To solve the problems of electromagnetic interference and heat dissipation generated in miniaturized and highly integrated modern electronics, we pioneered the use of TiO2 /Fe/C nanocomposites as advanced heat conduction-microwave absorption integrated materials (HCMWAIMs). The TiO 2 /Fe/C nanocomposites were produced by a simple one-step pyrolyzation route using pentacarbonyle (Fe(CO) 5 ) as C and Fe sources and nanoscale titanium dioxide (P25) as a precursor. The phase structure, Ti/Fe atomic ratios, and defects of the TiO 2 /Fe/C nanocomposites were expediently adjusted by controlling the Fe(CO) 5 volume. In the case where the Fe(CO) 5 volume was increased, the electric conductivity increased linearly with the increasing Fe/Ti atomic ratio, while the heat conductivity changed in a reversed U shape. Results showed that the TiO 2 /Fe/C nanocomposites prepared by the combination of TiO2 with Fe and C possess higher heat conductivity (1.870 W/(m×K)), excellent electric insulation (0.593 S/m), larger ABW/d values 5.6 GHz/mm), higher absorption (−42.59 dB), and thinner films (1.2~2.1 mm) than other previously reported materials. The excellent comprehensive capabilities result from the combined action of interfaces and defects. The as-obtained TiO 2 /Fe/C nanocomposites are expected to be efficient HCMWAIMs used in electronic devices.
A stem-loop clutch probe (SLCP)-based strategy has been explored to guide sequence-specific double stranded DNA (dsDNA) analysis with enhanced single-base mismatch selectivity. This assay method can also modulate the dynamic range by employing natural processes relying on distal-site mutation inhibition and allosteric activation.
There is an urgent need for reliable biosensors to detect nucleic acid of interest in clinical samples. We propose that the accuracy of the present nucleic acid-sensing method can be advanced by avoiding false-positive identifications derived from nonspecific interactions (e.g., nonspecific binding, probe degradation). The challenge is to exploit biosensors that can distinguish false-positive from true-positive samples in nucleic acid screening. In the present study, by learning from the enzymatic cycle in nature, we raise an allostery tool displaying invertible positive/negative cooperativity for reversible or cyclic activity control of the biosensing probe. We demonstrate that the silencing and regeneration of a positive (or negative) allosteric effector can be carried out through toehold displacement or an enzymatic reaction. We, thus, have developed several dynamic biosensors that can repeatedly measure a single nucleic acid sample. The ability to distinguish a false-positive from a true-positive signal is ascribed to the nonspecific interaction presenting equivalent signal variations, while the specific target binding exhibits diverse signal variations according to repeated measurements. Given its precise identification, such consequent dynamic biosensors offer exciting opportunities in physiological and pathological diagnosis.
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