Exotic axion cosmology in theories with phase transitions below the QCD scale

We show that axion phenomenology may be significantly different than conventionally assumed in theories which exhibit late phase transitions (below the QCD scale). In such theories, one can find multiple pseudoscalars with axionlike couplings to matter, including a string scale axion, whose decay constant far exceeds the conventional cosmological bound. Such theories have several dark matter candidates.     

Decay of quantum correlations in atom optics billiards with chaotic and mixed dynamics

We perform echo spectroscopy on ultracold atoms in atom-optics billiards to study their quantum dynamics. The detuning of the trapping laser is used to change the "perturbation", which causes a decay in the echo coherence. Two different regimes are observed: first, a perturbative regime in which the decay of echo coherence is nonmonotonic and partial revivals of coherence are observed in contrast with the predictions of random matrix theory. These revivals are more pronounced in traps with mixed dynamics as compared to traps where the dynamics is fully chaotic. Next, for stronger perturbations, the decay becomes monotonic and independent of the strength of the perturbation. In this regime no clear distinction can be made between chaotic traps and traps with mixed dynamics.     

Forty years of metrology with synchrotron radiation at SURF

The Canadian Light Source, the University of Western Ontario, IBM Canada and BigBangwidth during 2006 developed the Remote Beamline Access (RBA) system. This system was demonstrated using a standalone soft X-ray machine as well on the VESPERS beamline. The RBA system serves as a proof of concept and basis for ScienceStudio, which is now under development.     

Solitary Subgroups

We call a subgroup A of a finite group G a solitary subgroup of G if G does not contain another isomorphic copy of A. We call a normal subgroup A of a finite group G a normal solitary subgroup of G if G does not contain another normal isomorphic copy of A. The property of being (normal) solitary can be viewed as a strengthening of the requirement that A is normal in G. We derive various results on the existence of (normal) solitary subgroups.     

Improved mass accuracy for higher mass peptides by using SWIFT excitation for MALDI-FTICR mass spectrometry

Stepwise-external calibration has previously been shown to produce sub part-per-million (ppm) mass accuracy for the MALDI-FTICR/MS analyses of peptides up to m/z 2500. The present work extends these results to ions up to m/z 4000. Mass measurement errors for ions of higher mass-to-charge are larger than for ions below m/z 2500 when using conventional chirp excitation to detect ions. Mass accuracy obtained by using stored waveform inverse Fourier transform (SWIFT) excitation was evaluated and compared with chirp excitation. Analysis of measurement errors reveals that SWIFT excitation provides smaller deviations from the calibration equation and better mass accuracy than chirp excitation for a wide mass range and for widely varying ion populations.     

Electron transfer dissociation in the hexapole collision cell of a hybrid quadrupole-hexapole Fourier transform ion cyclotron resonance mass spectrometer

Electron transfer dissociation (ETD) of proteins is demonstrated in a hybrid quadrupole-hexapole Fourier transform ion cyclotron resonance mass spectrometer (Qh-FTICRMS). Analyte ions are selected in the mass analyzing quadrupole, accumulated in the hexapole linear ion trap, reacted with fluoranthene reagent anions, and then analyzed via an FTICR mass analyzer. The hexapole trap allows for a broad fragment ion mass range and a high ion storage capacity. Using a 3 T FTICRMS, resolutions of 60 000 were achieved with mass accuracies averaging below 1.4 ppm. The high resolution, high mass accuracy ETD spectra provided by FTICR obviates the need for proton transfer reaction (PTR) charge state reduction of ETD product ions when analyzing proteins or large peptides. This is demonstrated with the ETD of ubiquitin and apomyoglobin yielding sequence coverages of 37 and 20%, respectively. We believe this represents the first reported successful combination of ETD and a FTICRMS.     

Stretch‐Induced Drug Delivery from Superhydrophobic Polymer Composites: Use of Crack Propagation Failure Modes for Controlling Release Rates

The concept of using crack propagation in polymeric materials to control drug release and its first demonstration are reported. The composite drug delivery system consists of highly‐textured superhydrophobic electrosprayed microparticle coatings, composed of biodegradable and biocompatible polymers poly(caprolactone) and poly(glycerol monostearate carbonate‐co‐caprolactone), and a cellulose/polyester core. The release of entrapped agents is controlled by the magnitude of applied strain, resulting in a graded response from water infiltration through the propagating patterned cracks in the coating. Strain‐dependent delivery of the anticancer agents cisplatin and 7‐ethyl‐10‐hydroxycamptothecin to esophageal cancer cells (OE33) in vitro is observed. Finally the device is integrated with an esophageal stent to demonstrate delivery of fluorescein diacetate, using applied tension, to an ex vivo esophagus.     

Electron-impact fragmentation of aliphatic polynitro compounds

The mass spectra of two series of aliphatic polynitro compounds are reported and discussed. The fragmentation patterns of aliphatic nitro and polynitro compounds are similar in that no appreciable molecular ion current is observed; however, there are several other features in the fragmentation of aliphatic polynitro compounds which differ from that of nitroalkane spectra. Both series of compounds studied-C(NO₂)_x(CH₃)_4?x, where x = 4 to 0 and C₂(NO₂)_x(CH₃)_6?x, where x = 6,4,2-show a decrease in the number and intensity of alkylions with an increase in the NO⁺ and NO₂⁺ ion current as x increases. The main ions resulting from the more nitrated compounds are [NO]⁺, [NO₂]⁺, [CO₂]^+. and [CH₃CO]⁺, whose noncharged counterparts are the principal species produced in the detonation of these compounds. This similarity of the products of the two processes suggests the use of mass spectroscopy for the investigation of the initial explosive processes. The principal fragmentation pathways of the polynitroalkanes have been elucidated by exact mass measurements and the observation of metastable ion transitions.     

Model of “living” active centers in kinetics of the solid-phase polymerization

A model of “living” active centers in the solid phase has been developed, which are the complexes of a traditional active center (radical or ion) with a carrier of excessive free volume in solids, the structural defect (vacancy, polyvacancy, dislocation, crack). This model for the first time successfully explained the most nontrivial kinetic peculiarities of the solid-phase polymerization.     

Charge transfer complex formation in in-situ maleic anhydride and N-vinyl caprolactam copolymer and copolymer/organo-montmorillonite nanoarchitectures

The binary copolymerization of maleic anhydride (MA) and N-vinyl caprolactam (VCL) or considered as acceptor (A)?donor (D) monomer systems were used (MA:VCL) 50:50 in BPO (0.5%) as an initiator at 70°C under nitrogen atmosphere. The functional copolymers, having a combination of rigid/flexible linkages and an ability of complex-formation with interlayered surface of organo-silicate, and their nanocomposites have been synthesized. Interlamellar in situ complex-radical copolymerization of intercalated monomer complexes of MA and VCL undergoes with stearyl amine surface modified montmorillonite (O-MMT) and monomer mixtures. Charge transfer complex formation was followed and identified by UV-Vis-NIR spectroscopy. Equilibrium constant (K_AD) molar absorption coefficient (?^AD)) of the complex were determined by the Benesi-Hildebrand, Scott and Ketaalar equations respectively. The results show that copolymerization of MA:VCL system was preceded via alternating copolymerization mechanism. Obtained functional alternating copolymer and copolymer/O-MMT nanostructures were characterized by XRD and TEM.