Downstream molecular events in the altered profiles of lysophosphatidic acid-induced cAMP in senescent human diploid fibroblasts

Lysophosphatidic acid (LPA) is a phospholipid growth factor that acts through G-protein-coupled receptors. Previously, we demonstrated an altered profile of LPA-dependent cAMP content during the aging process of human diploid fibroblasts (HDFs). In attempts to define the molecular events associated with the age-dependent changes in cAMP profiles, we determined the protein kinase A (PKA) activity, phosphorylation of cAMP-response element binding protein (CREB), and the protein expression of CRE-regulatory genes, c-fos and COX-2 in young and senescent HDFs. We observed in senescent cells, an increase in mRNA levels of the catalytic subunit a of PKA and of the major regulatory subunit Ialpha. Senescence-associated increase of cAMP after LPA treatment correlated well with increased CREB phosphorylation accompanying activation of PKA in senescent cells. In senescent cells, after LPA treatment, the expression of c-fos and COX-2 decreased initially, followed by an increase. In young HDFs, CREB phosphorylation decreased following LPA treatment, and both c-fos and COX-2 protein levels increased rapidly. CRE-luciferase assay revealed higher basal CRE-dependent gene expression in young HDFs compared to senescent HDFs. However, LPA-dependent slope of luciferase increased more rapidly in senescent cells than in young cells, presumably due to an increase of LPA-induced CREB phosphorylation. CRE-dependent luciferase activation was abrogated in the presence of inhibitors of PKC, MEK1, p38MAPK, and PKA, in both young and senescent HDFs. We conclude that these kinase are coactivators of the expression of CRE-responsive genes in LPA-induced HDFs and that their changed activities during the aging process contribute to the final expression level of CRE-responsive genes.     

Association between excision repair cross-complementation group 1 polymorphism and clinical outcome of platinum-based chemotherapy in patients with epithelial ovarian cancer

ERCC1 is a DNA repair gene and has been associated with resistance to DNA damaging agents. In this study we hypothesized that a polymorphism of ERCC1 Asn118Asn (C -> T) might affect the platinum-resistance of epithelial ovarian cancer patients to platinum-taxane chemotherapy administered postoperatively. Using the SNapShot assay, we assessed this polymorphism in ERCC1 in 60 ovarian cancer patients. Platinum-resistance was defined as progression on platinum-based chemotherapy or recurrence within 6 months of completing therapy. Although not significant, platinum-resistance was less frequently observed in patients with the C/T+T/T genotype (P=0.064). Multivariate analysis showed that the C/T+T/T genotypes constituted an independent predictive factor of reduced risk of platinum-resistance in ovarian cancer (odds ratio 0.17, 95% confidence interval 0.04-0.74, P=0.018, Fisher's exact test). No significant correlation was observed between overall survival and the ERCC1 polymorphism. Our results suggest that genotyping of the ERCC1 polymorphism Asn118Asn may be useful for predicting the platinum-resistance of epithelial ovarian cancer patients. However, these findings require prospective confirmation.     

Evidence of two-dimensional superconductivity in the single crystalline nanohybrid of organic-bismuth cuprate

A coordination compound of HgI(2)(pyridine)(2) can be successfully intercalated into a single crystalline Bi(2)Sr(2)CaCu(2)O(y) high-T(c) superconductor through an interlayer complexation reaction between pyridine molecules and bismuth cuprate pre-intercalated with mercuric iodide. X-ray diffraction and X-ray absorption spectroscopic results clearly demonstrate that the single crystalline nature of the pristine bismuth cuprate remains unchanged even after the intercalation of organic complex as well as those of iodine and mercuric iodide. According to the angle-dependent dc magnetization measurements, the intercalation of bulky organic molecules completely blocks superconductive currents along the c-axis, whereas a superconducting transition along the in-plane direction still occurs in the organic intercalate. In the case of the iodine or mercuric iodide intercalates with smaller lattice expansions, an out-of-plane diamagnetic transition is not wholly quenched but significantly depressed by the intercalation, confirming the reduction of interlayer interaction. The present finding can provide straightforward evidence of the two-dimensionality of high temperature superconductivity in the present cuprate-based nanohybrid material.     

Indium-mediated one-pot three-component reaction of aromatic amines, enol ethers, and allylic bromides

[reaction: see text] A new and efficient indium-mediated one-pot three-component reaction for the synthesis of N-aryl-substituted homoallylamines from aromatic amines, enol ethers, and allylic bromides in THF at room temperature is described.     

Generalized three-dimensional windowed Fourier transform for fringe analysis

A 3D windowed Fourier transform is proposed for fringe sequence analysis, which processes the joint spatial and temporal information of the fringe sequence simultaneously. The 2D windowed Fourier transform in the spatial domain and the 1D windowed Fourier transform in the temporal domain are two special cases of the proposed method. The principles of windowed Fourier filtering and windowed Fourier ridges are developed. Experimental verification shows encouraging results despite a longer processing time.     

Structures and properties of Newton black films characterized using molecular dynamics simulations

We used molecular dynamics (MD) simulations to investigate the structures and properties of Newton black films (NBF) for several surfactants: sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (C16TAB), and surfactin using film thicknesses up to 10 nm. By calculating the interface formation energy for various packing conditions on the surface pressure-area isotherm, we found that the most probable surface concentration is approximately 42 A(2)/molecule for SDS and C16TAB and approximately 170 A(2)/molecule for surfactin. We then used this most probable concentration of each surfactant to simulate NBF with various film thicknesses. From analyzing the disjoining pressure-film thickness isotherms with the density profiles and the solvation coordination number, we found that the increase of the disjoining pressure during the film thinning was coupled with the change in inner structure of the NBF (i.e., density profile and the solvation of ionic entities). In the range of film thicknesses less than approximately 30 A, the disjoining pressures for the SDS and C16TAB were found to be larger than that of the surfactin. We predicted the Gibbs elasticity (175 dyn/cm for surfactin; 109 dyn/cm for C16TAB; 38 dyn/cm for SDS) required to assess the stability of NBF against surface concentration fluctuations, and the shear modulus (6.5 GPa for the surfactin; 6.1 GPa for the C16TAB; 3.5 GPa for the SDS) and the yield stress (approximately 0.8 GPa for surfactin; approximately 0.8 GPa for C16TAB; approximately 0.4 GPa for the SDS) to assess the mechanical stability against the externally imposed mechanical perturbation.     

Synthesis and photovoltaic properties of a low‐band‐gap polymer consisting of alternating thiophene and benzothiadiazole derivatives for bulk‐heterojunction and dye‐sensitized solar cells

We synthesized a novel low‐band‐gap, conjugated polymer, poly[4,7‐bis(3′,3′‐diheptyl‐3,4‐propylenedioxythienyl)‐2,1,3‐benzothiadiazole] [poly(heptyl₄‐PTBT)], consisting of alternating electron‐rich, diheptyl‐substituted propylene dioxythiophene and electron‐deficient 2,1,3‐benzothiadiazole units, and its photovoltaic properties were investigated. A thin film of poly(heptyl₄‐PTBT) exhibited an optical band gap of 1.55 eV. A bulk‐heterojunction solar cell with indium tin oxide/poly(3,4‐ethylenedioxythiophene)/poly(heptyl₄‐PTBT): methanofullerene [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) (1:4)/LiF/Al was fabricated with poly(heptyl₄‐PTBT) as an electron donor and PCBM as an electron acceptor and showed an open‐circuit voltage, short‐circuit current density, and power conversion efficiency of 0.37 V, 3.15 mA/cm², and 0.35% under air mass 1.5 (AM1.5G) illumination (100 mW/cm²), respectively. A solid‐state, dye‐sensitized solar cell with a SnO₂:F/TiO₂/N3 dye/poly(heptyl₄‐PTBT)/Pt device was fabricated with poly(heptyl₄‐PTBT) as a hole‐transport material. This device exhibited a high power conversion efficiency of 3.1%, which is the highest power conversion efficiency value with hole‐transport materials in dye‐sensitized solar cells to date. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1394–1402, 2007     

Rh-catalyzed one-pot and practical transformation of aldoximes to amides

Wilkinson's complex has been found to catalyze the one-pot transformation of aldoximes to the corresponding amides with high selectivity and efficiency under essentially neutral conditions.     

Determination of the benzodiazepin-2-ones by circular dichroism

Formation constants for the 1:1 complexation equilibrium reactions between β-cyclodextrin and the drugs, clonazepam, delorazepam, diazepam (Valium), flurazepam (Dalmane), lorazepam, medazepam, nitrazepam, nordiazepam, oxazepam, and temazepam, were measured by using circular dichroism spectropolarimetry. The range in values is almost one order of magnitude, suggesting a strong structural dependence in the interlocking between the host and different guests. Enthalpy and entropy data for the lorazepam interaction are consistent with data from several earlier studies. Direct determinations of diazepam and flurazepamm in pharmaceutical products are within ±2% of the prescribed amounts.     

Separation of racemic 2,4-dinitrophenyl amino acids on 9-O-(phenyloxycarbonyl)quinine-bonded carbon-clad zirconia in reversed-phase liquid chromatography

Zirconia is known to be one of the best materials for the chromatographic support due to its excellent chemical, thermal, and mechanical stability. In this work, we report preparation and use of 9-O-(phenyloxycarbonyl)quinine-bonded carbon-clad zirconia (QNCZ) as a chiral stationary phase (CSP) for separation of N-(2,4-dinitrophenyl) (DNP)-amino acids (AAs) enantiomers in reversed-phase liquid chromatography. Retention and enantioselectivity of the QNCZ CSP were compared with those of quinine 3-triethoxysilylpropylcarbamate-coated zirconia (QNZ) and quinine 3-triethoxysilylpropylcarbamate-bonded silica (QNS). The QNCZ CSP showed in general the better enantioselectivity for most of the amino acids studied.