Comparative studies on the analysis of glycoproteins and lipopolysaccharides by the gel-based microchip and SDS-PAGE

In order to determine time efficiency between the gel-based microchip (LabChip) and traditional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), glycoproteins and lipopolysaccharides were analyzed in this study. After 90 min of gel electrophoresis, glycoproteins (bovine serum albumin, lysozyme, ovalbumin, and apo-transferrin) and fluorescent lipopolysaccharides (LPS-O and LPS-S) under reducing conditions could be analyzed by SDS-PAGE, and it would take (including imaging and analyzing) more than 3 h. The same sample could also be assayed on a Bioanalyzer in combination with the LabChip, and it would only need 30 min from start to finish. The assay software automatically calculated the size and concentration of each separated peak and displayed the results in real time, thus eliminating time-consuming procedures such as imaging and analyzing. Compared to the traditional reducing SDS-PAGE, LabChip has a faster turnaround time.     

Density-dependent separation of encapsulated cells in a microfluidic channel by using a standing surface acoustic wave

This study presents a method for density-based separation of monodisperse encapsulated cells using a standing surface acoustic wave (SSAW) in a microchannel. Even though monodisperse polymer beads can be generated by the state-of-the-art technology in microfluidics, the quantity of encapsulated cells cannot be controlled precisely. In the present study, mono-disperse alginate beads in a laminar flow can be separated based on their density using acoustophoresis. A mixture of beads of equal sizes but dissimilar densities was hydrodynamically focused at the entrance and then actively driven toward the sidewalls by a SSAW. The lateral displacement of a bead is proportional to the density of the bead, i.e., the number of encapsulated cells in an alginate bead. Under optimized conditions, the recovery rate of a target bead group (large-cell-quantity alginate beads) reached up to 97% at a rate of 2300 beads per minute. A cell viability test also confirmed that the encapsulated cells were hardly damaged by the acoustic force. Moreover, cell-encapsulating beads that were cultured for 1 day were separated in a similar manner. In conclusion, this study demonstrated that a SSAW can successfully separate monodisperse particles by their density. With the present technique for separating cell-encapsulating beads, the current cell engineering technology can be significantly advanced.     

国家科技计划及项目管理中的"二八"现象和长尾理论的影响浅析

"二八"定律对科技管理有很大的影响,使科技计划管理和科技项目管理中普遍存在"二八"现象.长尾理论是网络时代兴起的一种新理论,它强调的是要重视小主体的作用和影响.分析我国科技管理中"二八"现象和长尾效应,思考长尾效应对我国科技管理的影响,提出"二八"定律和长尾理论下我国科技计划管理工作的有关建议,将有助于构建基于全生命周期的科技计划管理模式,完善科技计划管理体系.     

国家科技计划及项目管理中的“二八”现象和长尾理论的影响浅析

 “二八”定律对科技管理有很大的影响,使科技计划管理和科技项目管理中普遍存在“二八”现象。长尾理论是网络时代兴起的一种新理论,它强调的是要重视小主体的作用和影响。分析我国科技管理中“二八”现象和长尾效应,思考长尾效应对我国科技管理的影响,提出“二八”定律和长尾理论下我国科技计划管理工作的有关建议,将有助于构建基于全生命周期的科技计划管理模式,完善科技计划管理体系。     

仿真软件在电路分析实验教学中的应用效果初探

传统的电路分析实验课程由于学时、教学资源的限制存在种种问题。文章结合教学实践,总结并阐述了在电路分析实验课程中利用仿真软件开展虚拟实验的教学效果。     

黄河宁蒙河段水文-水温过程和河道形态变化对凌汛的影响

黄河宁蒙河段的水文和水温过程近几十年来发生了显著变化,迫切需要评估这一变化对河道形态、凌汛的影响及其可能的致灾效应。利用同水位河道过水断面形态参数分析方法,选取宁蒙河段稳定封冻区域（石嘴山-头道拐）的石嘴山、磴口、巴彦高勒、三湖河口和头道拐5个主要水文站,根据2008-2013年凌汛前实测断面资料,计算相应年份5个水文站同水位下的河道断面面积、平均水深和深泓点高程。结果表明,宁蒙河段近年来凌汛期的径流量和水温呈现逐渐增大的趋势,下泄流量过程有助于减少凌灾发生的几率;各水文站凌汛前的断面面积和平均水深等断面形态参数呈逐年增大的趋势,深泓点高程不断降低。河道过水断面形态的这种变化增大了凌汛期河道的过流能力,有助于缓解开河期可能出现的凌汛灾情。     

Blood viscoelasticity measurement using steady and transient flow controls of blood in a microfluidic analogue of Wheastone-bridge channel

Accurate measurement of blood viscoelasticity including viscosity and elasticity is essential in estimating blood flows in arteries, arterials, and capillaries and in investigating sub-lethal damage of RBCs. Furthermore, the blood viscoelasticity could be clinically used as key indices in monitoring patients with cardiovascular diseases. In this study, we propose a new method to simultaneously measure the viscosity and elasticity of blood by simply controlling the steady and transient blood flows in a microfluidic analogue of Wheastone-bridge channel, without fully integrated sensors and labelling operations. The microfluidic device is designed to have two inlets and outlets, two side channels, and one bridge channel connecting the two side channels. Blood and PBS solution are simultaneously delivered into the microfluidic device as test fluid and reference fluid, respectively. Using a fluidic-circuit model for the microfluidic device, the analytical formula is derived by applying the linear viscoelasticity model for rheological representation of blood. First, in the steady blood flow, the relationship between the viscosity of blood and that of PBS solution (μ_Blood/μ_PBS) is obtained by monitoring the reverse flows in the bridge channel at a specific flow-rate rate (Q_PBS^SS/Q_Blood^L). Next, in the transient blood flow, a sudden increase in the blood flow-rate induces the transient behaviors of the blood flow in the bridge channel. Here, the elasticity (or characteristic time) of blood can be quantitatively measured by analyzing the dynamic movement of blood in the bridge channel. The regression formula (A_Blood (t) = A_α + A_β exp [−(t − t₀)/λ_Blood]) is selected based on the pressure difference (ΔP = P_A − P_B) at each junction (A, B) of both side channels. The characteristic time of blood (λ_Blood) is measured by analyzing the area (A_Blood) filled with blood in the bridge channel by selecting an appropriate detection window in the microscopic images captured by a high-speed camera (frame rate = 200 Hz, total measurement time = 7 s). The elasticity of blood (G_Blood) is identified using the relationship between the characteristic time and the viscosity of blood. For practical demonstrations, the proposed method is successfully applied to evaluate the variations in viscosity and elasticity of various blood samples: (a) various hematocrits form 20% to 50%, (b) thermal-induced treatment (50 °C for 30 min), (c) flow-induced shear stress (53 ± 0.5 mL/h for 120 min), and (d) normal rat versus spontaneously hypertensive rat. Based on these experimental demonstrations, the proposed method can be effectively used to monitor variations in viscosity and elasticity of bloods, even with the absence of fully integrated sensors, tedious labeling and calibrations.     

Discrimination between the human prostate normal cell and cancer cell by using a novel electrical impedance spectroscopy controlling the cross-sectional area of a microfluidic channel

The prostate biopsy method shows a high false negative result because the suspicious tissue considered as cancer is not confirmed during tissue sampling. Thus, repeated biopsy procedures and diagnostic errors in relation to prostate cancer frequently occur. The purpose of this research is to enhance the prostate cancer detection rate by using microfluidic electrical impedance spectroscopy (μEIS), which allows real-time measurement of the electrical impedance of a single human prostate normal cell and cancer cell. The μEIS was equipped with a movable flexible membrane, which is operated by pneumatic pressure to capture the single cell on the surface of sensing electrodes. The forced tight contact between the cell and electrodes makes it possible to measure the electrical characteristics of the cell with a high sensitivity. The μEIS discriminates well between normal human prostate cells (RWPE-1) and cancer cells (PC-3) at 8.7 kHz based on the electrical signal responses of the cells. The average difference rates of admittance magnitude and susceptance are 54.55% and 54.59%, respectively. The developed μEIS also shows high repeatability, which was verified by a deionized water test conducted before and after each cell assay; the maximum variance of both the impedance and admittance at 8.7 kHz was as small as 9.48%.     

Which similarity measure to use in network analysis: Impact of sample size on phi correlation coefficient and Ochiai index

Some networks are explicit where members make direct connections (e.g. Facebook network), whereas other networks are implicit (e.g. co-citation network) in which an edge between two nodes is inferred using a similarity index. Choosing the right index to infer connections in an implicit/inferred network is important because conclusions can be biased if a network does not represent true relationships. In this study, we compared two indexes: Phi Correlation Coefficient (PCC) and Ochiai Coefficient (Och) based on their sensitivity to the sample size of transactions from where the network is inferred. For demonstration, we used an implicit network, called a comorbidity network, developed from health records of 22.1 million patients. The networks were compared based on their overall topologies and node centralities. Results showed that the network formed using Och was more robust to the sample size than PCC. The network using Och followed a small-world topology irrespective of the sample size whereas the structure of a network using PCC was inconsistent. Regarding node centralities, the betweenness centrality was most affected by the sample size. Our results lead us to recommend Och over PCC.     

流动人口归属感、社会支持对主观幸福感的作用机制研究——以北京市为例

流动人口的产生是我国城镇化发展的必然结果。作为一个游离在城市市民边缘的特殊群体,一直备受社会关注,如何使流动人口更好的融入城市,将成为城市建设与构建和谐社会的重要议题。研究对流动人口的归属感、社会支持和主观幸福感进行了分析。研究结果显示,社会支持对主观幸福感有显著性影响;另外,验证了流动人口的归属感在社会支持和主观幸福感之间的中介作用,结果为提升流动人口主观幸福感提供了理论参考。     

The effects of different syringe volume, needle size and sample volume on blood gas analysis in syringes washed with heparin

Introductıon:

We evaluated the effect of different syringe volume, needle size and sample volume on blood gas analysis in syringes washed with heparin.

Materials and methods:

In this multi-step experimental study, percent dilution ratios (PDRs) and final heparin concentrations (FHCs) were calculated by gravimetric method for determining the effect of syringe volume (1, 2, 5 and 10 mL), needle size (20, 21, 22, 25 and 26 G) and sample volume (0.5, 1, 2, 5 and 10 mL). The effect of different PDRs and FHCs on blood gas and electrolyte parameters were determined. The erroneous results from nonstandardized sampling were evaluated according to RiliBAK’s TEa.

Results:

The increase of PDRs and FHCs was associated with the decrease of syringe volume, the increase of needle size and the decrease of sample volume: from 2.0% and 100 IU/mL in 10 mL-syringe to 7.0% and 351 IU/mL in 1 mL-syringe; from 4.9% and 245 IU/mL in 26G to 7.6% and 380 IU/mL in 20 G with combined 1 mL syringe; from 2.0% and 100 IU/mL in full-filled sample to 34% and 1675 IU/mL in 0.5 mL suctioned sample into 10 mL-syringe. There was no statistical difference in pH; but the percent decreasing in pCO₂, K⁺, iCa²⁺, iMg²⁺; the percent increasing in pO₂ and Na⁺ were statistical significance compared to samples full-filled in syringes. The all changes in pH and pO₂ were acceptable; but the changes in pCO₂, Na⁺, K⁺ and iCa²⁺ were unacceptable according to TEa limits except fullfilled-syringes.

Conclusions:

The changes in PDRs and FHCs due nonstandardized sampling in syringe washed with liquid heparin give rise to erroneous test results for pCO₂ and electrolytes.     

The characterization of four gene expression analysis in circulating tumor cells made by Multiplex-PCR from the AdnaTest kit on the lab-on-a-chip Agilent DNA 1000 platform

Introduction

Nowadays, on-a-chip capillary electrophoresis is a routine method for the detection of PCR fragments. The Agilent 2100 Bioanalyzer was one of the first commercial devices in this field. Our project was designed to study the characteristics of Agilent DNA 1000 kit in PCR fragment analysis as a part of circulating tumour cell (CTC) detection technique. Despite the common use of this kit a complex analysis of the results from a long-term project is still missing.

Materials and methods

A commercially available Agilent DNA 1000 kit was used as a final step in the CTC detection (AdnaTest) for the determination of the presence of PCR fragments generated by Multiplex PCR. Data from 30 prostate cancer patients obtained during two years of research were analyzed to determine the trueness and precision of the PCR fragment size determination. Additional experiments were performed to demonstrate the precision (repeatability, reproducibility) and robustness of PCR fragment concentration determination.

Results

The trueness and precision of the size determination was below 3% and 2% respectively. The repeatability of the concentration determination was below 15%. The difference in concentration determination increases when Multiplex-PCR/storage step is added between the two measurements of one sample.

Conclusions

The characteristics established in our study are in concordance with the manufacturer’s specifications established for a ladder as a sample. However, the concentration determination may vary depending on chip preparation, sample storage and concentration. The 15% variation of concentration determination repeatability was shown to be partly proportional and can be suppressed by proper normalization.Key words: lab-on-a-chip devices, capillary electrophoresis, multiplex PCR, circulating tumour cells, Agilent DNA 1000 kit     

西部地区新型工业化质量测度及空间溢出效应

本文基于2008-2017年间的西部11个省域的面板数据为研究对象,对新型工业化质量进行测度与评价,探究西部地区新型工业化质量发展的空间依赖性及影响因素的时空作用机制。结果显示：①在只考虑地理距离的空间关系下,西部地区新型工业化质量的空间分布呈现着高—高集聚与高—低极化的趋势,形成演化空间差异相对明显的空间格局。②影响西部地区新型工业化质量发展的因素存在着空间溢出效应。资源、开放度、技术因素对西部区域新型工业化质量发展起到促进作用,资本、劳动力、政府规模阻碍了西部工业化质量的提高。西部地区应因地制宜实施生态评估机制与产业政策布局,合理进行人力资本、信息技术与基础设施的投入与建设,利用空间溢出效应实施生态导向的目标责任制。提高生态系统的承载力,放慢经济增长的速度,提升工业化的质量型绩效水平,实现西部地区新型工业化高质量发展的空间格局。     

中国物流业技术效率差异及其影响因素研究——基于省级面板数据的实证分析

以1991~2007年中国大陆29个省级地区面板数据为基础,采用外生性影响因素与随机前沿生产函数模型联合估计的方法(SFA一步法),测算了中国各地区物流业技术效率,考察了人力资本、制度、政府干预、开放程度及产业结构等环境因素对物流业技术效率的影响。主要发现有:考察期间中国物流业技术效率仍处于较低水平,地区间存在差异,且在扩大;政府干预、国有率阻碍技术效率提升,但负面影响在减小;人力资本、开放程度促进技术效率提升,但由于二者存在交互影响使得它们对物流效率的作用在中、西部地区明显弱于东部地区;"西部大开发"战略的实施,使得产业结构调整对该地区物流效率的促进作用变为显著;就物流发展环境而言,中部地区存在"塌陷"现象;改善物流环境对促进地区协调发展有重要意义。     

Increased density and coverage uniformity of viruses on a sensor surface by using U-type, T-type, and W-type microfluidic devices

Microorganisms, molecules, or viruses in the fluidic environment are usually at considerably low Reynolds numbers because of small diameters. The viscous forces of molecules and viruses dominate at considerably low Reynolds numbers. This study developed three microfluidic devices, that is, T type, U type, and W type devices, to control the flow movement, which can increase the adhesion density of viruses on the surface of the sensor. The linker 11-mercaptoundecanoic acid (11-MUA) and Turnip yellow mosaic virus (TYMV) were used in this study and measured by a confocal microscope. Fluorescent intensity and coverage of 11-MUA and TYMV were used to identify the adhesion density quantitatively. Results indicate that 11-MUA layers and TYMV disperse randomly by the dipping method. Attachment tests for T-, U-, and W-type devices demonstrated average fluorescence intensities of 1.56, 2.18, and 2.67, respectively, and average fluorescence coverage of 1.31, 1.87, and 2.55 times those of dipping techniques, respectively. The T-type device produced the lowest fluorescence coverage uniformity (10%-80%), whereas the W-type device produced the highest fluorescence coverage uniformity (80%-90%). Fluorescence intensity correlates positively with flow within a specified flow range; however, the exact relationship between fluorescence intensity and flow requires further study. Attachment tests for TYMV virus samples indicated that the W-type device produced an average fluorescence intensity of 3.59 and average fluorescence coverage of 19.13 times greater than those achieved through dipping techniques. Traditional immersion methods achieved fluorescence coverage of 0%-10%, whereas that of the W-type device reached 70%-90%.     

中国碳排放增长的多层递进动因——基于SDA和SPD的实证研究

研究碳排放增长的多维、多层动因,识别关键的增排产业链和增排路径,对于宏观减排政策制定和微观减排路径选择都具有较强的现实意义。本文基于非竞争型投入产出模型,利用结构分解和结构路径分解的分析方法,从总体、生产阶段、产业链3个层次对中国碳排放增长进行了递阶分解分析,识别出了2010—2015年中国碳排放增长的主要动因和路径。研究结论表明：①需求规模变化是中国总体、生产阶段、产业链碳排放增加的主导影响因素;②煤炭消费发挥着减排作用且贡献巨大,但其他能源的增排效应使煤炭的减排贡献大打折扣;③能源效率变化对各生产阶段的影响为正且呈递减趋势,最终需求结构变化对第一生产阶段的碳排放具有显著减排效应,对其他生产阶段具有轻微增排效应;④需求规模变化和直接消耗系数变化是多数增排产业链的最大影响因素,30条增排路径占中国2010—2015年碳排放增加量的25.7%,构成了碳排放增加的关键路径和动因。最后,从宏观和微观两方面提出了相应的减排政策建议。     

基于状况空间模型的我国科技发展的财政金融政策效应研究

 本文运用状态空间模型对1990-2008年我国科技发展的财政金融政策效应进行了实证分析,结果表明：财政科技支出和金融科技贷款对我国科技发展的弹性系数呈现出明显的阶段性特征,并且这种阶段性特征变化与国家科技财政政策和金融政策的变化具有十分密切的关系。因此今后政府应进一步制定相关财政政策和金融政策以推动我国科技的进一步发展和我国创新型国家建设。     

我国OLED产业专利战略研究

OLED是20世纪中期发展起来的一种新型显示技术,在新兴的平板显示领域,OLED将是未来显示行业的明星,有着巨大的市场发展潜力和空间。本文分析了OLED基础专利的许可态势,并在此基础上研究了我国OLED行业专利工作存在的问题以及专利发展的策略。     

The effect of red blood cell aggregation on velocity and cell-depleted layer characteristics of blood in a bifurcating microchannel

Red blood cell (RBC) aggregation is a multifaceted phenomenon, and whether it is generally beneficial or deleterious remains unclear. In order to better understand its effect on microvascular blood flow, the phenomenon must be studied in complex geometries, as it is strongly dependent on time, flow, and geometry. The cell-depleted layer (CDL) which forms at the walls of microvessels has been observed to be enhanced by aggregation; however, details of the characteristics of the CDL in complex regions, such as bifurcations, require further investigation. In the present study, a microchannel with a T-junction was used to analyze the influence of aggregation on the flow field and the CDL. Micro-PIV using RBCs as tracers provided high resolution cell velocity data. CDL characteristics were measured from the same data using a newly developed technique based on motion detection. Skewed and sharpened velocity profiles in the daughter branches were observed, contrary to the behavior of a continuous Newtonian fluid. RBC aggregation was observed to increase the skewness, but decrease the sharpening, of the velocity profiles in the daughter branches. The CDL width was found to be significantly greater, with a wider distribution, in the presence of aggregation and the mean width increased proportionally with the reciprocal of the fraction of flow entering the daughter branch. Aggregation also significantly increased the roughness of the interface between the CDL and the RBC core. The present results provide further insight into how RBC aggregation may affect the flow in complex geometries, which is of importance in both understanding its functions invivo, and utilizing it as a tool in microfluidic devices.