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Details of a fast and sustainable bottom-up process to grow large area high quality graphene films without the aid of any catalyst are reported in this paper. We used Melaleuca alternifolia, a volatile natural extract from tea tree plant as the precursor. The as-fabricated graphene films yielded a stable contact angle of 135°, indicating their potential application in very high hydrophobic coatings. The electronic devices formed by sandwiching pentacene between graphene and aluminum films demonstrated memristive behavior, and hence, these graphene films could find use in nonvolatile memory devices also.

Abstract. Optical topography ͑OT͒ based on near-infrared spectroscopy is a noninvasive technique for mapping the relative concentration changes in oxygenated and deoxygenated hemoglobin ͑oxy-and deoxy-Hb, respectively͒ in the human cerebral cortex. In our previous study, we developed a small and light wearable optical topography ͑WOT͒ system that covers the entire forehead for monitoring prefrontal activation. In the present study, we examine whether the WOT system is applicable to OT measurement while walking, which has been difficult with conventional OT systems. We conduct OT measurements while subjects perform an attention-demanding ͑AD͒ task of balancing a ping-pong ball on a small card while walking. The measured time course and power spectra of the relative concentration changes in oxy-and deoxy-Hb show that the step-related changes in the oxy-and deoxy-Hb signals are negligible compared to the taskrelated changes. Statistical assessment of the task-related changes in the oxy-Hb signals show that the dorsolateral prefrontal cortex and rostral prefrontal area are significantly activated during the AD task. These results suggest that our functional imaging technique with the WOT system is applicable to OT measurement while walking, and will be a powerful tool for evaluating brain activation in a natural environment.

By using the electric field induced optical second-harmonic generation (EFISHG) measurements, we probed the transient electric field in a double-layer indium zinc oxide (IZO)/N, N′-di-[(1-naphthyl)-N,N′-diphenyl]-(1,1′-biphenyl)-4, 4′-diamine(α-NPD)/tris(8-hydroxy-quinolinato)aluminum(III) (Alq3)/Al electroluminescent (EL) diode. Results evidently showed that EL was initiated by the injected hole transport across α-NPD layer, and holes accumulated at the α-NPD/Alq3 interface while EL was enhanced. Analysis based on the Maxwell–Wagner effect model well accounted for the hole accumulation. EFISHG measurement is useful as a tool for probing carrier behavior in organic EL devices.

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Cysteine modified NH 2 -end peptide nucleic acid (PNA) (24-mer) probe and 5¢-thiol end labeled deoxyribonucleic acid (DNA) probes specific to Mycobacterium tuberculosis have been immobilized onto BK-7 gold coated glass plates for the detection of complementary, one-base mismatch, non-complementary targets and complementary target sequence in genomic DNA of Mycobacterium tuberculosis using a surface plasmon resonance (SPR) technique. The DNA/Au and PNA/Au bio-electrodes have been characterized using contact angle, atomic force microscopy (AFM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetric (CV) techniques, respectively. It is revealed that there is a 252 millidegrees SPR angle change in the case of PNA immobilization and 205 millidegrees for DNA immobilization, indicating increased amount of immobilized PNA molecules. Hybridization studies reveal that there is no binding of the non-complementary target to DNA/Au and PNA/Au electrode. Compared to the DNA/Au bioelectrode, PNA/Au electrode has been found to be more efficient for detection of one-base mismatch sequence. The PNA/Au bioelectrode shows better detection limit (1.0 ng ml -1 ) over the DNA-Au bioelectrode (3.0 ng ml -1 ). The values of the association (k a ) and dissociation rate constant (k d ) for the complementary sequence in case of the PNA/Au bioelectrode have been estimated as 8.5 ¥ 10 4 m -1 s -1 and 3.6 ¥ 10 -3 s -1 , respectively.