Abstract: Improved microfluidic devices, systems, and methods allow selective transportation of fluids within microfluidic channels of a microfluidic network by applying, controlling, and varying pressures at a plurality of reservoirs. Modeling the microfluidic network as a series of nodes connected together by channel segments and determining the flow resistance characteristics of the channel segments may allow calculation of fluid flows through the channel segments resulting from a given pressure configuration at the reservoirs. To effect a desired flow within a particular channel or series of channels, reservoir pressures may be identified using the network model. Viscometers or other flow sensors may measure flow characteristics within the channels, and the measured flow characteristics can be used to calculate pressures to generate a desired flow. Multi-reservoir pressure modulator and pressure controller systems can optionally be used in conjunction with electrokinetic or other fluid transport mechanisms.

Abstract: Methods for monitoring time dependent reactions that comprise providing a flow channel, typically microscale in dimension, flowing at least two reagents into the flow channel and varying the flow rate of the mixture through the flow channel. By increasing and/or decreasing the flow rate of the reagent mixture from the point of mixing to the point of detection, one alters the amount of reaction time, allowing monitoring reaction kinetics over time.

Abstract: Analytical systems and methods that use a modular interface structure for providing an interface between a sample substrate and an analytical unit, where the analytical unit typically has a particular interface arrangement for implementing various analytical and control functions. Using a number of variants for each module of the modular interface structure advantageously provides cost effective and efficient ways to perform numerous tests using a particular substrate or class of substrates with a particular analytical and control systems interface arrangement. Improved optical illumination and detection system for simultaneously analyzing reactions or conditions in multiple parallel microchannels are also provided.

Abstract: Microfluidic devices for performing integrated reaction and separation operations. The devices include a planar substrate having a first surface with an integrated channel network disposed therein. The reaction region in the integrated microscale channel network has a mixture of at least first and second reactants located therein, wherein the mixture interacts to produce one or more products. The reaction region is configured to maintain contact between the first and second reactants contained within it. The device also includes a separation region in the integrated channel network, where the separation region is configured to separate the first reactant from the product, when the first reactant and product are flowing through the separation region. The conductivity of a fluid in the reaction region is higher than the conductivity of a fluid in the separation region.

Abstract: Methods, apparatus and systems are provided for introducing large numbers of different materials into a microfluidic analytical device rapidly, efficiently and reproducibly. In particular, improved integrated pipettor chip configurations, e.g. sippers or electropipettors, are described which are capable of sampling extremely small amounts of material for which analysis is desired, transporting material into a microfluidic analytical channel network, and performing the desired analysis on the material.

Abstract: Throughput rates for microfluidic serial analysis systems are optimized by maximizing the proximity and speed with which multiple different samples may be serially introduced into a microfluidic channel network. Devices are included that include optimized parameters based upon desired throughput rates for a given set of reagents, reaction times and the like.

Abstract: A polymer composition is provided for use as a liquid lens element in a compound lens designed to reduce chromatic aberration. The polymer composition (i) has an abnormal optical dispersion and (ii) is more easily fabricated into the compound lens than a conventional optical liquid. The composition contains an abnormal optical liquid characterized by an abnormal optical dispersion and a polymer component. The polymer is soluble in the optical liquid and is present in an amount effective to impart a viscosity that is at least an order of magnitude greater than that of the liquid alone at a selected temperature.

Abstract: Soil, contaminated with radioactive material such as uranium, is treated to remove the radioactive contaminant. The soil is first pre-processed to remove and clean oversized particles for release back to the environment as recovered soil. Pre-processing also includes removal of metallic uranium from the soil by gravimetric separation for off-site disposal. An aqueous slurry is formed from the pre-processed feed which is fed to a mechanical separation device. Particles greater than 10 mesh are crushed to provide a uniform feed slurry. The slurry is processed in an aqueous leaching solution of sulfuric acid, hydrogen peroxide and iron to remove uranium. Particulate matter is removed from the acidic slurry; the remaining fine particulate matter is then submitted to a second-stage leaching to remove residual uranium. Uranium is recovered from the combined leaching solutions by either a two-stage precipitation process or by passage over an ion-exchange material.