3D-printed integrative probeheads for magnetic resonance

射频探头前端作为核磁共振设备的核心部件之一，极大程度的决定着系统实验性能的优劣。探头前端通常由射频线圈、射频电路及样品检测管道等部分组成。现有的射频线圈制作技术主要是通过手工或机械手段按照所需的线圈形状进行绕制。但是，当线圈结构较为复杂、不规则，或体积尺寸较小时，常规绕制方法便难以满足结构设计和制造的精度需求，因此造成线圈性能的劣化，增大检测区域的射频场不均匀性，对核磁共振检测产生负面影响。本研究中，利用3D打印熔融沉积制造或光敏树脂选择性固化技术精确加工出一体化磁共振探头前端，使用常温液态金属填充线圈模型管路形成射频线圈，搭建出稳定的一体化磁共振射频探头。利用高精度3D打印和液态金属灌注技术制备出包含有射频线圈和定制化样品管道结构在内的一体化磁共振射频探头前端，克服了传统磁共振三维微型线圈成型困难、与样品腔匹配程度差等问题，提高了探头的信噪比，为定制化的磁共振检测提供了新思路。 该工作由厦门大学电子科学与技术学院陈忠教授、游学秋副研究员和孙惠军高级工程师共同指导完成，博士研究生谢君尧为论文第一作者。厦门大学电子科学与技术学院黄玉清高级工程师、王忻昌副教授、倪祖荣助理教授、硕士研究生张德超，化学化工学院杨朝勇教授、博士研究生李星锐，萨本栋微米纳米科学技术研究院陈宏教授为合作作者。【Abstract】Magnetic resonance (MR) technology has been widely employed in scientific research, clinical diagnosis and geological survey. However, the fabrication of MR radio frequency probeheads still face difficulties in integration, customization and miniaturization. Here, we utilized 3D printing and liquid metal filling techniques to fabricate integrative radio frequency probeheads for MR experiments. The 3D-printed probehead with micrometer precision generally consists of liquid metal coils, customized sample chambers and radio frequency circuit interfaces. We screened different 3D printing materials and optimized the liquid metals by incorporating metal microparticles. The 3D-printed probeheads are capable of performing both routine and nonconventional MR experiments, including in situ electrochemical analysis, in situ reaction monitoring with continues-flow paramagnetic particles and ions separation, and small-sample MR imaging. Due to the flexibility and accuracy of 3D printing techniques, we can accurately obtain complicated coil geometries at the micrometer scale, shortening the fabrication timescale and extending the application scenarios.The work is supported by the National Natural Science Foundation of China (Grants U1632274, 11761141010, U1805261, 11475142, 22073078, and 61801411), and China Postdoctoral Science Foundation (2017M622075).研究工作得到国家自然科学基金、中国博士后科学基金等项目支持

Genomic Insights into the Formation of Human Populations in East Asia

厦门大学人类学研究所、厦门大学生命科学学院细胞应激生物学国家重点实验室王传超教授课题组与哈佛医学院David Reich教授团队合作，联合全球43个单位的85位共同作者组成的国际合作团队通过古DNA精细解析东亚人群形成历史。研究人员利用古DNA数据检验了东亚地区农业和语言共扩散理论，综合考古学、语言学等证据，该研究系统性地重构了东亚人群的形成、迁徙和混合历史。这是目前国内开展的东亚地区最大规模的考古基因组学研究，此次所报道的东亚地区古人基因组样本量是以往国内研究机构所发表的样本量总和的两倍，改变了东亚地区尤其是中国境内考古基因组学研究长期滞后的局面。 该研究是由王传超教授团队与哈佛医学院（David Reich教授）、德国马普人类历史科学研究所（Johannes Krause教授）、复旦大学现代人类学教育部重点实验室（李辉教授和金力院士）、维也纳大学进化人类学系（Ron Pinhasi副教授）、南洋理工大学人文学院（Hui-Yuan Yeh助理教授）、俄罗斯远东联邦大学科学博物馆（Alexander N Popov研究员）、西安交通大学（张虎勤教授）、蒙古国国家博物馆研究中心、乌兰巴托国立大学考古系、华盛顿大学人类学系、台湾成功大学考古所、加州大学人类学系等全球43个单位的85位共同作者组成的国际合作团队联合完成的。厦门大学人类学研究所、厦门大学生命科学学院细胞应激生物学国家重点实验室为论文第一完成单位。厦门大学人类学研究所韦兰海副教授、胡荣助理教授、郭健新博士后、何光林博士后和杨晓敏硕士参与了研究工作。The deep population history of East Asia remains poorly understood due to a lack of ancient DNA data and sparse sampling of present-day people1,2. We report genome-wide data from 166 East Asians dating to 6000 BCE-1000 CE and 46 present-day groups. Hunter-gatherers from Japan, the Amur River Basin, and people of Neolithic and Iron Age Taiwan and the Tibetan plateau are linked by a deeply-splitting lineage likely reflecting a Late Pleistocene coastal migration. We follow Holocene expansions from four regions. First, hunter-gatherers of Mongolia and the Amur River Basin have ancestry shared by Mongolic and Tungusic language speakers but do not carry West Liao River farmer ancestry contradicting theories that their expansion spread these proto-languages. Second, Yellow River Basin farmers at ～3000 BCE likely spread Sino-Tibetan languages as their ancestry dispersed both to Tibet where it forms up ～84% to some groups and to the Central Plain where it contributed ～59-84% to Han Chinese. Third, people from Taiwan ～1300 BCE to 800 CE derived ～75% ancestry from a lineage also common in modern Austronesian, Tai-Kadai and Austroasiatic speakers likely deriving from Yangtze River Valley farmers; ancient Taiwan people also derived ～25% ancestry from a northern lineage related to but different from Yellow River farmers implying an additional north-to-south expansion. Fourth, Yamnaya Steppe pastoralist ancestry arrived in western Mongolia after ～3000 BCE but was displaced by previously established lineages even while it persisted in western China as expected if it spread the ancestor of Tocharian Indo-European languages. Two later gene flows affected western Mongolia: after ～2000 BCE migrants with Yamnaya and European farmer ancestry, and episodic impacts of later groups with ancestry from Turan.We thank David Anthony, Ofer Bar-Yosef, Katherine Brunson, Rowan Flad, Pavel Flegontov,Qiaomei Fu, Wolfgang Haak, Iosif Lazaridis, Mark Lipson, Iain Mathieson, Richard Meadow,Inigo Olalde, Nick Patterson, Pontus Skoglund, Dan Xu, and the four reviewers for valuable comments. We thank Naruya Saitou and the Asian DNA Repository Consortium for sharing genotype data from present-day Japanese groups. We thank Toyohiro Nishimoto and Takashi Fujisawa from the Rebun Town Board of Education for sharing the Funadomari Jomon samples, and Hideyo Tanaka and Watru Nagahara from the Archeological Center of Chiba City who are excavators of the Rokutsu Jomon site. The excavations at Boisman-2 site (Boisman culture), the Pospelovo-1 site (Yankovsky culture), and the Roshino-4 site (Heishui Mohe culture) were funded by the Far Eastern Federal University and the Institute of History,Archaeology and Ethnology Far Eastern Branch of the Russian Academy of Sciences; research on Pospelovo-1 is funded by RFBR project number 18-09-40101. C.C.W was funded by the Max Planck Society, the National Natural Science Foundation of China (NSFC 31801040), the Nanqiang Outstanding Young Talents Program of Xiamen University (X2123302), the Major project of National Social Science Foundation of China (20&ZD248), a European Research Council (ERC) grant to Dan Xu (ERC-2019-ADG-883700-TRAM) and Fundamental Research Funds for the Central Universities (ZK1144). O.B. and Y.B. were funded by Russian Scientific Foundation grant 17-14-01345. H.M. was supported by the grant JSPS 16H02527. M.R. and C.C.W received funding from the ERC under the European Union’s Horizon 2020 research and innovation program (grant No 646612) to M.R. The research of C.S. is supported 30 by the Calleva Foundation and the Human Origins Research Fund. H.L was funded NSFC (91731303, 31671297), B&R International Joint Laboratory of Eurasian Anthropology (18490750300). J.K. was funded by DFG grant KR 4015/1-1, the Baden Württemberg Foundation, and the Max Planck Institute. Accelerator Mass Spectrometry radiocarbon dating work was supported by the National Science Foundation (NSF) (BCS-1460369) to D.J.K. and B.J.C. D.R. was funded by NSF grant BCS-1032255, NIH (NIGMS) grant GM100233, the Paul M. Allen Frontiers Group, John Templeton Foundation grant 61220, a gift from Jean-Francois Clin, and the Howard Hughes Medical Institute. 该研究得到了国家自然科学基金“中国东南各族群的遗传混合”、国家社科基金重大项目“多学科视角下的南岛语族的起源和形成研究”、厦门大学南强青年拔尖人才支持计划A类、中央高校基本科研业务费等资助

Theoretical Analysis Based on Particle Electro-Mechanics for Au Pearl Chain Formation

This paper analyzes the fundamental mechanisms in driving Au Pearl Chain Formation (PCF) based on dielectrophoresis (DEP) force. From experimental results, the PCF process strongly depends on the voltage and the frequency applied on electrodes, but weakly on the sizes of particles, which appears to be contrary to theoretical expectations. To explain the above phenomenon, we estimated the DEP force and the Brownian motion imposed on the Au nanoparticles, and then investigated the AC electro-osmosis force and the electro-thermal force which may possibly affect the PCF rate. Numerical modeling to compare the forces is presented. By matching experimental and numerical results, we validate the scaling laws of the DEP force and electro-mechanics in the PCF of Au nanoparticles

Identify the model of micro robotic gripper using the sequence of microscopic images

This paper reports on the construction of the computer micro vision system to identify the model micro robotic gripper. Several focus measure algorithm may be used to process the microscopic images. While sum-modified-Laplacian (SML) based focus measure is used in sequence of microscopic images for measuring the displacement of the micro robotic gripper in this paper. We show the bending curve of the microactuator with the input current 3mA, 4mA, 5mA

Identify the model of micro robotic gripper using the sequence of microscopic images

This paper reports on the construction of the computer micro vision system to identify the model micro robotic gripper. Several focus measure algorithm may be used to process the microscopic images. While sum-modified-Laplacian (SML) based focus measure is used in sequence of microscopic images for measuring the displacement of the micro robotic gripper in this paper. We show the bending curve of the microactuator with the input current 3mA, 4mA, 5mA

Finite element modeling of a thermally actuated polymer micro robotic gripper

This paper describes the structural and thermal model of a thermally actuated polymer micro robotic gripper. The basic structure for the gripper is a trimorph thermal actuator with a platinum metal heater encapsulated by parylene C polymer layers. Due to the large difference of thermal expansion coefficients of the different layers, the actuator can be actuated with much large deflection. In this paper, we present a finite-element modeling of thermal and the thermo-mechanical behavior simulation of this kind gripper

Thermo metry of photo sensitive and optically induced electrokinetics chips

Optically induced electrokinetics (OEK)-based technologies, which integrate the high-resolution dynamic addressability of optical tweezers and the high-throughput capability of electrokinetic forces, have been widely used to manipulate, assemble, and separate biological and non-biological entities in parallel on scales ranging from micrometers to nanometers. However, simultaneously introducing optical and electrical energy into an OEK chip may induce a problematic temperature increase, which poses the potential risk of exceeding physiological conditions and thus inducing variations in cell behavior or activity or even irreversible cell damage during bio-manipulation. Here, we systematically measure the temperature distribution and changes in an OEK chip arising from the projected images and applied alternating current (AC) voltage using an infrared camera. We have found that the average temperature of a projected area is influenced by the light color, total illumination area, ratio of lighted regions to the total controlled areas, and amplitude of the AC voltage. As an example, optically induced thermocapillary flow is triggered by the light image-induced temperature gradient on a photosensitive substrate to realize fluidic hydrogel patterning. Our studies show that the projected light pattern needs to be properly designed to satisfy specific application requirements, especially for applications related to cell manipulation and assembly.</p

An AFM based nanomanipulation system with 3D nano forces feedback

In the AFM based nanomanipulation, the main problem is the lack of real-time sensory feedback for an operator, which makes the manipulation almost in the dark and inefficient. For solving this problem, the AFM probe micro cantilever-tip is used not only as an end effector but also as a 3D nano forces sensor for sensing the interactive nano forces between the AFM probe tip and the object or substrate in nanomanipulation. In addition, for a sample-scanning AFM even with a strain gauge position feedback sensor for x-y close-loop displacement control of sample stage, scanning size error will still be generated, which is destructive to lateral positioning accuracy of AFM probe. For improving probe lateral positioning accuracy, an error compensating method is adopted according to system error quantitative analysis based on the authors' previous work. With 3D nano forces sensing through a haptic/force device and probe positioning accuracy improvement, the efficiency and accuracy of nano manipulation can be significantly improved. Experiments are presented to verify the effectiveness of the nanomanipulation system

Vibration-Mode Based Real-Time Nanoimaging and Nanomanipulation

A novel method based on vibration-mode of the atomic force microscope (AFM) for nanoimaging and nanomanipulation is introduced in this paper. With this approach, the amplitude of OMSPV (opto-electronic measurement signal of probe vibration) can be used as a feedback signal to detect and control the operation state under vibration-mode. By controlling the amplitude of AFM probe, the tip-sample interaction force can be sufficiently adjusted. Therefore, vibration-mode of AFM system can be used to manipulate nano-entities just as in using the standard contact-mode manipulation strategy. Using the novel method, nanoimaging and nanomanipulation could both be performed in vibration-mode, and the damages of the sample and probe tip can be reduced significantly. Furthermore, by detecting the amplitude of OMSPV change during operation, the precise position information between the probe tip and nano-entities (e.g., CNTs) can be determined automatically as well. Experiments show that the amplitude of OMSPV will be in USPV (unstable state of probe vibration) when the tip is at the edge of CNTs due to the real-time adjustment of parameters of the AFM control system. Such USPV can be used to determine whether the manipulation succeeds in real-time. The correlative analysis and signal processing method is also presented in the paper