Vibrational spectra and normal co-ordinate analysis of 2-aminopyridine and 2-amino picoline

The Fourier transform infrared (FT-IR) and Raman (FT-R) spectra of 2-aminopyridine and 2-amino picoline were recorded and the observed frequencies were assigned to various modes of vibration in terms of fundamentals by assuming Cs point group symmetry. A normal co-ordinate analysis was also carried out for the proper assignment of the vibrational frequencies using simple valence force field. A complete vibrational analysis is presented here for the molecules and the results are briefly discussed.     

Interfacial electronic structure of molybdenum oxide on the fullerene layer,a potential hole-injecting layer in inverted top-emitting organic light-emitting diodes

The interfacial electronic structures of molybdenum oxide (MoO_x) deposited on fullerene (C₆₀) which could be used as a hole-injecting layer in inverted top-emitting organic light-emitting diodes (TE-OLEDs) were investigated by photoemission spectroscopy. The hole-injecting barrier height (Φ_B^h) at each interface investigated by an ultraviolet photoemission spectroscopy was reduced to from 1.4 to 0.1 eV as the thickness of MoO_x (Θ_MoOx) was increased from 0.1 to 5.0 nm on C₆₀. In these interface system, the sign of vacuum-level shift, highest occupied molecular orbital (HOMO)-level shift, and core-level shifts were all positive indicating that the interface mechanism is attributed to the work-function differences due to a band bending at these interfaces. Moreover, the near-edge X-ray absorption fine structure spectra at carbon K-edge did not show any structural modification as well as any chemical reaction at the MoO_x-on-C₆₀ interfaces when Θ_MoOx was changed on C₆₀. From these results, the inverted TE-OLED with C₆₀ (5.0 nm)/MoO_x (5.0 nm) showed the power efficiency of 1.7 lm/W at a luminance of about 1000 cd/m² and the maximum luminance of about 76.000 cd/m² at the bias voltage of 11.0 V. It exhibited the highest performance among the inverted TE-OLEDs fabricated as a function of MoO_x thickness from 0 to 5.0 nm.     

Hopping domain wall induced by paired adatoms on an atomic wire: si(111)-(5 x 2)-Au

We observed an inhomogeneous fluctuation along one-dimensional atomic wires self-assembled on a Si(111) surface using scanning tunneling microscopy. The fluctuation exhibits dynamic behavior at room temperature and is observed only in a specific geometric condition; the spacing between two neighboring adatom defects is discommensurate with the wire lattice. Upon cooling, the dynamic fluctuation freezes to show the existence of an atomic-scale dislocation or domain wall induced by such "unfavorably" paired adatoms. The microscopic characteristics of the dynamic fluctuation are explained in terms of a hopping solitonic domain wall, and a local potential for this motion imposed by the adatoms is quantified.     

Statistical Optimization of 1,3-Propanediol (1,3-PD) Production from Crude Glycerol by Considering Four Objectives: 1,3-PD Concentration,Yield, Selectivity,and Productivity

This study investigated the biological conversion of crude glycerol generated from a commercial biodiesel production plant as a by-product to 1,3-propanediol (1,3-PD). Statistical analysis was employed to derive a statistical model for the individual and interactive effects of glycerol, (NH₄)₂SO₄, trace elements, pH, and cultivation time on the four objectives: 1,3-PD concentration, yield, selectivity, and productivity. Optimum conditions for each objective with its maximum value were predicted by statistical optimization, and experiments under the optimum conditions verified the predictions. In addition, by systematic analysis of the values of four objectives, optimum conditions for 1,3-PD concentration (49.8 g/L initial glycerol, 4.0 g/L of (NH₄)₂SO₄, 2.0 mL/L of trace element, pH 7.5, and 11.2 h of cultivation time) were determined to be the global optimum culture conditions for 1,3-PD production. Under these conditions, we could achieve high 1,3-PD yield (47.4%), 1,3-PD selectivity (88.8%), and 1,3-PD productivity (2.1/g/L/h) as well as high 1,3-PD concentration (23.6 g/L).     

Cost‐Effective,High‐Performance Porous‐Organic‐Polymer Conductors Functionalized with Sulfonic Acid Groups by Direct Postsynthetic Substitution

We demonstrate the facile microwave‐assisted synthesis of a porous organic framework 1 and the sulfonated solid ( 1S ) through postsubstitution. Remarkably, the conductivity of 1S showed an approximately 300‐fold enhancement at 30 °C as compared to that of 1 , and reached 7.72×10^?2 S cm^?1 at 80 °C and 90 % relative humidity. The superprotonic conductivity exceeds that observed for any conductive porous organic polymer reported to date. This material, which is cost‐effective and scalable for mass production, also revealed long‐term performance over more than 3 months without conductivity decay.     

Cost‐Effective,High‐Performance Porous‐Organic‐Polymer Conductors Functionalized with Sulfonic Acid Groups by Direct Postsynthetic Substitution

We demonstrate the facile microwave‐assisted synthesis of a porous organic framework 1 and the sulfonated solid ( 1S ) through postsubstitution. Remarkably, the conductivity of 1S showed an approximately 300‐fold enhancement at 30 °C as compared to that of 1 , and reached 7.72×10⁻² S cm⁻¹ at 80 °C and 90 % relative humidity. The superprotonic conductivity exceeds that observed for any conductive porous organic polymer reported to date. This material, which is cost‐effective and scalable for mass production, also revealed long‐term performance over more than 3 months without conductivity decay.     

Coptidis rhizoma extract protects against cytokine-induced death of pancreatic beta-cells through suppression of NF-kappaB activation

We demonstrated previously that Coptidis rhizoma extract (CRE) prevented S-nitroso-N-acetylpenicillamine-induced apoptotic cell death via the inhibition of mitochondrial membrane potential disruption and cytochrome c release in RINm5F (RIN) rat insulinoma cells. In this study, the preventive effects of CRE against cytokine-induced beta-cell death was assessed. Cytokines generated by immune cells infiltrating pancreatic islets are crucial mediators of beta-cell destruction in insulin-dependent diabetes mellitus. The treatment of RIN cells with IL-1beta and IFN-gamma resulted in a reduction of cell viability. CRE completely protected IL-1beta and IFN-gamma-mediated cell death in a concentration-dependent manner. Incubation with CRE induced a significant suppression of IL-1beta and IFN-gamma-induced nitric oxide (NO) production, a finding which correlated well with reduced levels of the iNOS mRNA and protein. The molecular mechanism by which CRE inhibited iNOS gene expression appeared to involve the inhibition of NF-kappaB activation. The IL-1beta and IFN-gamma-stimulated RIN cells showed increases in NF-kappaB binding activity and p65 subunit levels in nucleus, and IkappaB alpha degradation in cytosol compared to unstimulated cells. Furthermore, the protective effects of CRE were verified via the observation of reduced NO generation and iNOS expression, and normal insulin-secretion responses to glucose in IL-1beta and IFN-gamma-treated islets.     

Self-diffusion of reversibly aggregating spheres

Reversible diffusion limited cluster aggregation of hard spheres with rigid bonds was simulated and the self-diffusion coefficient was determined for equilibrated systems. The effect of increasing attraction strength was determined for systems at different volume fractions and different interaction ranges. It was found that the slowing down of the diffusion coefficient due to crowding is decoupled from that due to cluster formation. The diffusion coefficient could be calculated from the cluster size distribution and became zero only at infinite attraction strength when permanent gels are formed. It is concluded that so-called attractive glasses are not formed at finite interaction strength.     

Impact behaviors of a millimetric impinging drop on a superheated Al alloy surface

Journal of Visualization - The impact behaviors and boiling regimes of millimetric water droplets on an aluminum alloy are experimentally investigated with varying surface temperatures. Compared to...     

Point defects along metallic atomic wires on vicinal Si surfaces: Si(5 5 7)–Au and Si(5 5 3)–Au

Point defects on the metallic atomic wires induced by Au adsorbates on vicinal Si surfaces were investigated using scanning tunneling microscopy and spectroscopy (STM and STS). High-resolution STM images revealed that there exist several different types of defects on the Si(5 5 7)–Au surface, which are categorized by their apparent bias-dependent images and compared to the previous report on Si(5 5 3)–Au [Phys. Rev. B (2007) 205325]. The chemical characteristics of these defects were investigated by monitoring them upon the variation of the Au coverage and the adsorption of water molecules. The chemical origins and the tentative atomic structures of the defects are suggested as Si adatoms (and dimers) in different registries, the Au deficiency on terraces, and water molecules adsorbed dissociatively on step edges, respectively. STS measurements disclosed the electronic property of the majority kinds of defects on both Si(5 5 7)–Au and Si(5 5 3)–Au surfaces. In particular, the dominating water-induced defects on both surfaces induce a substantial band gap of about 0.5 eV in clear contrast to Si adatom-type defects. The conduction channels along the metallic step-edge chains thus must be very susceptible to the contamination through the electronic termination by the water adsorption.