A disposable,reagentless, third-generation glucose biosensor based on overoxidized poly(pyrrole)/tetrathiafulvalene-tetracyanoquinodimethane composite

A disposable glucose biosensor based on glucose oxidase immobilized on tetrathiafulvalene-tetracyanoquinodimethane (ITF-TCNQ) conducting organic salt synthesized in situ onto an overoxidized poly(pyrrole) (PPy(ox).) film is described. The TIF-TCNQ crystals grow through the nonconducting polypyrrole film (ensuring electrical connection to the underlying Pt electrode) and emerge from the film forming a treelike structure. The PPy(ox) film prevents the interfering substances from reaching the electrode surface. The sensor behavior can be modeled by assuming a direct reoxidation of the enzyme at the surface of the TTF-TCNQ crystals. A heterogeneous rate constant around 10(-6) - 10(-7) cm s(-1) has been estimated. The biosensor is nearly oxygen- and interference-free and when integrated in a flow injection system displays a remarkable sensitivity (70 nA/mM) and stability.     

Silicon Bipolar LNAs in the X and Ku Bands

Two fully integrated silicon bipolar LNAs at 8 and 12 GHz are presented. Both circuits provide simultaneous noise and input impedance matching. Resonant loads, designed for 50-Ω output matching, are also included. Moreover, the noise and input impedance self-matching trend of the cascode topology in the X and Ku bands was also explored and the design of integrated spiral inductors was discussed. From an on-wafer test, the 8 and the 12-GHz LNAs exhibit a power gain of 11.5 and 8 dB and a noise figure of 2.6 and 4.7 dB, respectively. This performance was achieved with bias currents as low as 4 mA for each circuit. The two LNAs were fabricated in a 46-GHz-f _T pure bipolar technology.     

Differences in virtual and physical head orientation predict sickness during active head-mounted display-based virtual reality

Virtual Reality - During head-mounted display (HMD)-based virtual reality (VR), head movements and motion-to-photon-based display lag generate differences in our virtual and physical head pose...     

Effects of display lag on vection and presence in the Oculus Rift HMD

Virtual Reality - Head-mounted display (HMD)-based virtual reality (VR) is ideally suited for presence and generating compelling visual experiences of self-motion, but users can suffer from side...     

Heterogeneous photocatalytic systems: Influence of some operational variables on actual photons absorbed by aqueous dispersions of TiO2

The photooxidation of phenol in aqueous solution in the presence of polycrystalline TiO₂ powder was used as "test" reaction in order to investigate the influence of incident light intensity and of some physical and chemical parameters on the actual absorbed photon flows and on the reactivity. The physical parameters investigated were the surface area and the size of particles while the chemical parameters investigated were the initial pH of the dispersion and the presence in the reacting medium of additives affecting the photoreactivity such as Cl⁻ and H₂O₂.