106 research outputs found
Microfluidic detection and analysis by integration of thermocapillary actuation with a thin-film optical waveguide
We demonstrate a nonintrusive optical method for microfluidic detection and analysis based on evanescent wave sensing. The device consists of a planar thin-film waveguide integrated with a microfluidic chip for directed surface flow. Microliter droplets are electronically transported and positioned over the waveguide surface by thermocapillary actuation. The attenuated intensity of propagating modes is used to detect droplet location, to monitor dye concentration in aqueous solutions, and to measure reaction rates with increasing surface temperature for a chromogenic biochemical assay. This study illustrates a few of the capabilities possible by direct integration of optical sensing with surface-directed fluidic devices
Microfluidic actuation by modulation of surface stresses
We demonstrate the active manipulation of nanoliter liquid samples on the surface of a glass or silicon substrate by combining chemical surface patterning with electronically addressable microheater arrays. Hydrophilic lanes designate the possible routes for liquid migration while activation of specific heater elements determine the trajectories. The induced temperature fields spatially modulate the liquid surface tension thereby providing electronic control over the direction, timing, and flow rate of continuous streams or discrete drops. Temperature maps can be programed to move, split, trap, and mix ultrasmall volumes without mechanically moving parts and with low operating voltages of 2â3 V. This method of fluidic actuation allows direct accessibility to liquid samples for handling and diagnostic purposes and provides an attractive platform for palm-sized and battery-powered analysis and synthesis
Population Studies of Eurasian Watermilfoil ( Myriophyllum spicatum ) and Zebra Mussels (Dreissena polymorpha) in Conesus Lake, N.Y. (Summer 2000)
The primary goal of our research during the summer 2000 was to examine the distribution and density Eurasian watermilfoil beds and of populations of zebra mussels in Conesus Lake. The results of this study improve our knowledge of these populations and contribute to the scientific foundation required for consideration of possible management strategies. A secondary goal of this project was to extend our long term database on macrophyte growth at two sites first studied by Herman Forest and his colleagues in 1967
Thermocapillary Actuation of Liquids Using Patterned Microheater Arrays
ABSTRACT We demonstrate a microfluidic actuation technique capable of directing nanoliter liquid samples on the surface of a glass substrate through the use of both electronically addressable heater arrays and chemical patterning. Pathways for liquid movement are delineated by the arrangement of microheaters, which also provide the thermocapillary actuating force. The drops are confined to these pathways by a selectively deposited fluorinated monolayer, which defines the channel edges. Operating voltages in the range of 2-3 V is used to move, split, and trap liquids. This fluid transportation technique enables direct access to liquid samples for handling and diagnostic purposes and offers a low power alternative to existing microfluidic systems
Planar digital nanoliter dispensing system based on thermocapillary actuation
We provide guidelines for the design and operation of a planar digital nanodispensing system based on
thermocapillary actuation. Thin metallic microheaters embedded within a chemically patterned glass
substrate are electronically activated to generate and control 2D surface temperature distributions
which either arrest or trigger liquid flow and droplet formation on demand. This flow control is
a consequence of the variation of a liquidâs surface tension with temperature, which is used to draw
liquid toward cooler regions of the supporting substrate. A liquid sample consisting of several
microliters is placed on a flat rectangular supply cell defined by chemical patterning. Thermocapillary
switches are then activated to extract a slender fluid filament from the cell and to divide the filament into
an array of droplets whose position and volume are digitally controlled. Experimental results for the
power required to extract a filament and to divide it into two or more droplets as a function of
geometric and operating parameters are in excellent agreement with hydrodynamic simulations. The
capability to dispense ultralow volumes onto a 2D substrate extends the functionality of microfluidic
devices based on thermocapillary actuation previously shown effective in routing and mixing nanoliter
liquid samples on glass or silicon substrates
Recommendations for Implementing Lung Cancer Screening with Low-Dose Computed Tomography in Europe.
Lung cancer screening (LCS) with low-dose computed tomography (LDCT) was demonstrated in the National Lung Screening Trial (NLST) to reduce mortality from the disease. European mortality data has recently become available from the Nelson randomised controlled trial, which confirmed lung cancer mortality reductions by 26% in men and 39-61% in women. Recent studies in Europe and the USA also showed positive results in screening workers exposed to asbestos. All European experts attending the "Initiative for European Lung Screening (IELS)"-a large international group of physicians and other experts concerned with lung cancer-agreed that LDCT-LCS should be implemented in Europe. However, the economic impact of LDCT-LCS and guidelines for its effective and safe implementation still need to be formulated. To this purpose, the IELS was asked to prepare recommendations to implement LCS and examine outstanding issues. A subgroup carried out a comprehensive literature review on LDCT-LCS and presented findings at a meeting held in Milan in November 2018. The present recommendations reflect that consensus was reached
Recommendations for implementing lung cancer screening with low-dose computed tomography in Europe
Lung cancer screening (LCS) with low-dose computed tomography (LDCT) was
demonstrated in the National Lung Screening Trial (NLST) to reduce mortality from the disease.
European mortality data has recently become available from the Nelson randomised controlled
trial, which confirmed lung cancer mortality reductions by 26% in men and 39â61% in women.
Recent studies in Europe and the USA also showed positive results in screening workers exposed to
asbestos. All European experts attending the âInitiative for European Lung Screening (IELS)ââa
large international group of physicians and other experts concerned with lung cancerâagreed that
LDCT-LCS should be implemented in Europe. However, the economic impact of LDCT-LCS and
guidelines for its effective and safe implementation still need to be formulated. To this purpose, the
IELS was asked to prepare recommendations to implement LCS and examine outstanding issues.
A subgroup carried out a comprehensive literature review on LDCT-LCS and presented findings at
a meeting held in Milan in November 2018. The present recommendations reflect that consensus
was reached
Exploring Cosmic Origins with CORE: Cosmological Parameters
We forecast the main cosmological parameter constraints achievable with theCORE space mission which is dedicated to mapping the polarisation of the CosmicMicrowave Background (CMB). CORE was recently submitted in response to ESA'sfifth call for medium-sized mission proposals (M5). Here we report the resultsfrom our pre-submission study of the impact of various instrumental options, inparticular the telescope size and sensitivity level, and review the great,transformative potential of the mission as proposed. Specifically, we assessthe impact on a broad range of fundamental parameters of our Universe as afunction of the expected CMB characteristics, with other papers in the seriesfocusing on controlling astrophysical and instrumental residual systematics. Inthis paper, we assume that only a few central CORE frequency channels areusable for our purpose, all others being devoted to the cleaning ofastrophysical contaminants. On the theoretical side, we assume LCDM as ourgeneral framework and quantify the improvement provided by CORE over thecurrent constraints from the Planck 2015 release. We also study the jointsensitivity of CORE and of future Baryon Acoustic Oscillation and Large ScaleStructure experiments like DESI and Euclid. Specific constraints on the physicsof inflation are presented in another paper of the series. In addition to thesix parameters of the base LCDM, which describe the matter content of aspatially flat universe with adiabatic and scalar primordial fluctuations frominflation, we derive the precision achievable on parameters like thosedescribing curvature, neutrino physics, extra light relics, primordial heliumabundance, dark matter annihilation, recombination physics, variation offundamental constants, dark energy, modified gravity, reionization and cosmicbirefringence. (ABRIDGED
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