Forcing axioms and the Galvin number

Periodica Mathematica Hungarica - We study the Galvin property. We show that various square principles imply that the cofinality of the Galvin number is uncountable (or even greater than $$\aleph...     

On the verge of inconsistency: Magidor cardinals and Magidor filters

We introduce a model-theoretic characterization of Magidor cardinals, from which we infer that Magidor filters are beyond ZFC-inconsistency.     

The Influence of the Radiofrequency Excitation and Conversion Pulses on the Lineshapes and Intensities of the Triple-Quantum MAS NMR Spectra of I = 3/2 Nuclei

A rigorous examination of the various multiple-quantum magic angle spinning sequences is carried out with reference to sensitivity enhancement in the isotropic dimension and the lineshapes of the corresponding MAS peaks in the anisotropic dimension. An echo efficiency parameter is defined here, which is shown to be an indicator of the performance aspects of the various sequences. This can be used in the design of further new experiments in this field. A consequence of such a systematic analysis has been the combination of a spin-lock pulse for excitation of multiple-quantum coherences and an amplitude-modulated pulse for their conversion to observable single-quantum coherences. This approach has resulted in an improved performance over other sequences with respect to both the anisotropic lineshapes and the isotropic intensities.     

Optimization of gain-assisted waveguiding in metal-dielectric nanowires

We theoretically demonstrate that, for a given diameter of the core-pumped metal-dielectric nanowire, there is an optimum thickness of the metallic cladding that provides the maximum propagation length of the lowest-order surface plasmon polariton (SPP) modes. If the nanowire is fabricated with the optimum cladding thickness, the lowest pumping power is required to fully compensate for the SPP propagation losses. We also show that a strong confinement of SPPs within the nanowire can be achieved, but at the expense of either high optical gains or large nanowire diameters. For example, a gain of 565 cm(-1) would suffice to make up for the decay of SPPs in a 250-nm-thick silver-GaAs nanowire; the confinement of optical power within such nanowires exceeds 90%, which makes them ideal interconnects for nanophotonic circuitry.     

Tiltan

We prove the consistency of ? with the negation of Galvin's property. On the other hand, we show that superclub implies Galvin's property. We also prove the consistency of ${?}_{{\kappa }^{+}}$ with ${\mathfrak{s}}_{\kappa }>{\kappa }^{+}$ for a supercompact cardinal κ.     

Direct hydrogenation of amides to alcohols and amines under mild conditions

The selective, direct hydrogenation of amides to the corresponding alcohols and amines with cleavage of the C-N bond was discovered. The expected products of C-O cleavage are not formed (except as traces in the case of anilides). The reaction proceeds under mild pressure and neutral, homogeneous conditions using a dearomatized, bipyridyl-based PNN Ru(II) pincer complex as a catalyst. The postulated mechanism involves metal-ligand cooperation by aromatization-dearomatization of the heteroaromatic pincer core and does not involve hydrolytic cleavage of the amide. The simplicity, generality, and efficiency of this environmentally benign process make it attractive for the direct transformations of amides to alcohols and amines in good to excellent yields.     

Minimization of negative phenomena arising at rectification of reactive mixtures

Using the technology of ethyl alcohol production as an example, a scheme of the transformation of admixed components in rectifying columns was considered and procedures for the minimization of negative side processes by chemical and instrumental-technological methods were offered.     

A top down approach to protein structural studies using chemical cross-linking and Fourier transform mass spectrometry

Mass spectrometric analysis of wild-type proteins that have been covalently modified by bifunctional cross-linking reagents and then digested proteolytically can be used to obtain low-resolution distance constraints, which can be useful for protein structure determination. Limitations of this approach include time-consuming separation steps, such as the separation of internally cross-linked protein monomers from covalent dimers, and a susceptibility to artifacts due to low levels of natural and man-made peptide modifications that can be mistaken for cross-linked species. The results presented here show that when a crude cross-linked protein mixture is injected into an electrospray ionization Fourier transform mass spectrometry (ESI-FTMS) instrument, the cross-link positions can be localized by fragmentation and mass spectrometry on the 'gas-phase purified' singly internally cross-linked monomer. Our results show that reaction of ubiquitin with the homobifunctional lysine-lysine cross-linking reagent dissuccinimidyl suberate (DSS) resulted in two cross-links consistent with the known ubiquitin tertiary structure (K6-K11 and K48-K63). Because no protein or peptide chemistry steps are needed, other than the initial cross-linking, this new top down approach appears well suited for high-throughput experiments with multiple cross-linkers and reaction conditions. Published in 2002 by John Wiley & Sons, Ltd.