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European Journal of Sport Science Jun 2024We examine the impact of the acute manipulation of oxygen availability during discrete phases (active and passive) of a repeated-sprint cycling protocol on performance,...
We examine the impact of the acute manipulation of oxygen availability during discrete phases (active and passive) of a repeated-sprint cycling protocol on performance, physiological, and perceptual responses. On separate days, twelve trained males completed four sets of five 5-s 'all out' cycle sprints (25-s inter-sprint recovery and 5-min interset rest) in four randomized conditions: normobaric hypoxia (inspired oxygen fraction of 12.9%) applied continuously (C-HYP), intermittently during only the sets of sprints (I-HYP) or between-sets recovery periods (I-HYP), or not at all (C-NOR). Peak and mean power output, peripheral oxygen saturation, heart rate, blood lactate concentration, exercise-related sensations, and vastus lateralis muscle oxygenation using near-infrared spectroscopy were assessed. Peak and mean power output was ∼4%-5% lower for C-HYP compared to C-NOR (P ≤ 0.050) and I-HYP (P ≤ 0.027). Peripheral oxygen saturation was lower during C-HYP and I-HYP compared with C-NOR and I-HYP during sets of sprints (∼83-85 vs. ∼95%-97%; P < 0.001), while lower values were obtained for C-HYP and I-HYP than C-NOR and I-HYP during between-sets rest period (∼84-85 vs. ∼96%; P < 0.001). Difficulty in breathing was ∼21% higher for C-HYP than C-NOR (P = 0.050). Ratings of perceived exertion (P = 0.435), limb discomfort (P = 0.416), heart rate (P = 0.605), blood lactate concentration (P = 0.976), and muscle oxygenation-derived variables (P = 0.056 to 0.605) did not differ between conditions. In conclusion, the method of hypoxic exposure application (continuous vs. intermittent) affects mechanical performance, while internal demands remained essentially comparable during repeated cycle sprints.
PubMed: 38874584
DOI: 10.1002/ejsc.12146 -
Heliyon Jun 2024Understanding the combining ability effects, heterosis, and genetic relationships between parental lines would be helpful in the maize breeding program to develop...
Understanding the combining ability effects, heterosis, and genetic relationships between parental lines would be helpful in the maize breeding program to develop high-yielding and genetically stable maize varieties for various contrasting environments. Hence, the objective of this study was to estimate combining ability effects, heterosis, genetic distance (GD) and associations for grain yield and other agronomic traits. Forty-five F diallel crosses, four commercial checks, and ten inbred lines were evaluated at Bako and Jima Agricultural Research Centers, Ethiopia. Significant differences were observed among environments, genotypes and genotype by environment interaction for grain yield and almost all studied agronomic traits. Combining ability analysis showed both additive and non-additive gene effects significantly controlled grain yield and all other studied traits. The preponderance of general combining ability (GCA) effects indicates the importance of additive gene action inheriting most agronomic traits. Lines L2, L7, and L9 were the best combiners for grain yield, whereas lines L3 and L4 had desirable GCA values to improve days to flowering and plant height. Among the top ten crosses, L6 × L9, L6 × L7 and L4 × L9 were good specific combiners and had 18.8 %, 17.2 % and 16.2 % grain yield advantage over the best check, BH546. These hybrids also had high mid and better-parent heterosis compared with other crosses. The associations of GD with mean of F and SCA effects were positive and highly significant for grain yield and some other traits. In contrast, correlations of GD with mid and better parent heterosis were non-significant for grain yield and most other traits. The results of this study are particularly useful for breeders who envisage combining conventional and molecular methods.
PubMed: 38873668
DOI: 10.1016/j.heliyon.2024.e32267 -
Frontiers in Neurorobotics 2024Unmanned Aerial Vehicles (UAVs) and quadrotors are being used in an increasing number of applications. The detection and management of forest fires is continually...
Unmanned Aerial Vehicles (UAVs) and quadrotors are being used in an increasing number of applications. The detection and management of forest fires is continually improved by the incorporation of new economical technologies in order to prevent ecological degradation and disasters. Using an inner-outer loop design, this paper discusses an attitude and altitude controller for a quadrotor. As a highly nonlinear system, quadrotor dynamics can be simplified by assuming several assumptions. Quadrotor autopilot is developed using nonlinear feedback linearization technique, LQR, SMC, PD, and PID controllers. Often, these approaches are used to improve control and to reject disturbances. PD-PID controllers are also deployed in the tracking and surveillance of smoke or fire by intelligent algorithms. In this paper, the efficiency using a combined PD-PID controllers with adjustable parameters have been studied. The performance was assessed by simulation using matlab Simulink. The computational study conducted to assess the proposed approach showed that the PD-PID combination presented in this paper yields promising outcomes.
PubMed: 38873025
DOI: 10.3389/fnbot.2024.1363366 -
Health Science Reports Jun 2024Acute respiratory failure (ARF) is the most frequent cause of cardiorespiratory arrest and subsequent death in children worldwide. There have been limited studies...
BACKGROUND AND AIMS
Acute respiratory failure (ARF) is the most frequent cause of cardiorespiratory arrest and subsequent death in children worldwide. There have been limited studies regarding ARF in high altitude settings. The aim of this study was to calculate mortality and describe associated factors for severity and mortality in children with ARF.
METHODS
The study was conducted within a prospective multicentric cohort that evaluated the natural history of pediatric ARF. For this analysis three primary outcomes were studied: mortality, invasive mechanical ventilation, and pediatric intensive care unit (PICU) length of stay. Eligible patients were children older than 1 month and younger than 18 years of age with respiratory difficulty at the time of admission. Patients who developed ARF were followed at the time of ARF, 48 h later, at the time of discharge, and at 30 and 60 days after discharge. It was conducted in the pediatric emergency, in-hospital, and critical-care services in three hospitals in Bogotá, Colombia, from April 2020 to June 2021.
RESULTS
Out of a total of 685 eligible patients, 296 developed ARF for a calculated incidence of ARF of 43.2%. Of the ARF group, 90 patients (30.4%) needed orotracheal intubation, for a mean of 9.57 days of ventilation (interquartile range = 3.00-11.5). Incidence of mortality was 6.1% ( = 18). The associated factors for mortality in ARF were a history of a neurologic comorbidity and a higher fraction of inspired oxygen at ARF diagnosis. For PICU length of stay, the associated factors were age between 2 and 5 years of age, exposure to smokers, and respiratory comorbidity. Finally, for mechanical ventilation, the risk factors were obesity and being unstable at admission.
CONCLUSIONS
ARF is a common cause of morbidity and mortality in children. Understanding the factors associated with greater mortality and severity of ARF might allow earlier recognition and initiation of prompt treatment strategies.
PubMed: 38872789
DOI: 10.1002/hsr2.1994 -
ELife Jun 2024Compared with lowlander migrants, native Tibetans have a higher reproductive success at high altitude though the underlying mechanism remains unclear. Here, we compared...
Compared with lowlander migrants, native Tibetans have a higher reproductive success at high altitude though the underlying mechanism remains unclear. Here, we compared the transcriptome and histology of full-term placentas between native Tibetans and Han migrants. We found that the placental trophoblast shows the largest expression divergence between Tibetans and Han, and Tibetans show decreased immune response and endoplasmic reticulum stress. Remarkably, we detected a sex-biased expression divergence, where the male-infant placentas show a greater between-population difference than the female-infant placentas. The umbilical cord plays a key role in the sex-biased expression divergence, which is associated with the higher birth weight of the male newborns of Tibetans. We also identified adaptive histological changes in the male-infant placentas of Tibetans, including larger umbilical artery wall and umbilical artery intima and media, and fewer syncytial knots. These findings provide valuable insights into the sex-biased adaptation of human populations, with significant implications for medical and genetic studies of human reproduction.
Topics: Humans; Female; Placenta; Male; Pregnancy; Fetal Development; Tibet; Infant, Newborn; Transcriptome; Altitude; Sex Factors; Sex Characteristics
PubMed: 38869160
DOI: 10.7554/eLife.89004 -
Heliyon Jun 2024The agricultural sector, in particular viticulture, is highly susceptible to variations in the environment, crop conditions, and operational factors. Effectively...
The agricultural sector, in particular viticulture, is highly susceptible to variations in the environment, crop conditions, and operational factors. Effectively managing these variables in the field necessitates observation, measurement, and responsive actions. Leveraging new technologies within the realm of precision agriculture, vineyards can enhance their long-term efficiency, productivity, and profitability. In our work we propose a novel analysis of the impact of pedoclimatic factors on wine, with a case study focusing on the Denomination of Controlled and Guaranteed Origin Chianti Classico (DOCG), a prime wine-producing region located in Tuscany, between the provinces of Siena and Florence. We first collected a novel dataset, where geographic information as well as wine quality information were collected, using publicly available sources. Using such geographic information retrieved and an unsupervised machine learning approach, we conducted an in-depth examination of pedoclimatic and production data. To collect the whole set of possibly relevant features, we first assessed the region's morphological attributes, including altitude, exposure, and slopes, while pinpointing individual wineries. Subsequently we then calculated crucial viticultural indices such as the Winkler, Huglin, Fregoni, and Freshness Index by utilizing daily temperature records from Chianti Classico, and we further related them to an assessment of wine quality. In addition to this, we designed and distributed a survey conducted among a sample of wineries situated in the Chianti Classico area, obtaining valuable insights into local data. The primary goal of this study is to elucidate the interrelationships between various parameters associated with the region, considering influential factors such as the environment, viticulture, and field operations that significantly impact wine production. By doing so, wineries could potentially unlock the full potential of their resources. In fact, through the unsupervised and correlation analysis we could elucidate the relationships existing between the pedoclimatic parameters of the region, considering the most important factors such as viticulture and field operations, and relate them to wine quality as for instance using the survey data collected. This study represents an unprecedent in the literature, and it could pave the path for future studies focusing on the importance of climatic factors into production and quality of wines.
PubMed: 38868017
DOI: 10.1016/j.heliyon.2024.e31648 -
Journal of Lipid Research Jun 2024Lipids are components of cytomembranes that are involved in various biochemical processes. High-altitude hypoxic environments not only affect the body's energy...
Lipids are components of cytomembranes that are involved in various biochemical processes. High-altitude hypoxic environments not only affect the body's energy metabolism, but these environments can also cause abnormal lipid metabolism involved in the hypoxia-induced cognitive impairment. Thus, comprehensive lipidomic profiling of the brain tissue is an essential step toward understanding the mechanism of cognitive impairment induced by hypoxic exposure. In the present study, mice showed reduced new-object recognition and spatial memory when exposed to hypobaric hypoxia for 1 day. Histomorphological staining revealed significant morphological and structural damage to the hippocampal tissue, along with prolonged exposure to hypobaric hypoxia. Dynamic lipidomics of the mouse hippocampus showed a significant shift in both the type and distribution of phospholipids, as verified by spatial lipid mapping. Collectively, these results have provided new insights into the cognitive decline induced by high altitude, in which alterations in lipid metabolism may be an important contributing factor.
PubMed: 38866327
DOI: 10.1016/j.jlr.2024.100575 -
PloS One 2024We investigated the effect of tactile guided slow deep breathing compared with that of spontaneous breathing on blood oxygen saturation (SpO2), alertness, and hypoxia...
We investigated the effect of tactile guided slow deep breathing compared with that of spontaneous breathing on blood oxygen saturation (SpO2), alertness, and hypoxia symptoms during acute hypobaric hypoxia. We also evaluated the usability of this tactile breathing guidance. Twelve male military pilots were exposed to a simulated altitude of 4,572 m (15,000 ft) in a repeated measures study while breathing spontaneously and during tactile guided slow deep breathing. Under both breathing conditions, measurements were performed at rest and during the performance of a cognitive task. The Stanford Sleepiness Scale was used to rate alertness, and hypoxia symptoms were reported using a list of general hypoxia symptoms. Usability was evaluated in a questionnaire. Tactile guidance of slow deep breathing significantly increased (p <.001) the SpO2 - 88% (95% confidence interval (CI) [84%, 91%]) at rest and 85% (95% CI [81%, 88%]) during the cognitive task - compared with spontaneous breathing - 78% (95% CI [75%, 81%]) at rest and 78% (95% CI [76%, 80%]) during the cognitive task. This increase in SpO2 had no effect on the level of alertness and number of hypoxia symptoms. Pilots were positive about the intensity and sensation of the vibration signal, but had difficulty following the vibration pattern during the cognitive task. Pre-training may improve slow deep breathing technique during performance of cognitive tasks.
Topics: Humans; Male; Hypoxia; Adult; Oxygen Saturation; Respiration; Military Personnel; Touch; Cognition; Young Adult; Pilots; Altitude
PubMed: 38865320
DOI: 10.1371/journal.pone.0302564 -
Cureus May 2024A 15-month-old African American male patient presented to the pediatric clinic to establish care. The patient had been seen and treated by a previous pediatrician who...
A 15-month-old African American male patient presented to the pediatric clinic to establish care. The patient had been seen and treated by a previous pediatrician who had diagnosed him with failure to thrive, anemia, and hepatosplenomegaly, according to the patient's parents. Upon physical examination, the patient was determined to be less than the first percentile for height and in the eighth percentile for weight. Frontal bossing was also observed. The patient's hemoglobin level was measured in the office to help confirm the previous anemia diagnosis and was determined to be 6.3 g/dL (normal: 10.5-13.0 g/dL). At this point, the patient was sent to a pediatric emergency department for continued treatment and workup. At the emergency department, the patient received an extensive laboratory workup for the evaluation of anemia, revealing iron deficiency anemia (hemoglobin: 5.6 g/dL (normal: 10.5-13 g/dL), mean corpuscular volume: 51.4 fl (normal: 70-84 fl), iron: 18 mcg/dL (normal: 30-70 mcg/dL), total iron binding capacity: 598 mcg/dL (normal: 100-400 mcg/dL), and hematocrit: 23.7% (normal: 33-38%)) and decreased levels of vitamin D (<6 ng/mL, normal: >30 ng/mL), ionized calcium (1.17 mg/dL, normal: 4.4-5.2 mg/dL), and phosphorus (2.4 mg/dL, normal: 2.9-5.9 mg/dL). These studies, paired with X-ray images of the patient's shoulders and wrists, further confirmed the diagnosis of rickets. Rickets is a disease in pediatric patients defined as a condition in which the mineralization of epiphyseal plates is defective. A nutritional deficiency in vitamin D, calcium, or phosphate causes acquired rickets. This condition is most commonly found in developing countries; some predisposing factors include poor sun exposure, high altitude, and breastfeeding. The patient was seen in the outpatient pediatric setting after the hospitalization, in which he received a blood transfusion, where he was managed on supplementation of calcium carbonate suspension, polysaccharide iron complex/novaferrum drops, and cholecalciferol drops with referral to endocrinology, hematology, and dietetics. This case serves as an example of how the diagnosis of nutritional deficiencies, such as rickets, can also be found in developed countries like the United States. Other conditions considered in the differential diagnosis were cystic fibrosis, necrotizing enterocolitis, metabolic disorders, inadequate absorption, and mechanical feeding difficulties, each of which must be ruled out to ensure that even an unlikely finding was not missed.
PubMed: 38864063
DOI: 10.7759/cureus.60140 -
Communications Biology Jun 2024Telomeres are repetitive nucleoprotein complexes at chromosomal termini essential for maintaining genome stability. Telomeric RNA, or TERRA, is a previously presumed...
Telomeres are repetitive nucleoprotein complexes at chromosomal termini essential for maintaining genome stability. Telomeric RNA, or TERRA, is a previously presumed long noncoding RNA of heterogeneous lengths that contributes to end-capping structure and function, and facilitates telomeric recombination in tumors that maintain telomere length via the telomerase-independent Alternative Lengthening of Telomeres (ALT) pathway. Here, we investigated TERRA in the radiation-induced DNA damage response (DDR) across astronauts, high-altitude climbers, healthy donors, and cellular models. Similar to astronauts in the space radiation environment and climbers of Mt. Everest, in vitro radiation exposure prompted increased transcription of TERRA, while simulated microgravity did not. Data suggest a specific TERRA DDR to telomeric double-strand breaks (DSBs), and provide direct demonstration of hybridized TERRA at telomere-specific DSB sites, indicative of protective TERRA:telomeric DNA hybrid formation. Targeted telomeric DSBs also resulted in accumulation of TERRA foci in G2-phase, supportive of TERRA's role in facilitating recombination-mediated telomere elongation. Results have important implications for scenarios involving persistent telomeric DNA damage, such as those associated with chronic oxidative stress (e.g., aging, systemic inflammation, environmental and occupational radiation exposures), which can trigger transient ALT in normal human cells, as well as for targeting TERRA as a therapeutic strategy against ALT-positive tumors.
Topics: Humans; Altitude; Telomere; Space Flight; Male; RNA, Long Noncoding; Adult; Middle Aged; DNA Breaks, Double-Stranded; Female; DNA Damage; Mountaineering; Telomere Homeostasis
PubMed: 38862827
DOI: 10.1038/s42003-024-06014-x