New Limit on the Permanent Electric Dipole Moment of ^{129}Xe Using ^{3}He Comagnetometry and SQUID Detection

We report results of a new technique to measure the electric dipole moment of ^{129}Xe with ^{3}He comagnetometry. Both species are polarized using spin-exchange optical pumping, transferred to a measurement cell, and transported into a magnetically shielded room, where SQUID magnetometers detect free precession in applied electric and magnetic fields. The result from a one week measurement campaign in 2017 and a 2.5 week campaign in 2018, combined with detailed study of systematic effects, is d_{A}(^{129}Xe)=(1.4±6.6_{stat}±2.0_{syst})×10^{-28}  e cm. This corresponds to an upper limit of |d_{A}(^{129}Xe)|<1.4×10^{-27}  e cm (95% C.L.), a factor of 5 more sensitive than the limit set in 2001.

Application unit for the administration of contrast gases for pulmonary magnetic resonance imaging: optimization of ventilation distribution for (3) He-MRI

PURPOSE

MRI of lung airspaces using gases with MR-active nuclei ((3) He, (129) Xe, and (19) F) is an important area of research in pulmonary imaging. The volume-controlled administration of gas mixtures is important for obtaining quantitative information from MR images. State-of-the-art gas administration using plastic bags (PBs) does not allow for a precise determination of both the volume and timing of a (3) He bolus.

METHODS

A novel application unit (AU) was built according to the requirements of the German medical devices law. Integrated spirometers enable the monitoring of the inhaled gas flow. The device is particularly suited for hyperpolarized (HP) gases (e.g., storage and administration with minimal HP losses). The setup was tested in a clinical trial (n = 10 healthy volunteers) according to the German medicinal products law using static and dynamic ventilation HP-(3) He MRI.

RESULTS

The required specifications for the AU were successfully realized. Compared to PB-administration, better reproducibility of gas intrapulmonary distribution was observed when using the AU for both static and dynamic ventilation imaging.

CONCLUSION

The new AU meets the special requirements for HP gases, which are storage and administration with minimal losses. Our data suggest that gas AU-administration is superior to manual modes for determining the key parameters of dynamic ventilation measurements.

Magnetized boxes for housing polarized spins in homogeneous fields

We present novel types of permanently magnetized as well as current powered boxes built from soft-ferromagnetic materials. They provide shielded magnetic fields which are homogeneous within a large fraction of the enclosed volume, thus minimizing size, weight, and costs. For the permanently magnetized solutions, homogenization is achieved either by an optimized distribution of the permanent field sources or by jacketing the field with a soft-ferromagnetic cylindrical shell which is magnetized in parallel to the enclosed field. The latter principle may be applied up to fields of about 0.1T. With fields of about 1mT, such boxes are being used for shipping spin-polarized (3)He worldwide for MRI purposes. For current powered boxes, we present concepts and realizations of uniaxial and tri-axial shielded magnetic fields which are homogeneous on the level of 10(-4) within the entire shielded volume. This is achieved by inserting tightly fitting solenoids into a box from soft-magnetic material. The flexible tri-axial solution suits in particular laboratory applications, e.g. for establishing a spin quantization axis.

Effect of Ramadan fasting on fuel oxidation during exercise in trained male rugby players

PURPOSE

The aim of this study was to assess the effect of Ramadan fasting on substrate oxidation in trained athletes during moderate-intensity exercise.

METHODS

Nine trained men (age: 19+/-2 yr, Height: 1.78+/-0.74 m) were tested on three occasions: during a control period immediately before Ramadan (C), at the end of the first week (Beg-R), and during the fourth week of Ramadan (End-R). On each occasion, they performed submaximal cycle ergometer exercise, with work-rates that were increased progressively (loadings corresponding to 20, 30, 40, 50, 60% of Wmax). Steady-state substrate oxidation was evaluated by indirect calorimetry.

RESULTS

Participants showed significant decreases in body mass and body fat at the end of Ramadan, relative to initial control values (P<0.001). The daily food intake was also reduced during Ramadan (P<0.01). Haemoglobin concentrations and hematocrit were significantly higher at the end-Ramadan, both at rest (P<0.001 and P<0.0001 respectively) and after exercise, (P<0.05 and P<0.01 respectively) compared to control measurements made before Ramadan. At the end of Ramadan, our subjects had increased their fat utilization during exercise. The cross-over was observed at a higher intensity at the End-R (35% vs. 30% of Wmax, P<0.001). For the same power output, the Lipox max was also higher at the End-R, compared to control value (265+/-38 vs. 199.1+/-20 mg/min, P<0.001).

CONCLUSION

Ramadan fasting increases the lipid oxidation of trained athletes during submaximal exercise. The increased fat utilisation may be related to decreases in body mass and body fat content.