Application of Fluorescent Probe Technique in Study of Polymer Self-Assembly

采用自组装技术制备新型功能性材料已成为聚合物材料的一个热门研究领域。大部分两亲性聚合物,如嵌段聚合物、接枝聚合物、星型聚合物、树枝状聚合物和部分无规聚合物及聚电解质,在特定条件下可发生自组装。在聚合物自组装的研究中,荧光技术已经得到了广泛的应用,尤其是荧光探针技术。根据荧光探针分子荧光光谱特征峰荧光波长、强度、偏振以及寿命等参数的变化,可以简便而又准确地研究聚合物的临界胶束浓度、温度和PH敏感性、结构与自组装形态的关系、微环境变化等信息。本文综述了荧光探针技术在两亲性聚合物自组装行为研究中的应用,重点介绍了荧光探针技术研究聚合物亲水亲油平衡值(Hlb值)、浓度、温度、PH、溶剂组成及离子强度等因素对聚合物自组装形貌和微观特性参数的影响。此外,结合我们的研究工作对本征荧光光谱方法在聚合物研究中的应用做了阐述和展望,以期为两亲性聚合物的设计合成、自组装行为控制及应用提供参考。Preparation of new functional materials by self-assembly technique has become a hot research field of polymeric materials science.Most of the amphiphilic polymers,such as block copolymers,graft copolymers,star copolymers,dendrimers,part of the random copolymer and polyelectrolyte,etc.can self-assemble under certain conditions.In the study of polymer self-assembly,fluorescent technique has been widely used,especially fluorescent probe technique.According to the changes of the characteristic fluorescence parameters of the probe molecules,such as wavelength,intensity,polarization,lifetime,etc.the critical micelle concentration,temperature and pH dependence,the relationship of structure and self-assemble morphology of the polymer could be easily and accurately studied.This paper is focused on the application of the fluorescent probe technique in investigation of self-assembly behavior of amphiphilic polymers.The effects of hydrophilic lipophilic balance(HLB),concentration,temperature,pH,solvent composition,ionic strength,etc.on self-assemble morphology and microscopic characteristics parameters of amphiphilic polymers are particularly reviewed.Furthermore,based on our own research work,the applications of intrinsic fluorescence spectroscopy method in polymer investigation are elaborated.It will characterize the conformation transitions of macromolecules during the self-assembly process more truly.This paper aims at providing reference for design,polymerization,self-assembly controlling and applications of amphiphilic polymers.国家自然科学基金项目(No.51103123); 福建省自然科学基金项目(No.2012J01234)资

南海北部天然气水合物的形成分解与微生物的偶联关系

微生物在天然气水合物的形成和分解中扮演了重要的角色.南海北部是我国天然气水合物未来开发的战略选区之一,目前已多次在该海域采集到天然气水合物样品,证实了南海北部蕴藏着丰富的天然气水合物资源.通过分析天然气水合物形成与分解同微生物的偶联关系,综述了与天然气水合物形成分解有关的微生物类型及其标志化合物,结合我国南海北部天然气水合物赋存或潜在赋存区的微生物相关研究工作进展,提出未来使用微生物地球化学方法勘探天然气水合物的技术指标和相关的研究方向.国家自然科学基金(41773078,41276046);;厦门大学校长基金(0050-ZK1104

类泛素蛋白及其中文命名

泛素家族包括泛素及类泛素蛋白,约20种成员蛋白.近年来,泛素家族领域取得了迅猛发展,并已与生物学及医学研究的各个领域相互交叉.泛素家族介导的蛋白质降解和细胞自噬机制的发现分别于2004和2016年获得诺贝尔奖.但是,类泛素蛋白并没有统一规范的中文译名. 2018年4月9日在苏州召开的《泛素家族介导的蛋白质降解和细胞自噬》专著的编委会上,部分作者讨论了类泛素蛋白的中文命名问题,并在随后的\"泛素家族、自噬与疾病\"(Ubiquitinfamily,autophagy anddiseases)苏州会议上提出了类泛素蛋白中文翻译草案,此草案在参加该会议的国内学者及海外华人学者间取得了高度共识.冷泉港亚洲\"泛素家族、自噬与疾病\"苏州会议是由美国冷泉港实验室主办、两年一度、面向全球的英文会议.该会议在海内外华人学者中具有广泛影响,因此,参会华人学者的意见具有一定的代表性.本文介绍了10个类别的类泛素蛋白的中文命名,系统总结了它们的结构特点,并比较了参与各种类泛素化修饰的酶和它们的生物学功能.文章由45名从事该领域研究的专家合作撰写,其中包括中国工程院院士1名,相关学者4名,长江学者3名,国家杰出青年科学基金获得者18名和美国知名高校华人教授4名.他们绝大多数是参加编写即将由科学出版社出版的专著《泛素家族介导的蛋白质降解和细胞自噬》的专家

基于格子Boltzmann方法的固-液搅拌槽直接数值模拟研究

搅拌槽作为常见的单元操作设备在工业上有广泛的运用，其中固-液体系搅拌槽常用于化工、冶金、矿业、医药、环保等领域。固-液搅拌槽中颗粒动力学的研究对搅拌槽的设计、放大以及操作优化至关重要。该领域的研究主要针对固液混合特性和颗粒动力学两个方面的关键问题。其中，固液混合特性主要关注颗粒在搅拌槽中的运动规律，包括重质颗粒的悬浮、轻质颗粒的下拉，以及颗粒在搅拌槽中的聚集现象等。这一问题的研究与搅拌槽在工业上的应用密切相关。颗粒动力学则着眼于颗粒在搅拌槽中的受力情况，搅拌槽中颗粒动力学描述准确与否将直接影响搅拌槽数值模拟结果的正确性。本文将针对上述两个问题，重点研究颗粒聚集现象和搅拌槽中的颗粒动力学。目前二者面临的共同难点在于，实验和传统模拟方法在处理两个问题时均存在较大的局限。对于颗粒聚集现象，传统的E-E和E-L模拟方法无法处理体系中的有限体积颗粒，实验则受限于实验材料无法对各个变量的影响进行系统的考察。至于颗粒动力学的研究，实验和传统的模拟方法均无法测量或计算得到搅拌槽中颗粒的真实受力，也无从对其进行分析。因此，由于缺少合适的研究方法，对这两个问题的认识还十分有限。近年来，基于格子Boltzmann方法的全求解的直接数值模拟迅速发展，为搅拌槽的相关研究提供了新的路径，从而可以实现对搅拌槽中颗粒聚集和动力学的更深入的研究。有鉴于此，本文利用格子Boltzmann方法对固-液搅拌槽进行模拟，并在此基础上对搅拌槽中的颗粒聚集现象和颗粒动力学进行了系统的研究。具体工作及结论如下：（1）作为格子Boltzmann方法的运用，第一部分工作中利用该方法耦合Shan-Chen模型，研究了通道形状及壁面性质对微通道中液相流动的影响。首先，研究了缩口疏水微通道中二者对通量的影响。结果表明，在缩口微通道中，疏水壁面仍会提高通道的流体通过能力，且流量与滑移长度成线性正相关。其次，倾斜疏水壁面的存在还会改变通道中的流型，使疏水微通道中的液相流量呈现出独特的变化规律。此外，还对组合壁面性质的微通道进行了模拟。模拟结果表明，疏水直通道中的流量与疏水壁面的长度线性相关，壁面性质的交错形式对流量的影响较小。在缩口通道中也存在类似的规律，更多的疏水段也更有利于流体的通过。（2）在上述工作的基础上，进一步结合浸没边界法和硬球模型建立了搅拌槽的直接数值模拟程序框架。其中，浸没边界法用于模拟桨叶和颗粒的固壁边界，硬球模型则用于处理颗粒与不同固壁边界发生的碰撞事件。进而对低Reynolds数搅拌槽中的颗粒聚集现象进行了系统模拟，先后考察了颗粒初始位置、颗粒密度、颗粒直径、以及搅拌槽Reynolds数对搅拌槽中颗粒运动的影响。模拟结果表明，搅拌槽Reynolds数小于100的体系中颗粒有其特有的平衡区域，颗粒聚集现象的实质是颗粒群中具有相同性质的颗粒进入同样的稳定运动轨道。不同初始位置的颗粒均存在往平衡区域运动的趋势，但距离平衡区域较远的颗粒需要较长的诱导时间。颗粒平衡区域的位置与颗粒密度和搅拌槽Reynolds数相关。颗粒密度较小或搅拌槽Reynolds数较高的体系中，平衡区域将更靠近液相流动的涡的位置。反之亦然。当桨叶转速过快时，搅拌槽中的流动湍动较大，流体和颗粒运动呈现出一定的随机性，此时不会发生颗粒的聚集。另外，在本文研究的粒径范围内，粒径对平衡区域影响较小。（3）在前两项工作的基础上，将研究对象拓展含更多颗粒的体系，用以研究颗粒群在搅拌槽中的颗粒动力学行为。采用对模拟结果进行系综平均的方法，基于搅拌槽中流动的拟稳态假设对Eulerian-Eulerian方程进行简化，提出搅拌槽中的相间作用力分析方法。通过对比数值模拟方法得到的相间作用力和颗粒相的随体导数，验证假设的合理性和方法的可行性。在此基础上对搅拌槽中的压力梯度力以及曳力对颗粒运动的影响进行了探究。结果表明，搅拌槽中的压力分布与颗粒相性质无关，与搅拌槽Reynolds数相关，但压力梯度力对颗粒运动的影响程度却主要取决于颗粒性质，与搅拌槽Reynolds数无关。搅拌槽中颗粒受到的曳力与固液密度比、局部颗粒Reynolds数相关，随着局部颗粒Reynolds数的增加，颗粒受到的曳力呈现出先增加后平稳的变化趋势。根据模拟结果，本文提出了考虑固液密度比和局部湍动能影响的曳力模型。;Solid-liquid stirred tanks are widely used in chemical, metallurgical, pharmaceutical industry and environmental engineering. The study of particle dynamics in solid-liquid stirred tank is critical to its design, scale-up and operation optimization. The study of solid-liquid stirred tanks mainly includes two interrelated scientific problems: solid-liquid mixing characteristics and particle dynamics. To be more specific, the solid-liquid mixing characteristics mainly focus on the movement of particles in a stirred tank, including the suspension of heavy particles, the drawn-down of light particles and the aggregation of particles in a stirred tank. This kind of study is very significant to the use of stirred tanks in engineering; And the study of particle dynamics focuses on the interaction forces exerted on particles in a stirred tank, which provides important information for stirred tank simulation.For the research problems mentioned in the above, this thesis mainly focuses on the phenomenon of particles aggregation and particle dynamics in the stirred tank, because we notice that these two problems have the common ground that the experiment and traditional simulation methods have encountered great difficulties in studying these two problems. The lack of proper research methods leads to few studies about these subjects reported, and many technical problems still need to be solved. Recently, as the development of the lattice Boltzmann method (LBM), a novel high resolution direct numerical simulation was proposed to simulate the solid-liquid stirred tank, which is very suitable for studying these two scientific problems in stirred tanks. Therefore, the main idea of this work is to simulate the solid-liquid stirred tank based on the lattice Boltzmann method, aiming at a systematical study of the particle aggregation phenomenon and particle dynamics in a stirred tank. The specific scope and results are as follows:(1) In Chapter 2, as an application of LBM, the influence of microchannel shape and wall properties on the flow flux is studied by LBM coupled with the Shan-Chen model for modeling different hydrophobic channel walls. Firstly, the effect of channel shape and wall properties on the flux in the variable cross-section microchannel is studied. The results show that the hydrophobic surface in the microchannel can increase the fluid flux through the channel, and the flow flux is linearly and positively correlated with the slip length. Moreover, the presence of the inclined hydrophobic wall changes the flow pattern in the channel, so that the flux variation law in the hydrophobic microchannel exhibits a different tendency from a macrochannel. Subsequently, the microchannels with wetting and non-wetting walls are simulated. The results show that the flow flux in a straight hydrophobic channel is linearly related to the length of hydrophobic wall, and has little relation to the staggered arrangement of surface properties. A similar result can be found in the variable cross-section channel, and more non-wetting surface also can improve the flux in such channels.(2) Based on the LBM simulation of single-phase flow mentioned above, a direct numerical simulation program for a stirred tank is established by combining the immersed boundary method and the hard sphere model. The immersed boundary method is used to simulate the solid wall of impeller and particles. The hard sphere model is used here to deal with the collision events of a particle with other particles and solid wall. On this basis, the particle aggregation phenomenon in the low Reynolds number agitation tank is simulated. The effects of initial position of the particles, particle density, particle diameter and stirred tank Reynolds number on particle motion are investigated. The simulation results show that the particles in low Reynolds number agitation tank have their unique equilibrium regions. And the essence of the particle aggregation is that each individual particle in particle swarm approaches gradually the same stable orbit of motion. Particles at different initial positions all have the tendency to move toward to the same equilibrium region, but the particles far from this region require a longer induction time. The location of equilibrium region is related to the particle density and stirred tank Reynolds number. The light particle and high Reynolds number induce an equilibrium region, which is close to the center of vortex of liquid circulation flow, and vice versa. Besides, when the rotation speed of impeller is too fast, the flow in the stirred tank will fluctuate violently, the movement of fluid and particles exhibits more and stronger random fluctuations, and the aggregation of particles does not occur at this condition. In addition, within the particle size range studied in this paper, the particle size has little influence on the equilibrium region.(3) Base on the direct numerical simulation program for stirred tanks developed above, we extend it to simulate a system with more particles for studying the particle dynamics in a stirred tank. Based on the assumption of quasi-steady flow in a stirred tank, the simplified Eulerian-Eulerian equation and the ensemble averaged simulation results are used to analyze the interaction forces exerted on particles in a stirred tank. By comparing the interaction force calculated by the immersed boundary method and the material derivative of solid phase, the rationality of the hypothesis and feasibility of this analysis method are verified. Then the pressure gradient force and drag force in a stirred tank can be obtained through simulation. And the results show that the pressure distribution in a stirred tank is independent from the solid phase properties, but related to the stirred tank Reynolds number. It is interesting to find that the degree of influence of pressure gradient force on the particle motion depends mainly on the particle properties. The drag force in a stirred tank is related to the solid-liquid density ratio and the local particle Reynolds number. With the increase of local particle Reynolds number, the drag force increases firstly and then tends to an asymptotic value. Based on the drag force simulation results, an empirical correlation for stirred tanks is proposed by considering the influence of solid-liquid density ratio, local particle Reynolds number and local liquid energy dissipation.&nbsp;</p

复杂形状的疏水微通道的LBM模拟

随着微机电系统的发展和广泛应用,人们发现由于系统尺度的缩小,使得体系的面体比增大,在宏观系统中可以忽略的表面作用力在微尺度系统中变得不可忽视。宏观流体力学中经典的无滑移边界在微尺度系统中被证实不再适用。因此,液体在微米乃至纳米尺度构件中的独特的流动特性引起了人们的重视。目前,微流动的应用技术发

Underwater acoustic communication system with trellis coded modulation (TCM) technique and DSP implementation

阐述了网格编码调制(TCM)的原理及其在水声通信中的应用。采用TI公司的高性能DSP芯片TMS320C542实现了一个可以进行字符传输的水下无线通信系统。试验结果表明,网格编码调制技术能够使水下无线通信系统的性能得到明显改善。This paper discusses in detail the principle for Trellis Coded Modulat ion (TCM) and its application in underwater acoustic communication. The authors have implemented an underwater wireless communication system with the ability of character transmission by adopting high performance DSP chip TMS320C542 produced by TI Company. The testing result indicates that the Trellis Coded Modulation technique can improve evidently the performance with underwater wireless commun ication system.国家自然科学基金项目(60272028);; 福建省自然科学基金项目(D0110004

基于高通量测序分析骨肉瘤发生和转移的分子特征

目的本研究通过第二代高通量测序（NGS）检测配对骨肉瘤转移灶和原发灶标本，分析骨肉瘤原发灶与转移灶的基因图谱差异，以期发现促进骨肉瘤发生和转移的相关分子及可能机制。方法12例转移患者的原发灶与转移病灶肿瘤组织样本，使用第二代高通量测序（NGS）进行检测，其中9对panel检测（678个基因）以及3对全外显子检测（WES），分析比较骨肉瘤原发灶与转移灶的基因图谱差异：基因拷贝数变异通过EXCAVATOR检测；DNA层面的融合突变通过Lumpy检测；RNA层面的融合突变通过Defuse + STAR-Fusion，并通过Circos图显示突变的分布；Metascape 用于分析差异基因的 GO 和 KEGG 信号通路富集；使用Pyclone+Citup / LICHEE进行克隆进化分析。结果骨肉瘤基因总体突变模式主要以基因扩增为主，主要包括FLCN（37.5%），GID4（37.5%），TP53（33.3%），ATRX（25%），CALR（25%），CCND3（25%），CCNE1（25%），NOCR1（25%），TFEB（25%），VEGFA（25%）等基因。GO聚类结果提示细胞周期通路突变频率最高。KT1、PLCG2、EGFR这3个基因在转移灶显著富集的信号通路中多次出现，可能与骨肉瘤的转移密切相关。转移灶肿瘤负荷突变（TMB）频率显著高于原发灶（P=0.013）。3例进行WES检测的转移患者均呈现线性克隆进化，提示骨肉瘤转移基因的突变可能呈次序性累积。同时我们确定了可能在骨肉瘤进展中发挥作用的新候选基因，包括PLCG2、MYO15A与PEX6。结论骨肉瘤发生与转移的基因突变模式主要以基因扩增为主，骨肉瘤患者肿瘤负荷突变频率在转移灶中显著高于原发灶，转移患者存在相互关联的线性基因克隆进化。本研究发现了可能在骨肉瘤进展中发挥作用的3个新基因PLCG2、MYO15A和PEX6

底座入土深度和面积对典型草原土壤呼吸测定结果的影响

生态学家对土壤呼吸开展了大量研究,但很少评估"底座"对土壤呼吸测量结果的影响,特别是底座入土深度和面积对土壤呼吸测定结果的影响。为此,该研究在内蒙古典型草原设置了2个底座面积(15 cm×15 cm和30 cm×30 cm)和2个底座入土深度(2cm和5cm)处理,采用气室法在植物生长季对土壤呼吸进行了测定,分析评估了底座面积和入土深度对土壤呼吸测定结果的影响。结果显示:与底座入土较浅和面积较小的处理相比,底座入土较深和面积较大的处理,土壤呼吸测定值分别降低了8.0%–9.7%和9.1%–10.8%;这两个处理的底座内土壤温度显著升高,土壤含水量显著下降,地上净初级生产力显著降低。结构方程模型分析表明,底座入土较深、面积较大的处理,主要通过降低地上净初级生产力和土壤含水量,增加土壤温度,使土壤呼吸下降,各因子共同解释了土壤呼吸变异的89%。研究发现,在使用气室法测定土壤呼吸时,底座入土深度和面积对土壤呼吸测定结果具有显著影响,评估底座处理效应对准确测定土壤呼吸强度具有重要的意义。理论上,适当降低底座入土深度和底座面积大小,将有助于准确测定土壤呼吸。但在实践中,由于土壤异质性的影响,减少底座面积可能会增加新的测量误差,只能考虑适当降低底座入土深度