Specialized pro-resolving lipid mediators including maresin 1 mediate resolution but the levels of these are reduced in Alzheimer's disease brain, suggesting that they constitute a novel target for the treatment o...Specialized pro-resolving lipid mediators including maresin 1 mediate resolution but the levels of these are reduced in Alzheimer's disease brain, suggesting that they constitute a novel target for the treatment of Alzheimer's disease to prevent/stop inflammation and combat disease pathology. Therefore, it is important to clarify whether they counteract the expression of genes and proteins induced by amyloid-β. With this objective, we analyzed the relevance of human monocyte–derived microglia for in vitro modeling of neuroinflammation and its resolution in the context of Alzheimer's disease and investigated the pro-resolving bioactivity of maresin 1 on amyloid-β42–induced Alzheimer's disease–like inflammation. Analysis of RNA-sequencing data and secreted proteins in supernatants from the monocyte-derived microglia showed that the monocyte-derived microglia resembled Alzheimer's disease–like neuroinflammation in human brain microglia after incubation with amyloid-β42. Maresin 1 restored homeostasis by down-regulating inflammatory pathway related gene expression induced by amyloid-β42 in monocyte-derived microglia, protection of maresin 1 against the effects of amyloid-β42 is mediated by a re-balancing of inflammatory transcriptional networks in which modulation of gene transcription in the nuclear factor-kappa B pathway plays a major part. We pinpointed molecular targets that are associated with both neuroinflammation in Alzheimer's disease and therapeutic targets by maresin 1. In conclusion, monocyte-derived microglia represent a relevant in vitro microglial model for studies on Alzheimer's disease-like inflammation and drug response for individual patients. Maresin 1 ameliorates amyloid-β42–induced changes in several genes of importance in Alzheimer's disease, highlighting its potential as a therapeutic target for Alzheimer's disease.展开更多
Light-absorbing impurities on glaciers are important factors that influence glacial surface albedo and accelerate glacier melt. In this study, the quantity of light-absorbing impurities on Keqikaer Glacier in western ...Light-absorbing impurities on glaciers are important factors that influence glacial surface albedo and accelerate glacier melt. In this study, the quantity of light-absorbing impurities on Keqikaer Glacier in western Tien Shan, Central Asia, was measured. We found that the average concentrations of black carbon was 2,180 ng/g, with a range from 250 ng/g to more than 10,000 ng/g. The average concentrations of organic carbon and mineral dust were 1,738 ng/g and 194 μg/g, respectively. Based on simulations performed with the Snow Ice Aerosol Radiative model simulations, black carbon and dust are responsible for approximately 64% and 9%, respectively, of the albedo reduction, and are associated with instantaneous radiative forcing of 323.18 W/m2(ranging from 142.16 to 619.25 W/m2) and 24.05 W/m2(ranging from 0.15 to69.77 W/m2), respectively. For different scenarios, the albedo and radiative forcing effect of black carbon is considerably greater than that of dust. The estimated radiative forcing at Keqikaer Glacier is higher than most similar values estimated by previous studies on the Tibetan Plateau, perhaps as a result of black carbon enrichment by melt scavenging. Light-absorbing impurities deposited on Keqikaer Glacier appear to mainly originate from central Asia, Siberia, western China(including the Taklimakan Desert) and parts of South Asia in summer, and from the Middle East and Central Asia in winter.A footprint analysis indicates that a large fraction(>60%) of the black carbon contributions on Keqikaer Glacier comes from anthropogenic sources. These results provide a scientific basis for regional mitigation efforts to reduce black carbon.展开更多
In southern China,the eucalyptus plantation industry has been severely restricted by government policy over concerns on negative environmental impacts.In its place,large-scale plantations of high-value tropical tree s...In southern China,the eucalyptus plantation industry has been severely restricted by government policy over concerns on negative environmental impacts.In its place,large-scale plantations of high-value tropical tree species such as nitrogen-fixing Dalbergia odorifera and hemiparasite Santalum album have been widely cultivated including in mixed-species plantations.However,despite their poor growth,little information is available on suitable silvicultural practices of these plantations.Therefore,we subjected an 8-year-old mixed stand of D.odorifera and S.album to weeding,fertilization,weeding+fertilization,or no(CK)treatments and measured soil microbial biomass,respiration,nutrients,nitrogen mineralization and leaching and tree growth and litter production.Weeding and fertilization decreased microbial biomass but increased soil respiration,inhibited mineralization,had not effect on leaching of soil nitrogen,and improved the nutrient status of plantation soil.All practices improved the growth of D.odorifera.In the mixed plantation,fertilization increased litter production and nutrient content,but weeding and weeding+fertilization decreased growth of S.album and litter production in mixed plantation because weeding decreased the number of S.album haustoria in underground plant roots.In conclusion,fertilization is recommended;however,weeding-related practices are inappropriate for D.odorifera and S.album mixed plantations.These conclusions have important implications for managing other parasite or mixed-species plantations.展开更多
This article proposes a deep neural network(DNN)-based direct-path relative transfer function(DP-RTF)enhancement method for robust direction of arrival(DOA)estimation in noisy and reverberant environments.The DP-RTF r...This article proposes a deep neural network(DNN)-based direct-path relative transfer function(DP-RTF)enhancement method for robust direction of arrival(DOA)estimation in noisy and reverberant environments.The DP-RTF refers to the ratio between the directpath acoustic transfer functions of the two microphone channels.First,the complex-value DP-RTF is decomposed into the inter-channel intensity difference,and sinusoidal functions of the inter-channel phase difference in the time-frequency domain.Then,the decomposed DP-RTF features from a series of temporal context frames are utilized to train a DNN model,which maps the DP-RTF features contaminated by noise and reverberation to the clean ones,and meanwhile provides a time-frequency(TF)weight to indicate the reliability of the mapping.The DP-RTF enhancement network can help to enhance the DP-RTF against noise and reverberation.Finally,the DOA of a sound source can be estimated by integrating the weighted matching between the enhanced DP-RTF features and the DP-RTF templates.Experimental results on simulated data show the superiority of the proposed DP-RTF enhancement network for estimating the DOA of the sound source in the environments with various levels of noise and reverberation.展开更多
[Objectives] To study the protection of compatibility of Saikosapon d and Baicalin on carbon tetrachloride( CCl_4) injured L-02 cells. [Methods] Normal human hepatocyte cell line L-02 cells were cultured in vitro,and ...[Objectives] To study the protection of compatibility of Saikosapon d and Baicalin on carbon tetrachloride( CCl_4) injured L-02 cells. [Methods] Normal human hepatocyte cell line L-02 cells were cultured in vitro,and CCl_4 was used to induce hepatocellular injury. Interventions were carried out with Saikosaponin d and Baicalin at different dosage. The proliferation of L-02 cells in each group was determined by methylthiazolyl tetrazolium( MTT) assay; the levels of AST and ALT in the culture supernatants were detected by enzyme-linked immunosorbent assay( ELISA); the expressions of TLR4 and NFκBp65 proteins in each group were determined by immunohistochemistry.[Results] In the CCl_4 injured group,the proliferation of L-02 cells was significantly declined,the levels of AST and ALT in cell culture medium were significantly increased,and the expressions of TLR4 and NFκBp65 in L-02 cells were increased; after the intervention of Saikosaponin d and Baicalin,1. 75 μg/mL group and 1. 5 μg/mL group had an effect of promoting the proliferation of L-02 cells and could reduce the levels of AST and ALT in the cell culture medium,and TLR4 and NFκBp65 proteins in L-02 cells also had a certain inhibitory effect. [Conclusions] The compatibility of Saikosapon d and Baicalin has a certain protective effect on CCl_4 injured L-02 cells. The protection mechanism may be related with its down-regulating TLR4-NFκB signaling pathway and reducing the inflammation.展开更多
Based on the existing literature,this paper analyzed and explored the factors that affect the efficiency of resource allocation,and evaluated the current situation of resource allocation in various fields.It is found ...Based on the existing literature,this paper analyzed and explored the factors that affect the efficiency of resource allocation,and evaluated the current situation of resource allocation in various fields.It is found that with the emergence of the new pattern of China’s economic development,the economic growth rate has slowed down,and the method of large-scale production driving economic growth is no longer applicable to the current economic situation.Nowadays,when structural transformation and upgrading have entered a new stage,to achieve the optimization of resource allocation efficiency,it is necessary to start from three aspects:improving information transparency,upgrading industrial structure,and planning government intervention.Through the adaptation analysis of blockchain technology and the existing problems in optimizing resource allocation efficiency,it explored the feasibility of blockchain technology to optimize resource allocation efficiency,and promote economical,efficient and high-quality development.展开更多
With the rapid development of Internet technology,the importance of blockchain technology has become increasingly prominent.Faced with this situation,extensive research has been carried out at home and abroad.Through ...With the rapid development of Internet technology,the importance of blockchain technology has become increasingly prominent.Faced with this situation,extensive research has been carried out at home and abroad.Through the analysis of relevant literature on blockchain in recent years,it is found that there are many research results of blockchain technology in medical care,finance,education,etc.,but its application in the field of resource allocation efficiency is rare.From the existing studies on the influencing factors of resource allocation efficiency in China,it is found that there are significant differences in resource allocation efficiency between China and some developed countries or between various provinces and cities of China.展开更多
Little is known about C-N-P stoichiometries and content in teak(Tectona grandis)plantations in South China,which are mostly sited on hilly areas with lateritic soil,and the effect of slope position on the accumulation...Little is known about C-N-P stoichiometries and content in teak(Tectona grandis)plantations in South China,which are mostly sited on hilly areas with lateritic soil,and the effect of slope position on the accumulation of these elements in trees and rhizosphere soils.Here we analyzed the C,N,P content and stoichiometry in leaves,fine roots and rhizosphere soils of trees on the upper and lower slopes of a 12-year-old teak plantation.The Kraft classification system of tree status was used to sample dominant,subdominant and mean trees at each slope position.The results showed that the C,N and P contents in leaves were higher than in fine roots and rhizosphere soils.The lowest C/N,C/P and N/P ratios were found in rhizosphere soils,and the C/N and C/P ratios in fine roots were higher than in leaves.Nutrient accumulation in leaves,fine roots and rhizosphere soils were significantly influenced by slope position and tree class with their interaction mainly showing a greater effect on rhizosphere soils.Leaf C content and C/N ratio,fine root C and P contents,and C/N and C/P ratios all increased distinctly with declining slope position.The contents of organic matter(SOM),ammonium(NH4+-N),nitrate-nitrogen(NO3--N)and available potassium(AK)in rhizosphere soils were mainly enriched on upper slopes,but exchange calcium(ECa),available phosphorus(AP),and pH were relatively lower.Variations in the C,N and P stoichiometries in trees were mainly attributed to the differences in rhizosphere soil properties.N and P contents showed significant positive linear relationships between leaf and rhizosphere soil,and C content negative linear correlation among leaves,fine roots and rhizosphere soils.Chemical properties of rhizosphere soils,particularly C/N and NH4+-N,had significant effects on the leaf nutrients in trees on the upper slope.Correspondingly,rhizosphere soil properties mainly influenced fine root nutrients on the lower slope,and soil AK was the major influencing factor.Overall,these results offer new insights for the sustainability and management of teak plantations in hilly areas.展开更多
As an important component of carbonaceous matters,dissolved organic carbon(DOC)can absorb and scatter the solar radiation at ultraviolet and blue wavelengths.The wet deposition process has great impact on the con-cent...As an important component of carbonaceous matters,dissolved organic carbon(DOC)can absorb and scatter the solar radiation at ultraviolet and blue wavelengths.The wet deposition process has great impact on the con-centration and light absorption ability of precipitation DOC,affecting the climatic effect caused by DOC in the atmosphere.In this study,light absorption and fluorescence characteristics of precipitation DOC was investigated in the central Tibetan Plateau(TP).The results showed that the mean DOC concentration and mass absorption cross-section measured at 365 nm(MAC_(365)) in Tanggula(TGL)station were 0.59±0.42 mg/L and 0.37±0.19 m^(2)/g,respectively,while both values showed much higher volatilities than those of aerosols.DOC concentrations had significant negative correlation with the precipitation amount,while MAC_(365) values increase with the precipitation amount in TGL station.Therefore,DOC with high light-absorbing ability was preferred to be retained in the atmosphere during wet deposition.In this study,precipitation DOC contained three fluorescent components(one humic-like component and two tyrosine-like components)mainly from local biomass burning sources.DOC concentration showed a negative relationship with MAC_(365) value in TGL station.The wet deposition of DOC with low light-absorbing ability can reduce the strong negative radiative forcing caused by secondary organic aerosol due to high proportion of DOC in secondary organic carbon.Similar phenomenon was also found in Nam Co,Lulang and Everest stations of previous study,which may have a potential impact on radiative forcing in the atmosphere of TP.展开更多
Moving humans,agents,and subjects bring many challenges to robot self‐localisation and environment perception.To adapt to dynamic environments,SLAM researchers typically apply several deep learning image segmentation...Moving humans,agents,and subjects bring many challenges to robot self‐localisation and environment perception.To adapt to dynamic environments,SLAM researchers typically apply several deep learning image segmentation models to eliminate these moving obstacles.However,these moving obstacle segmentation methods cost too much computation resource for the onboard processing of mobile robots.In the current industrial environment,mobile robot collaboration scenario,the noise of mobile robots could be easily found by on‐board audio‐sensing processors and the direction of sound sources can be effectively acquired by sound source estimation algorithms,but the distance estimation of sound sources is difficult.However,in the field of visual perception,the 3D structure information of the scene is relatively easy to obtain,but the recognition and segmentation of moving objects is more difficult.To address these problems,a novel vision‐audio fusion method that combines sound source localisation methods with a visual SLAM scheme is proposed,thereby eliminating the effect of dynamic obstacles on multi‐agent systems.Several heterogeneous robots experiments in different dynamic scenes indicate very stable self‐localisation and environment reconstruction performance of our method.展开更多
The control of the pseudospin of sound wave has attracted increasing attention in recent years.Utilizing the finite-size effect of topological acoustics,we successfully construct an H-shaped acoustic topological pseud...The control of the pseudospin of sound wave has attracted increasing attention in recent years.Utilizing the finite-size effect of topological acoustics,we successfully construct an H-shaped acoustic topological pseudospin switcher that sound wave energy can be easily switched through different passages.The interesting phenomenon of pseudospin flipping is numerically and experimentally demonstrated.A quantitative interference theory is proposed that the constructive and destructive interference of pseudospin states leads to pseudospin flipping and preserving in multiple frequencies.We verify the key parameters of the design,including the length of the passage and its interface state dispersion,and the theory can be extended to other topology acoustics and photonics systems.Moreover,the tunable topological sonic crystal we use provides adjustable convenience to pseudospin switcher design.The pseudospin switching behavior offers an efficient method to control the acoustic topological edge state transport,which has great potential in versatile applications,such as integrated acoustics,acoustic security,and information processing.展开更多
Astrocytes are intimately involved in the formation and development of retinal vessels. Astrocyte dysfunction is a major cause of blood-retinal barrier injury and other retinal vascular diseases. In this study, the de...Astrocytes are intimately involved in the formation and development of retinal vessels. Astrocyte dysfunction is a major cause of blood-retinal barrier injury and other retinal vascular diseases. In this study, the development of the retinal vascular system and the formation of the blood-ret-inal barrier in mice were investigated using immunolfuorescence staining, gelatin-ink perfusion, and transmission electron microscopy. The results showed that the retinal vascular system of mice develops from the optic disc after birth, and radiates out gradually to cover the entire retina, taking the papilla optica as the center. First, the superifcial vasculature is formed on the inner retinal layer;then, the vasculature extends into the inner and outer edges of the retinal inner nuclear layer, forming the deep vasculature that is parallel to the superifcial vasculature. The blood-retinal barrier is mainly composed of endothelium, basal lamina and the end-feet of astrocytes, which become mature during mouse development. Initially, the naive endothelial cells were immature with few organelles and many microvilli. The basal lamina was uniform in thickness, and the glial end-feet surrounded the outer basal lamina incompletely. In the end, the blood-retinal barrier matures with smooth endothelia connected through tight junctions, rela-tively thin and even basal lamina, and relatively thin glial cell end-feet. These ifndings indicate that the development of the vasculature in the retina follows the rules of“center to periphery”and“superifcial layer to deep layers”. Its development and maturation are spatially and tempo-rally consistent with the functional performance of retinal neurons and photosensitivity. The blood-retinal barrier gradually becomes mature via the process of interactions between astro-cytes and blood vessel cells.展开更多
Mechanobiological stimuli,such as low-intensity pulsed ultrasound(LIPUS),have been shown to promote bone regeneration and fresh fracture repair,but the fundamental biophysical mechanisms involved remain elusive.Here,w...Mechanobiological stimuli,such as low-intensity pulsed ultrasound(LIPUS),have been shown to promote bone regeneration and fresh fracture repair,but the fundamental biophysical mechanisms involved remain elusive.Here,we propose that a mechanosensitive ion channel of Piezo1 plays a pivotal role in the noninvasive ultrasound-induced mechanical transduction pathway to trigger downstream cellular signal processes.This study aims to investigate the expression and role of Piezo1 in MC3T3-E1 cells after LIPUS treatment.Immunofluorescence analysis shows that Piezo1 was present on MC3T3-E1 cells and could be ablated by shRNA transfection.MC3T3-E1 cell migration and proliferation were significantly increased by LIPUS stimulation,and knockdown of Piezo1 restricted the increase in cell migration and proliferation.After labeling with Fluo-8,MC3T3-E1 cells exhibited fluorescence intensity traces with several high peaks compared with the baseline during LIPUS stimulation.No obvious change in the fluorescence intensity tendency was observed after LIPUS stimulation in shRNA-Piezo1 cells,which was similar to the results in the GsMTx4-treated group.The phosphorylation ratio of ERK1/2 in MC3T3-E1 cells was significantly increased(P<0.01)after LIPUS stimulation.In addition,Phalloidin-iFluor-labeled F-actin filaments immediately accumulated in the perinuclear region after LIPUS stimulation,continued for 5 min,and then returned to their initial levels at 30 min.These results suggest that Piezo1 can transduce LIPUS-induced mechanical signals into intracellular calcium.The influx of Ca2+serves as a second messenger to activate ERK1/2 phosphorylation and perinuclear F-actin filament polymerization,which regulate the proliferation of MC3T3-E1 cells.展开更多
To satisfy the requirements of real-time and high quality mosaics, a bionic compound eye visual system was designed by simulating the visual mechanism of a fly compound eye. Several CCD cameras were used in this syste...To satisfy the requirements of real-time and high quality mosaics, a bionic compound eye visual system was designed by simulating the visual mechanism of a fly compound eye. Several CCD cameras were used in this system to imitate the small eyes of a compound eye. Based on the optical analysis of this system, a direct panoramic image mosaic algorithm was proposed. Several sub-images were collected by the bionic compound eye visual system, and then the system obtained the overlapping proportions of these sub-images and cut the overlap sections of the neighboring images. Thus, a panoramic image with a large field of view was directly mosaicked, which expanded the field and guaranteed the high resolution. The experimental results show that the time consumed by the direct mosaic algorithm is only 2.2% of that by the traditional image mosaic algorithm while guaranteeing mosaic quality. Furthermore, the proposed method effectively solved the problem of misalignment of the mosaic image and eliminated mosaic cracks as a result of the illumination factor and other factors. This method has better real-time properties compared to other methods.展开更多
The effects of the initial cloud condensation nuclei (CCN) concentrations (100-3000 mg-1) on hail properties were investigated in an idealized non-severe hail storm experiment using the Weather Research and Foreca...The effects of the initial cloud condensation nuclei (CCN) concentrations (100-3000 mg-1) on hail properties were investigated in an idealized non-severe hail storm experiment using the Weather Research and Forecasting (WRF) model, with the National Severe Storms Laboratory 2-moment microphysics scheme. The initial CCN concentration (CCNC) had obvious non-monotonic effects on the mixing ratio, number concentrations, and radius of hail, both in clouds and at the surface, with a CCNC threshold between 300 and 500 mg-1. An increasing CCNC is conducive (suppressive) to the amount of surface hail precipitation below (above) the CCNC threshold. The non-monotonic effects were due to both the thermodynamics and microphysics. Below the CCNC threshold, the mixing ratios with the increasing CCNC, resulting in more latent heat released of cloud droplets and ice crystals increased dramatically from condensation and frozen between 4 and 8 km and intensified updraft volume. The extent of the riming process, which is the primary process for hail production, increased dramatically. Above the CCNC threshold, the mixing ratio of cloud droplets and ice crystals increased continuously, but the maximum updraft volume was weakened because of reduced frozen latent heating at low level. The smaller ice crystals reduced the formation of hail and smaller clouds, with decreased rain water reducing riming efficiency so that graupel and hail also decreased with increasing CCNC, which is unfavorable for hail growth.展开更多
A novel magnetic levitation support method is proposed, which can relieve the perturbation caused by traditional support methods andprovide more accurate position control of the capsule. This method can keep the perfe...A novel magnetic levitation support method is proposed, which can relieve the perturbation caused by traditional support methods andprovide more accurate position control of the capsule. This method can keep the perfect symmetry of the octahedral spherical hohlraum and hasthe characteristics in stability, tunability and simplicity. It is also favorable that all the results, such as supporting forces acting on the super-conducting capsule, are calculated analytically, and numerical simulations are performed to verify these results. A typical realistic design isproposed and discussed in detail. The superconducting coating material is suggested, and the required superconducting properties are listed.Damped oscillation of the floating capsule in thin helium gas is discussed, and the restoring time is estimated.展开更多
Objective:To explore the structural and functional characteristics of microbiota in oropharynx of subhealthy children with gastrointestinal heat retention syndrome(GHRS)differentiated by traditional Chinese medicine,a...Objective:To explore the structural and functional characteristics of microbiota in oropharynx of subhealthy children with gastrointestinal heat retention syndrome(GHRS)differentiated by traditional Chinese medicine,and screen the biometric operational taxonomic units(OTUs)to assist the clinical diagnosis.Methods:We recruited children according to the“GHRS diagnostic scale”,collected their oropharyngeal swabs,and sequenced the 16 SrDNA V4 region.We described the bacterial structure with alpha-indexes,beta-distances,and relative abundances;moreover,we screened the differential genera/OTUs with Wilcoxon rank-sum test,Metagenome Seq analysis,and linear discriminant analysis effect size(LEf Se)analysis,in which biometric OTUs were selected to construct the receiver operating characteristic curve to verify the diagnostic value.The bacterial function was predicted with Kyoto Encyclopedia of Genes and Genomes pathways according to 16S rDNA gene by using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States.Results:The study population was composed of 10 children with GHRS and 10 healthy control children.GHRS children were more likely to overeat(gluttony,P=.033).Alpha-indexes,such as Sobs,abundancebased coverage estimator,Bootstrap,and Qstat,were significantly higher in the GHRS group,while betadistances did not exhibit any significant intergroup differences.There were 9 differently distributed nonpredominant genera between the groups in Wilcoxon rank-sum test,as well as 13 non-predominant genera in Metagenome Seq analysis and 3 non-predominant OTUs in LEfSe analysis.OTU44 and OTU196 were used to construct the receiver operating characteristic curve,and the area under curve was 0.92.Predicted functions showed that pathways related to oxidative phosphorylation and carbon metabolism were enriched in healthy control samples,while the pathway related to renin secretion was remarkably enriched in GHRS samples.Conclusion:Unique oropharyngeal microbial structure and function were identified in GHRS children.OTU44 and OTU196 were specific OTUs,which could be used as biomarkers of GHRS to assist clinical diagnosis.展开更多
The primary and secondary arcs volt-ampere characteristics of low earth orbit solar arrays are studied in this research. Using three gallium-arsenide solar cell samples, the gap lengths of the solar cell are set to 1,...The primary and secondary arcs volt-ampere characteristics of low earth orbit solar arrays are studied in this research. Using three gallium-arsenide solar cell samples, the gap lengths of the solar cell are set to 1, 2, and 3 mm. First, the primary arc voltage characteristics of a solar array are analyzed. It is found that two steps are involved in the primary arc voltages, which are 116 and 22 V according to our experiment and are independent of the electrostatic discharge current and the gap lengths. By comparing with the arc pattern, we determined that current chopping may be the reason for the stepped arc voltage. Then, the characteristics of the secondary arc of the solar array are demonstrated. The study shows that the secondary arc voltage values increase with the gap length. In the case of the same cell with a fixed gap length, the voltage of the secondary arc increases with the string current. Finally, the relationship between the secondary arc voltage and the gap length is obtained which helps the string voltage and the gap length selection for system design.展开更多
Glucose metabolism is fundamental for the functions of all tissues,including cartilage.Despite the emerging evidence related to glucose metabolism in the regulation of prenatal cartilage development,little is known ab...Glucose metabolism is fundamental for the functions of all tissues,including cartilage.Despite the emerging evidence related to glucose metabolism in the regulation of prenatal cartilage development,little is known about the role of glucose metabolism and its biochemical basis in postnatal cartilage growth and homeostasis.We show here that genetic deletion of the glucose transporter Glutl in postnatal cartilage impairs cell proliferation and matrix production in growth plate(GPs)but paradoxically increases cartilage remnants in the metaphysis,resulting in shortening of long bones.On the other hand,articular cartilage(AC)with Glutl deficiency presents diminished cellularity and loss of proteoglycans,which ultimately progress to cartilage fibrosis.Moreover,predisposition to Glutl deficiency severely exacerbates injury-induced osteoarthritis.Regardless of the disparities in glucose metabolism between GP and AC chondrocytes under normal conditions,both types of chondrocytes demonstrate metabolic plasticity to enhance glutamine utilization and oxidation in the absence of glucose availability.However,uncontrolled glutamine flux causes collagen overmodification,thus affecting extracellular matrix remodeling in both cartilage compartments.These results uncover the pivotal and distinct roles of Glutl-mediated glucose metabolism in two of the postnatal cartilage compartments and link some cartilage abnormalities to altered glucose/glutamine metabolism.展开更多
基金supported by the China Scholarship Council(to YW)the Swedish Research Council,No.2018-02601(to MS)+7 种基金the Alzheimer Foundation,No.AF-980695(to MS)the Stockholm County Council,No.RS2020-0731(to MS)the Foundation of Old Servants(to MS)the Gun and Bertil Stohne Foundation(to MS)the?hlén Foundation,No.233055(to MS)The Swedish Fund for Research without Animal Experiments(to MS)the Swedish Dementia Foundation(to MS)the Brain foundation,No.FO2022-0131(to MS)。
文摘Specialized pro-resolving lipid mediators including maresin 1 mediate resolution but the levels of these are reduced in Alzheimer's disease brain, suggesting that they constitute a novel target for the treatment of Alzheimer's disease to prevent/stop inflammation and combat disease pathology. Therefore, it is important to clarify whether they counteract the expression of genes and proteins induced by amyloid-β. With this objective, we analyzed the relevance of human monocyte–derived microglia for in vitro modeling of neuroinflammation and its resolution in the context of Alzheimer's disease and investigated the pro-resolving bioactivity of maresin 1 on amyloid-β42–induced Alzheimer's disease–like inflammation. Analysis of RNA-sequencing data and secreted proteins in supernatants from the monocyte-derived microglia showed that the monocyte-derived microglia resembled Alzheimer's disease–like neuroinflammation in human brain microglia after incubation with amyloid-β42. Maresin 1 restored homeostasis by down-regulating inflammatory pathway related gene expression induced by amyloid-β42 in monocyte-derived microglia, protection of maresin 1 against the effects of amyloid-β42 is mediated by a re-balancing of inflammatory transcriptional networks in which modulation of gene transcription in the nuclear factor-kappa B pathway plays a major part. We pinpointed molecular targets that are associated with both neuroinflammation in Alzheimer's disease and therapeutic targets by maresin 1. In conclusion, monocyte-derived microglia represent a relevant in vitro microglial model for studies on Alzheimer's disease-like inflammation and drug response for individual patients. Maresin 1 ameliorates amyloid-β42–induced changes in several genes of importance in Alzheimer's disease, highlighting its potential as a therapeutic target for Alzheimer's disease.
基金supported by the National Natural Science Foundation of China (41630754, 41671067, and 41501063)the Chinese Academy of Sciences (KJZD-EW-G03-04), the State Key Laboratory of Cryosphere Science (SKLCS-ZZ-2015)the Foundation for Excellent Youth Scholars of Northwest Institute of Eco-Environment and Resources, CAS
文摘Light-absorbing impurities on glaciers are important factors that influence glacial surface albedo and accelerate glacier melt. In this study, the quantity of light-absorbing impurities on Keqikaer Glacier in western Tien Shan, Central Asia, was measured. We found that the average concentrations of black carbon was 2,180 ng/g, with a range from 250 ng/g to more than 10,000 ng/g. The average concentrations of organic carbon and mineral dust were 1,738 ng/g and 194 μg/g, respectively. Based on simulations performed with the Snow Ice Aerosol Radiative model simulations, black carbon and dust are responsible for approximately 64% and 9%, respectively, of the albedo reduction, and are associated with instantaneous radiative forcing of 323.18 W/m2(ranging from 142.16 to 619.25 W/m2) and 24.05 W/m2(ranging from 0.15 to69.77 W/m2), respectively. For different scenarios, the albedo and radiative forcing effect of black carbon is considerably greater than that of dust. The estimated radiative forcing at Keqikaer Glacier is higher than most similar values estimated by previous studies on the Tibetan Plateau, perhaps as a result of black carbon enrichment by melt scavenging. Light-absorbing impurities deposited on Keqikaer Glacier appear to mainly originate from central Asia, Siberia, western China(including the Taklimakan Desert) and parts of South Asia in summer, and from the Middle East and Central Asia in winter.A footprint analysis indicates that a large fraction(>60%) of the black carbon contributions on Keqikaer Glacier comes from anthropogenic sources. These results provide a scientific basis for regional mitigation efforts to reduce black carbon.
基金This study was supported by the National Key Research and Development Program(Grant No.2016YFD0600205).
文摘In southern China,the eucalyptus plantation industry has been severely restricted by government policy over concerns on negative environmental impacts.In its place,large-scale plantations of high-value tropical tree species such as nitrogen-fixing Dalbergia odorifera and hemiparasite Santalum album have been widely cultivated including in mixed-species plantations.However,despite their poor growth,little information is available on suitable silvicultural practices of these plantations.Therefore,we subjected an 8-year-old mixed stand of D.odorifera and S.album to weeding,fertilization,weeding+fertilization,or no(CK)treatments and measured soil microbial biomass,respiration,nutrients,nitrogen mineralization and leaching and tree growth and litter production.Weeding and fertilization decreased microbial biomass but increased soil respiration,inhibited mineralization,had not effect on leaching of soil nitrogen,and improved the nutrient status of plantation soil.All practices improved the growth of D.odorifera.In the mixed plantation,fertilization increased litter production and nutrient content,but weeding and weeding+fertilization decreased growth of S.album and litter production in mixed plantation because weeding decreased the number of S.album haustoria in underground plant roots.In conclusion,fertilization is recommended;however,weeding-related practices are inappropriate for D.odorifera and S.album mixed plantations.These conclusions have important implications for managing other parasite or mixed-species plantations.
基金supported by National Natural Science Foundation of China(No.61673030,U1613209)Science and Technology Plan Project of Shenzhen(No.JCYJ20200109140410340).
文摘This article proposes a deep neural network(DNN)-based direct-path relative transfer function(DP-RTF)enhancement method for robust direction of arrival(DOA)estimation in noisy and reverberant environments.The DP-RTF refers to the ratio between the directpath acoustic transfer functions of the two microphone channels.First,the complex-value DP-RTF is decomposed into the inter-channel intensity difference,and sinusoidal functions of the inter-channel phase difference in the time-frequency domain.Then,the decomposed DP-RTF features from a series of temporal context frames are utilized to train a DNN model,which maps the DP-RTF features contaminated by noise and reverberation to the clean ones,and meanwhile provides a time-frequency(TF)weight to indicate the reliability of the mapping.The DP-RTF enhancement network can help to enhance the DP-RTF against noise and reverberation.Finally,the DOA of a sound source can be estimated by integrating the weighted matching between the enhanced DP-RTF features and the DP-RTF templates.Experimental results on simulated data show the superiority of the proposed DP-RTF enhancement network for estimating the DOA of the sound source in the environments with various levels of noise and reverberation.
基金Supported by Project of Shaanxi Administration of Traditional Chinese Medicine(zy06)Special Project of Education Department of Shaanxi Provincial Government(12JK1016)Program of Shaanxi Provincial Department of Science and Technology(2013jk4023)
文摘[Objectives] To study the protection of compatibility of Saikosapon d and Baicalin on carbon tetrachloride( CCl_4) injured L-02 cells. [Methods] Normal human hepatocyte cell line L-02 cells were cultured in vitro,and CCl_4 was used to induce hepatocellular injury. Interventions were carried out with Saikosaponin d and Baicalin at different dosage. The proliferation of L-02 cells in each group was determined by methylthiazolyl tetrazolium( MTT) assay; the levels of AST and ALT in the culture supernatants were detected by enzyme-linked immunosorbent assay( ELISA); the expressions of TLR4 and NFκBp65 proteins in each group were determined by immunohistochemistry.[Results] In the CCl_4 injured group,the proliferation of L-02 cells was significantly declined,the levels of AST and ALT in cell culture medium were significantly increased,and the expressions of TLR4 and NFκBp65 in L-02 cells were increased; after the intervention of Saikosaponin d and Baicalin,1. 75 μg/mL group and 1. 5 μg/mL group had an effect of promoting the proliferation of L-02 cells and could reduce the levels of AST and ALT in the cell culture medium,and TLR4 and NFκBp65 proteins in L-02 cells also had a certain inhibitory effect. [Conclusions] The compatibility of Saikosapon d and Baicalin has a certain protective effect on CCl_4 injured L-02 cells. The protection mechanism may be related with its down-regulating TLR4-NFκB signaling pathway and reducing the inflammation.
基金Supported by Student’s Platform for Innovation and Entrepreneurship Training Program at the State Level(202110414021)。
文摘Based on the existing literature,this paper analyzed and explored the factors that affect the efficiency of resource allocation,and evaluated the current situation of resource allocation in various fields.It is found that with the emergence of the new pattern of China’s economic development,the economic growth rate has slowed down,and the method of large-scale production driving economic growth is no longer applicable to the current economic situation.Nowadays,when structural transformation and upgrading have entered a new stage,to achieve the optimization of resource allocation efficiency,it is necessary to start from three aspects:improving information transparency,upgrading industrial structure,and planning government intervention.Through the adaptation analysis of blockchain technology and the existing problems in optimizing resource allocation efficiency,it explored the feasibility of blockchain technology to optimize resource allocation efficiency,and promote economical,efficient and high-quality development.
基金Supported by National Innovation Planning Project for University Students in 2021 (202110414021)
文摘With the rapid development of Internet technology,the importance of blockchain technology has become increasingly prominent.Faced with this situation,extensive research has been carried out at home and abroad.Through the analysis of relevant literature on blockchain in recent years,it is found that there are many research results of blockchain technology in medical care,finance,education,etc.,but its application in the field of resource allocation efficiency is rare.From the existing studies on the influencing factors of resource allocation efficiency in China,it is found that there are significant differences in resource allocation efficiency between China and some developed countries or between various provinces and cities of China.
基金funded by the National Key Research and Development Program(grant number 2017YFD0601100)。
文摘Little is known about C-N-P stoichiometries and content in teak(Tectona grandis)plantations in South China,which are mostly sited on hilly areas with lateritic soil,and the effect of slope position on the accumulation of these elements in trees and rhizosphere soils.Here we analyzed the C,N,P content and stoichiometry in leaves,fine roots and rhizosphere soils of trees on the upper and lower slopes of a 12-year-old teak plantation.The Kraft classification system of tree status was used to sample dominant,subdominant and mean trees at each slope position.The results showed that the C,N and P contents in leaves were higher than in fine roots and rhizosphere soils.The lowest C/N,C/P and N/P ratios were found in rhizosphere soils,and the C/N and C/P ratios in fine roots were higher than in leaves.Nutrient accumulation in leaves,fine roots and rhizosphere soils were significantly influenced by slope position and tree class with their interaction mainly showing a greater effect on rhizosphere soils.Leaf C content and C/N ratio,fine root C and P contents,and C/N and C/P ratios all increased distinctly with declining slope position.The contents of organic matter(SOM),ammonium(NH4+-N),nitrate-nitrogen(NO3--N)and available potassium(AK)in rhizosphere soils were mainly enriched on upper slopes,but exchange calcium(ECa),available phosphorus(AP),and pH were relatively lower.Variations in the C,N and P stoichiometries in trees were mainly attributed to the differences in rhizosphere soil properties.N and P contents showed significant positive linear relationships between leaf and rhizosphere soil,and C content negative linear correlation among leaves,fine roots and rhizosphere soils.Chemical properties of rhizosphere soils,particularly C/N and NH4+-N,had significant effects on the leaf nutrients in trees on the upper slope.Correspondingly,rhizosphere soil properties mainly influenced fine root nutrients on the lower slope,and soil AK was the major influencing factor.Overall,these results offer new insights for the sustainability and management of teak plantations in hilly areas.
基金supported by the National Natural Science Foundation of China(42201158,42177366)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0605)+1 种基金Natural Science Foundation of Gansu Province,China(23JRRA656)the State Key Laboratory of Cryospheric Science(SKLCS-ZZ-2022).
文摘As an important component of carbonaceous matters,dissolved organic carbon(DOC)can absorb and scatter the solar radiation at ultraviolet and blue wavelengths.The wet deposition process has great impact on the con-centration and light absorption ability of precipitation DOC,affecting the climatic effect caused by DOC in the atmosphere.In this study,light absorption and fluorescence characteristics of precipitation DOC was investigated in the central Tibetan Plateau(TP).The results showed that the mean DOC concentration and mass absorption cross-section measured at 365 nm(MAC_(365)) in Tanggula(TGL)station were 0.59±0.42 mg/L and 0.37±0.19 m^(2)/g,respectively,while both values showed much higher volatilities than those of aerosols.DOC concentrations had significant negative correlation with the precipitation amount,while MAC_(365) values increase with the precipitation amount in TGL station.Therefore,DOC with high light-absorbing ability was preferred to be retained in the atmosphere during wet deposition.In this study,precipitation DOC contained three fluorescent components(one humic-like component and two tyrosine-like components)mainly from local biomass burning sources.DOC concentration showed a negative relationship with MAC_(365) value in TGL station.The wet deposition of DOC with low light-absorbing ability can reduce the strong negative radiative forcing caused by secondary organic aerosol due to high proportion of DOC in secondary organic carbon.Similar phenomenon was also found in Nam Co,Lulang and Everest stations of previous study,which may have a potential impact on radiative forcing in the atmosphere of TP.
基金supported by the Shenzhen Science and Technology Program(JSGG20220606142803007)the Shenzhen Institute of Artificial Intelligence and Robotics for Society(AIRS).
文摘Moving humans,agents,and subjects bring many challenges to robot self‐localisation and environment perception.To adapt to dynamic environments,SLAM researchers typically apply several deep learning image segmentation models to eliminate these moving obstacles.However,these moving obstacle segmentation methods cost too much computation resource for the onboard processing of mobile robots.In the current industrial environment,mobile robot collaboration scenario,the noise of mobile robots could be easily found by on‐board audio‐sensing processors and the direction of sound sources can be effectively acquired by sound source estimation algorithms,but the distance estimation of sound sources is difficult.However,in the field of visual perception,the 3D structure information of the scene is relatively easy to obtain,but the recognition and segmentation of moving objects is more difficult.To address these problems,a novel vision‐audio fusion method that combines sound source localisation methods with a visual SLAM scheme is proposed,thereby eliminating the effect of dynamic obstacles on multi‐agent systems.Several heterogeneous robots experiments in different dynamic scenes indicate very stable self‐localisation and environment reconstruction performance of our method.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1404400)the National Natural Science Foundation of China(Grant No.12274315)+1 种基金a Project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Postgraduate Research and Practice Innovation Program of Jiangsu Province(Grant No.KYCX23_3228)。
文摘The control of the pseudospin of sound wave has attracted increasing attention in recent years.Utilizing the finite-size effect of topological acoustics,we successfully construct an H-shaped acoustic topological pseudospin switcher that sound wave energy can be easily switched through different passages.The interesting phenomenon of pseudospin flipping is numerically and experimentally demonstrated.A quantitative interference theory is proposed that the constructive and destructive interference of pseudospin states leads to pseudospin flipping and preserving in multiple frequencies.We verify the key parameters of the design,including the length of the passage and its interface state dispersion,and the theory can be extended to other topology acoustics and photonics systems.Moreover,the tunable topological sonic crystal we use provides adjustable convenience to pseudospin switcher design.The pseudospin switching behavior offers an efficient method to control the acoustic topological edge state transport,which has great potential in versatile applications,such as integrated acoustics,acoustic security,and information processing.
基金supported by the National Natural Science Foundation of China,No.30771140,31070952 and U1204311
文摘Astrocytes are intimately involved in the formation and development of retinal vessels. Astrocyte dysfunction is a major cause of blood-retinal barrier injury and other retinal vascular diseases. In this study, the development of the retinal vascular system and the formation of the blood-ret-inal barrier in mice were investigated using immunolfuorescence staining, gelatin-ink perfusion, and transmission electron microscopy. The results showed that the retinal vascular system of mice develops from the optic disc after birth, and radiates out gradually to cover the entire retina, taking the papilla optica as the center. First, the superifcial vasculature is formed on the inner retinal layer;then, the vasculature extends into the inner and outer edges of the retinal inner nuclear layer, forming the deep vasculature that is parallel to the superifcial vasculature. The blood-retinal barrier is mainly composed of endothelium, basal lamina and the end-feet of astrocytes, which become mature during mouse development. Initially, the naive endothelial cells were immature with few organelles and many microvilli. The basal lamina was uniform in thickness, and the glial end-feet surrounded the outer basal lamina incompletely. In the end, the blood-retinal barrier matures with smooth endothelia connected through tight junctions, rela-tively thin and even basal lamina, and relatively thin glial cell end-feet. These ifndings indicate that the development of the vasculature in the retina follows the rules of“center to periphery”and“superifcial layer to deep layers”. Its development and maturation are spatially and tempo-rally consistent with the functional performance of retinal neurons and photosensitivity. The blood-retinal barrier gradually becomes mature via the process of interactions between astro-cytes and blood vessel cells.
基金supported by the National Institute of Health(R01AR052379 and R01AR61821,YXQ)GZ is partially supported by a fellowship from the Dental School of the Chinese Medical University during his studies at Stony Brook University.
文摘Mechanobiological stimuli,such as low-intensity pulsed ultrasound(LIPUS),have been shown to promote bone regeneration and fresh fracture repair,but the fundamental biophysical mechanisms involved remain elusive.Here,we propose that a mechanosensitive ion channel of Piezo1 plays a pivotal role in the noninvasive ultrasound-induced mechanical transduction pathway to trigger downstream cellular signal processes.This study aims to investigate the expression and role of Piezo1 in MC3T3-E1 cells after LIPUS treatment.Immunofluorescence analysis shows that Piezo1 was present on MC3T3-E1 cells and could be ablated by shRNA transfection.MC3T3-E1 cell migration and proliferation were significantly increased by LIPUS stimulation,and knockdown of Piezo1 restricted the increase in cell migration and proliferation.After labeling with Fluo-8,MC3T3-E1 cells exhibited fluorescence intensity traces with several high peaks compared with the baseline during LIPUS stimulation.No obvious change in the fluorescence intensity tendency was observed after LIPUS stimulation in shRNA-Piezo1 cells,which was similar to the results in the GsMTx4-treated group.The phosphorylation ratio of ERK1/2 in MC3T3-E1 cells was significantly increased(P<0.01)after LIPUS stimulation.In addition,Phalloidin-iFluor-labeled F-actin filaments immediately accumulated in the perinuclear region after LIPUS stimulation,continued for 5 min,and then returned to their initial levels at 30 min.These results suggest that Piezo1 can transduce LIPUS-induced mechanical signals into intracellular calcium.The influx of Ca2+serves as a second messenger to activate ERK1/2 phosphorylation and perinuclear F-actin filament polymerization,which regulate the proliferation of MC3T3-E1 cells.
文摘To satisfy the requirements of real-time and high quality mosaics, a bionic compound eye visual system was designed by simulating the visual mechanism of a fly compound eye. Several CCD cameras were used in this system to imitate the small eyes of a compound eye. Based on the optical analysis of this system, a direct panoramic image mosaic algorithm was proposed. Several sub-images were collected by the bionic compound eye visual system, and then the system obtained the overlapping proportions of these sub-images and cut the overlap sections of the neighboring images. Thus, a panoramic image with a large field of view was directly mosaicked, which expanded the field and guaranteed the high resolution. The experimental results show that the time consumed by the direct mosaic algorithm is only 2.2% of that by the traditional image mosaic algorithm while guaranteeing mosaic quality. Furthermore, the proposed method effectively solved the problem of misalignment of the mosaic image and eliminated mosaic cracks as a result of the illumination factor and other factors. This method has better real-time properties compared to other methods.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41330421 and 41461164006)the Chinese 973 program (Grant No. 2013CB430104)
文摘The effects of the initial cloud condensation nuclei (CCN) concentrations (100-3000 mg-1) on hail properties were investigated in an idealized non-severe hail storm experiment using the Weather Research and Forecasting (WRF) model, with the National Severe Storms Laboratory 2-moment microphysics scheme. The initial CCN concentration (CCNC) had obvious non-monotonic effects on the mixing ratio, number concentrations, and radius of hail, both in clouds and at the surface, with a CCNC threshold between 300 and 500 mg-1. An increasing CCNC is conducive (suppressive) to the amount of surface hail precipitation below (above) the CCNC threshold. The non-monotonic effects were due to both the thermodynamics and microphysics. Below the CCNC threshold, the mixing ratios with the increasing CCNC, resulting in more latent heat released of cloud droplets and ice crystals increased dramatically from condensation and frozen between 4 and 8 km and intensified updraft volume. The extent of the riming process, which is the primary process for hail production, increased dramatically. Above the CCNC threshold, the mixing ratio of cloud droplets and ice crystals increased continuously, but the maximum updraft volume was weakened because of reduced frozen latent heating at low level. The smaller ice crystals reduced the formation of hail and smaller clouds, with decreased rain water reducing riming efficiency so that graupel and hail also decreased with increasing CCNC, which is unfavorable for hail growth.
文摘A novel magnetic levitation support method is proposed, which can relieve the perturbation caused by traditional support methods andprovide more accurate position control of the capsule. This method can keep the perfect symmetry of the octahedral spherical hohlraum and hasthe characteristics in stability, tunability and simplicity. It is also favorable that all the results, such as supporting forces acting on the super-conducting capsule, are calculated analytically, and numerical simulations are performed to verify these results. A typical realistic design isproposed and discussed in detail. The superconducting coating material is suggested, and the required superconducting properties are listed.Damped oscillation of the floating capsule in thin helium gas is discussed, and the restoring time is estimated.
基金supported by the National Natural Science Foundation of China(81373769)the Scientific Research and Postgraduate Training Co-construction Project of Beijing Municipal Education Commission(1000062520115)the Province Natural Science Foundation of Beijing(7172131)。
文摘Objective:To explore the structural and functional characteristics of microbiota in oropharynx of subhealthy children with gastrointestinal heat retention syndrome(GHRS)differentiated by traditional Chinese medicine,and screen the biometric operational taxonomic units(OTUs)to assist the clinical diagnosis.Methods:We recruited children according to the“GHRS diagnostic scale”,collected their oropharyngeal swabs,and sequenced the 16 SrDNA V4 region.We described the bacterial structure with alpha-indexes,beta-distances,and relative abundances;moreover,we screened the differential genera/OTUs with Wilcoxon rank-sum test,Metagenome Seq analysis,and linear discriminant analysis effect size(LEf Se)analysis,in which biometric OTUs were selected to construct the receiver operating characteristic curve to verify the diagnostic value.The bacterial function was predicted with Kyoto Encyclopedia of Genes and Genomes pathways according to 16S rDNA gene by using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States.Results:The study population was composed of 10 children with GHRS and 10 healthy control children.GHRS children were more likely to overeat(gluttony,P=.033).Alpha-indexes,such as Sobs,abundancebased coverage estimator,Bootstrap,and Qstat,were significantly higher in the GHRS group,while betadistances did not exhibit any significant intergroup differences.There were 9 differently distributed nonpredominant genera between the groups in Wilcoxon rank-sum test,as well as 13 non-predominant genera in Metagenome Seq analysis and 3 non-predominant OTUs in LEfSe analysis.OTU44 and OTU196 were used to construct the receiver operating characteristic curve,and the area under curve was 0.92.Predicted functions showed that pathways related to oxidative phosphorylation and carbon metabolism were enriched in healthy control samples,while the pathway related to renin secretion was remarkably enriched in GHRS samples.Conclusion:Unique oropharyngeal microbial structure and function were identified in GHRS children.OTU44 and OTU196 were specific OTUs,which could be used as biomarkers of GHRS to assist clinical diagnosis.
基金supported by National Natural Science Foundation of China (No. 51407008)
文摘The primary and secondary arcs volt-ampere characteristics of low earth orbit solar arrays are studied in this research. Using three gallium-arsenide solar cell samples, the gap lengths of the solar cell are set to 1, 2, and 3 mm. First, the primary arc voltage characteristics of a solar array are analyzed. It is found that two steps are involved in the primary arc voltages, which are 116 and 22 V according to our experiment and are independent of the electrostatic discharge current and the gap lengths. By comparing with the arc pattern, we determined that current chopping may be the reason for the stepped arc voltage. Then, the characteristics of the secondary arc of the solar array are demonstrated. The study shows that the secondary arc voltage values increase with the gap length. In the case of the same cell with a fixed gap length, the voltage of the secondary arc increases with the string current. Finally, the relationship between the secondary arc voltage and the gap length is obtained which helps the string voltage and the gap length selection for system design.
基金This work was supported by the following NIH/NIAMS grants:R01 grants(AR069605 and AR079100 to RJ.O.as well as AR075860 and AR077616 to J.S.),an R21 grant(AR077226 to J.S.),a P30 Core Center grant(AR057235 to Musculoskeletal Research Center)an NCI grant(R35ES028365 to G.P.).
文摘Glucose metabolism is fundamental for the functions of all tissues,including cartilage.Despite the emerging evidence related to glucose metabolism in the regulation of prenatal cartilage development,little is known about the role of glucose metabolism and its biochemical basis in postnatal cartilage growth and homeostasis.We show here that genetic deletion of the glucose transporter Glutl in postnatal cartilage impairs cell proliferation and matrix production in growth plate(GPs)but paradoxically increases cartilage remnants in the metaphysis,resulting in shortening of long bones.On the other hand,articular cartilage(AC)with Glutl deficiency presents diminished cellularity and loss of proteoglycans,which ultimately progress to cartilage fibrosis.Moreover,predisposition to Glutl deficiency severely exacerbates injury-induced osteoarthritis.Regardless of the disparities in glucose metabolism between GP and AC chondrocytes under normal conditions,both types of chondrocytes demonstrate metabolic plasticity to enhance glutamine utilization and oxidation in the absence of glucose availability.However,uncontrolled glutamine flux causes collagen overmodification,thus affecting extracellular matrix remodeling in both cartilage compartments.These results uncover the pivotal and distinct roles of Glutl-mediated glucose metabolism in two of the postnatal cartilage compartments and link some cartilage abnormalities to altered glucose/glutamine metabolism.