DNA multi-bit non-volatile memory and bit-shifting operations using addressable electrode arrays and electric field-induced hybridization.

DNA has been employed to either store digital information or to perform parallel molecular computing. Relatively unexplored is the ability to combine DNA-based memory and logical operations in a single platform. Here, we show a DNA tri-level cell non-volatile memory system capable of parallel random-access writing of memory and bit shifting operations. A microchip with an array of individually addressable electrodes was employed to enable random access of the memory cells using electric fields. Three segments on a DNA template molecule were used to encode three data bits. Rapid writing of data bits was enabled by electric field-induced hybridization of fluorescently labeled complementary probes and the data bits were read by fluorescence imaging. We demonstrated the rapid parallel writing and reading of 8 (23) combinations of 3-bit memory data and bit shifting operations by electric field-induced strand displacement. Our system may find potential applications in DNA-based memory and computations

Influence of MWCNTs on β

The surface of multiwalled carbon nanotubes (MWCNTs) was chemically modified using 1-pyrenebutyric acid (PBA) to improve its compatibility with polyvinylidene fluoride (PVDF). The carboxylic acid groups of the MWCNTs-PBA (PCNTs) provide a β-phase nucleation site to the fluorine of PVDF along their surface. The content of the β-phase crystalline structure of PVDF was found to be the highest at a concentration of 1.0 wt.% of PCNTs, and these PVDF-PCNTs composites were utilized as active layers in triboelectric devices. The maximum output voltage achieved was 16 volts at a concentration of 1.0 wt.% of PCNTs in the PVDF composites

Controllable synthesis of molybdenum tungsten disulfide alloy for vertically composition-controlled multilayer

The effective synthesis of two-dimensional transition metal dichalcogenides alloy is essential for successful application in electronic and optical devices based on a tunable band gap. Here we show a synthesis process for Mo<inf>1-x</inf>W<inf>x</inf>S<inf>2</inf> alloy using sulfurization of super-cycle atomic layer deposition Mo<inf>1-x</inf>W<inf>x</inf>O<inf>y</inf>. Various spectroscopic and microscopic results indicate that the synthesized Mo<inf>1-x</inf>W<inf>x</inf>S<inf>2</inf> alloys have complete mixing of Mo and Watoms and tunable band gap by systematically controlled composition and layer number. Based on this, we synthesize a vertically composition-controlled (VCC) Mo<inf>1-x</inf>W<inf>x</inf>S<inf>2</inf> multilayer using five continuous super-cycles with different cycle ratios for each super-cycle. Angle-resolved X-ray photoemission spectroscopy, Raman and ultraviolet-visible spectrophotometer results reveal that a VCC Mo<inf>1-x</inf>W<inf>x</inf>S<inf>2</inf> multilayer has different vertical composition and broadband light absorption with strong interlayer coupling within a VCC Mo<inf>1-x</inf>W<inf>x</inf>S<inf>2</inf> multilayer. Further, we demonstrate that a VCC Mo<inf>1-x</inf>W<inf>x</inf>S<inf>2</inf> multilayer photodetector generates three to four times greater photocurrent than MoS<inf>2</inf>-and WS<inf>2</inf>-based devices, owing to the broadband light absorption. © 2015 Macmillan Publishers Limitedopen1

Nanoparticles Patterning by Directed Electric Field Assembly and Photolithography

Recently, the integration of a wide range of nanocomponents has been investigated for building patterned or layered structures on the macroscopic and mesoscopic scale. In order to break through the issues of current devices and develop diverse and reliable applications from nanobiomaterials to nanoelectronics, it is necessary to fabricate nano-devices and systems using nanocomponents. However, traditional fabrication methods have required the modification of these nanomaterials, and need new approaches for the advancement of development for diverse and reliable applications. In this dissertation, two novel methods are demonstrated for pragmatic nano devices and systems : Controlling extrinsic nanoparticle alignment by electrical field deposition, and intrinsic DNA binding through photolithography. First, the use of nanoparticles' electrophoretic deposition (EPD) onto porous biodegradable polymer allows the production of transparent flexible carbon nanotube network films with mechanical strength. Most importantly, after solvent treatment, the opaque substrate changed to transparent with conductivity. Thus, we produced flexible transparent films. Another unique aspect of this process is that after solvent treatment, the substrate can be implanted onto newspapers or cloth. Second, we demonstrate a DNA double write process that represents, which allows DNA to be used as a unique material for UV patterning, with subsequent selfassembly via the hybridization of complementary DNA sequences. This novel method allows true synergy for combining top-down photolithography with bottom-up selfassembly. In addition, we have been able to demonstrate both first- and second-level patterning, including target sequence detection and streptavidin / biotin binding with the DNA double write proces

Processing DNA Storage through Programmable Assembly in a Droplet‐Based Fluidics System

Abstract DNA can be used to store digital data, and synthetic short‐sequence DNA pools are developed to store high quantities of digital data. However, synthetic DNA data cannot be actively processed in DNA pools. An active DNA data editing process is developed using splint ligation in a droplet‐controlled fluidics (DCF) system. DNA fragments of discrete sizes (100–500 bps) are synthesized for droplet assembly, and programmed sequence information exchange occurred. The encoded DNA sequences are processed in series and parallel to synthesize the determined DNA pools, enabling random access using polymerase chain reaction amplification. The sequencing results of the assembled DNA data pools can be orderly aligned for decoding and have high fidelity through address primer scanning. Furthermore, eight 90 bps DNA pools with pixel information (png: 0.27–0.28 kB), encoded by codons, are synthesized to create eight 270 bps DNA pools with an animation movie chip file (mp4: 12 kB) in the DCF system

Origin of the Mixing Ratio Dependence of Power Conversion Efficiency in Bulk Heterojunction Organic Solar Cells with Low Donor Concentration

We studied the origin of the improvement in device performance of thermally evaporated bulk heterojunction organic photovoltaic devices (OPVs) with low donor concentration. Samples with three different donor-acceptor mixing ratios, 0:10 (C70-only), 1:9 (low-doped) and 3:7 (high-doped), were fabricated with 1,1-bis-(4-bis(4-methyl-phenyl)-amino-phenyl)-cyclohexane (TAPC):C70. The power conversion efficiencies (PCEs) of these samples were 1.14%, 2.74% and 0.69%, respectively. To determine why the low-doped device showed a high PCE, we measured various properties of the devices in terms of the effective energy band gap, activation energy, charge carrier mobility and recombination loss. We found that the activation energy for charge carrier transport was increased as we increased the TAPC concentration in the blends whereas the hole and electron mobilities became more balanced as the TAPC concentration was increased. Furthermore, the recombination loss parameter alpha (from the light intensity dependence) remained alpha to approximately 0.9 in the low-doped device, but it decreased to alpha to approximately 0.77 in the high-doped device, indicating a large recombination loss as a result of space charge. Therefore, the improved PCE of low-doped OPVs can be attributed to the balance between carrier mobilities with no increase in recombination loss.This work was supported by the Human Resources Development Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No. 20124010203170).OAIID:oai:osos.snu.ac.kr:snu2013-01/102/0000029430/6SEQ:6PERF_CD:SNU2013-01EVAL_ITEM_CD:102USER_ID:0000029430ADJUST_YN:NEMP_ID:A076109DEPT_CD:430CITE_RATE:1.149FILENAME:journal of nanoscience and nanotechnology 13, 7982 (dec, 2013).pdfDEPT_NM:전기·정보공학부EMAIL:[email protected]_YN:YCONFIRM:

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Background Spinal anesthesia and autonomic neuropathy (caused by diabetes) prolong the QTc interval. Changes in the duration of the QTc interval following subarachnoid blockade in patients with diabetes have not been evaluated. We hypothesized that after subarachnoid blockade, QTc interval prolongation would be greater in patients with diabetes than in those without. Accordingly, we compared the QTc interval, T wave peak-to-end interval (Tp-e interval), blood pressure, heart rate, and heart rate variability before and after spinal anesthesia in patients with and without diabetes. Methods This prospective observational study (Clinical Research Information Service identifier: KCT0004897) was conducted in a tertiary university hospital and included 24 patients with diabetes mellitus (DM group) and 24 patients without it (control group) who were scheduled for spinal anesthesia. The QTc interval, Tp-e interval, heart rate variability, blood pressure, and heart rate were measured before (T1) and 1 (T2), 5 (T3), and 10 min (T4) following subarachnoid blockade. Results Ten minutes following subarachnoid blockade, the QTc intervals of patients in the DM group were significantly longer than the baseline values, whereas the change in the QTc interval in the control group was not significant (p < 0.0001 vs. p = 0.06). Conclusion Spinal anesthesia caused a more significant prolongation of the QTc interval in patients with diabetes than in those without.N

Effects of interfacial area and energetic barrier on thermoelectric performance of PEDOT:PSS–MXene composite films

Thermoelectric (TE) devices based on conducting polymers have significant potential for low-temperature energy harvesting. To enhance the TE performance, the incorporation of low-dimensional inorganic fillers into the polymer matrix has been considered as a promising strategy by exploiting the energy filtering effect. Since the energy filtering effect is strongly influenced by the carrier scattering at the interface between polymer and inorganic fillers, the TE properties are likely to be affected by the interfacial properties of two constituents. In this study, we investigated the TE performance in the composite films of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and two-dimensional Ti _3 C _2 MXene, in order to reveal the effects of the interfacial area and the energetic barrier on the TE performance by controlling the MXene sizes and the oxidation level of PEDOT:PSS. We found that the composite film with smaller MXene exhibits a higher power factor ( PF) than that with larger MXene, originating from the increased interfacial area which facilitates the energy filtering effect. We also showed that an optimal energy barrier (0.14 eV) between PEDOT:PSS and MXene can accelerate the energy filtering effect, which allows to maximize the PF of the composite films up to 69.4 μ W m ^−1 K ^−2 . We believe that our study not only contributes to the development of the composite-based TE devices utilizing the energy filtering effect, but also helps to understand the charge transport in polymer–inorganic composites