Muonic atom spectroscopy with microgram target material.

Muonic atom spectroscopy-the measurement of the x rays emitted during the formation process of a muonic atom-has a long standing history in probing the shape and size of nuclei. In fact, almost all stable elements have been subject to muonic atom spectroscopy measurements and the absolute charge radii extracted from these measurements typically offer the highest accuracy available. However, so far only targets of at least a few hundred milligram could be used as it required to stop a muon beam directly in the target to form the muonic atom. We have developed a new method relying on repeated transfer reactions taking place inside a 100 bar hydrogen gas cell with an admixture of 0.25% deuterium that allows us to drastically reduce the amount of target material needed while still offering an adequate efficiency. Detailed simulations of the transfer reactions match the measured data, suggesting good understanding of the processes taking place inside the gas mixture. As a proof of principle we demonstrate the method with a measurement of the 2p-1s muonic x rays from a 5  µ g gold target.

ß-Nuclear-Recoil Correlation from

We report the first precise measurement of a ß-recoil correlation from a radioactive noble gas (^{6}He) confined via a magneto-optical trap. The measurement is motivated by the search for exotic tensor-type contributions to the charged weak current. Interpreted as tensor currents with right-handed neutrinos, the measurements yield |C_{T}/C_{A}|^{2}≤0.022 (90% confidence limit, C.L.). On the other hand, for left-handed neutrinos the limits are 0.007

Demonstration of Muon-Beam Transverse Phase-Space Compression.

We demonstrate efficient transverse compression of a 12.5 MeV/c muon beam stopped in a helium gas target featuring a vertical density gradient and crossed electric and magnetic fields. The muon stop distribution extending vertically over 14 mm was reduced to a 0.25 mm size (rms) within 3.5 µs. The simulation including cross sections for low-energy µ^{+}-He elastic and charge exchange (µ^{+}↔ muonium) collisions describes the measurements well. By combining the transverse compression stage with a previously demonstrated longitudinal compression stage, we can improve the phase space density of a µ^{+} beam by a factor of 10^{10} with 10^{-3} efficiency.

Measurement of the Permanent Electric Dipole Moment of the Neutron.

We present the result of an experiment to measure the electric dipole moment (EDM) of the neutron at the Paul Scherrer Institute using Ramsey's method of separated oscillating magnetic fields with ultracold neutrons. Our measurement stands in the long history of EDM experiments probing physics violating time-reversal invariance. The salient features of this experiment were the use of a ^{199}Hg comagnetometer and an array of optically pumped cesium vapor magnetometers to cancel and correct for magnetic-field changes. The statistical analysis was performed on blinded datasets by two separate groups, while the estimation of systematic effects profited from an unprecedented knowledge of the magnetic field. The measured value of the neutron EDM is d_{n}=(0.0±1.1_{stat}±0.2_{sys})×10^{-26} e.cm.

White matter integrity, hippocampal volume, and cognitive performance of a world-famous nonagenarian track-and-field athlete.

Physical activity (PA) and cardiorespiratory fitness (CRF) are associated with successful brain and cognitive aging. However, little is known about the effects of PA, CRF, and exercise on the brain in the oldest-old. Here we examined white matter (WM) integrity, measured as fractional anisotropy (FA) and WM hyperintensity (WMH) burden, and hippocampal (HIPP) volume of Olga Kotelko (1919-2014). Olga began training for competitions at age of 77 and as of June 2014 held over 30 world records in her age category in track-and-field. We found that Olga's WMH burden was larger and the HIPP was smaller than in the reference sample (58 healthy low-active women 60-78 years old), and her FA was consistently lower in the regions overlapping with WMH. Olga's FA in many normal-appearing WM regions, however, did not differ or was greater than in the reference sample. In particular, FA in her genu corpus callosum was higher than any FA value observed in the reference sample. We speculate that her relatively high FA may be related to both successful aging and the beneficial effects of exercise in old age. In addition, Olga had lower scores on memory, reasoning and speed tasks than the younger reference sample, but outperformed typical adults of age 90-95 on speed and memory. Together, our findings open the possibility of old-age benefits of increasing PA on WM microstructure and cognition despite age-related increase in WMH burden and HIPP shrinkage, and add to the still scarce neuroimaging data of the healthy oldest-old (>90 years) adults.

A moiré deflectometer for antimatter.

The precise measurement of forces is one way to obtain deep insight into the fundamental interactions present in nature. In the context of neutral antimatter, the gravitational interaction is of high interest, potentially revealing new forces that violate the weak equivalence principle. Here we report on a successful extension of a tool from atom optics--the moiré deflectometer--for a measurement of the acceleration of slow antiprotons. The setup consists of two identical transmission gratings and a spatially resolving emulsion detector for antiproton annihilations. Absolute referencing of the observed antimatter pattern with a photon pattern experiencing no deflection allows the direct inference of forces present. The concept is also straightforwardly applicable to antihydrogen measurements as pursued by the AEgIS collaboration. The combination of these very different techniques from high energy and atomic physics opens a very promising route to the direct detection of the gravitational acceleration of neutral antimatter.

Mycobacterium chelonae peritonitis in peritoneal dialysis. Literature review.

Non-tuberculous mycobacteria are a rare but serious cause of peritoneal dialysis-related peritonitis. There are no clear guidelines for treating non-tuberculous mycobacteria peritoneal dialysis-associated infections. It has been recommended that at least two antibiotics be given for a prolonged period and peritoneal catheter should be removed. This paper describes the clinical course and treatment of a patient with M. chelonae peritoneal dialysis-related peritonitis and reviews the previously published cases.

Precision measurement of the 6He half-life and the weak axial current in nuclei.

Studies of 6He beta decay along with tritium can play an important role in testing ab initio nuclear wave-function calculations and may allow for fixing low-energy constants in effective-field theories. Here, we present an improved determination of the 6He half-life to a relative precision of 3×10(-4). Our value of 806.89±0.11(stat)(-0.19syst)(+0.23) ms resolves a major discrepancy between previous measurements. Calculating the statistical rate function we determined the ft value to be 803.04(-0.23)(+0.26) s. The extracted Gamow-Teller matrix element agrees within a few percent with ab initio calculations.

Search for an annual modulation in a p-type Point Contact germanium dark matter detector.

Fifteen months of cumulative CoGeNT data are examined for indications of an annual modulation, a predicted signature of weakly interacting massive particle (WIMP) interactions. Presently available data support the presence of a modulated component of unknown origin, with parameters prima facie compatible with a galactic halo composed of light-mass WIMPs. Unoptimized estimators yield a statistical significance for a modulation of ∼2.8σ, limited by the short exposure.

Arrival time and magnitude of airborne fission products from the Fukushima, Japan, reactor incident as measured in Seattle, WA, USA.

We report results of air monitoring started due to the recent natural catastrophe on 11 March 2011 in Japan and the severe ensuing damage to the Fukushima Dai-ichi nuclear reactor complex. On 17-18 March 2011, we registered the first arrival of the airborne fission products (131)I, (132)I, (132)Te, (134)Cs, and (137)Cs in Seattle, WA, USA, by identifying their characteristic gamma rays using a germanium detector. We measured the evolution of the activities over a period of 23 days at the end of which the activities had mostly fallen below our detection limit. The highest detected activity from radionuclides attached to particulate matter amounted to 4.4 ± 1.3 mBq m(-3) of (131)I on 19-20 March.

Test of Lorentz invariance with spin precession of ultracold neutrons.

A clock comparison experiment, analyzing the ratio of spin precession frequencies of stored ultracold neutrons and 199Hg atoms, is reported. No daily variation of this ratio could be found, from which is set an upper limit on the Lorentz invariance violating cosmic anisotropy field b perpendicular < 2 x 10(-20) eV (95% C.L.). This is the first limit for the free neutron. This result is also interpreted as a direct limit on the gravitational dipole moment of the neutron |gn| < 0.3 eV/c2 m from a spin-dependent interaction with the Sun. Analyzing the gravitational interaction with the Earth, based on previous data, yields a more stringent limit |gn| < 3 x 10(-4) eV/c2 m.

Hemodialysis graft flow surveillance with prompt corrective interventions improves access long-term patency.

BACKGROUND: Hemodialysis arteriovenous graft (AVG) patency is dependent on favorable flow characteristics. We examined hemodynamic, humoral risk factors, and the effects of stringent flow surveillance coupled with prompt corrective intervention on long-term graft patency. METHODS: Over a 29-month period 92 chronic hemodialysis patients with AVG were evaluated monthly by flow surveillance. Clinical diagnosis of failing graft, which promoted angiography and corrective intervention was based on flow reduction, and patient's unique medical history and hemodynamic parameters. RESULTS: Graft arteriography revealed stenotic lesions in 94.5% of the cases, necessitating endovascular or surgical angioplasty. Low ejection fraction, early postoperative intervention, and low baseline flow were associated with a statistically significant reduction in intervention-free interval (p < 0.05). Mean AVG flow threshold prior to intervention was 463 +/- 154 ml/min, corresponding to a mean flow reduction of 45 +/- 12%. Total graft thrombosis rate was 0.21 thrombotic episodes/patient year. Primary graft patency at 6, 12, and 24 months was 76, 44 and 35%, and secondary patency 99, 97, 88%, respectively. CONCLUSIONS: Stringent flow surveillance policy coupled with prompt intervention has been proven effective in maintaining AVG long-term patency. Patients with decreased ejection fraction, early post-operative intervention, and low baseline AVG flow are prone to graft thrombosis.

Direct experimental verification of neutron acceleration by the material optical potential of solid 2H2.

We have measured the acceleration of neutrons by the material optical potential of solid 2H2. Using a gravitational spectrometer, we find a minimal kinetic energy Ec = (99+/-7) neV of neutrons from a superthermal ultracold neutron (UCN) source with solid 2H2 as an UCN converter. The result is in excellent agreement with theoretical predictions, Ec = 106 neV.

Birmingham Hip Resurfacing arthroplasty: short-term clinical and radiographic outcome.

BACKGROUND: Aim of our study was to evaluate the clinical and radiographic outcome of the first 300 consecutively implanted Birmingham Hip Resurfacing arthroplasties (BHR) in our department. METHODS: 300 BHR arthroplasties were performed in 263 patients until May 2003. Primary clinical endpoints of the investigation were the implant survival and the total Harris hip score, assessed at the last examination. RESULTS: At a median follow-up time of 24 months the Kaplan/Meier survivor estimate was 98%. 6 implant revisions were performed due to infection (2), malposition (1), femoral neck fracture (1), primary unstable cup (1) and chronic pain (1), respectively. The median Harris hip score improved from 51 points to 96 points at last follow-up. No hip showed radiographic signs of aseptic implant loosening. CONCLUSIONS: The preliminary experience with the BHR for the younger adult requiring hip arthroplasty is encouraging, but has to be reproduced in the long-term.

Direct experimental limit on neutron-mirror-neutron oscillations.

In case a mirror world with a copy of our ordinary particle spectrum would exist, the neutron n and its degenerate partner, the mirror neutron n', could potentially mix and undergo nn' oscillations. The interaction of an ordinary magnetic field with the ordinary neutron would lift the degeneracy between the mirror partners, diminish the n' amplitude in the n wave function and, thus, suppress its observability. We report an experimental comparison of ultracold neutron storage in a trap with and without superimposed magnetic field. No influence of the magnetic field is found and, assuming negligible mirror magnetic fields, a limit on the oscillation time taunn' > 103 s (95% C.L.) is derived.

Cold neutron energy dependent production of ultracold neutrons in solid deuterium.

A measurement of the production of ultracold neutrons from velocity-selected cold neutrons on gaseous and solid deuterium targets is reported. The expected energy dependence for two-particle collisions with well defined neutron and Maxwell-Boltzmann distributed molecular velocities is found for the gas target. The solid target data agree in shape with the phonon density-of-states curve and provide strong evidence for the phonon model including multiphonon excitations.

Combinatory effects of citrinin and ochratoxin A in immortalized human proximal tubule cells.

Ochratoxin A (OTA) and citrinin (CIT) are two mycotoxins often occurring together in grains and cereals. Although both are nephrotoxic and can induce apoptosis, combination effects have not been examined up to now. Therefore, the aim of this study was to take a close look at the interactions of citrinin and OTA in cultured human proximal tubule-derived cells (IHKE cells). The cytotoxicity of both mycotoxins was studied, measuring the metabolic activity and the cell number. Furthermore, caspase 3-activation as a marker for apoptosis was examined for both mycotoxin alone and in combination. The results show that citrinin had an antagonistic effect on ochratoxin A induced caspase 3-activation in concentrations of 2.5 and 5 µmol/l. Higher concentrations (7.5 and 15 µmol/l) lead to additive effects, lower citrinin concentrations (0.25 and 1 µmol/l) did not show any effect at all. The observed decrease in caspase 3-activity was specific for the combination with OTA, since the combination of citrinin with cisplatin did not show any effect. Citrinin did not influence of the OTA-induced apoptosis when added two hours after applying ochratoxin A. Also the combination of both toxins decreased the uptake of OTA into the cells which might be an explanation for the antagonistic effect of citrinin in certain concentrations. However, the transport into cells can not be the only explanation. so further examinations are necessary.

[Resurfacing arthroplasty of the hip]. / Oberflächenersatz am Hüftgelenk.

Currently, an increase in resurfacing arthroplasty in the treatment of hip osteoarthritis--especially in young adults--can be observed. New bearing technologies (mainly metal-on-metal surfaces) show better tribologic results than historical designs (e.g. the Wagner cup). At present, it is unclear whether these modifications and a definitively low dislocation rate--due to the large head diameter--can be supported by further good clinical results. The quantity as well as the quality of the available investigations prevents a definite opinion at the moment. Appropriate clinical studies with documented radiographic follow-up are necessary to compare the outcome of these new implants with standard techniques.

[Hip resurfacing arthroplasty]. / Hüftgelenk-Oberflächenersatzendoprothesen.

In comparison to stemmed total hip replacements, hip resurfacing offers advantages especially in joint stability and amount of femoral bone resection. After the poor results achieved with this concept that were mainly caused by failure of the materials used, reintroduction of the metal-on-metal bearing initiated a renaissance. This bearing, the cementless cup, and the improved surgical technique led to better short- to medium-term results. Revision and complication rates are now comparable to conventional total hip replacements. The functional capacity of the method is higher. Because long-term results are not available, however, questions remain, for instance, the consequences of the higher metal ion serum concentrations or the impossibility of changing the inlay when femoral revision becomes necessary.

[Functional results after surface replacement of the hip: comparison between dysplasia and idiopathic osteoarthritis]. / Funktionelle Behandlungsergebnisse nach Oberflächenersatz am Hüftgelenk: Vergleich zwischen Dysplasie- und idiopathischer Koxarthrosen.

AIM: To determine if there are differences in function after resurfacing arthroplasty of the hip in patients with primary osteoarthritis compared to patients with secondary osteoarthritis due to developmental dysplasia of the hip. METHOD: In a controlled prospective study of Birmingham Hip Resurfacing (BHR) we included all patients with primary osteoarthritis (n = 54, average age 48.4 years) and osteoarthritis due to high grade dysplasia (Eftekhar B, n = 34, average age 55.8 years). Standardized clinical (Harris hip score) and radiographic examinations were performed 6 weeks, 3 months and 6 months and then every year after the operation. RESULTS: All patients could be followed up to 1.5 years (1-4 years) after surgery. The average Harris hip score improved to 82-95 points in both groups 3 months postoperatively. Statistically significant differences could be found in the subscales "function" and "limp", where patients with dysplastic hips showed somewhat lower results after 6 (function) to 12 weeks (limp) postoperatively. This is probably attributable to extended non-weight-bearing after acetabular reconstruction in these cases, as the difference disappeared with full weight-bearing. Radiographically determined neck-shaft angles are slightly higher in dysplastic hips (142 degrees versus 135 degrees ), but we did not recognize any significant differences in implant positioning. CONCLUSION: The short- to mid-term results showed no clinically relevant functional differences after surface replacement in patients with primary osteoarthritis of the hip and patients with secondary osteoarthritis due to higher grade dysplasia. Long-term observation is necessary, however, to determine if these positive functional results are reflected by appropriate radiographic survival.