Lipid rafts participate in aberrant degradative autophagic-lysosomal pathway of amyloid-beta peptide in Alzheimer's disease

Amyloid-beta peptide is the main component of amyloid plaques, which are found in Alzhei- mer＇s disease. The generation and deposition of amyloid-beta is one of the crucial factors for the onset and progression of Alzheimer＇s disease. Lipid rafts are glycolipid-rich liquid domains of the plasma membrane, where certain types of protein tend to aggregate and intercalate. Lipid rafts are involved in the generation of amyloid-beta oligomers and the formation of amyloid-beta peptides. In this paper, we review the mechanism by which lipid rafts disturb the aberrant deg- radative autophagic-lysosomal pathway of amyloid-beta, which plays an important role in the pathological process of Alzheimer＇s disease. Moreover, we describe this mechanism from the view of the Two-system Theory of fasciology and thus, suggest that lipid rafts may be a new target of Alzheimer＇s disease treatment.

The contribution of attached Ulva prolifera on Pyropia aquaculture rafts to green tides in the Yellow Sea

Green tides caused by the unusual accumulation of high floating Ulva prolifera have occurred regularly in the Yellow Sea since 2007.The primary source of the Yellow Sea green tides is the attached algae on the Pyropia aquaculture rafts in the Subei Shoal.Ulva prolifera and Blidingia(Italic)sp.are the main species observed on Pyropia aquaculture rafts in the Subei Shoal.We found that U.prolifera has strong buoyancy and a rapid growth rate,which may explain why it is the dominant species of green tides that occur in the China's sea area of the Yellow Sea.The growth rate of floating U.prolifera was about 20%–31%d–1,which was much higher than Blidingia(Italic)sp.There were about 1.7×104 t of attached algae on the Pyropia aquaculture rafts in May 2012.We found that 39%of attached algae could float when the tide rose in the Subei Shoal,and U.prolifera accounted for 63%of the floating algae.Our analysis estimated that about 4000 t of attached U.prolifera floated into the surrounding waters of the Subei Shoal during the recycling period of aquaculture rafts.These results suggest that the initial floating biomass of large-scale green tides in the Yellow Sea is determined by the U.prolifera biomass attached to Pyropia aquaculture rafts,further impacting the scale of the green tide。

The Stability of Lipid Rafts-Like Micro-Domains Is Dependent on the Available Amount of Cholesterol

Lipid rafts are sterol and sphingolipid rich membrane domains that possibly may play roles in multiple cellular processes. These domains are still the matter of debate and it is still unknown by which mechanism if any and organisms promote their formation. This study centers on the ease of in vitro formation of lipid rafts-like structures as it relates to the relative availability of sphingolipids, phospholipids, cholesterol, and membrane proteins. Following a 12 h incubation period, isolation and extraction of the lipid rafts-like assemblies, the composition of the structures was evaluated using HPLC. Cholesterol and sphingomyelin were detected at 206 nm and phosphatidylcholine was detected at 254 nm. Identification of lactose permease, a typical membrane protein, was done using FTIR. The thermal stability of the produced structures was also determined. Results show that the addition of cholesterol significantly increased both the amount of insoluble lipid rafts-like structures and their stability, and that the availability of a minimum amount of sphingolipid was necessary to produce larger amounts of more stable structures. However, the addition of phospholipids hindered the formation of lipid rafts-like assemblies and those formed were generally less stable.

Emodin suppresses LPS-induced proinflammatory responses and nuclear factor-B activation by disruption of lipid rafts and TLR-4 recruitment in endothelial cells

Emodin [1,3,8-Trihydroxy-6-methylanthraquinone] has been reported to exhibit vascular anti-inflammatory properties.However,the relevant anti-inflammatory mechanisms are not well understood.The present study was design to explore the molecular target(s) of emodin

Energy Absorption by the Membrane Rafts in the Modulated Electro-Hyperthermia (mEHT)

Aim: Heating by nanoparticles, which are located in the tissue to be treated, is a well-recognized method in hyperthermic oncology. Our objective is to investigate selective, nanoscopic heating without concentrating extra artificial nanoparticles. We have in silico calculation to study the heating of the transmembrane protein clusters (rafts) on cell-membrane. The transmembrane protein domains have significantly higher dielectric constant than their lipid neighborhood in the membrane. This difference causes a local gradient in the Specific Absorption Rate (SAR), which could be a factor of heating of the membranes locally, as well as exciting the receptors for various signal transduction in the cells. We suppose that this process determines the observed cellular effects of modulated electro-hyperthermia (mEHT, trade-name: oncothermia). Materials and Methods: In silico models with highly specialized software (Computer Simulation Technology (CST), Darmstadt, Germany) were performed visualizing the selectivity for the membrane domains. Local raft models were created to simulate the electromagnetic (EM) effect of a 13.56 MHz excitation between two perfect electrical conductor plates, simulating the equipotential conditions of the sides of the membrane in the vicinity of the raft. The simulations were performed with near-field (EQS) solver of CST. The electric field, current density, and electric loss density were monitored by the simulations. The applied material properties and parameters refer to the recent literature. Results: In silico models show ten times higher energy-absorption of the transmembrane domains than that of its lipid-membrane surrounding, and intra- and extracellular neighborhood. Depending on the size, orientation, and location of the membrane rafts, the value of SAR varies, but we use only two simplified models to see the absorption properties. Taking into account the characteristics of the EM field effects we showed that the selective energy-absorption increased further by the cell-cell interactions. The model-calculation could confirm the opportunity of the local membrane heating. Conclusion: Our results indicate the heating in nanoscopic range with energy-absorption by the transmembrane proteins. The heated protein-clusters (membrane rafts) are used the same way as the artificial nanoparticles, while these absorbers are natural parts of the biological system.

Dynamics of Submersible Mussel Rafts in Waves and Current

To investigate the dynamics of submersible mussel rafts, the finite element program Aqua-FETM, developed by the University of New Hampshire（UNH）, was applied to rafts moored at the surface and submerged. The submerged configuration is used to reduce wave forcing and to avoid contact with floating ice during winters in northern waters. Each raft consists of three pontoons connected by a grid framework. Rafts are intended to support densely spaced mussel ropes hung from the framework. When submerged, the pontoons are flooded, and the raft is held vertically by floats attached by lines. The computer models were developed in Aqua-FE？ to simulate the effects of waves and current. They were validated by comparison with wave tank results by use of a 1/10 scale raft physical model. Comparisons showed good agreement for the important heave（vertical） and pitch（rotational） motions, though there was a tendency towards conservative results for wave and current drag. Full-scale simulations of surface and submerged single raft and two rafts connected in tandem were performed. Submerged raft wave response was found to be reduced relative to that at the surface for both the single and two-raft configurations. In particular, the vertical motion of mussel rope connection points was significantly reduced by submergence, resulting in reduced potential for mussel drop-off. For example, the maximum vertical velocities of mussel rope attachment points in the submerged two raft case were 7%-20% of the corresponding velocities when at the surface.

Deep Foundation Pit Excavations Adjacent to Disconnected Piled Rafts: A Review on Risk Control Practice

Foundation pit excavation engineering is an old subject full of decision making. Yet, it still deserves further research due to the associated high failure cost and the complexity of the geological conditions and/or the surrounding existing infrastructure around it. This article overviews the risk control practice of foundation pit excavation projects in close proximity to existing disconnected piled raft. More focus is given to geotechnical aspects. The review begins with achievements to ensure excavation performance requirements, and follows to discuss the complex soil structure interaction involved among the fundamental components: the retaining wall, mat, piles, cushion, and the soil. After bringing consensus points to practicing engineers and decision makers, it then suggests possible future research directions.

基于Raft的多主节点拜占庭容错共识机制

为了解决联盟链中实用拜占庭容错(PBFT)共识机制在区块链网络中节点数量增多的情况下,通信复杂度高、共识效率低下等问题,本文提出一种基于Raft的多主节点拜占庭容错共识机制IMRBFT。IMRBFT通过Maglev一致性哈希算法对区块链网络节点均匀分组,将这个共识流程分成组外共识和组内共识2部分。组内先选出领导者节点,通过信用机制将节点分为3个等级:可信节点、普通节点和不可信节点。与投票机制共同降低恶意节点成为领导者节点的概率,并与其他组的领导者节点组成委员会,委员会再经过组外信用值机制选出信用值最高的多个主节点进行组外PBFT共识。组内共识在Raft共识的基础上引入监管节点与中继节点,进一步提升安全性与共识效率,减少恶意节点的作恶行为。实验结果表明:IMRBFT的通信开销为线性增长,通信量为PBFT的41.6%,吞吐量为PBFT的4.2倍,共识延时降低76.4%。随着节点增多,优化更加明显,完全满足大型区块链网络的通信复杂度小、吞吐量高、共识延时短、安全性与共识效率高的要求。

低临界胶束浓度PEGMA-b-PCL的制备及其药物缓释性能

以ε-己内酯(ε-CL)为疏水链段、聚乙二醇甲醚甲基丙烯酸酯(PEGMA)为亲水链段、4-氰基-4-[(十二烷基硫烷基硫代羰基)硫烷基]戊醇(CDPA)为可逆加成-断裂链转移(RAFT)试剂、甲苯为溶剂,在N_(2)氛围、80℃、反应24 h的条件下,通过RAFT聚合法制备了两嵌段共聚物(PEGMA-b-PCL)。将其自组装为胶束,作为纳米药物载体用于负载姜黄素(Cur)。采用FTIR、^(1)HNMR、GPC、SEM、DLS对PEGMA-b-PCL进行了表征,测试了胶束载体的载药和释药性能。结果表明,两嵌段共聚物数均相对分子质量范围为1478~7318,其具有较低的临界胶束浓度(在pH=5.0~7.4,范围为0.920~1.600 mg/L)。胶束载体粒径范围为68.34~186.93 nm。当n(CDPA)∶n(ε-CL)=1∶200时,胶束载药率和包封率最高,可达12.05%±0.29%和75.26%±2.41%。在不同pH环境下,药物缓释性能可达15 d,其中pH=5.0时的累积释药率最高,可达38.20%。

基于改进Raft共识算法和PBFT共识算法的双层共识算法

针对目前应用于联盟链中的实用拜占庭(PBFT)共识算法可扩展性不足、通信开销增长过大、难以适用于大规模网络节点环境等问题,提出了一种基于改进Raft共识算法和PBFT共识算法的双层共识算法(DL_RBFT)。首先将区块链中的节点分成若干小组,组成下层共识网络,然后小组的组长再构成上层共识网络,形成一个双层共识网络结构;在下层共识网络的小组内部引入监督机制和声誉机制来改进Raft共识算法,在初始组长的选举流程引入了蚁群算法,使选举效率始终维持在较高水平;在上层共识网络中,使用PBFT共识算法进行共识。改进后的Raft共识算法具备了抗拜占庭节点攻击的能力,提升了算法的安全性。实验结果分析表明,相较于传统的PBFT共识算法,在100个节点的情况下,DL_RBFT将共识时延降低了两个数量级,吞吐量也提升了一个数量级,与其余改进算法相比也有着明显优势。因此DL_RBFT共识算法拥有良好的可扩展性,可以广泛应用于联盟链的各种场景中。

有机硅基RAFT试剂制备聚醚改性有机硅消泡剂

以八甲基环四硅氧烷和巯丙基甲基二甲氧基硅烷为原料,合成了巯基硅油;再以巯基硅油、CS_(2)和2-溴代异丁酸甲酯为原料,合成了有机硅基可逆加成-断裂链转移(RAFT)试剂(RAFT-SSO);RAFT-SSO与甲基封端的烯丙基聚氧乙烯醚(EO)、甲基封端的烯丙基聚氧丙烯醚(PO)采用RAFT聚合反应合成了聚醚改性有机硅消泡剂(RS-EOPO)。采用FTIR、^(1)HNMR,GPC对RS-EOPO进行了结构表征,对其消泡、抑泡、相容性进行了测试,并将RS-EOPO与进口消泡剂性能进行对比。RS-EOPO最佳合成工艺条件为RAFT-SSO相对分子质量为2000、m(EO)∶m(PO)=1∶4、m(RAFT-SSO)∶m〔醚(EO和PO)〕=1∶1.15、反应温度75℃、反应时间8 h、引发剂用量为EO(3.45 g)和PO总质量的2%。在上述条件下,RS-EOPO收率为91.8%。

基于RAFT的高速公路夜间交通事件检测

高速公路夜间交通事件检测对于提高救援效率、避免二次事故的发生至关重要。我国大部分高速公路都建成了完整的高速公路视频监控系统,但在夜间,高速公路交通事件检测仍采用人工检测,效率较低。通过分析高速公路夜间交通事件检测策略,文章基于RAFT深层网络,以夜间车辆光流形成的密集光流为检测对象,提出了夜间高速公路车辆检测深度学习网络,采用DeepSort算法对检测目标进行速度跟踪测量。利用实测数据对YOLOv5和研究提出的方法进行了比较,结果表明所提方法具有检测精度高、检测速度快等优点。

Lipid Rafts Identified on Synaptic Vesicles from Rat Brain

For a long time, lipid rafts have been thought to participate in regulating neurotransmitter release. However, the existence of lipid rafts on synaptic vesicles （SVs） and the mechanism by which exocytosisrelative proteins distribute on this structure have not been fully investigated. There is also much controversial data concerning rafts on SVs and synaptic vesicle proteins which makes the results difficult to interpret. This study systematically analyzed the existence and properties of lipid rafts on purified SVs by sucrose density gradient centrifugation, cholesterol depletion, and temperature variation. The data reveals that typical lipid rafts on SVs are both cholesterol dependent and temperature sensitive. Previous confusing results may have been caused by improper treatment or side effects of particular reagent. We also screened the lateral distribution of major exocytosis-related SV proteins and found that only the synaptobrevin （syb） and synaptotagmin （syt） produce detectable association with lipid rafts in 1% Triton X-100.

基于内聚力单元法的船舶与重叠冰碰撞数值模拟研究

The gradual increase in shipping and drilling activities in the Arctic regions has resulted in the increased importance of studying the structural safety of polar ships in various ice conditions.Rafted ice refers to a type of accumulated and overlapped sea ice;it is driven by external forces,such as wind and waves,and may exert high loads on ships and threaten their structural safety.Therefore,the properties of rafted ice and the construction of numerical models should be studied before exploring the interaction and collision between ships and rafted ice.Based on the nonlinear finite-element method,this paper introduces the cohesive element model for the simulation of rafted ice.The interaction between ships and rafted ice is studied,and the ice force of the hull is obtained.Numerical simulation results are compared with model test findings,and the effectiveness of the cohesive element method in the construction of the model of rafted ice materials is verified.On this basis,a multilayer rafted ice model is constructed,and its interaction with the ship is studied.The research unveils that rafted ice parts impede crack generation and slow down crack propagation to a certain extent.

谈谈RAFTS英语写作教学法

1985年4月美国全国英语教师联合会西北地区英语教学法讨论会上,蒙大拿大学英语系华裔教授贝弗莉·安·秦(Bevelley Ann Ching)等人推出RAFTS英语写作教学新法,

可控/精确自由基聚合技术的研究及应用进展

深入剖析了可控/精确自由基聚合技术(CPR)中的3种主要技术:可逆加成-破碎链转移聚合(RAFT)、原子转移自由基聚合(ATRP)和氮氧调控聚合(NMP)。概述了这些技术的基本概念,分析了各个技术方法的优缺点,列举了这些技术方法的应用领域。最后,对可控/精确聚合技术进行了总结和展望。

基于RAFT算法的数字医联体医疗信息跨平台共享方法

随着数字医联体的快速发展,实现医联体内部各医疗平台间信息的安全共享是急需解决的问题之一。因此,研究基于RAFT算法的数字医联体医疗信息跨平台共享方法。在分析数字医联体组建架构基础上,构建集信息采集和管理、信息的整合与分配、平台服务、应用服务于一体的信息跨平台共享体系。其中,信息整合与分配过程采用RAFT算法通过节点选举与日志复制两个功能,实现医疗信息的跨平台过程中数据请求方和数据提供方间的数据分配和共享,并采用PageRank算法优化RAFT算法节点关键性,提高其信息共享的完整性。实验中,该方法的最大可容忍恶意节点数量可达到16个;在45s的时间内,该方法可以采集近700条信息数据;在节点数量为17个时,本文方法的通信复杂度仅为262。实验表明:该方法对恶意节点容忍量更高,对海量医疗信息的提取更快,跨平台共享信息过程的通信复杂度较低。

基于RAFT的初中语文写作教学策略研究

随着课程改革深入发展,中小学语文写作教学的重视程度逐渐提高,在教学实践中不断探索写作教学的新方法。RAFT写作教学方法主要通过设定写作任务的角色、读者、方式和主题等要素来帮助学生明确写作的目的和对象,提高写作的针对性和实际效果。在初中写作教学中可以从准备策略、实施策略、评价策略三方面入手进行RAFT写作教学四要素的渗透,从而转变写作教学观念,明确写作教学的流程要素,提高学生写作能力,促进学生语文学习思维的发展。

主客体相互作用实现含氟单体水相聚合诱导自组装

论文致力于高浓度高重现性的精准制备含氟组装体,同时将微波辅助用于聚合诱导自组装(PISA),建立微波辅助含氟单体水相PISA新方法。引入随机甲基-β-环糊精(MCD)与含氟疏水单体形成水溶性主客体复合物,在微波辅助下成功制备不同粒径的组装体,通过接触角的测试,证明了含氟微球具有良好的成膜性能和疏水性能,可以用作含氟水性涂料。

Toy model that explains the regulation of cholesterol on lipid rafts

Cholesterol,as a common lipid on mammalian cell membranes,plays an important role in the formation of lipid rafts.Recent experiments suggest that the strength of cholesterol's regulation on lipid rafts can be affected by the length of the unsaturated phospholipid acyl chain on the membrane.In order to understand this observation,a simplified toy model containing three different molecules is proposed in this paper,where the tail length of phospholipids is considered.This model shows the regulation of membrane cholesterol on the phase separation of the lipid mixture and the formation of nano-domains,and also suggests that the configuration entropy of phospholipid tails is an essential factor.