Deformation of a trapped Fermi gas with unequal spin populations

The real-space densities of a polarized strongly interacting two-component Fermi gas of 6Li atoms reveal two low-temperature regimes, both with a fully paired core. At the lowest temperatures, the unpolarized core deforms with increasing polarization. Sharp boundaries between the core and the excess unpaired atoms are consistent with a phase separation driven by a first-order phase transition. In contrast, at higher temperatures the core does not deform but remains unpolarized up to a critical polarization. The boundaries are not sharp in this case, indicating a partially polarized shell between the core and the unpaired atoms. The temperature dependence is consistent with a tricritical point in the phase diagram.     

Diffusion tensor magnetic resonance imaging of the normal breast

Purpose

The objective of this study was to evaluate diffusion anisotropy of the breast parenchyma and assess the range and repeatability of diffusion tensor imaging (DTI) parameters in normal breast tissue.

Materials and Methods

The study was approved by our institutional review board and included 12 healthy females (median age, 36 years). Diffusion tensor imaging was performed at 1.5 T using a diffusion-weighted echo planar imaging sequence. Diffusion tensor imaging parameters including tensor eigenvalues (λ₁, λ₂, λ₃), fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured for anterior, central and posterior breast regions.

Results

Mean normal breast DTI measures were λ₁=2.51×10⁻³ mm²/s, λ₂=1.89×10⁻³ mm²/s, λ₃=1.39×10⁻³ mm²/s, ADC=1.95±0.24×10⁻³ mm²/s and FA=0.29±0.05 for b=600 s/mm². Significant regional differences were observed for both FA and ADC (P<.05), with higher ADC in the central breast and higher FA in the posterior breast. Comparison of DTI values calculated using b=0, 600 s/mm² vs. b=0, 1000 s/mm², showed significant differences in ADC (P<.001), but not FA. Repeatability assessment produced within-subject coefficient of variations of 4.5% for ADC and 11.4% for FA measures.

Conclusion

This study demonstrates anisotropy of water diffusion in normal breast tissue and establishes a normative range of breast FA values. Attention to the influence of breast region and b value on breast DTI measurements may be important for clinical interpretation and standardization of techniques.     

HPLC–MS Profiling and Structural Identification of [14C]-Diclofenac Metabolites in Mouse Bile

Biliary metabolites present at 6 h post-dose following a single oral dose of [¹⁴C]-diclofenac (10 mg kg^?1) to male bile duct-cannulated C57BL/6 J mice were profiled and identified. Over the 6 h duration of the study ~19.5 % of the administered radioactivity was excreted into the bile as either [¹⁴C]-diclofenac or metabolites. When profiled using HPLC with online radiodetection, the presence of at least 13 radiolabelled components was indicated. These compounds were shown, by consecutive reaction mass spectrometry, to comprise a range of hydroxylated metabolites conjugated to either taurine, glucose and/or glucuronic acid. Both phenolic and acylglucuronide-containing metabolites were observed. The confirmation of the presence of these glucuronide conjugates in mouse bile may have important consequences in the light of emerging theories concerning the role of bacterial glucuronidases for the GI-tract toxicity of NSAIDs such as diclofenac.     

Plasma Copolymerization of Pyrrole with Si-Compounds

The plasma copolymerization of pyrrole with hexamethyldisiloxane, hexamethyldisilane and hexamethyldisilazane was investigated with regard to the polymer deposition characteristics and the properties of the product films. Deposition rates were evaluated by monitoring the weight increase of the deposits over time, and the effect of varying the experimental set up parameters was determined. The results of deposition rates and quantitative IR analysis suggested that the increasing amounts of Si-components were incorporated into the polymer matrix as the supply ratio of the Si-monomer was increased. The Si-component in the copolymer brought some dramatic effects on the physical properties of the films and changed the hydrophobicity of the surfaces, as reflected in the advancing and receding contact angle measurements. The experimental results obtained are discussed in terms of the contribution of the polar and dispersion components of surface energy.     

Studies of relativistic backward-wave oscillator operation in thecross-excitation regime

We first reported the operation of a relativistic backward-wave oscillator (BWO) in the so-called cross-excitation regime in 1998. This instability, whose general properties were predicted earlier through numerical studies, resulted from the use of a particularly shallow rippled-wall waveguide [slow wave structure (SWS)] that was installed in an experiment to diagnose pulse shortening in a long-pulse electron beam-driven high-power microwave (HPM) source. This SWS was necessary to accommodate laser interferometry measurements along the SWS during the course of microwave generation. Since those early experiments, we have studied this regime in greater detail using two different SWS lengths. We have invoked time-frequency analysis, the smoothed-pseudo Wigner-Ville distribution in particular, to interpret the heterodyned signals of the radiated power measurements. These recent results are consistent with earlier theoretical predictions for the onset and voltage scaling for this instability. This paper presents data for a relativistic BWO operating in the single-frequency regime for two axial modes, operating in the cross-excitation regime, and discusses the interpretation of the data, as well as the methodology used for its analysis. Although operation in the cross-excitation regime is typically avoided due to its poorer efficiency, it may prove useful for future HPM effects studies     

Effect of crystallographic orientation on the anodic formation of nanoscale pores/tubes in TiO2 films

Self-organized nanopores and nanotubes have been produced in thin films of titanium (Ti) prepared using filtered cathodic vacuum arc (FCVA), DC- and RF-sputter deposition systems. The anodization process was performed using a neutral electrolyte containing fluoride ions with an applied potential between 2 and 20 V (for clarity the results are only presented for 5 V). Scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques were used to characterise the films. It was found that the crystallographic orientation of the Ti films played a significant role in determining whether pores or tubes were formed during the anodic etching process.     

Application of the lithiation-borylation reaction to the rapid and enantioselective synthesis of the bisabolane family of sesquiterpenes

The expedient enantioselective synthesis of 5 bisabolane sesquiterpenes has been achieved using a common, one-pot lithiation-borylation reaction of secondary benzylic carbamates and either protodeboronation or oxidation to give the natural products in fewer than 5 steps, with high yield and >94?:?6 er.