1,504 research outputs found
Anti-cancer Action of Metal Complexes: Electron Transfer and Oxidative Stress?
Evidence is presented in support of an electron transfer mechanism for various metal complexes possessing anti-neoplastic properties. Cyclic voltammetry was performed on several metallocenes, bis(acetato)bis(imidazole)Cu(II), and coordination compounds (Cu or Fe) of the anti-tumor agents, bipyridine, phenanthroline, hydroxyurea, diethyldithiocarbamate, and α, α1-bis(8-hydroxyquinolin-7-yl)-4-methoxytoluene. The favorable reduction potentials ranged from +0.5 to -0.5 V. Electrochemical behavior is correlated in some cases with structure and physiological activity. Relevant literature data are discussed
Galoisian Approach to integrability of Schr\"odinger Equation
In this paper, we examine the non-relativistic stationary Schr\"odinger
equation from a differential Galois-theoretic perspective. The main algorithmic
tools are pullbacks of second order ordinary linear differential operators, so
as to achieve rational function coefficients ("algebrization"), and Kovacic's
algorithm for solving the resulting equations. In particular, we use this
Galoisian approach to analyze Darboux transformations, Crum iterations and
supersymmetric quantum mechanics. We obtain the ground states, eigenvalues,
eigenfunctions, eigenstates and differential Galois groups of a large class of
Schr\"odinger equations, e.g. those with exactly solvable and shape invariant
potentials (the terms are defined within). Finally, we introduce a method for
determining when exact solvability is possible.Comment: 62 page
On the interaction of the responses at the resonance frequencies of a nonlinear two degrees-of-freedom system
International audienceThis paper describes the dynamic behaviour of a coupled system which includes a nonlinear hardening system driven harmonically by a shaker. The shaker is modelled as a linear single degree-of-freedom system and the nonlinear system under test is modelled as a hardening Duffing oscillator. The mass of the nonlinear system is much less than the moving mass of the shaker and thus the nonlinear system has little effect on the shaker dynamics. The nonlinearity is due to the geometric configuration consisting of a mass suspended on four springs, which incline as they are extended. Following experimental validation, the model is used to explore the dynamic behaviour of the system under a range of different conditions. Of particular interest is the situation when the linear natural frequency of the nonlinear system is less than the natural frequency of the shaker such that the frequency response curve of the nonlinear system bends to higher frequencies and thus interacts with the resonance frequency of the shaker. It is found that for some values of the system parameters a complicated frequency response curve for the nonlinear system can occur; closed detached curves can appear as a part of the overall amplitude-frequency response. These detached curves can lie outside or inside the main resonance curve, and a physical explanation for their occurrence is given
Merger Control Procedures and Institutions: A Comparison of the EU and US Practice
The objective of this paper is to discuss and compare the role that different constituencies play in US and EU procedures for merger control. We describe the main constituencies (both internal and external) involved in merger control in both jurisdictions and discuss how a typical merger case would be handled under these procedures. At each stage, we consider how the procedure unfolds, which parties are involved, and how they can affect the procedure. Our discussion reveals a very different ecology. EU and US procedures differ in terms of their basic design and in terms of the procedures that are naturally associated with these alternative designs. On the one hand, there is a single investigator and decision maker operating under a symmetric mandate in the EU and on the other hand, an investigation and settlement operating under the threat of a court decision in case of challenge only in the US. The EU has developed numerous procedures and has granted extensive rights to the parties in the context of these procedures in order to provide some guarantee that the Commission’s role as investigator and decision maker at first instance is not abused. By contrast, the US procedures appear to be rather informal, the balance in the investigation and evaluation of the merger being provided by the credible threat of a court decision. With a strong federal government that has extensive competences for regulation, merger control on competition grounds is subject to the additional public interest test of regulators in the US. Such additional control is weak in the EU, which has more limited competences for regulation. In addition, both the executive and the legislative powers are more fully developed at the federal level in the US. Both the executive power and the legislative seem to be in position to wield greater influence on enforcement in the US than is the case in the EU
Non integrability of a self-gravitating Riemann liquid ellipsoid
We prove that the motion of a triaxial Riemann ellipsoid of homogeneous
liquid without angular momentum does not possess an additional first integral
which is meromorphic in position, impulsions, and the elliptic functions which
appear in the potential, and thus is not integrable. We prove moreover that
this system is not integrable even on a fixed energy level hypersurface.Comment: 14 pages, 8 reference
Misterios de la vida de Jesucristo en la puerta de madera de la catedral de Split
La catedral de Split es, de hecho, el ex mausoleo del emperador Diocleciano, transformado en Iglesia. La catedral fue enriquecida durante el siglo xiii con varias obras escultóricas románicas de gran maestría. Entre ellas destacan la puerta de madera de doble batiente con escenas que representan los misterios de la vida de Cristo, esculpidas como bajorrelieves por el artista Andrija Buvina, natural de Split, inaugurada el 23 de abril del 1214. Entre las pocas puertas de madera medievales que conservamos es la única que se encuentra aún in situ y en un buen estado de conservación.
Sobre cada una de las hojas de la puerta se encuentran siete pares de escenas en bajorrelieve que representan la vida, la muerte y la gloria de Cristo Redentor. Esta
puerta está considerada, con razón, como una obra maestra de la escultura medieval en Croacia. La clave iconológica de la obra de Buvina consiste en la mistagogia cristológica y soteriológica de las escenas de la vida del Salvador. ---------------- Split Cathedral is the former mausoleum of the Emperor Diocletian which was transformed into a church. The Cathedral was embellished in the 13th century with several magnificent Romanesque sculptures. Outstanding among these is the double wooden door decorated with scenes representing the life of Christ, carved as a bas-relief by Andrija Buvina, a native of Split, which was inaugurated
on 23 April 1214. Of the few medieval wooden doors that are still preserved, this is the only example that is still in its original position and in a good state of conservation.
Both of the doors contain seven pairs of scenes in basrelief representing the life, death and glory of Christ the Redeemer. This door is rightly regarded as a master work
of medieval sculpture in Croatia. The iconological key to Buvina’s work lies in the Christological mystagogy and soteriology
of the life our Our Lord
Arene oxidation with malonoyl peroxides
Malonoyl peroxide 7, prepared in a single step from the commercially available diacid, is an effective reagent for the
oxidation of aromatics. Reaction of an arene with peroxide 7 at room temperature leads to the corresponding protected phenol
which can be unmasked by aminolysis. An ionic mechanism consistent with the experimental findings and supported by isotopic
labeling, Hammett analysis, EPR investigations and reactivity profile studies is proposed
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