A direct route for the preparation of Fmoc/OtBu protected iodotyrosine

Herein the synthesis of an Fmoc/O^tBu orthogonally protected iodotyrosine derivative is reported. This has been achieved via a simple two-step process in an overall 58% yield from commercially available Fmoc-Tyr(^tBu)-OH. The Fmoc/O^tBu orthogonally protected iodotyrosine was also shown to be amenable to Suzuki-Miyaura cross-coupling to deliver a novel bi-aryl tyrosine derivative.     

Cage motion of a probe atom in a vacancy complex in Pt

The perturbation function of a Cd probe atom bound in a hydrogen-decorated vacancy complex in Pt is found to exhibit dynamical relaxation at 294 K, as measured by the technique of perturbed γ-γ angular correlations. Based on other characteristics of the complex, a model is proposed for the structure of the complex. In the undecorated state, it consists of a probe atom at the center of a tetrahedron of vacancies in the fcc structure. In the decorated state at low temperature, the probe atom returns to one of the four vacant lattice sites. The relaxation at room temperature is attributed to motion of the probe atom in a cage formed by the four vacant sites.     

Euclidean field theory

The extension of the Schwinger functions to various positive linear functionals on the Borchers algebra is discussed. In one case, we construct a measure onL and give criteria for uniqueness as well as for the homogeneous chaos to lead to an ?₂-space.     

Chemiluminescence of IF in the gas phase reaction of I2 with F2

Emission from both the state and the previously unreported $\text{A}{}^3\text{Π}{}_1$ state of IF has been observed in the gas phase reaction of I₂ with F₂ at low pressures. For the state the transition moment and vibrational populations were extracted from the spectra by a least-squares method whereby theoretical band shapes were fit to the experimental data. The effect of flow rates of reactants and Ar on the relative emission from the two electronic states, the effect of pressure on the state, and extinction of emission near 470 nm all favor the population of excited electronic states through a four-center reaction complex, rather than association of F and I atoms.It is argued that there is an avoided curve crossing between the lowest two ³Π_0⁺ states of IF, and that the ground state dissociation energy is 23 229 ± 100 cm^?1. The radiative lifetime of the state is estimated to be 10^?3 sec and to be much shorter than that of the $\text{A}{}^3\text{Π}{}_1$ state.     

Nonlocality Without Nonlocality

Bell’s theorem is purported to demonstrate the impossibility of a local “hidden variable” theory underpinning quantum mechanics. It relies on the well-known assumption of ‘locality’, and also on a little-examined assumption called ‘statistical independence’ (SI). Violations of this assumption have variously been thought to suggest “backward causation”, a “conspiracy” on the part of nature, or the denial of “free will”. It will be shown here that these are spurious worries, and that denial of SI simply implies nonlocal correlation between spacelike degrees of freedom. Lorentz-invariant theories in which SI does not hold are easily constructed: two are exhibited here. It is conjectured, on this basis, that quantum-mechanical phenomena may be modeled by a local theory after all. This paper is dedicated to the memory of John A. Wheeler.     

Equilibrium with strategy-dependent trembles

Trembling-hand arguments, introduced by Selten, where players make errors in implementing a strategy, are a successful and intuitively plausible approach to eliminating some equilibria. Typically, these errors are independent of the strategy the player aims to implement. In many contexts, however, when a player aims at one strategy, some errors are more likely than if a different strategy is the target. We introduce the notion of strategy-dependent trembles where each strategy intended by a player implies a different probability vector of errors over other strategies. This seemingly minor but plausible change makes a major difference. The focus becomes a player's own errors rather than the errors of others. A weakly dominated strategy is not necessarily eliminated if less costly errors arise when aiming at it than at the dominating strategy. Almost every Nash equilibrium in pure strategies is a strategy-dependent trembling-hand perfect equilibrium. We thank the associate editor, two referees, James Friedman, and audiences at the Public Choice Society Meetings and Southeastern Economic Theory Meetings for comments and the Public Utility Research Center and the College of Business Administration at the University of Florida for financial support.     

Nuclear magnetic resonance relaxometry of the normal heart: Relationship between collagen content and relaxation times of the four chambers

The use of nuclear magnetic resonance (NMR) relaxation time measurements for characterization of abnormal cardiac tissue depends upon knowledge of variations of relaxation times of normal myocardium and determinants of these variations. We calculated in vitro NMR T₁ and T₂ relaxation times of canine myocardium from the four cardiac chambers, and determined hydroxyproline concentration (as a measure of collagen) and percent water content of the samples. We found both water content and T₁ relaxation time of the right ventricle to be significantly greater than the left atrium (p < 0.05). T₂ relaxation time of the left ventricle was found to be shorter than each of the other three chambers (p < 0.05). There were significant correlations between the spin-lattice relaxation time and both percent water content (r = 0.58) and hydroxyproline concentration (r = 0.45). A significant correlation was also found between T₂ relaxation time and hydroxyproline concentration (r = 0.49). When T₁ and T₂ were adjusted for water and hydroxyproline content, there was no longer any evidence for significant interchamber differences for either T₁ or T₂. These data suggest that differences in NMR relaxation times exist among the four chambers of the normal canine heart. Furthermore, a major determinant of myocardial spin-lattice relaxation time is tissue water content while both collagen content and percent water content significantly contribute to variability in cardiac chamber T₂ relaxation times.     

On the Frequency of Zeros of Solutions of Second Order Linear Differential Equations

We consider the equation \(\rm f^{\prime\prime}+{A}(z){f}=0\) with linearly independent solutions f₁,₂, where A(z) is a transcendental entire function of finite order. Conditions are given on A(z) which ensure that max{λ(f₁),λ(f₂)} = ∞, where λ(g) denotes the exponent of convergence of the zeros of g. We show as a special case of a further result that if P(z) is a non-constant, real, even polynomial with positive leading coefficient then every non-trivial solution of \(\rm f^{\prime\prime}+{e}^P{f}=0\) satisfies λ(f) = ∞. Finally we consider the particular equation \(\rm f^{\prime\prime}+({e}^Z-K){f}=0\) where K is a constant, which is of interest in that, depending on K, either every solution has λ(f) = ∞ or there exist two independent solutions f₁, f₂ each with λ(f_i) ≤ 1.