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461.
Radosław Kotuniak Marc J. F. Strampraad Karolina Bossak-Ahmad Dr. Urszula E. Wawrzyniak Iwona Ufnalska Dr. Peter-Leon Hagedoorn Prof. Wojciech Bal 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(28):11330-11335
The amino-terminal copper and nickel/N-terminal site (ATCUN/NTS) present in proteins and bioactive peptides exhibits high affinity towards CuII ions and have been implicated in human copper physiology. Little is known, however, about the rate and exact mechanism of formation of such complexes. We used the stopped-flow and microsecond freeze-hyperquenching (MHQ) techniques supported by steady-state spectroscopic and electrochemical data to demonstrate the formation of partially coordinated intermediate CuII complexes formed by glycyl–glycyl–histidine (GGH) peptide, the simplest ATCUN/NTS model. One of these novel intermediates, characterized by two-nitrogen coordination, t1/2≈100 ms at pH 6.0 and the ability to maintain the CuII/CuI redox pair is the best candidate for the long-sought reactive species in extracellular copper transport. 相似文献
462.
Iwona Skrzypczak 《NoDEA : Nonlinear Differential Equations and Applications》2014,21(6):841-868
We derive Hardy inequalities in weighted Sobolev spaces via anticoercive partial differential inequalities of elliptic type involving A-Laplacian ?Δ A u = ?divA(?u) ≥ Φ, where Φ is a given locally integrable function and u is defined on an open subset \({\Omega \subseteq \mathbb{R}^n}\) . Knowing solutions we derive Caccioppoli inequalities for u. As a consequence we obtain Hardy inequalities for compactly supported Lipschitz functions involving certain measures, having the form $$\int_\Omega F_{\bar{A}}(|\xi|) \mu_1(dx) \leq \int_\Omega \bar{A}(|\nabla \xi|)\mu_2(dx),$$ where \({\bar{A}(t)}\) is a Young function related to A and satisfying Δ′-condition, while \({F_{\bar{A}}(t) = 1/(\bar{A}(1/t))}\) . Examples involving \({\bar{A}(t) = t^p{\rm log}^\alpha(2+t), p \geq 1, \alpha \geq 0}\) are given. The work extends our previous work (Skrzypczaki, in Nonlinear Anal TMA 93:30–50, 2013), where we dealt with inequality ?Δ p u ≥ Φ, leading to Hardy and Hardy–Poincaré inequalities with the best constants. 相似文献
463.
Łakomska I Fandzloch M Wojtczak A Szłyk E 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(3):497-501
Novel platinum(IV) coordination compounds with 5-methyl-1,2,4-triazolo[1,5-a]pyrimidin-7(4H)-one (HmtpO): cis-trans-[PtCl(2)(OH)(2)(NH(3))(HmtpO)] (1), cis-trans-[PtCl(5)(HmtpO)][(CH(3))(2)NH(2)] (2) have been prepared and structurally characterized by spectroscopic methods ((1)H, IR and X-ray crystallography (2)). The X-ray results indicate that the local geometry around the platinum(IV) centre approximates a typical octahedral arrangement with nitrogen atom N3 of the HmtpO and three chloride atoms in equatorial positions. The remaining two axial positions are occupied by two chlorides. The preliminary assessment of antitumor properties of (1) was performed as an in vitro antiproliferative activity against HL-60 human acute promyelocytic leukemia and HCV29T bladder cancer. The cis-trans-[PtCl(2)(OH)(2)(NH(3))(HmtpO)] (1) exhibits higher cytotoxic activity against HL-60 (IC(50)=6.4 μM) than cisplatin. 相似文献
464.
Lewiński J Kaczorowski T Justyniak I Prochowicz D 《Chemical communications (Cambridge, England)》2011,47(3):950-952
The bimetallic chiral bipyridyl-type metalloligands based on aluminium derivatives of cinchonine, [R(2)Al(μ-CN)](2) (R = Me or Et), in combination with the corresponding ZnR(2) compound as nodes were used for the generation of novel homochiral heterometallic coordination polymers of either zig-zag or helical topology, depending on the character of the R substituent. 相似文献
465.
Bury W Krajewska E Dutkiewicz M Sokołowski K Justyniak I Kaszkur Z Kurzydłowski KJ Płociński T Lewiński J 《Chemical communications (Cambridge, England)》2011,47(19):5467-5469
The reaction of (t)Bu(2)Zn with water was investigated which led to isolation of the novel hexameric tert-butylzinc hydroxide. The resulting zinc hydroxide cluster appears to be an ideal predesigned single-source precursor which decomposes smoothly in one step at only ca. 120 °C into ZnO nanoparticles. 相似文献
466.
Dariusz Wyrzykowski Iwona Inkielewicz‐Stępniak Justyna Czupryniak Dagmara Jacewicz Tadeusz Ossowski Michal Woźniak Lech Chmurzyński 《无机化学与普通化学杂志》2013,639(10):1795-1799
The reactivity of superoxide free radicals (O2 · –) generated electrochemically towards the oxydiacetate metal complexes, namely [VO(oda)(H2O)2], [Co(oda)(H2O)2] · H2O, and [Ni(oda)(H2O)3] · 1.5H2O (oda = oxydiacetate) was examined by cyclic voltammetry. The measurements were carried out in DMSO solution using a platinum electrode. Based on the height of the anodic peak Ea that corresponds to electrochemical oxidation O2 · – → O2 + e, in the absence and in the presence of the compounds in the mixture, their O2 · – scavenge ability was assessed. The influence of the type of the complex was briefly discussed. H2O2 was used to induce cellular injury in a mouse hippocampal cell line (HT22). The cytoprotection of chemical compounds was tested at the mitochondrial (MTT test) and plasma membrane level (LDH leakage). Dose‐dependent effect (10 and 100 μM of the complex) of investigated compounds was observed. 相似文献
467.
Agata Jargiło Iwona Grabowska Hanna Radecka Magdalena Sulima Ilona Marszałek Aleksandra Wysłouch‐Cieszyńska Wim Dehaen Jerzy Radecki 《Electroanalysis》2013,25(5):1185-1193
The new system which consists of the thiol derivative of dipyrromethene–Cu(II) complex created on the surface of a gold electrode was applied for the first time for oriented immobilization of selected His‐tagged domains of a receptor for advanced glycation endproducts (RAGE). Cyclic voltammetry (CV), Osteryoung square‐wave voltammetry (OSWV), electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM) were used for characterization of the redox active sensing layer. The biosensor proposed was applied for determination of Aβ16–23′ peptide. In its presence, a decrease of the maximum Cu(II) redox current was observed. These values correlated linearly with the Aβ16–23′ concentration in the range 0.001–1.000 µM. The presence of diluted human plasma has no influence on the sensor responses. 相似文献
468.
Iwona Dams Michał Chodyński Małgorzata Krupa Anita Pietraszek Marta Zezula Piotr Cmoch Monika Kosińska Andrzej Kutner 《Tetrahedron》2013,69(5):1634-1648
The 16-(3-trifluoromethyl)phenoxy PGF2α analogue travoprost (8a) has potent topical ocular activity. A novel convergent synthesis of 13,14-en-15-ol PGF2α analogues was developed employing Julia–Lythgoe olefination of the structurally advanced prostaglandin phenylsulfone (5Z)-(+)-15 with a new enantiomerically pure aldehyde ω-chain synthon (S)-(?)-16a. Subsequent hydrolysis of protecting groups and final esterification of fluprostenol (7a) yielded travoprost (8a). The main advantages are the preparation of high purity travoprost (8a) and the application of comparatively cheap reagents. The novel convergent strategy allows the synthesis of a whole series of 13,14-en-15-ol PGF2α analogues from a common and structurally advanced prostaglandin intermediate 15. The preparation and identification of two synthetic impurities, 15-epi isomer (8b) of travoprost and a new prostaglandin related ester (5Z)-(+)-18, are also described. 相似文献
469.
Małecka J Lewandowska U Kamiński R Mames I Więckowska A Bilewicz R Korybut-Daszkiewicz B Woźniak K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(44):12385-12395
Multicenter (bi-, tri-, and tetranuclear) tetraazamacrocyclic complexes were self-assembled from Ni and Cu tetraazamacrocyclic mononuclear units and α,ω-diamines as building blocks. The structures of all compounds studied were proved by spectroscopic methods (ESI MS and NMR spectroscopy). Electrochemical experiments revealed reversible one-electron electrode processes at each of the Ni(2+) and Cu(2+) centers with formation of metal cations in oxidation state +3. Long linkers allow bi- and trinuclear complexes with noninteracting metal centers to be obtained. In the case of the short linkers (e.g. ethylenediamine) higher, trinuclear species are formed as major product. The structures of the bis- and tris-macrocyclic systems were confirmed by single-crystal X-ray diffraction. The tris-macrocyclic systems form cations in the shape of triangles partially filled with counterions and solvent molecules. The cations form positively charged layers, which interact in the crystal lattice with the neighboring negatively charged layers of anions. In solution, the trinuclear complexes exhibit strong host-guest interactions with 9,10-dimethyltriptycene due to complementarity of shape and size of this guest molecule. The association constants were determined by NMR spectroscopy and voltammetry, and very good agreement was obtained. The structural flexibility of the tetranuclear complex with long linkers allows for attractive interactions between the metal-complexing macrocycles that result in folding of the molecule. On the contrary, no folding is possible in the case of short linkers consisting of two CH(2) groups. 相似文献
470.
Double Deposition and Stripping Steps for Trace Determination of Au(III) Using Anodic Stripping Voltammetry 下载免费PDF全文
A new way of decreasing the detection limit ‐ double deposition and stripping steps was proposed to determine trace amounts of gold(III) by anodic stripping voltammetry. Two carbon composite electrodes that differed drastically in their surface areas were used for the measurements. The calibration graph was linear from 1×10?9 to 1×10?8 mol L?1 following deposition time of 300 s at the first and the second electrode. The detection limit was found to be 2.3×10?10 and 1.4×10?11 mol L?1 for deposition time 600 and 2400 s, respectively. It is the lowest detection limit obtained so far for gold(III) determination in stripping voltammetry. 相似文献