Persistent magnetic coherence in magnets.

When excited, the magnetization in a magnet precesses around the field in an anticlockwise manner on a timescale governed by viscous magnetization damping, after which any information carried by the initial actuation seems to be lost. This damping appears to be a fundamental bottleneck for the use of magnets in information processing. However, here we demonstrate the recall of the magnetization-precession phase after times that exceed the damping timescale by two orders of magnitude using dedicated two-colour microwave pump-probe experiments for a Y3Fe5O12 microstructured film. Time-resolved magnetization state tomography confirms the persistent magnetic coherence by revealing a double-exponential decay of magnetization correlation. We attribute persistent magnetic coherence to a feedback effect, that is, coherent coupling of the uniform precession with long-lived excitations at the minima of the spin-wave dispersion relation. Our finding liberates magnetic systems from the strong damping in nanostructures that has limited their use in coherent information storage and processing.

Large magnetic gap at the Dirac point in Bi2Te3/MnBi2Te4 heterostructures.

Magnetically doped topological insulators enable the quantum anomalous Hall effect (QAHE), which provides quantized edge states for lossless charge-transport applications1-8. The edge states are hosted by a magnetic energy gap at the Dirac point2, but hitherto all attempts to observe this gap directly have been unsuccessful. Observing the gap is considered to be essential to overcoming the limitations of the QAHE, which so far occurs only at temperatures that are one to two orders of magnitude below the ferromagnetic Curie temperature, TC (ref. 8). Here we use low-temperature photoelectron spectroscopy to unambiguously reveal the magnetic gap of Mn-doped Bi2Te3, which displays ferromagnetic out-of-plane spin texture and opens up only below TC. Surprisingly, our analysis reveals large gap sizes at 1 kelvin of up to 90 millielectronvolts, which is five times larger than theoretically predicted9. Using multiscale analysis we show that this enhancement is due to a remarkable structure modification induced by Mn doping: instead of a disordered impurity system, a self-organized alternating sequence of MnBi2Te4 septuple and Bi2Te3 quintuple layers is formed. This enhances the wavefunction overlap and size of the magnetic gap10. Mn-doped Bi2Se3 (ref. 11) and Mn-doped Sb2Te3 form similar heterostructures, but for Bi2Se3 only a nonmagnetic gap is formed and the magnetization is in the surface plane. This is explained by the smaller spin-orbit interaction by comparison with Mn-doped Bi2Te3. Our findings provide insights that will be crucial in pushing lossless transport in topological insulators towards room-temperature applications.

Valley-Polarized Quantum Hall Phase in a Strain-Controlled Dirac System.

In multivalley systems, the valley pseudospin offers rich physics going from encoding of information by its polarization (valleytronics), to exploring novel phases of matter when its degeneracy is changed. Here, by strain engineering, we reveal fully valley-polarized quantum Hall phases in the Pb_{1-x}Sn_{x}Se Dirac system. Remarkably, when the valley energy splitting exceeds the fundamental band gap, we observe a "bipolar quantum Hall phase," heralded by the coexistence of hole and electron chiral edge states at distinct valleys in the same quantum well. This suggests that spatially overlaid counterpropagating chiral edge states emerging at different valleys do not interfere with each other.

Giant magnon spin conductivity in ultrathin yttrium iron garnet films.

Conductivities are key material parameters that govern various types of transport (electronic charge, spin, heat and so on) driven by thermodynamic forces. Magnons, the elementary excitations of the magnetic order, flow under the gradient of a magnon chemical potential1-3 in proportion to a magnon (spin) conductivity. The magnetic insulator yttrium iron garnet is the material of choice for efficient magnon spin transport. Here we report a giant magnon conductivity in thin yttrium iron garnet films with thicknesses down to 3.7 nm when the number of occupied two-dimensional subbands is reduced from a large number to a few, which corresponds to a transition from three-dimensional to two-dimensional magnon transport. We extract a two-dimensional magnon spin conductivity around 1 S at room temperature, comparable to the (electronic) conductivity of the high-mobility two-dimensional electron gas in GaAs quantum wells at millikelvin temperatures4. Such high conductivities offer opportunities to develop low-dissipation magnon-based spintronic devices.

Observation of Magnon Polarization.

We measure the mode-resolved direction of the precessional motion of the magnetic order, i.e., magnon polarization, via the chiral term of inelastic polarized neutron scattering spectra. The magnon polarization is a unique and unambiguous signature of magnets and is important in spintronics, affecting thermodynamic properties such as the magnitude and sign of the spin Seebeck effect. However, it has never been directly measured in any material until this work. The observation of both signs of magnon polarization in Y_{3}Fe_{5}O_{12} also gives direct proof of its ferrimagnetic nature. The experiments agree very well with atomistic simulations of the scattering cross section.

Future directions for the concept of salutogenesis: a position article.

Aaron Antonovsky advanced the concept of salutogenesis almost four decades ago (Antonovsky, Health, Stress and Coping. Jossey-Bass, San Francisco, CA, 1979; Unravelling the Mystery of Health. Jossey-Bass, San Francisco, CA, 1987). Salutogenesis posits that life experiences shape the sense of coherence (SOC) that helps to mobilize resources to cope with stressors and manage tension successfully (determining one's movement on the health Ease/Dis-ease continuum). Antonovsky considered the three-dimensional SOC (i.e. comprehensibility, manageability, meaningfulness) as the key answer to his question about the origin of health. The field of health promotion has adopted the concept of salutogenesis as reflected in the international Handbook of Salutogenesis (Mittelmark et al., The Handbook of Salutogenesis. Springer, New York, 2016). However, health promotion mostly builds on the more vague, general salutogenic orientation that implies the need to foster resources and capacities to promote health and wellbeing. To strengthen the knowledge base of salutogenesis, the Global Working Group on Salutogenesis (GWG-Sal) of the International Union of Health Promotion and Education produced the Handbook of Salutogenesis. During the creation of the handbook and the regular meetings of the GWG-Sal, the working group identified four key conceptual issues to be advanced: (i) the overall salutogenic model of health; (ii) the SOC concept; (iii) the design of salutogenic interventions and change processes in complex systems; (iv) the application of salutogenesis beyond health sector. For each of these areas, we first highlight Antonovsky's original contribution and then present suggestions for future development. These ideas will help guide GWG-Sal's work to strengthen salutogenesis as a theory base for health promotion.

Observation of the spin Nernst effect.

The observation of the spin Hall effect triggered intense research on pure spin current transport. With the spin Hall effect, the spin Seebeck effect and the spin Peltier effect already observed, our picture of pure spin current transport is almost complete. The only missing piece is the spin Nernst (-Ettingshausen) effect, which so far has been discussed only on theoretical grounds. Here, we report the observation of the spin Nernst effect. By applying a longitudinal temperature gradient, we generate a pure transverse spin current in a Pt thin film. For readout, we exploit the magnetization-orientation-dependent spin transfer to an adjacent yttrium iron garnet layer, converting the spin Nernst current in Pt into a controlled change of the longitudinal and transverse thermopower voltage. Our experiments show that the spin Nernst and the spin Hall effect in Pt are of comparable magnitude, but differ in sign, as corroborated by first-principles calculations.

Single step, direct fluorescence immunoassays based on metal enhanced fluorescence (MEF-FIA) applicable as micro plate-, array-, multiplexing- or point of care-format.

Although Enzyme Linked Immuno Sorbent Assay (ELISA) technology is approaching it's 45th year of existence since first described in 1971, it is still the main diagnostic tool in clinical research and routine diagnostics. However, despite its broad usage it suffers from some drawbacks, limiting its use especially in more advanced assay formats like multiplexing platforms, point of care devices or protein arrays. Those limitations result from the need for an enzyme label, a soluble enzyme substrate, washing steps (multiplexing, point care, arrays) and in some cases also insufficient sensitivity, because the majority of circulating proteins and thus potential biomarkers may be found in lower sub-picomolar concentrations. We hereby present a new assay platform based on metal enhanced fluorescence (MEF), that remedies these problems since it eliminates the need for washing steps, for using enzyme labels and allows detection of analytes down to sub-picomolar concentrations. In addition this technology is fully compatible to standard fluorescence reader equipment as it is found in many laboratories nowadays. Since our present work is focused on single biomarker evaluation, we chose a 96 well plate format for convenience, but any other formate like antibody arrays, strip-like point of care devices etc. is feasible too.

Negative Longitudinal Magnetoresistance from the Anomalous N=0 Landau Level in Topological Materials.

Negative longitudinal magnetoresistance (NLMR) is shown to occur in topological materials in the extreme quantum limit, when a magnetic field is applied parallel to the excitation current. We perform pulsed and dc field measurements on Pb_{1-x}Sn_{x}Se epilayers where the topological state can be chemically tuned. The NLMR is observed in the topological state, but is suppressed and becomes positive when the system becomes trivial. In a topological material, the lowest N=0 conduction Landau level disperses down in energy as a function of increasing magnetic field, while the N=0 valence Landau level disperses upwards. This anomalous behavior is shown to be responsible for the observed NLMR. Our work provides an explanation of the outstanding question of NLMR in topological insulators and establishes this effect as a possible hallmark of bulk conduction in topological matter.

Decrease in mortality of adult epilepsy patients since 1980: lessons learned from a hospital-based cohort.

BACKGROUND AND PURPOSE: Data on mortality in patients with epilepsy have been available since the 1800s. They consistently show a 2-3-fold increase compared to the general population. Despite major advances in diagnostic tools and treatment options, there is no evidence for a decrease in premature deaths. The temporal trend of mortality in a hospital-based epilepsy cohort over three decades was assessed. METHODS: A hospital-based incidence cohort was recruited from a specialized epilepsy outpatient clinic at Innsbruck Medical University between 1980 and 2007, divided by decade into three cohorts and followed for 5 years after initial epilepsy diagnosis. Deaths and their primary causes were determined using probabilistic record linkage with the Austrian death registry. Age-, sex- and period-adjusted standardized mortality rates (SMRs) were computed in relation to the general population of the same area and grouped according to time of diagnosis. RESULTS: In all, 122 deaths in 4549.9 person-years (1954.5 women, 2595.2 men) were identified. The overall SMR was 2.2 [95% confidence interval (CI) 1.8-2.6] and decreased from 3.0 (95% CI 2.1-4.3) in 1980-1989, to 2.7 (95% CI 2.0-3.5) in 1990-1999 and to 1.4 (95% CI 1.0-2.0) in 2000-2007. CONCLUSIONS: This study indicates a decrease in mortality in newly diagnosed epilepsy patients over the last three decades. This may be due to advances in diagnosis and treatment over the past three decades, including early identification of drug resistance, introduction of new anti-epileptic drugs and establishment of a comprehensive epilepsy surgery programme in this region.

Periarticular injections with continuous perfusion of local anaesthetics provide better pain relief and better function compared to femoral and sciatic blocks after TKA: a randomized clinical trial.

PURPOSE: Combined femoral and sciatic nerve blocks for post-operative pain management following total knee arthroplasty (TKA) improve patient satisfaction, decrease narcotic consumption and improve pain. However, accompanying motoric weakness can cause falls and related complications. We wonder whether peri-capsular injections in combination with intra-articular perfusion of local anaesthetics would result in equal or less pain without the related complications of nerve blocks. The objective of the study was to verify these aspects in a prospective randomized trial comparing both treatments. METHODS: Fifty TKA patients randomly received either a femoral (continuous) and a sciatic (single-shot) nerve block (CFNB group, 25 knees) or periarticular infiltrations and a continuous post-operative intra-articular infusion (PIAC group, 25 knees). VAS for pain, pain medication consumption, functional assessment, straight leg raising as well as KSS were recorded post-operatively for 6 days. RESULTS: VAS (p < 0.001) and KSS (p = 0.05) were significantly better for PIAC. There was increased pain following CFNB compared to PIAC. Catheters stayed for 4 days, a pain 'rebound' occurred after removing in CFNB but not after PIAC. There was no difference in regard to knee function (n.s.), but straight leg raising was significant better following PIAC. There were two falls in patients with CFNB. CONCLUSION: Peri-capsular injections combined with an intra-articular catheter provide better pain control, no rebound pain with better function and might decrease the risk of complications related to motor weakness. LEVEL OF EVIDENCE: I.

Influence of tibial hybrid fixation on graft tension and stability in ACL double-bundle reconstruction.

PURPOSE: Initial graft tension in anterior cruciate ligament (ACL) reconstruction affects stability and tension loss at follow-up. This study investigated the influence of hybrid tibial fixation in 3-tunnel double-bundle ACL reconstruction on initial graft tension and tension change and stability under anterior and combined rotatory loads. METHODS: Eleven fresh-frozen cadaveric knees were reconstructed with an ACL double bundle using a 3-tunnel technique. Grafts were tightened to 80 N in 60° (AM bundle) and 15° (PL bundle) of flexion. Anterior tibial translation under 134 N of anterior shear load and translation under combined rotatory and valgus loads (10 Nm valgus stress, 4 Nm internal tibial torque) were determined at 0°, 30°, 60°, and 90° flexion. In addition, graft tension under continuous passive motion was determined. Intact, ACL-resected and ACL-reconstructed joints with either tibial extracortical graft fixation or extracortical plus supplemental aperture graft fixation (hybrid fixation) were tested. RESULTS: Hybrid fixation did not increase graft tension in either bundle during fixation or in motion without additional load. AM-bundle tension increased (p < 0.05) at 0° under combined rotatory and valgus loads and at 30° and 60° under both loading conditions without decreasing the anterior tibial translation. PL-bundle tension increased (p < 0.05) only at 90° under combined rotatory and valgus loads. CONCLUSIONS: Tibial hybrid fixation in 3-tunnel double-bundle ACL reconstruction increases time-zero AM- and PL-bundle tensions under loading conditions, generating greater construct stiffness. This could lead to a longer preservation of ACL-graft stability in clinical follow-up before bony incorporation.

Age-related effects of job characteristics on burnout and work engagement.

BACKGROUND: In light of an ageing and age-diverse workforce, it is imperative to understand how psychosocial aspects of work might influence health throughout working life. Recently, there has been an implicit call to differentiate job characteristics beyond the two factors of job demands and job resources. As needs, abilities and motivation fluctuate with age, different job characteristics might yield differential benefits. Additionally, markers beyond chronological age should be considered. AIMS: To explore systematically interactions between different job characteristics, age and age covariates (i.e. job tenure and position type) and their relationship with work-related health outcomes. METHODS: An online survey of workers in Switzerland, Austria and Germany, recruited through a panel data service provider. We excluded participants working fewer than 30 hours a week, trainees, self-employed people and senior managers. We assessed seven areas of psychosocial risks at work, burnout, work engagement and demographics. RESULTS: Of the 6000 workers contacted, 1916 responded (31%). After applying exclusion criteria, we analysed data from 1417 respondents. We found that age barely had a moderating effect between psychosocial factors and health outcomes, but its three-way interaction with age covariates had more explanatory potential. Young workers with high job tenure showed particular vulnerability to job demands and the lack of certain job resources. Older workers with managerial positions were more resilient. CONCLUSIONS: Age and its covariates, such as job tenure and position type, should be considered in developing age-sensitive occupational health models.

Magnetic-field-induced ferroelectric polarization reversal in the multiferroic Ge(1-x)Mn(x)Te semiconductor.

Ge(1-x)Mn(x)Te is shown to be a multiferroic semiconductor, exhibiting both ferromagnetic and ferroelectric properties. By ferromagnetic resonance we demonstrate that both types of order are coupled to each other. As a result, magnetic-field-induced ferroelectric polarization reversal is achieved. Switching of the spontaneous electric dipole moment is monitored by changes in the magnetocrystalline anisotropy. This also reveals that the ferroelectric polarization reversal is accompanied by a reorientation of the hard and easy magnetization axes. By tuning the GeMnTe composition, the interplay between ferromagnetism and ferroelectricity can be controlled.

Observation of the spin Peltier effect for magnetic insulators.

We report the observation of the spin Peltier effect (SPE) in the ferrimagnetic insulator yttrium iron garnet (YIG), i.e., a heat current generated by a spin current flowing through a platinum (Pt)|YIG interface. The effect can be explained by the spin transfer torque that transforms the spin current in the Pt into a magnon current in the YIG. Via magnon-phonon interactions the magnetic fluctuations modulate the phonon temperature that is detected by a thermopile close to the interface. By finite-element modeling we verify the reciprocity between the spin Peltier and spin Seebeck effect. The observed strong coupling between thermal magnons and phonons in YIG is attractive for nanoscale cooling techniques.

Work, work-life conflict and health in an industrial work environment.

BACKGROUND: Work-life conflict has been poorly studied as a cause of ill-health in occupational medicine. AIMS: To study associations between physical and psychosocial working conditions, including work-life conflict on the one hand and general, physical and mental health outcomes on the other. METHODS: Cross-sectional data were used from an employee survey among the workforces of four medium-sized and large companies in Switzerland. Physical work factors included five demands and exposures such as heavy loads, repetitive work and poor posture. Psychosocial factors included 14 demands and limited resources such as time pressure, overtime, monotonous work, job insecurity, low job autonomy, low social support and work-life conflict. Health outcomes studied were self-rated health, sickness absence, musculoskeletal disorders, sleep disorders, stress and burnout. RESULTS: There was a response rate of 49%; 2014 employees participated. All adverse working conditions were positively associated with several poor health outcomes in both men and women. After mutual adjustment for all work factors and additional covariates, only a few, mainly psychosocial work factors remained significant as risk factors for health. Work-life conflict, a largely neglected work-related psychosocial factor in occupational medicine, turned out to be the only factor that was significantly and strongly associated with all studied health outcomes and was consistently found to be the strongest or second strongest of all the studied risk factors. CONCLUSIONS: Even in an industrial work environment, psychosocial work factors, and particularly work-life conflict, play a key role and need to be taken into consideration in research and workplace health promotion.

Direct band gap wurtzite gallium phosphide nanowires.

The main challenge for light-emitting diodes is to increase the efficiency in the green part of the spectrum. Gallium phosphide (GaP) with the normal cubic crystal structure has an indirect band gap, which severely limits the green emission efficiency. Band structure calculations have predicted a direct band gap for wurtzite GaP. Here, we report the fabrication of GaP nanowires with pure hexagonal crystal structure and demonstrate the direct nature of the band gap. We observe strong photoluminescence at a wavelength of 594 nm with short lifetime, typical for a direct band gap. Furthermore, by incorporation of aluminum or arsenic in the GaP nanowires, the emitted wavelength is tuned across an important range of the visible light spectrum (555-690 nm). This approach of crystal structure engineering enables new pathways to tailor materials properties enhancing the functionality.

Long-term efficacy of selective laser trabeculoplasty in patients on prostaglandin therapy.

BACKGROUND: The aim of the study was to analyse the efficacy of selective laser trabeculoplasty in patients on medical therapy and to evaluate a possible influence of prostaglandin therapy on intraocular pressure reduction. PATIENTS AND METHODS: A retrospective chart review was undertaken of patients with ocular hypertension or open angle glaucoma who underwent selective laser trabeculoplasty between 3/2008 and 12/2010. Data were collected preoperatively, on the day of intervention, 1 day, 1 month and then every 3 months post selective laser trabeculoplasty. The main outcome measure was mean intraocular pressure reduction. RESULTS: 109 eyes (76 on prostaglandins) were included. Mean preoperative intraocular pressure was 22.3 ± 4.5 mmHg (prostaglandin naïve) and 19.2 ± 4.8 mmHg (on prostaglandin) (p=0.003). Up to 1 year follow-up, intraocular pressure was statistically significantly reduced in both groups (p ≤ 0.019). Eyes with a higher preoperative intraocular pressure had a greater pressure reduction (Spearman rho=0.387, p=0.002). Eyes naïve to prostaglandins initially had a greater reduction in intraocular pressure, although after 1 year of follow-up the difference was no longer statistically significant. CONCLUSIONS: Selective laser trabeculoplasty significantly reduces intraocular pressure in patients already on medical therapy. A sustained influence of prostaglandin therapy on the efficacy of selective laser trabeculoplasty was not found.

Long-term efficacy of selective laser trabeculoplasty in pseudophakic patients - a "real-life" analysis.

BACKGROUND: The aim of this study was to report on the course and long-term effect of selective laser trabeculoplasty on intraocular pressure of pseudophakic patients suffering from open angle glaucoma or ocular hypertension with insufficient intraocular pressure lowering despite maximally tolerated topical and systemic intraocular pressure lowering medication. PATIENTS AND METHODS: A retrospective chart review of patients who underwent selective laser trabeculoplasty (360°) between 2008 and 2010 at the University hospital Zurich was undertaken. Intraocular pressure values before intervention, on the day of the intervention, 1 day, 1 month, 3 months and every 3 months up to 43 months after the intervention were analysed with respect to lens status. RESULTS: Out of 153 treated eyes of 111 patients (mean age 70.6 years ± 11.13 SD) 40 were pseudophakic. Mean baseline intraocular pressures were 19.00 mmHg ± 4.61 in the pseudophakic group and 20.12 mmHg ± 4.89 in the phakic group. One month after selective laser trabeculoplasty intraocular pressure reduction measured between -0.33 and -4.10 mmHg (CI 95%) in the pseudophakic group and between -3.64 and -5.58 mmHg (CI 95%) in the phakic group, the difference at this time point was significant (p=0.01). Beyond one month after selective laser trabeculoplasty there was no statistically significant difference in intraocular pressure reduction between pseudophakic and phakic patients. The mean decrease in intraocular pressure from baseline to the last follow-up of 43 months was 0.67 mmHg in the pseudophakic group and 0.25 mmHg in the phakic group (p=0.72). CONCLUSIONS: One month after selective laser trabeculoplasty pseudophakic patients showed a statistically significant diminished reduction of intraocular pressure compared to phakic patients. Later on there was no statistically significant difference in intraocular pressure reduction between pseudophakic and phakic patients. Therefore we conclude that there was no clinically relevant influence of pseudophakia on the long-term effect of selective laser trabeculoplasty.

The development of internal pressure standards for in-house elastic wave velocity measurements in multi-anvil presses.

Ultrasonic systems are powerful tools to determine elastic wave velocities of minerals and materials at high pressure and temperature and have been extensively developed in recent decades. However, accurate measurement of sample length is required to convert travel times into wave velocities, limiting their use to synchrotron facilities or room temperature experiments in laboratories. We have made use of a close collaboration between the Bayerisches Geoinstiut and the P61B end-station beamline (PETRA III - DESY) to install ultrasonic systems and develop a novel dual travel time method for in situ pressure determination without the need for synchrotron radiation. Our method relies on the travel times of elastic waves through a reference material; it requires a thermocouple and is non-intrusive, with the reference material replacing the backing plate of the high-pressure assembly. Pressures obtained from this dual travel time method show excellent agreement with those obtained from x-ray diffraction using synchrotron radiation on standard materials. Our novel method enables in situ pressure determination at varying temperatures during in-house ultrasonic interferometry experiments. This allows us not only to determine the elastic behavior of minerals and materials but also to investigate phase diagrams, solidus, or liquidus conditions at varying pressures and temperatures during in-house experiments. During the installation of the pulse-echo ultrasonic system, we identified critical parameters for obtaining reliable data. While these requirements are well-known to experts, this study presents a comprehensive review of the different characteristics of ultrasonic systems, providing user-friendly guidelines for new users installing and operating such systems in high-pressure and high-temperature conditions.