Electric-Field-Controlled Cold Dipolar Collisions between Trapped CH_{3}F Molecules.

Reaching high densities is a key step toward cold-collision experiments with polyatomic molecules. We use a cryofuge to load up to 2×10^{7} CH_{3}F molecules into a boxlike electric trap, achieving densities up to 10^{7}/cm^{3} at temperatures around 350 mK where the elastic dipolar cross section exceeds 7×10^{-12} cm^{2}. We measure inelastic rate constants below 4×10^{-8} cm^{3}/s and control these by tuning a homogeneous electric field that covers a large fraction of the trap volume. Comparison to ab initio calculations gives excellent agreement with dipolar relaxation. Our techniques and findings are generic and immediately relevant for other cold-molecule collision experiments.

Low magnetic Johnson noise electric field plates for precision measurement.

We describe a parallel pair of high voltage electric field plates designed and constructed to minimise magnetic Johnson noise. They are formed by laminating glass substrates with a commercially available polyimide (Kapton) tape, covered with a thin gold film. Tested in vacuum, the outgassing rate is less than 5 × 10-5 mbar l/s. The plates have been operated at electric fields up to 8.3 kV/cm, when the leakage current is at most a few hundred pA. The design is discussed in the context of a molecular spin precession experiment to measure the permanent electric dipole moment of the electron.

Design and fabrication of diffractive atom chips for laser cooling and trapping.

It has recently been shown that optical reflection gratings fabricated directly into an atom chip provide a simple and effective way to trap and cool substantial clouds of atoms (Nshii et al. in Nat Nanotechnol 8:321-324, 2013; McGilligan et al. in Opt Express 23(7):8948-8959, 2015). In this article, we describe how the gratings are designed and microfabricated and we characterise their optical properties, which determine their effectiveness as a cold atom source. We use simple scalar diffraction theory to understand how the morphology of the gratings determines the power in the diffracted beams.

Weight loss in patients treated long-term with levodopa. Metabolic aspects.

Seven aged Parkinsonian patients treated with levodopa (average dose 3-4 g daily for 1-3 years), showed a considerable weight loss. They were compared to two control groups of elderly and young volunteers after levodopa stimulation and after oral glucose tolerance tests. It was found that after levodopa administration the plasma free fatty acids, glucose, growth hormone and cortisol were significantly higher in the Parkinsonian group than in the young control group and only slightly higher than in the aged control group. It was also found that the serum insulin was significantly higher in Parkinsonian patients than in the aged control group. We think that the metabolic disturbances found in Parkinsonian patients are not solely due to levodopa administration but may be due to ageing processes. We suggest that weight loss in the older Parkinsonian patients treated over long periods with high doses of levodopa, is due to the enhancement of the lipolytic activity of the ageing fat cells caused by high levels of circulating insulin.

Migraine attacks. Alleviation by an inhibitor of prostaglandin synthesis and action.

Twenty-six patients with migraine attacks were treated for 3 to 16 months with flufenamic acid (125 mg four to six times per attack), an inhibitor of prostaglandin synthesis and action. In 25 patients the drug afforded symptomatic relief in 195 of 200 treated attacks. Side effects observed were mild dyspepsia (eight patients) and severe upper gastrointestinal symptoms (two patients). None of the eight patients treated with placebo reported any relief (20 attacks). The "common" antimigraine drugs afforded symptomatic relief in 12 of the patients, partial relief in seven, and no relief in seven. Treatment with flufenamic acid was based on the hypothesis that prostaglandins are involved in migraine attack and that the drug relieves migraine by inhibition of the vasoactivity of prostaglandins.