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1.
Sauaia MG de Lima RG Tedesco AC da Silva RS 《Journal of the American Chemical Society》2003,125(48):14718-14719
The binuclear complex [RuII(NH3)5(pz)RuII(bpy)2(NO)](PF6)5 was prepared and characterized by elemental analysis, UV-vis, and IR spectroscopy. The complex UV-vis spectrum has presented bands at 242, 286, and 530 nm in acetate buffer solution at pH 4.5. The photochemical study by laser flash-photolysis at 532 nm showed the NO release account from the NO measured by a NO sensor. The quantum yield for NO release (0.025 +/- 0.004 mol einsten-1) was determined with a laser flash-photolysis apparatus (Continuum Q-switched Nd:YAG laser). The major irradiation product of the [RuII(NH3)5(pz)RuII(bpy)2(NO)]5+ complex besides nitric oxide is [RuIII(NH3)5(pz)RuII(bpy)2(H2O)]5+. 相似文献
2.
Sanchez-sanz M; Blyth MG 《The Quarterly Journal of Mechanics and Applied Mathematics》2007,60(2):125-138
Unsteady, axisymmetric stagnation flow about a circular cylinderis examined when the far-field flow is a periodic function oftime with a fixed time average and an oscillatory part of prescribedamplitude and frequency. Solutions are computed for arbitraryvalues of the Reynolds number, quantifying the effects of surfacecurvature, and a frequency parameter based on the period ofthe far-field flow. It is found that solutions remain regularand periodic provided that the far-field amplitude lies belowa critical value. Above this value, solutions terminate in afinite-time singularity. The blow-up time is delayed by increasingthe curvature of the surface. These results are corroboratedby asymptotic predictions valid in the limits of small and largeamplitude and frequency. For large Reynolds number, the problemreduces to the two-dimensional stagnation-point flow againsta plane wall studied by previous authors. 相似文献
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S -nitrosothiols have many biological activities and may act as nitric oxide (NO) carriers and donors, prolonging NO half-life in vivo. In spite of their great potential as therapeutic agents, most S -nitrosothiols are too unstable to isolate. We have shown that the S -nitroso adduct of N -acetylcysteine (SNAC) can be synthesized directly in aqueous and polyethylene glycol (PEG) 400 matrix by using a reactive gaseous (NO/O2 ) mixture. Spectral monitoring of the S–N bond cleavage showed that SNAC, synthesized by this method, is relatively stable in nonbuf-fered aqueous solution at 25°C in the dark and that its stability is greatly increased in PEG matrix, resulting in a 28-fold decrease in its initial rate of thermal decomposition. Irradiation with UV light (λ= 333 nm) accelerated the rate of decomposition of SNAC to NO in both matrices, indicating that SNAC may find use for the photogeneration of NO. The quantum yield for SNAC decomposition decreased from 0.65 ± 0.15 in aqueous solution to 0.047 ± 0.005 in PEG 400 matrix. This increased stability in PEG matrix was assigned to a cage effect promoted by the PEG microenvironment that increases the rate of geminated radical pair recombination in the homolytic S–N bond cleavage process. This effect allowed for the storage of SNAC in PEG at −20°C in the dark for more than 10 weeks with negligible decomposition. Such stabilization may represent a viable option for the synthesis, storage and handling of S -nitrosothiol solutions for biomedical applications. 相似文献
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Renata Galvão de Lima Marilia Gama Sauaia Camila Ferezin Iuri Muniz Pepe Nádia Mamede José Lusiane M. Bendhack Zênis Novais da Rocha Roberto Santana da Silva 《Polyhedron》2007
The entrapped [Ru(terpy)(L)NO](PF6)3, where terpy = 2,2′:6′,2″-terpyridine and L = 2,2′-bipyridine (bpy) and 3,4-diiminebenzoic acid (NH · NHq) complexes into sol–gel processed polysiloxane and silicone matrices, shows NO release characteristics when submitted to light irradiation at 355 and 532 nm, as judged by NO measurement using a NO-sensor electrode. The pharmacological properties of doped matrix showed vasodilator characteristics by visible light irradiation, which is of great interest because the target delivery system can avoid the occurrence of side effects possibly by the aquo ruthenium species. All matrices obtained showed to be amorphous materials. The scanning electron micrographs of the matrices showed irregularly shaped particles, with a broad size of 1000 μm for both matrices and homogeneous distribution. 相似文献
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马丽娜 《纯粹数学与应用数学》2007,23(4):549-555
通过构造两个非负鞅证明了一个强极限定理,然后把它应用到本文所定义的广义Bethe树上的奇偶马尔可夫链场上,从而获得了此马氏链场上的一类强极限定理. 相似文献
7.
A series of cis nitrosyl complexes containing polypyridyl ligands were prepared and characterized as cis-[RuL(bpy)2(NO)](PF6)3 (L = pyridine, 4-picoline, or 4-acetylpyridine), by elemental analysis, u.v.–vis. and i.r. spectroscopy, and by electrochemical techniques such as cyclic voltammetry, differential pulse voltammetry, spectroelectrochemistry, and coulometry. The complexes exhibit stretching frequencies (NO) at ca. 1950 cm–1 indicating that nitrosyl group has a sufficiently high degree of nitrosonium ion (NO+) character. In non-aqueous solution, the reduction of these complexes induce nitrosyl to nitro conversion. In aqueous solution the reduction product is cis-[RuL(bpy)2(NH3)]2+ formed by a six electron mechanism. The nitrosyl compounds are susceptible to nucleophilic attack by hydroxide ion. The equilibrium constants were determined. 相似文献
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Conway GD Borba DN Alper B Bartlett DV Gormezano C von Hellermann MG Maas AC Parail VV Smeulders P Zastrow KD 《Physical review letters》2000,84(7):1463-1466
Correlation of density turbulence suppression and reduced plasma transport is observed in the internal transport barrier (ITB) region of JET tokamak discharges with optimized magnetic shear. The suppression occurs in two stages. First, low frequency turbulence and ion transport are reduced across the plasma core by a toroidal velocity shear generated by intense auxiliary heating. Then with the ITB formation, high frequency turbulence and electron transport are reduced locally within the steep pressure gradient region of the ITB. 相似文献
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[Ru(II)L(NH(3))(4)(pz)Ru(II)(bpy)(2)(NO)](PF(6))(5) (L is NH(3), py, or 4-acpy) was prepared with good yields in a straightforward way by mixing an equimolar ratio of cis-[Ru(NO(2))(bpy)(2)(NO)](PF(6))(2), sodium azide (NaN(3)), and trans-[RuL(NH(3))(4)(pz)] (PF(6))(2) in acetone. These binuclear compounds display nu(NO) at ca. 1945 cm(-)(1), indicating that the nitrosyl group exhibits a sufficiently high degree of nitrosonium ion (NO(+)). The electronic spectrum of the [Ru(II)L(NH(3))(4)(pz)Ru(II)(bpy)(2)(NO)](5+) complex in aqueous solution displays the bands in the ultraviolet and visible regions typical of intraligand and metal-to-ligand charge transfers, respectively. Cyclic voltammograms of the binuclear complexes in acetonitrile give evidence of three one-electron redox processes consisting of one oxidation due to the Ru(2+/3+) redox couple and two reductions concerning the nitrosyl ligand. Flash photolysis of the [Ru(II)L(NH(3))(4)(pz)Ru(II)(bpy)(2)(NO)](5+) complex is capable of releasing nitric oxide (NO) upon irradiation at 355 and 532 nm. NO production was detected and quantified by an amperometric technique with a selective electrode (NOmeter). The irradiation at 532 nm leads to NO release as a consequence of a photoinduced electron transfer. All species exhibit similar photochemical behavior, a feature that makes their study extremely important for their future application in the upgrade of photodynamic therapy in living organisms. 相似文献
10.
A De A Mitra A Ray SR Banerjee M Sengupta A Chatterjee S Kailas HS Patel MG Betigiri SK Dutta 《Pramana》1999,53(3):549-552
In this paper, we report our measurements of back-angle oxygen and carbon particle yields from 16O+89Y, 12C+93Nb reactions forming the same compound nucleus 105Ag at the same excitation energy and spin distribution. We find anomalously large oxygen yield and entrance channel dependence
at high excitation energies from 16O+89Y reaction implying formation of a dinuclear orbiting complex. Possible connection between nuclear orbiting and fast fission
is also discussed. 相似文献