. CONCLUSION. We believe that AP is an effective technique in the treatment of mild and moderate OSA caused by a disfunction of the velopharyngeal or retropalatal space. Additionally, we consider that AP is linked with a lower incidence of post-surgical complications compared to other surgical options.

Modified mesoporous silica derived from bamboo leaf using cetyltrimethylammonium bromide and 3-aminopropyl triethoxysilane as CO2 adsorbentinbiogas purification.

The calorific value of post-fermentation biogas is a way down below standard and quite low due to the presence of high amount level of carbon dioxide (CO2) biogas mixture. Therefore, it raises the need to process the biogas, separating it from CO2 in order to obtain high-purity biogas as well as to maximize its calorific value. One widely available material that can be used as a sustainable carbon capture adsorbent is silica extracted from bamboo leaves. However, so that silica can act as CO2 adsorber, it is necessary to modify the surface of silica with CTAB and APTES (3-aminopropyl triethoxysilane). In this study, 2-stage method was carried out, namely preparation of mesoporous silica and surface modification using APTES on the mesoporous silica. Experiments in synthesizing APTES-modified silica were obtained by varying its composition: CTAB (1.5-5%w), (HCl 1.5-5 N), and APTES (10-30%). A central composite design (CCD) was employed in exploring the interaction between all variables and also performed for the optimization. Through analysis of variance, it shows that optimum CO2 adsorption capacity reaches 47.02mgg-1, by applying 4.98% of CTAB, 4.28N of HCl and 10.08% of APTES. Pseudo-second-order kinetic and Redlich-Peterson isotherm models are more representative to show the adsorption behavior of CO2 into the modified silica. The results show that the modified silica with APTES shows a prospective application of silica for CO2 removal from biogas.

Atmosphere modification system for respiration analysis of recalcitrant seeds during storage

Abstract: The modification of atmosphere composition is a strategy to prolong the storage of organisms susceptible to senescence. Atmospheres with high levels of carbon dioxide could be applied to prolong the viability of recalcitrant seeds, which are in a constant process of deterioration due to intense metabolic activity. However, there is a need to develop methods that allow the standardized generation of these modified atmospheres to isolate the effect of low oxygen from high carbon dioxide. In this study, the generation of modified atmospheres was carried out by experiments with insufflated gas (IG) or compensated vacuum (CV), on recalcitrant Inga vera embryos as an experimental model. In IG, CO2 and N2 were uninterruptedly injected into a mixing chamber, in which the gases underwent turbulence to be homogenized and subsequently applied to the flasks where the embryos were incubated. In CV, the embryos were placed in flasks, from which a fraction of the air present inside was removed, and subsequently, the gases of interest were injected in defined fractions. The CV method proved to be more efficient and it was possible to restrict the respiratory metabolism of the Inga vera embryos by reducing respiration with the increase in carbon dioxide applied exogenously.

Study of calcium carbonate scaling on steel using a high salinity brine simulating a pre-salt produced water

In Brazilian pre-salt production, high carbon dioxide (CO2) levels in the associated gas, high salinity in the water, and high levels of calcium ions cause problems related to corrosion and scale. In practice, the scaling process already begins in the formation and near the wellbore region. However, this work has addressed this issue only on a steel surface, representing what can occur in oil production tubings and equipment since the build-up of these products in the internal walls can also impact the production flow guarantee. Parameters related to the substrate and the environment can influence calcium carbonate (CaCO3) precipitation mechanisms. In this study, the effect of steel surface roughness on calcium carbonate scaling experiments has been studied in a high salinity brine containing sodium bicarbonate (NaHCO3) and calcium chloride (CaCl2), simulating pre-salt produced water and under flow conditions. The scaling tests were carried out with a set-up composed of a peristaltic pump to recirculate the test solution through a flow cell. The scale build-up was analysed by using techniques such as Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersion X-ray Spectroscopy (EDS). For tests carried out in 3 h, the smoother surfaces had lower adhesion of calcium carbonate than surfaces with higher roughness. Lepidocrocite and rokuehnite, which are corrosion products, were formed in the substrates with higher roughness values, promoting aragonite formation. This work demonstrates that roughness influences calcium carbonate scale formation under flow conditions, besides affecting the calcium carbonate polymorphs associated with the corrosion process.

Modelling a CO2 meter for a petroleum multiphase mixture at subsea conditions

Measuring high levels of carbon dioxide (CO2) in Brazilian pre-salt production flows remains a considerable technological challenge. The complexity of the three-phase flow and the variable CO2 solubility within each phase poses difficulties in accurately measuring CO2 in this scenario. Moreover, existing CO2 measurement techniques designed for single-phase fluids prove insufficient under mixed-phase conditions. This study proposes a methodology for a simple CO2 meter capable of determining the CO2 content in an oil and gas production stream. The proposed meter operates by analyzing the pressure change during a heating assay of an imprisoned sample. A computational model was developed in the ASPEN HYSYS® process simulator with the Peng-Robinson Equation of State to calculate the mixture properties emulating the isochoric process in the meter under different CO2 levels and initial conditions. The modelling results indicate that the pressure-temperature (P-T) behavior exhibits linearity with a slope that increases with higher CO2 content, which is characteristic of many pre-salt production fields. The model successfully reproduced published experimental data for an isochoric process.

Fungi under Modified Atmosphere-The Effects of CO2 Stress on Cell Membranes and Description of New Yeast Stenotrophomyces fumitolerans gen. nov., sp. nov.

High levels of carbon dioxide are known to inhibit the growth of microorganisms. A total of twenty strains of filamentous fungi and yeasts were isolated from habitats with enriched carbon dioxide concentration. Most strains were derived from modified atmosphere packed (MAP) food products or mofettes and were cultivated under an atmosphere of 20% CO2 and 80% O2. The influence of CO2 on fungal cell membrane fatty acid profiles was examined in this study. Major changes were the increase in linolenic acid (C18:3 cis 9, 12, 15) and, additionally in most strains, linoleic acid (C18:2 cis 9, 12) with a maximum of 24.8%, at the expense of oleic (C18:1 cis 9), palmitic (C16:0), palmitoleic (C16:1 cis 9) and stearic acid (C18:0). The degree of fatty acid unsaturation increased for all of the strains in the study, which consequently led to lower melting temperatures of the cell membranes after incubation with elevated levels of CO2, indicating fluidization of the membrane and a potential membrane malfunction. Growth was reduced in 18 out of 20 strains in laboratory experiments and a change in pigmentation was observed in several strains. Two of the isolated strains, strain WT5 and strain WR1, were found to represent a hitherto undescribed yeast for which the new genus and species Stenotrophomyces fumitolerans (MB# 849906) is proposed.

Production of Biohydrogen from Microalgae Biomass after Wastewater Treatment and Air Purification from CO2

This article explores the feasibility of producing biohydrogen from microalgae following their use in wastewater purification from food industry facilities and the removal of high levels of carbon dioxide (CO2) from the air. The authors investigated various methods for disrupting the cell membranes of microalgae and their impact on biohydrogen yield. The microalgae biomass obtained after wastewater and air purification underwent pre-treatment using physicochemical and chemical methods, including microwave radiation, acid treatment, and thermal treatment. The highest hydrogen production occurred during thermal and acid treatments of biomass with the addition of starch (44.24 mL/L of suspension). The use of microwave radiation for processing did not yield significant results. A comparison of the biohydrogen values obtained from untreated and treated biomass revealed that treatment enhances biohydrogen yield.

Permissive hypercapnia and oxygenation impairment in premature ventilated infants

AimIn permissive hypercapnia high levels of carbon dioxide (CO2) are tolerated in ventilated preterm infants to minimise lung injury, but hypercapnia could directly impair oxygenation. We aimed to quantify the association of elevated CO2 with oxygenation impairment in preterm infants by measuring the right-to-left shunt and the ventilation/perfusion (VA/Q) ratio. MethodsPre-existing datasets from preterm infants during the acute phase of respiratory distress syndrome or with evolving or established bronchopulmonary dysplasia were analysed. Non-invasive paired measurements of the fraction of inspired oxygen (FIO2) and transcutaneous oxygen saturation (SpO2) were used to calculate the degree of right-to-left shunt, right shift of the FIO2 versus SpO2 curve and the VA/Q. ResultsA total of 75 infants (43 male) with a median (IQR) gestational age of 26.4 (24.7–27.7) weeks were studied at 7 (2–31) days. Thirty-six infants (48 %) had an arterial partial pressure of CO2 (PaCO2) above 6 kPa. The PaCO2 was independently associated with the right shift of the curve [adjusted p < 0.001, unstandardised coefficient; 2.26, 95 % CI: 1.51–2.95] and the right-to-left shunt [adjusted p = 0.016, unstandardised coefficient; 1.86, 95 % CI: 0.36–3.36] after adjusting for confounders. An increase of the PaCO2 from 5 to 8 kPa, corresponded to a right shift of the curve of 20.2 kPa or a decrease in the VA/Q from 0.66 to 0.24. ConclusionsIncreased carbon dioxide levels were significantly associated with impaired oxygenation in preterm infants with respiratory distress syndrome or bronchopulmonary dysplasia.

Sunflower physiological adjustments to elevated CO2 and temperature do not improve reproductive performance and productivity

High levels of carbon dioxide (eCO2) and temperature (eT) affect the physiological performance of sunflowers, but the full extent of their influence on productivity and floral traits remains to be disclosed. Here, we show that eT increased the maximum rate of carboxylation, maximum electron transport capacity, and net rate of triose-phosphate production, indicating enhanced carbon fixation. Although eT increased reactive oxygen species (ROS) concentration in the leaves, no signs of lipid peroxidation in cellular membranes were detected, and plants activated antioxidant systems to counteract the increase in ROS. Moreover, under eT, sunflower pollen exhibited higher amounts of Fe and Zn but also experienced reduced development and productivity due to increased production of empty seeds. In response to eCO2, sunflowers reduced stomatal conductance, limiting water loss, contributing to increased water use efficiency and enhanced photosynthesis. Additionally, under eCO2, sunflowers displayed pollen with higher levels of P, increased biomass gain, and productivity. Lastly, the isolated effects of eCO2 and eT had contrasting impacts on inflorescence size, but the combination of these factors did not result in changes compared to current conditions. However, both factors contributed to increased carotenoid content in ray florets. In contrast, the eCO2eT combination enhanced photosynthesis, flavonoid production in ray florets, and reduced the amount of K and Cu in pollen. In conclusion, eCO2eT improved the physiological performance of sunflowers, but this was not accompanied by increased growth and productivity. The reduction in seed production in sunflowers can have negative impacts on ecology, genetic diversity, and agricultural economy. While eCO2eT did not affect sunflower inflorescence size, they did affect petal pigmentation and pollen quality, which can have significant implications for pollinator health. Understanding the full extent of eCO2eT effects poses a challenge for developing effective mitigation strategies and optimizing agricultural sustainability in the face of climate change.

New Developments in Climate Change, Air Pollution, Pollen Allergy, and Interaction with SARS-CoV-2

In recent years, the environmental impacts of climate change have become increasingly evident. Extreme meteorological events are influenced by climate change, which also alter the magnitude and pattern of precipitations and winds. Climate change can have a particularly negative impact on respiratory health, which can lead to the emergence of asthma and allergic respiratory illnesses. Pollen is one of the main components of the atmospheric bioaerosol and is able to induce allergic symptoms in certain subjects. Climate change affects the onset, length, and severity of the pollen season, with effects on pollen allergy. Higher levels of carbon dioxide (CO2) can lead to enhanced photosynthesis and a higher pollen production in plants. Pollen grains can also interact with air pollutants and be affected by thunderstorms and other extreme events, exacerbating the insurgence of respiratory diseases such as allergic rhinitis and asthma. The consequences of climate change might also favor the spreading of pandemics, such as the COVID-19 one.

Assessing the growth-stimulating effect of tea waste compost in urban agriculture while identifying the benefits of household waste carbon dioxide

Tea is a globally popular beverage, leading to a significant accumulation of municipal waste. This study investigated the effects of tea waste compost on the growth traits of Raphanus sativus L. or radish while exploring the contribution of clean source carbon dioxide to sustainable production. The research team gathered the tea waste from urban households and allowed it to decompose for four months. Certain volumes of the tea waste compost ranging from 0% to 75% were mixed with locally available loamy textured garden soil (v/v). To simulate the impact of carbon dioxide waste from urban households on plant growth, the first greenhouse was enriched with carbon dioxide to reach elevated concentrations of 1500 ± 100 ppm, while the second greenhouse was maintained at the ambient level of 500 ± 20 ppm. The optimal growth temperature of both greenhouses was supplied with electricity. Using a split plot design, the effects of normal and elevated carbon dioxide levels, different volumes of tea waste compost, and the combined effect of tea waste compost and carbon dioxide levels on growth traits were investigated. The results showed that the elevated carbon dioxide level negatively influences the radish yield, biomass accumulation, and vegetative growth parameters. However, the tea waste compost improves growth traits with increasing volumes in garden soil from 0% to 75% (v/v). In the media containing 75% of tea waste compost, the elevated carbon dioxide level has the same effect as the normal level on growth traits, however, positive effects on total fresh weight but negative effects on measures of total dry weight, leaf dry weight, and total leaf area. These results show that the highest volume of tea waste compost ideally supports the growth of radish, which is mainly related to its high nitrogen content. The high and normal carbon dioxide levels in this volume are unable to dominate each other in terms of growth promotion. However, to reduce the amount of carbon dioxide emitted from houses and to produce fresh products, the waste carbon dioxide of urban houses should be transferred to the greenhouse to provide radishes with higher carbon dioxide levels during photosynthesis. Renewable energy sources such as solar or wind-generated electricitycan be used to increase the temperature to the optimal level. This production method should be evaluated in future studies for other horticultural crops that prefer high carbon dioxide levels.

The Association between Indoor Carbon Dioxide Reduction by Plants and Health Effects

Residents and workers exposure to high carbon dioxide (CO2) levels in buildings may cause headache, dyspnea, fatigue, or drowsiness. However, the effect of plants on in-building CO2 reduction and adverse effect relief is largely unknown. We recruited 36 healthy participants from an office room with plants and 32 healthy participants from another office room without plant in the same office building in Taipei. The participants in the office room with plants during 2020 would move to the office room without plant in 2021. The twelve repeated measurements per year of CO2, fine particles (PM2.5), total volatile organic compounds (TVOCs), blood pressure (BP), serum CO2 (TCO2), and four rating questions of headache, dyspnea, fatigue, and drowsiness were obtained for each participant. The statistical results showed that levels of drowsiness and systolic BP were significantly lower among participants in the office room with plants compared to those in the office room without plants by <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"> <mi>t</mi> </math> -test and paired <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2"> <mi>t</mi> </math> -test. The associations between increased indoor CO2 and increased serum CO2 were observed in the office room with plants (1.32%) and without plant (4.52%) by mixed-effects models. Also, the associations between indoor CO2 and drowsiness were observed in office rooms (with plants: 14.57%; without plant: 3.82%). The conclusion of the present study is that plants in office environment can reduce CO2 levels and may lower CO2-related health effects.

An integrated multi-level analysis reveals learning-memory deficits and synaptic dysfunction in the rat model exposure to austere environment

Austere environment existing in tank, submarine and vessel has many risk factors including high temperature and humidity, confinement, noise, hypoxia, and high level of carbon dioxide, which may cause depression and cognitive impairment. However, the underlying mechanism is not fully understood yet. We attempt to investigate the effects of austere environment (AE) on emotion and cognitive function in a rodent model. After 21 days of AE stress, the rats exhibit depressive-like behavior and cognitive impairment. Compared with control group, the glucose metabolic level of the hippocampus is significantly decreased using whole-brain positron emission tomography (PET) imaging, and the density of dendritic spines of the hippocampus is remarkably reduced in AE group. Then, we employ a label-free quantitative proteomics strategy to investigate the differentially abundant proteins in rats' hippocampus. It is striking that the differentially abundant proteins annotated by KEGG enrich in oxidative phosphorylation pathway, synaptic vesicle cycle pathway and glutamatergic synapses pathway. The synaptic vesicle transport related proteins (Syntaxin-1A, Synaptogyrin-1 and SV-2) are down-regulated, resulting in the accumulation of intracellular glutamate. Furthermore, the concentration of hydrogen peroxide and malondialdehyde is increased while the activity of superoxide dismutase and complex I and IV of mitochondria is decreased, indicating that oxidative damage to hippocampal synapses is associated with the cognitive decline. The results of this study offer direct evidence, for the first time, that austere environment can substantially cause learning and memory deficits and synaptic dysfunction in a rodent model via behavioral assessments, PET imaging, label-free proteomics, and oxidative stress tests. SignificanceThe incidence of depression and cognitive decline in military occupations (for example, tanker and submariner) is significantly higher than that of global population. In the present study, we first established novel model to simulate the coexisting risk factors in the austere environment. The results of this study offer the direct evidences, for the first time, that the austere environment can substantially cause learning and memory deficits by altering plasticity of the synaptic transmission in a rodent model via proteomic strategy, PET imaging, oxidative stress and behavioral assessments. These findings provide valuable information to better understand the mechanisms of cognitive impairment.

How voles adapt to subterranean lifestyle: Insights from RNA-seq

Life under the earth surface is highly challenging and associated with a number of morphological, physiological and behavioral modifications. Subterranean niche protects animals from predators, fluctuations in environmental parameters, but is characterized by high levels of carbon dioxide and low levels of oxygen and implies high energy requirements associated with burrowing. Moreover, it lacks most of the sensory inputs available above ground. The current study describes results from RNA-seq analysis of four subterranean voles from subfamily Arvicolinae:Prometheomys schaposchnikowi,Ellobius lutescens,Terricola subterraneus, andLasiopodomys mandarinus. Original RNA-seq data were obtained for eight species, for nine species, SRA data were downloaded from the NCBI SRA database. Additionally assembled transcriptomes of Mynomes ochrogaster and Cricetulus griseus were included in the analysis. We searched for the selection signatures and parallel amino acid substitutions in a total of 19 species. Even within this limited data set, we found significant changes ofdN/dSratio by free-ratio model analysis for subterranean Arvicolinae. Parallel substitutions were detected in genesRAD23BandPYCR2. These genes are associated with DNA repair processes and response to oxidative stress. Similar substitutions were discovered in theRAD23genes for highly specialized subterraneanHeterocephalus glaberandFukomys damarensis. The most pronounced signatures of adaptive evolution related to subterranean niche within species of Arvicolinae subfamily were detected forEllobius lutescens. Our results suggest that genomic adaptations can occur very quickly so far as the amount of selection signatures was found to be compliant with the degree of specialization to the subterranean niche and independent from the evolutionary age of the taxon. We found that the number of genomic signatures of selection does not depend on the age of the taxon, but is positively correlated with the degree of specialization to the subterranean niche.