(Higgs)2, 3 quantum fields in a finite volume

This is the third paper of a series, and contains a proof of the bounds on the effective actions needed in the two previous papers. The proof is based on perturbative analysis of renormalization.     

Empirical parameters of lewis acidity and basicity for aqueous binary solvent mixtures

Empirical parameters of Lewis acidity, E^N_T, introduced by Reichardt et al., and Lewis basicity, B_KT , introduced by Kamlet and Taft, have been determined for mixtures of water with ten organic solvents. In the case of water/alcohol mixtures a distinct dependence between these acidity and basicity parameters have been found. For the other solvent mixtures the E^N_T on B_KT dependence is more complex even if these parameters are purified from non-specific solute/solvent interactions.     

Meso-[2.2]paracyclophanyltriphenylporphyrin: A simple representative of cyclophanylporphyrins

(R + S)Meso-[2.2]Paracyclophanyltriphenylporphyrin 3 , a member of a novel class of cyclophanylporphyrins, was obtained and characterized by spectroscopic and electrochemical methods. Compared to meso-tetra[2.2]paracyclophanylporphyrin 1, it represents a simplified structure designed for the investigation of electronic interactions between the [2.2]paracyclophane moiety and porphyrin core and for use in metallation reactions.     

(Higgs)2,3 quantum fields in a finite volume

This is the second part of the paper entitled, “(Higgs)_2,3 Quantum Fields in a Finite Volume.” The proof of an upper bound for vacuum energy is completed with the exception of some technical estimates.     

Natural bond orbital (NBO) analysis of the angular group induced bond alternation (AGIBA) substituent effect

The geometries, natural charges, and resonance structures of 11 monosubstituted benzene derivatives were analyzed at the B3LYP/6‐311++G(d,p) and HF/6‐311++G(d, p) levels of theory. The following angular substituents were chosen: OCH₃, CH₂CH₃, OH, SH, NHCH₃, NHNH₂, N?O, CH?CH₂, N?CH₂, N?NH, and CHO. The analysis of resonance structures was performed by using two different methodologies: harmonic oscillator stabilization energies (HOSE) and natural resonance theory (NRT). Also, the natural bond orbital (NBO) donor–acceptor stabilization energies for different resonance structures were calculated. We found that for all the substituents, the purely geometric resonance stabilization parameter (HOSE) is linearly correlated with quantum chemically derived resonance structure weight (NRT) of a given structure. Also, the calculations provide qualitative support for the earlier assumption of a through space angular group induced bond alternation (AGIBA) effect. Copyright © 2010 John Wiley & Sons, Ltd.     

Field asymmetric waveform ion mobility spectrometry studies of proteins: Dipole alignment in ion mobility spectrometry?

Approaches to separation and characterization of ions based on their mobilities in gases date back to the 1960s. Conventional ion mobility spectrometry (IMS) measures the absolute mobility, and field asymmetric waveform IMS (FAIMS) exploits the difference between mobilities at high and low electric fields. However, in all previous IMS and FAIMS experiments ions experienced an essentially free rotation; thus the separation was based on the orientationally averaged cross-sections Omega(avg) between ions and buffer gas molecules. Virtually all large ions are permanent electric dipoles that will be oriented by a sufficiently strong electric field. Under typical FAIMS conditions this will occur for dipole moments >400 D, found for many macroions including most proteins above approximately 30 kDa. Mobilities of aligned dipoles depend on directional cross-sections Omega(dir) (rather than Omega(avg)), which should have a major effect on FAIMS separation parameters. Here we report the FAIMS behavior of electrospray-ionization-generated ions for 10 proteins up to approximately 70 kDa. Those above 29 kDa exhibit a strong increase of mobility at high field, which is consistent with predicted ion dipole alignment. This effect expands the useful FAIMS separation power by an order of magnitude, allowing separation of up to approximately 10(2) distinct protein conformers and potentially revealing information about Omega(dir) and ion dipole moment that is of utility for structural characterization. Possible approaches to extending dipole alignment to smaller ions are discussed.