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41.
Alapafuja SO Nikas SP Shukla VG Papanastasiou I Makriyannis A 《Tetrahedron letters》2009,50(50):7028-5332
We describe the use of a microwave reaction for the conversion of various bromides to sodium sulfonates that have been further elaborated to sulfonyl chlorides. This new approach leads to much improved yields and shorter reaction times. Representative sulfonyl chlorides serve as precursors for the respective sulfonyl fluorides that are potent inhibitors of the fatty acid amide hydrolase. 相似文献
42.
Alexandros G. Koutsioubas Nikolaos Spiliopoulos Dimitrios L. Anastassopoulos Alexandros A. Vradis George D. Priftis 《Journal of Polymer Science.Polymer Physics》2007,45(15):2060-2070
The potential application of Surface Plasmon Resonance (SPR) spectroscopy in evaluating the thickness and volume fraction of adsorbed macromolecular layers is discussed in this work. The sensitivity of SPR spectroscopy to different layer concentration and to the layer extension normal to the surface (thickness) is theoretically illustrated. A new approach for the interpretation of SPR data is presented, which is applicable whenever the functional form of the density profile is known. The use of the proposed procedure for the fitting of experimental results from PS‐PEO brush self‐assembly on alumina surface has allowed the determination of the layer parameters, which have been found to be in accordance with theoretical mean‐field and scaling predictions, being also in good agreement with previous results from neutron reflectivity experiments. Furthermore, it has been confirmed that the dependence of the brush layer thickness d on the molecular weight Mw obeys the scaling law d ~ Mw0.63. Since surface plasmon measurements can be acquired quite fast, it is suggested that under the present analysis scheme, the technique may be implemented to probe the average conformational properties of adsorbed macromolecular layers during their formation or under external stimuli. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2060–2070, 2007 相似文献
43.
Alexandros Perivolaris Athena M. Fidelli Ross Inglis Vadim G. Kessler Alexandra M.Z. Slawin 《Journal of Coordination Chemistry》2014,67(23-24):3972-3986
In an attempt to employ salicylic acid (HOsalH), 2,6-dihydroxy benzoic acid {(HO)2PhCO2H}, and naphthalene-1,8-dicarboxylic acid {1,8-naph(CO2H)2} in Mn(III) salicylaldoximate chemistry as a means to alter the structural identity of the hexanucluear clusters usually obtained from this reaction system, we have isolated a family of hexanuclear Mn(III) complexes based on salicyladloxime (saoH2) and 2-hydroxy-1-naphthaldehyde oxime (naphthsaoH2). Five hexanuclear clusters, [Mn6O2(sao)6(HOsal)2(EtOH)4]·EtOH (1·EtOH), [Mn6O2(sao)6{1,8-naph(CO2Me)(CO2)}2(MeOH)6]·3MeOH (2·3MeOH), [Mn6O2(naphthsao)6{1,8-naph(CO2Et)(CO2)}2(EtOH)6] (3·2MeOH), [Mn6O2(naphthsao)6(MeCO2)2(EtOH)4]·2H2O (4·2H2O), and [Mn6O2(naphthsao)6{(HO)2PhCO2}2(EtOH)4]·4EtOH (5·4EtOH), have been synthesized and characterized by single-crystal X-ray crystallography. The magnetic properties of 3, 4, and 5 are discussed. 相似文献
44.
Niki Mavragani Dr. Alexandros A. Kitos Prof. Jaclyn L. Brusso Prof. Muralee Murugesu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(16):5091-5106
Although 1,2,4,5-tetrazines or s-tetrazines have been known in the literature for more than a century, their coordination chemistry has become increasingly popular in recent years due to their unique redox activity, multiple binding sites and their various applications. The electron-poor character of the ring and stabilization of the radical anion through all four nitrogen atoms in their metal complexes provide new aspects in molecular magnetism towards the synthesis of new high performing Single Molecule Magnets (SMMs). The scope of this review is to examine the role of s-tetrazine radical ligands in transition metal and lanthanide based SMMs and provide a critical overview of the progress thus far in this field. As well, general synthetic routes and new insights for the preparation of s-tetrazines are discussed, along with their redox activity and applications in various fields. Concluding remarks along with the limitations and perspectives of these ligands are discussed. 相似文献
45.
A numerical method is developed for the dynamic analysis of ring-stiffened circular cylindrical thin elastic shells. Only circular symmetric vibrations of the shell segments and radial and torsional vibrations of the rings are considered. The geometric and material properties of the shell segments and the rings may vary from segment to segment. Free vibrations or forced vibrations due to harmonic pressure loading are treated with the aid of dynamic stiffness influence coefficients for shell segments and rings. Forced vibrations due to transient pressure loading are treated with the aid of dynamic stiffness influence coefficients for shell segments and rings defined in the Laplace transform domain. The time domain response is then obtained by a numerical inversion of the transformed solution. The effect of external viscous or internal viscoelastic damping is also investigated by the proposed method. In all the cases, the dynamic problem is reduced to a static-like form and the “exact” solution of the problem is numerically obtained. 相似文献
46.
Alexandros Pitilakis Odysseas Tsilipakos Emmanouil E. Kriezis 《Applied Physics A: Materials Science & Processing》2014,115(2):475-479
Hybrid silicon-plasmonic waveguides constitute an appealing platform for integrated photonic circuitry. They merge the technical maturity and prevalence of the SOI platform with the subwavelength confinement of plasmonic waveguides, essential for accessing enhanced nonlinear response at micron length-scales. Employing full-wave numerical simulations complemented with Schrödinger equation techniques, we propose nonlinear waveguide designs for Kerr-effect applications exhibiting minimized impairments due to free-carrier effects, thus raising the power-ceiling imposed on standard silicon waveguides. 相似文献
47.
Demetris P. Papahatjis Dr. Victoria R. Nahmias Spyros P. Nikas Dr. Marion Schimpgen Alexandros Makriyannis 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(13):4091-4099
Two novel methyl‐substituted arachidonic acid derivatives were prepared in an enantioselective manner from commercially available chiral building blocks, and were found to be excellent templates for the development of (13S)‐methyl‐substituted anandamide analogues. One of the compounds synthesized, namely, (13S,5Z,8Z,11Z,14Z)‐13‐methyl‐eicosa‐5,8,11,14‐tetraenoic acid N‐(2‐hydroxyethyl)amide, is an endocannabinoid analogue with remarkably high affinity for the CB1 cannabinoid receptor. 相似文献
48.
49.
Godlewski G Alapafuja SO Bátkai S Nikas SP Cinar R Offertáler L Osei-Hyiaman D Liu J Mukhopadhyay B Harvey-White J Tam J Pacak K Blankman JL Cravatt BF Makriyannis A Kunos G 《Chemistry & biology》2010,17(11):1256-1266
The enzyme fatty acid amide hydrolase (FAAH) catalyzes the in vivo degradation of the endocannabinoid anandamide, thus controlling its action at receptors. A novel FAAH inhibitor, AM3506, normalizes the elevated blood pressure and cardiac contractility of spontaneously hypertensive rats (SHR) without affecting these parameters in normotensive rats. These effects are due to blockade of FAAH and a corresponding rise in brain anandamide levels, resulting in CB? receptor-mediated decrease in sympathetic tone. The supersensitivity of SHR to CB? receptor-mediated cardiovascular depression is related to increased G protein coupling of CB? receptors. Importantly, AM3506 does not elicit hyperglycemia and insulin resistance seen with other FAAH inhibitors or in FAAH?/? mice, which is related to its inability to inhibit FAAH in the liver due to rapid hepatic uptake and metabolism. This unique activity profile offers improved therapeutic value in hypertension. 相似文献
50.
Constantine D. Stalikas Alexandros Ch. Pappas Miltiades I. Karayannis Panayotis G. Veltsistas 《Mikrochimica acta》2003,142(1-2):43-48
Squaric acid (1,2-dihydroxy-3,4-diketo-cyclobutene) is used in a specific reaction with Fe(III) for the spectrophotometric
determination of Fe(III) and total iron content. The optimization of the experimental parameters leads to the establishment
of a simple, fast and accurate analytical method. The analytical procedure includes mixing ammonium squarate (40 mM), prepared
in a phthalate buffer solution of pH 2.7, with the sample and measuring the absorbance at 515 nm. The molar absorptivity of
the colored product is 3.95×103 L·mol−1·cm−1, at 515 nm. Calibration graphs for Fe(III) are rectilinear for 0.5–20 mgL−1, with a detection limit of 0.3 mgL−1 and r.s.d. not exceeding 2.5%, for five replicates of a 3.0 mgL−1 standard solution. The method has been successfully applied to the determination of iron (III) and the total iron content
after quantitative oxidation of iron (II). The results for several analyzed samples when compared with those acquired by using
the FAAS technique, were found to be in satisfactory agreement.
Author for correspondence: University of Ioannina, Department of Chemistry, Laboratory of Analytical Chemistry, Ioannina 451
10, Greece. E-mail: panavelt@cc.uoi.gr
Received July 27, 2002; accepted December 20, 2002
Published online April 11, 2003 相似文献