期刊文献+
共找到300篇文章
< 1 2 15 >
每页显示 20 50 100
THEORETICAL AND EXPERIMENTAL RESEARCH ON DYNAMIC BEHAVIOR OF GUYED MASTS UNDER WIND LOAD 被引量:3
1
作者 MaXing WangZhonggang +1 位作者 DengHongzhou WangZhaomin 《Acta Mechanica Solida Sinica》 SCIE EI 2004年第2期166-171,共6页
A frequency-domain algorithm is presented for the dynamic analysis of guyed masts. By introducing a four-degrees-of-freedom model of a suspended cable, guyed masts are simpli?ed as an equivalent cable-beam model. Th... A frequency-domain algorithm is presented for the dynamic analysis of guyed masts. By introducing a four-degrees-of-freedom model of a suspended cable, guyed masts are simpli?ed as an equivalent cable-beam model. Then, based on the discrete random vibration theory, recurrence formulas for the statistical moments of the wind-induced behavior of guyed masts are developed with the wind load treated as ?ltered white noise excitation. The dynamic analysis of a two-level guyed mast has been illustrated. Finally, results from a wind-tunnel experiment of guyed mast are used to testify the theory developed in this paper. 展开更多
关键词 guyed masts four-degrees-of-freedom cable model discrete random vibration wind tunnel experiment
在线阅读 下载PDF
Analysis of the Ultimate Bearing Capacity of Oil Field Drilling Masts 被引量:1
2
作者 Han Dongying Zhou Guoqiang Li Zifeng 《Petroleum Science》 SCIE CAS CSCD 2005年第3期33-36,共4页
In order to improve the safety of drilling operations, this paper presents a new method for forecasting the ultimate bearing capacity of oil field drilling masts. The method is based on a double nonlinear finite eleme... In order to improve the safety of drilling operations, this paper presents a new method for forecasting the ultimate bearing capacity of oil field drilling masts. The method is based on a double nonlinear finite element theory and applies a referential stress method for measuring defects and defacements. The lab mast model was analyzed using the proposed method. The relative error, which was less than 5.0% between the forecast results and the destructive experiment values,verified the correctness of this method. It also forecasts the ultimate bearing capacity for a local drilling mast. 展开更多
关键词 Drilling mast ultimate bearing capacity double nonlinearity referential stress method defects anddefacements
原文传递
Hydrodynamics numerical investigation of hoistable masts for underwater vehicles
3
作者 Zheng Lijie Hu Gangyi Xu Jian Qiu Lei 《Engineering Sciences》 EI 2011年第1期13-18,共6页
Using the unsteady incompressible Navier-Stokes equation as the governing equation, the large eddy simulation (LES) model is implemented to investigate the shedding of vortices, the flow pattern of turbulence, the uns... Using the unsteady incompressible Navier-Stokes equation as the governing equation, the large eddy simulation (LES) model is implemented to investigate the shedding of vortices, the flow pattern of turbulence, the unsteady pressure fluctuation and the time history of the lift coefficient and drag coefficient of hoistable masts with various mast shapes and various arrangements in this paper. Combining the FFT, combined time-frequency transform and wavelet power spectrum analysis, the characteristics of unsteady pressure can be obtained in both time and frequency domain. It shows that the main frequency of pressure fluctuation is near the frequency of vortex shedding in time domain using the FFT method. It can be inferred from the combined time-frequency transform that the unsteady pressure fluctuation has obviously the peak value and the second peak value in time domain. It could indicate that the fluctuation power varies from the fluctuation frequency through the power spectrum analysis. By the data analysis, it shows that the vortex shedding is the dominant cause of the periodically pressure fluctuation. And the interaction pattern of wake and interplay between wake and the walls of masts under different arrangements are also discussed in this paper. 展开更多
关键词 hoistable mast HYDRODYNAMICS numerical investigation
在线阅读 下载PDF
Multifunctional deployment of coilable masts via structural constraint synergistic control:Diagonal pretensioned modes and compression-twist decoupling strategies
4
作者 Yingying TANG Jinguo LIU Hao SHANG 《Science China(Technological Sciences)》 2025年第10期310-330,共21页
Coilable masts are extensively utilized in aerospace systems owing to their structural simplicity,reliability,and high deployment ratios.However,their application is constrained by compression-twist coupling motion du... Coilable masts are extensively utilized in aerospace systems owing to their structural simplicity,reliability,and high deployment ratios.However,their application is constrained by compression-twist coupling motion during deployment,which induces large structure deformations and displacements.To address this limitation,this study proposes a parallel chiral coilable mast with synergistic control strategies.This design transforms the conventional unidirectional compression-twist motion into a bidirectional synchronous pure sliding deployment.Three pretensioned modes were developed for a single-bay unit based on diagonal constraints,leveraging the critical role of diagonals in achieving structural bistability.A topologyoptimized multi-bay configuration enables directional rotation while maintaining structural stability via pretension modes.By redesigning structural constraints on the top and bottom disks,a decoupling strategy achieves pure linear motion at the top batten frame,significantly expanding the operational envelope.The parallel-designed chiral configuration is developed based on the synergistic control strategies of these two structural constraints.Numerical simulations and experimental validation confirm the effectiveness and feasibility of the synergistic control strategies.The chiral configuration facilitates multifunctional deployment capabilities in geometrically unconstrained environments,demonstrating substantial improvements over conventional designs. 展开更多
关键词 coilable mast structural constraint compression-twist coupling motion pretensioned mode synergistic control
原文传递
Mechanism of the action of apigenin and proanthocyanidins in alleviating sensitive skin
5
作者 Laijiao Wei Rongrong Deng +3 位作者 Shiqian Zheng Luoxuan Li Kezheng Wang Zhibin Shen 《日用化学工业(中英文)》 北大核心 2025年第5期601-610,共10页
To investigate the mechanisms of apigenin(API)and proanthocyanidins(PC)in soothing sensitive skin(SS),a mast cell degranulation model was established by stimulating RBL-2H3 cells with the calcium ionophore A23187.Base... To investigate the mechanisms of apigenin(API)and proanthocyanidins(PC)in soothing sensitive skin(SS),a mast cell degranulation model was established by stimulating RBL-2H3 cells with the calcium ionophore A23187.Based on the combinatorial experiments,it was found that when API and PC were combined at the molar ratios of 4∶1 and 2∶1,they exhibited the antagonistic effects on histamine release(combination index CI>1);when they are combined at the molar ratios of 1∶1,1∶2 or 1∶4,they showed the synergistic effects on histamine release(CI<1).Among them,the combination of API and PC at a molar ratio of 1∶1 showed the better potent synergistic antihistamine release effect(CI=0.70).Histamine is a hallmark of the mast cell degranulation,consequently,the combination of API and PC at a molar ratio of 1∶1 yields the better efficiency in inhibiting the mast cell degranulation with the lowest IC_(50)value.Compared to the utilization of API or PC alone,the IC_(50)value was reduced by 11.150 and 6.503μmol/L,respectively.Compared to the positive control paeonol(PA),the treatment with the combination significantly reduced theβ-hex secretion,decreased the F-actin cytoskeleton rearrangement,and markedly suppressed the release of TNF-α,IL-4,and MCP-1.Further studies on the signaling pathways related to the mast cell degranulation indicated that the combination effectively inhibited the intracellular Ca^(2+)influx and significantly suppressed the phosphorylation of calmodulin-dependent protein kinase(CaMK)and phospholipase C/protein kinase C(PLC/PKC).In summary,the combination of API and PC at a molar ratio of 1∶1 exhibited the better synergistic antagonistic effect on the histamine release,inhibited the mast cell degranulation model activation by reducing Ca^(2+)influx and inhibiting the activation of Ca^(2+)/CaMK and PLC/PKC pathways,stabilized the cell membranes,regulated the inflammatory factor secretion,and exerted an effect in alleviating sensitive skin. 展开更多
关键词 APIGENIN PROANTHOCYANIDINS mast cell sensitive skin soothing
在线阅读 下载PDF
Mild itching induced by food ingestion following epicutaneous sensitization
6
作者 Yutaka Kuroki Naritoshi Mizuta +3 位作者 Chika Toyao Sayaka Nishimoto Yuichiro Sato Hidemi Hattori 《Allergy Medicine》 2025年第3期58-64,共7页
Background:While mild itching may seem harmless,it can worsen over time,necessitating early treatment.Epicutaneous sensitization has recently gained attention.Oral exposure may promote immune tolerance,but ingestion a... Background:While mild itching may seem harmless,it can worsen over time,necessitating early treatment.Epicutaneous sensitization has recently gained attention.Oral exposure may promote immune tolerance,but ingestion after epicutaneous sensitization can trigger severe allergic responses.Therefore,this study focused on the initial stages of allergic symptoms before they become severe and investigated the mechanisms underlying food ingestion-induced mild itching following epicutaneous sensitization.Methods:Female mice were epicutaneously sensitized with ovalbumin(OVA).Scratching behavior was recorded,and serum and tissue samples were collected.Levels of OVA-specific immunoglobulin(Ig)E/IgG1,histamine,and mast cell protease-1(MCPT-1)were measured by ELISA.Histological analysis of skin tissues and immune cell infiltration was performed via staining.Results:OVA challenge following epicutaneous sensitization induced mild itching in the OVA group.Scratching behavior peaked between 1 and 2 h and persisted for 8 h before returning to baseline.This itching was accompanied by dynamic fluctuations in OVA-specific IgE and IgG1,histamine,and MCPT-1 levels.Histological analysis revealed increased epidermal thickness and granulocytic infiltration,particularly of mast cells and eosinophils,within 2 h of OVA challenge.Mast cell and eosinophil migration into the skin tissues was significant,with eosinophil migration into the dermis persisted despite normalization of histamine levels and mast cell degranulation.These results suggest that mast cells and eosinophils play significant roles even in mild itching.Conclusion:This study provides insights into the early immune responses involved in food allergies,contributing to a better understanding of how mild symptoms can progress to more severe reactions. 展开更多
关键词 Food allergy Epicutaneous sensitization ITCHING Mast cells EOSINOPHILS Immediate reaction
暂未订购
Pollen source affects acorn production in pedunculate oak(Quercus robur L.)
7
作者 Ryan McClory Richard H.Ellis +1 位作者 Martin Lukac Jo Clark 《Journal of Forestry Research》 2025年第1期77-85,共9页
Acorn production in oaks(Quercus spp.)shows considerable inter-annual variation,known as masting.The effects of pollen sourced from trees within or outside the stand on acorn production were investigated in pedunculat... Acorn production in oaks(Quercus spp.)shows considerable inter-annual variation,known as masting.The effects of pollen sourced from trees within or outside the stand on acorn production were investigated in pedunculate oak(Quercus robur L.)in an ancient mixed woodland during two moderate masting years.Comparisons were made between natural pollination,hand pollinations with out-of-stand pollen,in-stand pollen or a 1:1 combination of the two pollen sources,and for bagged flowers left unpollinated.After all treatments,>85%of the flowers or developing acorns were aborted between May and August of both years.When flowers were protected with pollen bags and no pollen added,no acorns were produced.In contrast,hand pollination with out-of-stand pollen produced the most acorns both years and significantly more than within-stand pollen or natural pollination in 2022.Hand pollination with out-of-stand or within-stand pollen provided significantly more acorns than natural pollination in 2023.In 2022,hand pollination with a 1:1 mixture of out-of-stand and within-stand pollen yielded an intermediate number of mature acorns between those for the out-of-stand and within-stand pollination treatments.The study provides clear evidence of maternal choice during acorn development in pedunculate oak and of the benefits of pollen supplementation.It also confirms that pedunculate oak is a fruit-maturation masting species;abortion of pollinated flowers and immature acorns determines a mast year(rather than the number of flowers produced)at this site. 展开更多
关键词 Quercus robur L. ACORNS MASTING Pedunculate oak POLLINATION
在线阅读 下载PDF
Hereditary alpha tryptasemia and clinical implications
8
作者 Ece Tüsüz Önata Öner Özdemir Süreyya Savaşan 《World Journal of Clinical Cases》 2025年第21期6-15,共10页
Hereditary alpha tryptasemia was first described in 2016 and is the most common(up to 72%)cause of elevated serum basal tryptase(TPS).The clinical presentation of this condition,which is caused by copy number gains in... Hereditary alpha tryptasemia was first described in 2016 and is the most common(up to 72%)cause of elevated serum basal tryptase(TPS).The clinical presentation of this condition,which is caused by copy number gains in the TPSAB1 gene encoding serumαTPS,is variable for each patient.Some patients are asymptomatic,whereas in others,especially those with increased mast cell activation,it has been associated with a higher risk of anaphylaxis.Better characterization of this entity is important to identify atrisk patients and to develop new treatment strategies.This review provided an overview of hereditary alpha tryptasemia and increased awareness of this condition by discussing the current information in the literature. 展开更多
关键词 Tryptasemia Autosomal dominant Hereditary alpha tryptasemia Mast cell Tyrosine kinase protein
暂未订购
From scRNA-seq to therapeutic targets:Unveiling the impact of activated mast cells on intestinal dysfunction in acute pancreatitis
9
作者 Bin Li 《World Journal of Gastroenterology》 2025年第25期122-127,共6页
Wei et al reported a comprehensive single-cell transcriptomic analysis of the small intestine during early acute pancreatitis(AP)and identified activated mast cells and their secretion of CCL5 as pivotal factors drivi... Wei et al reported a comprehensive single-cell transcriptomic analysis of the small intestine during early acute pancreatitis(AP)and identified activated mast cells and their secretion of CCL5 as pivotal factors driving gut barrier dysfunction.By integrating scRNA-seq with in vitro and in vivo functional assays,this study advances our understanding of the cellular and molecular events underlying AP-associated intestinal injury.In this commentary,I highlight the methodological innovations employed in the study,contextualize its findings in the literature,and propose directions for future research.As an avid researcher in single-cell sequen-cing,I approached this letter with a spirit of academic inquiry and welcome any further discussion or corrections that may enhance my understanding. 展开更多
关键词 Acute pancreatitis Single-cell RNA sequencing Mast cells CCL5 Intestinal barrier
暂未订购
Acupuncture at Weizhong(BL40)attenuates acetic acid-induced overactive bladder in rats by regulating brain neural activity through the modulation of mast cells and tibial nerves
10
作者 Xin Liu Chao-yue Zhang +9 位作者 Xiu-yu Du Shan-shan Li Yu-qing Wang Yi Zheng Han-zhi Deng Xiao-qin Fang Jia-ying Li Zu-qing Wang Shi-fen Xu Yi-qun Mi 《Journal of Integrative Medicine》 2025年第1期46-55,共10页
Objective The present study evaluated the effects of deep acupuncture at Weizhong acupoint(BL40)on bladder function and brain activity in a rat model of overactive bladder(OAB),and investigated the possible mechanisms... Objective The present study evaluated the effects of deep acupuncture at Weizhong acupoint(BL40)on bladder function and brain activity in a rat model of overactive bladder(OAB),and investigated the possible mechanisms around the acupuncture area that initiate the effects of acupuncture.Methods Adult female Sprague-Dawley rats were randomly divided into six groups,comprising a control group,model group,group treated with deep acupuncture at BL40,group treated with shallow acupuncture at BL40,group treated with acupuncture at non-acupoint next to BL40,and group treated with acupuncture at Xuanzhong(GB39).Urodynamic evaluation was used to observe the urination,and functional magnetic resonance imaging was used to observe the brain activation.The mechanism of acupuncture at BL40 in regulating bladder function was explored by toluidine blue staining and enzyme-linked immunosorbent assay,and the mechanism was verified by stabilizing mast cells(MCs)or blocking tibial nerve.Results Deep acupuncture at BL40 significantly increased the intercontraction interval in OAB rats and enhanced the mean amplitude of low frequency fluctuation of primary motor cortex(M1),periaquaductal gray matter(PAG),and pontine micturition center(PMC).It also increased the zero-lag functional connectivity between M1 and PAG and between PAG and PMC.Shallow acupuncture at BL40 and acupuncture at non-acupoint or GB39 had no effect on these indexes.Further studies suggested that deep acupuncture at BL40 increased the number and degranulation rate of MCs as well as the contents of 5-hydroxytryptamine,substance P,and histamine in the tissues around BL40.Blocking the tibial nerve by lidocaine injection or inhibiting MC degranulation by sodium cromoglycate injection obstructed the effects of acupuncture on restoring urinary function and modulating brain activation in OAB rats.Conclusion Deep acupuncture at BL40 may be more effective for inhibiting OAB by promoting degranulation of MCs around the acupoint and stimulating tibial nerve,thereby regulating the activation of the brain area that controls the lower urinary tract. 展开更多
关键词 ACUPUNCTURE Overactive bladder Mast cell Tibial nerve Functional magnetic resonance imaging
原文传递
Effects of acupuncture needle modification on acupuncture analgesia
11
作者 Ming-zhu Sun Xin Wang +5 位作者 Ying-chen Li Yu-hang Liu Yi Yu Liu-jie Ren Wei Gu Wei Yao 《Journal of Integrative Medicine》 2025年第1期66-78,共13页
Objective The analgesic effect of acupuncture has been widely accepted.Nevertheless,the mechanism behind its analgesic effect remains elusive,thus impeding the progress of research geared toward enhancing the analgesi... Objective The analgesic effect of acupuncture has been widely accepted.Nevertheless,the mechanism behind its analgesic effect remains elusive,thus impeding the progress of research geared toward enhancing the analgesic effect of acupuncture.This paper investigated the role of acupuncture needle surface textures on acupuncture’s analgesic effect by creating four experimental acupuncture needles with different patterns of surface augmentation.Methods Four types of acupuncture needles with different surface textures(the lined needle,circle needle,sandpaper needle,and threaded needle)were designed.Additionally,the force/torque measurement system used a robot arm and mechanical sensor to measure the force on the needle during insertion and manipulation.To perform acupuncture analgesia experiments,four experimental acupuncture needles and a normal needle were inserted into the Zusanli(ST36)acupoint of rats with inflammatory pain.By comparing the force and torque and the analgesic efficacy of the different acupuncture needles,these experiments tested the role of acupuncture needle body texture on acupuncture analgesia.Results The analgesic effects of different acupuncture needle body textures varied.Specifically,the force required to penetrate the skin with the lined needle was not greater than that for the normal needle;however,the needle with inscribed circles and the sandpaper-roughened needle both required greater force for insertion.Additionally,the torque of the lined needle reached 2×10^(-4)N·m under twisting manipulation,which was four times greater the torque of a normal needle(5×10^(-5)N·m).Furthermore,the lined needle improved pain threshold and mast cell degranulation rate compared to the normal needle.Conclusion Optimizing the texture of acupuncture needles can enhance acupuncture analgesia.The texture of our experimental acupuncture needles had a significant impact on the force needed to penetrate the skin and the torque needed to manipulate the needle;it was also linked to variable analgesic effects.This study provides a theoretical basis for enhancing the analgesic efficacy of acupuncture through the modification of needles and promoting the development of acupuncture therapy. 展开更多
关键词 Acupuncture needle Acupuncture needle modification Analgesic efficacy Pain threshold Mast cell degranulation
原文传递
scRNA-seq of the intestine reveals the key role of mast cells in early gut dysfunction associated with acute pancreatitis
12
作者 Zu-Xing Wei Shi-He Jiang +4 位作者 Xiao-Yan Qi Yi-Miao Cheng Qiong Liu Xu-Yang Hou Jun He 《World Journal of Gastroenterology》 2025年第12期108-135,共28页
BACKGROUND Intestinal barrier dysfunction is a prevalent and varied manifestation of acute pancreatitis(AP).Molecular mechanisms underlying the early intestinal barrier in AP remain poorly understood.AIM To explore th... BACKGROUND Intestinal barrier dysfunction is a prevalent and varied manifestation of acute pancreatitis(AP).Molecular mechanisms underlying the early intestinal barrier in AP remain poorly understood.AIM To explore the biological processes and mechanisms of intestinal injury associated with AP,and to find potential targets for early prevention or treatment of intestinal barrier injury.METHODS This study utilized single-cell RNA sequencing of the small intestine,alongside in vitro and in vivo experiments,to examine intestinal barrier function homeostasis during the early stages of AP and explore involved biological processes and potential mechanisms.RESULTS Seventeen major cell types and 33232 cells were identified across all samples,including normal,AP1(4x caerulein injections,animals sacrificed 2 h after the last injection),and AP2(8x caerulein injections,animals sacrificed 4 h after the last injection).An average of 980 genes per cell was found in the normal intestine,compared to 927 in the AP1 intestine and 1382 in the AP2 intestine.B cells,dendritic cells,mast cells(MCs),and monocytes in AP1 and AP2 showed reduced numbers compared to the normal intestine.Enterocytes,brush cells,enteroendocrine cells,and goblet cells maintained numbers similar to the normal intestine,while cytotoxic T cells and natural killer(NK)cells increased.Enterocytes in early AP exhibited elevated programmed cell death and intestinal barrier dysfunction but retained absorption capabilities.Cytotoxic T cells and NK cells showed enhanced pathogen-fighting abilities.Activated MCs,secreted chemokine(C-C motif)ligand 5(CCL5),promoted neutrophil and macrophage infiltration and contributed to barrier dysfunction.CONCLUSION These findings enrich our understanding of biological processes and mechanisms in AP-associated intestinal injury,suggesting that CCL5 from MCs is a potential target for addressing dysfunction. 展开更多
关键词 Single-cell RNA sequencing Acute pancreatitis Mast cell CCL5 Intestinal barrier function
暂未订购
Drought limits tree growth more than greenness and reproduction:insights from five case studies in Spain
13
作者 J.Julio Camarero Alvaro Rubio-Cuadrado +5 位作者 Ester Gonzalez de Andres Cristina Valeriano Manuel Pizarro J.Bosco Imbert Yueh-Hsin Lo Juan A.Blanco 《Forest Ecosystems》 2025年第4期716-727,共12页
Droughts impact forests by influencing various processes such as canopy greenness,tree growth,and reproduction,but most studies have only examined a few of these processes.More comprehensive assessments of forest resp... Droughts impact forests by influencing various processes such as canopy greenness,tree growth,and reproduction,but most studies have only examined a few of these processes.More comprehensive assessments of forest responses to climate variability and water shortages are needed to improve forecasts of post-drought dynamics.Iberian forests are well-suited for evaluating these effects because they experience diverse climatic conditions and are dominated by various conifer and broadleaf species,many of which exhibit masting.We assessed how greenness,evaluated using the normalized difference vegetation index(NDVI),tree radial growth,and seed or cone production responded to drought in five tree species(three conifers:silver fir(Abies alba),Scots pine(Pinus sylvestris),and stone pine(Pinus pinea);two broadleaves:European beech(Fagus sylvatica)and holm oak(Quercus ilex)inhabiting sites with different aridity.We correlated these data with the standardized precipitation evapotranspiration index(SPEI)using the climate window analysis(climwin)package,which identifies the most relevant climate window.Drought constrained growth more than greenness and seed or cone production.Dry conditions led to high seed or cone production in species found in cool,moist sites(silver fir,beech,and Scots pine).We also found negative associations of cone production with summer SPEI in the drought-tolerant stone pine,which showed lagged growth-cone negative correlations.However,in the seasonally dry holm oak forests,severe droughts constrained both growth and acorn production,leading to a positive correlation between these variables.Drought impacts on greenness,growth,seed,and cone production depended on species phenology and site aridity.A negative correlation between growth and reproduction does not necessarily indicate trade-offs,as both may be influenced by similar climatic factors. 展开更多
关键词 Climate window analysis(climwin) Cone production MASTING Normalized difference vegetation index(NDVI) Tree-ring width Water shortage
在线阅读 下载PDF
Electroacupuncture ameliorates visceral hypersensitivity and negative emotions by regulating paraventricular hypothalamic nucleus and colonic corticotropin-releasing factor signaling
14
作者 Jian-Gang Xu Yi Yuan +6 位作者 Hong-Kun Ma Shun Huang Shan-Lan Zhu Tan-Ting Li Xi-Yang Wang Guo-Ming Shen Hao Wang 《World Journal of Psychiatry》 2025年第8期366-383,共18页
BACKGROUND Visceral hypersensitivity is the core pathogenesis of irritable bowel syndrome(IBS)and is often accompanied by negative emotions such as anxiety or depression.Paraventricular hypothalamic nucleus(PVN)cortic... BACKGROUND Visceral hypersensitivity is the core pathogenesis of irritable bowel syndrome(IBS)and is often accompanied by negative emotions such as anxiety or depression.Paraventricular hypothalamic nucleus(PVN)corticotropin-releasing factor(CRF)is involved in the stress-related gastrointestinal dysfunction.Electroacupuncture(EA)has unique advantages for the treatment of visceral hypersensitivity and negative emotions in IBS patients.However,the underlying mechanisms remain unclear.AIM To investigate the pathological mechanisms visceral hypersensitivity and negative emotions in IBS,as well as the effect mechanism of EA.METHODS A model of diarrhoeal IBS(IBS-D)with negative emotions was prepared by chronic restraint combined with glacial acetic acid enema.The effect of EA was verified by abdominal withdrawal reflex and open-field test.PVN CRFcolonic mast cell(MC)/transient potential receptor vanilloid type 1(TRPV1)pathway was detected by immunofluorescence,Western blot,ELISA,and toluidine blue staining.Moreover,PVN CRFergic neurons were activated or inhibited by chemogenetical technique to observe the changes of effect indicator.RESULTS In the model group,IBS-D symptoms and negative emotions were successfully induced.Notably,the combination of Baihui(GV20)with Tianshu(ST25)and Dachangshu(BL25)acupoints showed the greatest efficacy in improving the negative emotions and visceral hypersensitivity in model mice.Furthermore,we found that EA inhibited overactivated PVN CRFergic neurons and the overexpression of serum CRF,colonic CRF,CRF-receptor 1(CRFR1),mast cell tryptase(MCT),protease-activated receptor 2 and TRPV1 in model mice.Moreover,we found that activating PVN CRFergic neurons induced negative emotions and visceral hypersensitivity in normal mice;however,inhibiting PVN CRFergic neurons alleviated negative emotions and intestinal symptoms in model mice and decreased the expression of colonic CRF-R1,MCT,and TRPV1.CONCLUSION This research highlights the key role of PVN CRF-MC CRF-R1 and the downstream MC/TRPV1 pathway in the pathological process of IBS-D and the mechanism of the effect of EA. 展开更多
关键词 Visceral hypersensitivity Negative emotions Paraventricular hypothalamic nucleus Corticotropin-releasing factor Mast cell/transient potential receptor vanilloid type 1 pathway ELECTROACUPUNCTURE
暂未订购
Thymosinβ4 released by mast cells under stress conditions impairs intestinal epithelial barrier via IL22RA1/JAK1/STAT3 signaling in irritable bowel syndrome
15
作者 Yue-Shan Sun Xiao-Qin Bai +6 位作者 Kai-Di Sun Jiao Li Lei Liu Yuan-Yuan Chen Zhao-Yu Zeng Qiong Wang Yuan-Biao Guo 《World Journal of Gastroenterology》 2025年第42期171-196,共26页
Mast cells(MCs)under stress conditions contribute to the development of irritable bowel syndrome(IBS),yet their precise mechanisms in IBS remain unclear.AIM To investigate the role of MC-derived thymosinβ4(Tβ4)in st... Mast cells(MCs)under stress conditions contribute to the development of irritable bowel syndrome(IBS),yet their precise mechanisms in IBS remain unclear.AIM To investigate the role of MC-derived thymosinβ4(Tβ4)in stress-induced intestinal barrier dysfunction.METHODS The colonic mucus Tβ4 levels in IBS patients were determined and their effects on the epithelial barrier were assessed in vitro and in vivo.Specifically,rats genetically deficient in Tβ4(Tβ4^(-/-))or mice deficient in MCs(Kit^(w-sh/w-sh))were used to observe the effects of reintroducing Tβ4 or wild-type peritoneal MCs(wt-PMCs)into these animals.Additionally,the regulatory mechanism underlying Tβ4 secretion in MCs was investigated.RESULTS We demonstrated that high levels of Tβ4 in IBS mucus and intestinal MCs mediate stress-associated disruptive changes to the epithelial barrier.Moreover,Tβ4 treatment of wild-type or MC-deficient Kit^(w-sh/w-sh)mice caused a reduction in tight junction proteins and the interleukin 22 receptor A1(IL22RA1)/Reg3γcascade,but an increase in myosin light chain kinase.Furthermore,Tβ4^(-/-)rats were resistant to stress,though reintroduction of Tβ4 or wt-PMCs restored stress or corticotropin-releasing hormone(CRH)-induced barrier disturbance.Consistently,Tβ4 release from MCs was dependent on the CRH receptor 1,but not degranulation.The effect of Tβ4 was accompanied by IL22RA1/Janus kinase 1(JAK1)/signal transducer and activation of transcription 3(STAT3)pathway inhibition,suggesting a mechanism for physical and immune barrier suppression.CONCLUSION Collectively,these results suggest that Tβ4,which is abundant in IBS mucus and the secretome of MCs,plays a crucial role in the pathogenesis of IBS via IL22RA1/JAK1/STAT3 signaling,with potential implications for diagnostic and therapeutic targeting. 展开更多
关键词 Thymosinβ4 Intestinal barrier Mast cell Janus kinase 1/signal transducer and activation of transcription 3 Irritable bowel syndrome
暂未订购
Enabling Virtual Met Masts for wind energy applications through machinelearning-methods 被引量:1
16
作者 Sandra Schwegmann Janosch Faulhaber +4 位作者 Sebastian Pfaffel Zhongjie Yu Martin Dörenkämper Kristian Kersting Julia Gottschall 《Energy and AI》 2023年第1期26-42,共17页
As wind is the basis of all wind energy projects, a precise knowledge about its availability is needed. For ananalysis of the site-specific wind conditions, Virtual Meteorological Masts (VMMs) are frequently used. VMM... As wind is the basis of all wind energy projects, a precise knowledge about its availability is needed. For ananalysis of the site-specific wind conditions, Virtual Meteorological Masts (VMMs) are frequently used. VMMsmake use of site calibrated numerical data to provide precise wind estimates during all phases of a wind energyproject. Typically, numerical data are used for the long-term correlation that is required for estimating theyield of new wind farm projects. However, VMMs can also be used to fill data gaps or during the operationalphase as an additional reference data set to detect degrading sensors. The value of a VMM directly dependson its ability and precision to reproduce site-specific environmental conditions. Commonly, linear regressionis used as state of the art to correct reference data to the site-specific conditions. In this study, a frameworkof 10 different machine-learning methods is tested to investigated the benefit of more advanced methods ontwo offshore and one onshore site. We find significantly improving correlations between the VMMs and the reference data when using more advanced methods and present the most promising ones. The K-NearestNeighbors and AdaBoost regressors show the best results in our study, but Multi-Output Mixture of GaussianProcesses is also very promising. The use of more advanced regression models lead to decreased uncertainties;hence those methods should find its way into industrial applications. The recommended regression models canserve as a starting point for the development of end-user applications and services. 展开更多
关键词 Virtual Met Mast(VMM) Wind power Machine learning Reanalysis data Site assessment Weather Research and Forecasting Model(WRF) Measure-Correlate-Predict(MCP)
在线阅读 下载PDF
Mast Quadrant可扩张通道下MIS-TLIF治疗老年性腰椎管狭窄症的临床研究
17
作者 刘建建 段平国 +4 位作者 张先燎 吴青 李忠友 曾正兴 曾水平 《中国医学创新》 CAS 2024年第32期5-10,共6页
目的:对于老年性腰椎管狭窄症(LSS)患者,在Mast Quadrant可扩张通道的基础上,给予微创经椎间孔腰椎间融合术(MIS-TLIF)治疗,观察其对患者病情的改善效果。方法:2022年1月—2023年1月,选择就诊于吉安市中心人民医院的88例老年性LSS患者... 目的:对于老年性腰椎管狭窄症(LSS)患者,在Mast Quadrant可扩张通道的基础上,给予微创经椎间孔腰椎间融合术(MIS-TLIF)治疗,观察其对患者病情的改善效果。方法:2022年1月—2023年1月,选择就诊于吉安市中心人民医院的88例老年性LSS患者纳入研究,按随机数字表法将患者以1∶1的比例分成对照组和观察组,每组44例。对照组采用经椎间孔腰椎间融合术(TLIF)治疗,观察组采用Mast Quadrant可扩张通道下MIS-TLIF治疗。比较两组围手术期指标、术后并发症发生率,记录两组术前、术后6个月、术后12个月的疼痛程度[视觉模拟评分法(VAS)]和腰椎功能[日本骨科协会评估治疗(JOA)、Oswestry功能障碍指数(ODI)]并比较,记录两组术前、术后3 d的氧化应激反应指标[超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、促肾上腺皮质激素(ACTH)]并比较。结果:观察组的手术时间、术后卧床时间、住院时间均短于对照组,术中出血量、术后引流量均少于对照组,手术切口长度短于对照组(P<0.05)。两组VAS、ODI评分在术后6、12个月均明显低于术前,差异均有统计学意义(P<0.05),且观察组VAS、ODI评分在术后6个月均明显低于对照组,差异均有统计学意义(P<0.05);术后6、12个月,两组JOA评分均明显高于术前,差异均有统计学意义(P<0.05),且术后6个月,观察组JOA评分明显高于对照组,差异有统计学意义(P<0.05)。术后3 d,两组GSH-Px、SOD均明显低于术前,ACTH水平均明显高于术前,差异均有统计学意义(P<0.05);术后3 d,观察组GSH-Px、SOD均高于对照组,ACTH低于对照组(P<0.05)。两组术后并发症发生率比较,差异无统计学意义(P>0.05)。结论:Mast Quadrant可扩张通道下MIS-TLIF治疗老年性LSS相较于传统TLIF,其手术创伤小,术中应激反应轻,可有效减轻患者术后疼痛程度并改善其腰椎功能。 展开更多
关键词 老年性腰椎管狭窄症 微创经椎间孔腰椎间融合术 Mast Quadrant
暂未订购
Close relationship between mediators of inflammation and pancreatic cancer:Our experience 被引量:2
18
作者 Francesca Vescio Michele Ammendola +1 位作者 Giuseppe Currò Silvia Curcio 《World Journal of Gastroenterology》 SCIE CAS 2024年第23期2927-2930,共4页
In this editorial,we focus specifically on the mechanisms by which pancreatic inflammation affects pancreatic cancer.Cancer of the pancreas remains one of the deadliest cancer types.The highest incidence and mortality... In this editorial,we focus specifically on the mechanisms by which pancreatic inflammation affects pancreatic cancer.Cancer of the pancreas remains one of the deadliest cancer types.The highest incidence and mortality rates of pancreatic cancer are found in developed countries.Trends of pancreatic cancer incidence and mortality vary considerably worldwide.A better understanding of the etiology and identification of the risk factors is essential for the primary prevention of this disease.Pancreatic tumors are characterized by a complex microenvironment that orchestrates metabolic alterations and supports a milieu of interactions among various cell types within this niche.In this editorial,we highlight the foundational studies that have driven our understanding of these processes.In our experimental center,we have carefully studied the mechanisms of that link pancreatic inflammation and pancreatic cancer.We focused on the role of mast cells(MCs).MCs contain pro-angiogenic factors,including tryptase,that are associated with increased angiogenesis in various tumors.In this editorial,we address the role of MCs in angiogenesis in both pancreatic ductal adenocarcinoma tissue and adjacent normal tissue.The assessment includes the density of c-Kit receptor-positive MCs,the density of tryptase-positive MCs,the area of tryptasepositive MCs,and angiogenesis in terms of microvascularization density. 展开更多
关键词 Mast cells C-Kit receptor TRYPTASE Angiogenesis Microvascular density Endothelial area Pancreatic tumor tissue Adjacent normal tissue
暂未订购
Nonlinear characteristics of torsional stiffness of a coilable mast with triangular section 被引量:1
19
作者 Yu LIU Liang SUN +3 位作者 Hai HUANG Shenyan CHEN Weipeng LI Xurui ZHAO 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2024年第10期313-324,共12页
With numerous applications coilable masts in high-precision astronomical observations,such as X-ray source observations,it is important to investigate mast stiffness.To date,there have been many studies on the bending... With numerous applications coilable masts in high-precision astronomical observations,such as X-ray source observations,it is important to investigate mast stiffness.To date,there have been many studies on the bending stiffness of coilable masts,but few studies on their torsional stiffness,especially regarding the nonlinear characteristics of torsional stiffness of coilable masts under large torsional deformation.In this paper,a nonlinear analysis method is presented to examine the torsional stiffness of coilable masts with triangular sections.Based on the second-order bending buckling hypothesis of battens under large torsion deformation,the nonlinear relationship between torsional torque and torsional angle is obtained by analyzing torsional deformation and force of coilable masts.This method is used to analyze the torsional stiffness nonlinearity of a certain type of coilable mast which will be used in a practical application in the future and the results are verified by simulation and testing.The comparison results show that the error is within the acceptable range,which proves the effectiveness of the proposed method. 展开更多
关键词 Coilable mast Torsion testing Torsional stiffness nonlinearity Torsional deformation Torsion simulation
原文传递
Mast cell degranulation-triggered by SARS-CoV-2 induces tracheal-bronchial epithelial inflammation and injury 被引量:1
20
作者 Jian-Bo Cao Shu-Tong Zhu +7 位作者 Xiao-Shan Huang Xing-Yuan Wang Meng-Li Wu Xin Li Feng-Liang Liu Ling Chen Yong-Tang Zheng Jian-Hua Wang 《Virologica Sinica》 SCIE CAS CSCD 2024年第2期309-318,共10页
SARS-CoV-2 infection-induced hyper-inflammation is a key pathogenic factor of COVID-19.Our research,along with others',has demonstrated that mast cells(MCs)play a vital role in the initiation of hyper-inflammation... SARS-CoV-2 infection-induced hyper-inflammation is a key pathogenic factor of COVID-19.Our research,along with others',has demonstrated that mast cells(MCs)play a vital role in the initiation of hyper-inflammation caused by SARS-CoV-2.In previous study,we observed that SARS-CoV-2 infection induced the accumulation of MCs in the peri-bronchus and bronchioalveolar-duct junction in humanized mice.Additionally,we found that MC degranulation triggered by the spike protein resulted in inflammation in alveolar epithelial cells and capillary endothelial cells,leading to subsequent lung injury.The trachea and bronchus are the routes for SARS-CoV-2 transmission after virus inhalation,and inflammation in these regions could promote viral spread.MCs are widely distributed throughout the respiratory tract.Thus,in this study,we investigated the role of MCs and their degranulation in the development of inflammation in tracheal-bronchial epithelium.Histological analyses showed the accumulation and degranulation of MCs in the peri-trachea of humanized mice infected with SARS-CoV-2.MC degranulation caused lesions in trachea,and the formation of papillary hyperplasia was observed.Through transcriptome analysis in bronchial epithelial cells,we found that MC degranulation significantly altered multiple cellular signaling,particularly,leading to upregulated immune responses and inflammation.The administration of ebastine or loratadine effectively suppressed the induction of inflammatory factors in bronchial epithelial cells and alleviated tracheal injury in mice.Taken together,our findings confirm the essential role of MC degranulation in SARS-CoV-2-induced hyper-inflammation and the subsequent tissue lesions.Furthermore,our results support the use of ebastine or loratadine to inhibit SARS-CoV-2-triggered degranulation,thereby preventing tissue damage caused by hyper-inflammation. 展开更多
关键词 SARS-CoV-2 Mast cell(MC) Bronchial epithelial cell INFLAMMATION Tracheal injury
原文传递
上一页 1 2 15 下一页 到第
使用帮助 返回顶部