다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

For economical and ecological reasons, synthetic chemists are confronted with the increasing obligation of optimizing their synthetic methods. Maximizing efficiency and minimizing costs in the production of molecules and macromolecules constitutes, therefore, one of the most exciting challenges of synthetic chemistry.1-3 The ideal synthesis should produce the desired product in 100% yield and selectivity, in a safe and environmentally acceptable process.4 It is now well recognized that organometallic homogeneous catalysis offers one of the most promising approaches for solving this basic problem.2 Indeed, many of these homogeneous processes occur in high yields and selectivities and under mild reaction conditions. Most importantly, the steric and electronic properties of these catalysts can be tuned by varying the metal center and/or the ligands, thus rendering tailor-made molecular and macromolecular structures accessible.5,6 Despite the fact that various efficient methods, based on organometallic homogeneous catalysis, have been developed over the last 30 years on the laboratory scale, the industrial use of homogeneous catalytic processes is relatively limited.7 The separation of the products from the reaction mixture, the recovery of the catalysts, and the need for organic solvents are the major disadvantages in the homogeneous catalytic process. For these reasons, many homogeneous processes are not used on an industrial scale despite their benefits. Among the various approaches to address these problems, liquidliquid biphasic catalysis (“biphasic catalysis”) has emerged as one of the most important alternatives.6-11 The concept of this system implies that the molecular catalyst is soluble in only one phase whereas the substrates/products remain in the other phase. The reaction can take place in one (or both) of the phases or at the interface. In most cases, the catalyst phase can be reused and the products/substrates are simply removed from the reaction mixture by decantation. Moreover, in these biphasic systems it is possible to extract the primary products during the reaction and thus modulate the product selectivity.12 For a detailed discussion about this and other concepts of homogeneous catalyst immobilization, the reader is referred elsewhere.6,7 These biphasic systems might combine the advantages of both homogeneous (greater catalyst efficiency and mild reaction conditions) and heterogeneous (ease of catalyst recycling and separation of the products) catalysis. The advent of water-soluble organometallic complexes, especially those based on sulfonated phosphorus-containing ligands, has enabled various biphasic catalytic reactions to be conducted on an industrial scale.13-15 However, the use of water as a * Corresponding author. Fax: ++ 55 51 3316 73 04. E-mail: dupont@iq.ufrgs.br. 3667 Chem. Rev. 2002, 102, 3667−3692

https://www.chem.ccu.edu.tw/~joyce/referance/gump/IL/Chem.%20Rev.%202002,%20102,%203667.pdf

Ionic liquid (molten salt) phase organometallic catalysis.

Rate constants have been compiled for reactions of various inorganic radicals produced by radiolysis or photolysis, as well as by other chemical means in aqueous solutions. Data are included for the reactions of ⋅CO2 −, ⋅CO3⋅−, O3, ⋅N3, ⋅NH2, ⋅NO2, NO3⋅, ⋅PO32−, PO4⋅2−, SO2⋅ −, ⋅SO3 −, SO4⋅−, ⋅SO5⋅−, ⋅SeO3⋅ −, ⋅(SCN)2⋅ −, ⋅CL2⋅−, ⋅Br2⋅ −, ⋅I2⋅ −, ⋅ClO2⋅, ⋅BrO2⋅, and miscellaneous related radicals, with inorganic and organic compounds.

Rate Constants for Reactions of Inorganic Radicals in Aqueous Solution

Singular Integral Equations. By N.I. Muskhelishvili. Translated fromthe 2nd Russian edition by J.R.M. Radok. Pp. 447. F1. 28.50. 1953. (Noordhoff, Groningen)

Ionic liquids are liquids composed completely of ions. In the past two decades, ionic liquids have been widely used as “green solvents” replacing traditional organic solvents for organic synthesis and catalysis. In addition, ionic liquids are playing an increasingly important role in separation science. In this Account, the application of ionic liquids in all areas of separation science including extractions, gas chromatography, and supported liquid membrane processes are highlighted.

Ionic liquids in separations.

Solute‐solute interactions in aqueous solutions of nonelectrolytes are interpreted using both lattice and distribution function theories of the dissolved state. Experimental activity data of high precision can be obtained from the literature for aqueous solutions of many nonelectrolytes. If the logarithm of the solvent activity coefficient (γ1) is expressed as a power series in the mole fraction of the solute (x2), lnγ1 = Bx22 + Cx23 + ···, then the coefficients B and C can be determined analytically from the experimental measurements. Values of B were obtained for 52 aqueous mixtures; values of C were obtained for 39 of these mixtures. The solutes considered include aliphatic alcohols, amines, amides, ketones, fatty acids, amino acids, and sugars. In some cases, experimental data were available from which the temperature dependence of the quantities B and C could also be determined. The effect of solute size on the coefficients B and C was investigated using the lattice theories of Flory, Huggins, and Gu...

Solute‐Solute Interactions in Aqueous Solutions

The exact analytic expression for the mean time to absorption (or mean walk length) for a particle performing a random walk on a finite Sierpinski gasket with a trap at one vertex is found to be ${T}^{(n)}=[{3}^{n}{5}^{n+1}{+4(5}^{n})\ensuremath{-}{3}^{n}]{/(3}^{n+1}+1)$ where n denotes the generation index of the gasket, and the mean is over a set of starting points of the walk distributed uniformly over all the other sites of the gasket. In terms of the number ${N}_{n}$ of sites on the gasket and the spectral dimension $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{d}$ of the gasket, the precise asymptotic behavior for large ${N}_{n}$ is ${T}^{(n)}\ensuremath{\rightarrow}{1/3(2N}_{n}{)}^{2/\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{d}}\ensuremath{\sim}{N}^{1.464}.$ This serves as a partial check on our result, as it is (a) intermediate between the known results $T\ensuremath{\sim}{N}^{2}$ $(d=1)$ and $T\ensuremath{\sim}N\mathrm{ln}N$ $(d=2)$ for random walks on d-dimensional Euclidean lattices and (b) consistent with the known result for the asymptotic behavior of the mean number of distinct sites visited in a random walk on a fractal lattice.

Analytic expression for the mean time to absorption for a random walker on the Sierpinski gasket.

Reference LPI-ARTICLE-1980-006doi:10.1021/j100449a017View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12

Role of dimensionality and spatial extent in influencing intramicellar kinetic processes

Tertiary contact formation rates in α-synuclein, an intrinsically disordered polypeptide implicated in Parkinson's disease, have been determined from measurements of diffusion-limited electron-transfer kinetics between triplet-excited tryptophan:3-nitrotyrosine pairs separated by 10, 12, 55, and 90 residues. Calculations based on a Markovian lattice model developed to describe intrachain diffusion dynamics for a disordered polypeptide give contact quenching rates for various loop sizes ranging from 6 to 48 that are in reasonable agreement with experimentally determined values for small loops (10−20 residues). Contrary to expectations, measured contact rates in α-synuclein do not continue to decrease as the loop size increases (≥35 residues), and substantial deviations from calculated rates are found for the pairs W4−Y94, Y39−W94, and W4−Y136. The contact rates for these large loops indicate much shorter average donor−acceptor separations than expected for a random polymer.

/pdf/a-synuclein-tertiary-contact-dynamics-38dd62tp76.pdf

α-Synuclein Tertiary Contact Dynamics

We continue the study of a particle (atom, molecule) undergoing an unbiased random walk on the Sierpinski gasket, and obtain for the gasket and tower the eigenvalue spectrum of the associated stochastic master equation Analytic expressions for recurrence relations among the eigenvalues are derived The recurrence relations obtained are compared with those determined for two Euclidean lattices, the closed chain with an absorbing site and a finite chain with an absorbing site at one end We check and confirm the internal consistency between the smallest eigenvalue and the mean walklength in each of the cases studied Attention is drawn to the relevance of the results obtained to a problem of electron transfer in proteins

John J. Kozak

Papers

Solute‐Solute Interactions in Aqueous Solutions

Analytic expression for the mean time to absorption for a random walker on the Sierpinski gasket.

Role of dimensionality and spatial extent in influencing intramicellar kinetic processes

α-Synuclein Tertiary Contact Dynamics

Analytic expression for the mean time to absorption for a random walker on the Sierpinski gasket. II. the eigenvalue spectrum