Emergent nanoscale superparamagnetism at oxide interfaces.

Atomically sharp oxide heterostructures exhibit a range of novel physical phenomena that are absent in the parent compounds. A prominent example is the appearance of highly conducting and superconducting states at the interface between LaAlO3 and SrTiO3. Here we report an emergent phenomenon at the LaMnO3/SrTiO3 interface where an antiferromagnetic Mott insulator abruptly transforms into a nanoscale inhomogeneous magnetic state. Upon increasing the thickness of LaMnO3, our scanning nanoSQUID-on-tip microscopy shows spontaneous formation of isolated magnetic nanoislands, which display thermally activated moment reversals in response to an in-plane magnetic field. The observed superparamagnetic state manifests the emergence of thermodynamic electronic phase separation in which metallic ferromagnetic islands nucleate in an insulating antiferromagnetic matrix. We derive a model that captures the sharp onset and the thickness dependence of the magnetization. Our model suggests that a nearby superparamagnetic-ferromagnetic transition can be gate tuned, holding potential for applications in magnetic storage and spintronics.

Preoperative pregabalin administration significantly reduces postoperative opioid consumption and mechanical hyperalgesia after transperitoneal nephrectomy.

BACKGROUND: Preoperative administration of pregabalin is proposed as a promising way of enhancing postoperative pain control. Whereas a few studies have investigated the effect of pregabalin on postoperative opioid consumption, no study has focused on the influence on postoperative hyperalgesia. In this randomized, triple-blinded, placebo-controlled study, we aimed to demonstrate that a single, preoperative dose of pregabalin reduces postoperative opioid consumption, mechanical hyperalgesia, and pain sensitivity. METHODS: Patients undergoing elective transperitoneal nephrectomy received 300 mg pregabalin or placebo 1 h before anaesthesia. After operation, patients received piritramide via a patient-controlled analgesia device. Pain levels and side-effects were documented. The area of hyperalgesia for punctuate mechanical stimuli around the incision was measured 48 h after the operation with a hand-held von Frey filament. Mechanical pain threshold was tested before and 48 h after surgery with von Frey filaments with increasing diameters. RESULTS: In each group, 13 patients were recruited. Total piritramide consumption [77 (16) vs 52 (16) mg, P=0.0004] and the normalized area of hyperalgesia [143 (87) vs 84 (54) cm(2), P=0.0497] were significantly decreased in the pregabalin group. There were no significant differences in mechanical pain threshold levels [1.20 (0.56) log(g) vs 1.05 (0.58) log(g), P=0.6738]. No case of severe sedation was reported in both groups. No other side-effects were observed. CONCLUSIONS: Our study has shown that preoperative administration of 300 mg pregabalin in patients undergoing transperitoneal nephrectomy reduces postoperative opioid consumption and decreases the area of mechanical hyperalgesia.

[Pain assessment in patients with dementia]. / Schmerzerfassung bei Demenz.

Recent literature demonstrates that pain in patients with dementia is often undertreated. This can partially be explained by a lack of training in the possibilities of assessing pain in patients with dementia. Subjective reports are the most valid approach for the assessment of the subjective experience of pain and should therefore be preferred over other methods. The assessment of the context, behavior, and physiological markers is advised if the patient is unable to provide a subjective report. Pain assessment scales are useful for documentation and monitoring.

[Pregabalin and postoperative hyperalgesia. A review]. / Pregabalin und postoperative Hyperalgesie. Ein Review.

Numerous studies support the theory that pregabalin causes an antihyperalgesic effect, which could be potentially beneficial in a perioperative setting. By binding to calcium channels pregabalin reduces the release of excitatory neurotransmitters and therefore inhibits central sensitization. Animal studies clearly demonstrated the antihyperalgesic potency of pregabalin but human experiments are, however, inconclusive. Clinical studies with quantitative sensory testing have not yet been published. Although strongly supported by theoretical considerations the routine preoperative application of pregabalin for the prevention of hyperalgesia cannot be recommended due to the lack of clinical studies. Future studies should incorporate secondary hyperalgesia and allodynia as primary parameters.

Metal-insulator transition in a system of superconducting vortices caused by a metallic gate.

We address a recent experiment in which a strong decrease of the resistance of a superconducting film has been observed when a remote unbiased gate was placed above the film. Here we explain the experimental finding as a suppression of the vortex tunneling due to the orthogonality catastrophe of the electrons inside the gate. We interpret the change in the resistance of the film as a "metal-insulator" transition in the system of vortices induced by the gate.

[Helping patients with risky health behaviors: some suggestions for motivational interviewing]. / "Combien de fois il faut que je vous dise...". Quelques pistes données par l'entretien motivationnel.

Helping patients modify risky health behaviors, including cigarette smoking, at-risk alcohol use, sedentary lifestyle and unhealthy diet, is a common and sometimes frustrating task. Motivational interviewing was developed from the notion that simple advice usually does not lead to behavioral change and may be even misperceived by patients. Based on active listening and an empathic attitude, some principles of motivational interviewing may be easily adapted to a primary care consultation. These principles facilitate positive, relaxed and constructive atmosphere for behavior change discussions and have been associated with promising results. This article presents key concepts of motivational interviewing such as ambivalence, resistance and stages of change, illustrated with practical examples.