Transcript regulation in response to high salinity was investigated for salt-tolerant rice (var Pokkali) with microarrays including 1728 cDNAs from libraries of salt-stressed roots. NaCl at 150 mM reduced photosynthesis to one tenth of the prestress value within minutes. Hybridizations of RNA to microarray slides probed for changes in transcripts from 15 min to 1 week after salt shock. Beginning 15 min after the shock, Pokkali showed upregulation of transcripts. Approximately 10% of the transcripts in Pokkali were significantly upregulated or downregulated within 1 hr of salt stress. The initial differences between control and stressed plants continued for hours but became less pronounced as the plants adapted over time. The interpretation of an adaptive process was supported by the similar analysis of salinity-sensitive rice (var IR29), in which the immediate response exhibited by Pokkali was delayed and later resulted in downregulation of transcription and death. The upregulated functions observed with Pokkali at different time points during stress adaptation changed over time. Increased protein synthesis and protein turnover were observed at early time points, followed by the induction of known stress-responsive transcripts within hours, and the induction of transcripts for defense-related functions later. After 1 week, the nature of upregulated transcripts (e.g., aquaporins) indicated recovery.
To elucidate the structures of C60F36 and C60F48, X-ray diffraction and electron diffraction experiments have
been performed. It was found that the X-ray diffractograms of C60F36 and C60F48 at room temperature are
indexed by bcc and bct lattices, respectively. In situ X-ray diffraction experiments at high temperatures have
been also undertaken. The bct to fcc phase transition of C60F48 was observed. The mechanism of the transition
and the stabilities of the structures of fluorinated fullerenes are discussed.
The electrochemical behavior of highly crystallized single-walled carbon nanotubes (SWCNTs), having a small diameter distribution, is investigated by cyclic voltammetry (CV), using triethylmethylammonium tetrafluoroborate in propylene carbonate as an electrolyte. Unlike the CV curves previously observed by other researchers and referred to as the "butterfly" shape, the CV curve observed in the present study shows large bulges on both sides of the rest potential, thereby resembling a dumbbell. By comparison of the electronic density of states (DOS) of SWCNTs and the dumbbell CV shape, it was determined that the drastic increase of current in the dumbbell shape can be explained by the van Hove singularity in the DOS of the semiconducting SWCNTs in the sample. To validate the explanation, we performed separation of metallic and semiconducting SWCNTs by the density gradient ultracentrifugation method and measured CV curves of the two separated samples. As was expected, the two SWCNT samples showed completely different CV profiles corresponding to each DOS shape. In addition, ion adsorption inside the nanotube is discussed with attention to the change in CV curves with increasing sweep rate.
We investigated the electrochemical lithium-ion storage properties of 9,10-anthraquinone (AQ) and 9,10-phenanthrenequinone (PhQ) molecules encapsulated in the inner hollow core of single-walled carbon nanotubes (SWCNTs). The structural properties of the obtained encapsulated systems were characterized by electron microscopy, synchrotron powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. We found that almost all quinone molecules encapsulated in the SWCNTs can store Li-ions reversibly. Interestingly, the undesired capacity fading, which comes from the dissolution of quinone molecules into the electrolyte, was suppressed by the encapsulation. It was also found that the overpotential of AQ was decreased by the encapsulation, probably due to the high-electric conductivity of SWCNTs.
Expanding the range of supercapacitor operation to temperatures above 100°C is important because this would enable capacitors to operate under the severe conditions required for next-generation energy storage devices. In this study, we address this challenge by the fabrication of a solid-state supercapacitor with a proton-conducting Sn0.95Al0.05H0.05P2O7 (SAPO)-polytetrafluoroethylene (PTFE) composite electrolyte and a highly condensed H3PO4 electrode ionomer. At a temperature of 200°C, the SAPO-PTFE electrolyte exhibits a high proton conductivity of 0.02 S cm−1 and a wide withstanding voltage range of ±2 V. The H3PO4 ionomer also has good wettability with micropore-rich activated carbon, which realizes a capacitance of 210 F g−1 at 200°C. The resulting supercapacitor exhibits an energy density of 32 Wh kg−1 at 3 A g−1 and stable cyclability after 7000 cycles from room temperature to 150°C.
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