Preface to Special Topic: Papers from the 13th International Conference on Surface and Colloid Science (ICSCS) and the 83rd ACS Colloid and Surface Science Symposium, Columbia University, New York, 2009

This Special Topic section is a compilation of several original contributions covering both fundamental and practical aspects of electrokinetic microfluidic phenomena that were presented during the Electrokinetics and Microfluidics sessions held at the conference.Electrokinetics is currently the mechanism of choice for the manipulation of fluids as well as colloidal and biological particles at microscale and nanoscale dimensions.¹ The popularity of electrokinetics is perhaps not so surprising as electrodes are easy to fabricate and embed into microfluidic chips, thus allowing the entire fluid and particle actuation mechanism to be completely integrated into the device. In addition, driving microfluidics with electric fields is relatively straightforward and allows for precise actuation. Nevertheless, considerable challenges remain in understanding the complex mechanisms associated with the hydrodynamics of conducting and dielectric fluids and particles under the influence of electric fields. Concomitantly, there has been an exponential increase in research and development in this field along both fundamental and applied themes in the past five years.This sustained growth in the microfluidics community of electrokinetics research has led to a sequel to the first Electrokinetic Phenomena and Microfluidics session at the 82nd ACS Colloid and Surface Science Symposium in Raleigh, NC, in 2008, and which we hope will now be a regular feature at successive ACS Colloid and Surface Science meetings. This year at the combined 2009 13th International Conference on Surface and Colloid Science (ICSCS) and the 83rd ACS Colloid and Surface Science Symposium in New York, the Electrokinetics and Microfluidics symposium proved to be extremely popular, with three keynote lectures presented by Professor Howard Stone, Professor Hsueh-Chia Chang, and Professor Thomas Healy, and 44 oral presentations. In both 2008 and 2009, Biomicrofluidics has organized a special issue to cover some of the contributions reported at these meetings.²The growing interest in using electric fields to manipulate biological entities such as cells, DNA, and even single molecules is reflected in this year’s collection of papers with dielectrophoretic (DEP) phenomena comprising the bulk of the contributions. In Ref. ³, a new theory to describe Stern layer conductance along the surface of nanocolloids is proposed, forming the basis for the derivation of a more accurate prediction of the DEP crossover frequency. This theory is then employed to determine the conformation and, hence, optimum coverage of oligonucleotides on the surface of nanocolloid functionalized molecular probes during DNA hybridization under the influence of DEP, which can be exploited for biomolecular sensing. Other fundamental DEP papers include the investigation of particle motion under DEP induced optically via a photoconductor, in which Zhu et al.⁴ characterized the frequency dependence of the motion through the synchronous velocity spectra of the particles, and a numerical study of particle trapping at the throat of converging-diverging microchannels under the influence of negative DEP using a transient arbitrary Lagrangian–Eulerian finite element method.⁵ A more practical implementation is, on the other hand, reported by Yang et al.⁶ in which the negative DEP is exploited to separate colorectal cancer cells from other cells in a microfluidic device as a demonstration of a portable cancer detection tool.Continuing along the separation theme, but with regard to DNA separation using pulsed-field gel electrophoresis aided by sparse but regularly ordered microfabricated arrays of nanoposts, is a Brownian dynamics simulation model reported by Ou et al.⁷ in which DNA channeling, which predicts that the motion of DNA is undisturbed by the presence of arrays for large spacing to DNA equilibrium size ratios and when the field lines are straight, is predicted, consistent with experimental observations. In another fundamental paper, a direct numerical simulation model is presented to predict the current-voltage relationship across conducting pores along cell membranes, which is of fundamental importance in the electroporation process.⁸We hope that you will enjoy reading the contributions in this special topic and that it encourages you to participate in future Electrokinetics and Microfluidics meetings at the ACS Colloid and Surface Science Symposia, which we definitely hope will continue on a regular basis.     

Preface to Special Topic: Selected Papers from the 5th International Conference on Optofluidics

The 5th International Conference on Optofluidics (Optofluidics 2015) was held in Taipei, Taiwan, July 26–29, 2015. The aim of this conference was to provide a forum to promote scientific exchange and to foster closer networks and collaborative ties between leading international researchers in optics and micro/nanofluidics across various disciplines. The scope of Optofluidics 2015 was deliberately broad and interdisciplinary, encompassing the latest advances and the most innovative developments in micro/nanoscale science and technology. Topics ranged from fundamental research to its applications in chemistry, physics, biology, materials, and medicine.Approximately 300 delegates participated in Optofluidics 2015 from across the globe, including Australia, Canada, China, France, Germany, Hong Kong, India, Japan, Korea, Singapore, Taiwan, UK, and USA. In total, 242 presentations were arranged, including 10 plenary speeches, 27 keynote speeches, 65 invited talks, 33 contributed talks, and 107 poster presentations. This collection of twelve papers on this special topic spans both the fundamentals and the frontier applications of this interdisciplinary research field.Optical measurements of particle or flow and fluidic manipulation for optical applications were presented. Lin and Su¹ reported a novel method to measure the depth position of rapidly moving objects inside a microfluidic channel based on the chromatic aberration effect; the depth positions of label-free particles of diameter as small as 2 μm and erythrocytes of concentration 2 × 10³ cells/μl and velocity 2.78 mm/s were detected within a range ±25 μm in a simple and inexpensive manner. Sun and Huang² demonstrated the use of a microscopic circular polariscope to measure the flow-induced birefringence in a microfluidic device that represents the kinematics of fluid motion optically; CTAB:NaSal, CPyCl:NaSal, and CPyCl:NaSal:NaCl solutions were used to investigate the strain rate and the results were compared with the μPIV diagnosis. He et al.³ studied the fundamentals, especially the thinning and opening of the oil film within each pixel of an electrowetting display; to achieve repeatable oil movement and the resulting pixel performance, a new method to fill each pixel with a controllable oil volume using an oil-droplet emulsion created with a microfluidic device was demonstrated.This special topic includes papers also on particle manipulation. Weng et al.⁴ evaluated the size-dependent crossing frequency of dielectrophoretically driven particles; numerical simulation using a Maxwell stress tensor and a finite element method was reported to assess the size effect. In addition to electric manipulation, magnetic driving of the particles was demonstrated. Ido et al.⁵ examined microswimmers of magnetic particle chains in an oscillating magnetic field experimentally and analyzed numerically with a lattice Boltzmann method, an immersed boundary method, and a discrete particle method based on simplified Stokesian dynamics. Huang et al.⁶ described a technique to manipulate magnetic beads and achieved a great washing efficiency with zero bead loss using an appropriate electrode design and channel height of a digital microfluidic immunoassay; a model immunoassay of human soluble tumor necrosis factor receptor I (sTNF-RI) was performed to offer an improved limit of detection (3.14 pg/ml) with a small number of magnetic beads (25 beads), decreased reagent volumes (200 nl), and decreased duration of analysis (<1 h). Chiu et al.⁷ reported particle separation using cross-flow filtration enhanced with hydrodynamic focusing; label-free separation of particles of diameters 2.7 and 10.6 μm at a sample throughput 10 μl/min was performed; separation of spiked human prostate cancer cell lines (PC3) cells in whole blood was also demonstrated.Chemical sensors and biosensors are covered in this special topic. Cheng et al.⁸ measured the chemical compounds in third-hand smoke on varied clothing fibres with an analytical balance, or nicotine and 3-ethenylpyridine (3-EP) with a surface-acoustic-wave sensor composed of coated oxidized hollow mesoporous carbon nanospheres. Pu et al.⁹ described a continuous glucose monitoring microsystem consisting of a three-electrode electrochemical sensor in which the working electrode (WE) was covered with a single layer of graphene and gold nanoparticles to improve the sensor performance; the results of glucose measurement were linear below concentration 162 mg/dl with a detection limit 1.44 mg/dl. Li et al.¹⁰ implemented a microfluidic device measuring the glucose concentration with integrated fibre-optic surface plasmon resonance sensor and electrode pairs for volume quantification.Implantable devices and microneedles for drug delivery and liquid transport are addressed in this special topic. Zhang et al.¹¹ reported a flexible polyimide device seated under rabbit eyelids to deliver drug by iontophoresis; varied currents to release manganese ions (Mn²⁺) as tracers were investigated; the thermal effect on application of a current was studied. Lee et al.¹² presented a disposable Parylene microneedle array of large aspect ratio that vibrated with a piezoelectric actuator to mimic the vibrating motion of a mosquito''s proboscis and to decrease the insertion force by 40%. Song et al.¹³ demonstrated microinjection into a model organism, Caenorhabditis elegans (C. elegans) on an automated device capable of loading, immobilization, injection, and sorting; with 200 worms studied, injection speed 6.6 worm/min, injection success rate 77.5%, and sorting success rate 100% were obtained.We express our gratitude for the financial support from Ministry of Science and Technology (Taiwan), Bureau of Foreign Trade (Taiwan), National Taiwan University and Research Center for Applied Sciences of Academia Sinica, and for administrative support from Instrument Technology Research Center in making Optofluidics 2015 a successful conference. Our acknowledgements include Leslie Yeo, Frederick Kontur, Christine Urso, and all staff from Biomicrofluidics for their kind assistance during the preparation, and, most importantly, all authors who have contributed their work for this special topic.     

Preface to Special Topic: Papers from the 2009 Conference on Advances in Microfluidics and Nanofluidics, The Hong Kong University of Science & Technology, Hong Kong, 2009

The inaugural conference on Advances in Microfluidics and Nanofluidics was held at the Hong Kong University of Science and Technology on 5–7 January 2009 and brought together leading researchers from across a wide variety of disciplines from North America, Europe, Asia, and Oceania. This Special Topic section forms the second of the two issues dedicated to original contributions covering both fundamental physicochemical aspects of microfluidics and nanofluidics as well as their applications to the miniaturization of chemical and biological systems that were presented at the conference.In the last five years, we have observed rapid growth in the microfluidics and nanofluidics community in Asia, owing largely to the substantial strategic investments by both government and industry in the region to promote the microfabrication and nanotechnology sectors.¹ The organization of a regular meeting focusing on activities in the Asia-Pacific rim region was, therefore, timely, particularly to enhance dissemination of research of the highest quality within the region and to promote collaboration between researchers in the Asian community with their counterparts from Europe and the USA.Biomicrofluidics is, therefore, proud to be closely involved with the organization of the first of such conferences, Advances in Microfluidics and Nanofluidics 2009, which was kindly hosted by the Hong Kong University of Science and Technology (HKUST). As reported in the preface to the first of the two issues dedicated to invited reviews and original contributions associated with the conference,² the meeting, which took place over three days in the breathtaking HKUST campus overlooking Clearwater Bay in Hong Kong, was a tremendous success. Together with our colleagues, the Biomicrofluidics editors are busy putting in place arrangements for a follow-up meeting in January 2011. Given the overwhelming response and positive feedback we’ve had to date, we believe that Advances in Microfluidics and Nanofluidics will form a regular event in the calendar of the Asian microfluidics and nanofluidics community in the future.It was particularly pleasing to observe the translation of fundamental and theoretical work into advanced applied chip-based platforms for a variety of practical chemical and biological applications in the talks presented at the conference. The collection of articles in this second part, in fact, provides a gist of the flavor of the multidisciplinary research spanning the entire fundamental to applied research spectrum, which is exactly the scope which the journal intends to cover.Electrokinetics continues to be a dominant theme in this issue and within the microfluidics and nanofluidics community. The article by Ng et al.³ provides experimental evidence that might put to rest a longstanding area of debate within the electrokinetics community on the role of Faradaic charging in driving electro-osmotic flow, first proposed by Ben and Chang.⁴ In other electrokinetics papers, the role of interfaces is explored, for example, electrowetting on the superhydrophobic nanostructured surfaces of a lotus leaf⁵ and droplet manipulation in an immiscible dielectric liquid continuum under an electric field.⁶In addition, the characterization of the surface charge density of the nanopores etched in organic foils is reported by Xue et al.,⁷ which provides a deeper understanding of the mechanisms by which ions are transported in nanochannels, whereas Wei and Hsiao⁸ present a stochastic simulation to model the condensation of linear polyelectrolyte molecules under electric fields, in which they show the marked increase in the mobility of the polyelectrolyte chain during its unfolding in free-solution electrophoresis.Continuing along the theme of numerical simulations, particulate transport in converging-diverging microchannels was studied using a Lagrangian-Eulerian finite-element model,⁹ and slip arising in Couette flows over superhydrophobic surfaces was studied using a hybrid multiscale simulation that interfaces molecular dynamics simulations in the near-wall region with the continuum fluid model in the bulk.¹⁰ In other numerical studies, drop coalescence¹¹ and nanotube transport¹² were studied.Complementing these fundamental studies is the use of multiphase flows in microfluidic channels to engineer scaffolds for tissue engineering in which the bubbles trapped in liquid droplets transported in microchannels were employed to produced the pores of the scaffold.¹³ Other practical microfluidics applications, such as chip-based enhancement of DNA hybridization through a genetic-bead-based protocol¹⁴ and an automated ELISA chip for chemical-biological analysis with an enhancement in the detection range and time,¹⁵ also constitute papers in this Special Topic section.We hope you enjoy reading the papers in this Special Topic section and that it provides you with a feel for the broad multidisciplinary spectrum across fundamental and applied microfluidic and nanofluidic research that the conference, as well as the journal, intends to span. Do watch out for the conference announcement for the next Advances in Microfluidics and Nanofluidics meeting in 2011 on the Biomicrofluidics website (http://bmf.aip.org)—hope to see you there!     

Preface to Special Topic: Microfluidics in cell biology and tissue engineering

In this special issue of Biomicrofluidics, a wide variety of applications of microfluidics to tissue engineering and cell biology are presented. The articles illustrate the benefits of using microfluidics for controlling the cellular environment in a precise yet high rate manner using minimum reagents. The topic is very timely and takes a stab at portraying a glimpse of what is to come in this exciting and emerging field of research.     

Preface to Special Topic: Microsystems for manipulation and analysis of living cells

This Preface describes exciting papers contributed to the Special Topic section on manipulation and analysis of cells using microsystems. Brief summaries of each paper are provided and general trends are discussed.     

Preface to Special Topic: Biological microfluidics in tissue engineering and regenerative medicine

In this special issue of Biomicrofluidics, many manifestations of biological microfluidics have been highlighted that have significance to regenerative biology and medicine. The collated articles demonstrate the applicability of these biological microfluidics for studying a wide range of biomedical problems most useful for understanding and shining light on basic biology to those applications relevant to clinical medicine.     

2004～2008年我国情报专题研究高被引论文的统计与分析

对2004～2008年国内情报专题研究论文被引用情况进行了统计与分析.2004～2008年情报专题研究被引论文共1 479篇,总被引频次为4 799次,篇均被引频次为3.24.利用普辅斯定律(N=0.749×√nmax)确定核心作者的方法确定高被引论文.论文最高被引频次为44次,nmax=44,确定被引频次≥5的论文为高被引论文.高被引论文共299篇,被引频次是2 687,其中被引用≥20次的论文共16篇.发表高被引论文最多的期刊依次为<情报杂志>(40篇)、<现代情报>(32篇)、<情报科学>(31篇)、<情报学报>(24篇)、<情报理论与实践>(24篇)等.对299篇的高被引论文的作者分布、年代分布、地区分布、机构分布、主题分布等进行了详细的统计和分析.     

学会青少年教育及科普探索——以国外化学会为例

随着科技进步,以推进学术发展为目的学会组织职能不断扩展,大众科学传播、社会服务、青少年教育等科普行为已成为学会的重要工作,国外先进学会在这一领域建立和完善了管理体制机制。该文通过对美、英、德、日、韩、法化学会科普案例展开调研,介绍国外做法,总结经验,助力我国化学会及学会组织开展科普工作。     

基于SSCI的2000-2010年我国大陆信息科学和图书馆学论文的计量分析

通过对十年来(2000-2010)SSCI收录的信息科学和图书馆学的66种期刊中的中国大陆学者发表的455篇论文进行计量分析,包括各年文献量、期刊、著者、机构、研究主题和引文等,以期从一个侧面来反映我国大陆学者在信息科学和图书馆学研究方面的科研生产量、核心期刊、核心人员、核心机构、主要的研究领域和国际影响力等信息,便于人们通过定量数据了解我国大陆信息科学和图书馆学研究的现状和实力。     

2000-2003年图书馆学、情报学与文献学国家级项目立项分析

本文统计了 2 0 0 0年至 2 0 0 3年 4年间图书馆学、情报学与文献学研究项目在国家社会科学基金等 7个国家级基金项目中的立项情况 ,包括立项项目、申报机构、研究人员、主要研究方向等 ,并以武汉大学信息管理学院等为例 ,总结了有效提升科研竞争力 ,争取科研立项成功的 3个因素。     

科学学领域作者合作网络分析 ——以《科研管理》（2004-2008）为例

摘要：合作发表论文对于资源共享、思想交流、知识传播、信息获取等方面都具有重要的意义。本文收集并整理了2004到2008年《科研管理》的作者合作情况,构建了作者合作网络。然后,利用社会网络分析方法（SNA）对整个合作网络进行了小团体分析、集聚程度分析和中心性分析。结果显示,(1)整体网络是连通的,(2)小合作团体的规模都较小,(3)整体网络和小团体网络均具有无标度网络特征。