1,721,300 research outputs found
The RGM/DRAGON family of BMP co-receptors.
No full textThe BMP signaling pathway controls a number of cell processes during development and in adult tissues. At the cellular level, ligands of the BMP family act by binding a hetero-tetrameric signaling complex, composed of two type I and two type If receptors. BMP ligands make use of a limited number of receptors, which in turn activate a common signal transduction cascade at the intracellular level. A complex regulatory network is required in order to activate the signaling cascade at proper times and locations, and to generate specific downstream effects in the appropriate cellular context
Electrochemical and electrochromic properties of novel aromatic poly(amine-amide)s derived from N,N '-bis(4-carboxyphenyl)-N,N '-diphenyl-1,4-phenylenediamine
No full text[[abstract]]A series of novel triphenylamine-containing aromatic poly(amine-amide)s were prepared from the dicarboxylic acid, N,N'-bis(4-carboxyphenyl)-N,N'-diphetiyl-1,4-phenylenediamine, and various diamines by direct phosphorylation polycondensation. All the poly(amine-amide)s were amorphous, soluble in a variety of organic solvents, and could be solution cast into transparent, tough, and flexible films with good mechanical properties. They had useful levels of thermal stability associated with relatively high glass-transition temperatures (195-280 degrees C). These polymers exhibited strong UV-Vis absorption bands at 330-346 mn and their photoluminescence showed maximum bands around 516-535 nm in NMP solution. The hole-transporting and electrochromic properties are examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the poly(amine-amide)s prepared by casting polymer solution onto an indium-tin oxide (ITO)-coated glass substrate exhibited two reversible oxidative redox couples at potential 0.73-0.78 V and 1.12-1.18 V, respectively vs Ag/AgCl in acetonitrile solution. All the poly(amine-amide)s exhibited excellent reversibility of electrochromic characteristics by continuous ten cyclic scans between 0.0 and 1.40 V, with a color change from original pale yellowish neutral form to the green and then to blue oxidized forms. (C) 2005 Elsevier Ltd. All rights reserved.[[note]]SC
Species composition and structure of a montane rainforest of Mt. Lopei in northern Taiwan.
No full textIs STAT3 and PTEN expression altered in canine prostate cancer?
No full textSignal transducer and activator of transcription 3 (STAT3) and phosphatase and tensin homologue (PTEN) are, respectively, an oncogene and tumour suppressor gene whose dysregulated expression in human prostate cancer is associated with increased malignancy and poor prognosis. Both markers were evaluated in 12 samples of canine benign prostatic hyperplasia (BPH) and 17 canine prostatic carcinomas (PCs) by immunohistochemistry, to understand their possible role in canine prostate carcinogenesis. STAT3 was expressed in 25% and 82.35% of BPH and PC, respectively, with a significantly higher number of STAT3-positive cells in malignant compared with hyperplastic lesions. Three PCs had occasional nuclear expression of STAT3. PTEN was expressed in BPH and PC with a similar distribution and percentage of positive cells; however, four PCs were PTEN negative. Solid PCs contained more STAT3-positive and fewer PTEN-positive cells compared with the other subtypes. A reduced number of PTEN-positive cells was observed in PCs with a high Gleason score (GS10), while no association was demonstrated between STAT3 expression and Gleason score. The data suggest that overexpression of STAT3 and downregulation of PTEN may be an important step in canine prostate carcinogenesis and both markers may be related to the histological subtypes of PC and the degree of differentiation of neoplastic cells
Mesoporous TiO2/SBA-15, and Cu/TiO2/SBA-15 Composite Photocatalysts for Photoreduction of CO2 to Methanol
No full textSynthesis and Electrochemical Properties of Novel Aromatic Poly(amine-amide)s with Anodically Highly Stable Yellow and Blue Electrochromic Behaviors
No full text[[abstract]]A new triphenylamine-containing aromatic diamine, 4,4'-bis[4-aminophenyl(4-methoxyphenyl)]-4 ''-methoxytriphenylamine (5), was Successfully synthesized by the Ullmann reaction of 4,4'-dibromo-4 ''-methoxytriphenylamine (2) with 4-methoxy-4 ''-nitrodiphenylamine (3), followed by palladium-catalyzed hydrazine reduction of the dinitro (4) intermediate. A series of novel polyamides having inherent viscosities of 0.22-0.64 dL/g were prepared via the direct phosphorylation polycondensation from the diamine and various dicarboxylic acids. All the polymers were amorphous with good solubility in many organic solvents, Such as N-methyl-2-pyrrolidinone (NMP) and N,N-dimethylacetamide (DMAc), and Could be solution-cast into polymer films. These aromatic polyamides had useful levels of thermal stability associated with their relatively high softening temperature (200-244 degrees C), 10% weight-loss temperatures in excess of 460 degrees C, and char yields at 800 degrees C in nitrogen higher than 55%. The hole-transporting and electrochromic properties are examined by electrochemical and spectroelectrochemical methods. Oxidation of compound 4 was proved by using an optically transparent thin-layer electrode (OTTLE) cell Coupled with UV-vis/NIR spectroscopy. Reversibility of the first oxidation was up to 99%, second oxidation was 94%, and third oxidation was 80%. Polyamide Ic shows the reversibility of the first oxidation was Lip to 100%, second oxidation was 99%, and third oxidation was 75%. Cyclic voltammograms of the polyamide films cast onto an indium-fin oxide (ITO)-coated glass substrate exhibited three reversible oxidation redox couples (E(1/2)) at 0.39-0.47, 0.64-0.72, and 1.02-1.13 V vs Ag/AgCI in acetonitrile solution, and polyamide Ie showed additional fourth reversible oxidation redox Couples at 1.07 V. The polyamide films revealed excellent reversible stability of anodic electrochromic characteristics with a color change from the colorless or pale yellowish neutral form to yellow and blue oxidized form at applied potentials ranging from 0.00 to 0.80 V. These electrochromic materials not only showed good coloration efficiency of yellow (CE = 203 cm(2)/C) and blue (CE = 194 cm(2)/C) but also exhibited high contrast of optical transmittance change (Delta T %) Lip to 59% at 443 nm for yellow and 79% at 1080 nm for blue. After over 500 cyclic switches, the polymer films still exhibited excellent stability of electrochromic characteristics.[[note]]SC
Lysophosphatidic acid induced oxidized LDL uptake is class A scavenger receptor dependent in mouse macrophages.
No full textPoly(triphenylamine)s Derived from Oxidative Coupling Reaction: Substituent Effects on the Polymerization, Electrochemical, and Electro-Optical Properties
No full text[[abstract]]A series of triphenylamine-based polymers containing electron-donating methoxy (-OCH(3)) and electron-withdrawing cyano or nitro (-CN or -NO(2)) substituents in the main chains have been designed and investigated. These conjugated polymers (P1-P3) could be readily prepared by oxidative coupling polymerization from monomers (M1-M3) using FeCl(3) as an oxidant. The P2 and P3 exhibited moderate high T(g) values (203-205 degrees C) and thermal stability. These polymers in NMP solution showed UV-vis absorption around 288-404 nm and photoluminescence peaks around 435-492 nm. P1-P3 showed reversible oxidation redox couples at E(onset) = 0.67, 0.99, and 1.00 V in solution of 0.1 M tetrabutylammonium perchlorate (TBAP)/acetonitrile (CH(3)CN), respectively. M3 and P3 exhibited reversible reduction redox couples at E(onset) = -1.04 and -1.03 V. These polymers also revealed electrochromic characteristic changing color at different potential. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 285-294, 2009[[note]]SC
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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