期刊文献+
共找到162篇文章
< 1 2 9 >
每页显示 20 50 100
RPL-Based IoT Networks under Decreased Rank Attack:Performance Analysis in Static and Mobile Environments
1
作者 Amal Hkiri Mouna Karmani +3 位作者 Omar Ben Bahri Ahmed Mohammed Murayr Fawaz Hassan Alasmari Mohsen Machhout 《Computers, Materials & Continua》 SCIE EI 2024年第1期227-247,共21页
The RPL(IPv6 Routing Protocol for Low-Power and Lossy Networks)protocol is essential for efficient communi-cation within the Internet of Things(IoT)ecosystem.Despite its significance,RPL’s susceptibility to attacks r... The RPL(IPv6 Routing Protocol for Low-Power and Lossy Networks)protocol is essential for efficient communi-cation within the Internet of Things(IoT)ecosystem.Despite its significance,RPL’s susceptibility to attacks remains a concern.This paper presents a comprehensive simulation-based analysis of the RPL protocol’s vulnerability to the decreased rank attack in both static andmobilenetwork environments.We employ the Random Direction Mobility Model(RDM)for mobile scenarios within the Cooja simulator.Our systematic evaluation focuses on critical performance metrics,including Packet Delivery Ratio(PDR),Average End to End Delay(AE2ED),throughput,Expected Transmission Count(ETX),and Average Power Consumption(APC).Our findings illuminate the disruptive impact of this attack on the routing hierarchy,resulting in decreased PDR and throughput,increased AE2ED,ETX,and APC.These results underscore the urgent need for robust security measures to protect RPL-based IoT networks.Furthermore,our study emphasizes the exacerbated impact of the attack in mobile scenarios,highlighting the evolving security requirements of IoT networks. 展开更多
关键词 RPL decreased rank attacks MOBILITY random direction model
下载PDF
基于Mean Decrease Impurity改进XGBoost算法 被引量:2
2
作者 杜俊杰 朱永忠 丁根宏 《信息技术》 2019年第9期1-4,共4页
针对XGBoost算法在处理高维数据集分类准确率和效率下降的情况,文中提出一种基于mean decrease impurity算法改进的XGBoost算法;并设计频数算法解决mean decrease impurity算法对特征重要度排名的随机性。实验结果表明,本方法预测效率... 针对XGBoost算法在处理高维数据集分类准确率和效率下降的情况,文中提出一种基于mean decrease impurity算法改进的XGBoost算法;并设计频数算法解决mean decrease impurity算法对特征重要度排名的随机性。实验结果表明,本方法预测效率以及准确率要优于未改进XGBoost算法,同时mean decrease impurity算法也优于基于方差算法。因此,文中所提出的分类方法具有更高的准确率和效率。 展开更多
关键词 XGBoost 高维数据 mean decrease IMPURITY 集成学习
下载PDF
Decreased osteogenesis of adult mesenchymal stem cel s by reactive oxygen species under cyclic stretch: a possible mechanism of age related osteoporosis 被引量:16
3
作者 Jiali Tan Xin Xu +4 位作者 Zhongchun Tong Jiong lin Qiujun Yu Yao Lin Wei Kuang 《Bone Research》 SCIE CAS CSCD 2015年第1期46-51,共6页
Age related defect of the osteogenic differentiation of mesenchymal stem cells(MSCs) plays a key role in osteoporosis. Mechanical loading is one of the most important physical stimuli for osteoblast differentiation.... Age related defect of the osteogenic differentiation of mesenchymal stem cells(MSCs) plays a key role in osteoporosis. Mechanical loading is one of the most important physical stimuli for osteoblast differentiation.Here, we compared the osteogenic potential of MSCs from young and adult rats under three rounds of 2 h of cyclic stretch of 2.5% elongation at 1 Hz on 3 consecutive days. Cyclic stretch induced a significant osteogenic differentiation of MSCs from young rats, while a compromised osteogenesis in MSCs from the adult rats.Accordingly, there were much more reactive oxygen species(ROS) production in adult MSCs under cyclic stretch compared to young MSCs. Moreover, ROS scavenger N-acetylcysteine rescued the osteogenic differentiation of adult MSCs under cyclic stretch. Gene expression analysis revealed that superoxide dismutase 1(SOD1) was significantly downregulated in those MSCs from adult rats. In summary, our data suggest that reduced SOD1 may result in excessive ROS production in adult MSCs under cyclic stretch, and thus manipulation of the MSCs from the adult donors with antioxidant would improve their osteogenic ability. 展开更多
关键词 MSCs decreased osteogenesis of adult mesenchymal stem cel s by reactive oxygen species under cyclic stretch ROS STEM
下载PDF
Circulating Neutrophil Counts Decrease in Response to Mitigated Air Quality in Stable COPD Patients 被引量:3
4
作者 ZHANG Zi Li WANG Jian +4 位作者 LIU Fen DING Ming Jing LIU Fei CHEN Si Fan LU Wen Ju 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2018年第1期66-71,共6页
This three-year study, based on the Guangzhou Institute of Respiratory Disease (GRID), chronic obstructive pulmonary disease (COPD) Biobank, was conducted in 36 COPD patients to estimate whether changes in levels ... This three-year study, based on the Guangzhou Institute of Respiratory Disease (GRID), chronic obstructive pulmonary disease (COPD) Biobank, was conducted in 36 COPD patients to estimate whether changes in levels of leukocytes, erythrocytes, hemoglobin, and platelets were related to changes in air pollutant concentration. Daily NO2 levels exhibited significant differences between baseline years and the 2010 Asian Game period. We observed significant reductions in leukocyte and neutrophils counts levels, by 15.51% and 23.01%, from pre-Asian Games to during-Asian Games, respectively. In the post-Asian Game period, most pollutants approximated pre-Asian Game period levels, and similar effects were demonstrated in leukocyte and neutrophil counts. For both items, we identified significant increases resulting from elevated NO2 at lag days 0-2/5-6. We concluded that reductions in pollutants during the intervention period were associated with inactivation of hematological events in COPD. 展开更多
关键词 Circulating Neutrophil Counts decrease Mitigated Air Quality in Stable COPD Patients
下载PDF
Retardation of an IGG gas flow along a mine drift due to condensation and temperature decrease 被引量:1
5
作者 Rickard Hansen 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2019年第6期831-839,共9页
The progress of the GAG gas flow in a conveyor drift is investigated.The output of a calculation model is evaluated and compared with experimental results from full-scale inertisation experiments.Expressions presentin... The progress of the GAG gas flow in a conveyor drift is investigated.The output of a calculation model is evaluated and compared with experimental results from full-scale inertisation experiments.Expressions presenting the fastest and most extensive condensation of water resulted in well fitted arrival times of the GAG gas front.A common denominator for the two sets of expressions is that the type of flow is considered and thus better fitted to the actual flow situation.The model was further refined to include the surface roughness factor in the condensation calculations,which resulted in time lengths even closer to the measured time length.The measured rapid temperature increase at certain positions along the conveyor drift was found to fit well with the calculated GAG gas front arrival at the corresponding positions.The magnitude of the GAG flow was found to have a large impact on the arrival time of the GAG gas front.Knowing and understanding the GAG gas behaviour would increase the likelihood of successful inertisation of all or part of a mine. 展开更多
关键词 GAG Inert GAS CONDENSATION Temperature decrease GAS velocity MINE DRIFT
下载PDF
Magnetization-Enhanced Dislocation Motion and Decreased Yield Strength of 60Fe40Ni Alloy 被引量:1
6
作者 Hongqi LI, Yanbin WANG and Wuyang CHU Dept. of Materials Physics & Chemistry, University of Science and Technology Beijing, Beijing 100083, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第4期457-459,共3页
Using a special constant deflection device, the changes in dislocation configuration ahead of a loaded crack tip for 60Fe40Ni alloy. before and after magnetization in a magnetic field, have been studied in TEM. The re... Using a special constant deflection device, the changes in dislocation configuration ahead of a loaded crack tip for 60Fe40Ni alloy. before and after magnetization in a magnetic field, have been studied in TEM. The results showed that the magnetization for 60Fe40Ni alloy could enhance dislocation emission, multiplication and motion. Also, the mechanical properties of 60Fe40Ni alloy, in air and in the magnetic field respectively have been investigated using the slow strain rate tension. And the results indicated that magnetization could make the yield strength corresponding to decrease by 26 percent, but did not influence the ultimate tensile strength and the fracture strain, which showed that magnetization could enhance plastic deformation. 展开更多
关键词 FE Magnetization-Enhanced Dislocation Motion and decreased Yield Strength of 60Fe40Ni Alloy NI
下载PDF
A new model describing Forbush Decreases at Mars: combining the heliospheric modulation and the atmospheric influence 被引量:1
7
作者 Jingnan Guo Robert FWimmer-Schweingruber +2 位作者 Mateja Dumbović Bernd Heber YuMing Wang 《Earth and Planetary Physics》 CSCD 2020年第1期62-72,共11页
Forbush decreases are depressions in the galactic cosmic rays (GCRs) that are caused primarily by modulations of interplanetary coronal mass ejections (ICMEs) but also occasionally by stream/corotating interaction reg... Forbush decreases are depressions in the galactic cosmic rays (GCRs) that are caused primarily by modulations of interplanetary coronal mass ejections (ICMEs) but also occasionally by stream/corotating interaction regions (SIRs/CIRs). Forbush decreases have been studied extensively using neutron monitors at Earth;recently, for the first time, they have been measured on the surface of another planet, Mars, by the Radiation Assessment Detector (RAD) on board the Mars Science Laboratory’s (MSL) rover Curiosity. The modulation of GCR particles by heliospheric transients in space is energy-dependent;afterwards, these particles interact with the Martian atmosphere, the interaction process depending on particle type and energy. In order to use ground-measured Forbush decreases to study the space weather environment near Mars, it is important to understand and quantify the energy-dependent modulation of the GCR particles by not only the pass-by heliospheric disturbances but also by the Martian atmosphere. Accordingly, this study presents a model that quantifies both at the Martian surface and in the interplanetary space near Mars the amplitudes of Forbush decreases at Mars during the pass-by of an ICME/SIR by combining the heliospheric modulation of GCRs with the atmospheric modification of such modulated GCR spectra. The modeled results are in good agreement with measurements of Forbush decreases caused by ICMEs/SIRs based on data collected by MSL on the surface of Mars and by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft in orbit. Our model and these findings support the validity of both the Forbush decrease description and Martian atmospheric transport models. 展开更多
关键词 ICME and Forbush decreases space weather at Mars Mars:atmosphere GCR radiation
下载PDF
Decrease of Matrix Plasticity Promotes Fibroblast Activation in Fibrosis
8
作者 Yuanbo Jia Yanzhong Wang +8 位作者 Lele Niu Hang Zhang Jin Tian Dengfeng Gao Xiaohui Zhang Tian Jian Lu Jin Qian Guoyou Huang Feng Xu 《医用生物力学》 EI CAS CSCD 北大核心 2019年第A01期126-127,共2页
This work identified the important role of matrix mechanical plasticity in mediating fibroblast activation.Many existing studies have highlighted the important effects of biochemical cues(e.g.,transforming growth fact... This work identified the important role of matrix mechanical plasticity in mediating fibroblast activation.Many existing studies have highlighted the important effects of biochemical cues(e.g.,transforming growth factor-β1)and mechanicalstiffness on fibroblast activation.Our results indicated that self-assembled collagen hydrogels showed high plasticity and in which fibroblasts remain undifferentiated.However,when we decreased the plasticity of collagen hydrogels by increasing covalent crosslinking,fibroblasts showed a significant fibrotic response as reflected by the increasedα-SMA expression.Since the material systems we constructed have low and the same initial modulus,this process is stiffness independent.Although it has been reported that covalently crosslinked hydrogels are more difficult to degrade and matrix degradability has an important impact on cell behaviors,no significant changes of fibroblast activation were observed when proteases were broadly inhibited in our experiments.Importantly,the hydrogels we constructed showed similar plastic behaviors under creep and recovery tests compared to native normal and fibrotic tissues.These highlight the importance of matrix plasticity in mimicking the mechanical microenvironment of native fibrotic tissues.Mechanistically,we found that the enhanced fibroblast activation in low plastic matrix is mediated through integrin-actin pathway and nuclear localization of YAP.In high plastic collagen,matrix cannot provide effective resistance to actin contraction because of the rupture of weak crosslinks and the slippage of local fibers.On the contrary,in low plastic collagen,deformation energy can be stored in the network due to the existence of strong covalent crosslinks,thus enabling the build-up of cell traction and the formation of a robust cell-matrix interaction.Experiments of inhibiting or promoting cytoskeletal contractility and CGMD simulation both verified the above points.Our results clarify plasticity changes on the development of fibrotic diseases and highlight plasticity as an important mechanical cue in understanding cell-matrix interactions. 展开更多
关键词 decrease MATRIX PLASTICITY PROMOTES FIBROBLAST Activation FIBROSIS MATRIX
下载PDF
THE INFLUENCE OF THE COSMIC RAY FORBUSH DECREASE ON THE LOW IONOSPHERE IN THE POLAR REGION
9
作者 宗秋刚 叶宗海 +1 位作者 薛丙森 叶晓蔚 《Chinese Journal of Polar Science》 1993年第1期1-11,共11页
Used the ionization theory of the cosmic ray charged particles in the polar ionosphere, the influence of the cosmic ray Forbush decrease on the low ionosphere in the polar region is studied in this paper. The relation... Used the ionization theory of the cosmic ray charged particles in the polar ionosphere, the influence of the cosmic ray Forbush decrease on the low ionosphere in the polar region is studied in this paper. The relationship between the Forbush decrease and the cosmic noise absorption during the polar night is analysed based on the data recorded by a Riometer at Antarctic Zhongshan Station (69° 22'24'S, 76°22'40'E). The relation of between the cosmic ray Forbush decrease and the cosmic noise absorption is well interpreted by means of the ionizaiotn theory. 展开更多
关键词 cosmic ray Forbush decrease precipitation particles polar ionosphere cosmic noise absorption
下载PDF
Promoting Poverty Alleviation through the Project of Linkage of Urban Construction Land Increase with Rural Construction Land Decrease——A Case Study of Binchuan County in Yunnan Province
10
作者 Jing LIU Zisheng YANG 《Asian Agricultural Research》 2018年第3期51-55,65,共6页
The policy of linkage of urban construction land increase with rural construction land decrease is an important task for poverty alleviation. It not only promotes the intensive use of land and the coordinated developm... The policy of linkage of urban construction land increase with rural construction land decrease is an important task for poverty alleviation. It not only promotes the intensive use of land and the coordinated development of urban and rural areas,but also plays an essential role in poverty alleviation development and the relocation of poverty alleviation. It provides a strong guarantee for winning the project of poverty alleviation. Taking the project of linkage of urban construction land increase with rural construction land decrease in Binchuan County in Yunnan Province,combined with the current situation of poverty alleviation and relocation in Binchuan County,the implementation of related policies of linkage of urban construction land increase with rural construction land decrease,and path of relocation poverty alleviation,this paper introduced problems in the implementation of policies of linkage of urban construction land increase with rural construction land decrease in Binchuan County,and came up with recommendations for the project of poverty alleviation through linkage of urban construction land increase with rural construction land decrease. 展开更多
关键词 Linkage of urban construction land increase with rural construction land decrease Tough battle against poverty Relocation of poverty alleviation Recommendations
下载PDF
IMPAIRED AUTOLOGOUS MIXED LYMPHOCYTE REACTION CORRELATED WITH DECREASED EXPRESSION OF HLA-Ⅱ ANTIGENS ON MONOCYTES IN PATIENTS WITH MYELOID LEUKEMIA
11
作者 龚非力 H.Grosse Wilde 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 1991年第2期14-20,共7页
The proliferative response of T-cells to autolo-gous non-T-cells is referred to as the autologous mixed lymphocyte reaction (AMLR). Recent studies have suggested that AMLR represents a mechanism of immune regulation i... The proliferative response of T-cells to autolo-gous non-T-cells is referred to as the autologous mixed lymphocyte reaction (AMLR). Recent studies have suggested that AMLR represents a mechanism of immune regulation in vivo. We investigated AMLR in patients with acute- and chronic myeloid leukemia (AML and CML). AMLR was found to be significantly depressed (P<0.001) in AML patients (n=17, cpm=532±95) and CML patients (n=13, cpm=688±99) when compared with that of their healthy HLA-identical siblings serving as controls (n=17, cpm=4152±619 and n=13 cpm=4086±421, respectively). In order to understand the cellular basis of the defective AMLR in patients with AML end CML, we performed mitogen-treated T-cell cultures analysis of T-cell subsets and HLA-Ⅱ antigen detection on monocytes. The results indicated that the defect of AMLR in patients resided at the stimulator monocyte level rather than at the responder T-cell level. Enumeration of monocytes reactive with monoclonal antibody Tu22, which recognizes determinants of HLA-DQ, demonstrated that ML patients had a significantly decreased (P<0.091) number of circulating Tu22+ monocytes when compared with normal controls. These studies suggest that a deficiency of HLA-DQ+ monocytes contributes to the depression of AMLR in ML and possibly underlies the abnormalities of immune response present in this disease. 展开更多
关键词 AMLR IMPAIRED AUTOLOGOUS MIXED LYMPHOCYTE REACTION CORRELATED WITH decreaseD EXPRESSION OF HLA ANTIGENS ON MONOCYTES IN PATIENTS WITH MYELOID LEUKEMIA
下载PDF
Rules and Characteristics of TCM Treatment Prescriptions for Patients with Decreased Ovarian Reserve
12
作者 Ying WANG Guoqiang LIANG Xuanyi CHEN 《Medicinal Plant》 CAS 2022年第4期50-52,共3页
[Objectives]To analyze the characteristics and rules of traditional Chinese medicine(TCM)in the treatment of decreased ovarian reserve(DOR)in Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine.[M... [Objectives]To analyze the characteristics and rules of traditional Chinese medicine(TCM)in the treatment of decreased ovarian reserve(DOR)in Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine.[Methods]A total of 107 patients with DOR in Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine were selected for sorting,and the usage,classification,nature,taste and meridian homing of the used drugs were statistically analyzed.[Results]A total of 107 patients were included in this stud and a total of 189 flavors of TCM are used.The total frequency of drugs was 4345 times,and a total of 535 prescriptions were issued.The top five frequency of drug use were 2261 times(50.04%)of Paeoniae Radix Alba(Cynanchum otophyllum Schneid.),2037 times(46.88%)of Corni Fructus(Cornus officinalis Sieb.et Zucc.),1818 times(41.84%)of Rehmanniae Radix Praeparata[Rehmannia glutinosa(Gaertn.)Libosch EX Fisch.et Mey.],1610 times(37.05%)of Guiban[Chinemys reevesii(Gray)],and 1303 times(29.99%)of Uncariae Ramulus Cum Uncis(Uncariar hynchophylla Miq.ex Havil.).Kidney deficiency syndrome accounted for the largest proportion at 51.40%,and the use frequency of tonic drugs accounted for the highest at 50.64%;heat-clearing drugs and qi and blood-boosting drugs separately accounted for 19.24%and 17.39%;the top 3 medicinal tastes are sweet(52.02%),pungent(20.71%)and bitter(20.32%);medicinal properties are ranked as warm(60.54%),cold(24.16%),hot(8.72%)and cool(6.49%);the main meridians are spleen,lung,liver,stomach and kidney.[Conclusions]The basic pathogenesis of DOR is deficiency of qi and blood,mainly due to dysfunction of the spleen,lung,liver,liver,stomach and other organs,and kidney deficiency and spleen deficiency are more common. 展开更多
关键词 decreased ovarian reserve(DOR) Traditional Chinese Medicine(TCM) Medication analysis PATHOGENESIS
下载PDF
Macrophage migration inhibitory factor decreased T-type Ca^(2+) channel current through activating Src
13
作者 RAO Fang,DENG Chun-yu,WU Shu-lin,YU Xi-yong,XIAO Ding-zhang,HUANG Wei,KUANG Su-juan,LIN Qiu-xiong, ShanZhi-xin (Department of Cardiology,Guangdong Cardiovascular Institute, Guangzhou 510100,China) 《岭南心血管病杂志》 2011年第S1期196-196,共1页
Aims T-type Ca<sup>2+</sup> current(I<sub>CaT</sub>)plays an important role in the pathogenesis of atrial fibrillation(AF).The present study sought to investigate the role of Macrophage migra... Aims T-type Ca<sup>2+</sup> current(I<sub>CaT</sub>)plays an important role in the pathogenesis of atrial fibrillation(AF).The present study sought to investigate the role of Macrophage migration inhibitory factor(MIF),a pleiotropic cytokine,in the regulation of T-type Ca<sup>2+</sup> channel in atrium myocytes.Methods We used whole-cell voltage-clamp technique and biochemical assays to study the regulation and expression of I<sub>Ca</sub>,T in mouse atrium myocytes(HL-1 cells).Results Serum MIF concentrations was slightly increased in patients with AF compared to sinus rhythm(SR) controls.In cultured HL-1 cells, significant amounts of MIF were produced in response to hydrogen peroxide(H<sub>2</sub>O<sub>2</sub>),but not AngiotensinⅡ(AngⅡ). Mouse recombinant MIF(rMIF)(20 or 40 nM,24 h) suppressed peak ICa,T by-38%and-60%in a concentration-dependent manner,impaired the voltage-dependent activation of I<sub>Ca</sub>,T,and down-regulated of TCC alG mRNA.Src inhibitors genistein and PPl significantly enhanced ICaT.The depression of ICa,T induced by rMIF could be reversed by genistein and PP1.Conclusions MIFis involved in the pathogenesis of AF,probably by decreasing ICa,T through impairment of the channel function and activation of c-Src kinases in atrium myocytes. 展开更多
关键词 type channel current through activating Src MIF Macrophage migration inhibitory factor decreased T-type Ca
下载PDF
Bilateral Iris Coloboma Revealed by a Decreased Vision: About the First Case in Togo Observed in Kara University Teaching Hospital
14
作者 Kokou Messan Amedome Codjo Rodrigue Abel Assavédo +4 位作者 Yao Ako Patrick Mensah Kossi Dzidzinyo Kokou Vonor Koffi Didier Ayéna Komi Balo 《Open Journal of Ophthalmology》 2021年第4期249-252,共4页
<strong>Background:</strong> Ocular coloboma is the product of an error in the fetal fissure closure, normally occurring between the fifth and sixth weeks of gestation <a href="#R1" target=&qu... <strong>Background:</strong> Ocular coloboma is the product of an error in the fetal fissure closure, normally occurring between the fifth and sixth weeks of gestation <a href="#R1" target="_blank">[1]</a>. It may involve the cornea, iris, zonula, ciliary body, choroid, retina and optic nerve. The incidence of this syndrome is 0.7 per 10,000 live-births <a href="#R1" target="_blank">[1]</a>. The aim of this observation is to present the first case of bilateral coloboma of the iris <a href="#R1" target="_blank">[1]</a>. This case was associated with an ametropia causing a decrease in visual acuity. <strong>Case Presentation:</strong> This was a clinical observation concerning a young 12-year-old patient who consulted for blurring of vision which had progressed for approximately 2 years. The ophthalmologic examination revealed an ametropia with a bilateral notch of the pupillary rim suggesting a bilateral coloboma. There was no association with another coloboma such as chorioretinal coloboma which is quite common and is accompanied frequently by visual symptoms. <strong>Conclusion:</strong> A visual impairment of the child can indicate ametropia. However, other congenital anomalies can be discovered as was the case in this clinical observation. 展开更多
关键词 COLOBOMA IRIS decreased Vision Kara TOGO
下载PDF
Overview of the Mechanism of Acupuncture and Moxibustion treatment of Decreased Ovarian Reserve
15
作者 Mao Lin Tongsheng Su 《Journal of Clinical and Nursing Research》 2021年第4期100-102,共3页
Decreased ovarian reserve is one of the hot topics in current research.This article discusses the mechanism of acupuncture treatment of decreased ovarian reserve through the current acupuncture and moxibustion experim... Decreased ovarian reserve is one of the hot topics in current research.This article discusses the mechanism of acupuncture treatment of decreased ovarian reserve through the current acupuncture and moxibustion experimental research on the endocrine system and immune system. 展开更多
关键词 ACUPUNCTURE decreased ovarian reserve MECHANISM OVERVIEW
下载PDF
The preparation of nanoscale composite of polyurethane to decrease platelet deposition on the surface
16
《Chinese Journal of Biomedical Engineering(English Edition)》 2001年第4期194-196,共3页
关键词 The preparation of nanoscale composite of polyurethane to decrease platelet deposition on the surface
下载PDF
Rapid decrease in Antarctic sea ice in recent years 被引量:1
17
作者 Guanghua Hao Hui Shen +1 位作者 Yongming Sun Chunhua Li 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第7期119-128,共10页
A 41-year Antarctic sea ice concentration(SIC)dataset derived from satellite passive microwave radiometers during the period of 1979–2019 has been used to analyze sea ice changes in recent decades.The trends of SIC a... A 41-year Antarctic sea ice concentration(SIC)dataset derived from satellite passive microwave radiometers during the period of 1979–2019 has been used to analyze sea ice changes in recent decades.The trends of SIC and sea ice extent(SIE)are calculated during the periods of 1979–2019,1979–2013,and 2014–2019.The trends show regionally dependent features.The SIC shows an increasing trend in most of the regions except the Bellingshausen Sea and Amundsen Sea(BA)during 1979–2019 and 1979–2013.The SIE trend shows a decreasing or decelerating trend in the period of 1979–2019((6835±2210)km^(2)/a)compared with the 1979–2013 period((18600±2203)km^(2)/a).In recent years(2014–2019),the SIC and SIE have exhibited decreasing trends(–(34567±3521)km^(2)/month),especially in the Weddell Sea(WS)and Ross Sea(RS)during summer and autumn.The trends are related to regionally dependent causes.The analyses show that the SIC and SIE decreased in response to the warming trend of 2 m air temperature(T_(a-2m))and have exhibited a good relationship with T_(a-2m) in summer and autumn in recent years.The sea ice decrease in the Antarctic is mainly caused by increases in absorbed energy and southward energy transportation in recent years,such as the increase in gained solar radiation and moist static energy from the south,which demonstrate notable regional characteristics.In the WS region,the local positive feedback from the additional absorbed solar radiation,resulting in warmer air and reduced sea ice,is the main reason for the sea ice decrease in recent years.The increase in southward energy transport has also favored a decrease in sea ice.In the RS region,the increase in southward-transported moist static energy has contributed to the decrease in sea ice,and the increases in cloud cover and longwave radiation have prevented sea ice growth. 展开更多
关键词 sea ice ANTARCTIC DECREASING ATMOSPHERE
下载PDF
Optimal Decreased Torque Gain Control for Maximizing Wind Energy Extraction Under Varying Wind Speed
18
作者 Liansong Guo Minghui Yin +2 位作者 Chenxiao Cai Yunyun Xie Yun Zou 《Journal of Modern Power Systems and Clean Energy》 SCIE EI CSCD 2023年第3期853-862,共10页
Optimal torque(OT)control is a widely used method for maximum power point tracking(MPPT)due to its simplicity.In order to overcome the adverse impacts of turbulent wind speed variations on MPPT,in several methods,modi... Optimal torque(OT)control is a widely used method for maximum power point tracking(MPPT)due to its simplicity.In order to overcome the adverse impacts of turbulent wind speed variations on MPPT,in several methods,modification factors have been proposed to dynamically modify the ideal power curve for OT control.However,this paper finds that the update cycles used in existing methods to adjust power curve modification factors are very long and hence these factors are difficult to be updated in a timely manner along with the wind speed variations.This thereby may deteriorate the effectiveness of wind energy extraction.Therefore,an optimal decreased torque gain(DTG)control method is proposed in this paper.Based on the persistence method,an offline mapping from the wind speed and rotor speed to optimal modification factors is established via optimal control theory.The power curve can be periodically modified online through the mapping relationship.In this method,the update cycles for these power curve modification factors are shortened from tens of minutes to seconds.The simulations and experiments show that the proposed method is more efficient than others in terms of energy extraction under varying wind speeds,especially for turbulent wind cases. 展开更多
关键词 decreased torque gain(DTG) maximum power point tracking(MPPT) offline mapping optimal control persistence method
原文传递
Decrease in DNA methylation 1(DDM1) is required for the formation of ~mCHH islands in maize 被引量:2
19
作者 Jin Cheng Long Ai Ai Xia +4 位作者 Jing Han Liu Ju Li Jing Ya Zhong Wang Chuang Ye Qi Yan He 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2019年第6期749-764,共16页
DNA methylation plays a crucial role in suppressing mobilization of transposable elements and regulation of gene expression. A number of studies have indicated that DNA methylation pathways and patterns exhibit distin... DNA methylation plays a crucial role in suppressing mobilization of transposable elements and regulation of gene expression. A number of studies have indicated that DNA methylation pathways and patterns exhibit distinct properties in different species, including Arabidopsis, rice, and maize.Here, we characterized the function of DDM1 in regulating genome-wide DNA methylation in maize. Two homologs of Zm DDM1 are abundantly expressed in the embryo and their simultaneous disruption caused embryo lethality with abnormalities in cell proliferation from the early stage of kernel development. We establish that Zm DDM1 is critical for DNA methylation, at CHG sites, and to a lesser extent at CG sites, inheterochromatic regions, and unexpectedly, it is required for the formation ofmCHH islands. In addition, Zm DDM1 is indispensable for the presence of 24-nt si RNA, suggesting its involvement in the Rd DM pathway. Our results provide novel insight into the role of Zm DDM1 in regulating the formation of mCHH islands, via the Rd DM pathway maize, suggesting that,in comparison to Arabidopsis, maize may have adopted distinct mechanisms for regulating ~mCHH. 展开更多
关键词 decrease in DNA METHYLATION suppressing MOBILIZATION pathway MAIZE
原文传递
Moxibustion alleviates decreased ovarian reserve in rats by restoring the PI3K/AKT signaling pathway 被引量:2
20
作者 Hong-xiao Li Ling Shi +7 位作者 Shang-jie Liang Chen-chen Fang Qian-qian Xu Ge Lu Qian Wang Jie Cheng Jie Shen Mei-hong Shen 《Journal of Integrative Medicine》 SCIE CAS CSCD 2022年第2期163-172,共10页
Objective:Moxibustion,a common therapy in traditional Chinese medicine,has potential benefits for treating decreased ovarian reserve(DOR).The present study investigates the protective effect of moxibustion in a rat mo... Objective:Moxibustion,a common therapy in traditional Chinese medicine,has potential benefits for treating decreased ovarian reserve(DOR).The present study investigates the protective effect of moxibustion in a rat model of DOR and explores the possible mechanisms.Methods:Sixty-four female Sprague-Dawley rats were randomly divided into four groups:control,DOR,moxibustion(MOX),and hormone replacement therapy(HRT).The DOR rat model was established by intragastric administration of 50 mg/kg Tripterygium glycoside suspension(TGS),once daily for 14 days.MOX and HRT treatments were given from the day TGS administration was initiated.The ovarian reserve function was evaluated by monitoring the estrus cycle,morphological changes in ovaries,levels of serum estradiol(E2),follicle-stimulating hormone(FSH),luteinizing hormone(LH),and anti-Mullerian hormone(AMH),pregnancy rate and embryo numbers.Terminal-deoxynucleotidyl transferase-mediated nickend-labeling staining was used to identify ovarian granulosa cell apoptosis,while the protein and m RNA expressions of Bax,B-cell lymphoma-2(Bcl-2),phosphatidylinositol 3-kinase(PI3 K)and protein kinase B(AKT)in ovarian tissues were examined by immunohistochemistry,Western blot and quantitative reverse transcription-polymerase chain reaction.Results:Compared with the DOR group,MOX improved the disordered estrous cycle,promoted follicular growth,reduced the number of atresia follicles,increased the concentrations of serum E2 and AMH,and decreased serum FSH and LH concentrations.More importantly,the pregnancy rate and embryo numbers in DOR rats were both upregulated in the MOX treatment group,compared to the untreated DOR model.Further,we found that the MOX group had reduced apoptosis of ovarian granulosa cells,increased Bcl-2 expression and reduced expression of Bax.Furthermore,the PI3 K/AKT signaling pathway was triggered by the moxibustion treatment.Conclusion:Moxibustion improved ovarian function and suppressed apoptosis of ovarian granulosa cells in a rat model of DOR induced by TGS,and the mechanism may involve the PI3 K/AKT signaling pathway. 展开更多
关键词 decreased ovarian reserve MOXIBUSTION Phosphatidylinositol 3-kinase Protein kinase B APOPTOSIS INFERTILITY
原文传递
上一页 1 2 9 下一页 到第
使用帮助 返回顶部