Direct observation of antiferromagnetic parity violation in the electronic structure of Mn2Au.

Using momentum microscopy with sub-µm spatial resolution, allowing momentum resolved photoemission on individual antiferromagnetic domains, we observe an asymmetry in the electronic band structure,E(k)≠E(-k), in Mn2Au. This broken band structure parity originates from the combined time and parity symmetry,PT, of the antiferromagnetic order of the Mn moments, in connection with spin-orbit coupling. The spin-orbit interaction couples the broken parity to the Néel order parameter direction. We demonstrate a novel tool to image the Néel vector direction,N, by combining spatially resolved momentum microscopy withab-initiocalculations that correlate the broken parity with the vectorN.

Time-of-flight photoelectron momentum microscopy with 80-500 MHz photon sources: electron-optical pulse picker or bandpass pre-filter.

The small time gaps of synchrotron radiation in conventional multi-bunch mode (100-500 MHz) or laser-based sources with high pulse rate (∼80 MHz) are prohibitive for time-of-flight (ToF) based photoelectron spectroscopy. Detectors with time resolution in the 100 ps range yield only 20-100 resolved time slices within the small time gap. Here we present two techniques of implementing efficient ToF recording at sources with high repetition rate. A fast electron-optical beam blanking unit with GHz bandwidth, integrated in a photoelectron momentum microscope, allows electron-optical `pulse-picking' with any desired repetition period. Aberration-free momentum distributions have been recorded at reduced pulse periods of 5 MHz (at MAX II) and 1.25 MHz (at BESSY II). The approach is compared with two alternative solutions: a bandpass pre-filter (here a hemispherical analyzer) or a parasitic four-bunch island-orbit pulse train, coexisting with the multi-bunch pattern on the main orbit. Chopping in the time domain or bandpass pre-selection in the energy domain can both enable efficient ToF spectroscopy and photoelectron momentum microscopy at 100-500 MHz synchrotrons, highly repetitive lasers or cavity-enhanced high-harmonic sources. The high photon flux of a UV-laser (80 MHz, <1 meV bandwidth) facilitates momentum microscopy with an energy resolution of 4.2 meV and an analyzed region-of-interest (ROI) down to <800 nm. In this novel approach to `sub-µm-ARPES' the ROI is defined by a small field aperture in an intermediate Gaussian image, regardless of the size of the photon spot.

Trends in Patient Safety of Intact Abdominal Aortic Aneurysm Repair: German Registry Data on 36,594 Procedures.

OBJECTIVE/BACKGROUND: The study aim was to determine whether patient safety for non-ruptured abdominal aortic aneurysm (nrAAA) repair has changed between 1999 and 2010 in a large German cohort. METHODS: The data source was the prospective quality assurance registry of the German Vascular Society from 1999 to 2010. Patient characteristics, surgical techniques (open aortic repair [OAR], endovascular aortic repair [EVAR]), procedural time and outcomes, including the length of hospital stay (LOS), were analysed using the Cochran-Armitage test for binary parameters and Spearman's correlation coefficient for quantitative parameters. RESULTS: A total of 36,594 operations (23,037 OAR, 13,557 EVAR) for infrarenal nrAAA in 201 hospitals in Germany were investigated. Patients' mean age increased from 69.6 to 72.0 years (p < .001). The rate of patients with American Society of Anesthesiologists scores of 3 or 4 increased (p < .001). Use of EVAR increased (1999: 16.7%; 2010: 62.7%; p < .001), and since 2009, EVAR has been more frequently used than OAR. The overall in hospital mortality decreased from 3.1% in 1999 to 2.3% in 2010 (p < .001). There were no temporal trends for mortality rates for EVAR (p = .233) or OAR (p = .281) when considered separately. Cardiac (1999: 8.1%; 2010: 5.1%; p < .001) and pulmonary (1999: 7.8%; 2010: 4.8%; p < .001) complications decreased. The rate of post-operative renal failure increased (1999: 3.6%; 2010 4.1%; p = .017), without increasing the rate of patients needing dialysis (1999: 1.7%; 2010: 1.7%; p = .171). The median LOS decreased from 17 days in 1999 to 10 days in 2010 (p < .001). CONCLUSION: This study shows significantly improved post-procedural in hospital outcomes and decreased use of resources for nrAAA repair. This trend can probably be attributed to the implementation of EVAR as a standard technique, but some trends could also possibly be explained by a change in the remuneration system. The main limitation of the registry is the lack of internal and external validation. However, in hospital patient safety for AAA repair seems to have improved significantly in the participating hospitals.

Patient characteristics and outcomes of carotid endarterectomy and carotid artery stenting: analysis of the German mandatory national quality assurance registry - 2003 to 2014.

AIM: In Germany, every surgical or endovascular procedure on the extracranial carotid artery is documented in a mandatory quality assurance registry. The purpose of this study is to describe the patient characteristics, the indications for treatment, and the short-term outcomes as well as to analyse the corresponding trends from 2003 to 2014. METHODS: Data on demographics, peri-procedural measures, and outcomes were extracted from the annual quality reports published by the Federal Agency for Quality Assurance and the Institute for Applied Quality Improvement and Research in Health Care. Data were available from 2003 to 2014 for carotid endarterectomy (CEA) and from 2012 to 2014 for carotid artery stenting (CAS). The primary outcome event of this study is any stroke or death until discharge from hospital. Temporal trends of categorical variables were statistically analysed using the Cochran-Armitage test for trend. RESULTS: Between 2003 and 2014, 309,405 CEAs and 18,047 CAS procedures were documented in the database; 68.1% of all patients were male. The mean age of patients treated with CEA increased from 68.9 years in 2003 to 70.9 years in 2014. The proportion of patients with ASA stages III to V increased from 65% to 71% in CEA, whereas it decreased from 44% to 41% in CAS patients. 53.1% of all CEAs were performed for asymptomatic patients (group A), 34.4% for symptomatic patients treated electively (group B), and 11.2% a in a collective group including other indications for CEA or CAS (such as recurrent stenosis, carotid aneurysms, emergency treatment due to stroke-in-evolution). The corresponding data for CAS are 49.3%, 26.1% and 26.3% respectively. In group B, the interval between the neurological index event and CEA decreased from 28 to 8 days (P<0.001). In patients treated with CAS, this interval was 9 days in 2012 (no further data available). On average, 67.1% and 48.2% of surgically treated patients as well as 77.8% and 69.8% of CAS patients were neurologically assessed before and after the procedure, respectively. From 2003 to 2014, CEA procedures were performed more frequently in locoregional anesthesia (10.1% to 29.1%, P<0.001). The same trend was observed for the application of the eversion technique (37.0% to 41.6%, P<0.001), the neurophysiological monitoring (49.8% to 61.8%, P<0.001), and the intra-procedural assessment of the treated artery (44.5% to 69.7%, P<0.001). In contrast, shunting was used less frequently (48.1% to 43.0%, P<0.001). Averagely 95.7% of all endovascular procedures were performed using stent-angioplasty. In 54.2% a protection device was used. Nitinol and bare metal stents were used in 74.1% and 21.4% of cases, respectively. The in-hospital rate of any stroke or death decreased from 2.0% to 1.1% in asymptomatic patients treated with CEA without a contralateral stenosis ≥75% or occlusion, P<0.001). In patients treated with CAS this rate did not increase (1.7% to 1.8%, p=0.909). The corresponding rates in CEA and CAS patients with severe contralateral stenosis or occlusion varied between 1.9%-3.1% and 2.2%-2.6%, respectively. In symptomatic patients (group B) with a stenosis of 50 percent or more, the rate of any stroke or death decreased significantly after CEA from 4.2% to 2.4% (P<0.001) and remained stable after CAS (3.9% to 3.5%, P=0.577). CONCLUSION: This report on 327,452 carotid procedures analysed one of the largest quality registries on CEA and CAS worldwide. Data indicate that treated patients became older and sicker, whereas in contrast, the in-hospital rates of stroke or death are decreasing over time.

Stroke risk in the early period after carotid related symptoms: a systematic review.

Current guidelines recommend performing carotid endarterectomy in patients with symptomatic carotid disease as soon as possible after the neurological index event. However, early stroke risk has not been well documented for this patient group. We therefore conducted a systematic analysis of the current literature on the recurrent risk of ischemic events in patients with symptomatic carotid stenosis. Systematic review was performed by searching the MEDLINE® database from 1950 until June 8, 2015 (key words: cerebral ischemia, transient ischemic attack, amaurosis fugax, stroke, symptomatic carotid stenosis, recurrent risk, outcome, prognosis, follow-up, cohort and natural history). All studies reporting stroke risks in patients with symptomatic carotid stenosis after neurologic index events within a period of 7 days were included. Cumulative stroke risks with 95% confidence intervals after a neurologic index event were recalculated at 2-3, 7, 14 and 30 days and a meta-analysis including an analysis of heterogeneity were performed using the statistical package R and Excel for Mac 2003. Ten studies with a total number of 2634 patients were included. Results of an overall stroke risk were as follows: 2.0-17.2% at 2-3 days, 0-22.1% at 7 days, 0-29.6% at 14 days and 0-11.1% at 30 days in patients with a symptomatic extracranial carotid stenosis. The pooled stroke risk in the six studies with active follow-up was 6.0% (95% CI 2.4-14.4) at 2-3 days, 10.9% (6.1-18.7) at 7 days and 17.6% (9.7-29.9) at 14 days. Pooled stroke risk in the three studies with uncensored populations was even higher with 6.4% (1.5-23.8%) at 2-3 days, 19.5% (12.7-28.7) at 7 days and 26.1% (20.6-32.5%) at 14 days. Significant heterogeneity (P<0.001) could be explained by the different inclusion criteria and the study's design. Retrospective studies with passive follow-up had the lowest stroke risk whereas prospective studies with active follow-up and without bias through early intervention by carotid endarterectomy or carotid stenting had the highest stroke risk. The risk of recurrence of cerebrovascular events in patients with symptomatic carotid stenosis within the first days after a neurologic index event is as high as 6.4% (1.5-23.8), 19.5% (12.7-28.7) and 26.1% (20.6-32.5) after 2-3, 7 and 14 days respectively. Patients with a symptomatic carotid stenosis are therefore at a very high risk of a definitive stroke. Recommendations by current guidelines to perform carotid endarterectomy as soon as possible after the neurologic index event are therefore justified.

Ultrasound surveillance after CAS and CEA: what's the evidence?

AIM: The rationale of clinical and Duplex ultrasound (DUS) surveillance after carotid endarterectomy (CEA) and carotid artery stenting (CAS) is the detection of recurrent stenoses and the prevention of future carotid-related cerebral ischemic events. This paper addresses the evidence for this approach. METHODS: The multicenter randomized controlled trials (RCTs) published between 1990 and 2013 were reviewed with respect to DUS surveillance intervals, recurrent stenoses rates and recurrent ipsilateral stroke rates. In addition a Medline literature search from January 1990 until February 2014 was performed by use of the following keywords: "surveillance"; "carotid endarterectomy"; "carotid stenting"; "carotid artery surveillance"; "carotid artery stenosis". Finally we analyzed all carotid-related guidelines published between 2006 and 2013 for recommendations on DUS surveillance after CEA or CAS. RESULTS: Nine RCT protocols (NASCET, ECST, ACST, ACAS, CAVATAS, SAPPHIRE, EVA-3S, CREST, and SPACE) showed similar follow-up intervals (at 1 month, 3 or 4 and at 6, and 12 months after CAS and CEA, then at least once a year). The incidence of a recurrent carotid stenosis (≥50%) or occlusion ranged around 6% four years after CEA or CAS. The annual incidence of any ipsilateral cerebral ischemic event was about 1% and 0.5% after CEA for a symptomatic or an asymptomatic stenosis respectively. Since the overall incidence of carotid recurrent stenosis and postprocedural strokes is low, DUS is questioned as necessary for all patients after CEA and CAS in prospective single center series. However, certain subgroups of patients (women, diabetics, patients with dyslipidemia, smokers) might have increased rates of restenosis after CEA or CAS. Data on DUS surveillance intervals following CAS is rare. Three out of 21 identified guidelines recommend long-term DUS surveillance, as the benefits are considered to exceed the risks. However, the level of evidence for any recommendation on DUS surveillance is consistently low. CONCLUSION: Our literature review reveals only little evidence to support routine DUS after CEA within short intervals. Currently a practice with one periprocedural DUS and one DUS after 12 months after CEA seems to be reasonable. In patients with an ipsilateral restenosis≥50%, contralateral disease progression≥50% and in patients who are considered to be at higher risk of restenosis further DUS surveillance seems appropriate. Due to inconsistent long-term data on surveillance after CAS imaging at 6 months and then annually seems reasonable. Further studies on DUS surveillance are necessary.

Full tunability of strain along the fcc-bcc bain path in epitaxial films and consequences for magnetic properties.

Strained coherent film growth is commonly either limited to ultrathin films or low strains. Here, we present an approach to achieve high strains in thicker films, by using materials with inherent structural instabilities. As an example, 50 nm thick epitaxial films of the Fe70Pd30 magnetic shape memory alloy are examined. Strained coherent growth on various substrates allows us to adjust the tetragonal distortion from c/a{bct}=1.09 to 1.39, covering most of the Bain transformation path from fcc to bcc crystal structure. Magnetometry and x-ray circular dichroism measurements show that the Curie temperature, orbital magnetic moment, and magnetocrystalline anisotropy change over broad ranges.

[The anatomical precontoured Meves compression plate: surgical treatment of clavicular nonunion]. / Die anatomisch präkonturierte Platte nach Meves: operative Behandlung von Klavikulapseudarthrosen.

BACKGROUND: Pseudarthroses of the clavicle after fractures of the medial third often present with local pain, compromised shoulder function, or neurovascular symptoms. Reconstruction of normal clavicular anatomy and solid fusion is a prerequisite for good clinical outcome after surgical treatment. In this study, 24 patients with clavicular pseudarthrosis were treated with the anatomical precontoured Meves plate. In 11 patients, additional bone grafting was done. METHOD: Nineteen patients could be reexamined with a mean follow-up of 74.5 months. In all of them, solid fusion was achieved. RESULTS: The Constant score improved from 70.4 points preoperatively up to 82.5 points postoperatively (89.3% age-related). Sixteen patients were satisfied or very satisfied with the operative result. CONCLUSION: In our patients, secure healing of clavicular nonunion was achieved with the anatomical precontoured Meves plate, with good or excellent clinical outcomes.

Optical magnetic circular dichroism in threshold photoemission from a magnetite thin film.

Threshold photoemission excited by polarization-modulated ultraviolet femtosecond laser light is exploited for phase-sensitive detection of magnetic circular dichroism (MCD) for a magnetite thin film. Magnetite (Fe(3)O(4)) shows a magnetic circular dichroism of ∼(4.5 ± 0.3) × 10(-3) for perpendicularly incident circularly polarized light and a magnetization vector switched parallel and antiparallel to the helicity vector by an external magnetic field. The asymmetry in threshold photoemission is discussed in comparison to the magneto-optical Kerr effect. The optical MCD contrast in threshold photoemission will provide a basis for future laboratory photoemission studies on magnetic surfaces.

Bone marrow transplantation for acute leukemia in second or subsequent remission.

Twenty-one patients with acute leukemia in second to fifth remission were treated with bone marrow transplantation: 19 patients with transplants from HLA-matched siblings and two with transplants from identical twins. Twelve patients survived from 15 to 1,625 days after transplantation: six of 11 in the ALL group and six of 10 in the AML group. Recurrence of leukemia after marrow transplantation occurred in five patients. The cause of death in five patients was infection, in two patients combined with graft-versus-host disease. Long-term disease-free survival can probably be achieved in 30%-35% of all patients with acute leukemia who receive a marrow transplant in second or subsequent remission.