Inhibition of LPS-induced cyclooxygenase 2 and nitric oxide production by transduced PEP-1-PTEN fusion protein in Raw 264.7 macrophage cells

Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a tumor suppressor. Although it is well known to have various physiological roles in cancer, its inhibitory effect on inflammation remains poorly understood. In the present study, a human PTEN gene was fused with PEP-1 peptide in a bacterial expression vector to produce a genetic in-frame PEP-1-PTEN fusion protein. The expressed and purified PEP-1-PTEN fusion protein were transduced efficiently into macrophage Raw 264.7 cells in a time- and dose-dependent manner when added exogenously in culture media. Once inside the cells, the transduced PEP-1-PTEN protein was stable for 24 h. Transduced PEP-1-PTEN fusion protein inhibited the LPS-induced cyclooxygenase 2 (COX-2) and iNOS expression levels in a dose-dependent manner. Furthermore, transduced PEP-1-PTEN fusion protein inhibited the activation of NF-κB induced by LPS. These results suggest that the PEP-1-PTEN fusion protein can be used in protein therapy for inflammatory disorders.     

Atomic-scale phase coexistence and fluctuation at the quasi-one-dimensional metal-insulator transition

Scanning tunneling microscopy of a quasi-one-dimensional (1D) metal-insulator transition in an In nanowire array on the Si(111) surface reveals unprecedented details in the transition dynamics. The transition proceeds in microscopic first order, namely, through the domain-by-domain conversion at the nanoscale, from the metallic to the insulating phase or vice versa. The definition of domains and their effective transition temperatures (Tc) are strongly correlated with the distribution of defects. Below Tc, the condensation and the fluctuation of 1D charge density waves are observed within the isolated metallic domains, as well as at the domain boundaries. The appearance of such isolated condensates suggests a strong intrawire coupling: a manifestation of the 1D nature of the critical fluctuation, as well as the origin of the first-order transition.     

Impregnation of tungstophosphoric acid on poly(methacrylamide-co-methyl methacrylate) and its acid catalytic activity in TMB alkylation

A poly(methacrylamide-co-methylmethacrylate) (abbreviated PMAA-MMA) polymer support was studied for supporting a heteropolyacid (tungstophosphoric acid, H₃PW₁₂O₄₀) with its surface positively charged in the polymerization step. PMAA-MMA supports could be obtained in a porous form by eliminating template reagent molecules (benzylmalonic acid) combined with properly selected monomer (methacrylamide). The amount of amine groups in PMAA-MMA directly determined the amount of H₃PW₁₂O₄₀ impregnated, because the amine groups induced a positive charge on the PMAA-MMA surface. Finally, H₃PW₁₂O₄₀/PMAA-MMA showed better acid catalytic activities than unsupported H₃PW₁₂O₄₀ in alkylation of 1,3,5-trimethylbenzene with cyclohexene, which confirmed that PMAA-MMA supported H₃PW₁₂O₄₀ effectively.     

Synthesis and characterization of a bis-methanofullerene-4-nitro-α-cyanostilbene dyad as a potential acceptor for high-performance polymer solar cells

We report the synthesis, characterization, and electrochemical properties of bis-PCBM dyad containing 4-nitro-α-cyanostilbene units for potential usage in efficient organic solar cells. The bis-PCBM dyad is fully characterized by NMR, UV–vis absorption, and electrochemical cyclic voltammetry. It is found that the presence of 4-nitro-α-cyanostilbenes affects the cyclic voltammetry and absorption spectrum very little. Whereas the 56 π-electron system in the bis-functionalized fullerene cage significantly influences on the electrochemical and photophysical properties, resulting in up-shifted LUMO and wider absorption compared to PCBM. Although the efficiencies of both conventional and the inverted cells based on P3HT/bis-PCBM dyad as the preliminary results are low in comparison with the optimized high-performance PSCs, it is believed that the efficiency would be improved through successful device optimization of P3HT/bis-PCBM dyad cells.     

Comparison between evaporative light scattering detection and charged aerosol detection for the analysis of saikosaponins

Saikosaponins are triterpene saponins derived from the roots of Bupleurum falcatum L. (Umbelliferae), which has been traditionally used to treat fever, inflammation, liver diseases, and nephritis. It is difficult to analyze saikosaponins using HPLC-UV due to the lack of chromophores. Therefore, evaporative light scattering detection (ELSD) is used as a valuable alternative to UV detection. More recently, a charged aerosol detection (CAD) method has been developed to improve the sensitivity and reproducibility of ELSD. In this study, we compared CAD and ELSD methods in the simultaneous analysis of 10 saikosaponins, including saikosaponins-A, -B₁, -B₂, -B₃, -B₄, -C, -D, -G, -H and -I. A mixture of the 10 saikosaponins was injected into the Ascentis^® Express C18 column (100 mm × 4.6 mm, 2.7 μm) with gradient elution and detection with CAD and ELSD by splitting. We examined various factors that could affect the sensitivity of the detectors including various concentrations of additives, pH and flow rate of the mobile phase, purity of nitrogen gas and the CAD range. The sensitivity was determined based on the signal-to-noise ratio. The best sensitivity for CAD was achieved with 0.1 mM ammonium acetate at pH 4.0 in the mobile phase with a flow rate of 1.0 mL/min, and the CAD range at 100 pA, whereas that for ELSD was achieved with 0.01% acetic acid in the mobile phase with a flow rate at 0.8 mL/min. The purity of the nitrogen gas had only minor effects on the sensitivities of both detectors. Finally, the sensitivity for CAD was two to six times better than that of ELSD. Taken together, these results suggest that CAD provides a more sensitive analysis of the 10 saikosaponins than does ELSD.     

3D reconstruction of a carotid bifurcation from 2D transversal ultrasound images

Visualizing and analyzing the morphological structure of carotid bifurcations are important for understanding the etiology of carotid atherosclerosis, which is a major cause of stroke and transient ischemic attack. For delineation of vasculatures in the carotid artery, ultrasound examinations have been widely employed because of a noninvasive procedure without ionizing radiation. However, conventional 2D ultrasound imaging has technical limitations in observing the complicated 3D shapes and asymmetric vasodilation of bifurcations. This study aims to propose image-processing techniques for better 3D reconstruction of a carotid bifurcation in a rat by using 2D cross-sectional ultrasound images. A high-resolution ultrasound imaging system with a probe centered at 40 MHz was employed to obtain 2D transversal images. The lumen boundaries in each transverse ultrasound image were detected by using three different techniques; an ellipse-fitting, a correlation mapping to visualize the decorrelation of blood flow, and the ellipse-fitting on the correlation map. When the results are compared, the third technique provides relatively good boundary extraction. The incomplete boundaries of arterial lumen caused by acoustic artifacts are somewhat resolved by adopting the correlation mapping and the distortion in the boundary detection near the bifurcation apex was largely reduced by using the ellipse-fitting technique. The 3D lumen geometry of a carotid artery was obtained by volumetric rendering of several 2D slices. For the 3D vasodilatation of the carotid bifurcation, lumen geometries at the contraction and expansion states were simultaneously depicted at various view angles. The present 3D reconstruction methods would be useful for efficient extraction and construction of the 3D lumen geometries of carotid bifurcations from 2D ultrasound images.     

Gold-catalyzed ring expansions of 1-alkynylcyclobutanol derivatives via tandem hydration and α-ketol rearrangement

We report herein the gold-catalyzed tandem hydration/α-ketol rearrangement of 1-alkynylcyclobutanol derivatives, leading to cyclopentanones bearing an α-hydroxy substituted quaternary center. In the presence of water, coordination of gold catalyst onto alkynyl moiety triggers hydration rather than a direct ring expansion, which followed by unprecedented Au-catalyzed α-ketol rearrangement. The details and the scope of this method are presented.     

Band-structure engineering of gold atomic wires on silicon by controlled doping

We report on the systematic tuning of the electronic band structure of atomic wires by controlling the density of impurity atoms. The atomic wires are self-assembled on Si(111) by substitutional gold adsorbates and extra silicon atoms are deposited as the impurity dopants. The one-dimensional electronic band of gold atomic wires, measured by angle-resolved photoemission, changes from a fully metallic to semiconducting one with its band gap increasing above 0.3 eV along with an energy shift as a linear function of the Si dopant density. The gap opening mechanism is suggested to be related to the ordering of the impurities.     

Novel pathway to the growth of diamond on cubic beta-SiC(001)

By carrying out first-principles calculations on diamond-forming processes, we predict a method for the heteroepitaxial growth of diamond on cubic beta-SiC(001). In the method, we used two processes: (i) the preformation of an sp(3)-like surface configuration of beta-SiC(001) by the adsorption of group-V surfactants; (ii) the successive growth of diamond by the segregation of the surfactants onto a surface and the desorption of surface hydrogen. Analyzing the segregation energies, we found that the atomic size effect plays a crucial role in the surfactant-mediated growth of diamond on beta-SiC(001).