Light-driven phase transition in a cubic-phase-forming binary system composed of 4'-n-docosyloxy-3'-nitrobiphenyl-4-carboxylic acid and an azobenzene derivative

Binary mixtures were prepared from an azobenzene derivative and a liquid-crystal (LC) compound that exhibits smectic?C (SmC) and bicontinuous cubic (Cub(bi)) LC phases. Reversible switching between the two phases in response to UV-light irradiation was observed. This light-driven SmC-to-Cub(bi) transition is the first example showing the increased dimensionality of molecular ordering with isomerization of azobenzenes (see figure).     

强碱阴离子交换树脂及碱性洗脱剂的离子排阻/阴离子交换色谱法同时测定NH4+ ，NO2-和NO3-（英文）

Ion-exclusion/anion-exchange chromatography(IEC/AEC) on a combination of a strongly basic anion-exchange resin in the OH——form with basic eluent has been developed.The separation mechanism is based on the ion-exclusion/penetration effect for cations and the anion-exchange effect for anions to anion-exchange resin phase.This system is useful for simultaneous separation and determination of ammonium ion(NH+4),nitrite ion(NO-2),and nitrate ion(NO-3) in water samples.The resolution of analyte ions can be manipulated by changing the concentration of base in eluent on a polystyrene-divinylbenzene based strongly basic anion-exchange resin column.In this study,several separation columns,which consisted of different particle sizes,different functional groups and different anion-exchange capacities,were compared.As the results,the separation column with the smaller anion-exchange capacity(TSKgel Super IC-Anion) showed well-resolved separation of cations and anions.In the optimization of the basic eluent,lithium hydroxide(LiOH) was used as the eluent and the optimal concentration was concluded to be 2 mmol/L,considering the resolution of analyte ions and the whole retention times.In the optimal conditions,the relative standard deviations of the peak areas and the retention times of NH+4,NO-2,and NO-3 ranged 1.28%-3.57% and 0.54%-1.55%,respectively.The limits of detection at signal-to-noise of 3 were 4.10 μmol/L for NH+4,1.87 μmol/L for NO-2 and 2.83 μmol/L for NO-3.     

High-energy 'composite' layered manganese-rich cathode materials via controlling Li2MnO3 phase activation for lithium-ion batteries

The 'composite' layered materials for lithium-ion batteries have recently attracted great attention owing to their large discharge capacities. Here, the 0.5Li(2)MnO(3)·0.5LiMn(0.42)Ni(0.42)Co(0.16)O(2)'composite' layered manganese-rich material is prepared and characterized by the synchrotron X-ray powder diffraction (SXPD). The relationship between its electrochemical performance and its 'composite' components, the Li(2)MnO(3) phase activation process during cycling and the cycle stability of this material at room temperature are elucidated based on its kinetic controlled electrochemical properties, dQ/dV curves and Raman scattering spectroscopies associated with different initial charge-discharge current densities (5 mA g(-1), 20 mA g(-1) and 50 mA g(-1)), cut-off voltages (4.6 V and 4.8 V) and cycle numbers (50 cycles and 150 cycles). Furthermore, its reaction pathways are tracked via a firstly introduced integrated compositional phase diagram of four components, Li(2)MnO(3), LiMn(0.42)Ni(0.42)Co(0.16)O(2), MO(2) (M = Mn(1-α-β)Ni(α)Co(β); 0 ≤α≤ 5/12, 0 ≤β≤ 1/6) and LiMnO(2), which turns out to be a very important guiding tool for understanding and utilizing this 'composite' material.     

Blockade of inflammatory responses by a small-molecule inhibitor of the Rac activator DOCK2

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Highlights? CPYPP binds to DOCK2 DHR-2 domain and inhibits its catalytic activity ? CPYPP inhibits DOCK2-mediated Rac activation in cells ? The structural features of CPYPP required for its inhibitory effect were revealed ? CPYPP inhibits lymphocyte migration and activation in vitro and in vivo     

Asymmetric total syntheses of (+)-mycoepoxydiene and related natural product (-)-1893A: application of one-pot ring-opening/cross/ring-closing metathesis to construct their 9-oxabicyclo[4.2.1]nona-2,4-diene skeleton

The total syntheses of (+)-mycoepoxydiene and (-)-1893A have been completed. The present synthetic strategy features the use of one-pot ring-opening/cross metathesis (ROM/CM) followed by a ring-closing metathesis (RCM) reaction, allowing for the concise construction of the 9-oxabicyclo[4.2.1]nona-2,4-diene framework from a 7-oxabicyclo[2.2.1]hept-2-ene derivative and 1,3-butadiene. The sequential metathesis product was converted into (+)-mycoepoxydiene through the oxidative rearrangement of a furfuryl alcohol to a pyranone, thereby establishing its absolute stereochemistry. From the common intermediate, a structurally related natural product (-)-1893A was also synthesized via the vinylogous aldol reaction.     

Prolongation of the active lifetime of a biomolecular motor for in vitro motility assay by using an inert atmosphere

Over the last few decades, the in vitro motility assay has been performed to probe the biophysical and chemo-mechanical properties as well as the self-organization process of biomolecular motor systems such as actin-myosin and microtubule-kinesin. However, aggression of the reactive oxygen species (ROS) and concomitant termination of the activity of biomolecular motors during investigation remains a drawback of this assay. Despite enzymatic protection that makes use of a combination of glucose, glucose oxidase, and catalase, the active lifetime of biomolecular motors is found to be only a few hours and this short lifetime restricts further study on those systems. We have solved this problem by using a newly developed system of the in vitro motility assay that is conducted in an inert nitrogen gas atmosphere free of ROS. Using microtubule-kinesin as a model system we have shown that our system has prolonged the active lifetime of the biomolecular motor until several days and even a week by protecting it from oxidative damage.     

X-ray absorption, photoemission spectroscopy, and Raman scattering analysis of amorphous tantalum oxide with a large extent of oxygen nonstoichiometry

The electronic structure and modification of the local interatomic structure of a reactive sputtered amorphous tantalum oxide (a-TaO(x)) thin film with the variation of oxygen nonstoichiometry, x in a-TaO(x) have been investigated by X-ray absorption spectroscopy (XAS), X-ray photoemission spectroscopy (XPS), Raman scattering spectroscopy, and Rutherford back scattering spectroscopy. A parallel chemical shift of Ta4f(7/2) and O1s core levels observed with the variation of x indicates the Fermi level shift by reduction and oxidation in the framework of the rigid band model. Extended X-ray absorption fine structure (EXAFS) suggests both the increase of average coordination number of the first Ta-O shell in polyhedra and a considerable reduction of the average Ta-O bond length with the increase of x. The relative intensity of Raman shift peaks at 670 cm(-1) and 815 cm(-1), corresponding to Ta-O stretching of TaO(6) octahedra and TaO(5) probably with a pyramidal form, respectively, drastically changes between x = 2.47 to 1.86, suggesting the change in the predominant polyhedron from TaO(6) to TaO(5) with a modification in multiplicity of oxygen by the reorganization of the polyhedral network.     

Size distribution and characteristics of chemical components in ambient particulate matter.

Ambient particulate matter and gas in Kyoto were investigated by gravimetric analysis, X-ray fluorescence spectrometry, and ion chromatography in order to clarify their behavior and origin. The size distribution and characteristics of the chemical components in ambient particulates collected on PTFE membrane filters using an Andersen air sampler were examined from August 2001 to April 2004. A four-stage filter pack method was used to sample the atmosphere for the determination of gas (SO2, HNO3, HCl, NH3) and particulate matter (SO42, NO3, Cl-, Na+, K+, Ca2+, Mg2+, NH4+) concentrations from October 2002 to April 2004. The concentration of SPM mass was in the range of 6.7 - 80.2 microg/m3. The size distributions of SPM mass were bimodal, peaking at around 0.65 - 1.1 and 3.3 - 4.7 microm, and 40 - 85% of SPM mass was fine particles (< 2.1 microm). Na, Mg, Al, Si, Ca, Cl, and Fe were mainly present in coarse particles (2.1 to 11.0 microm), while S was present in fine particles. The concentrations of Al, Si, Ca, Mg, and Fe in fine particles increased from March to April in 2002, and those in coarse particulates increased in November 2002 and from March to April in 2004. This may be the effect of the continental yellow sand "Kosa." The differences in the size distributions of Al, Si, Ca, Mg, and Fe in particles may depend on differences in their place of occurrence and course of transport from China to Japan. The concentration of HCl gas was higher than that of particulate chloride ion in summer. Nitric acid gas existed at higher concentrations in summer, but fine particulate nitrate ion was observed in winter. The gaseous-to-fine aerosol nitrate fraction became higher at warmer temperatures. Coarse sulfate was below 10%, and SO2 gas and fine particulate sulfate were above 90%.     

Multiplex amplified product-length polymorphism analysis of 36 mitochondrial single-nucleotide polymorphisms for haplogrouping of East Asian populations

We present a reliable, rapid, and economical multiplex amplified product-length polymorphism (APLP) method for analyzing the haplogroup-diagnostic mitochondrial single-nucleotide polymorphisms (mtSNPs) in East Asian populations. By examining only 36 haplogroup-specific mtSNPs in the coding region by using four 9-multiplex polymerase chain reaction (PCR) and subsequent electrophoresis, we could safely assign 1815 individuals from 8 populations of Japanese, Korean, Chinese, and Germans to 45 relevant haplogroups. This multiplex APLP analysis of coding-region mtSNPs for haplogrouping is especially useful not only for molecular phylogenetic studies but also for large-scale association studies due to its rapid and economical nature. This is the first panel of mtSNPs in the coding region to be used for haplogrouping of East Asian populations.     

Syntheses and structures of hypervalent pentacoordinate carbon and boron compounds bearing an anthracene skeleton--elucidation of hypervalent interaction based on X-ray analysis and DFT calculation

Pentacoordinate and tetracoordinate carbon and boron compounds (27, 38, 50-52, 56-61) bearing an anthracene skeleton with two oxygen or nitrogen atoms at the 1,8-positions were synthesized by the use of four newly synthesized tridentate ligand precursors. Several carbon and boron compounds were characterized by X-ray crystallographic analysis, showing that compounds 27, 56-59 bearing an oxygen-donating anthracene skeleton had a trigonal bipyramidal (TBP) pentacoordinate structure with relatively long apical distances (ca. 2.38-2.46 A). Despite the relatively long apical distances, DFT calculation of carbon species 27 and boron species 56 and experimental accurate X-ray electron density distribution analysis of 56 supported the existence of the apical hypervalent bond even though the nature of the hypervalent interaction between the central carbon (or boron) and the donating oxygen atom was relatively weak and ionic. On the other hand, X-ray analysis of compounds 50-52 bearing a nitrogen-donating anthracene skeleton showed unsymmetrical tetracoordinate carbon or boron atom with coordination by only one of the two nitrogen-donating groups. It is interesting to note that, with an oxygen-donating skeleton, the compound 61 having two chlorine atoms on the central boron atom showed a tetracoordinate structure, although the corresponding compound 60 with two fluorine atoms showed a pentacoordinate structure. The B-O distances (av 2.29 A) in 60 were relatively short in comparison with those (av 2.44 A) in 59 having two methoxy groups on the central boron atom, indicating that the B-O interaction became stronger due to the electron-withdrawing nature of the fluorine atoms.