Sufficient sleep duration and good sleep quality are crucial to ensure normal physical and mental health, cognition and work performance for the common people, as well as astronauts. On-orbit sleep problem is very com...Sufficient sleep duration and good sleep quality are crucial to ensure normal physical and mental health, cognition and work performance for the common people, as well as astronauts. On-orbit sleep problem is very common among astronauts and has potential detrimental influences on the health of crewmembers and the safety of flight missions. Sleep in space is becoming a new medical research frontier. In this review we summarized on-orbit sleep problems of astronauts and six kinds of causes, and we presented the effects of lack of sleep on performance as well as mental and physical health, then we proposed seven kinds of countermeasures for sleep disturbance in spaceflight, including pharmacologic interventions, light treatment, crew selection and training, Traditional Chinese Medicine and so on. Furthermore, we discussed and oriented the prospect of researches on sleep in space.展开更多
The circadian clock and sleep are essential for human physiology and behavior; deregulation of circadian rhythms impairs health and performance. Circadian clocks and sleep evolved to adapt to Earth's environment, ...The circadian clock and sleep are essential for human physiology and behavior; deregulation of circadian rhythms impairs health and performance. Circadian clocks and sleep evolved to adapt to Earth's environment, which is characterized by a 24-hour light–dark cycle. Changes in gravity load, lighting and work schedules during spaceflight missions can impact circadian clocks and disrupt sleep, in turn jeopardizing the mood, cognition and performance of orbiting astronauts. In this review, we summarize our understanding of both the influence of the space environment on the circadian timing system and sleep and the impact of these changes on astronaut physiology and performance.展开更多
In 2021,China Space Station(CSS)was assembled and constructed in-orbit,which provided a broad space platform for space medicine and space life sciences research.Space medicine focuses on the systematic risks that rest...In 2021,China Space Station(CSS)was assembled and constructed in-orbit,which provided a broad space platform for space medicine and space life sciences research.Space medicine focuses on the systematic risks that restrict long-term manned spaceflight.It carries out systematic research on the impact and countermeasure technology of long-term weightlessness on astronauts’health,space radiation on astronauts’health,behavior and ability,advanced on-orbit monitoring and medical disposal technology,and traditional space medical application technology by the space medicine experiment platform on human body and cell.It has accumulated valuable data on space environmental effects and human factors research,established a“human system risk”research system,obtained new knowledge and discoveries of space medicine,and explored countermeasure technologies of new characteristics.Moreover,a series of achievements have been made in the basic research on the mechanism of the special space environmental effect,which provides a solid foundation for the implementation of space missions.展开更多
Background: Low back pain is the most common spinal disorder among soldiers, and load carriage training(LCT) is considered the main cause. We aimed to investigate changes in the spine system of soldiers after LCT at h...Background: Low back pain is the most common spinal disorder among soldiers, and load carriage training(LCT) is considered the main cause. We aimed to investigate changes in the spine system of soldiers after LCT at high altitudes and the change trend of the lumbar spine and surrounding soft tissues under different load conditions.Methods: Magnetic resonance imaging scans of the lumbar spines of nine soldiers from plateau troops were collected and processed. We used ImageJ and Surgimap software to analyze changes in the lumbar paraspinal muscles, intervertebral discs(IVDs), intervertebral foramina, and curvature. Furthermore, the multiple linear regression equation for spine injury owing to LCT at high altitudes was established as the mathematical prediction model using SPSS Statistics version 23.0 software.Results: In the paraspinal muscles, the cross-sectional area(CSA) increased significantly from(9126.4±691.6) mm~2 to(9862.7±456.4) mm~2, and the functional CSA(FCSA) increased significantly from(8089.6±707.7) mm~2 to(8747.9±426.2) mm~2 after LCT(P<0.05);however, the FCSA/CSA was not significantly different. Regarding IVD, the total lumbar spine showed a decreasing trend after LCT with a significant difference(P<0.05). Regarding the lumbar intervertebral foramen, the percentage of the effective intervertebral foraminal area of L3/4 significantly decreased from 91.6%±2.0% to 88.1%±2.9%(P<0.05). For curvature, the lumbosacral angle after LCT(32.4°±6.8°) was significantly higher(P<0.05) than that before LCT(26.6°±5.3°), while the lumbar lordosis angle increased significantly from(24.0°±7.1°) to(30.6°±7.4°)(P<0.05). The linear regression equation of the change rate, ΔFCSA%=–0.718+23.085×load weight, was successfully established as a prediction model of spinal injury after LCT at high altitudes.Conclusion: The spinal system encountered increased muscle volume, muscle congestion, tissue edema, IVD compression, decreased effective intervertebral foramen area, and increased lumbar curvature after LCT, which revealed important pathophysiological mechanisms of lumbar spinal disorders in soldiers following short-term and high-load weight training. The injury prediction model of the spinal system confirmed that a load weight <60% of soldiers' weight cannot cause acute pathological injury after short-term LCT, providing a reference supporting the formulation of the load weight standard for LCT.展开更多
Bone marrow mesenchymal stem cell(BMSC)osteogenic differentiation and osteoblast function play critical roles in bone formation,which is a highly regulated process.Long noncoding RNAs(lncRNAs)perform diverse functions...Bone marrow mesenchymal stem cell(BMSC)osteogenic differentiation and osteoblast function play critical roles in bone formation,which is a highly regulated process.Long noncoding RNAs(lncRNAs)perform diverse functions in a variety of biological processes,including BMSC osteogenic differentiation.Although several studies have reported that HOX transcript antisense RNA(HOTAIR)is involved in BMSC osteogenic differentiation,its effect on bone formation in vivo remains unclear.Here,by constructing transgenic mice with BMSC(Prx1-HOTAIR)-and osteoblast(Bglap-HOTAIR)-specific overexpression of HOTAIR,we found that Prx1-HOTAIR and Bglap-HOTAIR transgenic mice show different bone phenotypes in vivo.Specifically,Prx1-HOTAIR mice showed delayed bone formation,while Bglap-HOTAIR mice showed increased bone formation.HOTAIR inhibits BMSC osteogenic differentiation but promotes osteoblast function in vitro.Furthermore,we identified that HOTAIR is mainly located in the nucleus of BMSCs and in the cytoplasm of osteoblasts.HOTAIR displays a nucleocytoplasmic translocation pattern during BMSC osteogenic differentiation.We first identified that the RNA-binding protein human antigen R(HuR)is responsible for HOTAIR nucleocytoplasmic translocation.HOTAIR is essential for osteoblast function,and cytoplasmic HOTAIR binds to miR-214 and acts as a ceRNA to increase Atf4 protein levels and osteoblast function.BglapHOTAIR mice,but not Prx1-HOTAIR mice,showed alleviation of bone loss induced by unloading.This study reveals the importance of temporal and spatial regulation of HOTAIR in BMSC osteogenic differentiation and bone formation,which provides new insights into precise regulation as a target for bone loss.展开更多
It is important to calculate the reachable domain(RD)of the manned lunar mission to evaluate whether a lunar landing site could be reached by the spacecraft. In this paper, the RD of free return orbits is quickly eval...It is important to calculate the reachable domain(RD)of the manned lunar mission to evaluate whether a lunar landing site could be reached by the spacecraft. In this paper, the RD of free return orbits is quickly evaluated and calculated via the classification and regression neural networks. An efficient databasegeneration method is developed for obtaining eight types of free return orbits and then the RD is defined by the orbit’s inclination and right ascension of ascending node(RAAN) at the perilune. A classify neural network and a regression network are trained respectively. The former is built for classifying the type of the RD, and the latter is built for calculating the inclination and RAAN of the RD. The simulation results show that two neural networks are well trained. The classification model has an accuracy of more than 99% and the mean square error of the regression model is less than 0.01°on the test set. Moreover, a serial strategy is proposed to combine the two surrogate models and a recognition tool is built to evaluate whether a lunar site could be reached. The proposed deep learning method shows the superiority in computation efficiency compared with the traditional double two-body model.展开更多
Objective To study the effect of Simulated Microgravity and its Associated Mechanism on Pulmonary Circulation in Rats. Methods Rat tail-suspension model was used to simulate the physiological effects of microgravity a...Objective To study the effect of Simulated Microgravity and its Associated Mechanism on Pulmonary Circulation in Rats. Methods Rat tail-suspension model was used to simulate the physiological effects of microgravity and changes in pulmonary blood vessel morphology, pulmonary arterial and venous blood pressure, pulmonary vascular resistance, pulmonary vasomotoricity, as well as the regulation of pulmonary circulation by cytokines produced and released by the lung of rats were measured. Results The walls of pulmonary blood vessels of rats were thickened, and the pulmonary artery was reconstructed with increased pulmonary vascular resistance. The pulmonary blood vessels of rats became more prone to dilation as contractions increased. Rat epithelial Adrenomedulin gene transcription and protein expression were upregulated. The level of basic fibroblast growth Factor of rat was also elevated. Conclusion Findings from the present study on rats revealed that the microgravity can affect pulmonary blood vessel structure, pulmonary arterial pressure, and pulmonary blood vessel self-regulation and cytokine production.展开更多
The development of skeletal muscle is a highly regulated,multi-step process in which pluripotent mesodermal cells give rise to myoblasts that subsequently withdraw from the cell cycle and differentiate into myotubes a...The development of skeletal muscle is a highly regulated,multi-step process in which pluripotent mesodermal cells give rise to myoblasts that subsequently withdraw from the cell cycle and differentiate into myotubes as well as myofibers.The plasticity of myoblasts plays a critical role in maintaining skeletal muscle structure and function by myoblast activation,migration,adhesion,membrane reorganization,nuclear fusion,finally forming myotubes/myofibers.Our studies demonstrate that the local hypoxic microenvironment,a great diversity of regulatory factors such as IL-6 superfamily factors(IL-6,LIF,CNTF) and TGF-β1 could regulate the myoblast plasticity.The aim of this paper is to review the previous studies focused on the regulation of myoblast plasticity and its mechanism in our laboratory.Knowledge about the microenvironment or factors involved in regulating the myoblast plasticity will help develop the prevention and cure measures of skeletal muscle diseases.展开更多
Exposure to thermal environment is one of the main concerns for manned space exploration. By focusing on the works performed on thermoregulation at microgravity or simulated microgravity, we endeavored to review the i...Exposure to thermal environment is one of the main concerns for manned space exploration. By focusing on the works performed on thermoregulation at microgravity or simulated microgravity, we endeavored to review the investigation on space thermal environmental physiology. First of all, the application of medical requirements for the crew module design from normal thermal comfort to accidental thermal emergencies in a space craft will be addressed. Then, alterations in the autonomic and behavioral temperature regulation caused by the effect of weightlessness both in space flight and its simulation on the ground are also discussed. Furthermore, countermeasures like exercise training, simulated natural ventilation, encouraged drink, etc., in the protection of thermoregulation during space flight is presented. Finally, the challenge of space thermal environment physiology faced in the future is figured out.展开更多
In the past two years,space life sciences research in China is characterized by a tendency toward integration of scientific and engineering resources in preparing and implementing advanced space programs.In the field ...In the past two years,space life sciences research in China is characterized by a tendency toward integration of scientific and engineering resources in preparing and implementing advanced space programs.In the field of operational medicine,we carried out an international cooperated Head-Down Bed Rest(HDBR) experiment and investigated the effects of Chinese herbs compounds on astronaut's physiological functions.The effect of microgravity and its mechanisms were further studied from the level of physiology and biology.At the same time,state-level platform for ground and space experiment was established.展开更多
Swertisin contents in rat urine,feces and tissues were determined by reversed-phase high-performance liquid chromatography(RP-HPLC) method.Chromatographic separations were performed on a C18 column with acetonitrile-w...Swertisin contents in rat urine,feces and tissues were determined by reversed-phase high-performance liquid chromatography(RP-HPLC) method.Chromatographic separations were performed on a C18 column with acetonitrile-water(23:77,v/v) as the mobile phase.The calibration curves were linear over the ranges of 0.175-35.0μg/mL for rat urine,0.5-60.0μg/mL for rat feces,and 0.014 to 53.0μg/mL for all tissues.The inter-and intra-day precisions and accuracy for all measured samples were satisfactory.The fully validated method was applied for tissue distribution and excretion of swertisin in rat urine and bile after intravenous administration.The maximum level of swertisin was found in kidney,which reached 83.87± 6.36μg/g.In rat heart,swertisin was hardly detected under used experimental conditions.Swetisin level in liver,kidney,stomach,smooth muscle and skeletal muscle continued to decrease from 5 to 60min.Swertisin showed increasing tendency in intestine,spleen and testis tissues at scheduled time points.Detectable swertisin was found in brain and lung tissue.Totally 11.9% swertisin dose was cumulatively excreted from urine in 60h after intravenous administration.There was small amount of swertisin in rat feces and the cumulative excretion level reached 4.59% of intravenous dose in 60h.展开更多
Pulsed microwaves are widely used in radar, navigation, and communication. The average power density is low at narrow pulse widths or large pulse intervals, but pulsed microwaves at certain peak densities exert numero...Pulsed microwaves are widely used in radar, navigation, and communication. The average power density is low at narrow pulse widths or large pulse intervals, but pulsed microwaves at certain peak densities exert numerous biological effects, including auditory effects. The peak threshold values at which pulsed microwaves begin to exert auditory effects in humans at pulse widths of 425 MHz, 125-1, 000 μs;1, 245 MHz, 10-70 μs;2, 450 MHz, 1-32 μs;and 3, 000 MHz, 1-100 μs are 229-271 mW/cm2, 60-80 mW/cm2, 64 mW/cm2, and 5, 000 mW/cm2, respectively, whereas the threshold value of microwaves at 8.9 GHz is > 25 W/cm2[1]. Threshold values vary among studies because of the use of different microwave-exposure parameters (e.g., frequency, pulse width, repetitions per second). Therefore, the International Commission of Non-ionizing Radiation Protection (ICNIRP) employs a spherical model based on thermoelastic theory and biophysics dose calculation to deduce the peak limits of microwaves of different frequencies. For example, the peak limit for frequencies exceeding 10 MHz should not exceed 1000-fold higher than the reference level over 6 min. However, whether limits based on the auditory effect theory are sufficient to prevent adverse effects must be determined because the use of appliances that emit pulsed microwaves with very high incident peak powers is increasing.展开更多
With the continuing progress in space exploration,a new and perplexing condition related to spaceflight ocular syndrome has emerged in the past four decades.National Aeronautics and Space Administration(NASA) has name...With the continuing progress in space exploration,a new and perplexing condition related to spaceflight ocular syndrome has emerged in the past four decades.National Aeronautics and Space Administration(NASA) has named this condition "spaceflight-associated neuro-ocular syndrome"(SANS).This article gives an overview of the current research about SANS and traditional Chinese medicine(TCM) by analyzing the existing publications on Pub Med and CNKI and reports from NASA about SANS,summarizing the potential pathogenesis of SANS and physical interventions for treating SANS,and discussing the feasibility of treating SANS with TCM.Due to the unique characteristics of the space environment,it is infeasible to conduct large-scale human studies of SANS.SANS may be the result of the interaction of multiple factors,including inflammation and fluid displacement in the optic nerve sheath and cerebrospinal fluid.We should pay attention to SANS.Visual function is not only related to the health of astronauts but also closely related to space operations.TCM has antioxidative stress and antiapoptotic effects and is widely used for optic nerve diseases.TCM has great potential to prevent SANS.展开更多
As a key link in human-computer interaction,emotion recognition can enable robots to correctly perceive user emotions and provide dynamic and adjustable services according to the emotional needs of different users,whi...As a key link in human-computer interaction,emotion recognition can enable robots to correctly perceive user emotions and provide dynamic and adjustable services according to the emotional needs of different users,which is the key to improve the cognitive level of robot service.Emotion recognition based on facial expression and electrocardiogram has numerous industrial applications.First,three-dimensional convolutional neural network deep learning architecture is utilized to extract the spatial and temporal features from facial expression video data and electrocardiogram(ECG)data,and emotion classification is carried out.Then two modalities are fused in the data level and the decision level,respectively,and the emotion recognition results are then given.Finally,the emotion recognition results of single-modality and multi-modality are compared and analyzed.Through the comparative analysis of the experimental results of single-modality and multi-modality under the two fusion methods,it is concluded that the accuracy rate of multi-modal emotion recognition is greatly improved compared with that of single-modal emotion recognition,and decision-level fusion is easier to operate and more effective than data-level fusion.展开更多
Will exercise-induced cardiovascular workload be monitored by Electrocardiogram (ECG) waveform morphology? The discrimination ability of ECG morphology from 30 subjects was tested for distinguishing states between exe...Will exercise-induced cardiovascular workload be monitored by Electrocardiogram (ECG) waveform morphology? The discrimination ability of ECG morphology from 30 subjects was tested for distinguishing states between exercise and relaxation in terms of side lengths, lengths of high lines, angles, perimeters and areas of triangle QRS and triangle T. As a result, 4 characters from triangle QRS had significant differences (t test, p<0.05) for over 85% of subjects in distinguishing between exercise states and relaxation states, which were: ratio of QR side length to RS side length in triangle QRS, angle S and angle Q, as well as the ratio between them. Moreover, ratio of angle S to angle Q had significant differences (t test, p<0.05) for all subjects. In conclusion, triangle characters in ECG could be used to distinguish exercise states from relaxation states.展开更多
Flexible pressure sensors have attracted wide attention due to their applications to electronic skin,health monitoring,and human-machine interaction.However,the tradeoff between their high sensitivity and wide respons...Flexible pressure sensors have attracted wide attention due to their applications to electronic skin,health monitoring,and human-machine interaction.However,the tradeoff between their high sensitivity and wide response range remains a challenge.Inspired by human skin,we select commercial silicon carbide sandpaper as a template to fabricate carbon nanotube(CNT)/polydimethylsiloxane(PDMS)composite film with a hierarchical structured surface(h-CNT/PDMS)through solution blending and blade coating and then assemble the h-CNT/PDMS composite film with interdigitated electrodes and polyurethane(PU)scotch tape to obtain an h-CNT/PDMS-based flexible pressure sensor.Based on in-situ optical images and finite element analysis,the significant compressive contact effect between the hierarchical structured surface of h-CNT/PDMS and the interdigitated electrode leads to enhanced pressure sensitivity and a wider response range(0.1661 kPa^(-1),0.4574 kPa^(-1)and 0.0989 kPa^(-1)in the pressure range of 0–18 kPa,18–133 kPa and 133–300 kPa)compared with planar CNT/PDMS composite film(0.0066 kPa^(-1)in the pressure range of 0–240 kPa).The prepared pressure sensor displays rapid response/recovery time,excellent stability,durability,and stable response to different loading modes(bending and torsion).In addition,our pressure sensor can be utilized to accurately monitor and discriminate various stimuli ranging from human motions to pressure magnitude and spatial distribution.This study supplies important guidance for the fabrication of flexible pressure sensors with superior sensing performance in next-generation wearable electronic devices.展开更多
Serving the Stewart mechanism as a wheel-legged structure,the most outstanding superiority of the proposed wheel-legged hybrid robot(WLHR)is the active vibration isolation function during rolling on rugged terrain.How...Serving the Stewart mechanism as a wheel-legged structure,the most outstanding superiority of the proposed wheel-legged hybrid robot(WLHR)is the active vibration isolation function during rolling on rugged terrain.However,it is difficult to obtain its precise dynamic model,because of the nonlinearity and uncertainty of the heavy robot.This paper presents a dynamic control framework with a decentralized structure for single wheel-leg,position tracking based on model predictive control(MPC)and adaptive impedance module from inside to outside.Through the Newton-Euler dynamic model of the Stewart mechanism,the controller first creates a predictive model by combining Newton-Raphson iteration of forward kinematic and inverse kinematic calculation of Stewart.The actuating force naturally enables each strut to stretch and retract,thereby realizing six degrees-of-freedom(6-DOFs)position-tracking for Stewart wheel-leg.The adaptive impedance control in the outermost loop adjusts environmental impedance parameters by current position and force feedback of wheel-leg along Z-axis.This adjustment allows the robot to adequately control the desired support force tracking,isolating the robot body from vibration that is generated from unknown terrain.The availability of the proposed control methodology on a physical prototype is demonstrated by tracking a Bezier curve and active vibration isolation while the robot is rolling on decelerate strips.By comparing the proportional and integral(PI)and constant impedance controllers,better performance of the proposed algorithm was operated and evaluated through displacement and force sensors internally-installed in each cylinder,as well as an inertial measurement unit(IMU)mounted on the robot body.The proposed algorithm structure significantly enhances the control accuracy and vibration isolation capacity of parallel wheel-legged robot.展开更多
Kear Editor,Individuals in isolated,confined,and extreme environments,such as astronauts,researchers wintering over Antarctica,submarine soldiers,and participants in simulated isolation environment experiments,commonl...Kear Editor,Individuals in isolated,confined,and extreme environments,such as astronauts,researchers wintering over Antarctica,submarine soldiers,and participants in simulated isolation environment experiments,commonly report difficulty in focusing their attention[1,2].However,current experimental findings from studies conducted in such environments are insufficient to fully support these self-reports of reduced attention.Certain attention-demanding tasks such as simple reaction time(RT)tasks and dual tasks,including primary pursuit tracking and secondary RT,were not affected in space flight experiments[2,3].展开更多
基金supported by the Manned Spaceflight Program of China,the Advanced Space Medio-Engineering Research Project of China(2014SY54A0001)
文摘Sufficient sleep duration and good sleep quality are crucial to ensure normal physical and mental health, cognition and work performance for the common people, as well as astronauts. On-orbit sleep problem is very common among astronauts and has potential detrimental influences on the health of crewmembers and the safety of flight missions. Sleep in space is becoming a new medical research frontier. In this review we summarized on-orbit sleep problems of astronauts and six kinds of causes, and we presented the effects of lack of sleep on performance as well as mental and physical health, then we proposed seven kinds of countermeasures for sleep disturbance in spaceflight, including pharmacologic interventions, light treatment, crew selection and training, Traditional Chinese Medicine and so on. Furthermore, we discussed and oriented the prospect of researches on sleep in space.
基金supported by the National Basic Program of China (2011CB711000 and 2012CB947600)the National Natural Science Foundation of China (31171119, 31171010, 31171049, 31121061, 31271164)Open Fund from Key Laboratory for Space Biosciences & Biotechnology, Northwestern Polytechnical University (2013KF1501)
文摘The circadian clock and sleep are essential for human physiology and behavior; deregulation of circadian rhythms impairs health and performance. Circadian clocks and sleep evolved to adapt to Earth's environment, which is characterized by a 24-hour light–dark cycle. Changes in gravity load, lighting and work schedules during spaceflight missions can impact circadian clocks and disrupt sleep, in turn jeopardizing the mood, cognition and performance of orbiting astronauts. In this review, we summarize our understanding of both the influence of the space environment on the circadian timing system and sleep and the impact of these changes on astronaut physiology and performance.
文摘In 2021,China Space Station(CSS)was assembled and constructed in-orbit,which provided a broad space platform for space medicine and space life sciences research.Space medicine focuses on the systematic risks that restrict long-term manned spaceflight.It carries out systematic research on the impact and countermeasure technology of long-term weightlessness on astronauts’health,space radiation on astronauts’health,behavior and ability,advanced on-orbit monitoring and medical disposal technology,and traditional space medical application technology by the space medicine experiment platform on human body and cell.It has accumulated valuable data on space environmental effects and human factors research,established a“human system risk”research system,obtained new knowledge and discoveries of space medicine,and explored countermeasure technologies of new characteristics.Moreover,a series of achievements have been made in the basic research on the mechanism of the special space environmental effect,which provides a solid foundation for the implementation of space missions.
基金supported by the National Key Research and Development Program of China (2018YFB1307603)the National Natural Science Foundation of China (8174100706)。
文摘Background: Low back pain is the most common spinal disorder among soldiers, and load carriage training(LCT) is considered the main cause. We aimed to investigate changes in the spine system of soldiers after LCT at high altitudes and the change trend of the lumbar spine and surrounding soft tissues under different load conditions.Methods: Magnetic resonance imaging scans of the lumbar spines of nine soldiers from plateau troops were collected and processed. We used ImageJ and Surgimap software to analyze changes in the lumbar paraspinal muscles, intervertebral discs(IVDs), intervertebral foramina, and curvature. Furthermore, the multiple linear regression equation for spine injury owing to LCT at high altitudes was established as the mathematical prediction model using SPSS Statistics version 23.0 software.Results: In the paraspinal muscles, the cross-sectional area(CSA) increased significantly from(9126.4±691.6) mm~2 to(9862.7±456.4) mm~2, and the functional CSA(FCSA) increased significantly from(8089.6±707.7) mm~2 to(8747.9±426.2) mm~2 after LCT(P<0.05);however, the FCSA/CSA was not significantly different. Regarding IVD, the total lumbar spine showed a decreasing trend after LCT with a significant difference(P<0.05). Regarding the lumbar intervertebral foramen, the percentage of the effective intervertebral foraminal area of L3/4 significantly decreased from 91.6%±2.0% to 88.1%±2.9%(P<0.05). For curvature, the lumbosacral angle after LCT(32.4°±6.8°) was significantly higher(P<0.05) than that before LCT(26.6°±5.3°), while the lumbar lordosis angle increased significantly from(24.0°±7.1°) to(30.6°±7.4°)(P<0.05). The linear regression equation of the change rate, ΔFCSA%=–0.718+23.085×load weight, was successfully established as a prediction model of spinal injury after LCT at high altitudes.Conclusion: The spinal system encountered increased muscle volume, muscle congestion, tissue edema, IVD compression, decreased effective intervertebral foramen area, and increased lumbar curvature after LCT, which revealed important pathophysiological mechanisms of lumbar spinal disorders in soldiers following short-term and high-load weight training. The injury prediction model of the spinal system confirmed that a load weight <60% of soldiers' weight cannot cause acute pathological injury after short-term LCT, providing a reference supporting the formulation of the load weight standard for LCT.
基金supported by the National Natural Science Foundation of China Project(No.82072108,82192880,82192882,81830061,91740114 and 32000879)the Space Medical Experiment Project of China Manned Space Program(HYZHXM01006)National Key Laboratory of Space Medicine,China Astronaut Research and Training Center(SMFA22Q02)。
文摘Bone marrow mesenchymal stem cell(BMSC)osteogenic differentiation and osteoblast function play critical roles in bone formation,which is a highly regulated process.Long noncoding RNAs(lncRNAs)perform diverse functions in a variety of biological processes,including BMSC osteogenic differentiation.Although several studies have reported that HOX transcript antisense RNA(HOTAIR)is involved in BMSC osteogenic differentiation,its effect on bone formation in vivo remains unclear.Here,by constructing transgenic mice with BMSC(Prx1-HOTAIR)-and osteoblast(Bglap-HOTAIR)-specific overexpression of HOTAIR,we found that Prx1-HOTAIR and Bglap-HOTAIR transgenic mice show different bone phenotypes in vivo.Specifically,Prx1-HOTAIR mice showed delayed bone formation,while Bglap-HOTAIR mice showed increased bone formation.HOTAIR inhibits BMSC osteogenic differentiation but promotes osteoblast function in vitro.Furthermore,we identified that HOTAIR is mainly located in the nucleus of BMSCs and in the cytoplasm of osteoblasts.HOTAIR displays a nucleocytoplasmic translocation pattern during BMSC osteogenic differentiation.We first identified that the RNA-binding protein human antigen R(HuR)is responsible for HOTAIR nucleocytoplasmic translocation.HOTAIR is essential for osteoblast function,and cytoplasmic HOTAIR binds to miR-214 and acts as a ceRNA to increase Atf4 protein levels and osteoblast function.BglapHOTAIR mice,but not Prx1-HOTAIR mice,showed alleviation of bone loss induced by unloading.This study reveals the importance of temporal and spatial regulation of HOTAIR in BMSC osteogenic differentiation and bone formation,which provides new insights into precise regulation as a target for bone loss.
基金supported by the National Natural Science Foundation of China (12072365)the Natural Science Foundation of Hunan Province of China (2020JJ4657)。
文摘It is important to calculate the reachable domain(RD)of the manned lunar mission to evaluate whether a lunar landing site could be reached by the spacecraft. In this paper, the RD of free return orbits is quickly evaluated and calculated via the classification and regression neural networks. An efficient databasegeneration method is developed for obtaining eight types of free return orbits and then the RD is defined by the orbit’s inclination and right ascension of ascending node(RAAN) at the perilune. A classify neural network and a regression network are trained respectively. The former is built for classifying the type of the RD, and the latter is built for calculating the inclination and RAAN of the RD. The simulation results show that two neural networks are well trained. The classification model has an accuracy of more than 99% and the mean square error of the regression model is less than 0.01°on the test set. Moreover, a serial strategy is proposed to combine the two surrogate models and a recognition tool is built to evaluate whether a lunar site could be reached. The proposed deep learning method shows the superiority in computation efficiency compared with the traditional double two-body model.
基金supported by the Defense Medical Fund of China, 06Z048China Advanced Space Medico-engineering Research Project, 2011SY5406018 and SJ200801+2 种基金The State Key Laboratory of Space Medicine FundamentalsApplication of China Astronaut Research and Training CenterSMFA09A02, SMFA11A01 and SMFA12K04
文摘Objective To study the effect of Simulated Microgravity and its Associated Mechanism on Pulmonary Circulation in Rats. Methods Rat tail-suspension model was used to simulate the physiological effects of microgravity and changes in pulmonary blood vessel morphology, pulmonary arterial and venous blood pressure, pulmonary vascular resistance, pulmonary vasomotoricity, as well as the regulation of pulmonary circulation by cytokines produced and released by the lung of rats were measured. Results The walls of pulmonary blood vessels of rats were thickened, and the pulmonary artery was reconstructed with increased pulmonary vascular resistance. The pulmonary blood vessels of rats became more prone to dilation as contractions increased. Rat epithelial Adrenomedulin gene transcription and protein expression were upregulated. The level of basic fibroblast growth Factor of rat was also elevated. Conclusion Findings from the present study on rats revealed that the microgravity can affect pulmonary blood vessel structure, pulmonary arterial pressure, and pulmonary blood vessel self-regulation and cytokine production.
基金This research was supported in part by National Natural Science Foundation of China，supported by Research Funds of China Space Medical Engineering，supported by State Key Laboratory of Space Medicine Fundamentals and Applications, China Astronaut Research and Training Centre
基金supported by grants from National Basic Research Program of China(2011CB711000)Natural Sciences Foundation of China(31171144+1 种基金81272177)State Key Laboratory Grant of Space Medicine Fundamentals and Application(SM-FA09A01)
文摘The development of skeletal muscle is a highly regulated,multi-step process in which pluripotent mesodermal cells give rise to myoblasts that subsequently withdraw from the cell cycle and differentiate into myotubes as well as myofibers.The plasticity of myoblasts plays a critical role in maintaining skeletal muscle structure and function by myoblast activation,migration,adhesion,membrane reorganization,nuclear fusion,finally forming myotubes/myofibers.Our studies demonstrate that the local hypoxic microenvironment,a great diversity of regulatory factors such as IL-6 superfamily factors(IL-6,LIF,CNTF) and TGF-β1 could regulate the myoblast plasticity.The aim of this paper is to review the previous studies focused on the regulation of myoblast plasticity and its mechanism in our laboratory.Knowledge about the microenvironment or factors involved in regulating the myoblast plasticity will help develop the prevention and cure measures of skeletal muscle diseases.
基金supported by the National Natural Science Foundation of China(50838003)the China Manned Space flight Project
文摘Exposure to thermal environment is one of the main concerns for manned space exploration. By focusing on the works performed on thermoregulation at microgravity or simulated microgravity, we endeavored to review the investigation on space thermal environmental physiology. First of all, the application of medical requirements for the crew module design from normal thermal comfort to accidental thermal emergencies in a space craft will be addressed. Then, alterations in the autonomic and behavioral temperature regulation caused by the effect of weightlessness both in space flight and its simulation on the ground are also discussed. Furthermore, countermeasures like exercise training, simulated natural ventilation, encouraged drink, etc., in the protection of thermoregulation during space flight is presented. Finally, the challenge of space thermal environment physiology faced in the future is figured out.
文摘In the past two years,space life sciences research in China is characterized by a tendency toward integration of scientific and engineering resources in preparing and implementing advanced space programs.In the field of operational medicine,we carried out an international cooperated Head-Down Bed Rest(HDBR) experiment and investigated the effects of Chinese herbs compounds on astronaut's physiological functions.The effect of microgravity and its mechanisms were further studied from the level of physiology and biology.At the same time,state-level platform for ground and space experiment was established.
基金Supported by the Excellent Young Scholars Research Foundation of Beijing Institute of Technology(2007Y0612)
文摘Swertisin contents in rat urine,feces and tissues were determined by reversed-phase high-performance liquid chromatography(RP-HPLC) method.Chromatographic separations were performed on a C18 column with acetonitrile-water(23:77,v/v) as the mobile phase.The calibration curves were linear over the ranges of 0.175-35.0μg/mL for rat urine,0.5-60.0μg/mL for rat feces,and 0.014 to 53.0μg/mL for all tissues.The inter-and intra-day precisions and accuracy for all measured samples were satisfactory.The fully validated method was applied for tissue distribution and excretion of swertisin in rat urine and bile after intravenous administration.The maximum level of swertisin was found in kidney,which reached 83.87± 6.36μg/g.In rat heart,swertisin was hardly detected under used experimental conditions.Swetisin level in liver,kidney,stomach,smooth muscle and skeletal muscle continued to decrease from 5 to 60min.Swertisin showed increasing tendency in intestine,spleen and testis tissues at scheduled time points.Detectable swertisin was found in brain and lung tissue.Totally 11.9% swertisin dose was cumulatively excreted from urine in 60h after intravenous administration.There was small amount of swertisin in rat feces and the cumulative excretion level reached 4.59% of intravenous dose in 60h.
基金supported by the Foundation of Astronaut Research and Training Center of China [No.SMFA14B06 and No.14ZS017]
文摘Pulsed microwaves are widely used in radar, navigation, and communication. The average power density is low at narrow pulse widths or large pulse intervals, but pulsed microwaves at certain peak densities exert numerous biological effects, including auditory effects. The peak threshold values at which pulsed microwaves begin to exert auditory effects in humans at pulse widths of 425 MHz, 125-1, 000 μs;1, 245 MHz, 10-70 μs;2, 450 MHz, 1-32 μs;and 3, 000 MHz, 1-100 μs are 229-271 mW/cm2, 60-80 mW/cm2, 64 mW/cm2, and 5, 000 mW/cm2, respectively, whereas the threshold value of microwaves at 8.9 GHz is > 25 W/cm2[1]. Threshold values vary among studies because of the use of different microwave-exposure parameters (e.g., frequency, pulse width, repetitions per second). Therefore, the International Commission of Non-ionizing Radiation Protection (ICNIRP) employs a spherical model based on thermoelastic theory and biophysics dose calculation to deduce the peak limits of microwaves of different frequencies. For example, the peak limit for frequencies exceeding 10 MHz should not exceed 1000-fold higher than the reference level over 6 min. However, whether limits based on the auditory effect theory are sufficient to prevent adverse effects must be determined because the use of appliances that emit pulsed microwaves with very high incident peak powers is increasing.
基金Supported by China HT Medical Engineering Pre-research Project (No.2017SY54A0302)Open Funding Project of National Key Laboratory of Human Factors Engineering (No.SYFD180051808K)。
文摘With the continuing progress in space exploration,a new and perplexing condition related to spaceflight ocular syndrome has emerged in the past four decades.National Aeronautics and Space Administration(NASA) has named this condition "spaceflight-associated neuro-ocular syndrome"(SANS).This article gives an overview of the current research about SANS and traditional Chinese medicine(TCM) by analyzing the existing publications on Pub Med and CNKI and reports from NASA about SANS,summarizing the potential pathogenesis of SANS and physical interventions for treating SANS,and discussing the feasibility of treating SANS with TCM.Due to the unique characteristics of the space environment,it is infeasible to conduct large-scale human studies of SANS.SANS may be the result of the interaction of multiple factors,including inflammation and fluid displacement in the optic nerve sheath and cerebrospinal fluid.We should pay attention to SANS.Visual function is not only related to the health of astronauts but also closely related to space operations.TCM has antioxidative stress and antiapoptotic effects and is widely used for optic nerve diseases.TCM has great potential to prevent SANS.
基金supported by the Open Funding Project of National Key Laboratory of Human Factors Engineering(Grant NO.6142222190309)。
文摘As a key link in human-computer interaction,emotion recognition can enable robots to correctly perceive user emotions and provide dynamic and adjustable services according to the emotional needs of different users,which is the key to improve the cognitive level of robot service.Emotion recognition based on facial expression and electrocardiogram has numerous industrial applications.First,three-dimensional convolutional neural network deep learning architecture is utilized to extract the spatial and temporal features from facial expression video data and electrocardiogram(ECG)data,and emotion classification is carried out.Then two modalities are fused in the data level and the decision level,respectively,and the emotion recognition results are then given.Finally,the emotion recognition results of single-modality and multi-modality are compared and analyzed.Through the comparative analysis of the experimental results of single-modality and multi-modality under the two fusion methods,it is concluded that the accuracy rate of multi-modal emotion recognition is greatly improved compared with that of single-modal emotion recognition,and decision-level fusion is easier to operate and more effective than data-level fusion.
文摘Will exercise-induced cardiovascular workload be monitored by Electrocardiogram (ECG) waveform morphology? The discrimination ability of ECG morphology from 30 subjects was tested for distinguishing states between exercise and relaxation in terms of side lengths, lengths of high lines, angles, perimeters and areas of triangle QRS and triangle T. As a result, 4 characters from triangle QRS had significant differences (t test, p<0.05) for over 85% of subjects in distinguishing between exercise states and relaxation states, which were: ratio of QR side length to RS side length in triangle QRS, angle S and angle Q, as well as the ratio between them. Moreover, ratio of angle S to angle Q had significant differences (t test, p<0.05) for all subjects. In conclusion, triangle characters in ECG could be used to distinguish exercise states from relaxation states.
基金supported by the National Natural Science Foundation of China(NO:51803191,12072325,52103100)the National Key R&D Program of China(2019YFA0706802)+1 种基金the 111 project(D18023)the Key Scientific and Technological Project of Henan Province(202102210038).
文摘Flexible pressure sensors have attracted wide attention due to their applications to electronic skin,health monitoring,and human-machine interaction.However,the tradeoff between their high sensitivity and wide response range remains a challenge.Inspired by human skin,we select commercial silicon carbide sandpaper as a template to fabricate carbon nanotube(CNT)/polydimethylsiloxane(PDMS)composite film with a hierarchical structured surface(h-CNT/PDMS)through solution blending and blade coating and then assemble the h-CNT/PDMS composite film with interdigitated electrodes and polyurethane(PU)scotch tape to obtain an h-CNT/PDMS-based flexible pressure sensor.Based on in-situ optical images and finite element analysis,the significant compressive contact effect between the hierarchical structured surface of h-CNT/PDMS and the interdigitated electrode leads to enhanced pressure sensitivity and a wider response range(0.1661 kPa^(-1),0.4574 kPa^(-1)and 0.0989 kPa^(-1)in the pressure range of 0–18 kPa,18–133 kPa and 133–300 kPa)compared with planar CNT/PDMS composite film(0.0066 kPa^(-1)in the pressure range of 0–240 kPa).The prepared pressure sensor displays rapid response/recovery time,excellent stability,durability,and stable response to different loading modes(bending and torsion).In addition,our pressure sensor can be utilized to accurately monitor and discriminate various stimuli ranging from human motions to pressure magnitude and spatial distribution.This study supplies important guidance for the fabrication of flexible pressure sensors with superior sensing performance in next-generation wearable electronic devices.
基金Supported by National Natural Science Foundation of China(Grant No.61773060).
文摘Serving the Stewart mechanism as a wheel-legged structure,the most outstanding superiority of the proposed wheel-legged hybrid robot(WLHR)is the active vibration isolation function during rolling on rugged terrain.However,it is difficult to obtain its precise dynamic model,because of the nonlinearity and uncertainty of the heavy robot.This paper presents a dynamic control framework with a decentralized structure for single wheel-leg,position tracking based on model predictive control(MPC)and adaptive impedance module from inside to outside.Through the Newton-Euler dynamic model of the Stewart mechanism,the controller first creates a predictive model by combining Newton-Raphson iteration of forward kinematic and inverse kinematic calculation of Stewart.The actuating force naturally enables each strut to stretch and retract,thereby realizing six degrees-of-freedom(6-DOFs)position-tracking for Stewart wheel-leg.The adaptive impedance control in the outermost loop adjusts environmental impedance parameters by current position and force feedback of wheel-leg along Z-axis.This adjustment allows the robot to adequately control the desired support force tracking,isolating the robot body from vibration that is generated from unknown terrain.The availability of the proposed control methodology on a physical prototype is demonstrated by tracking a Bezier curve and active vibration isolation while the robot is rolling on decelerate strips.By comparing the proportional and integral(PI)and constant impedance controllers,better performance of the proposed algorithm was operated and evaluated through displacement and force sensors internally-installed in each cylinder,as well as an inertial measurement unit(IMU)mounted on the robot body.The proposed algorithm structure significantly enhances the control accuracy and vibration isolation capacity of parallel wheel-legged robot.
文摘Kear Editor,Individuals in isolated,confined,and extreme environments,such as astronauts,researchers wintering over Antarctica,submarine soldiers,and participants in simulated isolation environment experiments,commonly report difficulty in focusing their attention[1,2].However,current experimental findings from studies conducted in such environments are insufficient to fully support these self-reports of reduced attention.Certain attention-demanding tasks such as simple reaction time(RT)tasks and dual tasks,including primary pursuit tracking and secondary RT,were not affected in space flight experiments[2,3].
