Room Air Research Articles

Recovery of ventilatory and metabolic responses to hypoxia in neonatal rats after chronic hypoxia

Chronic hypoxia (CH) during postnatal development attenuates the hypoxic ventilatory response (HVR) in mammals, but there are conflicting reports on whether this plasticity is permanent or reversible. This study tested the hypothesis that CH-induced respiratory plasticity is reversible in neonatal rats and investigated whether the initial plasticity or recovery differs between sexes. Rat pups were exposed to 3 d of normobaric CH (12 % O2) beginning shortly after birth. Ventilation and metabolic CO2 production were then measured in normoxia and during an acute hypoxic challenge (12 % O2) immediately following CH and after 1, 4–5, and 7 d in room air. CH pups hyperventilated when returned to normoxia immediately following CH, but normoxic ventilation was similar to age-matched control rats within 7 d after return to room air. The early phase of the HVR (minute 1) was only blunted immediately following the CH exposure, while the late phase of the HVR (minute 15) remained blunted after 1 and 4–5 d in room air; recovery appeared complete by 7 d. However, when normalized to CO2 production, the late phase of the hypoxic response recovered within only 1 d. The initial blunting of the HVR and subsequent recovery were similar in female and male rats. Carotid body responses to hypoxia (in vitro) were also normal in CH pups after approximately one week in room air. Collectively, these data indicate that ventilatory and metabolic responses to hypoxia recover rapidly in both female and male neonatal rats once normoxia is restored following CH.

Chemical characterization of pellet stove ashes: Elemental fractionation of ashes results in volatile particles with high concentrations of cadmium and lead

Use of wood-based biomass for home heating has increased as a more sustainable and economical alternative to fossil fuel heating sources. However, concerns remain regarding particulate emissions and potential human health effects. Pellet stoves are very efficient combustion sources but still emit high particle numbers of nanoparticles into the environment and generate ash within the stove that could be an exposure source during cleaning. In this study we chemically characterize pellet ash collected from zones (upper and lower) from three stoves and determine the chemical composition of room air during cleaning events. Ash was acid digested using reverse aqua regia and microwave digestion and analyzed by ICP-MS. Indoor air was sampled using impingers before and during stove cleaning to assess ultrafine particulate release and exposure. Within the pellet stove different fractions of ash could be identified by color and macro-scale morphology. Ash fractions collected lower in the stove were predominantly calcium-based, 25 % by weight, and high in refractory trace elements, Fe, Cr, Mn and Ni. In contrast, ash collected higher in the stove was predominantly K and S based (25 and 5 % respectively) and had high concentrations of volatile elements Zn (0.4 %), Cd and Pb. Maximum Cd and Pb ash concentrations were 274 mg/kg and 807 mg/kg respectively corresponding to enrichment factors of 1581 and 870 compared to the respective pellets. Electron microscopy of the particles suggested that ash particles were agglomerates of smaller primary particles and EDS identified areas of high K and S concentration on the particles. Impinger studies of room air during cleaning showed an increase in K, S, Zn, Cd and Pb suggesting a mobilization of upper ash particles into room air upon stove cleaning.

Preoperative Atelectasis in Patients with Obesity Undergoing Bariatric Surgery: A Cross-Sectional Study.

Pulmonary atelectasis is present even before surgery in patients with obesity. We aimed to estimate the prevalence and extension of preoperative atelectasis in patients with obesity undergoing bariatric surgery and to determine if variation in preoperative Spo2 values in the seated position at room air is explained by the extent of atelectasis coverage in the supine position. This was a cross-sectional study in a single center specialized in laparoscopic bariatric surgery. Preoperative chest computed tomographies were reassessed by a senior radiologist to quantify the extent of atelectasis coverage as a percentage of total lung volume. Patients were classified as having atelectasis when the affection was ≥2.5%, to estimate the prevalence of atelectasis. Crude and adjusted prevalence ratios (aPRs) and odds ratios (aORs) were obtained to assess the relative prevalence of atelectasis and percentage coverage, respectively, with increasing obesity category. Inverse probability weighting was used to assess the total, direct (not mediated), and indirect (mediated through atelectasis) effects of body mass index (BMI) on preoperative Spo2, and to quantify the magnitude of mediation (proportion mediated). E-values were calculated, to represent the minimum magnitude of association that an unmeasured confounder with the same directionality of the effect should have to drive the observed point estimates or lower confidence intervals (CIs) to 1, respectively. In 236 patients with a median BMI of 40.3 kg/m2 (interquartile range [IQR], 34.6-46.0, range: 30.0-77.3), the overall prevalence of atelectasis was 32.6% (95% CI, 27.0-38.9) and by BMI category: 30 to 35 kg/m2, 12.7% (95% CI, 6.1-24.4); 35 to 40 kg/m2, 28.3% (95% CI, 17.2-42.6); 40 to 45 kg/m2, 12.3% (95% CI, 5.5-24.3); 45 to 50 kg/m2, 48.4% (95% CI, 30.6-66.6); and ≥50 units, 100% (95% CI, 86.7-100). Compared to the 30 to 35 kg/m2 group, only the categories with BMI ≥45 kg/m2 had significantly higher relative prevalence of atelectasis-45 to 50 kg/m2, aPR = 3.52 (95% CI, 1.63-7.61, E-value lower bound: 2.64) and ≥50 kg/m2, aPR = 8.0 (95% CI, 4.22-15.2, E-value lower bound: 7.91)-and higher odds of greater atelectasis percentage coverage: 45-50 kg/m2, aOR = 7.5 (95% CI, 2.7-20.9) and ≥50 kg/m2, aOR = 91.5 (95% CI, 30.0-279.3). Atelectasis percent alone explained 70.2% of the variation in preoperative Spo2. The proportion of the effect of BMI on preoperative Spo2 values <96% mediated through atelectasis was 81.5% (95% CI, 56.0-100). The prevalence and extension of atelectasis increased with higher BMI, being significantly higher at BMI ≥45 kg/m2. Preoperative atelectasis mediated the effect of BMI on Spo2 at room air in the seated position.

Exploring Synergistic GHG Emissions Mitigation Potential and Costs of Room Air Conditioners.

This study explores the potential of synergistically reducing direct (refrigerant) and indirect (electricity) greenhouse gas (GHG) emissions in the global room air conditioning (RAC) sector, based on 80% of global RAC manufactured in China. Three scenarios are evaluated: Business-as-usual (BAU) based on maintaining refrigerant and energy efficiency levels from 2021 China RAC sales shares, Kigali Amendment compliant with 10% energy efficiency improvement by 2025 (KAE), and accelerated refrigerant transition and energy efficiency improvement (ATE). Each scenario considers the costs of refrigerant and efficiency measures for export market groups based on Kigali Amendment classifications. BAU predicts around 1 Gt CO2-eq average annual global RAC emissions (2022-2060). Cumulative emission reductions in China's RAC manufacturing under KAE and ATE are 12.2 and 17.2 Gt CO2-eq A5II and A5I (except China), presenting cost-effective abatement measures, with average costs of -$51.4 and -$68.8/t CO2-eq in KAE and ATE. Cumulative average abatement costs are around $18 and $4/t CO2-eq globally. KAE and ATE scenarios would avoid surface temperature rises of 0.023 (±0.002) °C and 0.027 (±0.003) °C, respectively, versus BAU. Collaboration between China and importing countries is urged to enhance energy efficiency in RACs traded, ensuring sustainable mitigation aligned with the Kigali Amendment.

Investigations of the UVC 222 NM air cleaning system in an air-conditioned room

Far-Ultraviolet-C (far-UVC) 222 nm was introduced during the Covid-19 pandemic to disinfect the airborne pathogens, particularly SARS-CoV-2. Although far-UVC 222 nm has shown promising results in surface disinfection, its efficacy in air disinfection remains uncertain due to additional variables in air. This study investigated the efficacy of far-UVC 222 nm UVGI in air disinfection experimentally, using total plate count, and input the measured far-UVC intensity into the computational fluid dynamic model to predict infection risk using the Wells-Riley model. Experimental results indicated that after 1 h of far-UVC irradiation, an equivalent far-UVC dosage of 21.31 J/m2, airborne bacteria concentration was reduced by 44.4 %–74.1 %, while airborne fungal concentration showed a marginal reduction. In a recirculating air-conditioned room, a 20 W far-UVC fixture installation, referred to as Case 1, demonstrated the highest available dosage of 7.66 % difference compared to Case 2. The use of far-UVC in Case 1 can reduce the risk of infection for the influenza H1N1, SARS-CoV-2, and Mycobacterium tuberculosis by 54.48 %, 60.06 %, and 83.73 %, respectively. The study suggests installing far-UVC near the recirculating air-conditioner supply air jet and away from surrounding walls for optimum effectiveness. These results provide recommendations for alternatives to upper-room UVGI, offering a viable option for continuous room air and surface disinfection.

Early detection and treatment of obstructive sleep apnoea in infants with Down syndrome: a prospective, non-randomised, controlled, interventional study

Infants with Down syndrome (DS) are at high risk of obstructive sleep apnoea (OSA) which is associated with neurocognitive dysfunction and behaviour problems. The aim of our study was to evaluate the effect of early OSA treatment in infants with DS on neurocognitive development and behaviour. In this prospective, interventional, non-randomised study, 40 infants with DS underwent polysomnography (PSG) every 6 months in room air between 6 and 36 months of age (Screened Group) and were compared to a control group of 40 infants with DS receiving standard of care and a single, systematic PSG in room air at 36 months of age (Standard Care Group). When present, OSA was treated. The primary endpoint was the total score of the Griffiths Scales of Child Development, Third Edition (Griffiths III) and its subscores at 36 months. Secondary endpoints included a battery of neurocognitive and behaviour questionnaires, and PSG outcomes. On the Griffiths III, the total score was significantly higher in the Screened Group compared to the Standard Care Group (difference: 4.1; 95%CI: 1.3; 7.6; p=0.009). Results in Griffiths III subscores and secondary endpoints were in support of better neurocognitive outcomes in the Screened Group compared with the Standard Care Group. At 36 months, median (Q1; Q3) apnoea-hypopnea index was higher in the Standard Care Group (4.0 [1.5; 9.0] events/hour) compared to the Screened Group (1.0 [1.0; 3.0] events/hour, p=0.006). Moderate and severe OSA were more frequent in the Standard Care Group as compared to the Screened Group (18.9% versus 3.7% for moderate OSA and 27.0% versus 7.4% for severe OSA). Early diagnosis and treatment of OSA in infants with DS may contribute to a significantly better neurocognitive outcome and behaviour at the age of 36 months. The study was funded by the Jérôme Lejeune Foundation.

Evaluation of Inhaled Nitric Oxide Generation Systems at Altitude.

Inhaled nitric oxide (INO) is a selective pulmonary vasodilator delivered from compressed gas cylinders filled to 2,200 psig (137.8 bar) with 800 ppm of NO in a balance of nitrogen. NO is currently FDA-approved for use in term or near-term infants with hypoxemia and signs of pulmonary hypertension in the absence of cardiac disease. INO has also been shown to improve oxygenation in adults with refractory hypoxemia. Current doctrine precludes the use of NO during military aeromedical transport owing to the requirement for large compressed gas cylinders. We performed a bench evaluation of 2 delivery systems that create NO from room air without the need for pressurized cylinders. We evaluated 2 portable nitric oxide INO generation systems (LungFit PH, Beyond Air Inc, Garden City, NJ and a prototype NO generator, Odic Inc, Littleton, MA) at ground level, 8,000, and 14,000 feet (2,437 and 4,267 meter) simulated altitude in an altitude chamber. The output from each device was injected into the inspiratory limb of the ventilator circuit that was attached to a test lung. A 731 ventilator (Zoll Medical, Chelmsford, MA) and T1 (Hamilton Medical, Reno, NV) were used employing 24 combinations of ventilator settings each repeated in duplicate. An INOmax DS IR was used to measure delivered INO and NO2 via a sampling line attached in the ventilator circuit inspiratory limb. A fast response oxygen analyzer (O2CAP, Oxigraf Inc, Sunnyvale, CA) was used to measure inspired FiO2. Target INO concentration was 20 ppm. Across all ventilator settings, the LungFit device delivered INO was 19.8 ± 1.6 ppm, 16.1 ± 1.9 ppm, and 11.6 ± 1.7 ppm at ground level, 8,000 ft (2,437 meter), and 14,000 ft (4,267 meter), respectively. The Odic device delivered INO dose was 20.6 ± 1.4 ppm, 21.3 ± 5.5 ppm, and 20.4 ± 9.1 ppm at ground level, 8,000 ft (2,437 meter), and 14,000 ft (4,267 meter), respectively. Both devices delivered a reliable INO dose at ground level. Altitude significantly affected INO delivery accuracy at 14,000 ft (4,267 meter) (P < 0.01) with both devices and at 8,000 ft (2,437 meter) (P < 0.01) with LungFit. Differences in INO dosage were not statistically significant with the Odic device at 8,000 ft (2,437 meter)(P > 0.05) although there were large variations with selected ventilator settings. With careful monitoring, devices creating INO from room air without cylinders could be used during aeromedical transport without the need for pressurized cylinders.

Quantitative and qualitative assessment of airborne microorganisms during gross anatomical class and the bacterial and fungal load on formalin-embalmed corpses

Mold growth on body donations remains an underreported yet serious issue in anatomical teaching. Bacterial and fungal growth pose health risks to lecturers and students, alongside with ethical and aesthetic concerns. However, limited information exists on the presence of bacteria and fungi on body donations and their underlying causes. To investigate the potential impact of airborne germs on body donation contamination, we conducted indoor air measurements before, during, and after our anatomical dissection course, with outdoor measurements serving as a control. Tissue samples from the dissected body donations were collected to assess the germ load, with qualitative and quantitative microbiological analyses. Air samples from the dissection hall contained no fungi, but various fungal species were identified in the adjacent stairways and outdoors which implies that fungal occurrence in the dissection hall air was independent of lecturers’ and students’ presence. Moreover, our results indicate that adequate ventilation filters can effectively reduce indoor fungal germs during courses, while the bacterial load in room air appears to increase, likely due to the presence of lecturers and students. Additionally, the tissue samples revealed no bacterial or fungal germs which implies that our ethanol-formalin-based embalming solution demonstrates an effective long-term antimicrobial preservation of corpses.

Evaluation of oxygen administration in cesarean section under spinal anesthesia via lung ultrasound and the oxygen reserve index

BackgroundRespiratory functions may be impaired in cesarean section (C/S) delivery performed under spinal anesthesia (SA) and oxygen supplementation may be required. Therefore, we conducted a randomized controlled study aimed to evaluate the effects of different oxygen administrations in pregnant women on the lungs during C/S under SA using ultrasound and oxygen reserve index (ORI).MethodsWe conducted a randomized, controlled, single-center study from May 1, 2021, to March 31, 2022. A total of 90 patients scheduled for C/S under SA were randomly divided into 3 groups. Following the SA, patients in group 0 were treated with room air, in Group 3 were administered 3 L/min O₂ with a nasal cannula (NC), in Group 6 were administered 6 L/min O₂ with a simple face mask. In addition to routine monitoring, ORI values were measured. Lung aeration was evaluated through the modified lung ultrasound score (LUS) before the procedure (T0), at minute 0 (T1), 20 (T2), and hour 6 (T3) after the procedure, and ∆LUS values were recorded.ResultsAfter SA, the ORI values of Group 3 were higher than Group 0 at all times (p < 0.05), while the intraoperative 1st minute and the 10th, 25th and 40th minutes after delivery (p = 0.001, p = 0.027, p = 0.001, p = 0.019) was higher than Group 6. When the LUS values of each group were compared with the T0 values a decrease was observed in Group 3 and Group 6 (p < 0.001, p = 0.016). While ∆LUS values were always higher in Group 3 than in Group 0, they were higher only in T1 and T2 in Group 6.ConclusionWe determined that it would be appropriate to prefer 3 L/min supplemental oxygen therapy with NC in C/S to be performed under SA.

Role of sex as a biological variable in neonatal alveolar macrophages

The lung macrophages play a crucial role in health and disease. Sexual dimorphism significantly impacts the phenotype and function of tissue-resident macrophages. The primary mechanisms responsible for sexually dimorphic outcomes in bronchopulmonary dysplasia (BPD) remain unidentified. We tested the hypothesis that biological sex plays a crucial role in the transcriptional state of alveolar macrophages, using neonatal murine hyperoxia-induced lung injury as a relevant model for human BPD. The effects of neonatal hyperoxia exposure (95 % FiO2, PND1-5: saccular stage) on the lung myeloid cells acutely after injury and during normoxic recovery were measured. Alveolar macrophages (AM) from room air- and hyperoxia exposed from male and female neonatal murine lungs were subjected to bulk-RNA Sequencing. AMs are significantly depleted in the hyperoxia-exposed lung acutely after injury, with subsequent recovery in both sexes. The transcriptome of the alveolar macrophages is impacted by neonatal hyperoxia exposure and by sex as a biological variable. Pathways related to DNA damage and interferon-signaling were positively enriched in female AMs. Metabolic pathways related to glucose and carbohydrate metabolism were positively enriched in the male AMs, while oxidative phosphorylation was negatively enriched. These pathways were shared with monocytes and airway macrophages from intubated male and female human premature neonates.

Intraocular Pressure and Safety of Vitrectomy with Vitreous Gas Replacement using Low-concentration Nitrous Oxide Gas Anesthesia.

This study aims to evaluate the efficacy and safety of vitrectomy with vitreous gas replacement using low-concentration nitrous oxide (N2O) gas anesthesia, focusing on intraocular pressure (IOP) changes, pain, anxiety, and safety outcomes. This retrospective study analyzed 133 patients undergoing fluid-air exchange without use of such as SF6 or C3F8, at Saneikai Tsukazaki Hospital, Japan, from April 2019 to March 2022. Participants were divided into two groups: those receiving low-concentration nitrous oxide gas anesthesia (N2O group) and those receiving local anesthesia with room air inhalation (Air group). IOP, pain, anxiety levels, and intraoperative complications were assessed. No significant differences were found in IOP changes postoperatively between the N2O and Air groups. The N2O group reported significantly lower pain scores and had lower intraoperative systolic blood pressure and heart rate changes compared with the Air group. No significant intraoperative or postoperative complications were observed in either group. Vitrectomy with fluid-air exchange using low-concentration nitrous oxide gas anesthesia is safe, does not increase IOP, and may offer benefits in reducing intraoperative pain and stabilizing vital signs compared with traditional local anesthesia methods. This approach could be considered a viable option for vitreous surgery requiring fluid-air exchange.

Natural Products in the Treatment of Retinopathy of Prematurity: Exploring Therapeutic Potentials.

Retinopathy of prematurity (ROP) is a vascular disorder affecting the retinas of preterm infants. This condition arises when preterm infants in incubators are exposed to high oxygen levels, leading to oxidative stress, inflammatory responses, and a downregulation of vascular endothelial growth factors, which causes the loss of retinal microvascular capillaries. Upon returning to room air, the upregulation of vascular growth factors results in abnormal vascular growth of retinal endothelial cells. Without appropriate intervention, ROP can progress to blindness. The prevalence of ROP has risen, making it a significant cause of childhood blindness. Current treatments, such as laser therapy and various pharmacologic approaches, are limited by their potential for severe adverse effects. Therefore, a deeper understanding of ROP's pathophysiology and the development of innovative treatments are imperative. Natural products from plants, fungi, bacteria, and marine organisms have shown promise in treating various diseases and have gained attention in ROP research due to their minimal side effects and wide-ranging beneficial properties. This review discusses the roles and mechanisms of natural products that hold potential as therapeutic agents in ROP management.

Radioactivity concentration of 14C in the air of 14C urea breath test rooms and the resulting internal dose to medical staff

ObjectiveTo monitor the radioactivity concentration of 14C in the air of rooms used to perform 14C urea breath tests, and evaluate the contamination status of 14C released during such tests, and assess the occupational health risk to medical staff working in such areas. Methods14CO2 in air was absorbed from the air and turned into calcium carbonate through a chemical reaction. Then, calcium carbonate was prepared into a suspension in a low-potassium glass vial. The sample was analyzed using a low-background liquid scintillation counter. ResultsThe radioactivity concentrations of 14C in air of the breath-test rooms in hospitals and physical examination institutions range from 1.35 to 18.41 Bq/m3. The annual committed dose for medical staff was estimated to be between 2.01 × 10−2 and 2.74 × 10−1 μSv. ConclusionsOur results reveal a significant increase of 14C radioactivity concentration in the air of breath-test rooms, but the resulting committed dose is much lower than the limits prescribed by the International Commission on Radiological Protection (ICRP). However, the potential risk of long-term exposure to low-dose radiation should be paid more attention.

Clinical outcomes and phenotypes of respiratory failure in older subjects admitted to an acute care geriatric hospital ward.

Respiratory failure (RF) is frequent in hospitalized older patients, but was never systematically investigated in large populations of older hospitalized patients. We conducted a retrospective administrative study based on hospitalizations of a Geriatrics Unit regarding 2014, 2015, and 2016. Patients underwent daily screening for hypoxia. Hospital discharge records were coded through a standardized methodology. RF, defined as documented hypoxia on room air, was always coded, whenever present. We investigated how RF affected clinical outcomes, whether RF grouped into specific comorbidity phenotypes, and how phenotypes associated with the outcomes. RF was coded in 48.6% of the 1,810 hospitalizations. RF patients were older and more frequently had congestive heart failure (CHF: 49 vs 23%), chronic obstructive pulmonary disease (COPD: 27 vs 6%), pneumonia (14 vs 4%), sepsis (12 vs 7%), and pleural effusion (6 vs 3%), than non-RF patients. RF predicted longer length of stay (a-Beta 2.05, 95% CI 1.4-2.69; p < 0.001) and higher in-hospital death/intensive care units (ICU) need (aRR 7.12, 5-10.15; p < 0.001) after adjustment for confounders (linear and Poisson regression with robust error variance). Among RF patients, cerebrovascular disease, cancer, electrolyte disturbances, sepsis, and non-invasive ventilation predicted increased, while CHF and COPD predicted decreased in-hospital death/ICU need. The ONCO (cancer) and Mixed (cerebrovascular disease, dementia, pneumonia, sepsis, electrolyte disturbances, bedsores) phenotypes displayed higher in-hospital death/ICU need than CARDIO (CHF) and COPD phenotypes. In this study, RF predicted increased hospital death/ICU need and longer hospital stay, but also reflected diverse underlying conditions and clinical phenotypes that accounted for different clinical courses.

Mitochondrial function in lungs of rats with different susceptibilities to hyperoxia-induced acute lung injury.

Adult rats exposed to hyperoxia (>95% O2) die from respiratory failure in 60-72 h. However, rats preconditioned with >95% O2 for 48 h followed by 24 h in room air acquire tolerance of hyperoxia (H-T), whereas rats preconditioned with 60% O2 for 7 days become more susceptible (H-S). Our objective was to evaluate lung tissue mitochondrial bioenergetics in H-T and H-S rats. Bioenergetics was assessed in mitochondria isolated from lung tissue of H-T, H-S, and control rats. Expressions of complexes involved in oxidative phosphorylation (OxPhos) were measured in lung tissue homogenate. Pulmonary endothelial filtration coefficient (Kf) and tissue mitochondrial membrane potential (Δψm) were evaluated in isolated perfused lungs (IPLs). Results show that ADP-induced state 3 OxPhos capacity (Vmax) decreased in H-S mitochondria but increased in H-T. Δψm repolarization time following ADP-stimulated depolarization increased in H-S mitochondria. Complex I expression decreased in H-T (38%) and H-S (43%) lung homogenate, whereas complex V expression increased (70%) in H-T lung homogenate. Δψm is unchanged in H-S and H-T lungs, but complex II has a larger contribution to Δψm in H-S than H-T lungs. Kf increased in H-S, but not in H-T lungs. For H-T, increased complex V expression and Vmax counter the effect of the decrease in complex I expression on Δψm. A larger complex II contribution to Δψm along with decreased Vmax and increased Kf could make H-S rats more hyperoxia susceptible. Results are clinically relevant since ventilation with ≥60% O2 is often required for extended periods in patients with acute respiratory distress syndrome (ARDS).NEW & NOTEWORTHY We assessed lung tissue mitochondrial bioenergetics in rats with tolerance (H-T) or susceptibility (H-S) to hyperoxia-induced ARDS. Results from studies in isolated mitochondria, tissue homogenate, and isolated perfused lungs show that mitochondrial bioenergetics are differentially altered in H-T and H-S lungs suggesting a potential role for mitochondrial bioenergetics in hyperoxia-induced ARDS. Results are clinically relevant since hyperoxia exposure is a primary therapy for patients with ARDS, and differential sensitivity to hyperoxia surely occurs in humans.

Similar endothelium-dependent vascular responses to intermittent hypoxia in young and older adults.

Aging is associated with vascular endothelial dysfunction observed through a progressive loss of flow-mediated dilation caused partly by a decreased nitric oxide bioavailability. Intermittent hypoxia, consisting of alternating short bouts of breathing hypoxic and normoxic air, was reported to either maintain or improve vascular function in young adults. The aim of this study was to determine the impact of age on the vascular response to intermittent hypoxia. Twelve young adults and 11 older adults visited the laboratory on two occasions. Plasma nitrate concentrations and brachial artery flow-mediated dilation were assessed before and after exposure to either intermittent hypoxia or a sham protocol. Intermittent hypoxia consisted of eight 4-min hypoxic cycles at a targeted oxygen saturation of 80% interspersed with breathing room air to resaturation, and the sham protocol consisted of eight 4-min normoxic cycles interspersed with breathing room air. Vascular responses were assessed during intermittent hypoxia and the sham protocol. Intermittent hypoxia elicited a brachial artery vasodilation but did not change brachial artery shear rate in both young and older adults. Plasma nitrate concentrations were not significantly affected by intermittent hypoxia compared with the sham protocol in both groups. Brachial artery flow-mediated dilation was not acutely affected by intermittent hypoxia or the sham protocol in either young or older adults. In conclusion, the brachial artery vasodilatory response to intermittent hypoxia was not influenced by age. Intermittent hypoxia increased brachial artery diameter but did not acutely affect endothelium-dependent vasodilation in young or older adults.NEW & NOTEWORTHY The objective of this study was to determine the impact of age on the vascular response to intermittent hypoxia. Eight 4-min bouts of hypoxia at a targeted oxygen saturation of 80% induced a brachial artery vasodilation in both young and older adults, indicating that age does not influence the vasodilatory response to intermittent hypoxia. Intermittent hypoxia did not acutely affect brachial artery flow-mediated dilation in young or older adults.

Feed-forward compensation for emulator-type testing facilities

Defining the required trackability level of the target condition for the testing facility reconditioning unit represents an unresolved challenge in improving the reproducibility of load-based tests and corresponding performance rating standards development. To enhance the reproducibility of such testing methodology, this paper presents and discusses a new feed-forward compensation technique based on the development of a transfer function model for the delay and offset characteristics of the psychrometric room's air temperature and humidity modulations with reference to the target signal from the room emulator. It is demonstrated that the proposed methodology enables offset and delay reduction in the trackability of the return air condition within 60 s at different testing conditions, enhances the reproducibility of the test results to limit performance deviations to within 2 %, and achieves closely matched controlled parameter modulations during load-based tests.

Exosomal miR-106a-5p derived from intermittently hypoxic non-small-cell lung cancer increases tumor malignancy.

Intermittent hypoxia (IH) is a hallmark of obstructive sleep apnea (OSA), which is related to tumorigenesis and progression. We explored the possible mechanisms by which OSA may promote the development of non-small cell lung cancer (NSCLC). In this study, NSCLC cells with and without miR-106a-5p inhibition were exposed to IH or room air (RA), and subsequently, exosomes were extracted and identified. Macrophages were incubated with these exosomes to detect the expression of the STAT3 signaling pathway and M2-type macrophage markers, as well as the effect of the macrophages on the malignancy of NSCLC cells. A nude mouse tumorigenesis model was constructed to detect the effects of exosomal miR-106a-5p on M2 macrophage polarization and NSCLC cell malignancy. Our results showed that IH exosomes promoted the polarization of M2 macrophages, thereby promoting the proliferation, invasion, and metastasis of NSCLC cells. Further, Based on microarray analysis of RA and IH exosomes, we discovered that miR-106a-5p, transferred to the macrophages through exosomes, participated in this mechanism by promoting M2 macrophage polarization via down-regulating PTEN and activating the STAT3 signaling pathway invitro and invivo. For patients with NSCLC and OSA, exosomal miR-106a-5p levels showed a positive relation to AHI. Exosomal miR-106a-5p represents a potential therapeutic target among patients with concomitant cancer and NSCLC.

Performance Analysis of Lake Water Cooling Coupled with a Waste Heat Recovery System in the Data Center

Data centers (DCs) require continuous cooling throughout the year and produce a large amount of low-grade waste heat. Free cooling and waste heat recovery techniques are promising approaches to reduce DC energy consumption. Although previous studies have explored diverse waste heat utilization strategies, there is a significant gap in combining waste heat recovery with lake water cooling in DCs. Therefore, this study proposed a system integrating lake water cooling with waste heat recovery for DCs. To evaluate the energy-saving performance of the suggested system, the influence of waste heat recovery locations and volumes has been investigated. An analysis of the improvement in system parameters is also conducted. The study’s findings highlight that targeted recovery of waste heat from sources like chilled water or air in server rooms can significantly reduce the cooling energy demand of the system. The results show that recovering heat from the return air of IT equipment can yield a remarkable power usage effectiveness (PUE) and coefficient of performance (COP) of 1.19 and 10.17, and the energy consumption of the cooling system is reduced to 10.06%. Moreover, the outcomes reveal the potential for substantial energy savings of up to 26.05% within the proposed system by setting the chilled water and air supply temperatures to 16 and 20 °C, respectively.

Development of An Automatic Detection System for Environmental Feasibility of Artificial Microgreen Planting Based on IoT Sensors

One of the issues that needs to be acknowledged by all parties is the decreasing agricultural land due to its conversion into residential areas, while the human population continues to grow in proportion to food demand. Urban farming emerges as a solution to address the constraints of agricultural land by utilizing available space. Moreover, urban farming could be the support for food security, especially at the household level. The utilization of IoT technology could be applied to support this urban farming initiative. We have designed a prototype of an artificial ricefield for microgreen cultivation that is integrated with IoT to monitor the planting process and provide environmental feasibility recommendations. Environmental feasibility recommendations are measured by three indicators: room temperature, air humidity, and soil moisture. The devices used are the DHT11 sensor for detecting temperature and air humidity, and the NodeMCU ESP32 DevKit V.1 microcontroller for data processing, enabling the DHT11 sensor detections to be displayed on a website. The test results show that the Mean Squared Error (MSE) for each indicator is as follows: temperature 2,9 %, air humidity 3,9 %, and soil moisture 5,4%. Because each indicator of the MSE value obtained is low, this prototype is suitable for development.