Synthesis of an orange anthrathiophene pigment isolated from a Japanese bryozoan

A short, regiospecific synthesis of the naturally occurring anthrathiophene 1 from naphthazarin (7) is described.     

Continuous variable quantum teleportation with sculptured and noisy non-Gaussian resources

We investigate continuous variable (CV) quantum teleportation using relevant classes of non-Gaussian states of the radiation field as entangled resources. First, we introduce the class two-mode squeezed symmetric superposition of Fock states, including finite truncations of twin-beam Gaussian states as special realizations. These states depend on a set of free independent parameters that can be adjusted for the optimization of teleportation protocols, with an enhancement of the success probability of teleportation both for coherent and Fock input states. We show that the optimization procedure reduces the entangled resources to truncated twin beam states, which thus represents an optimal class of non-Gaussian resources for quantum teleportation. We then introduce a further class of two-mode non-Gaussian entangled resources, in the form of squeezed cat-like states. We analyze the performance and the properties of such states when optimized for (CV) teleportation, and compare them to the optimized squeezed Bell-like states introduced in a previous work [12]. We discuss how optimal resources for teleportation are characterized by a suitable balance of entanglement content and squeezed vacuum affinity. We finally investigate the effects of thermal noise on the efficiency of quantum teleportation. To this aim, a convenient framework is to describe noisy entangled resources as linear superpositions of non-Gaussian state and thermal states. Although the presence of the thermal component strongly reduces the teleportation fidelity, noisy non-Gaussian states remain preferred resources when compared to noisy twin-beam Gaussian states.     

The Tausk Controversy on the Foundations of Quantum Mechanics: Physics, Philosophy, and Politics

In 1966 the Brazilian physicist Klaus Tausk (b. 1927) circulated a preprint from the International Centre for Theoretical Physics in Trieste, Italy, criticizing Adriana Daneri,Angelo Loinger,and Giovanni Maria Prosperi’s theory of 1962 on the measurement problem in quantum mechanics. A heated controversy ensued between two opposing camps within the orthodox interpretation of quantum theory, represented by Léon Rosenfeld and Eugene P.Wigner. The controversy went well beyond the strictly scientific issues, however, reflecting philosophical and political commitments within the context of the Cold War, the relationship between science in developed and Third World countries, the importance of social skills, and personal idiosyncrasies.     

Isolation from pig liver microsomes, identification by electrospray tandem mass spectrometry and in vitro immunosuppressive activity of a rapamycin tris-epoxide metabolite

It was demonstrated that rapamycin is metabolized in vitro by pig liver microsomes under the influence of the cytochrome P450-dependent mixed function oxygenase system to a rapamycin tris-epoxide metabolite, as demonstrated by electrospray tandem mass spectrometry. The in vitro immunosuppressive activity of this metabolite was found to be lower than that of rapamycin, probably because the rapamycin effector sector was structurally modified. The effector region of rapamycin was recognized to include the conjugated double bonds of this compound and metabolic reactions affecting this region may change the binding affinity of the rapamycin-FKBP binary complex towards another pharmacological receptor bound to the binary complex. Moreover, metabolic modifications in the effector region are probably able to induce a change in the binding affinities of the rapamycin-FKBP binary complex, including the pipecolic acid moiety and the lactone function of the parent drug.     

Lawlike Reversibility, Factlike Irreversibility. The Symmetry of Time in Physics

Mehlberg's and Lewis' phrases in the title aptlyrender Boltzmann's and Gibbs' views. Statisticalcorrelation of physical events expresses theirinteration or propagated causality. Information, as(retarded) cognizance or as (advanced) organization, istied a la Reichenbach with Aristole's efficient or finalcauses. Correspondence between the classical and thequantal transition formulas is discussed, and CPT invariance of nonseparabilityemphasized.     

Microscopic fluorescence imaging of bulk defect clusters in KH(2)PO(4) crystals

A microscopic fluorescence imaging system is used to detect optically active centers located inside a transparent dielectric crystal. Defect centers in the bulk of KH(2)PO(4) crystals are imaged based on their near-infrared emission following photoexcitation. The spatial resolution of the system is 1mum in the image plane and 25mum in depth. The experimental results indicate the presence of a large number of optically active defect clusters in different KH(2)PO(4) crystals, whereas the concentration of these clusters depends on the crystal sector and growth method.     

Compactification of symmetric varieties

The symmetric varieties considered in this paper are the quotientsG/H, whereG is an adjoint semi-simple group over a fieldk of characteristic 2, andH is the fixed point group of an involutorial automorphism ofG which is defined overk. In the casek=C, De Concini and Procesi (1983) constructed a wonderful compactification ofG/H. We prove the existence of such a compactification for arbitraryk. We also prove cohomology vanishing results for line bundles on the compactification. Dedicated to the memory of C. Chevalley     

MRI of thermally denatured blood: methemoglobin formation and relaxation effects

Focal regions of T₁-shortening have been observed in magnetic resonance imaging (MRI)-monitored thermal ablations of perfused tissues. The aims of this study were two-fold: to find evidence for heat-induced conversion of hemoglobin (Hb) to methemoglobin (mHb), and to investigate the effects of heat treatment of in-vitro blood components upon their MR relaxation times. Spectrophotometric studies were performed to confirm the heat-induced formation of methemoglobin. Preparations of whole and fractionated blood, previously submitted to elevated temperatures of 40°C to 80°C, were imaged and the relaxation times were calculated. Optical absorption spectra of samples containing free Hb, heated to 60°C, showed increased light absorption at 630 nm, evident of mHb presence. Short T₁ values in whole blood (1.13 s) and packed red blood cell (0.65 s) compartments, heated at 60°C, compared to their baseline values (1.62 s and 0.83 s, respectively), were attributed to mHb formation. In relation to MRI-guided thermal interventions, these results suggest a possible explanation for observation of hyperintense regions on T₁-weighted images.     

Lee-Goldburg solid-state imaging.

A new approach to solid-state imaging (SSI) is presented. The method relies on narrowing the resonance line using the Lee-Goldburg sequence. The technique is easy to implement in practice and may find widespread applications in materials science.     

Two-Dimensional Numerical Simulations of Photon Scanning Tunneling Microscopy: Fourier Modal Method and R-Matrix Algorithm

Numerical simulation of a two-dimensional probe–object system for photon scanning tunneling microscope is presented. The R-matrix propagation algorithm incorporated into the Fourier modal method was used to achieve an extended capability for modeling of a realistic system consisting of both a probe and a sample. The type of the mode guided through the dielectric probe and the coupling of the near-field to fundamental guiding mode in the probe are discussed. The influence of the probe parameters on the near-field images is investigated. Three different probe shapes were simulated in the constant height scanning mode. The transmitted flux intensity through the probe was found to be strongly dependent on the tip shape. The analysis shows a good agreement of the obtained results with the available theoretical works and confirming experimental results. The proposed numerical scheme can find applications for near-field probe characterization and provides an understanding of the degree of perturbation introduced by a probe tip in the experiment.