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Residential altitude has been proposed as a potential determinant of auditory function, but evidence from long-term high-altitude residents remains limited. This cross-sectional study included 187 plateau residents aged ≤50 years undergoing health examination at the Affiliated Hospital of Qinghai University. Participants were classified into lower- (2,200-2,499 m, n = 79), middle- (2,500-3,499 m, n = 51), and higher-altitude (≥3,500 m, n = 57) strata according to long-term residential altitude. Mean bilateral thresholds at 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, and 8 kHz, together with LM-PTA and HF-PTA, were compared across groups. Complementary Kruskal-Wallis analyses, minimally and fully adjusted models, continuous-altitude analyses, exploratory quadratic-term analysis for PTA at 8 kHz, and repeated-measures ANCOVA were performed. Unadjusted analyses showed more pronounced between-group differences at higher frequencies, with statistically significant differences for HF-PTA, PTA at 4 kHz, PTA at 8 kHz, and LM-PTA. Continuous-altitude models did not support a stable linear trend. In the fully adjusted model, altitude-stratified effects were no longer statistically significant for HF-PTA, PTA at 4 kHz, or LM-PTA, but remained statistically significant for PTA at 8 kHz (p = 0.032). Bonferroni-corrected comparisons showed that only the difference in PTA at 8 kHz between the lower- and middle-altitude strata remained statistically significant. The fully adjusted repeated-measures ANCOVA did not show a statistically significant Frequency × altitude group interaction. Hearing-threshold differences across residential altitude strata were more apparent at higher frequencies in unadjusted analyses; after adjustment for age, sex, and other clinical factors, the most robust independent altitude-stratified association remained at 8 kHz.

Chronic exposure to hypoxia occurs in lowland populations, including soldiers, adventurers, tourists, and porters, during their ascent to high altitude. Hypobaric hypoxia induces oxidative stress and impairs the metabolism of micro minerals, including selenium, zinc, iron, and copper. The role of metalloproteins and their associated microminerals in preventing oxidative stress at different altitudes is incompletely understood. In this study, plasma samples were collected from lowlanders at sea level (SL), moderate altitude (A1-1585&#xa0;m, A2-2290&#xa0;m), and high altitude (A3-3500&#xa0;m). Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to quantify selenium (Se), zinc (Zn), copper (Cu), and iron (Fe) levels. Antioxidant metalloproteins, including Copper-Zinc Superoxide dismutase (Cu-Zn SOD), Glutathione Peroxidase (GPx), Metallothionein (MT), Selenoprotein 1 (SEPP1), were quantified by enzyme-linked immunosorbent assay. Lipid peroxidation was assessed through malondialdehyde (MDA) and hydroperoxides through ferrous oxidation xylenol orange; FOX1 assay. We found that Se, Zn, Cu, and Fe levels were higher (p&#x2009;<&#x2009;0.01) at A2 compared to SL and lower (p&#x2009;<&#x2009;0.01) at A3 compared to A2. MT levels were higher (p&#x2009;<&#x2009;0.01) at A1 and A3 compared to SL. SEPP1 levels were higher (p&#x2009;<&#x2009;0.001) at A3 compared to SL, A1, and A2. Cu-Zn SOD levels were higher at A3 (p&#x2009;=&#x2009;0.006). GPx levels remained consistent across all altitudes. MDA levels were significantly elevated (p&#x2009;=&#x2009;0.013) at A3 compared to SL, while the FOX assay showed increased hydroperoxide levels (p&#x2009;<&#x2009;0.001) at A2 and A3 as compared to SL. Our findings demonstrate that hypoxia leads to variations in micromineral levels at different altitudes, accompanied by elevated oxidative stress and dysregulated antioxidant metalloproteins potentially reflecting adaptive responses to oxidative stress at high altitude.

High altitude may adversely affect patients with pulmonary vascular disease (PVD), but acute cardiopulmonary effects remain unclear. How does two-day high-altitude exposure affect pulmonary hemodynamics and oxygen delivery in patients with PVD defined as pulmonary arterial or chronic thromboembolic pulmonary hypertension? In this randomized, controlled crossover trial, stable, low-risk patients with PVD without resting hypoxemia at 470 m were transported by cable car to 2500 m, where they stayed for two days. Systolic pulmonary arterial pressure (sPAP), total pulmonary resistance (TPR), right ventricular (RV) -arterial coupling, pulmonary arterial elastance (EA) and compliance (PAC) were assessed by echocardiography, while oxygen content was measured in arterial blood gases. Twenty-seven patients with PVD (44% women, 61&#xb1;14 years) were included. Altitude exposure was associated with an increase in sPAP of 18 mmHg (40%, 95%CI: 9 to 28 mmHg, p<0.001) and TPR of 2.8 WU (32%, 0.7 to 4.9 WU, p=0.007). RV-arterial coupling, assessed by TAPSE/sPAP ratio, decreased from 0.55&#xb1;0.04 to 0.38&#xb1;0.04 mm/mmHg (-31%, -0.27 to -0.07 mm/mmHg, p<0.001). EA increased by 0.2 mmHg/mL (33%, 0.07 to 0.33 mmHg/mL, p<0.001) and PAC decreased by 1.6 mL/mmHg (38%, -2.7 to -0.6 mL/mmHg, p=0.002). Although oxygen content was lower at high altitude, oxygen delivery was similar at both altitudes. Two-day exposure to 2500 m in stable, low-risk patients with PVD increases RV resistive and pulsatile afterload and decreases TAPSE/sPAP, indicating reduced RV-arterial coupling. Despite attenuated cardiac adaptation, overall function appears sufficient to maintain oxygen delivery and partially compensate for hypoxemia. Clinicaltrials.gov (NCT05107700).

C. nutans, a highly advantageous forage grass on the Western Sichuan Plateau, remains poorly studied in terms of its chromosomal structural diversity in this region. The genomic and chromosomal organization of C. nutans was investigated using GISH and ND-FISH with four oligonucleotide probes. The results showed that repetitive sequence distribution exhibited genome-specific patterns: the H genome demonstrated high structural stability with low polymorphism, while the St genome showed moderate variation, and the Y genome displayed the highest polymorphism, with chromosomes 1Y, 2Y, and 7Y identified as variation hotspots. Signal density and polymorphism varied with altitude; the materials from middle and low altitudes exhibited relatively higher genetic polymorphism. Notably, (AAG)10 and (GAA)7 probes revealed altitudinal trends, with signal abundance peaking at mid-elevations before declining at higher altitudes. 5S rDNA and pAs1 distributions further highlighted conserved loci alongside altitude-dependent polymorphisms. Karyotypic analysis based on probe combinations confirmed uneven intragenomic variation, with 3H, 1St/3St, and 1Y/7Y showing the highest diversity. These findings underscore the differential genome plasticity in C. nutans, with the Y genome being the most dynamic, possibly as an adaptive response to environmental gradients. The study provides insights into the evolutionary mechanisms and altitude-driven genomic diversification in polyploid grasses.

Chronic mild hypoxia at moderate altitude (2260&#x202f;m) has been linked to improved systemic metabolism, but its liver-specific associations under high-energy diets remain incompletely defined. In this study, age-matched male C57BL/6&#x202f;J mice were maintained for 15&#x202f;weeks at simulated low altitude (50&#x202f;m) or moderate altitude (2260&#x202f;m) while fed a normal diet (ND), high-fat diet (HFD), or HFD with 30% fructose (HFD&#x202f;+&#x202f;HFr). Hepatic outcomes were assessed using ultrasonography, histology, electron microscopy, serum biochemistry, targeted energy metabolomics, lipidomics, and immunoblotting. Compared with the corresponding low-altitude high-energy diet groups, mice at 2260&#x202f;m showed lower diet-associated weight gain, hepatic steatosis, and ALT/AST elevations. Structural analyses showed reduced lipid-droplet accumulation and qualitatively improved mitochondrial ultrastructural appearance. Metabolomics showed coordinated decreases in steady-state intermediates across glycolysis, the pentose phosphate pathway, and the tricarboxylic acid cycle relative to the 50&#x202f;m HFD group, together with enzyme changes consistent with reduced lipogenic capacity and altered fatty-acid uptake/oxidation. Lipidomic profiling further showed lower accumulation of neutral lipids, including triglycerides and diacylglycerols, as well as sphingolipids, while phospholipid class-level composition appeared less disturbed. Overall, moderate-altitude exposure was associated with attenuation of high-energy-diet-related hepatic metabolic dysfunction and with coordinated metabolic remodeling. These findings identify chronic mild hypoxia as an important contextual factor associated with hepatic metabolic responses, while direct causal mechanisms require further validation.

A major health issue in individuals living at high-altitude regions is an increase in the number of red blood cells (RBCs). This condition generates a series of physiological alterations including the nervous system, where damage can occur due to increased blood viscosity. This increased viscosity, in turn, could compromise oxygen uptake, potentially linked to a degree of cognitive impairment. To determine the association between exposure to chronic hypoxia and sleep quality with the degree of cognitive impairment in a young adult population residing at different altitude levels. A cross-sectional study was conducted with 200 apparently healthy subjects (aged 21-26 years) permanently residing in four Peruvian cities: Lima (154 m), Arequipa (2335 m), Puno (3820 m), and La Rinconada (5100 m) (n = 50 per location). Physiological profiles (SpO2, blood pressure, heart rate, hemoglobin, and hematocrit) were measured. Cognitive impairment and sleep quality were evaluated using the Montreal Cognitive Assessment (MoCA) and the Pittsburgh Sleep Quality Index (PSQI). Sex-stratified hierarchical multiple linear regression models with bootstrapping were utilized for independent correlation analysis. Hemoglobin levels gradually increased with altitude, peaking at 19.47 &#xb1; 3.01 g/dL in La Rinconada, while SpO2 decreased to 81.64%. Moderate-to-severe cognitive impairment was exclusively restricted to the extreme altitude population of La Rinconada, where only 10% of subjects remained unaffected. In the sex-stratified multivariate regression, residency in La Rinconada initially served as a robust negative predictor of MoCA scores among women (&#x3b2; = -5.52, p < 0.001); however, this geographical effect lost statistical significance after adjusting for biological variables in Model 2 (&#x3b2; = -4.72, p = 0.178). In the fully adjusted models, neither individual hemoglobin levels nor SpO2 fluctuations displayed an independent linear association with cognitive performance in either sex (p > 0.05). Sleep quality was poor across cohorts but showed no significant association with cognitive impairment (p = 0.174). Chronic exposure to severe hypoxia (>5000 m) is associated with a greater presence of cognitive impairment, which is largely accounted for by individual physiological adaptations rather than isolated, linear effects of independent hematological or subjective sleep parameters.

This study evaluated the adaptability of Holstein cattle to high-altitude environments following their relocation from low-altitude regions (<500 m) to the Qinghai-Tibet Plateau (>3,500 m) and identified risk factors associated with physiological maladaptation. A cohort of 1,000 healthy Holstein heifers was relocated and monitored over a 5-mo period, with observations focusing on mortality rates, clinical symptoms, hematological parameters, and pulmonary arterial pressure. Postmortem examinations and 16S rRNA sequencing of gut microbiota were conducted. The observed mortality rate was 30.5%. The predominant clinical manifestations included anorexia, edema, pulmonary hypertension, and hematological abnormalities. Postmortem analyses confirmed that right-sided heart failure secondary to hypoxic pulmonary hypertension was the principal cause of mortality. Holstein heifers that survived exhibited a higher relative abundance of bacteria associated with energy metabolism, such as Tenericutes, TM7, Clostridium, Treponema, and Paludibacter, in comparison to those that did not survive. Immediate relocation to elevations exceeding 3,500 m presents significant risks. To mitigate these risks, it is recommended to restrict altitude transitions to 1,500 m or less. An alternative approach involves implementing a gradual acclimatization strategy, which includes adaptive rearing at elevations of 2,500 m or lower for a minimum period of 5 mo, alongside specific dietary modifications and probiotic supplementation. These findings provide both practical and theoretical foundations for the effective health management of Holstein heifers in high-altitude environments.

&#xa0;Highaltitude hypoxia impairs frontal executive functions. This study examines whether serum creatinine mediates the relationship between altitude acclimatization (AAI) SpO&#x2082;/HCT ratio and frontal neural oscillations. &#xa0;In 190 adults at 3,650&#x202f;m (Lhasa), we measured SpO&#x2082;, hematocrit, serum creatinine, and restingstate frontal EEG. Power spectral density was calculated across multiple frequency bands (1-80&#x202f;Hz) and Zstandardized. Mediation analysis with bootstrap tested the indirect effect of AAI on each band via creatinine. &#xa0;AAI significantly negatively predicted creatinine (p < 0.001). Creatinine significantly negatively predicted frontal ZPSD in theta (4-7&#x202f;Hz), alpha (8-13&#x202f;Hz), and beta (14-30&#x202f;Hz) bands (all&#xa0;p < 0.01), but not in other bands. The indirect effect via creatinine was significant for theta (p = 0.011, partial mediation), alpha (p = 0.031, full mediation), and beta (p = 0.020, full mediation). &#xa0;The kidneybrain axis mediates hypoxic neurocognitive adaptation with frequencyspecific patterns. Creatinine dynamics reflect acclimatization efficacy, suggesting a target for preserving frontal executive function at high altitude.

The associations between ambient fine particulate matter (PM2.5) and its components (sulfate, ammonium, nitrate, organic matter, and black carbon) and the risk of preeclampsia remain unclear, particularly in high-altitude regions where evidence is limited. This study aimed to provide novel insights into this issue. Lanzhou, China, was selected as a representative high-altitude city, and data from 169,484 women who delivered between 2016 and 2021 were included. Logistic regression models were used to evaluate the associations between individual exposure to PM2.5 and its components and the risk of preeclampsia. The joint associations and the contribution weights of each component were further assessed using quantile g-computation. Additionally, distributed lag nonlinear models were applied to identify potential lagged associations. The results indicated that individual exposures to PM2.5 and its components during the entire exposure period, the preconception period, and the first trimester were significantly associated with an increased risk of preeclampsia (p < 0.05). Mixed exposures to PM2.5 components during the entire exposure period and the preconception period were also significantly associated with an increased risk of preeclampsia (p < 0.05), with black carbon (0.43) and ammonium (0.48) showing the highest positive weights, respectively. The strongest associations between high-level pollutant exposure and preeclampsia risk were observed during the preconception period or the first trimester. These findings suggest that public health interventions should target key PM2.5 components and critical exposure windows to mitigate the risk of preeclampsia in high-altitude regions.

Xie, Weiwei, Xianli Wu, Yiding Li, Qing Xiang, Na Wu, Haolun Sun, Bianba Duojie, Hongda Zhao, Jun Liang, and Ye Fan. Erythrocytapheresis Improves Health-Related Quality of Life in High-Altitude Migrans with Chronic Mountain Sickness: A Single-Arm Before-After Trial at 4,000-4,500 m. High Alt Med Biol. 00:00-00, 2026.Chronic mountain sickness (CMS) arises from maladaptive responses to prolonged residence at altitudes exceeding 2,500 m. Despite the known efficacy of erythrocytapheresis on CMS, the impact of this intervention on health-related quality of life for individuals diagnosed with CMS remains poorly understood. We conducted a single-arm before-after trial using erythrocytapheresis on a total of 22 male migrants with CMS who had resided at high altitudes (4,000-4,500 m) for 6.5 (3.8, 9.3) years. Participants underwent between 1 and 4 erythrocytapheresis sessions, with 1-2 days between each one. The participants exhibited significant improvements following the intervention: health-related quality of life score increased from 85.0 (80.0, 85.3) to 90.0 (90.0, 94.3) (p < 0.001, d = 0.57); CMS score decreased from 7.0 (6.0, 8.0) to 3.0 (2.8, 4.0) (p < 0.0001, d = 0.62); the distance in the 6-Minute Walk Test improved from 612.5 (598.8, 623.0) meters to 654.0 (636.3, 676.3) meters (p < 0.0001, d = 0.62); and SpO2 levels rose from 87.5 (85.8, 90.0) to 90.0 (87.0, 92.5) (p = 0.012, d = 0.38). Erythrocytapheresis proves to be an effective intervention for enhancing health-related quality of life and reducing the severity of CMS in migrant populations.

The rapid expansion of urban air mobility operations demands adaptive airspace management approaches that transcend traditional static sectorization. This paper proposes an integrated framework for dynamic low-altitude airspace partitioning and management strategy optimization by fusing graph neural networks with spatial cognitive science. Urban low-altitude airspace is modeled as an attributed weighted directed graph encoding spatial adjacency, traffic flow coupling, and environmental constraints. A spatial cognitive constraint system is developed, quantifying boundary discriminability, shape complexity, and hierarchical cognitive load as differentiable optimization terms. A cognition-enhanced graph attention network architecture with spatiotemporal feature aggregation is designed to generate end-to-end partition assignments, with an explicit cognitive attention modulation mechanism that steers message-passing toward perceptually coherent neighborhoods. A reinforcement learning module, formalized as a Markov decision process with clearly defined state, action, and reward spaces, fine-tunes the partition and management strategy outputs through proximal policy optimization. The joint training scheme co-optimizes sector boundaries with capacity allocation, priority sequencing, and conflict alert policies through multi-task learning with curriculum scheduling. Experimental results on both synthetic simulation data and real-world ADS-B trajectory data from the OpenSky Network demonstrate that the proposed method achieves an airspace utilization rate of 81.2&#x2009;&#xb1;&#x2009;1.4% and reduces the flight conflict rate to 3.1&#x2009;&#xb1;&#x2009;0.5 per 100 flight-hours, representing a 46.6% improvement over vanilla graph attention baselines and outperforming advanced spatiotemporal GNN baselines including STGCN and DCRNN. Statistical significance is confirmed via Wilcoxon signed-rank tests (p&#x2009;<&#x2009;0.01). A small-scale human-in-the-loop study with eight certified air traffic management researchers points to a roughly 37% reduction in operator decision response time, a signal we read as preliminary rather than conclusive given the modest sample. Scalability tests indicate that model inference alone stays feasible up to 10,000-node airspace graphs within the reconfiguration window, though we are careful to note that the complete operational pipeline has not yet been integrated end-to-end.

Successful cooperation requires the efficient integration of self and other-related information. Whether hyperbaric oxygen intervention improves cooperative performance under high-altitude hypoxic conditions, and whether such effects depend on interpersonal neural coordination, remains unclear. In this randomized crossover study, 62 dyads completed a cooperative task under both hyperbaric oxygen intervention and high-altitude hypoxic conditions while undergoing fNIRS hyperscanning. We examined whether hyperbaric oxygen intervention enhanced cooperative performance and whether this effect was associated with interpersonal trust and inter-brain synchrony (IBS). High-trust dyads exhibited greater hyperbaric-oxygen-related cooperation gains. Increases in medial prefrontal cortex (mPFC) IBS predicted improvements in cooperation success rate and cooperation efficiency, and both associations were moderated by interpersonal trust: positive associations were observed only in high-trust dyads. Pseudo-dyad analyses further indicated that this effect reflected real interpersonal interaction rather than shared task structure. These findings suggest that the cooperative benefits of hyperbaric oxygen intervention are not uniform, but depend on interpersonal relationship quality. mPFC IBS may constitute an important neural correlate of hyperbaric-oxygen-related cooperation gains in high-trust dyads.

The orientation of cross-passages is a critical factor for both construction safety and operational efficiency in high-altitude, extra-long tunnels. Currently, systematic theoretical support is lacking for the optimization of cross-passages under complex geological conditions and unique ventilation environments in high-altitude regions. For solving these problems, this research puts forward a "bell-mouthed ("Ba-zi")" arrangement-for intersecting passages, which has an optimized intersection angle &#x3b8;. Through combining ventilation efficiency, expenditure and mechanical reaction, this research adopts the united fluid dynamics and rock mechanics digital simulation frame to investigate the behavior of the tunnel in five cross-passage angle situations (30&#xb0;,40&#xb0;,60&#xb0;,70&#xb0;, and 90&#xb0;), and systematically makes comparison on the comprehensive performance of the tunnel under different cross-passage angles. The 60&#xb0; configuration effectively mitigates localized stress concentrations within the "triangular zone" and substantially curbs surrounding rock deformation. Furthermore, from an aerodynamic standpoint, the 60&#xb0; further optimizes the flow field, yielding the minimum local resistance coefficient, suppresses vortex formation and mitigates gas stagnation zones, facilitating a synergistic alignment of structural integrity, ventilation efficiency, and economic viability. The study establishes a rigorous theoretical framework and offers quantifiable benchmarks for the geometric design of cross-passages in super-long plateau tunnels.

This study aims to investigate the prevalence of serum vitamin D deficiency in the Xining, Qinghai Province (elevation 2260&#xa0;m, oxygen partial pressure 16.10&#xa0;kPa, 36&#xb0;13'-37&#xb0;28'N) and to explore the correlation between 25-hydroxyvitamin D [25(OH)D] levels and inflammatory markers. A total of 2,080 subjects were enrolled, serum 25(OH)D, and inflammatory markers-including procalcitonin (PCT), interleukin 6 (IL-6), and C reactive protein (CRP) -were measured. According to serum 25(OH)D concentrations, participants were divided into three groups: vitamin D sufficiency (>&#x2009;30 ng/mL), insufficiency (20-30 ng/mL), and deficiency (<&#x2009;20 ng/mL). Spearman correlation analysis, partial correlation analysis and Logistic regression analysis were performed. The mean 25(OH)D concentration was 13.99&#x2009;&#xb1;&#x2009;7.20 ng/mL, with the proportions of vitamin D deficiency, insufficiency and sufficiency being 83.65%, 13.65% and 2.70%, respectively. The levels of PCT, IL-6 and CRP in the deficiency group were significantly higher than those in the other two groups (P&#x2009;<&#x2009;0.05). The vitamin D deficiency was higher in females than in males (87.95% vs. 77.47%, P&#x2009;<&#x2009;0.05). The 25(OH)D level peaked in summer and reached the lowest level in winter (P&#x2009;<&#x2009;0.05), while no significant intergroup difference was observed across different age groups. PCT, IL-6 and CRP were significantly negatively correlated with 25(OH)D (r=-0.674, -0.533, -0.292, P&#x2009;<&#x2009;0.01), and these correlations remained significant after adjustment for confounding factors (P&#x2009;<&#x2009;0.01). Logistic regression analysis revealed that female gender (OR&#x2009;=&#x2009;4.043), PCT (OR&#x2009;=&#x2009;2491.808), IL-6 (OR&#x2009;=&#x2009;1.903) and CRP (OR&#x2009;=&#x2009;1.608) were independent risk factors for vitamin D deficiency (P&#x2009;<&#x2009;0.01). Residents in high-altitude Xining suffer from severe vitamin D deficiency correlated with heightened inflammation. Female sex and elevated inflammatory biomarkers independently increase deficiency risk, and seasonal sunlight regulates 25(OH)D levels. Gender- and season-specific vitamin D supplementation could mitigate inflammatory load in highland residents.

Performance in endurance sports is generally linked to aerobic capacity, but this link is less clear in swimming due to its technical complexity and constricted breathing periods. Here, we studied the effect of a moderate acute reduction in blood oxygen transport capacity on middle-distance swimming performance. In a double-blind, randomized crossover design, national-level swimmers (6 men, 6 women; 20&#x2009;&#xb1;&#x2009;2 years; FINA score 604&#x2009;&#xb1;&#x2009;105) completed two 200&#xa0;m front crawl swimming time-trials (TT) on average six days apart, either 30&#xa0;min after rebreathing moderate (men: 1.5&#xa0;ml&#xb7;kg-&#x2009;1, women: 1.2&#xa0;ml&#xb7;kg-&#x2009;1; CO) or small (SHAM) CO dose. Capillary blood lactate and hemoglobin CO binding (%HbCO) were measured before and after the TT. HbCO was ~&#x2009;9% in CO and ~&#x2009;3% in SHAM. Analysis at the group level showed 1.5&#x2009;&#xb1;&#x2009;1.6% longer TT times in CO than in SHAM in men (136.6&#x2009;&#xb1;&#x2009;6.5 vs. 134.5&#x2009;&#xb1;&#x2009;6.2&#xa0;s; p&#x2009;=&#x2009;0.018), whereas there was no significant difference in women. The average increase in blood lactate during TT (10.5-13.5 mmol&#xb7;l-&#x2009;1) did not differ between conditions. Analysis at the individual level showed longer swimming TT times in the CO than in the SHAM condition (range: 1.1 to 5.0&#xa0;s) in eight of the twelve participants. We observed a small negative effect of moderate acute hypoxemia on middle-distance swimming speed in male national-level swimmers, which will have a limited impact on a population basis but can be highly important for an individual competitive swimmer.