In this paper, centrifuge-based microfluidic platforms are reviewed and compared with other popular microfluidic propulsion methods. The underlying physical principles of centrifugal pumping in microfluidic systems are presented and the various centrifuge fluidic functions, such as valving, decanting, calibration, mixing, metering, heating, sample splitting, and separation, are introduced. Thos...

In wetland-adapted plants, such as rice, it is typically root apexes, sites of rapid entry for water/nutrients, where radial oxygen losses (ROLs) are highest. Nutrient/toxic metal uptake therefore largely occurs through oxidized zones and pH microgradients. However, the processes controlling the acquisition of trace elements in rice have been difficult to explore experimentally because of a lac...

Measurement of the blood-oxygen-level dependent (BOLD) response with fMRI has revolutionized cognitive neuroscience and is increasingly important in clinical care. The BOLD response reflects changes in deoxy-hemoglobin concentration, blood volume, and blood flow. These hemodynamic changes ultimately result from neuronal firing and synaptic activity, but the linkage between these domains is comp...

The effect of task-related extracerebral circulatory changes on diffuse optical tomography (DOT) of brain activation was evaluated using experimental data from 14 healthy human subjects and computer simulations. Total hemoglobin responses to weekday-recitation, verbal-fluency, and hand-motor tasks were measured with a high-density optode grid placed on the forehead. The tasks caused varying lev...

Continuous physiological monitoring of electrolytes and small molecules such as glucose, creatinine, and urea is currently unavailable but achieving such a capability would be a major milestone for personalized medicine. Optode-based nanosensors are an appealing analytical platform for designing in vivo monitoring systems. In addition to the necessary analytical performance, such nanosensors mu...

Oxygen transfer in the capillary fringe (CF) is of primary importance for a wide variety of biogeochemical processes occurring in shallow groundwater systems. In case of a fluctuating groundwater table two distinct mechanisms of oxygen transfer within the capillary zone can be identified: vertical predominantly diffusive mass flux of oxygen, and mass transfer between entrapped gas and groundwat...

Knowledge about environmental impacts associated with the application of anaerobic digestion residue to agricultural land is of interest owing to the rapid proliferation of biogas plants worldwide. However, virtually no information exists concerning how soil-emitted NO is affected by the feedstock hydraulic retention time (HRT) in the biogas digester. Here, the O planar optode technique was use...

This study proposes the implementation of an algorithm allowing one to derive absolute blood root-mean-square (RMS) velocity values from laser Doppler perfusion meter (LDP) data. The algorithm is based on the quasi-elastic light scattering theory and holds for multiple scattering. While standard LDP measurements are normally applicable to a small region of interest (approximately 1 mm2), the pr...

A methodology for oxygen profile measurements in the unsaturated zone is developed based on direct push drilling using sampling liners equipped with homemade silicone septa. The oxygen measurement is carried out by puncturing the septum with a commercial retractable optode needle fitted with a fluorescent tip. Metrological characteristics and method validation were carried out under laboratory ...