19 research outputs found

    1,2-Bis[5-(2,2′-dicyano­vinyl)-2-n-pentyl-3-thien­yl]-3,3,4,4,5,5-hexa­fluoro­cyclo­pent-1-ene: a new photochromic diaryl­ethene compound

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    The title compound, C31H26F6N4S2, is a new photochromic dithienylethene with dicyano­vinyl subsitituents. In the crystal structure, the mol­ecule adopts a photoactive anti­parallel conformation, with two n-pentyl groups located on opposite sides of the cyclo­pentene ring. The cyclo­pentene ring assumes an envelope conformation. The distance between the two reactive C atoms on the thio­phene rings is 3.834 (7) Å. One of the n-pentyl groups is disordered over two positions; the site occupancy factors are ca 0.7 and 0.3

    3-(4-{3,3,4,4,5,5-Hexafluoro-2-[5-(3-methoxy­phen­yl)-2-methyl-3-thien­yl]cyclo­pent-1-en­yl}-5-methyl-2-thien­yl)benzonitrile

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    The title compound, C29H19F6NOS2, is a new unsymmetrical photochromic diarylethene derivative with different meta-phenyl substituents. The distance between the two reactive (i.e. can be irradiated to form a new chemical bond) C atoms is 3.501 (4) Å; the dihedral angles between the mean plane of the main central cyclo­pentene ring and the thio­phene rings are 47.7 (5) and 45.1 (2)°, and those between the thio­phene rings and the adjacent benzene rings are 29.4 (2) and 28.4 (3)°. The three C atoms and the F atoms of hexa­fuorocyclo­pentene ring are disordered over two positions, with site-occupancy factors of 0.751 (4) and 0.249 (4)

    Differential expression of ozone-induced gene during exposures to salt stress in Polygonum sibiricum Laxm leaves, stem and underground stem

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    The response of plants to environmental stresses is characterized by a number of physiological and biochemical changes that ultimately result from the selective increase or decrease in the biosynthesis of a large number of distinct proteins. In this report, we describe the characterization of an ozoneinduced transcript, PcOZI-1, which has been identified from Polygonum sibiricum Laxm by the rapid amplification of cDNA ends method (RACE). PcOZI-1 mRNA in untreated plants was detected at low levels in underground stem, leaves and at higher levels in stem. PcOZI-1 mRNA accumulation was transiently induced in stem 7-fold within the first 8 h of 3% NaHCO3 treatment. PcOZI-1 mRNA accumulation was also induced 22-fold in underground stem after 72 h. Sequence analysis of PcOZI-1 revealed that it encodes a 8.45 kDa basic protein that contains a putative signal peptide. Our results suggest that PcOZI-1 represents a novel stress-related protein that accumulates in response to the production of active oxygen species.Keywords: Polygonum sibiricum Laxm, PcOZI-1, rapid amplification of cDNA ends, gene expressionAfrican Journal of Biotechnology Vol. 9(33), pp. 5338-5342, 16 August, 201

    Hf(OTf)<sub>4</sub>-Catalyzed Three-Component Synthesis of <i>N</i>-Carbamate-Protected β-Amino Ketones

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    Hafnium(IV) triflate (Hf(OTf)4) has been identified as a potent catalyst for the direct three-component synthesis of β-carbamate ketones. This new method, featuring a low catalyst loading, fast reaction rate, and solvent-free conditions, provided facile access to a diversity of carbamate-protected Mannich bases. A mechanistic investigation indicated that the three-component reaction proceeds via sequential aldol condensation and aza-Michael addition, but not the Mannich-type pathway

    An Improved Approach for Practical Synthesis of 5-Hydroxymethyl-2&prime;-deoxycytidine (5hmdC) Phosphoramidite and Triphosphate

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    5-Hydroxymethyl-2&prime;-deoxycytidine (5hmdC) phosphoramidite and triphosphate are important building blocks in 5hmdC-containing DNA synthesis for epigenetic studies. However, efficient and practical methods for the synthesis of these compounds are still limited. The current research provides an intensively improved synthetic method that enables the preparation of commercially available cyanoethyl-protected 5hmdC phosphoramidite with an overall yield of 39% on 5 g scale. On the basis of facile and efficient accesses to cyanoethyl protected-5hmdU and 5hmdC intermediates, two efficient synthetic routes for 5hmdC triphosphate were also developed

    A W band second harmonic gyrotron oscillator

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    Simulation of a diode type magnetron injection gun for a W-band CW gyrotron

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    In this paper, the simulation and design of a diode type magnetron injection gun (MIG) for a W-band CW gyrotron oscillator is presented. The simulation of the MIG, operating at the voltage of 55kV and the current of 4A, is finished with the help of a trajectory program EGUN. The simulation results indicate that the velocity ratio with velocity spread of less than 2.5% is 1.43. ? 2014 IEEE.EI

    Significant enhancement of C<sub>2</sub>H<sub>2</sub>/C<sub>2</sub>H<sub>4</sub> separation by a photochromic diarylethene unit: a temperature- and light-responsive separation switch

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    A dual temperature- and light-responsive C2H2/C2H4 separation switch in a diarylethene Metal–organic Framework (MOF) is presented. At 195 K and 100 kPa this MOF shows ultrahigh C2H2/C2H4 selectivity of 47.1, which is almost 21.4 times larger than the corresponding value of 2.2 at 293 K and 100 kPa or 15.7 times larger than the value of 3.0 for the material under UV at 195 K and 100 kPa. The origin of this unique control in C2H2/C2H4 selectivity, as unveiled by density functional calculations, is due to a guest discriminatory gate-opening effect from the diarylethene unit
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