DNA-library assembly programmed by on-demand nano-liter droplets from a custom microfluidic chip     

Uwe Tangen  Gabriel Antonio S. Minero  Abhishek Sharma  Patrick F. Wagler  Rafael Cohen  Ofir Raz  Tzipy Marx  Tuval Ben-Yehezkel  John S. McCaskill 《Biomicrofluidics》2015,9(4)

Nanoscale synthetic biology can benefit from programmable nanoliter-scale processing of DNA in microfluidic chips if they are interfaced effectively to biochemical arrays such as microwell plates. Whereas active microvalve chips require complex fabrication and operation, we show here how a passive and readily fabricated microchip can be employed for customizable nanoliter scale pipetting and reaction control involving DNA. This recently developed passive microfluidic device, supporting nanoliter scale combinatorial droplet generation and mixing, is here used to generate a DNA test library with one member per droplet exported to addressed locations on microwell plates. Standard DNA assembly techniques, such as Gibson assembly, compatible with isothermal on-chip operation, are employed and checked using off-chip PCR and assembly PCR. The control of output droplet sequences and mixing performance was verified using dyes and fluorescently labeled DNA solutions, both on-chip and in external capillary channels. Gel electrophoresis of products and DNA sequencing were employed to further verify controlled combination and functional enzymatic assembly. The scalability of the results to larger DNA libraries is also addressed by combinatorial input expansion using sequential injection plugs from a multiwell plate. Hence, the paper establishes a proof of principle of the production of functional combinatorial mixtures at the nanoliter scale for one sequence per well DNA libraries.  相似文献   

Two-dimensional spatial manipulation of microparticles in continuous flows in acoustofluidic systems     

Lu Gao  C. Wyatt Shields  IV  Leah M. Johnson  Steven W. Graves  Benjamin B. Yellen  Gabriel P. López 《Biomicrofluidics》2015,9(1)

We report a modeling and experimental study of techniques to acoustically focus particles flowing through a microfluidic channel. Our theoretical model differs from prior works in that we solve an approximate 2-D wave transmission model that accounts for wave propagation in both the solid and fluid phases. Our simulations indicate that particles can be effectively focused at driving frequencies as high as 10% off of the resonant condition. This conclusion is supported by experiments on the acoustic focusing of particles in nearly square microchannels, which are studied for different flow rates, driving frequencies and placements of the lead zirconate titanate transducer, either underneath the microchannel or underneath a parallel trough. The relative acoustic potential energy and the resultant velocity fields for particles with positive acoustic contrast coefficients are estimated in the 2-D limit. Confocal microscopy was used to observe the spatial distribution of the flowing microparticles in three dimensions. Through these studies, we show that a single driving frequency from a single piezoelectric actuator can induce the 2-D concentration of particles in a microchannel with a nearly square cross section, and we correlate these behaviors with theoretical predictions. We also show that it is possible to control the extent of focusing of the microparticles, and that it is possible to decouple the focusing of microparticles in the vertical direction from the lateral direction in rectangular channels with anisotropic cross sections. This study provides guidelines to design and operate microchip-based acoustofluidic devices for precise control over the spatial arrangement of microparticles for applications such as flow cytometry and cellular sorting.  相似文献   

A computer science and robotics integration model for primary school: evaluation of a large-scale in-service K-4 teacher-training program     

El-Hamamsy  Laila  Chessel-Lazzarotto  Frédérique  Bruno  Barbara  Roy  Didier  Cahlikova  Tereza  Chevalier  Morgane  Parriaux  Gabriel  Pellet  Jean-Philippe  Lanarès  Jacques  Zufferey  Jessica Dehler  Mondada  Francesco 《Education and Information Technologies》2021,26(3):2445-2475

Education and Information Technologies - Integrating computer science (CS) into school curricula has become a worldwide preoccupation. Therefore, we present a CS and Robotics integration model and...  相似文献   

Sport und Doping     

Gabriel Duttler 《Sportwissenschaft》2010,40(1):58-60

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Geological Reform     

Gabriel Gohau 《Metascience》2009,18(1):53-60

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Assessing Fat Mass of Adolescent Swimmers Using Anthropometric Equations: A DXA Validation Study     

Gabriel Lozano-Berges  Alejandro Gómez-Bruton  Ángel Matute-Llorente  Cristina Julián-Almárcegui  Alba Gómez-Cabello  Alejandro González-Agüero 《Research quarterly for exercise and sport》2017,88(2):230-236

Purpose: The aim of the present study was to determine which of the published anthropometric equations is the most appropriate to estimate body-fat percentage (BF_%) in adolescent swimmers. Method: Eighty-eight swimmers (45 boys, 43 girls) participated in this study. Following the recommendations of the International Society of the Advancement of Kinanthropometry, biceps, triceps, subscapular, iliac-crest, supraspinale, front-thigh, and medial calf skinfold thicknesses were measured. Waist, hip, midthigh, calf, relaxed arm, and arm flexed and tensed girths were also registered. BF_% was measured with dual-energy X-ray absorptiometry (DXA) to obtain the reference value. Existing anthropometric equations were applied, and BF_% results obtained from anthropometric equations were compared to DXA BF_% results with the modified Bland-Altman. Results: The Flavel, Durnin-Rahaman-Siri, and Durnin-Rahaman-Brozek were the only equations that did not demonstrate statistically significant differences when compared with DXA. Conclusion: The present study showed that the best anthropometric equation from existing literature to estimate BF_% in swimmers is that proposed by Durnin-Rahaman (independently of applying the Siri or Brozek equation).  相似文献   

The location of the tibial accelerometer does influence impact acceleration parameters during running     

Angel Gabriel Lucas-Cuevas  Alberto Encarnación-Martínez  Andrés Camacho-García  Salvador Llana-Belloch  Pedro Pérez-Soriano 《Journal of sports sciences》2017,35(17):1734-1738

Tibial accelerations have been associated with a number of running injuries. However, studies attaching the tibial accelerometer on the proximal section are as numerous as those attaching the accelerometer on the distal section. This study aimed to investigate whether accelerometer location influences acceleration parameters commonly reported in running literature. To fulfil this purpose, 30 athletes ran at 2.22, 2.78 and 3.33 m · s^–1 with three accelerometers attached with double-sided tape and tightened to the participants’ tolerance on the forehead, the proximal section of the tibia and the distal section of the tibia. Time-domain (peak acceleration, shock attenuation) and frequency-domain parameters (peak frequency, peak power, signal magnitude and shock attenuation in both the low and high frequency ranges) were calculated for each of the tibial locations. The distal accelerometer registered greater tibial acceleration peak and shock attenuation compared to the proximal accelerometer. With respect to the frequency-domain analysis, the distal accelerometer provided greater values of all the low-frequency parameters, whereas no difference was observed for the high-frequency parameters. These findings suggest that the location of the tibial accelerometer does influence the acceleration signal parameters, and thus, researchers should carefully consider the location they choose to place the accelerometer so that equivalent comparisons across studies can be made.  相似文献   

金发碧眼的对决 第二届国务总理杯世界业余围棋锦标赛     

Jan Ramon  Cristian Gabriel Pop 《棋艺(象棋版)》2008,(1)

看到对局者的姓名,估计大家有些不适应,看棋谱习惯了看中文名字,突然看到两个老外名字,多多少少有点新鲜。这一期介绍了欧洲围棋的发展,下面我们将通过国务总理杯世界围棋锦标赛的一盘对局来具体了解一下欧洲棋手的实力。黑棋比利时的Ramon是那届比赛的一匹黑马,是前四轮仅有的保持全胜的五名棋手之一。而白棋罗马尼亚的Pop则是欧洲非常有名的棋手,他的水平应该代表了目前欧洲的最高水平。  相似文献   

The effectiveness of four readiness tests as predictors of first grade academic achievement     

Gabriel A. Telegdy 《Psychology in the schools》1975,12(1):4-11

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The relationship between socioeconomic status and patterns of WISC scores in children with learning disabilities     

Gabriel A. Telegdy 《Psychology in the schools》1973,10(4):426-430

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