Capacitive Pressure Sensor with Wide-Range, Bendable, and High Sensitivity Based on the Bionic Komochi Konbu Structure and Cu/Ni Nanofiber Network.

High-performance flexible pressure sensors have an essential application in many fields such as human detection and human-computer interaction. Herein, on the basis of the dielectric layer of a bionic komochi konbu structure, we propose a low-cost and novel capacitive sensor that achieves high sensitivity and stability over a broad range of tactile pressures. Further, the flexible and durable electrode layer of the transparent junctionless copper/nickel-nanonetwork was prepared based on electrospinning and electroless deposition techniques, which ensured high bending stability and high cycle stability of our sensor. More importantly, because of the sizeable protruding structure and internal micropores in the elastomer structure we designed, the inward curling of the protruding structure and the effectual closing of the micropores increase the effective dielectric constant under the action of the compressive force, improving the sensitivity of the sensor. Measured response and relaxation time (162 ms) are 250 times faster than those of a conventional flat polydimethylsiloxane capacitive sensor. In addition, the fabricated capacitive pressure sensor demonstrates the ability to be used on wearable applications, not only to quickly recognize the tapping and bending of a finger but also to show that the pressure of the finger can be sensed when the finger grabs the object. The sensors we have developed have shown great promise in practical applications, such as human rehabilitation and exercise monitoring, as well as human-computer interaction control.

Millisecond analysis of double stranded DNA with fluorescent intercalator by micro-thermocontrol-device.

Study of interaction between DNA and intercalator at molecular level is important to understand the mechanisms of DNA replication and repair. A micro-fabricated local heating thermodevice was adapted to perform denaturation experiments of DNA with fluorescent intercalator on millisecond time scale. Response time of complete unzipping of double stranded DNA, 16 microm in length, was measured to be around 5 min by commercial thermocycler. Response time of quenching of double stranded DNA with fluorescent intercalator SYBR Green was measured to be 10 ms. Thus, quenching properties owing to strand unzipping and denaturation at base pair level were distinguished. This method has provided easy access to measure this parameter and may be a powerful methodology in analyzing biomolecules on millisecond time scale.

Synthesis, short-range structure, and electrochemical properties of new phases in the Li-Mn-N-O system.

A crystal-chemical exploration of part of the Li-Mn-N-O system was carried out. Several samples were synthesized using Li(3)N, Mn(x)N and Li(2)O and characterized with chemical analysis, XRD, XAS, and NMR. An increase in the starting proportion of Li(2)O increases the amounts of lithium and oxygen in the compounds, but, according to the XANES Mn K-edge spectra, all the oxynitrides still contain Mn(5+) ions preferentially coordinated by N(3-), forming [MnN(4)] tetrahedra. The analysis of the position of these samples in the compositional Li(3)N-Li(2)O-MnN(x) ternary phase diagram and the plot of their cell parameters against the oxygen molar fraction indicates that all the oxynitrides belong to the same tie-line, which also includes Li(2)O but not Li(7)MnN(4). Although the XRD patterns suggest that these samples crystallize in a disordered antifluorite-type structure, the analysis of the (6)Li NMR data indicates that short-range ordering does exist. The performance as electrode materials in lithium batteries of the synthesized samples was also evaluated. Li(7.9)MnN(3.2)O(1.6) was shown to be the most attractive candidate because of its higher capacity values and improved retention upon cycling with respect to the other members of the series.

Millisecond denaturation dynamics of fluorescent proteins revealed by femtoliter container on micro-thermodevice.

Real-time observation of biomolecular behavior focusing on high speed temperature response is an essential endeavor for further biological study at the molecular level. This is because most of the important biological functions at the molecular level happen at the sub-second time scale. We used our own on-chip microheaters and microcontainers to observe the denaturation dynamics of fluorescent proteins at the millisecond time scale. The microheater controls the temperature in 1 ms under the microscope. Fluorescent proteins were contained in 28 fL PDMS microcontainers to prevent them from diffusing into the solution. The proteins were denatured by high temperatures and observed by a high speed CCD camera with 5 ms per frame. Hence, denaturation speeds of red fluorescent proteins (rDsRed and rHcRed) were measured to be 5-10 ms. Green fluorescent proteins (rAcGFP and rGFPuv) denatured with bi-exponential decay. rAcGFP denatured with time constants of 5 ms and 75 ms while rGFPuv denatured with 10 ms and 130 ms. This may be the reverse process of a two step renaturation of GFP observed in a previous report. This micro-thermodevice is applicable to other biomaterials such as nucleic acids or other proteins. It does not require any chemical treatment nor mutation to the biomaterial itself. Therefore, the methodology using this general purpose device gives access to biomolecular studies in short time scales and acts as a powerful tool in molecular biology.

On-chip thermal calibration with 8 CB liquid crystal of micro-thermal device.

A temperature sensor integrated on a micro-device for biological experiments requires affordable, rapid and easy thermal calibration. However, such calibration cannot usually be done directly under the microscope, a fact that impedes biological experiments. We present in this paper an inexpensive and rapid method to achieve thermal calibration directly under the microscope. It is based on the use of a thermotropic liquid crystal: the 4-n-octyl-4-cyanobiphenyl (8 CB) exhibiting an isothermal phase change at 313 K that can be monitored optically. We demonstrate the advantages of this method by calibrating the temperature sensor integrated onto a micro-device.