Study on the outdoor thermal comfort of college students under different activity intensities in a high-altitude climate zone.

Introduction: Research on the outdoor thermal comfort (OTC) of a university campus is beneficial to the physical and mental health of college students. Methods: In this study, the OTC of students attending Tibet University in Lhasa, which experiences high-altitude cold climate conditions, under different activity intensities was studied using field measurements and a questionnaire survey. Results: With the increase in activity intensity, the comfort physiologically equivalent temperature (PET) value gradually increased in summer, while the comfortable PET value gradually decreased in winter. The most comfortable PET value is 17.6°C in summer and 11.5°C in winter. The neutral PET of Tibetan college students during outdoor activities in summer was 16.3°C, and the neutral PET of outdoor activities in winter was 12.1°C. Gender and ethnicity had different effects on thermal sensation under different activity intensities. Under vigorous-intensity activities, PET in winter and summer had the greatest influence on thermal sensation. The situation was different under moderate-intensity activity. PET had the greatest influence on thermal sensation in summer, and Tmrt had the greatest influence on thermal sensation in winter. Discussion: These findings provide a basis for an improved design of the outdoor environment under different outdoor activity intensities in high-altitude areas.

Effects of three weeks base training at moderate simulated altitude with or without hypoxic residence on exercise capacity and physiological adaptations in well-trained male runners.

Objectives: To test the hypothesis that 'live high-base train high-interval train low' (HiHiLo) altitude training, compared to 'live low-train high' (LoHi), yields greater benefits on performance and physiological adaptations. Methods: Sixteen young male middle-distance runners (age, 17.0 ± 1.5 y; body mass, 58.8 ± 4.9 kg; body height, 176.3 ± 4.3 cm; training years, 3-5 y; training distance per week, 30-60 km.wk-1) with a peak oxygen uptake averaging ~65 ml.min-1.kg-1 trained in a normobaric hypoxia chamber (simulated altitude of ~2,500 m, monitored by heart rate ~170 bpm; thrice weekly) for 3 weeks. During this period, the HiHiLo group (n = 8) stayed in normobaric hypoxia (at ~2,800 m; 10 h.day-1), while the LoHi group (n = 8) resided near sea level. Before and immediately after the intervention, peak oxygen uptake and exercise-induced arterial hypoxemia responses (incremental cycle test) as well as running performance and time-domain heart rate variability (5-km time trial) were assessed. Hematological variables were monitored at baseline and on days 1, 7, 14 and 21 during the intervention. Results: Peak oxygen uptake and running performance did not differ before and after the intervention in either group (all P > 0.05). Exercise-induced arterial hypoxemia responses, measured both at submaximal (240 W) and maximal loads during the incremental test, and log-transformed root mean square of successive R-R intervals during the 4-min post-run recovery period, did not change (all P > 0.05). Hematocrit, mean reticulocyte absolute count and reticulocyte percentage increased above baseline levels on day 21 of the intervention (all P < 0.001), irrespective of group. Conclusions: Well-trained runners undertaking base training at moderate simulated altitude for 3 weeks, with or without hypoxic residence, showed no performance improvement, also with unchanged time-domain heart rate variability and exercise-induced arterial hypoxemia responses.

Uppermost global tree elevations are primarily limited by low temperature or insufficient moisture.

The impact of anthropogenic global warming has induced significant upward dispersal of trees to higher elevations at alpine treelines. Assessing vertical deviation from current uppermost tree distributions to potential treeline positions is crucial for understanding ecosystem responses to evolving global climate. However, due to data resolution constraints and research scale limitation, comprehending the global pattern of alpine treeline elevations and driving factors remains challenging. This study constructed a comprehensive quasi-observational dataset of uppermost tree distribution across global mountains using Google Earth imagery. Validating the isotherm of mean growing-season air temperature at 6.6 ± 0.3°C as the global indicator of thermal treeline, we found that around two-thirds of uppermost tree distribution records significantly deviated from it. Drought conditions constitute the primary driver in 51% of cases, followed by mountain elevation effect which indicates surface heat (27%). Our analyses underscore the multifaceted determinants of global patterns of alpine treeline, explaining divergent treeline responses to climate warming. Moisture, along with temperature and disturbance, plays the most fundamental roles in understanding global variation of alpine treeline elevation and forecasting alpine treeline response to ongoing global warming.

Whole-genome resequencing of Chinese indigenous sheep provides insight into the genetic basis underlying climate adaptation.

BACKGROUND: Chinese indigenous sheep are valuable resources with unique features and characteristics. They are distributed across regions with different climates in mainland China; however, few reports have analyzed the environmental adaptability of sheep based on their genome. We examined the variants and signatures of selection involved in adaptation to extreme humidity, altitude, and temperature conditions in 173 sheep genomes from 41 phenotypically and geographically representative Chinese indigenous sheep breeds to characterize the genetic basis underlying environmental adaptation in these populations. RESULTS: Based on the analysis of population structure, we inferred that Chinese indigenous sheep are divided into four groups: Kazakh (KAZ), Mongolian (MON), Tibetan (TIB), and Yunnan (YUN). We also detected a set of candidate genes that are relevant to adaptation to extreme environmental conditions, such as drought-prone regions (TBXT, TG, and HOXA1), high-altitude regions (DYSF, EPAS1, JAZF1, PDGFD, and NF1) and warm-temperature regions (TSHR, ABCD4, and TEX11). Among all these candidate genes, eight ABCD4, CNTN4, DOCK10, LOC105608545, LOC121816479, SEM3A, SVIL, and TSHR overlap between extreme environmental conditions. The TSHR gene shows a strong signature for positive selection in the warm-temperature group and harbors a single nucleotide polymorphism (SNP) missense mutation located between positions 90,600,001 and 90,650,001 on chromosome 7, which leads to a change in the protein structure of TSHR and influences its stability. CONCLUSIONS: Analysis of the signatures of selection uncovered genes that are likely related to environmental adaptation and a SNP missense mutation in the TSHR gene that affects the protein structure and stability. It also provides information on the evolution of the phylogeographic structure of Chinese indigenous sheep populations. These results provide important genetic resources for future breeding studies and new perspectives on how animals can adapt to climate change.

EEG and fNIRS datasets based on Stroop task during two weeks of high-altitude exposure in new immigrants.

Maintaining sufficient cerebral oxygen metabolism is crucial for human survival, especially in challenging conditions such as high-altitudes. Human cognitive neural activity is sensitive to fluctuations in oxygen levels. However, there is a lack of publicly available datasets on human behavioural responses and cerebral dynamics assessments during the execution of conflicting tasks in natural hypoxic environments. We recruited 80 healthy new immigrant volunteers (males, aged 20 ± 2 years) and employed the Stroop cognitive conflict paradigm. After a two-week exposure to both high and low-altitudes, the behavioural performance, prefrontal oxygen levels, and electroencephalography (EEG) signals were recorded. Comparative analyses were conducted on the behavioural reaction times and accuracy during Stroop tasks, and statistical analyses of participants' prefrontal oxygen levels and EEG signals were performed. We anticipate that our open-access dataset will contribute to the development of monitoring devices and algorithms, designed specifically for measuring cerebral oxygen and EEG dynamics in populations exposed to extreme environments, particularly among individuals suffering from oxygen deficiency.

Existing levels of biodiversity and river location may determine changes from small hydropower developments.

Global ecosystems are facing anthropogenic threats that affect their ecological functions and biodiversity. However, we still lack an understanding of how biodiversity can mediate the responses of ecosystems or communities to human disturbance across spatial gradients. Here, we examined how existing, spatial patterns of biodiversity influence the ecological effects of small hydropower plants (SHPs) on macroinvertebrates in river ecosystems. This study found that levels of biodiversity (e.g., number of species) can influence the degrees of its alterations by SHPs occurring along elevational gradients. The results of the study reveal that the construction of SHPs has various effects on biodiversity. For example, low-altitude areas with low biodiversity (species richness less than 12) showed a small increase in biodiversity compared to high-altitude areas (species richness more than 12) under SHP disturbances. The increases in the effective habitat area of the river segment could be a driver of the enhanced biodiversity in response to SHP effects. Changes in the numerically dominant species contributed to the overall level of community variation from disturbances. Location-specific strategies may mitigate the effects of SHPs and perhaps other disturbances.

Longitudinal multi-omics analysis uncovers the altered landscape of gut microbiota and plasma metabolome in response to high altitude.

BACKGROUND: Gut microbiota is significantly influenced by altitude. However, the dynamics of gut microbiota in relation to altitude remains undisclosed. METHODS: In this study, we investigated the microbiome profile of 610 healthy young men from three different places in China, grouped by altitude, duration of residence, and ethnicity. We conducted widely targeted metabolomic profiling and clinical testing to explore metabolic characteristics. RESULTS: Our findings revealed that as the Han individuals migrated from low altitude to high latitude, the gut microbiota gradually converged towards that of the Tibetan populations but reversed upon returning to lower altitude. Across different cohorts, we identified 51 species specifically enriched during acclimatization and 57 species enriched during deacclimatization to high altitude. Notably, Prevotella copri was found to be the most enriched taxon in both Tibetan and Han populations after ascending to high altitude. Furthermore, significant variations in host plasma metabolome and clinical indices at high altitude could be largely explained by changes in gut microbiota composition. Similar to Tibetans, 41 plasma metabolites, such as lactic acid, sphingosine-1-phosphate, taurine, and inositol, were significantly elevated in Han populations after ascending to high altitude. Germ-free animal experiments demonstrated that certain species, such as Escherichia coli and Klebsiella pneumoniae, which exhibited altitude-dependent variations in human populations, might play crucial roles in host purine metabolism. CONCLUSIONS: This study provides insights into the dynamics of gut microbiota and host plasma metabolome with respect to altitude changes, indicating that their dynamics may have implications for host health at high altitude and contribute to host adaptation. Video Abstract.

Chromosome-level genome assembly of Hippophae tibetana provides insights into high-altitude adaptation and flavonoid biosynthesis.

BACKGROUND: As an endemic shrub of the Qinghai-Tibetan Plateau (QTP), the distribution of Hippophae tibetana Schlecht. ranges between 2800 and 5200 m above sea level. As the most basal branch of the Hippophae genus, H. tibetana has an extensive evolutionary history. The H. tibetana is a valuable tree for studying the ecological evolution of species under extreme conditions. RESULTS: Here, we generated a high-quality chromosome-level genome of H. tibetana. The total size of the assembly genome is 917 Mb. The phylogenomic analysis of 1064 single-copy genes showed a divergence between 3.4 and 12.8 Mya for H. tibetana. Multiple gene families associated with DNA repair and disease resistance were significantly expanded in H. tibetana. We also identified many genes related to DNA repair with signs of positive selection. These results showed expansion and positive selection likely play important roles in H. tibetana's adaptation to comprehensive extreme environments in the QTP. A comprehensive genomic and transcriptomic analysis identified 49 genes involved in the flavonoid biosynthesis pathway in H. tibetana. We generated transgenic sea buckthorn hairy root producing high levels of flavonoid. CONCLUSIONS: Taken together, this H. tibetana high-quality genome provides insights into the plant adaptation mechanisms of plant under extreme environments and lay foundation for the functional genomic research and molecular breeding of H. tibetana.

Consequences of Exposure to Hypobaric Hypoxia Associated with High Altitude on Spermatogenesis and Seminal Parameters: A Literature Review.

Preclinical research has provided compelling evidence indicating that exposure to hypobaric hypoxia (HH) results in a deterioration of spermatogenesis. This adverse effect extends to the underlying molecular mechanisms, progressively leading to impairments in the seminiferous epithelium and germ cells and alterations in semen parameters. Indeed, several studies have demonstrated that animals exposed to HH, whether in natural high-altitude environments or under simulated hypoxic conditions, exhibit damage to the self-renewal and differentiation of spermatogenesis, an increase in germline cell apoptosis, and structural alterations in the seminiferous tubules. One of the primary mechanisms associated with the inhibition of differentiation and an increase in apoptosis among germ cells is an elevated level of oxidative stress, which has been closely associated with HH exposure. Human studies have shown that individuals exposed to HH, such as mountaineers and alpinists, exhibit decreased sperm count, reduced motility, diminished viability, and increased sperm with abnormal morphology in their semen. This evidence strongly suggests that exposure to HH may be considered a significant risk factor that could elevate the prevalence of male infertility. This literature review aims to provide a comprehensive description and propose potential mechanisms that could elucidate the infertility processes induced by HH. By doing so, it contributes to expanding our understanding of the challenges posed by extreme environments on human physiology, opening new avenues for research in this field.

Deciphering the impact of cold-adapted bioinoculants on rhizosphere dynamics, biofortification, and yield of kidney bean across varied altitudinal zones.

Agriculture stands as a thriving enterprise in India, serving as both the bedrock of economy and vital source of nutrition. In response to the escalating demands for high-quality food for swiftly expanding population, agricultural endeavors are extending their reach into the elevated terrains of the Himalayas, tapping into abundant resources for bolstering food production. Nonetheless, these Himalayan agro-ecosystems encounter persistent challenges, leading to crop losses. These challenges stem from a combination of factors including prevailing frigid temperatures, suboptimal farming practices, unpredictable climatic shifts, subdivided land ownership, and limited resources. While the utilization of chemical fertilizers has been embraced to enhance the quality of food output, genuine concerns have arisen due to the potential hazards they pose. Consequently, the present investigation was initiated with the objective of formulating environmentally friendly and cold-tolerant broad ranged bioinoculants tailored to enhance the production of Kidney bean while concurrently enriching its nutrient content across entire hilly regions. The outcomes of this study unveiled noteworthy advancements in kidney bean yield, registering a substantial increase ranging from 12.51 ± 2.39 % to 14.15 ± 0.83 % in regions of lower elevation (Jeolikote) and an even more remarkable surge ranging from 20.60 ± 3.03 % to 29.97 ± 5.02 % in higher elevated areas (Chakrata) compared to the control group. Furthermore, these cold-tolerant bioinoculants exhibited a dual advantage by fostering the enhancement of essential nutrients within the grains and fostering a positive influence on the diversity and abundance of microbial life in the rhizosphere. As a result, to effectively tackle the issues associated with chemical fertilizers and to achieve sustainable improvements in both the yield and nutrient composition of kidney bean across varying elevations, the adoption of cold-tolerant Enterobacter hormaechei CHM16, and Pantoea agglomerans HRM 23, including the consortium, presents a promising avenue. Additionally, this study has contributed significant insights-into the role of organic acids like oxalic acid in the solubilization of nutrients, thereby expanding the existing knowledge in this specialized field.

Hypertension subtypes at high altitude in Peru: Analysis of the Demographic and Family Health Survey 2016-2019.

BACKGROUND: The prevalence of hypertension in Peru has increased over the years. Approximately one third of the Peruvian population lives at high altitudes. This population presents particular physiological, genetic and environmental characteristics that could be related to the prevalence of hypertension and its subtypes. OBJECTIVE: To assess the association between altitude and hypertension in the Peruvian population through an analysis of a nationally representative survey. METHODS: We conducted a cross-sectional analysis of the Demographic and Family Health Survey for the period 2016-2019. We included 122,336 individuals aged 18 years and older. Hypertension was defined according to the JNC-7 guidelines. High-altitude location was defined as a residential cluster located above 2,500 meters above sea level. We utilized generalized linear models from the Poisson family with a log-link function to assess the magnitude of the association between high altitude and hypertension. Additionally, we employed multinomial regression models to analyze the association between high altitude and subtypes of hypertension, including isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), and systolic-diastolic hypertension (SDH). RESULTS: In the adjusted Poisson regression model, we found that the prevalence of hypertension among participants living at high altitudes was lower compared to those living at low altitudes (aPR: 0.89; 95% CI: 0.86-0.93). In the adjusted multinomial regression model, we observed a lower prevalence rate of ISH among participants residing at high altitudes (aRPR: 0.68; 95% CI: 0.61-0.73) and a higher prevalence rate of IDH among participants residing at high altitudes (aRPR: 1.60; 95% CI: 1.32-1.94). CONCLUSIONS: Residents at high altitudes in Peru have a lower prevalence rate of ISH and a higher prevalence rate of IDH compared to those living at low altitudes. Further studies are needed to determine the influence of other biological, environmental, and healthcare access factors on this relationship.

Effects of various living-low and training-high modes with distinct training prescriptions on sea-level performance: A network meta-analysis.

This study aimed to separately compare and rank the effect of various living-low and training-high (LLTH) modes on aerobic and anaerobic performances in athletes, focusing on training intensity, modality, and volume, through network meta-analysis. We systematically searched PubMed, Web of Science, Embase, EBSCO, and Cochrane from their inception date to June 30, 2023. Based on the hypoxic training modality and the intensity and duration of work intervals, LLTH was divided into intermittent hypoxic exposure, continuous hypoxic training, repeated sprint training in hypoxia (RSH; work interval: 5-10 s and rest interval: approximately 30 s), interval sprint training in hypoxia (ISH; work interval: 15-30 s), short-duration high-intensity interval training (s-IHT; short work interval: 1-2 min), long-duration high-intensity interval training (l-IHT; long work interval: > 5 min), and continuous and interval training under hypoxia. A meta-analysis was conducted to determine the standardized mean differences (SMDs) among the effects of various hypoxic interventions on aerobic and anaerobic performances. From 2,072 originally identified titles, 56 studies were included in the analysis. The pooled data from 53 studies showed that only l-IHT (SMDs: 0.78 [95% credible interval; CrI, 0.52-1.05]) and RSH (SMDs: 0.30 [95% CrI, 0.10-0.50]) compared with normoxic training effectively improved athletes' aerobic performance. Furthermore, the pooled data from 29 studies revealed that active intermittent hypoxic training compared with normoxic training can effectively improve anaerobic performance, with SMDs ranging from 0.97 (95% CrI, 0.12-1.81) for l-IHT to 0.32 (95% CrI, 0.05-0.59) for RSH. When adopting a program for LLTH, sufficient duration and work intensity intervals are key to achieving optimal improvements in athletes' overall performance, regardless of the potential improvement in aerobic or anaerobic performance. Nevertheless, it is essential to acknowledge that this study incorporated merely one study on the improvement of anaerobic performance by l-IHT, undermining the credibility of the results. Accordingly, more related studies are needed in the future to provide evidence-based support. It seems difficult to achieve beneficial adaptive changes in performance with intermittent passive hypoxic exposure and continuous low-intensity hypoxic training.

Responses of leaf traits to altitude in Quercus aquifolioides and Sorbus rehderiana on the eastern edge of the Qinghai-Tibet Plateau, China.

As the most senstitive plant organs to environmental changes, leaves serve as crucial indicators of plant survival strategies. We measured the morphology, anatomical traits, gas exchange parameters, and chlorophyll fluorescence parameters of Quercus aquifolioides (evergreen broad-leaved) and Sorbus rehderiana (deciduous broad-leaved) at altitudes of 2600, 2800, 3000, 3200 and 3400 m on the eastern edge of the Qinghai-Tibet Plateau, China. We explored the similarity and difference in their responses to altitude change and the ecological adaptation strategy. The results showed that as the altitude increased, leaf dry matter content of Q. aquifolioides decreased, that of S. rehderiana increased, leaf size for both species gradually decreased, and the palisade coefficient of Q. aquifolioides showed a decreasing trend, contrasting with the increasing trend in S. rehderiana. As the altitude increased, the thickness of leaves, palisade tissue, spongy tissue, upper epidermis, and lower epidermis of both species increased significantly, with the increment of 22.4%, 4.9%, 45.1%, 23.3%, 19.6%, and 28.2%, 46.9%, 8.9%, 25.9%, 20.8% at altitude of 3400 m, respectively, compared with the altitude of 2600 m. The gas exchange and chlorophyll fluorescence parameters of S. rehderiana significantly increased with increasing altitude, while Q. aquifolioides showed the opposite trend. Leaf anatomical traits, gas exchange, and chlorophyll fluorescence parameters of both species displayed considerable plasticity. There were significant correlations among most leaf traits and between leaf traits and altitude. The survival strategy of Q. aquifolioides was more conservative in response to altitude changes, while that of S. rehderiana was more active. Both species adapted to different altitudes by adjusting their own traits.

[Silica exposure among miners at high altitude. Inhaled dose and evaluation methods in hypobaric environments]. / Exposición a sílice de mineros en altitud. Dosis inhalada, método de evaluación en condición de hipobaria.

OBJECTIVE: To evaluate silica exposure among Chilean miners at high altitude, using different methodological approaches, for the purpose of determining the safest method to control exposures.  Methods: The 46 miners in the sample worked at 3000 meters above sea level in nonstandard work shifts, consisting of four consecutive 12-hour days, followed by four consecutive days off. Silica samples were obtained in each of the jobs positions of these 46 high-altitude miners. The results of the concentrations are presented in mg/m3. Exposures were evaluated in compatison to the Threshold Limit Value (Method 1) and using two other methodologies that incorporate respiratory parameters (Methods 2 and 3). The proportion of miners at risk was determined with each of these methods and compared. RESULTS: Based on the Threshold Limit Value (Method 1), 43.48% of miners were classified as being at risk. With the other two methods that incorporate respiratory parameters, the proportion of overexposed miners was 82.61% with Method 2, and 73.91% with Method 3. CONCLUSIONS: Of the three methods analyzed, the one that considers the respiratory parameter minute volume, through the estimation of the inhaled dose, is the safest to define the group of miners at risk due to exposure to silica at high altitude.

OBJETIVO: Evaluar la exposición a sílice de mineros chilenos en altitud usando diferentes metodologías, con el propósito de determinar el método más seguro para controlar la exposición.  Métodos: Los 46 mineros que conforman la muestra trabajan a 3000 metros sobre el nivel del mar con sistema de turnos no convencionales, en jornadas de 12 horas diarias por 4 días consecutivos, después de los cuales se descansa por otros 4 días. Se tomaron muestras de sílice en cada uno de los puestos de trabajo de estos 46 mineros en altitud. Los resultados de las concentraciones se presentan en (mg/m3). La exposición se evaluó usando el Threshold Limit Value y otras dos metodologías que incorporan parámetros respiratorios. Se determinó el grupo de mineros en riesgo con cada uno de estos métodos y se comparó la proporción de mineros expuestos en cada caso. RESULTADOS: evaluando con el Threshold Limit Value (método 1) se obtuvo un 43,48% de mineros en riesgo. Con los métodos que incluyen parámetros respiratorios se obtuvo una proporción de mineros sobre-expuestos del 82,61% con el método 2, y 73,91% con el método 3. CONCLUSIONES: de los tres métodos analizados, el que considera el parámetro respiratorio volumen minuto, a través de la estimación de la dosis inhalada, es el más seguro para definir el grupo de mineros en riesgo por exposición a sílice a gran altura.

Left ventricular strain changes at high altitude in rats: a cardiac magnetic resonance tissue tracking imaging study.

BACKGROUND: Long-term exposure to a high altitude environment with low pressure and low oxygen could cause abnormalities in the structure and function of the heart. Myocardial strain is a sensitive indicator for assessing myocardial dysfunction, monitoring myocardial strain is of great significance for the early diagnosis and treatment of high altitude heart-related diseases. This study applies cardiac magnetic resonance tissue tracking technology (CMR-TT) to evaluate the changes in left ventricular myocardial function and structure in rats in high altitude environment. METHODS: 6-week-old male rats were randomized into plateau hypoxia rats (plateau group, n = 21) as the experimental group and plain rats (plain group, n = 10) as the control group. plateau group rats were transported from Chengdu (altitude: 360 m), a city in a plateau located in southwestern China, to the Qinghai-Tibet Plateau (altitude: 3850 m), Yushu, China, and then fed for 12 weeks there, while plain group rats were fed in Chengdu(altitude: 360 m), China. Using 7.0 T cardiac magnetic resonance (CMR) to evaluate the left ventricular ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV) and stroke volume (SV), as well as myocardial strain parameters including the peak global longitudinal (GLS), radial (GRS), and circumferential strain (GCS). The rats were euthanized and a myocardial biopsy was obtained after the magnetic resonance imaging scan. RESULTS: The plateau rats showed more lower left ventricular GLS and GRS (P < 0.05) than the plain rats. However, there was no statistically significant difference in left ventricular EDV, ESV, SV, EF and GCS compared to the plain rats (P > 0.05). CONCLUSIONS: After 12 weeks of exposure to high altitude low-pressure hypoxia environment, the left ventricular global strain was partially decreased and myocardium is damaged, while the whole heart ejection fraction was still preserved, the myocardial strain was more sensitive than the ejection fraction in monitoring cardiac function.

Knowledge, attitude, and practice of atrial fibrillation in high altitude areas.

Background: To investigate the knowledge, attitude, and practice (KAP) of atrial fibrillation (AF) among the general population in high-altitude areas. Methodology: A web-based cross-sectional study was conducted among the general population in high-altitude areas. Results: A total of 786 valid questionnaires were enrolled, with a mean age of 34.75 ± 14.16 years. The mean score of knowledge, attitude and practice were 8.22 ± 6.50 (possible range: 0-10), 28.90 ± 5.63 (possible range: 8-40), 34.34 ± 6.44 (possible range: 9-45), respectively. The multivariate analysis showed that knowledge scores (OR = 1.108, 95% CI = 1.075-1.142, p < 0.001), attitude scores (OR = 1.118, 95% CI = 1.081-1.156, p < 0.001), and never smoking (OR = 2.438, 95% CI = 1.426-4.167, p = 0.001) were independently associated with proactive practice. The structural equation modeling (SEM) showed direct effect of knowledge on practice (p = 0.014), and attitude on practice (p = 0.004), while no effect of knowledge on attitude (p = 0.190). Conclusion: The general population in high-altitude regions had adequate knowledge, positive attitude, and proactive practice towards AF. The SEM was suitable for explaining general population' KAP regarding AF, revealing that knowledge directly and positively affected attitude and practice.

Silicone Oil Tamponade for Therapy of Primary Retinal Detachment in Patients Who Live at High Altitudes.

BACKGROUND: Uncomplicated rhegmatogenous retinal detachment (RRD) is mainly treated with vitrectomy and gas tamponade or, alternatively, scleral buckling surgery. However, gas tamponade inflates at high altitudes, causing significant complications. Silicone oil (SO) tamponade volume is unaffected by atmospheric pressure and may be used in patients who live or must undertake travel at high altitudes. PURPOSE: To determine the anatomical and functional outcomes after pars plana vitrectomy (PPV) with SO tamponade in primary uncomplicated RRD. METHODS: Twenty-eight consecutive cases of patients operated between January 2017 and December 2022 in Jules-Gonin University Eye Hospital in Lausanne were included in this retrospective study. All patients had a follow-up of at least 3 months after SO removal. RESULTS: Primary reattachment was achieved in all 28 eyes. Mean follow-up was 17.2 months (range: 3 - 51 months) after SO removal. Mean age at the time of intervention was 60 years (range: 21 - 80 years). Vision was stabilized or improved in 27 eyes (96%). One patient demonstrated a slight visual acuity decrease due to cataract formation at the last follow-up. In all patients, SO was removed 2 to 5 months after primary repair. In 14 of the 21 phakic patients, concomitant cataract surgery was performed. No surgical complications were encountered. Postoperatively, 5 (18%) patients had ocular hypertension, presumably steroid related, that was successfully controlled with topical treatment. CONCLUSION: PPV with SO injection seems to be a safe and efficient surgical approach in the treatment of primary uncomplicated RRD in patients living at high altitudes and was associated with good anatomical and functional outcome in our series. However, the need for a follow-up surgery to remove SO should be weighed in these cases.

Exome sequencing in extreme altitude mountaineers identifies pathogenic variants in RTEL1 and COL6A1 previously associated with respiratory failure.

Adaptation of humans to challenging environmental conditions, such as extreme temperature, malnutrition, or hypoxia, is an interesting phenomenon for both basic and applied research. Identification of the genetic factors contributing to human adaptation to these conditions enhances our understanding of the underlying molecular and physiological mechanisms. In our study, we analyzed the exomes of 22 high altitude mountaineers to uncover genetic variants contributing to hypoxic adaptation. To our surprise, we identified two putative loss-of-function variants, rs1385101139 in RTEL1 and rs1002726737 in COL6A1 in two extremely high altitude (personal record of more than 8500 m) professional climbers. Both variants can be interpreted as pathogenic according to medical geneticists' guidelines, and are linked to inherited conditions involving respiratory failure (late-onset pulmonary fibrosis and severe Ullrich muscular dystrophy for rs1385101139 and rs1002726737, respectively). Our results suggest that a loss of gene function may act as an important factor of human adaptation, which is corroborated by previous reports in other human subjects.

[Prevalence and Influencing Factors of Isolated Diastolic Hypertension in Tibetan Population in Tibet]. / è¥¿è—åœ°åŒºè—æ—äººç¾¤å•çº¯èˆ’å¼ æœŸé«˜è¡€åŽ‹çš„æ‚£ç— çŽ°çŠ¶åŠå ¶å½±å“å› ç´ åˆ†æž.

Objective: To investigate the prevalence and influencing factors of isolated diastolic hypertension (IDH) in the Tibetan population in Tibet and to provide some evidence for the prevention and control of hypertension and other related diseases in high-altitude areas. Methods: A multistage stratified whole-group random sampling method was used to enroll participants from Ngari Prefecture, Nagqu City, Shannan City, and Lhasa City, Tibet. A total of 3918 native Tibetans with complete data were enrolled in the survey between June 2020 and August 2023. The participants were aged from 18 to 80. The demographic data, life habits, and chronic disease prevalence of the participants were collected. Fasting venous blood samples were collected to perform the routine blood tests and blood biochemistry tests. The prevalence of IDH in subgroups with different characteristics was analyzed and the influencing factors were analyzed by multivariate logistic regression, accordingly. The predictive value of influencing factors on the prevalence of IDH was analyzed by the receiver operating characteristic (ROC) curve and the findings were compared with those of the previous prediction models for IDH. Results: The prevalence of hypertension in the participants was 33.7% (n=1321), among which, 395 had IDH, accounting for 29.9% of the hypertensive patients. The results of multivariate regression showed that age, heart rate, body mass index, waist circumference, hemoglobin, and low-density lipoprotein cholesterol were associated with risks of developing IDH (P<0.05). The area under the ROC curve (AUC) was 0.71, which indicated improved accuracy for predicting the risks for IDH in comparison with previous predictive models for IDH. Among the influencing factors, BMI showed the best predictive value for IDH risks. Conclusion: The prevalence of IDH is high among Tibetans in Tibet, suggesting the necessity for rational allocation of health resources in accordance. Compared with the previous IDH prediction models, the model proposed in this study is more suited for the Tibetan population. Targeted interventions should be carried out for the high-risk populations, such as young and middle-aged adults and populations suffering from overweight/obesity, central obesity, high-altitude polycythemia, and dyslipidemia, so as to effectively control the occurrence and development of IDH.

Relationship between leaf vein traits of three dominant Quercus species and ecological factors in the Qinling Mountains, China.

We investigated the inter- and intra-species differences of leaf vein traits of three dominant Quercus species, Q. wutaishanica, Q. aliena var. acutiserrata, and Q. variabilis of Niubeiling (subtropical humid climate) and Taohuagou (warm temperate semi-humid climate), located in the eastern and western Qinling Mountains. The nine examined leaf vein traits included primary leaf vein width, secondary leaf vein width, mean fine vein width, primary vein density, fine vein density, vein areole diameter, areole density, 3D fine vein surface area, and fine vein volume. We further elucidated the influencing mechanisms and regulatory pathways of biotic and abiotic factors on leaf vein traits. The results showed that species identity had significant effects on eight out of nine leaf vein traits except 3D fine vein surface area, while habitat had significant effects on primary leaf vein width, secondary leaf vein width, vein areole diameter, fine vein density, and areole density. Altitude had significant effects on primary vein density, mean fine vein width, vein areole diameter, fine vein density and areole density. Habitat, tree species identity, and altitude had significantly interactive effects on primary leaf vein density, 3D fine vein surface area, and fine vein volume. There were significant differences in primary leaf vein width, mean fine vein width, areole density, 3D fine vein surface area, fine vein volume, primary vein density of Q. wutaishanica between the two studied habitats, but the differences were only found in secondary leaf vein width and areole density of Q. aliena var. acutiserrata and Q. variabilis. The examined leaf vein traits were influenced both by biotic and abiotic factors, with varying effect sizes. Among the biotic factors, petiole length, leaf length and width ratio had strong effect on leaf vein traits. Among the abiotic factors, climatic and soil factors had high effect size on vein traits, with the former being higher than the latter. Leaf vein traits were affected directly by biotic factors, but indirectly by abiotic factors (soil and climatic factors) via regulating biotic factors (leaf stoichiometry and leaf phenotypic traits).