RESUMO
Sources of individual differences in scientific problem solving were investigated. Participants representing a wide range of experience in geology completed tests of visuospatial ability and geological knowledge, and performed a geological bedrock mapping task, in which they attempted to infer the geological structure of an area in the Tobacco Root Mountains of Montana. A Visuospatial Ability × Geological Knowledge interaction was found, such that visuospatial ability positively predicted mapping performance at low, but not high, levels of geological knowledge. This finding suggests that high levels of domain knowledge may sometimes enable circumvention of performance limitations associated with cognitive abilities.
Assuntos
Cognição , Aprendizagem , Resolução de Problemas , Percepção Espacial , Adulto , Feminino , Geologia , Humanos , Individualidade , Conhecimento , Masculino , Pessoa de Meia-Idade , Testes NeuropsicológicosRESUMO
An image-patterned molecular delivery system for mammalian cells is demonstrated by pulsed laser irradiation of gold particles immobilized on a substrate below a cell monolayer. Patterned cavitation bubble nucleation was captured using a time-resolved imaging system and molecular delivery verified by observing the uptake of a membrane-impermeable fluorescent dye, calcein. Delivery efficiency as high as 90% was observed and multiplexed, patterned dye delivery was demonstrated.
Assuntos
Membrana Celular/química , Sistemas de Liberação de Medicamentos/métodos , Fluoresceínas/química , Ouro/química , Ouro/efeitos da radiação , Rim/química , Pinças Ópticas , Membrana Celular/efeitos da radiação , Difusão/efeitos da radiação , Fluoresceínas/efeitos da radiação , Células HeLa , Humanos , Rim/efeitos da radiação , LuzRESUMO
We report on a light-actuated, droplet based microfluidic platform enabling two-dimensional (2D) droplet manipulation on an open chamber with a single-side, featureless photoconductive surface. The droplet actuation mechanism is based on recently demonstrated floating electrode optoelectronic tweezers (FEOET), which enable light-induced dielectrophoretic forces to manipulate aqueous droplets immersed in electrically nonconductive oil, with a light intensity as low as 400 microW/cm2. In this paper, we study the shape effect of optical patterns for 2D droplet actuation, and demonstrate light-actuated droplet manipulation functions including 2D droplet transport, merging, mixing, and multidroplet processing, for up to 16 droplets in parallel. Such an open chamber platform also permits easy interfacing and integration with other microfluidic structures, such as wells and close-channel based droplet devices to increase its versatility for biochemical analyses.
Assuntos
Eletroforese em Microchip/instrumentação , Eletroforese em Microchip/métodos , Luz , Microfluídica , Microfluídica/instrumentação , Microfluídica/métodosRESUMO
We report an optical actuation mechanism, floating electrode optoelectronic tweezers (FEOET). FEOET enables light-driven transport of aqueous droplets immersed in electrically insulating oil on a featureless photoconductive glass layer with direct optical images. We demonstrate that a 681 mum de-ionized water droplet immersed in corn oil medium is actuated by a 3.21 muW laser beam with an average intensity as low as 4.08 muWmm(2) at a maximum speed of 85.1 mums on a FEOET device. FEOET provides a promising platform for massively parallel droplet manipulation with optical images on low cost, silicon-coated glass. The FEOET device structure, fabrication, working principle, numerical simulations, and operational results are presented in this letter.
